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/*
* Copyright 2018-2024 John A. De Goes and the ZIO Contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package zio.stream
import zio._
import zio.internal.{PartitionedRingBuffer, SingleThreadedRingBuffer, UniqueKey}
import zio.metrics.MetricLabel
import zio.stacktracer.TracingImplicits.disableAutoTrace
import zio.stm._
import zio.stream.ZStream.{DebounceState, HandoffSignal, failCause, zipChunks}
import zio.stream.internal.{ZInputStream, ZReader}
import java.io.{IOException, InputStream}
import scala.annotation.tailrec
import scala.collection.mutable
import scala.reflect.ClassTag
final class ZStream[-R, +E, +A] private (val channel: ZChannel[R, Any, Any, Any, E, Chunk[A], Any]) { self =>
import ZStream.HaltStrategy
/**
* Returns a new ZStream that applies the specified aspect to this ZStream.
* Aspects are "transformers" that modify the behavior of their input in some
* well-defined way (for example, adding a timeout).
*/
def @@[LowerR <: UpperR, UpperR <: R, LowerE >: E, UpperE >: LowerE, LowerA >: A, UpperA >: LowerA](
aspect: => ZStreamAspect[LowerR, UpperR, LowerE, UpperE, LowerA, UpperA]
)(implicit trace: Trace): ZStream[UpperR, LowerE, LowerA] =
ZStream.suspend(aspect(self))
/**
* Symbolic alias for [[ZStream#cross]].
*/
def <*>[R1 <: R, E1 >: E, A2](that: => ZStream[R1, E1, A2])(implicit
zippable: Zippable[A, A2],
trace: Trace
): ZStream[R1, E1, zippable.Out] =
self cross that
/**
* Symbolic alias for [[ZStream#crossLeft]].
*/
def <*[R1 <: R, E1 >: E, A2](that: => ZStream[R1, E1, A2])(implicit trace: Trace): ZStream[R1, E1, A] =
self crossLeft that
/**
* Symbolic alias for [[ZStream#crossRight]].
*/
def *>[R1 <: R, E1 >: E, A2](that: => ZStream[R1, E1, A2])(implicit trace: Trace): ZStream[R1, E1, A2] =
self crossRight that
/**
* Symbolic alias for [[ZStream#zip]].
*/
def <&>[R1 <: R, E1 >: E, A2](that: => ZStream[R1, E1, A2])(implicit
zippable: Zippable[A, A2],
trace: Trace
): ZStream[R1, E1, zippable.Out] =
self zip that
/**
* Symbolic alias for [[ZStream#zipLeft]].
*/
def <&[R1 <: R, E1 >: E, A2](that: => ZStream[R1, E1, A2])(implicit trace: Trace): ZStream[R1, E1, A] =
self zipLeft that
/**
* Symbolic alias for [[ZStream#zipRight]].
*/
def &>[R1 <: R, E1 >: E, A2](that: => ZStream[R1, E1, A2])(implicit trace: Trace): ZStream[R1, E1, A2] =
self zipRight that
/**
* Symbolic alias for [[ZStream#via]].
*/
def >>>[R1 <: R, E1 >: E, B](pipeline: => ZPipeline[R1, E1, A, B])(implicit
trace: Trace
): ZStream[R1, E1, B] =
via(pipeline)
/**
* Symbolic alias for [[[zio.stream.ZStream!.run[R1<:R,E1>:E,B]*]]].
*/
def >>>[R1 <: R, E1 >: E, A2 >: A, Z](sink: => ZSink[R1, E1, A2, Any, Z])(implicit
trace: Trace
): ZIO[R1, E1, Z] =
self.run(sink)
/**
* Symbolic alias for [[ZStream#concat]].
*/
def ++[R1 <: R, E1 >: E, A1 >: A](that: => ZStream[R1, E1, A1])(implicit trace: Trace): ZStream[R1, E1, A1] =
self concat that
/**
* Symbolic alias for [[ZStream#orElse]].
*/
def <>[R1 <: R, E2, A1 >: A](
that: => ZStream[R1, E2, A1]
)(implicit ev: CanFail[E], trace: Trace): ZStream[R1, E2, A1] =
self orElse that
/**
* A symbolic alias for `orDie`.
*/
def !(implicit ev1: E <:< Throwable, ev2: CanFail[E], trace: Trace): ZStream[R, Nothing, A] =
self.orDie
/**
* Returns a stream that submerges the error case of an `Either` into the
* `ZStream`.
*/
def absolve[R1 <: R, E1, A1](implicit
ev: ZStream[R, E, A] <:< ZStream[R1, E1, Either[E1, A1]],
trace: Trace
): ZStream[R1, E1, A1] =
ZStream.absolve(ev(self))
/**
* Aggregates elements of this stream using the provided sink for as long as
* the downstream operators on the stream are busy.
*
* This operator divides the stream into two asynchronous "islands". Operators
* upstream of this operator run on one fiber, while downstream operators run
* on another. Whenever the downstream fiber is busy processing elements, the
* upstream fiber will feed elements into the sink until it signals
* completion.
*
* Any sink can be used here, but see [[ZSink.foldWeightedZIO]] and
* [[ZSink.foldUntilZIO]] for sinks that cover the common usecases.
*/
def aggregateAsync[R1 <: R, E1 >: E, A1 >: A, B](
sink: => ZSink[R1, E1, A1, A1, B]
)(implicit trace: Trace): ZStream[R1, E1, B] =
aggregateAsyncWithin(sink, Schedule.forever)
/**
* Like `aggregateAsyncWithinEither`, but only returns the `Right` results.
*
* @param sink
* used for the aggregation
* @param schedule
* signalling for when to stop the aggregation
* @return
* `ZStream[R1, E2, B]`
*/
def aggregateAsyncWithin[R1 <: R, E1 >: E, A1 >: A, B](
sink: => ZSink[R1, E1, A1, A1, B],
schedule: => Schedule[R1, Option[B], Any]
)(implicit trace: Trace): ZStream[R1, E1, B] =
aggregateAsyncWithinEither(sink, schedule).collectRight
/**
* Aggregates elements using the provided sink until it completes, or until
* the delay signalled by the schedule has passed.
*
* This operator divides the stream into two asynchronous islands. Operators
* upstream of this operator run on one fiber, while downstream operators run
* on another. Elements will be aggregated by the sink until the downstream
* fiber pulls the aggregated value, or until the schedule's delay has passed.
*
* Aggregated elements will be fed into the schedule to determine the delays
* between pulls.
*
* @param sink
* used for the aggregation
* @param schedule
* signalling for when to stop the aggregation
* @return
* `ZStream[R1, E2, Either[C, B]]`
*/
def aggregateAsyncWithinEither[R1 <: R, E1 >: E, A1 >: A, B, C](
sink: => ZSink[R1, E1, A1, A1, B],
schedule: => Schedule[R1, Option[B], C]
)(implicit trace: Trace): ZStream[R1, E1, Either[C, B]] = {
type HandoffSignal = ZStream.HandoffSignal[E1, A]
import ZStream.HandoffSignal._
type SinkEndReason = ZStream.SinkEndReason
import ZStream.SinkEndReason._
val layer =
ZStream.Handoff.make[HandoffSignal] <*>
Ref.make[SinkEndReason](ScheduleEnd) <*>
Ref.make(Chunk[A1]()) <*>
schedule.driver <*>
Ref.make(false) <*>
Ref.make(false)
ZStream.fromZIO(layer).flatMap {
case (handoff, sinkEndReason, sinkLeftovers, scheduleDriver, consumed, endAfterEmit) =>
lazy val handoffProducer: ZChannel[Any, E1, Chunk[A], Any, Nothing, Nothing, Any] =
ZChannel.readWithCause(
(in: Chunk[A]) => ZChannel.fromZIO(handoff.offer(Emit(in)).when(in.nonEmpty)) *> handoffProducer,
(cause: Cause[E1]) => ZChannel.fromZIO(handoff.offer(Halt(cause))),
(_: Any) => ZChannel.fromZIO(handoff.offer(End(UpstreamEnd)))
)
lazy val handoffConsumer: ZChannel[Any, Any, Any, Any, E1, Chunk[A1], Unit] =
ZChannel.unwrap(
sinkLeftovers.getAndSet(Chunk.empty).flatMap { leftovers =>
if (leftovers.nonEmpty) {
consumed.set(true) *> ZIO.succeed(ZChannel.write(leftovers) *> handoffConsumer)
} else
handoff.take.map {
case Emit(chunk) =>
ZChannel.fromZIO(consumed.set(true)) *>
ZChannel.write(chunk) *>
ZChannel.fromZIO(endAfterEmit.get).flatMap {
case false => handoffConsumer
case true => ZChannel.unit
}
case Halt(cause) => ZChannel.refailCause(cause)
case End(ScheduleEnd) =>
ZChannel.unwrap {
consumed.get.map { p =>
if (p) ZChannel.fromZIO(sinkEndReason.set(ScheduleEnd) *> endAfterEmit.set(true))
else
ZChannel
.fromZIO(sinkEndReason.set(ScheduleEnd) *> endAfterEmit.set(true)) *> handoffConsumer
}
}
case End(reason) => ZChannel.fromZIO(sinkEndReason.set(reason) *> endAfterEmit.set(true))
}
}
)
def timeout(lastB: Option[B]): ZIO[R1, None.type, C] =
scheduleDriver.next(lastB)
def scheduledAggregator(
sinkFiber: Fiber.Runtime[E1, (Chunk[Chunk[A1]], B)],
scheduleFiber: Fiber.Runtime[None.type, C],
scope: Scope
): ZChannel[R1, Any, Any, Any, E1, Chunk[Either[C, B]], Any] = {
val forkSink =
consumed.set(false) *> endAfterEmit
.set(false) *> (handoffConsumer pipeToOrFail sink.channel).collectElements.run.forkIn(scope)
def handleSide(leftovers: Chunk[Chunk[A1]], b: B, c: Option[C]) =
ZChannel.unwrap(
sinkLeftovers.set(leftovers.flatten) *>
sinkEndReason.get.map {
case ScheduleEnd =>
ZChannel.unwrap {
for {
consumed <- consumed.get
sinkFiber <- forkSink
scheduleFiber <- timeout(Some(b)).forkIn(scope)
toWrite = c.fold[Chunk[Either[C, B]]](Chunk.single(Right(b)))(c => Chunk(Right(b), Left(c)))
} yield
if (consumed)
ZChannel
.write(toWrite) *> scheduledAggregator(sinkFiber, scheduleFiber, scope)
else scheduledAggregator(sinkFiber, scheduleFiber, scope)
}
case UpstreamEnd =>
ZChannel.unwrap {
consumed.get.map { p =>
if (p) ZChannel.write(Chunk.single(Right(b)))
else ZChannel.unit
}
}
}
)
ZChannel.unwrap {
sinkFiber.join.raceWith(scheduleFiber.join)(
(sinkExit, _) =>
scheduleFiber.interrupt *>
ZIO.done(sinkExit).map { case (leftovers, b) => handleSide(leftovers, b, None) },
(scheduleExit, _) =>
ZIO
.done(scheduleExit)
.foldCauseZIO(
_.failureOrCause match {
case Left(_) =>
handoff.offer(End(ScheduleEnd)).forkDaemon *> sinkFiber.join.map { case (leftovers, b) =>
handleSide(leftovers, b, None)
}
case Right(cause) =>
handoff.offer(Halt(cause)).forkDaemon *> sinkFiber.join.map { case (leftovers, b) =>
handleSide(leftovers, b, None)
}
},
c =>
handoff.offer(End(ScheduleEnd)).forkDaemon *>
sinkFiber.join.map { case (leftovers, b) =>
handleSide(leftovers, b, Some(c))
}
)
)
}
}
ZStream.unwrapScopedWith { scope =>
for {
_ <- (self.channel >>> handoffProducer).run.forkIn(scope)
sinkFiber <- (handoffConsumer pipeToOrFail sink.channel).collectElements.run.forkIn(scope)
scheduleFiber <- timeout(None).forkIn(scope)
} yield new ZStream(scheduledAggregator(sinkFiber, scheduleFiber, scope))
}
}
}
/**
* Maps the success values of this stream to the specified constant value.
*/
def as[A2](A2: => A2)(implicit trace: Trace): ZStream[R, E, A2] =
map(_ => A2)
/**
* Fan out the stream, producing a list of streams that have the same elements
* as this stream. The driver stream will only ever advance the `maximumLag`
* chunks before the slowest downstream stream.
*/
def broadcast(n: => Int, maximumLag: => Int)(implicit
trace: Trace
): ZIO[R with Scope, Nothing, Chunk[ZStream[Any, E, A]]] =
self
.broadcastedQueues(n, maximumLag)
.map(_.map(ZStream.fromQueueWithShutdown(_).flattenTake))
/**
* Fan out the stream, producing a dynamic number of streams that have the
* same elements as this stream. The driver stream will only ever advance the
* `maximumLag` chunks before the slowest downstream stream.
*/
def broadcastDynamic(
maximumLag: => Int
)(implicit trace: Trace): ZIO[R with Scope, Nothing, ZStream[Any, E, A]] =
self
.broadcastedQueuesDynamic(maximumLag)
.map(ZStream.scoped(_).flatMap(ZStream.fromQueue(_)).flattenTake)
/**
* Converts the stream to a scoped list of queues. Every value will be
* replicated to every queue with the slowest queue being allowed to buffer
* `maximumLag` chunks before the driver is back pressured.
*
* Queues can unsubscribe from upstream by shutting down.
*/
def broadcastedQueues(
n: => Int,
maximumLag: => Int
)(implicit trace: Trace): ZIO[R with Scope, Nothing, Chunk[Dequeue[Take[E, A]]]] =
for {
hub <- Hub.bounded[Take[E, A]](maximumLag)
queues <- ZIO.collectAll(Chunk.fill(n)(hub.subscribe))
_ <- self.runIntoHubScoped(hub).forkScoped
} yield queues
/**
* Converts the stream to a scoped dynamic amount of queues. Every chunk will
* be replicated to every queue with the slowest queue being allowed to buffer
* `maximumLag` chunks before the driver is back pressured.
*
* Queues can unsubscribe from upstream by shutting down.
*/
def broadcastedQueuesDynamic(
maximumLag: => Int
)(implicit trace: Trace): ZIO[R with Scope, Nothing, ZIO[Scope, Nothing, Dequeue[Take[E, A]]]] =
toHub(maximumLag).map(_.subscribe)
/**
* Allows a faster producer to progress independently of a slower consumer by
* buffering up to `capacity` elements in a queue.
*
* @note
* This combinator destroys the chunking structure. It's recommended to use
* rechunk afterwards.
* @note
* Prefer capacities that are powers of 2 for better performance.
*/
def buffer(capacity: => Int)(implicit trace: Trace): ZStream[R, E, A] = {
val queue = self.toQueueOfElements(capacity)
new ZStream(
ZChannel.unwrapScoped[R] {
queue.map { queue =>
lazy val process: ZChannel[Any, Any, Any, Any, E, Chunk[A], Unit] =
ZChannel.fromZIO {
queue.take
}.flatMap { (exit: Exit[Option[E], A]) =>
exit.foldExit(
Cause
.flipCauseOption(_)
.fold[ZChannel[Any, Any, Any, Any, E, Chunk[A], Unit]](ZChannel.unit)(ZChannel.refailCause),
value => ZChannel.write(Chunk.single(value)) *> process
)
}
process
}
}
)
}
/**
* Allows a faster producer to progress independently of a slower consumer by
* buffering up to `capacity` chunks in a queue.
*
* @note
* Prefer capacities that are powers of 2 for better performance.
*/
def bufferChunks(capacity: => Int)(implicit trace: Trace): ZStream[R, E, A] = {
val queue = self.toQueue(capacity)
new ZStream(
ZChannel.unwrapScoped[R] {
queue.map { queue =>
lazy val process: ZChannel[Any, Any, Any, Any, E, Chunk[A], Unit] =
ZChannel.fromZIO {
queue.take
}.flatMap { (take: Take[E, A]) =>
take.fold(
ZChannel.unit,
error => ZChannel.refailCause(error),
value => ZChannel.write(value) *> process
)
}
process
}
}
)
}
/**
* Allows a faster producer to progress independently of a slower consumer by
* buffering up to `capacity` chunks in a dropping queue.
*
* @note
* Prefer capacities that are powers of 2 for better performance.
*/
def bufferChunksDropping(capacity: => Int)(implicit trace: Trace): ZStream[R, E, A] = {
val queue =
ZIO.acquireRelease(Queue.dropping[(Take[E, A], Promise[Nothing, Unit])](capacity))(_.shutdown)
new ZStream(bufferSignal[R, E, A](queue, self.channel))
}
/**
* Allows a faster producer to progress independently of a slower consumer by
* buffering up to `capacity` chunks in a sliding queue.
*
* @note
* Prefer capacities that are powers of 2 for better performance.
*/
def bufferChunksSliding(capacity: => Int)(implicit trace: Trace): ZStream[R, E, A] = {
val queue =
ZIO.acquireRelease(Queue.sliding[(Take[E, A], Promise[Nothing, Unit])](capacity))(_.shutdown)
new ZStream(bufferSignal[R, E, A](queue, self.channel))
}
/**
* Allows a faster producer to progress independently of a slower consumer by
* buffering up to `capacity` elements in a dropping queue.
*
* @note
* This combinator destroys the chunking structure. It's recommended to use
* rechunk afterwards.
* @note
* Prefer capacities that are powers of 2 for better performance.
*/
def bufferDropping(capacity: => Int)(implicit trace: Trace): ZStream[R, E, A] = {
val queue =
ZIO.acquireRelease(Queue.dropping[(Take[E, A], Promise[Nothing, Unit])](capacity))(_.shutdown)
new ZStream(bufferSignal[R, E, A](queue, self.rechunk(1).channel))
}
/**
* Allows a faster producer to progress independently of a slower consumer by
* buffering up to `capacity` elements in a sliding queue.
*
* @note
* This combinator destroys the chunking structure. It's recommended to use
* rechunk afterwards.
* @note
* Prefer capacities that are powers of 2 for better performance.
*/
def bufferSliding(capacity: => Int)(implicit trace: Trace): ZStream[R, E, A] = {
val queue =
ZIO.acquireRelease(Queue.sliding[(Take[E, A], Promise[Nothing, Unit])](capacity))(_.shutdown)
new ZStream(bufferSignal[R, E, A](queue, self.rechunk(1).channel))
}
private def bufferSignal[R1 <: R, E1 >: E, A1 >: A](
scoped: => ZIO[Scope, Nothing, Queue[(Take[E1, A1], Promise[Nothing, Unit])]],
channel: => ZChannel[R1, Any, Any, Any, E1, Chunk[A1], Any]
)(implicit trace: Trace): ZChannel[R1, Any, Any, Any, E1, Chunk[A1], Unit] = {
def producer(
queue: Queue[(Take[E1, A1], Promise[Nothing, Unit])],
ref: Ref[Promise[Nothing, Unit]]
): ZChannel[R1, E1, Chunk[A1], Any, Nothing, Nothing, Any] = {
def terminate(take: Take[E1, A1]): ZChannel[R1, E1, Chunk[A1], Any, Nothing, Nothing, Any] =
ZChannel.fromZIO {
for {
latch <- ref.get
_ <- latch.await
p <- Promise.make[Nothing, Unit]
_ <- queue.offer((take, p))
_ <- ref.set(p)
_ <- p.await
} yield ()
}
ZChannel.readWithCause[R1, E1, Chunk[A1], Any, Nothing, Nothing, Any](
in =>
ZChannel.fromZIO {
for {
p <- Promise.make[Nothing, Unit]
added <- queue.offer((Take.chunk(in), p))
_ <- ref.set(p).when(added)
} yield ()
} *> producer(queue, ref),
err => terminate(Take.failCause(err)),
_ => terminate(Take.end)
)
}
def consumer(
queue: Queue[(Take[E1, A1], Promise[Nothing, Unit])]
): ZChannel[R1, Any, Any, Any, E1, Chunk[A1], Unit] = {
lazy val process: ZChannel[Any, Any, Any, Any, E1, Chunk[A1], Unit] =
ZChannel.fromZIO(queue.take).flatMap { case (take, promise) =>
ZChannel.fromZIO(promise.succeed(())) *>
take.fold(
ZChannel.unit,
error => ZChannel.refailCause(error),
value => ZChannel.write(value) *> process
)
}
process
}
ZChannel.unwrapScoped[R1] {
for {
queue <- scoped
start <- Promise.make[Nothing, Unit]
_ <- start.succeed(())
ref <- Ref.make(start)
_ <- (channel >>> producer(queue, ref)).runScoped.forkScoped
} yield consumer(queue)
}
}
/**
* Allows a faster producer to progress independently of a slower consumer by
* buffering chunks into an unbounded queue.
*/
def bufferUnbounded(implicit trace: Trace): ZStream[R, E, A] = {
val queue = self.toQueueUnbounded
new ZStream(
ZChannel.unwrapScoped[R] {
queue.map { queue =>
lazy val process: ZChannel[Any, Any, Any, Any, E, Chunk[A], Unit] =
ZChannel.fromZIO {
queue.take
}.flatMap { (take: Take[E, A]) =>
take.fold(
ZChannel.unit,
error => ZChannel.refailCause(error),
value => ZChannel.write(value) *> process
)
}
process
}
}
)
}
/**
* Switches over to the stream produced by the provided function in case this
* one fails with a typed error.
*/
def catchAll[R1 <: R, E2, A1 >: A](
f: E => ZStream[R1, E2, A1]
)(implicit ev: CanFail[E], trace: Trace): ZStream[R1, E2, A1] =
catchAllCause(_.failureOrCause.fold(f, ZStream.failCause(_)))
/**
* Switches over to the stream produced by the provided function in case this
* one fails. Allows recovery from all causes of failure, including
* interruption if the stream is uninterruptible.
*/
def catchAllCause[R1 <: R, E2, A1 >: A](f: Cause[E] => ZStream[R1, E2, A1])(implicit
trace: Trace
): ZStream[R1, E2, A1] =
new ZStream(channel.catchAllCause(f(_).channel))
/**
* Switches over to the stream produced by the provided function in case this
* one fails with some typed error.
*/
def catchSome[R1 <: R, E1 >: E, A1 >: A](pf: PartialFunction[E, ZStream[R1, E1, A1]])(implicit
trace: Trace
): ZStream[R1, E1, A1] =
catchAll(pf.applyOrElse[E, ZStream[R1, E1, A1]](_, ZStream.fail(_)))
/**
* Switches over to the stream produced by the provided function in case this
* one fails with some errors. Allows recovery from all causes of failure,
* including interruption if the stream is uninterruptible.
*/
def catchSomeCause[R1 <: R, E1 >: E, A1 >: A](
pf: PartialFunction[Cause[E], ZStream[R1, E1, A1]]
)(implicit trace: Trace): ZStream[R1, E1, A1] =
catchAllCause(pf.applyOrElse[Cause[E], ZStream[R1, E1, A1]](_, ZStream.failCause(_)))
/**
* Returns a new stream that only emits elements that are not equal to the
* previous element emitted, using natural equality to determine whether two
* elements are equal.
*/
def changes(implicit trace: Trace): ZStream[R, E, A] =
changesWith(_ == _)
/**
* Returns a new stream that only emits elements that are not equal to the
* previous element emitted, using the specified function to determine whether
* two elements are equal.
*/
def changesWith(f: (A, A) => Boolean)(implicit trace: Trace): ZStream[R, E, A] =
self >>> ZPipeline.changesWith(f)
/**
* Returns a new stream that only emits elements that are not equal to the
* previous element emitted, using the specified effectual function to
* determine whether two elements are equal.
*/
def changesWithZIO[R1 <: R, E1 >: E](
f: (A, A) => ZIO[R1, E1, Boolean]
)(implicit trace: Trace): ZStream[R1, E1, A] =
self >>> ZPipeline.changesWithZIO(f)
/**
* Exposes the underlying chunks of the stream as a stream of chunks of
* elements.
*/
def chunks(implicit trace: Trace): ZStream[R, E, Chunk[A]] =
mapChunks(Chunk.single)
/**
* Performs the specified stream transformation with the chunk structure of
* the stream exposed.
*/
def chunksWith[R1, E1, A1](f: ZStream[R, E, Chunk[A]] => ZStream[R1, E1, Chunk[A1]])(implicit
trace: Trace
): ZStream[R1, E1, A1] =
f(self.chunks).flattenChunks
/**
* Performs a filter and map in a single step.
*/
def collect[B](f: PartialFunction[A, B])(implicit trace: Trace): ZStream[R, E, B] =
mapChunks(_.collect(f))
/**
* Filters any `Right` values.
*/
def collectLeft[L1, A1](implicit ev: A <:< Either[L1, A1], trace: Trace): ZStream[R, E, L1] =
self.asInstanceOf[ZStream[R, E, Either[L1, A1]]] >>> ZPipeline.collectLeft
/**
* Filters any 'None' values.
*/
def collectSome[A1](implicit ev: A <:< Option[A1], trace: Trace): ZStream[R, E, A1] =
self.asInstanceOf[ZStream[R, E, Option[A1]]] >>> ZPipeline.collectSome[E, A1]
/**
* Filters any `Exit.Failure` values.
*/
def collectSuccess[L1, A1](implicit ev: A <:< Exit[L1, A1], trace: Trace): ZStream[R, E, A1] =
self.asInstanceOf[ZStream[R, E, Exit[L1, A1]]] >>> ZPipeline.collectSuccess
/**
* Filters any `Left` values.
*/
def collectRight[L1, A1](implicit ev: A <:< Either[L1, A1], trace: Trace): ZStream[R, E, A1] =
self.asInstanceOf[ZStream[R, E, Either[L1, A1]]] >>> ZPipeline.collectRight
/**
* Delays the emission of values by holding new values for a set duration. If
* no new values arrive during that time the value is emitted, however if a
* new value is received during the holding period the previous value is
* discarded and the process is repeated with the new value.
*
* This operator is useful if you have a stream of "bursty" events which
* eventually settle down and you only need the final event of the burst.
*
* @example
* A search engine may only want to initiate a search after a user has
* paused typing so as to not prematurely recommend results.
*/
def debounce(d: => Duration)(implicit trace: Trace): ZStream[R, E, A] = {
import DebounceState._
import HandoffSignal._
ZStream.unwrapScopedWith { scope =>
for {
d <- ZIO.succeed(d)
handoff <- ZStream.Handoff.make[HandoffSignal[E, A]]
} yield {
def enqueue(last: Chunk[A]) =
for {
f <- Clock.sleep(d).as(last).forkIn(scope)
} yield consumer(Previous(f))
lazy val producer: ZChannel[R, E, Chunk[A], Any, E, Nothing, Any] =
ZChannel.readWithCause(
(in: Chunk[A]) =>
in.lastOption.fold(producer) { last =>
ZChannel.fromZIO(handoff.offer(Emit(Chunk.single(last)))) *> producer
},
(cause: Cause[E]) => ZChannel.fromZIO(handoff.offer(Halt(cause))),
(_: Any) => ZChannel.fromZIO(handoff.offer(End(ZStream.SinkEndReason.UpstreamEnd)))
)
def consumer(state: DebounceState[E, A]): ZChannel[R, Any, Any, Any, E, Chunk[A], Any] =
ZChannel.unwrap(
state match {
case NotStarted =>
handoff.take.map {
case HandoffSignal.Emit(last) => ZChannel.unwrap(enqueue(last))
case HandoffSignal.Halt(error) => ZChannel.refailCause(error)
case HandoffSignal.End(_) => ZChannel.unit
}
case Current(fiber) =>
fiber.join.map {
case HandoffSignal.Emit(last) => ZChannel.unwrap(enqueue(last))
case HandoffSignal.Halt(error) => ZChannel.refailCause(error)
case HandoffSignal.End(_) => ZChannel.unit
}
case Previous(fiber) =>
handoff.take.forkIn(scope).flatMap { handoffFib =>
fiber.join
.raceWith[R, E, E, HandoffSignal[E, A], ZChannel[
R,
Any,
Any,
Any,
E,
Chunk[A],
Any
]](
handoffFib.join
)(
{
case (Exit.Success(a), current) =>
current.interrupt *> ZIO.succeed(ZChannel.write(a) *> consumer(Current(handoffFib)))
case (Exit.Failure(cause), current) =>
current.interrupt as ZChannel.refailCause(cause)
},
{
case (Exit.Success(Emit(last)), previous) =>
previous.interrupt *> enqueue(last)
case (Exit.Success(Halt(cause)), previous) =>
previous.interrupt as ZChannel.refailCause(cause)
case (Exit.Success(End(_)), previous) =>
previous.join.map(ZChannel.write(_) *> ZChannel.unit)
case (Exit.Failure(cause), previous) =>
previous.interrupt as ZChannel.refailCause(cause)
}
)
}
}
)
ZStream.scopedWith(scope => (self.channel >>> producer).runIn(scope).forkIn(scope)) *>
new ZStream(consumer(NotStarted))
}
}
}
/**
* Taps the stream, printing the result of calling `.toString` on the emitted
* values.
*/
def debug(implicit trace: Trace): ZStream[R, E, A] =
self
.tap(a => ZIO.debug(a))
.tapErrorCause(e => ZIO.debug(s": $e"))
/**
* Taps the stream, printing the result of calling `.toString` on the emitted
* values. Prefixes the output with the given label.
*/
def debug(label: String)(implicit trace: Trace): ZStream[R, E, A] =
self
.tap(a => ZIO.debug(s"$label: $a"))
.tapErrorCause(e => ZIO.debug(s" $label: $e"))
/**
* Creates a pipeline that groups on adjacent keys, calculated by function f.
*/
def groupAdjacentBy[K](
f: A => K
)(implicit trace: Trace): ZStream[R, E, (K, NonEmptyChunk[A])] =
self >>> ZPipeline.groupAdjacentBy(f)
/**
* Performs an effectful filter and map in a single step.
*/
def collectZIO[R1 <: R, E1 >: E, A1](pf: PartialFunction[A, ZIO[R1, E1, A1]])(implicit
trace: Trace
): ZStream[R1, E1, A1] = {
def loop(chunkIterator: Chunk.ChunkIterator[A], index: Int): ZChannel[R1, E, Chunk[A], Any, E1, Chunk[A1], Any] =
if (chunkIterator.hasNextAt(index))
ZChannel.unwrap {
val a = chunkIterator.nextAt(index)
pf.andThen(_.map(a1 => ZChannel.write(Chunk.single(a1)) *> loop(chunkIterator, index + 1)))
.applyOrElse(a, (_: A) => ZIO.succeed(loop(chunkIterator, index + 1)))
}
else
ZChannel.readWithCause(
elem => loop(elem.chunkIterator, 0),
err => ZChannel.refailCause(err),
done => ZChannel.succeed(done)
)
new ZStream(self.channel >>> loop(Chunk.ChunkIterator.empty, 0))
}
/**
* Transforms all elements of the stream for as long as the specified partial
* function is defined.
*/
def collectWhile[A1](pf: PartialFunction[A, A1])(implicit trace: Trace): ZStream[R, E, A1] =
self >>> ZPipeline.collectWhile(pf)
/**
* Terminates the stream when encountering the first `Right`.
*/
def collectWhileLeft[L1, A1](implicit ev: A <:< Either[L1, A1], trace: Trace): ZStream[R, E, L1] = {
val _ = ev
self.asInstanceOf[ZStream[R, E, Either[L1, A1]]].collectWhile { case Left(a) => a }
}
/**
* Terminates the stream when encountering the first `None`.
*/
def collectWhileSome[A1](implicit ev: A <:< Option[A1], trace: Trace): ZStream[R, E, A1] = {
val _ = ev
self.asInstanceOf[ZStream[R, E, Option[A1]]].collectWhile { case Some(a) => a }
}
/**
* Terminates the stream when encountering the first `Left`.
*/
def collectWhileRight[L1, A1](implicit ev: A <:< Either[L1, A1], trace: Trace): ZStream[R, E, A1] = {
val _ = ev
self.asInstanceOf[ZStream[R, E, Either[L1, A1]]].collectWhile { case Right(a) => a }
}
/**
* Terminates the stream when encountering the first `Exit.Failure`.
*/
def collectWhileSuccess[L1, A1](implicit ev: A <:< Exit[L1, A1], trace: Trace): ZStream[R, E, A1] = {
val _ = ev
self.asInstanceOf[ZStream[R, E, Exit[L1, A1]]].collectWhile { case Exit.Success(a) => a }
}
/**
* Effectfully transforms all elements of the stream for as long as the
* specified partial function is defined.
*/
def collectWhileZIO[R1 <: R, E1 >: E, A1](
pf: PartialFunction[A, ZIO[R1, E1, A1]]
)(implicit trace: Trace): ZStream[R1, E1, A1] =
self >>> ZPipeline.collectWhileZIO(pf)
/**
* Combines the elements from this stream and the specified stream by
* repeatedly applying the function `f` to extract an element using both sides
* and conceptually "offer" it to the destination stream. `f` can maintain
* some internal state to control the combining process, with the initial
* state being specified by `s`.
*
* Where possible, prefer [[ZStream#combineChunks]] for a more efficient
* implementation.
*/
def combine[R1 <: R, E1 >: E, S, A2, A3](that: => ZStream[R1, E1, A2])(s: => S)(
f: (S, ZIO[R, Option[E], A], ZIO[R1, Option[E1], A2]) => ZIO[R1, Nothing, Exit[Option[E1], (A3, S)]]
)(implicit trace: Trace): ZStream[R1, E1, A3] = {
def producer[Err, Elem](
handoff: ZStream.Handoff[Exit[Option[Err], Elem]],
latch: ZStream.Handoff[Unit]
): ZChannel[R1, Err, Elem, Any, Nothing, Nothing, Any] =
ZChannel.fromZIO(latch.take) *>
ZChannel.readWithCause[R1, Err, Elem, Any, Nothing, Nothing, Any](
value => ZChannel.fromZIO(handoff.offer(Exit.succeed(value))) *> producer(handoff, latch),
cause => ZChannel.fromZIO(handoff.offer(Exit.failCause(cause.map(Some(_))))),
_ => ZChannel.fromZIO(handoff.offer(Exit.failNone)) *> producer(handoff, latch)
)
new ZStream(
ZChannel.unwrapScopedWith { scope =>
for {
left <- ZStream.Handoff.make[Exit[Option[E], A]]
right <- ZStream.Handoff.make[Exit[Option[E1], A2]]
latchL <- ZStream.Handoff.make[Unit]
latchR <- ZStream.Handoff.make[Unit]
_ <- (self.channel.concatMap(ZChannel.writeChunk(_)) >>> producer(left, latchL)).runIn(scope).forkIn(scope)
_ <- (that.channel.concatMap(ZChannel.writeChunk(_)) >>> producer(right, latchR)).runIn(scope).forkIn(scope)
pullLeft = latchL.offer(()) *> left.take.flatMap(ZIO.done(_))
pullRight = latchR.offer(()) *> right.take.flatMap(ZIO.done(_))
} yield ZStream.unfoldZIO(s)(s => f(s, pullLeft, pullRight).flatMap(ZIO.done(_).unsome)).channel
}
)
}
/**
* Combines the chunks from this stream and the specified stream by repeatedly
* applying the function `f` to extract a chunk using both sides and
* conceptually "offer" it to the destination stream. `f` can maintain some
* internal state to control the combining process, with the initial state
* being specified by `s`.
*/
def combineChunks[R1 <: R, E1 >: E, S, A2, A3](that: => ZStream[R1, E1, A2])(s: => S)(
f: (
S,
ZIO[R, Option[E], Chunk[A]],
ZIO[R1, Option[E1], Chunk[A2]]
) => ZIO[R1, Nothing, Exit[Option[E1], (Chunk[A3], S)]]
)(implicit trace: Trace): ZStream[R1, E1, A3] = {
def producer[Err, Elem](
handoff: ZStream.Handoff[Take[Err, Elem]],
latch: ZStream.Handoff[Unit]
): ZChannel[R1, Err, Chunk[Elem], Any, Nothing, Nothing, Any] =
ZChannel.fromZIO(latch.take) *>
ZChannel.readWithCause[R1, Err, Chunk[Elem], Any, Nothing, Nothing, Any](
chunk => ZChannel.fromZIO(handoff.offer(Take.chunk(chunk))) *> producer(handoff, latch),
cause => ZChannel.fromZIO(handoff.offer(Take.failCause(cause))),
_ => ZChannel.fromZIO(handoff.offer(Take.end))
)
new ZStream(
ZChannel.unwrapScopedWith { scope =>
for {
left <- ZStream.Handoff.make[Take[E, A]]
right <- ZStream.Handoff.make[Take[E1, A2]]
latchL <- ZStream.Handoff.make[Unit]
latchR <- ZStream.Handoff.make[Unit]
_ <- (self.channel >>> producer(left, latchL)).runIn(scope).forkIn(scope)
_ <- (that.channel >>> producer(right, latchR)).runIn(scope).forkIn(scope)
pullLeft = latchL.offer(()) *> left.take.flatMap(_.done)
pullRight = latchR.offer(()) *> right.take.flatMap(_.done)
} yield ZStream.unfoldChunkZIO(s)(s => f(s, pullLeft, pullRight).flatMap(ZIO.done(_).unsome)).channel
}
)
}
/**
* Concatenates the specified stream with this stream, resulting in a stream
* that emits the elements from this stream and then the elements from the
* specified stream.
*/
def concat[R1 <: R, E1 >: E, A1 >: A](that: => ZStream[R1, E1, A1])(implicit
trace: Trace
): ZStream[R1, E1, A1] =
new ZStream(channel *> that.channel)
/**
* Composes this stream with the specified stream to create a cartesian
* product of elements. The `that` stream would be run multiple times, for
* every element in the `this` stream.
*
* See also [[ZStream#zip]] and [[ZStream#<&>]] for the more common point-wise
* variant.
*/
def cross[R1 <: R, E1 >: E, B](that: => ZStream[R1, E1, B])(implicit
zippable: Zippable[A, B],
trace: Trace
): ZStream[R1, E1, zippable.Out] =
crossWith(that)((a, b) => zippable.zip(a, b))
/**
* Composes this stream with the specified stream to create a cartesian
* product of elements, but keeps only elements from this stream. The `that`
* stream would be run multiple times, for every element in the `this` stream.
*
* See also [[ZStream#zip]] and [[ZStream#<&>]] for the more common point-wise
* variant.
*/
def crossLeft[R1 <: R, E1 >: E, B](that: => ZStream[R1, E1, B])(implicit
trace: Trace
): ZStream[R1, E1, A] =
crossWith(that)((a, _) => a)
/**
* Composes this stream with the specified stream to create a cartesian
* product of elements, but keeps only elements from the other stream. The
* `that` stream would be run multiple times, for every element in the `this`
* stream.
*
* See also [[ZStream#zip]] and [[ZStream#<&>]] for the more common point-wise
* variant.
*/
def crossRight[R1 <: R, E1 >: E, B](that: => ZStream[R1, E1, B])(implicit trace: Trace): ZStream[R1, E1, B] =
self.flatMap(_ => that)
/**
* Composes this stream with the specified stream to create a cartesian
* product of elements with a specified function. The `that` stream would be
* run multiple times, for every element in the `this` stream.
*
* See also [[ZStream#zip]] and [[ZStream#<&>]] for the more common point-wise
* variant.
*/
def crossWith[R1 <: R, E1 >: E, A2, C](that: => ZStream[R1, E1, A2])(f: (A, A2) => C)(implicit
trace: Trace
): ZStream[R1, E1, C] =
self.flatMap(l => that.map(r => f(l, r)))
/**
* More powerful version of `ZStream#broadcast`. Allows to provide a function
* that determines what queues should receive which elements. The decide
* function will receive the indices of the queues in the resulting list.
*/
def distributedWith[E1 >: E](
n: => Int,
maximumLag: => Int,
decide: A => UIO[Int => Boolean]
)(implicit trace: Trace): ZIO[R with Scope, Nothing, List[Dequeue[Exit[Option[E1], A]]]] =
Promise.make[Nothing, A => UIO[UniqueKey => Boolean]].flatMap { prom =>
distributedWithDynamic(maximumLag, (a: A) => prom.await.flatMap(_(a)), _ => ZIO.unit).flatMap { next =>
ZIO.collectAll {
Range(0, n).map(id => next.map { case (key, queue) => ((key -> id), queue) })
}.flatMap { entries =>
val (mappings, queues) =
entries.foldRight((Map.empty[UniqueKey, Int], List.empty[Dequeue[Exit[Option[E1], A]]])) {
case ((mapping, queue), (mappings, queues)) =>
(mappings + mapping, queue :: queues)
}
prom.succeed((a: A) => decide(a).map(f => (key: UniqueKey) => f(mappings(key)))).as(queues)
}
}
}
/**
* More powerful version of `ZStream#distributedWith`. This returns a function
* that will produce new queues and corresponding indices. You can also
* provide a function that will be executed after the final events are
* enqueued in all queues. Shutdown of the queues is handled by the driver.
* Downstream users can also shutdown queues manually. In this case the driver
* will continue but no longer backpressure on them.
*/
def distributedWithDynamic(
maximumLag: => Int,
decide: A => UIO[UniqueKey => Boolean],
done: Exit[Option[E], Nothing] => UIO[Any] = (_: Any) => ZIO.unit
)(implicit trace: Trace): ZIO[R with Scope, Nothing, UIO[(UniqueKey, Dequeue[Exit[Option[E], A]])]] =
for {
queuesRef <- ZIO.acquireReleaseExit(Ref.make[Map[UniqueKey, Queue[Exit[Option[E], A]]]](Map()))((map, exit) =>
map.get.flatMap(qs => ZIO.foreach(qs.values)(_.shutdown))
)
add <- {
val offer = (a: A) =>
for {
shouldProcess <- decide(a)
queues <- queuesRef.get
_ <- ZIO
.foldLeft(queues)(List[UniqueKey]()) { case (acc, (id, queue)) =>
if (shouldProcess(id)) {
queue
.offer(Exit.succeed(a))
.foldCauseZIO(
{
// we ignore all downstream queues that were shut down and remove them later
case c if c.isInterrupted => ZIO.succeed(id :: acc)
case c => Exit.failCause(c)
},
_ => ZIO.succeed(acc)
)
} else ZIO.succeed(acc)
}
.flatMap(ids => if (ids.nonEmpty) queuesRef.update(_ -- ids) else ZIO.unit)
} yield ()
for {
queuesLock <- Semaphore.make(1)
newQueue <- Ref
.make[UIO[(UniqueKey, Queue[Exit[Option[E], A]])]] {
for {
queue <- Queue.bounded[Exit[Option[E], A]](maximumLag)
id = UniqueKey()
_ <- queuesRef.update(_.updated(id, queue))
} yield (id, queue)
}
finalize = (endTake: Exit[Option[E], Nothing]) =>
// we need to make sure that no queues are currently being added
queuesLock.withPermit {
for {
// all newly created queues should end immediately
_ <- newQueue.set {
for {
queue <- Queue.bounded[Exit[Option[E], A]](1)
_ <- queue.offer(endTake)
id = UniqueKey()
_ <- queuesRef.update(_.updated(id, queue))
} yield (id, queue)
}
queues <- queuesRef.get.map(_.values)
_ <- ZIO.foreach(queues) { queue =>
queue.offer(endTake).catchSomeCause {
case c if c.isInterrupted => ZIO.unit
}
}
_ <- done(endTake)
} yield ()
}
_ <- self
.runForeachScoped(offer)
.foldCauseZIO(
cause => finalize(Exit.failCause(cause.map(Some(_)))),
_ => finalize(Exit.failNone)
)
.forkScoped
} yield queuesLock.withPermit(newQueue.get.flatten)
}
} yield add
/**
* Converts this stream to a stream that executes its effects but emits no
* elements. Useful for sequencing effects using streams:
*
* {{{
* (Stream(1, 2, 3).tap(i => ZIO(println(i))) ++
* Stream.fromZIO(ZIO(println("Done!"))).drain ++
* Stream(4, 5, 6).tap(i => ZIO(println(i)))).run(Sink.drain)
* }}}
*/
def drain(implicit trace: Trace): ZStream[R, E, Nothing] =
new ZStream(channel.drain)
/**
* Drains the provided stream in the background for as long as this stream is
* running. If this stream ends before `other`, `other` will be interrupted.
* If `other` fails, this stream will fail with that error.
*/
def drainFork[R1 <: R, E1 >: E](
other: => ZStream[R1, E1, Any]
)(implicit trace: Trace): ZStream[R1, E1, A] =
ZStream.fromZIO(Promise.make[E1, Nothing]).flatMap { bgDied =>
ZStream
.scopedWith(scope => other.channel.drain.runIn(scope).catchAllCause(bgDied.failCause(_)).forkIn(scope)) *>
self.interruptWhen(bgDied)
}
/**
* Drops the specified number of elements from this stream.
*/
def drop(n: => Int)(implicit trace: Trace): ZStream[R, E, A] =
self >>> ZPipeline.drop(n)
/**
* Drops the last specified number of elements from this stream.
*
* @note
* This combinator keeps `n` elements in memory. Be careful with big
* numbers.
*/
def dropRight(n: => Int)(implicit trace: Trace): ZStream[R, E, A] =
self >>> ZPipeline.dropRight(n)
/**
* Drops all elements of the stream for as long as the specified predicate
* evaluates to `true`.
*/
def dropWhile(f: A => Boolean)(implicit trace: Trace): ZStream[R, E, A] =
self >>> ZPipeline.dropWhile(f)
/**
* Drops all elements of the stream until the specified predicate evaluates to
* `true`.
*/
def dropUntil(pred: A => Boolean)(implicit trace: Trace): ZStream[R, E, A] =
self >>> ZPipeline.dropUntil(pred)
/**
* Drops all elements of the stream for as long as the specified predicate
* produces an effect that evalutates to `true`
*
* @see
* [[dropWhile]]
*/
def dropWhileZIO[R1 <: R, E1 >: E](f: A => ZIO[R1, E1, Boolean])(implicit
trace: Trace
): ZStream[R1, E1, A] =
pipeThrough(ZSink.dropWhileZIO[R1, E1, A](f))
/**
* Returns a stream whose failures and successes have been lifted into an
* `Either`. The resulting stream cannot fail, because the failures have been
* exposed as part of the `Either` success case.
*
* @note
* the stream will end as soon as the first error occurs.
*/
def either(implicit ev: CanFail[E], trace: Trace): ZStream[R, Nothing, Either[E, A]] =
self.map(Right(_)).catchAll(e => ZStream(Left(e)))
/**
* Executes the provided finalizer after this stream's finalizers run.
*/
def ensuring[R1 <: R](fin: => ZIO[R1, Nothing, Any])(implicit trace: Trace): ZStream[R1, E, A] =
new ZStream(channel.ensuring(fin))
/**
* Executes the provided finalizer after this stream's finalizers run.
*/
def ensuringWith[R1 <: R](fin: Exit[E, Any] => ZIO[R1, Nothing, Any])(implicit trace: Trace): ZStream[R1, E, A] =
new ZStream(channel.ensuringWith(fin))
/**
* Filters the elements emitted by this stream using the provided function.
*/
def filter(f: A => Boolean)(implicit trace: Trace): ZStream[R, E, A] =
mapChunks(_.filter(f))
/**
* Finds the first element emitted by this stream that satisfies the provided
* predicate.
*/
def find(f: A => Boolean)(implicit trace: Trace): ZStream[R, E, A] = {
lazy val loop: ZChannel[R, E, Chunk[A], Any, E, Chunk[A], Any] =
ZChannel.readWithCause(
(in: Chunk[A]) => in.find(f).fold(loop)(i => ZChannel.write(Chunk.single(i))),
(e: Cause[E]) => ZChannel.refailCause(e),
(_: Any) => ZChannel.unit
)
new ZStream(self.channel >>> loop)
}
/**
* Finds the first element emitted by this stream that satisfies the provided
* effectful predicate.
*/
def findZIO[R1 <: R, E1 >: E, S](
f: A => ZIO[R1, E1, Boolean]
)(implicit trace: Trace): ZStream[R1, E1, A] = {
lazy val loop: ZChannel[R1, E, Chunk[A], Any, E1, Chunk[A], Any] =
ZChannel.readWithCause(
(in: Chunk[A]) => ZChannel.unwrap(in.findZIO(f).map(_.fold(loop)(i => ZChannel.write(Chunk.single(i))))),
(e: Cause[E]) => ZChannel.refailCause(e),
(_: Any) => ZChannel.unit
)
new ZStream(self.channel >>> loop)
}
/**
* Consumes all elements of the stream, passing them to the specified
* callback.
*/
def foreach[R1 <: R, E1 >: E](f: A => ZIO[R1, E1, Any])(implicit trace: Trace): ZIO[R1, E1, Unit] =
runForeach(f)
/**
* Repeats this stream forever.
*/
def forever(implicit trace: Trace): ZStream[R, E, A] =
new ZStream(channel.repeated)
/**
* Effectfully filters the elements emitted by this stream.
*/
def filterZIO[R1 <: R, E1 >: E](f: A => ZIO[R1, E1, Boolean])(implicit trace: Trace): ZStream[R1, E1, A] = {
def loop(chunkIterator: Chunk.ChunkIterator[A], index: Int): ZChannel[R1, E, Chunk[A], Any, E1, Chunk[A], Any] =
if (chunkIterator.hasNextAt(index))
ZChannel.unwrap {
val a = chunkIterator.nextAt(index)
f(a).map { b =>
if (b) ZChannel.write(Chunk.single(a)) *> loop(chunkIterator, index + 1)
else loop(chunkIterator, index + 1)
}
}
else
ZChannel.readWithCause(
elem => loop(elem.chunkIterator, 0),
err => ZChannel.refailCause(err),
done => ZChannel.succeed(done)
)
new ZStream(self.channel >>> loop(Chunk.ChunkIterator.empty, 0))
}
/**
* Filters this stream by the specified predicate, removing all elements for
* which the predicate evaluates to true.
*/
def filterNot(pred: A => Boolean)(implicit trace: Trace): ZStream[R, E, A] = filter(a => !pred(a))
/**
* Returns a stream made of the concatenation in strict order of all the
* streams produced by passing each element of this stream to `f0`
*/
def flatMap[R1 <: R, E1 >: E, B](f: A => ZStream[R1, E1, B])(implicit
trace: Trace
): ZStream[R1, E1, B] =
new ZStream(
channel.concatMap(as =>
as.foldLeft[ZChannel[R1, Any, Any, Any, E1, zio.Chunk[B], Any]](ZChannel.unit) { case (acc, a) =>
acc *> f(a).channel
}
)
)
/**
* Maps each element of this stream to another stream and returns the
* non-deterministic merge of those streams, executing up to `n` inner streams
* concurrently. Up to `bufferSize` elements of the produced streams may be
* buffered in memory by this operator.
*/
def flatMapPar[R1 <: R, E1 >: E, B](n: => Int, bufferSize: => Int = 16)(
f: A => ZStream[R1, E1, B]
)(implicit trace: Trace): ZStream[R1, E1, B] =
new ZStream[R1, E1, B](
channel.concatMap(ZChannel.writeChunk(_)).mergeMap[R1, Any, Any, Any, E1, Chunk[B]](n, bufferSize) {
f(_).channel
}
)
/**
* Maps each element of this stream to another stream and returns the
* non-deterministic merge of those streams, executing up to `n` inner streams
* concurrently. When a new stream is created from an element of the source
* stream, the oldest executing stream is cancelled. Up to `bufferSize`
* elements of the produced streams may be buffered in memory by this
* operator.
*/
def flatMapParSwitch[R1 <: R, E1 >: E, B](n: => Int, bufferSize: => Int = 16)(
f: A => ZStream[R1, E1, B]
)(implicit trace: Trace): ZStream[R1, E1, B] =
new ZStream[R1, E1, B](
channel
.concatMap(ZChannel.writeChunk(_))
.mergeMap[R1, Any, Any, Any, E1, Chunk[B]](n, bufferSize, ZChannel.MergeStrategy.BufferSliding) {
f(_).channel
}
)
/**
* Flattens this stream-of-streams into a stream made of the concatenation in
* strict order of all the streams.
*/
def flatten[R1 <: R, E1 >: E, A1](implicit ev: A <:< ZStream[R1, E1, A1], trace: Trace): ZStream[R1, E1, A1] =
flatMap(ev(_))
/**
* Submerges the chunks carried by this stream into the stream's structure,
* while still preserving them.
*/
def flattenChunks[A1](implicit ev: A <:< Chunk[A1], trace: Trace): ZStream[R, E, A1] = {
lazy val flatten: ZChannel[Any, E, Chunk[Chunk[A1]], Any, E, Chunk[A1], Any] =
ZChannel.readWithCause(
chunks => ZChannel.writeChunk(chunks) *> flatten,
cause => ZChannel.refailCause(cause),
_ => ZChannel.unit
)
new ZStream(self.asInstanceOf[ZStream[R, E, Chunk[A1]]].channel >>> flatten)
}
/**
* Flattens [[Exit]] values. `Exit.Failure` values translate to stream
* failures while `Exit.Success` values translate to stream elements.
*/
def flattenExit[E1 >: E, A1](implicit ev: A <:< Exit[E1, A1], trace: Trace): ZStream[R, E1, A1] =
mapZIO(a => ZIO.done(ev(a)))
/**
* Unwraps [[Exit]] values that also signify end-of-stream by failing with
* `None`.
*
* For `Exit[E, A]` values that do not signal end-of-stream, prefer:
* {{{
* stream.mapZIO(ZIO.done(_))
* }}}
*/
def flattenExitOption[E1 >: E, A1](implicit
ev: A <:< Exit[Option[E1], A1],
trace: Trace
): ZStream[R, E1, A1] = {
def processChunk(
chunk: Chunk[Exit[Option[E1], A1]],
cont: ZChannel[R, E, Chunk[Exit[Option[E1], A1]], Any, E1, Chunk[A1], Any]
): ZChannel[R, E, Chunk[Exit[Option[E1], A1]], Any, E1, Chunk[A1], Any] = {
val (toEmit, rest) = chunk.splitWhere(!_.isSuccess)
val next = rest.headOption match {
case Some(Exit.Success(_)) => ZChannel.unit
case Some(Exit.Failure(cause)) =>
Cause.flipCauseOption(cause) match {
case Some(cause) => ZChannel.refailCause(cause)
case None => ZChannel.unit
}
case None => cont
}
ZChannel.write(toEmit.collect { case Exit.Success(a) => a }) *> next
}
lazy val process: ZChannel[R, E, Chunk[Exit[Option[E1], A1]], Any, E1, Chunk[A1], Any] =
ZChannel.readWithCause[R, E, Chunk[Exit[Option[E1], A1]], Any, E1, Chunk[A1], Any](
chunk => processChunk(chunk, process),
cause => ZChannel.refailCause(cause),
_ => ZChannel.unit
)
new ZStream(channel.asInstanceOf[ZChannel[R, Any, Any, Any, E, Chunk[Exit[Option[E1], A1]], Any]] >>> process)
}
/**
* Submerges the iterables carried by this stream into the stream's structure,
* while still preserving them.
*/
def flattenIterables[A1](implicit ev: A <:< Iterable[A1], trace: Trace): ZStream[R, E, A1] =
map(a => Chunk.fromIterable(ev(a))).flattenChunks
/**
* Flattens a stream of streams into a stream by executing a non-deterministic
* concurrent merge. Up to `n` streams may be consumed in parallel and up to
* `outputBuffer` elements may be buffered by this operator.
*/
def flattenPar[R1 <: R, E1 >: E, A1](n: => Int, outputBuffer: => Int = 16)(implicit
ev: A <:< ZStream[R1, E1, A1],
trace: Trace
): ZStream[R1, E1, A1] =
flatMapPar[R1, E1, A1](n, outputBuffer)(ev(_))
/**
* Like [[flattenPar]], but executes all streams concurrently.
*/
def flattenParUnbounded[R1 <: R, E1 >: E, A1](
outputBuffer: => Int = 16
)(implicit ev: A <:< ZStream[R1, E1, A1], trace: Trace): ZStream[R1, E1, A1] =
flattenPar[R1, E1, A1](Int.MaxValue, outputBuffer)
/**
* Unwraps [[Exit]] values and flatten chunks that also signify end-of-stream
* by failing with `None`.
*/
def flattenTake[E1 >: E, A1](implicit ev: A <:< Take[E1, A1], trace: Trace): ZStream[R, E1, A1] =
self.asInstanceOf[ZStream[R, E, Take[E1, A1]]] >>> ZPipeline.flattenTake
def flattenZIO[R1 <: R, E1 >: E, A1](implicit ev: A <:< ZIO[R1, E1, A1], trace: Trace): ZStream[R1, E1, A1] =
mapZIO(ev)
/**
* More powerful version of [[ZStream.groupByKey]]
*/
def groupBy[R1 <: R, E1 >: E, K, V](
f: A => ZIO[R1, E1, (K, V)],
buffer: => Int = 16
): ZStream.GroupBy[R1, E1, K, V] =
new ZStream.GroupBy[R1, E1, K, V] {
def grouped(implicit trace: Trace): ZStream[R1, E1, (K, Dequeue[Take[E1, V]])] =
ZStream.unwrapScoped[R1] {
for {
decider <- Promise.make[Nothing, (K, V) => UIO[UniqueKey => Boolean]]
out <-
ZIO.acquireRelease(Queue.bounded[Exit[Option[E1], (K, Dequeue[Take[E1, V]])]](buffer))(_.shutdown)
ref <- Ref.make[Map[K, UniqueKey]](Map())
add <- self
.mapZIO(f)
.distributedWithDynamic(
buffer,
(kv: (K, V)) => decider.await.flatMap(_.tupled(kv)),
out.offer
)
_ <- decider.succeed { case (k, _) =>
ref.get.map(_.get(k)).flatMap {
case Some(idx) => ZIO.succeed(_ == idx)
case None =>
add.flatMap { case (idx, q) =>
(ref.update(_.updated(k, idx)) *>
out.offer(
Exit.succeed(
k -> ZStream.mapDequeue(q)(exit =>
Take(exit.mapExit { case (_, value) => Chunk.single(value) })
)
)
)).as(_ == idx)
}
}
}
} yield ZStream.fromQueueWithShutdown(out).flattenExitOption
}
}
/**
* Partition a stream using a function and process each stream individually.
* This returns a data structure that can be used to further filter down which
* groups shall be processed.
*
* After calling apply on the GroupBy object, the remaining groups will be
* processed in parallel and the resulting streams merged in a
* nondeterministic fashion.
*
* Up to `buffer` elements may be buffered in any group stream before the
* producer is backpressured. Take care to consume from all streams in order
* to prevent deadlocks.
*
* Example: Collect the first 2 words for every starting letter from a stream
* of words.
* {{{
* ZStream.fromIterable(List("hello", "world", "hi", "holla"))
* .groupByKey(_.head) { case (k, s) => s.take(2).map((k, _)) }
* .runCollect
* .map(_ == List(('h', "hello"), ('h', "hi"), ('w', "world"))
* }}}
*/
def groupByKey[K](
f: A => K,
buffer: => Int = 16
): ZStream.GroupBy[R, E, K, A] =
new ZStream.GroupBy[R, E, K, A] {
def grouped(implicit trace: Trace): ZStream[R, E, (K, Dequeue[Take[E, A]])] = {
def groupByKey(
map: mutable.Map[K, Queue[Take[E, A]]],
outerQueue: Queue[Take[E, (K, Queue[Take[E, A]])]]
): ZChannel[R, E, Chunk[A], Any, E, Any, Any] =
ZChannel.readWithCause(
in =>
ZChannel.fromZIO {
ZIO.foreachDiscard(ZStream.groupBy(in)(f)) { case (key, values) =>
map.get(key) match {
case Some(innerQueue) =>
innerQueue.offer(Take.chunk(values)).catchSomeCause {
case cause if cause.isInterruptedOnly => ZIO.unit
}
case None =>
Queue.bounded[Take[E, A]](buffer).flatMap { innerQueue =>
ZIO.succeed(map += key -> innerQueue) *>
outerQueue.offer(Take.single(key -> innerQueue)) *>
innerQueue.offer(Take.chunk(values)).catchSomeCause {
case cause if cause.isInterruptedOnly => ZIO.unit
}
}
}
}
} *> groupByKey(map, outerQueue),
e => ZChannel.fromZIO(outerQueue.offer(Take.failCause(e))),
_ =>
ZChannel.fromZIO {
ZIO.foreachDiscard(map) { case (_, innerQueue) =>
innerQueue.offer(Take.end).catchSomeCause { case cause if cause.isInterruptedOnly => ZIO.unit }
} *> outerQueue.offer(Take.end)
}
)
ZStream.unwrapScopedWith { scope =>
for {
map <- ZIO.succeed(mutable.Map.empty[K, Queue[Take[E, A]]])
queue <- Queue.unbounded[Take[E, (K, Queue[Take[E, A]])]]
_ <- scope.addFinalizer(queue.shutdown)
_ <- (self.channel >>> groupByKey(map, queue)).drain.runIn(scope).forkIn(scope)
} yield ZStream.fromQueueWithShutdown(queue).flattenTake
}
}
}
/**
* Partitions the stream with specified chunkSize
* @param chunkSize
* size of the chunk
*/
def grouped(chunkSize: => Int)(implicit trace: Trace): ZStream[R, E, Chunk[A]] =
self >>> ZPipeline.grouped(chunkSize)
/**
* Partitions the stream with the specified chunkSize or until the specified
* duration has passed, whichever is satisfied first.
*/
def groupedWithin(chunkSize: => Int, within: => Duration)(implicit
trace: Trace
): ZStream[R, E, Chunk[A]] =
aggregateAsyncWithin(ZSink.collectAllN[A](chunkSize), Schedule.spaced(within))
/**
* Halts the evaluation of this stream when the provided IO completes. The
* given IO will be forked as part of the returned stream, and its success
* will be discarded.
*
* An element in the process of being pulled will not be interrupted when the
* IO completes. See `interruptWhen` for this behavior.
*
* If the IO completes with a failure, the stream will emit that failure.
*/
def haltWhen[R1 <: R, E1 >: E](io: ZIO[R1, E1, Any])(implicit trace: Trace): ZStream[R1, E1, A] = {
def writer(fiber: Fiber[E1, Any]): ZChannel[R1, E1, Chunk[A], Any, E1, Chunk[A], Unit] =
ZChannel.unwrap {
fiber.poll.map {
case None =>
ZChannel.readWith[R1, E1, Chunk[A], Any, E1, Chunk[A], Unit](
in => ZChannel.write(in) *> writer(fiber),
err => ZChannel.fail(err),
_ => ZChannel.unit
)
case Some(exit) =>
exit.foldExit(ZChannel.refailCause, _ => ZChannel.unit)
}
}
new ZStream(
ZChannel.unwrapScopedWith { scope =>
io.forkIn(scope).map { fiber =>
self.channel >>> writer(fiber)
}
}
)
}
/**
* Specialized version of haltWhen which halts the evaluation of this stream
* after the given duration.
*
* An element in the process of being pulled will not be interrupted when the
* given duration completes. See `interruptAfter` for this behavior.
*/
def haltAfter(duration: => Duration)(implicit trace: Trace): ZStream[R, E, A] =
haltWhen(Clock.sleep(duration))
/**
* Halts the evaluation of this stream when the provided promise resolves.
*
* If the promise completes with a failure, the stream will emit that failure.
*/
def haltWhen[E1 >: E](p: Promise[E1, _])(implicit trace: Trace): ZStream[R, E1, A] = {
lazy val writer: ZChannel[R, E1, Chunk[A], Any, E1, Chunk[A], Unit] =
ZChannel.unwrap {
p.poll.map {
case None =>
ZChannel.readWith[R, E1, Chunk[A], Any, E1, Chunk[A], Unit](
in => ZChannel.write(in) *> writer,
err => ZChannel.fail(err),
_ => ZChannel.unit
)
case Some(io) =>
ZChannel.unwrap(io.fold(ZChannel.fail(_), _ => ZChannel.unit))
}
}
new ZStream(self.channel >>> writer)
}
/**
* Interleaves this stream and the specified stream deterministically by
* alternating pulling values from this stream and the specified stream. When
* one stream is exhausted all remaining values in the other stream will be
* pulled.
*/
def interleave[R1 <: R, E1 >: E, A1 >: A](that: => ZStream[R1, E1, A1])(implicit
trace: Trace
): ZStream[R1, E1, A1] =
self.interleaveWith(that)(ZStream(true, false).forever)
/**
* Combines this stream and the specified stream deterministically using the
* stream of boolean values `b` to control which stream to pull from next.
* `true` indicates to pull from this stream and `false` indicates to pull
* from the specified stream. Only consumes as many elements as requested by
* `b`. If either this stream or the specified stream are exhausted further
* requests for values from that stream will be ignored.
*/
def interleaveWith[R1 <: R, E1 >: E, A1 >: A](
that: => ZStream[R1, E1, A1]
)(b: => ZStream[R1, E1, Boolean])(implicit trace: Trace): ZStream[R1, E1, A1] = {
def producer(handoff: ZStream.Handoff[Take[E1, A1]]): ZChannel[R1, E1, A1, Any, Nothing, Nothing, Unit] =
ZChannel.readWithCause[R1, E1, A1, Any, Nothing, Nothing, Unit](
value => ZChannel.fromZIO(handoff.offer(Take.single(value))) *> producer(handoff),
cause => ZChannel.fromZIO(handoff.offer(Take.failCause(cause))),
_ => ZChannel.fromZIO(handoff.offer(Take.end))
)
new ZStream(
ZChannel.unwrapScopedWith { scope =>
for {
left <- ZStream.Handoff.make[Take[E1, A1]]
right <- ZStream.Handoff.make[Take[E1, A1]]
_ <- (self.channel.concatMap(ZChannel.writeChunk(_)) >>> producer(left)).runIn(scope).forkIn(scope)
_ <- (that.channel.concatMap(ZChannel.writeChunk(_)) >>> producer(right)).runIn(scope).forkIn(scope)
} yield {
def process(leftDone: Boolean, rightDone: Boolean): ZChannel[R1, E1, Boolean, Any, E1, Chunk[A1], Unit] =
ZChannel.readWithCause[R1, E1, Boolean, Any, E1, Chunk[A1], Unit](
bool =>
(bool, leftDone, rightDone) match {
case (true, false, _) =>
ZChannel.fromZIO(left.take).flatMap { take =>
take.fold(
if (rightDone) ZChannel.unit else process(true, rightDone),
cause => ZChannel.refailCause(cause),
chunk => ZChannel.write(chunk) *> process(leftDone, rightDone)
)
}
case (false, _, false) =>
ZChannel.fromZIO(right.take).flatMap { take =>
take.fold(
if (leftDone) ZChannel.unit else process(leftDone, true),
cause => ZChannel.refailCause(cause),
chunk => ZChannel.write(chunk) *> process(leftDone, rightDone)
)
}
case _ =>
process(leftDone, rightDone)
},
cause => ZChannel.refailCause(cause),
_ => ZChannel.unit
)
b.channel.concatMap(ZChannel.writeChunk(_)) >>> process(false, false)
}
}
)
}
/**
* Intersperse stream with provided element similar to
* List.mkString.
*/
def intersperse[A1 >: A](middle: => A1)(implicit trace: Trace): ZStream[R, E, A1] =
self >>> ZPipeline.intersperse(middle)
/**
* Intersperse and also add a prefix and a suffix
*/
def intersperse[A1 >: A](start: => A1, middle: => A1, end: => A1)(implicit
trace: Trace
): ZStream[R, E, A1] =
ZStream(start) ++ intersperse(middle) ++ ZStream(end)
/**
* Interrupts the evaluation of this stream when the provided IO completes.
* The given IO will be forked as part of this stream, and its success will be
* discarded. This combinator will also interrupt any in-progress element
* being pulled from upstream.
*
* If the IO completes with a failure before the stream completes, the
* returned stream will emit that failure.
*/
def interruptWhen[R1 <: R, E1 >: E](io: ZIO[R1, E1, Any])(implicit trace: Trace): ZStream[R1, E1, A] =
new ZStream(channel.interruptWhen(io))
/**
* Interrupts the evaluation of this stream when the provided promise
* resolves. This combinator will also interrupt any in-progress element being
* pulled from upstream.
*
* If the promise completes with a failure, the stream will emit that failure.
*/
def interruptWhen[E1 >: E](p: Promise[E1, _])(implicit trace: Trace): ZStream[R, E1, A] =
new ZStream(channel.interruptWhen(p.asInstanceOf[Promise[E1, Any]]))
/**
* Specialized version of interruptWhen which interrupts the evaluation of
* this stream after the given duration.
*/
def interruptAfter(duration: => Duration)(implicit trace: Trace): ZStream[R, E, A] =
interruptWhen(Clock.sleep(duration))
/**
* Returns a combined string resulting from concatenating each of the values
* from the stream
*/
def mkString(implicit trace: Trace): ZIO[R, E, String] =
run(ZSink.mkString)
/**
* Returns a combined string resulting from concatenating each of the values
* from the stream beginning with `before` interspersed with `middle` and
* ending with `after`.
*/
def mkString(before: => String, middle: => String, after: => String)(implicit
trace: Trace
): ZIO[R, E, String] =
intersperse(before, middle, after).mkString
/**
* Transforms the elements of this stream using the supplied function.
*/
def map[B](f: A => B)(implicit trace: Trace): ZStream[R, E, B] =
new ZStream(channel.mapOut(_.map(f)))
/**
* Statefully maps over the elements of this stream to produce new elements.
*/
def mapAccum[S, A1](s: => S)(f: (S, A) => (S, A1))(implicit trace: Trace): ZStream[R, E, A1] =
ZStream.succeed(s).flatMap { s =>
def accumulator(currS: S): ZChannel[Any, E, Chunk[A], Any, E, Chunk[A1], Unit] =
ZChannel.readWithCause(
(in: Chunk[A]) => {
val (nextS, a1s) = in.mapAccum(currS)(f)
ZChannel.write(a1s) *> accumulator(nextS)
},
(err: Cause[E]) => ZChannel.refailCause(err),
(_: Any) => ZChannel.unit
)
new ZStream(self.channel >>> accumulator(s))
}
/**
* Statefully and effectfully maps over the elements of this stream to produce
* new elements.
*/
def mapAccumZIO[R1 <: R, E1 >: E, S, A1](
s: => S
)(f: (S, A) => ZIO[R1, E1, (S, A1)])(implicit trace: Trace): ZStream[R1, E1, A1] =
self >>> ZPipeline.mapAccumZIO(s)(f)
/**
* Returns a stream whose failure and success channels have been mapped by the
* specified pair of functions, `f` and `g`.
*/
def mapBoth[E1, A1](f: E => E1, g: A => A1)(implicit ev: CanFail[E], trace: Trace): ZStream[R, E1, A1] =
mapError(f).map(g)
/**
* Transforms the chunks emitted by this stream.
*/
def mapChunks[A2](f: Chunk[A] => Chunk[A2])(implicit trace: Trace): ZStream[R, E, A2] =
new ZStream(channel.mapOut(f))
/**
* Effectfully transforms the chunks emitted by this stream.
*/
def mapChunksZIO[R1 <: R, E1 >: E, A2](f: Chunk[A] => ZIO[R1, E1, Chunk[A2]])(implicit
trace: Trace
): ZStream[R1, E1, A2] =
new ZStream(channel.mapOutZIO(f))
/**
* Maps each element to an iterable, and flattens the iterables into the
* output of this stream.
*/
def mapConcat[A2](f: A => Iterable[A2])(implicit trace: Trace): ZStream[R, E, A2] =
mapConcatChunk(a => Chunk.fromIterable(f(a)))
/**
* Maps each element to a chunk, and flattens the chunks into the output of
* this stream.
*/
def mapConcatChunk[A2](f: A => Chunk[A2])(implicit trace: Trace): ZStream[R, E, A2] =
mapChunks(_.flatMap(f))
/**
* Effectfully maps each element to a chunk, and flattens the chunks into the
* output of this stream.
*/
def mapConcatChunkZIO[R1 <: R, E1 >: E, A2](f: A => ZIO[R1, E1, Chunk[A2]])(implicit
trace: Trace
): ZStream[R1, E1, A2] =
mapZIO(f).mapConcatChunk(identity)
/**
* Effectfully maps each element to an iterable, and flattens the iterables
* into the output of this stream.
*/
def mapConcatZIO[R1 <: R, E1 >: E, A2](f: A => ZIO[R1, E1, Iterable[A2]])(implicit
trace: Trace
): ZStream[R1, E1, A2] =
mapZIO(a => f(a).map(Chunk.fromIterable(_))).mapConcatChunk(identity)
/**
* Transforms the errors emitted by this stream using `f`.
*/
def mapError[E2](f: E => E2)(implicit trace: Trace): ZStream[R, E2, A] =
new ZStream(self.channel.mapError(f))
/**
* Transforms the full causes of failures emitted by this stream.
*/
def mapErrorCause[E2](f: Cause[E] => Cause[E2])(implicit trace: Trace): ZStream[R, E2, A] =
new ZStream(self.channel.mapErrorCause(f))
/**
* Maps over elements of the stream with the specified effectful function.
*/
def mapZIO[R1 <: R, E1 >: E, A1](f: A => ZIO[R1, E1, A1])(implicit trace: Trace): ZStream[R1, E1, A1] = {
def loop(chunkIterator: Chunk.ChunkIterator[A], index: Int): ZChannel[R1, E, Chunk[A], Any, E1, Chunk[A1], Any] =
if (chunkIterator.hasNextAt(index))
ZChannel.unwrap {
val a = chunkIterator.nextAt(index)
f(a).map { a1 =>
ZChannel.write(Chunk.single(a1)) *> loop(chunkIterator, index + 1)
}
}
else
ZChannel.readWithCause(
elem => loop(elem.chunkIterator, 0),
err => ZChannel.refailCause(err),
done => ZChannel.succeed(done)
)
new ZStream(self.channel >>> loop(Chunk.ChunkIterator.empty, 0))
}
/**
* Maps over elements of the stream with the specified effectful function,
* executing up to `n` invocations of `f` concurrently. Transformed elements
* will be emitted in the original order.
*
* @note
* This combinator destroys the chunking structure. It's recommended to use
* rechunk afterwards.
*/
def mapZIOPar[R1 <: R, E1 >: E, A2](n: => Int)(f: A => ZIO[R1, E1, A2])(implicit
trace: Trace
): ZStream[R1, E1, A2] =
mapZIOPar[R1, E1, A2](n, 16)(f)
/**
* Maps over elements of the stream with the specified effectful function,
* executing up to `n` invocations of `f` concurrently. Transformed elements
* will be emitted in the original order.
*
* @note
* This combinator destroys the chunking structure. It's recommended to use
* rechunk afterwards.
*/
def mapZIOPar[R1 <: R, E1 >: E, A2](n: => Int, bufferSize: Int = 16)(f: A => ZIO[R1, E1, A2])(implicit
trace: Trace
): ZStream[R1, E1, A2] =
self >>> ZPipeline.mapZIOPar(n, bufferSize)(f)
/**
* Maps over elements of the stream with the specified effectful function,
* partitioned by `p` executing invocations of `f` concurrently. The number of
* concurrent invocations of `f` is determined by the number of different
* outputs of type `K`. Up to `buffer` elements may be buffered per partition.
* Transformed elements may be reordered but the order within a partition is
* maintained.
*/
def mapZIOParByKey[R1 <: R, E1 >: E, A2, K](
keyBy: A => K,
buffer: => Int = 16
)(f: A => ZIO[R1, E1, A2])(implicit trace: Trace): ZStream[R1, E1, A2] =
groupByKey(keyBy, buffer).apply { case (_, s) => s.mapZIO(f) }
/**
* Maps over elements of the stream with the specified effectful function,
* executing up to `n` invocations of `f` concurrently. The element order is
* not enforced by this combinator, and elements may be reordered.
*/
def mapZIOParUnordered[R1 <: R, E1 >: E, A2](n: => Int)(f: A => ZIO[R1, E1, A2])(implicit
trace: Trace
): ZStream[R1, E1, A2] =
mapZIOParUnordered[R1, E1, A2](n, 16)(f)
/**
* Maps over elements of the stream with the specified effectful function,
* executing up to `n` invocations of `f` concurrently. The element order is
* not enforced by this combinator, and elements may be reordered.
*/
def mapZIOParUnordered[R1 <: R, E1 >: E, A2](n: => Int, bufferSize: => Int = 16)(f: A => ZIO[R1, E1, A2])(implicit
trace: Trace
): ZStream[R1, E1, A2] =
self >>> ZPipeline.mapZIOParUnordered(n, bufferSize)(f)
/**
* Merges this stream and the specified stream together.
*
* New produced stream will terminate when both specified stream terminate if
* no termination strategy is specified.
*/
def merge[R1 <: R, E1 >: E, A1 >: A](
that: => ZStream[R1, E1, A1],
strategy: => HaltStrategy = HaltStrategy.Both
)(implicit trace: Trace): ZStream[R1, E1, A1] = {
import HaltStrategy.{Either, Left, Right}
def handler(terminate: Boolean)(exit: Exit[E1, Any]): ZChannel.MergeDecision[R1, E1, Any, E1, Any] =
if (terminate || !exit.isSuccess) ZChannel.MergeDecision.done(ZIO.done(exit))
else ZChannel.MergeDecision.await(ZIO.done(_))
new ZStream(
ZChannel.succeed(strategy).flatMap { strategy =>
self.channel
.mergeWith(that.channel)(
handler(strategy == Either || strategy == Left),
handler(strategy == Either || strategy == Right)
)
}
)
}
/**
* Merges this stream and the specified stream together. New produced stream
* will terminate when either stream terminates.
*/
def mergeHaltEither[R1 <: R, E1 >: E, A1 >: A](that: => ZStream[R1, E1, A1])(implicit
trace: Trace
): ZStream[R1, E1, A1] =
self.merge[R1, E1, A1](that, HaltStrategy.Either)
/**
* Merges this stream and the specified stream together. New produced stream
* will terminate when this stream terminates.
*/
def mergeHaltLeft[R1 <: R, E1 >: E, A1 >: A](that: => ZStream[R1, E1, A1])(implicit
trace: Trace
): ZStream[R1, E1, A1] =
self.merge[R1, E1, A1](that, HaltStrategy.Left)
/**
* Merges this stream and the specified stream together. New produced stream
* will terminate when the specified stream terminates.
*/
def mergeHaltRight[R1 <: R, E1 >: E, A1 >: A](that: => ZStream[R1, E1, A1])(implicit
trace: Trace
): ZStream[R1, E1, A1] =
self.merge[R1, E1, A1](that, HaltStrategy.Right)
/**
* Merges this stream and the specified stream together to produce a stream of
* eithers.
*/
def mergeEither[R1 <: R, E1 >: E, A2](that: => ZStream[R1, E1, A2])(implicit
trace: Trace
): ZStream[R1, E1, Either[A, A2]] =
self.mergeWith(that)(Left(_), Right(_))
/**
* Merges this stream and the specified stream together, discarding the values
* from the right stream.
*/
def mergeLeft[R1 <: R, E1 >: E, A2](
that: => ZStream[R1, E1, A2],
strategy: HaltStrategy = HaltStrategy.Both
)(implicit
trace: Trace
): ZStream[R1, E1, A] =
self.merge(that.drain, strategy)
/**
* Merges this stream and the specified stream together, discarding the values
* from the left stream.
*/
def mergeRight[R1 <: R, E1 >: E, A2](
that: => ZStream[R1, E1, A2],
strategy: HaltStrategy = HaltStrategy.Both
)(implicit
trace: Trace
): ZStream[R1, E1, A2] =
self.drain.merge(that, strategy)
/**
* Merges this stream that is sorted and the specified stream that is sorted
* to produce a new stream that is sorted.
*/
def mergeSorted[R1 <: R, E1 >: E, A1 >: A](
that: => ZStream[R1, E1, A1]
)(implicit ord: Ordering[A1], trace: Trace): ZStream[R1, E1, A1] = {
sealed trait State
case object DrainLeft extends State
case object DrainRight extends State
case object PullBoth extends State
final case class PullLeft(rightChunk: Chunk[A1]) extends State
final case class PullRight(leftChunk: Chunk[A1]) extends State
def pull(
state: State,
pullLeft: ZIO[R, Option[E], Chunk[A1]],
pullRight: ZIO[R1, Option[E1], Chunk[A1]]
): ZIO[R1, Nothing, Exit[Option[E1], (Chunk[A1], State)]] =
state match {
case DrainLeft =>
pullLeft.fold(
e => Exit.fail(e),
leftChunk => Exit.succeed(leftChunk -> DrainLeft)
)
case DrainRight =>
pullRight.fold(
e => Exit.fail(e),
rightChunk => Exit.succeed(rightChunk -> DrainRight)
)
case PullBoth =>
pullLeft.unsome
.zipPar(pullRight.unsome)
.foldZIO(
e => ZIO.succeed(Exit.fail(Some(e))),
{
case (Some(leftChunk), Some(rightChunk)) =>
if (leftChunk.isEmpty && rightChunk.isEmpty) pull(PullBoth, pullLeft, pullRight)
else if (leftChunk.isEmpty) pull(PullLeft(rightChunk), pullLeft, pullRight)
else if (rightChunk.isEmpty) pull(PullRight(leftChunk), pullLeft, pullRight)
else ZIO.succeed(Exit.succeed(mergeSortedChunk(leftChunk, rightChunk)))
case (Some(leftChunk), None) =>
if (leftChunk.isEmpty) pull(DrainLeft, pullLeft, pullRight)
else ZIO.succeed(Exit.succeed(leftChunk -> DrainLeft))
case (None, Some(rightChunk)) =>
if (rightChunk.isEmpty) pull(DrainRight, pullLeft, pullRight)
else
ZIO.succeed(Exit.succeed(rightChunk -> DrainRight))
case (None, None) => ZIO.succeed(Exit.fail(None))
}
)
case PullLeft(rightChunk) =>
pullLeft.foldZIO(
{
case Some(e) => ZIO.succeed(Exit.fail(Some(e)))
case None =>
ZIO.succeed(Exit.succeed(rightChunk -> DrainRight))
},
leftChunk =>
if (leftChunk.isEmpty) pull(PullLeft(rightChunk), pullLeft, pullRight)
else ZIO.succeed(Exit.succeed(mergeSortedChunk(leftChunk, rightChunk)))
)
case PullRight(leftChunk) =>
pullRight.foldZIO(
{
case Some(e) => ZIO.succeed(Exit.fail(Some(e)))
case None => ZIO.succeed(Exit.succeed(leftChunk -> DrainLeft))
},
rightChunk =>
if (rightChunk.isEmpty) pull(PullRight(leftChunk), pullLeft, pullRight)
else ZIO.succeed(Exit.succeed(mergeSortedChunk(leftChunk, rightChunk)))
)
}
def mergeSortedChunk(
leftChunk: Chunk[A1],
rightChunk: Chunk[A1]
): (Chunk[A1], State) = {
val builder = ChunkBuilder.make[A1]()
var state = null.asInstanceOf[State]
val leftIterator = leftChunk.iterator
val rightIterator = rightChunk.iterator
var left = leftIterator.next()
var right = rightIterator.next()
var loop = true
while (loop) {
val compare = ord.compare(left, right)
if (compare == 0) {
builder += left
builder += right
if (leftIterator.hasNext && rightIterator.hasNext) {
left = leftIterator.next()
right = rightIterator.next()
} else if (leftIterator.hasNext) {
state = PullRight(Chunk.fromIterator(leftIterator))
loop = false
} else if (rightIterator.hasNext) {
state = PullLeft(Chunk.fromIterator(rightIterator))
loop = false
} else {
state = PullBoth
loop = false
}
} else if (compare < 0) {
builder += left
if (leftIterator.hasNext) {
left = leftIterator.next()
} else {
val rightBuilder = ChunkBuilder.make[A1]()
rightBuilder += right
rightBuilder ++= rightIterator
state = PullLeft(rightBuilder.result())
loop = false
}
} else {
builder += right
if (rightIterator.hasNext) {
right = rightIterator.next()
} else {
val leftBuilder = ChunkBuilder.make[A1]()
leftBuilder += left
leftBuilder ++= leftIterator
state = PullRight(leftBuilder.result())
loop = false
}
}
}
(builder.result(), state)
}
self.combineChunks[R1, E1, State, A1, A1](that)(PullBoth)(pull)
}
/**
* Merges this stream and the specified stream together to a common element
* type with the specified mapping functions.
*
* New produced stream will terminate when both specified stream terminate if
* no termination strategy is specified.
*/
def mergeWith[R1 <: R, E1 >: E, A2, A3](
that: => ZStream[R1, E1, A2],
strategy: => HaltStrategy = HaltStrategy.Both
)(l: A => A3, r: A2 => A3)(implicit trace: Trace): ZStream[R1, E1, A3] =
self
.map(l)
.merge(that.map(r), strategy)
/**
* Runs the specified effect if this stream fails, providing the error to the
* effect if it exists.
*
* Note: Unlike [[ZIO.onError]], there is no guarantee that the provided
* effect will not be interrupted.
*/
def onError[R1 <: R](cleanup: Cause[E] => URIO[R1, Any])(implicit trace: Trace): ZStream[R1, E, A] =
catchAllCause(cause => ZStream.fromZIO(cleanup(cause) *> Exit.failCause(cause)))
/**
* Locks the execution of this stream to the specified executor. Any streams
* that are composed after this one will automatically be shifted back to the
* previous executor.
*/
def onExecutor(executor: => Executor)(implicit trace: Trace): ZStream[R, E, A] =
ZStream.scoped(ZIO.onExecutorScoped(executor)) *> self
/**
* Translates any failure into a stream termination, making the stream
* infallible and all failures unchecked.
*/
def orDie(implicit ev1: E IsSubtypeOfError Throwable, ev2: CanFail[E], trace: Trace): ZStream[R, Nothing, A] =
self.orDieWith(ev1)
/**
* Keeps none of the errors, and terminates the stream with them, using the
* specified function to convert the `E` into a `Throwable`.
*/
def orDieWith(f: E => Throwable)(implicit ev: CanFail[E], trace: Trace): ZStream[R, Nothing, A] =
new ZStream(self.channel.orDieWith(f))
/**
* Switches to the provided stream in case this one fails with a typed error.
*
* See also [[ZStream#catchAll]].
*/
def orElse[R1 <: R, E1, A1 >: A](
that: => ZStream[R1, E1, A1]
)(implicit ev: CanFail[E], trace: Trace): ZStream[R1, E1, A1] =
new ZStream(self.channel.orElse(that.channel))
/**
* Switches to the provided stream in case this one fails with a typed error.
*
* See also [[ZStream#catchAll]].
*/
def orElseEither[R1 <: R, E2, A2](
that: => ZStream[R1, E2, A2]
)(implicit ev: CanFail[E], trace: Trace): ZStream[R1, E2, Either[A, A2]] =
self.map(Left(_)) orElse that.map(Right(_))
/**
* Fails with given error in case this one fails with a typed error.
*
* See also [[ZStream#catchAll]].
*/
def orElseFail[E1](e1: => E1)(implicit ev: CanFail[E], trace: Trace): ZStream[R, E1, A] =
orElse(ZStream.fail(e1))
/**
* Produces the specified element if this stream is empty.
*/
def orElseIfEmpty[A1 >: A](a: A1)(implicit trace: Trace): ZStream[R, E, A1] =
orElseIfEmpty(Chunk.single(a))
/**
* Produces the specified chunk if this stream is empty.
*/
def orElseIfEmpty[A1 >: A](chunk: Chunk[A1])(implicit trace: Trace): ZStream[R, E, A1] =
orElseIfEmpty(new ZStream(ZChannel.write(chunk)))
/**
* Switches to the provided stream in case this one is empty.
*/
def orElseIfEmpty[R1 <: R, E1 >: E, A1 >: A](
stream: ZStream[R1, E1, A1]
)(implicit trace: Trace): ZStream[R1, E1, A1] = {
lazy val writer: ZChannel[R1, E, Chunk[A], Any, E1, Chunk[A1], Any] =
ZChannel.readWithCause(
(in: Chunk[A]) => if (in.isEmpty) writer else ZChannel.write(in) *> ZChannel.identity[E, Chunk[A], Any],
(e: Cause[E]) => ZChannel.refailCause(e),
(_: Any) => stream.channel
)
new ZStream(self.channel >>> writer)
}
/**
* Switches to the provided stream in case this one fails with the `None`
* value.
*
* See also [[ZStream#catchAll]].
*/
def orElseOptional[R1 <: R, E1, A1 >: A](
that: => ZStream[R1, Option[E1], A1]
)(implicit ev: E <:< Option[E1], trace: Trace): ZStream[R1, Option[E1], A1] =
catchAll(ev(_).fold(that)(e => ZStream.fail(Some(e))))
/**
* Succeeds with the specified value if this one fails with a typed error.
*/
def orElseSucceed[A1 >: A](A1: => A1)(implicit ev: CanFail[E], trace: Trace): ZStream[R, Nothing, A1] =
orElse(ZStream.succeed(A1))
/**
* Partition a stream using a predicate. The first stream will contain all
* element evaluated to true and the second one will contain all element
* evaluated to false. The faster stream may advance by up to buffer elements
* further than the slower one.
*/
def partition(p: A => Boolean, buffer: => Int = 16)(implicit
trace: Trace
): ZIO[R with Scope, Nothing, (ZStream[Any, E, A], ZStream[Any, E, A])] =
self.partitionEither(a => if (p(a)) ZIO.succeed(Left(a)) else ZIO.succeed(Right(a)), buffer)
/**
* Split a stream by a predicate. The faster stream may advance by up to
* buffer elements further than the slower one.
*/
def partitionEither[R1 <: R, E1 >: E, A2, A3](
p: A => ZIO[R1, E1, Either[A2, A3]],
buffer: => Int = 16
)(implicit trace: Trace): ZIO[R1 with Scope, Nothing, (ZStream[Any, E1, A2], ZStream[Any, E1, A3])] =
self
.mapZIO(p)
.distributedWith(
2,
buffer,
{
case Left(_) => ZIO.succeed(_ == 0)
case Right(_) => ZIO.succeed(_ == 1)
}
)
.flatMap {
case q1 :: q2 :: Nil =>
ZIO.succeed {
(
ZStream.fromQueueWithShutdown(q1).flattenExitOption.collectLeft,
ZStream.fromQueueWithShutdown(q2).flattenExitOption.collectRight
)
}
case otherwise => ZIO.dieMessage(s"partitionEither: expected two streams but got $otherwise")
}
/**
* Peels off enough material from the stream to construct a `Z` using the
* provided [[ZSink]] and then returns both the `Z` and the rest of the
* [[ZStream]] in a scope. Like all scoped values, the provided stream is
* valid only within the scope.
*/
def peel[R1 <: R, E1 >: E, A1 >: A, Z](
sink: => ZSink[R1, E1, A1, A1, Z]
)(implicit trace: Trace): ZIO[R1 with Scope, E1, (Z, ZStream[Any, E, A1])] = {
sealed trait Signal
object Signal {
case class Emit(els: Chunk[A1]) extends Signal
case class Halt(cause: Cause[E]) extends Signal
case object End extends Signal
}
(for {
p <- Promise.make[E1, Z]
handoff <- ZStream.Handoff.make[Signal]
} yield {
val consumer: ZSink[R1, E1, A1, A1, Unit] = sink.collectLeftover
.foldCauseSink(
c => ZSink.fromZIO(p.failCause(c)) *> ZSink.failCause(c),
{ case (z1, leftovers) =>
lazy val loop: ZChannel[Any, E, Chunk[A1], Any, E1, Chunk[A1], Unit] = ZChannel.readWithCause(
(in: Chunk[A1]) => ZChannel.fromZIO(handoff.offer(Signal.Emit(in))) *> loop,
(e: Cause[E]) => ZChannel.fromZIO(handoff.offer(Signal.Halt(e))) *> ZChannel.refailCause(e),
(_: Any) => ZChannel.fromZIO(handoff.offer(Signal.End)) *> ZChannel.unit
)
ZSink.fromChannel(
ZChannel.fromZIO(p.succeed(z1)) *>
ZChannel.fromZIO(handoff.offer(Signal.Emit(leftovers))) *>
loop
)
}
)
lazy val producer: ZChannel[Any, Any, Any, Any, E, Chunk[A1], Unit] = ZChannel.unwrap(
handoff.take.map {
case Signal.Emit(els) => ZChannel.write(els) *> producer
case Signal.Halt(cause) => ZChannel.refailCause(cause)
case Signal.End => ZChannel.unit
}
)
for {
_ <- self.tapErrorCause(cause => p.failCause(cause)).run(consumer).forkScoped
z <- p.await
} yield (z, new ZStream(producer))
}).flatten
}
/**
* Pipes all of the values from this stream through the provided sink.
*
* @see
* [[transduce]]
*/
def pipeThrough[R1 <: R, E1 >: E, L, Z](sink: => ZSink[R1, E1, A, L, Z])(implicit
trace: Trace
): ZStream[R1, E1, L] =
new ZStream(self.channel pipeToOrFail sink.channel)
/**
* Pipes all the values from this stream through the provided channel
*/
def pipeThroughChannel[R1 <: R, E2, A2](channel: => ZChannel[R1, E, Chunk[A], Any, E2, Chunk[A2], Any])(implicit
trace: Trace
): ZStream[R1, E2, A2] =
new ZStream(self.channel >>> channel)
/**
* Pipes all values from this stream through the provided channel, passing
* through any error emitted by this stream unchanged.
*/
def pipeThroughChannelOrFail[R1 <: R, E1 >: E, A2](channel: ZChannel[R1, Nothing, Chunk[A], Any, E1, Chunk[A2], Any])(
implicit trace: Trace
): ZStream[R1, E1, A2] =
new ZStream(self.channel pipeToOrFail channel)
/**
* Provides the stream with its required environment, which eliminates its
* dependency on `R`.
*/
def provideEnvironment(
r: => ZEnvironment[R]
)(implicit trace: Trace): ZStream[Any, E, A] =
new ZStream(channel.provideEnvironment(r))
/**
* Provides a layer to the stream, which translates it to another level.
*/
def provideLayer[E1 >: E, R0](
layer: => ZLayer[R0, E1, R]
)(implicit trace: Trace): ZStream[R0, E1, A] =
new ZStream(
ZChannel.unwrapScopedWith { scope =>
layer.build(scope).map(r => self.channel.provideEnvironment(r))
}
)
/**
* Transforms the environment being provided to the stream with the specified
* function.
*/
def provideSomeEnvironment[R0](
env: ZEnvironment[R0] => ZEnvironment[R]
)(implicit trace: Trace): ZStream[R0, E, A] =
ZStream.environmentWithStream[R0] { r0 =>
self.provideEnvironment(env(r0))
}
/**
* Splits the environment into two parts, providing one part using the
* specified layer and leaving the remainder `R0`.
*
* {{{
* val loggingLayer: ZLayer[Any, Nothing, Logging] = ???
*
* val stream: ZStream[Logging with Database, Nothing, Unit] = ???
*
* val stream2 = stream.provideSomeLayer[Database](loggingLayer)
* }}}
*/
def provideSomeLayer[R0]: ZStream.ProvideSomeLayer[R0, R, E, A] =
new ZStream.ProvideSomeLayer[R0, R, E, A](self)
/**
* Re-chunks the elements of the stream into chunks of `n` elements each. The
* last chunk might contain less than `n` elements
*/
def rechunk(n: => Int)(implicit trace: Trace): ZStream[R, E, A] =
self >>> ZPipeline.rechunk(n)
/**
* Keeps some of the errors, and terminates the fiber with the rest
*/
def refineOrDie[E1](
pf: PartialFunction[E, E1]
)(implicit ev1: E <:< Throwable, ev2: CanFail[E], trace: Trace): ZStream[R, E1, A] =
refineOrDieWith(pf)(identity(_))
/**
* Keeps some of the errors, and terminates the fiber with the rest, using the
* specified function to convert the `E` into a `Throwable`.
*/
def refineOrDieWith[E1](
pf: PartialFunction[E, E1]
)(f: E => Throwable)(implicit ev: CanFail[E], trace: Trace): ZStream[R, E1, A] =
mapErrorCause(_.flatMap(pf.andThen(Cause.fail(_)).applyOrElse(_, (e: E) => Cause.die(f(e)))))
/**
* Repeats the entire stream using the specified schedule. The stream will
* execute normally, and then repeat again according to the provided schedule.
*/
def repeat[R1 <: R, B](schedule: => Schedule[R1, Any, B])(implicit
trace: Trace
): ZStream[R1, E, A] =
repeatEither(schedule) collect { case Right(a) => a }
/**
* Repeats the entire stream using the specified schedule. The stream will
* execute normally, and then repeat again according to the provided schedule.
* The schedule output will be emitted at the end of each repetition.
*/
def repeatEither[R1 <: R, B](schedule: => Schedule[R1, Any, B])(implicit
trace: Trace
): ZStream[R1, E, Either[B, A]] =
repeatWith(schedule)(Right(_), Left(_))
/**
* Repeats each element of the stream using the provided schedule. Repetitions
* are done in addition to the first execution, which means using
* `Schedule.recurs(1)` actually results in the original effect, plus an
* additional recurrence, for a total of two repetitions of each value in the
* stream.
*/
def repeatElements[R1 <: R](schedule: => Schedule[R1, A, Any])(implicit
trace: Trace
): ZStream[R1, E, A] =
repeatElementsEither(schedule).collect { case Right(a) => a }
/**
* Repeats each element of the stream using the provided schedule. When the
* schedule is finished, then the output of the schedule will be emitted into
* the stream. Repetitions are done in addition to the first execution, which
* means using `Schedule.recurs(1)` actually results in the original effect,
* plus an additional recurrence, for a total of two repetitions of each value
* in the stream.
*/
def repeatElementsEither[R1 <: R, E1 >: E, B](
schedule: => Schedule[R1, A, B]
)(implicit trace: Trace): ZStream[R1, E1, Either[B, A]] =
repeatElementsWith(schedule)(Right.apply, Left.apply)
/**
* Repeats each element of the stream using the provided schedule. When the
* schedule is finished, then the output of the schedule will be emitted into
* the stream. Repetitions are done in addition to the first execution, which
* means using `Schedule.recurs(1)` actually results in the original effect,
* plus an additional recurrence, for a total of two repetitions of each value
* in the stream.
*
* This function accepts two conversion functions, which allow the output of
* this stream and the output of the provided schedule to be unified into a
* single type. For example, `Either` or similar data type.
*/
def repeatElementsWith[R1 <: R, E1 >: E, B, C](
schedule: => Schedule[R1, A, B]
)(f: A => C, g: B => C)(implicit trace: Trace): ZStream[R1, E1, C] = new ZStream(
self.channel >>> ZChannel.unwrap {
for {
driver <- schedule.driver
} yield {
def feed(in: Chunk[A]): ZChannel[R1, E1, Chunk[A], Any, E1, Chunk[C], Unit] =
in.headOption.fold(loop)(a => ZChannel.write(Chunk.single(f(a))) *> step(in.drop(1), a))
def step(in: Chunk[A], a: A): ZChannel[R1, E1, Chunk[A], Any, E1, Chunk[C], Unit] = {
val advance = driver.next(a).as(ZChannel.write(Chunk.single(f(a))) *> step(in, a))
val reset: ZIO[R1, Nothing, ZChannel[R1, E1, Chunk[A], Any, E1, Chunk[C], Unit]] =
for {
b <- driver.last.orDie
_ <- driver.reset
} yield ZChannel.write(Chunk.single(g(b))) *> feed(in)
ZChannel.unwrap(advance orElse reset)
}
lazy val loop: ZChannel[R1, E1, Chunk[A], Any, E1, Chunk[C], Unit] =
ZChannel.readWithCause(
feed,
ZChannel.refailCause,
(_: Any) => ZChannel.unit
)
loop
}
}
)
/**
* Repeats the entire stream using the specified schedule. The stream will
* execute normally, and then repeat again according to the provided schedule.
* The schedule output will be emitted at the end of each repetition and can
* be unified with the stream elements using the provided functions.
*/
def repeatWith[R1 <: R, B, C](
schedule: => Schedule[R1, Any, B]
)(f: A => C, g: B => C)(implicit trace: Trace): ZStream[R1, E, C] =
ZStream.unwrap(
for {
driver <- schedule.driver
} yield {
val scheduleOutput = driver.last.orDie.map(g)
val process = self.map(f).channel
lazy val loop: ZChannel[R1, Any, Any, Any, E, Chunk[C], Unit] =
ZChannel.unwrap(
driver
.next(())
.fold(
_ => ZChannel.unit,
_ => process *> ZChannel.unwrap(scheduleOutput.map(o => ZChannel.write(Chunk.single(o)))) *> loop
)
)
new ZStream(process *> loop)
}
)
/**
* When the stream fails, retry it according to the given schedule
*
* This retries the entire stream, so will re-execute all of the stream's
* acquire operations.
*
* The schedule is reset as soon as the first element passes through the
* stream again.
*
* @param schedule
* Schedule receiving as input the errors of the stream
* @return
* Stream outputting elements of all attempts of the stream
*/
def retry[R1 <: R](
schedule: => Schedule[R1, E, _]
)(implicit trace: Trace): ZStream[R1, E, A] =
ZStream.unwrap {
for {
driver <- schedule.driver
} yield {
def loop: ZStream[R1, E, A] = self.catchAll { e =>
ZStream.unwrap(
driver
.next(e)
.foldZIO(
_ => Exit.failCause(Cause.fail(e)),
_ => ZIO.succeed(loop.tap(_ => driver.reset))
)
)
}
loop
}
}
/**
* Fails with the error `None` if value is `Left`.
*/
def right[A1, A2](implicit ev: A <:< Either[A1, A2], trace: Trace): ZStream[R, Option[E], A2] =
self.mapError(Some(_)).rightOrFail(None)
/**
* Fails with given error 'e' if value is `Left`.
*/
def rightOrFail[A1, A2, E1 >: E](
e: => E1
)(implicit ev: A <:< Either[A1, A2], trace: Trace): ZStream[R, E1, A2] =
self.mapZIO(ev(_).fold(_ => ZIO.fail(e), ZIO.succeed(_)))
/**
* Runs the sink on the stream to produce either the sink's result or an
* error.
*/
def run[R1 <: R, E1 >: E, Z](sink: => ZSink[R1, E1, A, Any, Z])(implicit trace: Trace): ZIO[R1, E1, Z] =
(channel pipeToOrFail sink.channel).runDrain
def runScoped[R1 <: R, E1 >: E, B](sink: => ZSink[R1, E1, A, Any, B])(implicit
trace: Trace
): ZIO[R1 with Scope, E1, B] =
(channel pipeToOrFail sink.channel).drain.runScoped
/**
* Runs the stream and collects all of its elements to a chunk.
*/
def runCollect(implicit trace: Trace): ZIO[R, E, Chunk[A]] =
run(ZSink.collectAll)
/**
* Runs the stream and emits the number of elements processed
*
* Equivalent to `run(ZSink.count)`
*/
def runCount(implicit trace: Trace): ZIO[R, E, Long] =
run(ZSink.count)
/**
* Runs the stream only for its effects. The emitted elements are discarded.
*/
def runDrain(implicit trace: Trace): ZIO[R, E, Unit] =
run(ZSink.drain)
/**
* Executes a pure fold over the stream of values - reduces all elements in
* the stream to a value of type `S`.
*/
def runFold[S](s: => S)(f: (S, A) => S)(implicit trace: Trace): ZIO[R, E, S] =
runFoldWhile(s)(_ => true)((s, a) => f(s, a))
/**
* Executes a pure fold over the stream of values. Returns a scoped value that
* represents the scope of the stream.
*/
def runFoldScoped[S](s: => S)(f: (S, A) => S)(implicit trace: Trace): ZIO[R with Scope, E, S] =
runFoldWhileScoped(s)(_ => true)((s, a) => f(s, a))
/**
* Executes an effectful fold over the stream of values. Returns a scoped
* value that represents the scope of the stream.
*/
def runFoldScopedZIO[R1 <: R, E1 >: E, S](s: => S)(f: (S, A) => ZIO[R1, E1, S])(implicit
trace: Trace
): ZIO[R1 with Scope, E1, S] =
runFoldWhileScopedZIO[R1, E1, S](s)(_ => true)(f)
/**
* Reduces the elements in the stream to a value of type `S`. Stops the fold
* early when the condition is not fulfilled. Example:
* {{{
* Stream(1).forever.foldWhile(0)(_ <= 4)(_ + _) // UIO[Int] == 5
* }}}
*/
def runFoldWhile[S](s: => S)(cont: S => Boolean)(f: (S, A) => S)(implicit trace: Trace): ZIO[R, E, S] =
run(ZSink.fold(s)(cont)(f))
/**
* Executes an effectful fold over the stream of values. Returns a scoped
* value that represents the scope of the stream. Stops the fold early when
* the condition is not fulfilled. Example:
* {{{
* Stream(1)
* .forever // an infinite Stream of 1's
* .fold(0)(_ <= 4)((s, a) => ZIO.succeed(s + a)) // URIO[Scope, Int] == 5
* }}}
*
* @param cont
* function which defines the early termination condition
*/
def runFoldWhileScopedZIO[R1 <: R, E1 >: E, S](
s: => S
)(cont: S => Boolean)(f: (S, A) => ZIO[R1, E1, S])(implicit trace: Trace): ZIO[R1 with Scope, E1, S] =
runScoped(ZSink.foldZIO(s)(cont)(f))
/**
* Executes an effectful fold over the stream of values. Stops the fold early
* when the condition is not fulfilled. Example:
* {{{
* Stream(1)
* .forever // an infinite Stream of 1's
* .fold(0)(_ <= 4)((s, a) => ZIO.succeed(s + a)) // UIO[Int] == 5
* }}}
*
* @param cont
* function which defines the early termination condition
*/
def runFoldWhileZIO[R1 <: R, E1 >: E, S](s: => S)(cont: S => Boolean)(
f: (S, A) => ZIO[R1, E1, S]
)(implicit trace: Trace): ZIO[R1, E1, S] =
run(ZSink.foldZIO(s)(cont)(f))
/**
* Executes a pure fold over the stream of values. Returns a scoped value that
* represents the scope of the stream. Stops the fold early when the condition
* is not fulfilled.
*/
def runFoldWhileScoped[S](s: => S)(cont: S => Boolean)(f: (S, A) => S)(implicit
trace: Trace
): ZIO[R with Scope, E, S] =
runScoped(ZSink.fold(s)(cont)(f))
/**
* Executes an effectful fold over the stream of values.
*/
def runFoldZIO[R1 <: R, E1 >: E, S](s: => S)(f: (S, A) => ZIO[R1, E1, S])(implicit
trace: Trace
): ZIO[R1, E1, S] =
runFoldWhileZIO[R1, E1, S](s)(_ => true)(f)
/**
* Consumes all elements of the stream, passing them to the specified
* callback.
*/
def runForeach[R1 <: R, E1 >: E](f: A => ZIO[R1, E1, Any])(implicit trace: Trace): ZIO[R1, E1, Unit] =
run(ZSink.foreach(f))
/**
* Consumes all elements of the stream, passing them to the specified
* callback.
*/
def runForeachChunk[R1 <: R, E1 >: E](f: Chunk[A] => ZIO[R1, E1, Any])(implicit
trace: Trace
): ZIO[R1, E1, Unit] =
run(ZSink.foreachChunk(f))
/**
* Like [[ZStream#runForeachChunk]], but returns a scoped `ZIO` so the
* finalization order can be controlled.
*/
def runForeachChunkScoped[R1 <: R, E1 >: E](f: Chunk[A] => ZIO[R1, E1, Any])(implicit
trace: Trace
): ZIO[R1 with Scope, E1, Unit] =
runScoped(ZSink.foreachChunk(f))
/**
* Like [[ZStream#foreach]], but returns a scoped `ZIO` so the finalization
* order can be controlled.
*/
def runForeachScoped[R1 <: R, E1 >: E](f: A => ZIO[R1, E1, Any])(implicit
trace: Trace
): ZIO[R1 with Scope, E1, Unit] =
runScoped(ZSink.foreach(f))
/**
* Consumes elements of the stream, passing them to the specified callback,
* and terminating consumption when the callback returns `false`.
*/
def runForeachWhile[R1 <: R, E1 >: E](f: A => ZIO[R1, E1, Boolean])(implicit
trace: Trace
): ZIO[R1, E1, Unit] =
run(ZSink.foreachWhile(f))
/**
* Like [[ZStream#runForeachWhile]], but returns a scoped `ZIO` so the
* finalization order can be controlled.
*/
def runForeachWhileScoped[R1 <: R, E1 >: E](f: A => ZIO[R1, E1, Boolean])(implicit
trace: Trace
): ZIO[R1 with Scope, E1, Unit] =
runScoped(ZSink.foreachWhile(f))
/**
* Runs the stream to completion and yields the first value emitted by it,
* discarding the rest of the elements.
*/
def runHead(implicit trace: Trace): ZIO[R, E, Option[A]] =
run(ZSink.head)
/**
* Publishes elements of this stream to a hub. Stream failure and ending will
* also be signalled.
*/
def runIntoHub[E1 >: E, A1 >: A](
hub: => Hub[Take[E1, A1]]
)(implicit trace: Trace): ZIO[R, Nothing, Unit] =
runIntoQueue(hub)
/**
* Like [[ZStream#runIntoHub]], but provides the result as a scoped [[ZIO]] to
* allow for scope composition.
*/
def runIntoHubScoped[E1 >: E, A1 >: A](
hub: => Hub[Take[E1, A1]]
)(implicit trace: Trace): ZIO[R with Scope, Nothing, Unit] =
runIntoQueueScoped(hub)
/**
* Enqueues elements of this stream into a queue. Stream failure and ending
* will also be signalled.
*/
def runIntoQueue(
queue: => Enqueue[Take[E, A]]
)(implicit trace: Trace): ZIO[R, Nothing, Unit] =
ZIO.scoped[R](runIntoQueueScoped(queue))
/**
* Like [[ZStream#runIntoQueue]], but provides the result as a scoped [[ZIO]
* to allow for scope composition.
*/
def runIntoQueueScoped(
queue: => Enqueue[Take[E, A]]
)(implicit trace: Trace): ZIO[R with Scope, Nothing, Unit] = {
lazy val writer: ZChannel[R, E, Chunk[A], Any, Nothing, Take[E, A], Any] = ZChannel
.readWithCause[R, E, Chunk[A], Any, Nothing, Take[E, A], Any](
in => ZChannel.write(Take.chunk(in)) *> writer,
cause => ZChannel.write(Take.failCause(cause)),
_ => ZChannel.write(Take.end)
)
(self.channel >>> writer)
.mapOutZIO(queue.offer)
.drain
.runScoped
.unit
}
/**
* Like [[ZStream#runIntoQueue]], but provides the result as a scoped [[ZIO]]
* to allow for scope composition.
*/
def runIntoQueueElementsScoped(
queue: => Enqueue[Exit[Option[E], A]]
)(implicit trace: Trace): ZIO[R with Scope, Nothing, Unit] = {
lazy val writer: ZChannel[R, E, Chunk[A], Any, Nothing, Exit[Option[E], A], Any] =
ZChannel.readWithCause[R, E, Chunk[A], Any, Nothing, Exit[Option[E], A], Any](
in => ZChannel.fromZIO(queue.offerAll(in.map(Exit.succeed(_)))) *> writer,
err => ZChannel.fromZIO(queue.offer(Exit.failCause(err.map(Some(_))))),
_ => ZChannel.fromZIO(queue.offer(Exit.fail(None)))
)
(self.channel >>> writer).drain.runScoped.unit
}
/**
* Runs the stream to completion and yields the last value emitted by it,
* discarding the rest of the elements.
*/
def runLast(implicit trace: Trace): ZIO[R, E, Option[A]] =
run(ZSink.last)
/**
* Runs the stream to a sink which sums elements, provided they are Numeric.
*
* Equivalent to `run(Sink.sum[A])`
*/
def runSum[A1 >: A](implicit ev: Numeric[A1], trace: Trace): ZIO[R, E, A1] =
run(ZSink.sum[A1])
/**
* Statefully maps over the elements of this stream to produce all
* intermediate results of type `S` given an initial S.
*/
def scan[S](s: => S)(f: (S, A) => S)(implicit trace: Trace): ZStream[R, E, S] =
scanZIO(s)((s, a) => ZIO.succeed(f(s, a)))
/**
* Statefully maps over the elements of this stream to produce all
* intermediate results.
*
* See also [[ZStream#scan]].
*/
def scanReduce[A1 >: A](f: (A1, A) => A1)(implicit trace: Trace): ZStream[R, E, A1] =
scanReduceZIO[R, E, A1]((curr, next) => ZIO.succeed(f(curr, next)))
/**
* Statefully and effectfully maps over the elements of this stream to produce
* all intermediate results.
*
* See also [[ZStream#scanZIO]].
*/
def scanReduceZIO[R1 <: R, E1 >: E, A1 >: A](
f: (A1, A) => ZIO[R1, E1, A1]
)(implicit trace: Trace): ZStream[R1, E1, A1] =
mapAccumZIO[R1, E1, Option[A1], A1](Option.empty[A1]) {
case (Some(a1), a) => f(a1, a).map(a2 => Some(a2) -> a2)
case (None, a) => ZIO.succeed(Some(a) -> a)
}
/**
* Statefully and effectfully maps over the elements of this stream to produce
* all intermediate results of type `S` given an initial S.
*/
def scanZIO[R1 <: R, E1 >: E, S](s: => S)(f: (S, A) => ZIO[R1, E1, S])(implicit
trace: Trace
): ZStream[R1, E1, S] =
self >>> ZPipeline.scanZIO(s)(f)
/**
* Schedules the output of the stream using the provided `schedule` and emits
* its output at the end (if `schedule` is finite).
*/
def scheduleEither[R1 <: R, E1 >: E, B](
schedule: => Schedule[R1, A, B]
)(implicit trace: Trace): ZStream[R1, E1, Either[B, A]] =
scheduleWith(schedule)(Right.apply, Left.apply)
/**
* Schedules the output of the stream using the provided `schedule`.
*/
def schedule[R1 <: R](schedule: => Schedule[R1, A, Any])(implicit
trace: Trace
): ZStream[R1, E, A] =
scheduleEither(schedule).collect { case Right(a) => a }
/**
* Schedules the output of the stream using the provided `schedule` and emits
* its output at the end (if `schedule` is finite). Uses the provided function
* to align the stream and schedule outputs on the same type.
*/
def scheduleWith[R1 <: R, E1 >: E, B, C](
schedule: => Schedule[R1, A, B]
)(f: A => C, g: B => C)(implicit trace: Trace): ZStream[R1, E1, C] = {
def loop(
driver: Schedule.Driver[Any, R1, A, B],
chunkIterator: Chunk.ChunkIterator[A],
index: Int
): ZChannel[R1, E1, Chunk[A], Any, E1, Chunk[C], Any] =
if (chunkIterator.hasNextAt(index))
ZChannel.unwrap {
val a = chunkIterator.nextAt(index)
driver
.next(a)
.foldZIO(
_ =>
driver.last.orDie.map { b =>
ZChannel.write(Chunk(f(a), g(b))) *> loop(driver, chunkIterator, index + 1)
} <* driver.reset,
_ => ZIO.succeed(ZChannel.write(Chunk.single(f(a))) *> loop(driver, chunkIterator, index + 1))
)
}
else
ZChannel.readWithCause(
chunk => loop(driver, chunk.chunkIterator, 0),
ZChannel.refailCause,
ZChannel.succeedNow(_)
)
new ZStream(ZChannel.fromZIO(schedule.driver).flatMap(self.channel >>> loop(_, Chunk.ChunkIterator.empty, 0)))
}
/**
* Converts an option on values into an option on errors.
*/
def some[A2](implicit ev: A <:< Option[A2], trace: Trace): ZStream[R, Option[E], A2] =
self.mapError(Some(_)).someOrFail(None)
/**
* Extracts the optional value, or returns the given 'default'. Superseded by
* `someOrElse` with better type inference. This method was left for binary
* compatibility.
*/
protected def someOrElse[A2](default: => A2)(implicit ev: A <:< Option[A2], trace: Trace): ZStream[R, E, A2] =
map(_.getOrElse(default))
/**
* Extracts the optional value, or returns the given 'default'.
*/
def someOrElse[A2, C](default: => C)(implicit ev0: A <:< Option[A2], ev1: C <:< A2, trace: Trace): ZStream[R, E, A2] =
map(_.getOrElse(default))
/**
* Extracts the optional value, or fails with the given error 'e'.
*/
def someOrFail[A2, E1 >: E](e: => E1)(implicit ev: A <:< Option[A2], trace: Trace): ZStream[R, E1, A2] =
self.mapZIO(ev(_).fold[IO[E1, A2]](ZIO.fail(e))(ZIO.succeed(_)))
/**
* Emits a sliding window of n elements.
* {{{
* Stream(1, 2, 3, 4).sliding(2).runCollect // Chunk(Chunk(1, 2), Chunk(2, 3), Chunk(3, 4))
* }}}
*/
def sliding(chunkSize0: => Int, stepSize0: Int = 1)(implicit trace: Trace): ZStream[R, E, Chunk[A]] =
ZStream.suspend {
val chunkSize = chunkSize0
val stepSize = stepSize0
def slidingChunk(chunk: Chunk[A], in: Chunk[A]): (Chunk[A], Chunk[Chunk[A]]) = {
val updatedChunk = chunk ++ in
val length = updatedChunk.length
if (length >= chunkSize) {
val array = new Array[Chunk[A]]((length - chunkSize) / stepSize + 1)
var arrayIndex = 0
var chunkIndex = 0
while (chunkIndex + chunkSize <= length) {
array(arrayIndex) = updatedChunk.slice(chunkIndex, chunkIndex + chunkSize)
arrayIndex += 1
chunkIndex += stepSize
}
(updatedChunk.drop(chunkIndex), Chunk.fromArray(array))
} else (updatedChunk, Chunk.empty)
}
def sliding(chunk: Chunk[A], written: Boolean): ZChannel[Any, E, Chunk[A], Any, E, Chunk[Chunk[A]], Any] =
ZChannel.readWithCause(
in => {
val (updatedChunk, out) = slidingChunk(chunk, in)
if (out.isEmpty) sliding(updatedChunk, written)
else ZChannel.write(out) *> sliding(updatedChunk, true)
},
err => {
val index = if (written && chunkSize > stepSize) chunkSize - stepSize else 0
if (index >= chunk.length) ZChannel.refailCause(err)
else ZChannel.write(Chunk.single(chunk)) *> ZChannel.refailCause(err)
},
done => {
val index = if (written && chunkSize > stepSize) chunkSize - stepSize else 0
if (index >= chunk.length) ZChannel.succeedNow(done)
else ZChannel.write(Chunk.single(chunk)) *> ZChannel.succeedNow(done)
}
)
ZStream.fromChannel(self.channel >>> sliding(Chunk.empty, false))
}
/**
* Splits elements based on a predicate.
* {{{
* ZStream.range(1, 10).split(_ % 4 == 0).runCollect // Chunk(Chunk(1, 2, 3), Chunk(5, 6, 7), Chunk(9))
* }}}
*/
def split(f: A => Boolean)(implicit trace: Trace): ZStream[R, E, Chunk[A]] = {
def split(leftovers: Chunk[A])(in: Chunk[A]): ZChannel[R, E, Chunk[A], Any, E, Chunk[Chunk[A]], Any] = {
val (chunk, remaining) = (leftovers ++ in).splitWhere(f)
if (chunk.isEmpty || remaining.isEmpty) loop(chunk ++ remaining.drop(1))
else ZChannel.write(Chunk.single(chunk)) *> split(Chunk.empty)(remaining.drop(1))
}
def loop(leftovers: Chunk[A]): ZChannel[R, E, Chunk[A], Any, E, Chunk[Chunk[A]], Any] =
ZChannel.readWithCause(
(in: Chunk[A]) => split(leftovers)(in),
(e: Cause[E]) => ZChannel.refailCause(e),
(_: Any) => {
if (leftovers.isEmpty) ZChannel.unit
else if (leftovers.find(f).isEmpty) ZChannel.write(Chunk.single(leftovers)) *> ZChannel.unit
else split(Chunk.empty)(leftovers) *> ZChannel.unit
}
)
new ZStream(self.channel >>> loop(Chunk.empty))
}
/**
* Splits elements on a delimiter and transforms the splits into desired
* output.
*/
def splitOnChunk[A1 >: A](delimiter: => Chunk[A1])(implicit trace: Trace): ZStream[R, E, Chunk[A]] =
ZStream.succeed(delimiter).flatMap { delimiter =>
def next(
leftover: Option[Chunk[A]],
delimiterIndex: Int
): ZChannel[R, E, Chunk[A], Any, E, Chunk[Chunk[A]], Any] =
ZChannel.readWithCause(
inputChunk => {
var buffer = null.asInstanceOf[collection.mutable.ArrayBuffer[Chunk[A]]]
inputChunk.foldLeft((leftover getOrElse Chunk.empty, delimiterIndex)) {
case ((carry, delimiterCursor), a) =>
val concatenated = carry :+ a
if (delimiterCursor < delimiter.length && a == delimiter(delimiterCursor)) {
if (delimiterCursor + 1 == delimiter.length) {
if (buffer eq null) buffer = collection.mutable.ArrayBuffer[Chunk[A]]()
buffer += concatenated.take(concatenated.length - delimiter.length)
(Chunk.empty, 0)
} else (concatenated, delimiterCursor + 1)
} else (concatenated, if (a == delimiter(0)) 1 else 0)
} match {
case (carry, delimiterCursor) =>
ZChannel.write(
if (buffer eq null) Chunk.empty
else Chunk.fromArray(buffer.toArray)
) *> next(if (carry.nonEmpty) Some(carry) else None, delimiterCursor)
}
},
halt =>
leftover match {
case Some(chunk) => ZChannel.write(Chunk.single(chunk)) *> ZChannel.refailCause(halt)
case None => ZChannel.refailCause(halt)
},
done =>
leftover match {
case Some(chunk) => ZChannel.write(Chunk.single(chunk)) *> ZChannel.succeed(done)
case None => ZChannel.succeed(done)
}
)
new ZStream(self.channel >>> next(None, 0))
}
/**
* Takes the specified number of elements from this stream.
*/
def take(n: => Long)(implicit trace: Trace): ZStream[R, E, A] =
self >>> ZPipeline.take(n)
/**
* Takes the last specified number of elements from this stream.
*/
def takeRight(n: => Int)(implicit trace: Trace): ZStream[R, E, A] =
ZStream.succeed(n).flatMap { n =>
if (n <= 0) ZStream.empty
else
new ZStream(
ZChannel.unwrap(
for {
queue <- ZIO.succeed(SingleThreadedRingBuffer[A](n))
} yield {
lazy val reader: ZChannel[Any, E, Chunk[A], Any, E, Chunk[A], Unit] = ZChannel.readWithCause(
(in: Chunk[A]) => {
in.foreach(queue.put)
reader
},
ZChannel.refailCause,
(_: Any) => ZChannel.write(queue.toChunk) *> ZChannel.unit
)
(self.channel >>> reader)
}
)
)
}
/**
* Takes all elements of the stream until the specified predicate evaluates to
* `true`.
*/
def takeUntil(f: A => Boolean)(implicit trace: Trace): ZStream[R, E, A] =
self >>> ZPipeline.takeUntil(f)
/**
* Takes all elements of the stream until the specified effectual predicate
* evaluates to `true`.
*/
def takeUntilZIO[R1 <: R, E1 >: E](
f: A => ZIO[R1, E1, Boolean]
)(implicit trace: Trace): ZStream[R1, E1, A] =
self >>> ZPipeline.takeUntilZIO(f)
/**
* Takes all elements of the stream for as long as the specified predicate
* evaluates to `true`.
*/
def takeWhile(f: A => Boolean)(implicit trace: Trace): ZStream[R, E, A] =
self >>> ZPipeline.takeWhile(f)
/**
* Takes all elements of the stream for as long as the specified effectual
* predicate evaluates to `true`.
*/
def takeWhileZIO[R1 <: R, E1 >: E](f: A => ZIO[R1, E1, Boolean])(implicit trace: Trace): ZStream[R1, E1, A] =
self >>> ZPipeline.takeWhileZIO(f)
/**
* Adds an effect to consumption of every element of the stream.
*/
def tap[R1 <: R, E1 >: E](f: A => ZIO[R1, E1, Any])(implicit trace: Trace): ZStream[R1, E1, A] =
mapZIO(a => f(a).as(a))
/**
* Returns a stream that effectfully "peeks" at the failure and adds an effect
* to consumption of every element of the stream
*/
def tapBoth[R1 <: R, E1 >: E](
f: E => ZIO[R1, E1, Any],
g: A => ZIO[R1, E1, Any]
)(implicit ev: CanFail[E], trace: Trace): ZStream[R1, E1, A] =
tapError(f).tap(g)
/**
* Returns a stream that effectfully "peeks" at the failure of the stream.
*/
def tapError[R1 <: R, E1 >: E](
f: E => ZIO[R1, E1, Any]
)(implicit ev: CanFail[E], trace: Trace): ZStream[R1, E1, A] =
tapErrorCause(_.failureOrCause.fold(f, _ => ZIO.unit))
/**
* Returns a stream that effectfully "peeks" at the cause of failure of the
* stream.
*/
def tapErrorCause[R1 <: R, E1 >: E](
f: Cause[E] => ZIO[R1, E1, Any]
)(implicit ev: CanFail[E], trace: Trace): ZStream[R1, E1, A] = {
lazy val tapErrorCause: ZChannel[R1, E, Chunk[A], Any, E1, Chunk[A], Any] =
ZChannel.readWithCause(
chunk => ZChannel.write(chunk) *> tapErrorCause,
cause => ZChannel.fromZIO(f(cause)) *> ZChannel.refailCause(cause),
done => ZChannel.succeedNow(done)
)
new ZStream(self.channel.pipeTo(tapErrorCause))
}
/**
* Sends all elements emitted by this stream to the specified sink in addition
* to emitting them.
*/
def tapSink[R1 <: R, E1 >: E](
sink: => ZSink[R1, E1, A, Any, Any]
)(implicit trace: Trace): ZStream[R1, E1, A] =
ZStream.fromZIO(Queue.bounded[Take[E1, A]](1) <*> Promise.make[Nothing, Unit]).flatMap { case (queue, promise) =>
val right = ZStream.fromQueue(queue, 1).flattenTake
lazy val loop: ZChannel[R1, E, Chunk[A], Any, E1, Chunk[A], Any] =
ZChannel.readWithCause(
chunk =>
ZChannel
.fromZIO(queue.offer(Take.chunk(chunk)))
.foldCauseChannel(
_ => ZChannel.write(chunk) *> ZChannel.identity,
_ => ZChannel.write(chunk) *> loop
),
cause =>
ZChannel
.fromZIO(queue.offer(Take.failCause(cause)))
.foldCauseChannel(
_ => ZChannel.refailCause(cause),
_ => ZChannel.refailCause(cause)
),
_ =>
ZChannel
.fromZIO(queue.offer(Take.end))
.foldCauseChannel(
_ => ZChannel.unit,
_ => ZChannel.unit
)
)
new ZStream(
ZChannel.fromZIO(promise.await) *> self.channel
.pipeTo(loop)
.ensuring(queue.offer(Take.end).forkDaemon *> queue.awaitShutdown) *> ZChannel.unit
)
.merge(ZStream.execute((promise.succeed(()) *> right.run(sink)).ensuring(queue.shutdown)), HaltStrategy.Both)
}
/**
* Throttles the chunks of this stream according to the given bandwidth
* parameters using the token bucket algorithm. Allows for burst in the
* processing of elements by allowing the token bucket to accumulate tokens up
* to a `units + burst` threshold. Chunks that do not meet the bandwidth
* constraints are dropped. The weight of each chunk is determined by the
* `costFn` function.
*/
def throttleEnforce(units: => Long, duration: => Duration, burst: => Long = 0)(
costFn: Chunk[A] => Long
)(implicit trace: Trace): ZStream[R, E, A] =
self >>> ZPipeline.throttleEnforce(units, duration, burst)(costFn)
/**
* Throttles the chunks of this stream according to the given bandwidth
* parameters using the token bucket algorithm. Allows for burst in the
* processing of elements by allowing the token bucket to accumulate tokens up
* to a `units + burst` threshold. Chunks that do not meet the bandwidth
* constraints are dropped. The weight of each chunk is determined by the
* `costFn` effectful function.
*/
def throttleEnforceZIO[R1 <: R, E1 >: E](units: => Long, duration: => Duration, burst: => Long = 0)(
costFn: Chunk[A] => ZIO[R1, E1, Long]
)(implicit trace: Trace): ZStream[R1, E1, A] =
self >>> ZPipeline.throttleEnforceZIO(units, duration, burst)(costFn)
/**
* Delays the chunks of this stream according to the given bandwidth
* parameters using the token bucket algorithm. Allows for burst in the
* processing of elements by allowing the token bucket to accumulate tokens up
* to a `units + burst` threshold. The weight of each chunk is determined by
* the `costFn` function.
*/
def throttleShape(units: => Long, duration: => Duration, burst: => Long = 0)(
costFn: Chunk[A] => Long
)(implicit trace: Trace): ZStream[R, E, A] =
self >>> ZPipeline.throttleShape(units, duration, burst)(costFn)
/**
* Delays the chunks of this stream according to the given bandwidth
* parameters using the token bucket algorithm. Allows for burst in the
* processing of elements by allowing the token bucket to accumulate tokens up
* to a `units + burst` threshold. The weight of each chunk is determined by
* the `costFn` effectful function.
*/
def throttleShapeZIO[R1 <: R, E1 >: E](units: => Long, duration: => Duration, burst: => Long = 0)(
costFn: Chunk[A] => ZIO[R1, E1, Long]
)(implicit trace: Trace): ZStream[R1, E1, A] =
self >>> ZPipeline.throttleShapeZIO(units, duration, burst)(costFn)
/**
* Ends the stream if it does not produce a value after d duration.
*/
def timeout(d: => Duration)(implicit trace: Trace): ZStream[R, E, A] =
ZStream.succeed(d).flatMap { d =>
ZStream.fromPull[R, E, A] {
self.toPull.map { pull =>
// None case on the error channel of pull indicates completion/done.
// Move it to success channel before calling timeout effect so that it does not log completion as failure.
// In the end, move None case back to error channel for further stream processing
pull.unsome.timeoutTo(None)(identity)(d).some
}
}
}
/**
* Fails the stream with given error if it does not produce a value after d
* duration.
*/
def timeoutFail[E1 >: E](e: => E1)(d: Duration)(implicit
trace: Trace
): ZStream[R, E1, A] =
self.timeoutTo[R, E1, A](d)(ZStream.fail(e))
/**
* Fails the stream with given cause if it does not produce a value after d
* duration.
*/
def timeoutFailCause[E1 >: E](
cause: => Cause[E1]
)(d: => Duration)(implicit trace: Trace): ZStream[R, E1, A] =
ZStream.succeed((cause, d)).flatMap { case (cause, d) =>
ZStream.fromPull[R, E1, A] {
self.toPull.map { pull =>
// None case on the error channel of pull indicates completion/done.
// Move it to success channel before calling timeout effect so that it does not log completion as failure.
// In the end, move None case back to error channel for further stream processing
pull.unsome.timeoutFailCause(cause)(d).some
}
}
}
/**
* Switches the stream if it does not produce a value after d duration.
*/
def timeoutTo[R1 <: R, E1 >: E, A2 >: A](
d: => Duration
)(that: => ZStream[R1, E1, A2])(implicit trace: Trace): ZStream[R1, E1, A2] = {
final case class StreamTimeout() extends Throwable
self.timeoutFailCause(Cause.die(StreamTimeout()))(d).catchSomeCause { case Cause.Die(StreamTimeout(), _) => that }
}
/** Converts the stream to its underlying channel */
def toChannel: ZChannel[R, Any, Any, Any, E, Chunk[A], Any] =
self.channel
/**
* Converts the stream to a scoped hub of chunks. After the scope is closed,
* the hub will never again produce values and should be discarded.
*/
def toHub[E1 >: E, A1 >: A](
capacity: => Int
)(implicit trace: Trace): ZIO[R with Scope, Nothing, Hub[Take[E1, A1]]] =
for {
hub <- ZIO.acquireRelease(Hub.bounded[Take[E1, A1]](capacity))(_.shutdown)
_ <- self.runIntoHubScoped(hub).forkScoped
} yield hub
/**
* Converts this stream of bytes into a `java.io.InputStream` wrapped in a
* scoped [[ZIO]]. The returned input stream will only be valid within the
* scope.
*/
def toInputStream(implicit
ev0: E <:< Throwable,
ev1: A <:< Byte,
trace: Trace
): ZIO[R with Scope, E, java.io.InputStream] =
for {
runtime <- ZIO.runtime[R]
pull <- toPull.asInstanceOf[ZIO[R with Scope, Nothing, ZIO[R, Option[Throwable], Chunk[Byte]]]]
} yield ZInputStream.fromPull(runtime, pull)
/**
* Converts this stream into a `scala.collection.Iterator` wrapped in a scoped
* [[ZIO]]. The returned iterator will only be valid within the scope.
*/
def toIterator(implicit trace: Trace): ZIO[R with Scope, Nothing, Iterator[Either[E, A]]] =
for {
runtime <- ZIO.runtime[R]
pull <- toPull
} yield {
def unfoldPull: Iterator[Either[E, A]] =
runtime.unsafe.run(pull)(trace, Unsafe.unsafe) match {
case Exit.Success(chunk) => chunk.iterator.map(Right(_)) ++ unfoldPull
case Exit.Failure(cause) =>
cause.failureOrCause match {
case Left(None) => Iterator.empty
case Left(Some(e)) => Iterator.single(Left(e))
case Right(c) => throw FiberFailure(c)
}
}
unfoldPull
}
/**
* Returns in a scope a ZIO effect that can be used to repeatedly pull chunks
* from the stream. The pull effect fails with None when the stream is
* finished, or with Some error if it fails, otherwise it returns a chunk of
* the stream's output.
*/
def toPull(implicit trace: Trace): ZIO[R with Scope, Nothing, ZIO[R, Option[E], Chunk[A]]] =
channel.toPull.map { pull =>
pull.mapError(error => Some(error)).flatMap {
case Left(done) => ZIO.fail(None)
case Right(elem) => ZIO.succeed(elem)
}
}
/**
* Converts this stream of chars into a `java.io.Reader` wrapped in a scoped
* [[ZIO]]. The returned reader will only be valid within the scope.
*/
def toReader(implicit
ev0: E <:< Throwable,
ev1: A <:< Char,
trace: Trace
): ZIO[R with Scope, E, java.io.Reader] =
for {
runtime <- ZIO.runtime[R]
pull <- toPull.asInstanceOf[ZIO[R with Scope, Nothing, ZIO[R, Option[Throwable], Chunk[Char]]]]
} yield ZReader.fromPull(runtime, pull)
/**
* Converts the stream to a scoped queue of chunks. After the scope is closed,
* the queue will never again produce values and should be discarded.
*/
def toQueue(
capacity: => Int = 2
)(implicit trace: Trace): ZIO[R with Scope, Nothing, Dequeue[Take[E, A]]] =
for {
queue <- ZIO.acquireRelease(Queue.bounded[Take[E, A]](capacity))(_.shutdown)
_ <- self.runIntoQueueScoped(queue).forkScoped
} yield queue
/**
* Converts the stream to a dropping scoped queue of chunks. After the scope
* is closed, the queue will never again produce values and should be
* discarded.
*/
def toQueueDropping(
capacity: => Int = 2
)(implicit trace: Trace): ZIO[R with Scope, Nothing, Dequeue[Take[E, A]]] =
for {
queue <- ZIO.acquireRelease(Queue.dropping[Take[E, A]](capacity))(_.shutdown)
_ <- self.runIntoQueueScoped(queue).forkScoped
} yield queue
/**
* Converts the stream to a scoped queue of elements. After the scope is
* closed, the queue will never again produce values and should be discarded.
*/
def toQueueOfElements(
capacity: => Int = 2
)(implicit trace: Trace): ZIO[R with Scope, Nothing, Dequeue[Exit[Option[E], A]]] =
for {
queue <- ZIO.acquireRelease(Queue.bounded[Exit[Option[E], A]](capacity))(_.shutdown)
_ <- self.runIntoQueueElementsScoped(queue).forkScoped
} yield queue
/**
* Converts the stream to a sliding scoped queue of chunks. After the scope is
* closed, the queue will never again produce values and should be discarded.
*/
def toQueueSliding(
capacity: => Int = 2
)(implicit trace: Trace): ZIO[R with Scope, Nothing, Dequeue[Take[E, A]]] =
for {
queue <- ZIO.acquireRelease(Queue.sliding[Take[E, A]](capacity))(_.shutdown)
_ <- self.runIntoQueueScoped(queue).forkScoped
} yield queue
/**
* Converts the stream into an unbounded scoped queue. After the scope is
* closed, the queue will never again produce values and should be discarded.
*/
def toQueueUnbounded(implicit trace: Trace): ZIO[R with Scope, Nothing, Dequeue[Take[E, A]]] =
for {
queue <- ZIO.acquireRelease(Queue.unbounded[Take[E, A]])(_.shutdown)
_ <- self.runIntoQueueScoped(queue).forkScoped
} yield queue
/**
* Applies the transducer to the stream and emits its outputs.
*/
def transduce[R1 <: R, E1 >: E, A1 >: A, Z](
sink: => ZSink[R1, E1, A1, A1, Z]
)(implicit trace: Trace): ZStream[R1, E1, Z] =
self >>> ZPipeline.fromSink(sink)
/**
* Updates a service in the environment of this effect.
*/
def updateService[M] =
new ZStream.UpdateService[R, E, A, M](self)
/**
* Updates a service at the specified key in the environment of this effect.
*/
def updateServiceAt[Service]: ZStream.UpdateServiceAt[R, E, A, Service] =
new ZStream.UpdateServiceAt[R, E, A, Service](self)
/**
* Threads the stream through a transformation pipeline.
*/
def via[R1 <: R, E1 >: E, B](pipeline: => ZPipeline[R1, E1, A, B])(implicit
trace: Trace
): ZStream[R1, E1, B] =
ZStream.suspend(pipeline(self))
/**
* Threads the stream through the transformation function `f`.
*/
def viaFunction[R2, E2, B](f: ZStream[R, E, A] => ZStream[R2, E2, B])(implicit
trace: Trace
): ZStream[R2, E2, B] =
f(self)
/**
* Returns this stream if the specified condition is satisfied, otherwise
* returns an empty stream.
*/
def when(b: => Boolean)(implicit trace: Trace): ZStream[R, E, A] =
ZStream.when(b)(self)
/**
* Returns this stream if the specified effectful condition is satisfied,
* otherwise returns an empty stream.
*/
def whenZIO[R1 <: R, E1 >: E](b: => ZIO[R1, E1, Boolean])(implicit trace: Trace): ZStream[R1, E1, A] =
ZStream.whenZIO(b)(self)
/**
* Equivalent to [[filter]] but enables the use of filter clauses in
* for-comprehensions
*/
def withFilter(predicate: A => Boolean)(implicit trace: Trace): ZStream[R, E, A] =
filter(predicate)
/**
* Zips this stream with another point-wise and emits tuples of elements from
* both streams.
*
* The new stream will end when one of the sides ends.
*/
def zip[R1 <: R, E1 >: E, A2](that: => ZStream[R1, E1, A2])(implicit
zippable: Zippable[A, A2],
trace: Trace
): ZStream[R1, E1, zippable.Out] =
zipWith(that)(zippable.zip(_, _))
/**
* Zips this stream with another point-wise, creating a new stream of pairs of
* elements from both sides.
*
* The defaults `defaultLeft` and `defaultRight` will be used if the streams
* have different lengths and one of the streams has ended before the other.
*/
def zipAll[R1 <: R, E1 >: E, A1 >: A, A2](
that: => ZStream[R1, E1, A2]
)(defaultLeft: => A1, defaultRight: => A2)(implicit trace: Trace): ZStream[R1, E1, (A1, A2)] =
zipAllWith(that)((_, defaultRight), (defaultLeft, _))((_, _))
/**
* Zips this stream with another point-wise, and keeps only elements from this
* stream.
*
* The provided default value will be used if the other stream ends before
* this one.
*/
def zipAllLeft[R1 <: R, E1 >: E, A1 >: A, A2](that: => ZStream[R1, E1, A2])(default: => A1)(implicit
trace: Trace
): ZStream[R1, E1, A1] =
zipAllWith(that)(identity, _ => default)((o, _) => o)
/**
* Zips this stream with another point-wise, and keeps only elements from the
* other stream.
*
* The provided default value will be used if this stream ends before the
* other one.
*/
def zipAllRight[R1 <: R, E1 >: E, A2](that: => ZStream[R1, E1, A2])(default: => A2)(implicit
trace: Trace
): ZStream[R1, E1, A2] =
zipAllWith(that)(_ => default, identity)((_, A2) => A2)
/**
* Zips this stream with another point-wise. The provided functions will be
* used to create elements for the composed stream.
*
* The functions `left` and `right` will be used if the streams have different
* lengths and one of the streams has ended before the other.
*/
def zipAllWith[R1 <: R, E1 >: E, A2, A3](
that: => ZStream[R1, E1, A2]
)(left: A => A3, right: A2 => A3)(both: (A, A2) => A3)(implicit trace: Trace): ZStream[R1, E1, A3] = {
sealed trait State[+A, +A2]
case object DrainLeft extends State[Nothing, Nothing]
case object DrainRight extends State[Nothing, Nothing]
case object PullBoth extends State[Nothing, Nothing]
final case class PullLeft[A2](rightChunk: Chunk[A2]) extends State[Nothing, A2]
final case class PullRight[A](leftChunk: Chunk[A]) extends State[A, Nothing]
def pull(
state: State[A, A2],
pullLeft: ZIO[R, Option[E], Chunk[A]],
pullRight: ZIO[R1, Option[E1], Chunk[A2]]
): ZIO[R1, Nothing, Exit[Option[E1], (Chunk[A3], State[A, A2])]] =
state match {
case DrainLeft =>
pullLeft.foldZIO(
err => ZIO.succeed(Exit.fail(err)),
leftChunk => ZIO.succeed(Exit.succeed(leftChunk.map(left) -> DrainLeft))
)
case DrainRight =>
pullRight.foldZIO(
err => ZIO.succeed(Exit.fail(err)),
rightChunk => ZIO.succeed(Exit.succeed(rightChunk.map(right) -> DrainRight))
)
case PullBoth =>
pullLeft.unsome
.zipPar(pullRight.unsome)
.foldZIO(
err => ZIO.succeed(Exit.fail(Some(err))),
{
case (Some(leftChunk), Some(rightChunk)) =>
if (leftChunk.isEmpty && rightChunk.isEmpty)
pull(PullBoth, pullLeft, pullRight)
else if (leftChunk.isEmpty)
pull(PullLeft(rightChunk), pullLeft, pullRight)
else if (rightChunk.isEmpty)
pull(PullRight(leftChunk), pullLeft, pullRight)
else
ZIO.succeed(Exit.succeed(zipWithChunks(leftChunk, rightChunk, both)))
case (Some(leftChunk), None) =>
ZIO.succeed(Exit.succeed(leftChunk.map(left) -> DrainLeft))
case (None, Some(rightChunk)) =>
ZIO.succeed(Exit.succeed(rightChunk.map(right) -> DrainRight))
case (None, None) =>
ZIO.succeed(Exit.fail(None))
}
)
case PullLeft(rightChunk) =>
pullLeft.foldZIO(
{
case Some(err) => ZIO.succeed(Exit.fail(Some(err)))
case None => ZIO.succeed(Exit.succeed(rightChunk.map(right) -> DrainRight))
},
leftChunk =>
if (leftChunk.isEmpty)
pull(PullLeft(rightChunk), pullLeft, pullRight)
else if (rightChunk.isEmpty)
pull(PullRight(leftChunk), pullLeft, pullRight)
else
ZIO.succeed(Exit.succeed(zipWithChunks(leftChunk, rightChunk, both)))
)
case PullRight(leftChunk) =>
pullRight.foldZIO(
{
case Some(err) => ZIO.succeed(Exit.fail(Some(err)))
case None => ZIO.succeed(Exit.succeed(leftChunk.map(left) -> DrainLeft))
},
rightChunk =>
if (rightChunk.isEmpty)
pull(PullRight(leftChunk), pullLeft, pullRight)
else if (leftChunk.isEmpty)
pull(PullLeft(rightChunk), pullLeft, pullRight)
else
ZIO.succeed(Exit.succeed(zipWithChunks(leftChunk, rightChunk, both)))
)
}
def zipWithChunks(
leftChunk: Chunk[A],
rightChunk: Chunk[A2],
f: (A, A2) => A3
): (Chunk[A3], State[A, A2]) =
zipChunks(leftChunk, rightChunk, f) match {
case (out, Left(leftChunk)) =>
if (leftChunk.isEmpty)
out -> PullBoth
else
out -> PullRight(leftChunk)
case (out, Right(rightChunk)) =>
if (rightChunk.isEmpty)
out -> PullBoth
else
out -> PullLeft(rightChunk)
}
self.combineChunks[R1, E1, State[A, A2], A2, A3](that)(PullBoth)(pull)
}
/**
* Zips the two streams so that when a value is emitted by either of the two
* streams, it is combined with the latest value from the other stream to
* produce a result.
*
* Note: tracking the latest value is done on a per-chunk basis. That means
* that emitted elements that are not the last value in chunks will never be
* used for zipping.
*/
def zipLatest[R1 <: R, E1 >: E, A2, A3](
that: => ZStream[R1, E1, A2]
)(implicit zippable: Zippable[A, A2], trace: Trace): ZStream[R1, E1, zippable.Out] =
self.zipLatestWith(that)(zippable.zip(_, _))
/**
* Zips the two streams so that when a value is emitted by either of the two
* streams, it is combined with the latest value from the other stream to
* produce a result.
*
* Note: tracking the latest value is done on a per-chunk basis. That means
* that emitted elements that are not the last value in chunks will never be
* used for zipping.
*/
def zipLatestWith[R1 <: R, E1 >: E, A2, A3](
that: => ZStream[R1, E1, A2]
)(f: (A, A2) => A3)(implicit trace: Trace): ZStream[R1, E1, A3] = {
def pullNonEmpty[R, E, O](pull: ZIO[R, Option[E], Chunk[O]]): ZIO[R, Option[E], Chunk[O]] =
pull.flatMap(chunk => if (chunk.isEmpty) pullNonEmpty(pull) else ZIO.succeed(chunk))
ZStream.fromPull[R1, E1, A3] {
for {
left <- self.toPull.map(pullNonEmpty(_))
right <- that.toPull.map(pullNonEmpty(_))
pull <- (ZStream.fromZIOOption {
left.raceWith(right)(
(leftDone, rightFiber) => ZIO.done(leftDone).zipWith(rightFiber.join)((_, _, true)),
(rightDone, leftFiber) => ZIO.done(rightDone).zipWith(leftFiber.join)((r, l) => (l, r, false))
)
}.flatMap { case (l, r, leftFirst) =>
ZStream.fromZIO(Ref.make(l(l.size - 1) -> r(r.size - 1))).flatMap { latest =>
ZStream.fromChunk(
if (leftFirst) r.map(f(l(l.size - 1), _))
else l.map(f(_, r(r.size - 1)))
) ++
ZStream
.repeatZIOOption(left)
.mergeEither(ZStream.repeatZIOOption(right))
.mapZIO {
case Left(leftChunk) =>
latest.modify { case (_, rightLatest) =>
(leftChunk.map(f(_, rightLatest)), (leftChunk(leftChunk.size - 1), rightLatest))
}
case Right(rightChunk) =>
latest.modify { case (leftLatest, _) =>
(rightChunk.map(f(leftLatest, _)), (leftLatest, rightChunk(rightChunk.size - 1)))
}
}
.flatMap(ZStream.fromChunk(_))
}
}).toPull
} yield pull
}
}
/**
* Zips this stream with another point-wise, but keeps only the outputs of
* this stream.
*
* The new stream will end when one of the sides ends.
*/
def zipLeft[R1 <: R, E1 >: E, A2](that: => ZStream[R1, E1, A2])(implicit trace: Trace): ZStream[R1, E1, A] =
zipWithChunks(that)((cl, cr) =>
if (cl.size > cr.size)
(cl.take(cr.size), Left(cl.drop(cr.size)))
else
(cl, Right(cr.drop(cl.size)))
)
/**
* Zips this stream with another point-wise, but keeps only the outputs of the
* other stream.
*
* The new stream will end when one of the sides ends.
*/
def zipRight[R1 <: R, E1 >: E, A2](that: => ZStream[R1, E1, A2])(implicit trace: Trace): ZStream[R1, E1, A2] =
zipWithChunks(that)((cl, cr) =>
if (cl.size > cr.size)
(cr, Left(cl.drop(cr.size)))
else
(cr.take(cl.size), Right(cr.drop(cl.size)))
)
/**
* Zips this stream with another point-wise and applies the function to the
* paired elements.
*
* The new stream will end when one of the sides ends.
*/
def zipWith[R1 <: R, E1 >: E, A2, A3](
that: => ZStream[R1, E1, A2]
)(f: (A, A2) => A3)(implicit trace: Trace): ZStream[R1, E1, A3] =
zipWithChunks(that)(zipChunks(_, _, f))
/**
* Zips this stream with another point-wise and applies the function to the
* paired elements.
*
* The new stream will end when one of the sides ends.
*/
def zipWithChunks[R1 <: R, E1 >: E, A1 >: A, A2, A3](
that: => ZStream[R1, E1, A2]
)(
f: (Chunk[A1], Chunk[A2]) => (Chunk[A3], Either[Chunk[A1], Chunk[A2]])
)(implicit trace: Trace): ZStream[R1, E1, A3] = {
sealed trait State[+A1, +A2]
case object PullBoth extends State[Nothing, Nothing]
final case class PullLeft[A2](rightChunk: Chunk[A2]) extends State[Nothing, A2]
final case class PullRight[A1](leftChunk: Chunk[A1]) extends State[A1, Nothing]
def pull(
state: State[A1, A2],
pullLeft: ZIO[R, Option[E], Chunk[A1]],
pullRight: ZIO[R1, Option[E1], Chunk[A2]]
): ZIO[R1, Nothing, Exit[Option[E1], (Chunk[A3], State[A1, A2])]] =
state match {
case PullBoth =>
pullLeft.unsome
.zipPar(pullRight.unsome)
.foldZIO(
err => ZIO.succeed(Exit.fail(Some(err))),
{
case (Some(leftChunk), Some(rightChunk)) =>
if (leftChunk.isEmpty && rightChunk.isEmpty)
pull(PullBoth, pullLeft, pullRight)
else if (leftChunk.isEmpty)
pull(PullLeft(rightChunk), pullLeft, pullRight)
else if (rightChunk.isEmpty)
pull(PullRight(leftChunk), pullLeft, pullRight)
else
ZIO.succeed(Exit.succeed(zipWithChunks(leftChunk, rightChunk)))
case _ => ZIO.succeed(Exit.fail(None))
}
)
case PullLeft(rightChunk) =>
pullLeft.foldZIO(
err => ZIO.succeed(Exit.fail(err)),
leftChunk =>
if (leftChunk.isEmpty)
pull(PullLeft(rightChunk), pullLeft, pullRight)
else if (rightChunk.isEmpty)
pull(PullRight(leftChunk), pullLeft, pullRight)
else
ZIO.succeed(Exit.succeed(zipWithChunks(leftChunk, rightChunk)))
)
case PullRight(leftChunk) =>
pullRight.foldZIO(
err => ZIO.succeed(Exit.fail(err)),
rightChunk =>
if (rightChunk.isEmpty)
pull(PullRight(leftChunk), pullLeft, pullRight)
else if (leftChunk.isEmpty)
pull(PullLeft(rightChunk), pullLeft, pullRight)
else
ZIO.succeed(Exit.succeed(zipWithChunks(leftChunk, rightChunk)))
)
}
def zipWithChunks(
leftChunk: Chunk[A1],
rightChunk: Chunk[A2]
): (Chunk[A3], State[A1, A2]) =
f(leftChunk, rightChunk) match {
case (out, Left(leftChunk)) =>
if (leftChunk.isEmpty)
out -> PullBoth
else
out -> PullRight(leftChunk)
case (out, Right(rightChunk)) =>
if (rightChunk.isEmpty)
out -> PullBoth
else
out -> PullLeft(rightChunk)
}
self.combineChunks[R1, E1, State[A1, A2], A2, A3](that)(PullBoth)(pull)
}
/**
* Zips this stream together with the index of elements.
*/
def zipWithIndex(implicit trace: Trace): ZStream[R, E, (A, Long)] =
mapAccum(0L)((index, a) => (index + 1, (a, index)))
/**
* Zips the two streams so that when a value is emitted by either of the two
* streams, it is combined with the latest value from the other stream to
* produce a result.
*
* Note: tracking the latest value is done on a per-chunk basis. That means
* that emitted elements that are not the last value in chunks will never be
* used for zipping.
*/
@deprecated("use zipLatestWith", "2.0.3")
def zipWithLatest[R1 <: R, E1 >: E, A2, A3](
that: => ZStream[R1, E1, A2]
)(f: (A, A2) => A3)(implicit trace: Trace): ZStream[R1, E1, A3] =
zipLatestWith(that)(f)
/**
* Zips each element with the next element if present.
*/
def zipWithNext(implicit trace: Trace): ZStream[R, E, (A, Option[A])] =
self >>> ZPipeline.zipWithNext[A]
/**
* Zips each element with the previous element. Initially accompanied by
* `None`.
*/
def zipWithPrevious(implicit trace: Trace): ZStream[R, E, (Option[A], A)] =
self >>> ZPipeline.zipWithPrevious
/**
* Zips each element with both the previous and next element.
*/
def zipWithPreviousAndNext(implicit trace: Trace): ZStream[R, E, (Option[A], A, Option[A])] =
self >>> ZPipeline.zipWithPreviousAndNext
}
object ZStream extends ZStreamPlatformSpecificConstructors {
/**
* The default chunk size used by the various combinators and constructors of
* [[ZStream]].
*/
final val DefaultChunkSize = 4096
/**
* Submerges the error case of an `Either` into the `ZStream`.
*/
def absolve[R, E, O](xs: ZStream[R, E, Either[E, O]])(implicit trace: Trace): ZStream[R, E, O] = {
lazy val loop: ZChannel[Any, E, Chunk[Either[E, O]], Any, E, Chunk[O], Any] = ZChannel.readWithCause(
(in: Chunk[Either[E, O]]) => {
val mapped = in.collectWhile { case Right(o) => o }
if (mapped.size == in.size) ZChannel.write(mapped) *> loop
else {
val firstError = in(mapped.size).asInstanceOf[Left[E, O]]
ZChannel.write(mapped) *> ZChannel.fail(firstError.value)
}
},
(cause: Cause[E]) => ZChannel.refailCause(cause),
(_: Any) => ZChannel.unit
)
xs.pipeThroughChannel(loop)
}
/**
* Creates a stream from a single value that will get cleaned up after the
* stream is consumed
*/
def acquireReleaseWith[R, E, A](acquire: => ZIO[R, E, A])(release: A => URIO[R, Any])(implicit
trace: Trace
): ZStream[R, E, A] =
scoped[R](ZIO.acquireRelease(acquire)(release))
/**
* Creates a stream from a single value that will get cleaned up after the
* stream is consumed
*/
def acquireReleaseExitWith[R, E, A](
acquire: => ZIO[R, E, A]
)(release: (A, Exit[Any, Any]) => URIO[R, Any])(implicit trace: Trace): ZStream[R, E, A] =
scoped[R](ZIO.acquireReleaseExit(acquire)(release))
/**
* An infinite stream of random alphanumeric characters.
*/
def alphanumeric(implicit trace: Trace): ZStream[Any, Nothing, Char] =
ZStream.repeatZIO {
val chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
Random.nextIntBounded(chars.length).map(chars.charAt)
}
/**
* Creates a pure stream from a variable list of values
*/
def apply[A](as: A*)(implicit trace: Trace): ZStream[Any, Nothing, A] = fromIterable(as)
/**
* Locks the execution of the specified stream to the blocking executor. Any
* streams that are composed after this one will automatically be shifted back
* to the previous executor.
*/
def blocking[R, E, A](stream: => ZStream[R, E, A])(implicit trace: Trace): ZStream[R, E, A] =
ZStream.fromZIO(ZIO.blockingExecutor).flatMap(stream.onExecutor(_))
/**
* Concatenates all of the streams in the chunk to one stream.
*/
def concatAll[R, E, O](streams: => Chunk[ZStream[R, E, O]])(implicit trace: Trace): ZStream[R, E, O] =
ZStream.suspend(streams.foldLeft[ZStream[R, E, O]](empty)(_ ++ _))
/**
* Prints the specified message to the console for debugging purposes.
*/
def debug(value: => Any)(implicit trace: Trace): ZStream[Any, Nothing, Unit] =
ZStream.fromZIO(ZIO.debug(value))
/**
* The stream that dies with the `ex`.
*/
def die(ex: => Throwable)(implicit trace: Trace): ZStream[Any, Nothing, Nothing] =
fromZIO(ZIO.die(ex))
/**
* The stream that dies with an exception described by `msg`.
*/
def dieMessage(msg: => String)(implicit trace: Trace): ZStream[Any, Nothing, Nothing] =
fromZIO(ZIO.dieMessage(msg))
/**
* The stream that ends with the [[zio.Exit]] value `exit`.
*/
def done[E, A](exit: => Exit[E, A])(implicit trace: Trace): ZStream[Any, E, A] =
fromZIO(ZIO.done(exit))
/**
* The empty stream
*/
def empty(implicit trace: Trace): ZStream[Any, Nothing, Nothing] =
new ZStream(ZChannel.unit)
/**
* Accesses the whole environment of the stream.
*/
def environment[R](implicit trace: Trace): ZStream[R, Nothing, ZEnvironment[R]] =
fromZIO(ZIO.environment[R])
/**
* Accesses the environment of the stream.
*/
def environmentWith[R]: EnvironmentWithPartiallyApplied[R] =
new EnvironmentWithPartiallyApplied[R]
/**
* Accesses the environment of the stream in the context of an effect.
*/
def environmentWithZIO[R]: EnvironmentWithZIOPartiallyApplied[R] =
new EnvironmentWithZIOPartiallyApplied[R]
/**
* Accesses the environment of the stream in the context of a stream.
*/
def environmentWithStream[R]: EnvironmentWithStreamPartiallyApplied[R] =
new EnvironmentWithStreamPartiallyApplied[R]
/**
* Creates a stream that executes the specified effect but emits no elements.
*/
def execute[R, E](zio: => ZIO[R, E, Any])(implicit trace: Trace): ZStream[R, E, Nothing] =
ZStream.fromZIO(zio).drain
/**
* The stream that always fails with the `error`
*/
def fail[E](error: => E)(implicit trace: Trace): ZStream[Any, E, Nothing] =
fromZIO(ZIO.fail(error))
/**
* The stream that always fails with `cause`.
*/
def failCause[E](cause: => Cause[E])(implicit trace: Trace): ZStream[Any, E, Nothing] =
fromZIO(Exit.failCause(cause))
/**
* Creates a one-element stream that never fails and executes the finalizer
* when it ends.
*/
def finalizer[R](finalizer: => URIO[R, Any])(implicit trace: Trace): ZStream[R, Nothing, Any] =
acquireReleaseWith[R, Nothing, Unit](ZIO.unit)(_ => finalizer)
def from[Input](
input: => Input
)(implicit constructor: ZStreamConstructor[Input], trace: Trace): constructor.Out =
constructor.make(input)
/**
* Creates a stream from a [[zio.stream.ZChannel]]
*/
def fromChannel[R, E, A](channel: ZChannel[R, Any, Any, Any, E, Chunk[A], Any]): ZStream[R, E, A] =
new ZStream(channel)
/**
* Creates a stream from a [[zio.Chunk]] of values
*
* @param c
* a chunk of values
* @return
* a finite stream of values
*/
def fromChunk[O](chunk: => Chunk[O])(implicit trace: Trace): ZStream[Any, Nothing, O] =
new ZStream(
ZChannel.succeed(chunk).flatMap { chunk =>
if (chunk.isEmpty) ZChannel.unit else ZChannel.write(chunk)
}
)
/**
* Creates a stream from a subscription to a hub.
*/
def fromChunkHub[O](hub: => Hub[Chunk[O]])(implicit
trace: Trace
): ZStream[Any, Nothing, O] =
scoped(hub.subscribe).flatMap(queue => fromChunkQueue(queue))
/**
* Creates a stream from a subscription to a hub in the context of a scoped
* effect. The scoped effect describes subscribing to receive messages from
* the hub while the stream describes taking messages from the hub.
*/
def fromChunkHubScoped[O](
hub: => Hub[Chunk[O]]
)(implicit trace: Trace): ZIO[Scope, Nothing, ZStream[Any, Nothing, O]] =
hub.subscribe.map(queue => fromChunkQueue(queue))
/**
* Creates a stream from a subscription to a hub.
*
* The hub will be shut down once the stream is closed.
*/
def fromChunkHubWithShutdown[O](hub: => Hub[Chunk[O]])(implicit
trace: Trace
): ZStream[Any, Nothing, O] =
fromChunkHub(hub).ensuring(hub.shutdown)
/**
* Creates a stream from a subscription to a hub in the context of a scoped
* effect. The scoped effect describes subscribing to receive messages from
* the hub while the stream describes taking messages from the hub.
*
* The hub will be shut down once the stream is closed.
*/
def fromChunkHubScopedWithShutdown[O](
hub: => Hub[Chunk[O]]
)(implicit trace: Trace): ZIO[Scope, Nothing, ZStream[Any, Nothing, O]] =
fromChunkHubScoped(hub).map(_.ensuring(hub.shutdown))
/**
* Creates a stream from a queue of values
*/
def fromChunkQueue[O](
queue: => Dequeue[Chunk[O]]
)(implicit trace: Trace): ZStream[Any, Nothing, O] =
repeatZIOChunkOption {
queue.take
.catchAllCause(c =>
queue.isShutdown.flatMap { down =>
if (down && c.isInterrupted) Pull.end
else Pull.failCause(c)
}
)
}
/**
* Creates a stream from a queue of values. The queue will be shutdown once
* the stream is closed.
*/
def fromChunkQueueWithShutdown[O](queue: => Dequeue[Chunk[O]])(implicit
trace: Trace
): ZStream[Any, Nothing, O] =
fromChunkQueue(queue).ensuring(queue.shutdown)
/**
* Creates a stream from an arbitrary number of chunks.
*/
def fromChunks[O](cs: Chunk[O]*)(implicit trace: Trace): ZStream[Any, Nothing, O] =
fromIterable(cs).flatMap(fromChunk(_))
/**
* Creates a stream from a subscription to a hub.
*/
def fromHub[A](
hub: => Hub[A],
maxChunkSize: => Int = DefaultChunkSize
)(implicit trace: Trace): ZStream[Any, Nothing, A] =
scoped(hub.subscribe).flatMap(queue => fromQueue(queue, maxChunkSize))
/**
* Creates a stream from a subscription to a hub in the context of a scoped
* effect. The scoped effect describes subscribing to receive messages from
* the hub while the stream describes taking messages from the hub.
*/
def fromHubScoped[A](
hub: => Hub[A],
maxChunkSize: => Int = DefaultChunkSize
)(implicit trace: Trace): ZIO[Scope, Nothing, ZStream[Any, Nothing, A]] =
ZIO.suspendSucceed(hub.subscribe.map(queue => fromQueueWithShutdown(queue, maxChunkSize)))
/**
* Creates a stream from a subscription to a hub.
*
* The hub will be shut down once the stream is closed.
*/
def fromHubWithShutdown[A](
hub: => Hub[A],
maxChunkSize: => Int = DefaultChunkSize
)(implicit trace: Trace): ZStream[Any, Nothing, A] =
fromHub(hub, maxChunkSize).ensuring(hub.shutdown)
/**
* Creates a stream from a subscription to a hub in the context of a scoped
* effect. The scoped effect describes subscribing to receive messages from
* the hub while the stream describes taking messages from the hub.
*
* The hub will be shut down once the stream is closed.
*/
def fromHubScopedWithShutdown[A](
hub: => Hub[A],
maxChunkSize: => Int = DefaultChunkSize
)(implicit trace: Trace): ZIO[Scope, Nothing, ZStream[Any, Nothing, A]] =
fromHubScoped(hub, maxChunkSize).map(_.ensuring(hub.shutdown))
/**
* Creates a stream from a `java.io.InputStream`
*/
def fromInputStream(
is: => InputStream,
chunkSize: => Int = ZStream.DefaultChunkSize
)(implicit trace: Trace): ZStream[Any, IOException, Byte] =
ZStream.succeed((is, chunkSize)).flatMap { case (is, chunkSize) =>
ZStream.repeatZIOChunkOption {
for {
bufArray <- ZIO.succeed(Array.ofDim[Byte](chunkSize))
bytesRead <- ZIO.attemptBlockingIO(is.read(bufArray)).asSomeError
bytes <- if (bytesRead < 0)
ZIO.fail(None)
else if (bytesRead == 0)
ZIO.succeed(Chunk.empty)
else if (bytesRead < chunkSize)
ZIO.succeed(Chunk.fromArray(bufArray).take(bytesRead))
else
ZIO.succeed(Chunk.fromArray(bufArray))
} yield bytes
}
}
/**
* Creates a stream from a `java.io.InputStream`. Ensures that the input
* stream is closed after it is exhausted.
*/
def fromInputStreamZIO[R](
is: => ZIO[R, IOException, InputStream],
chunkSize: => Int = ZStream.DefaultChunkSize
)(implicit trace: Trace): ZStream[R, IOException, Byte] =
fromInputStreamScoped[R](ZIO.acquireRelease(is)(is => ZIO.succeed(is.close())), chunkSize)
/**
* Creates a stream from a scoped `java.io.InputStream` value.
*/
def fromInputStreamScoped[R](
is: => ZIO[Scope with R, IOException, InputStream],
chunkSize: => Int = ZStream.DefaultChunkSize
)(implicit trace: Trace): ZStream[R, IOException, Byte] =
ZStream.scoped[R](is).flatMap(fromInputStream(_, chunkSize))
/**
* Creates a stream from an iterable collection of values
*/
def fromIterable[O](as: => Iterable[O])(implicit trace: Trace): ZStream[Any, Nothing, O] =
fromIterable(as, DefaultChunkSize)
/**
* Creates a stream from an iterable collection of values
*/
def fromIterable[O](as: => Iterable[O], chunkSize: => Int)(implicit trace: Trace): ZStream[Any, Nothing, O] =
ZStream.suspend {
as match {
case chunk: Chunk[O] => ZStream.fromChunk(chunk)
case iterable: Iterable[O] => ZStream.fromIteratorSucceed(iterable.iterator, chunkSize)
}
}
/**
* Creates a stream from an effect producing a value of type `Iterable[A]`
*/
def fromIterableZIO[R, E, O](iterable: => ZIO[R, E, Iterable[O]])(implicit trace: Trace): ZStream[R, E, O] =
fromIterableZIO(iterable, DefaultChunkSize)
/**
* Creates a stream from an effect producing a value of type `Iterable[A]`
*/
def fromIterableZIO[R, E, O](iterable: => ZIO[R, E, Iterable[O]], chunkSize: => Int)(implicit
trace: Trace
): ZStream[R, E, O] =
ZStream.unwrap(iterable.map(fromIterable(_, chunkSize)))
/** Creates a stream from an iterator */
def fromIterator[A](iterator: => Iterator[A], maxChunkSize: => Int = DefaultChunkSize)(implicit
trace: Trace
): ZStream[Any, Throwable, A] =
ZStream.succeed(maxChunkSize).flatMap { maxChunkSize =>
if (maxChunkSize == 1) fromIteratorSingle(iterator)
else {
object StreamEnd extends Throwable
ZStream
.fromZIO(
FiberRef.currentFatal.get <*> ZIO.attempt(iterator) <*> ZIO.runtime[Any] <*> ZIO
.succeed(ChunkBuilder.make[A](maxChunkSize))
)
.flatMap { case (isFatal, it, rt, builder) =>
ZStream.repeatZIOChunkOption {
ZIO.attempt {
builder.clear()
var count = 0
try {
while (count < maxChunkSize && it.hasNext) {
builder += it.next()
count += 1
}
} catch {
case e: Throwable if !isFatal(e) =>
throw e
}
if (count > 0) {
builder.result()
} else {
throw StreamEnd
}
}.mapError {
case StreamEnd => None
case e => Some(e)
}
}
}
}
}
private def fromIteratorSingle[A](iterator: => Iterator[A])(implicit
trace: Trace
): ZStream[Any, Throwable, A] = {
object StreamEnd extends Throwable
ZStream.fromZIO(FiberRef.currentFatal.get <*> ZIO.attempt(iterator) <*> ZIO.runtime[Any]).flatMap {
case (isFatal, it, rt) =>
ZStream.repeatZIOOption {
ZIO.attempt {
val hasNext: Boolean =
try it.hasNext
catch {
case e: Throwable if !isFatal(e) =>
throw e
}
if (hasNext) {
try it.next()
catch {
case e: Throwable if !isFatal(e) =>
throw e
}
} else throw StreamEnd
}.mapError {
case StreamEnd => None
case e => Some(e)
}
}
}
}
/**
* Creates a stream from a scoped iterator
*/
def fromIteratorScoped[R, A](
iterator: => ZIO[Scope with R, Throwable, Iterator[A]],
maxChunkSize: => Int = DefaultChunkSize
)(implicit
trace: Trace
): ZStream[R, Throwable, A] =
scoped[R](iterator).flatMap(fromIterator(_, maxChunkSize))
/**
* Creates a stream from an iterator
*/
def fromIteratorSucceed[A](iterator: => Iterator[A], maxChunkSize: => Int = DefaultChunkSize)(implicit
trace: Trace
): ZStream[Any, Nothing, A] = {
def writeOneByOne(iterator: Iterator[A]): ZChannel[Any, Any, Any, Any, Nothing, Chunk[A], Any] =
if (iterator.hasNext)
ZChannel.write(Chunk.single(iterator.next())) *> writeOneByOne(iterator)
else
ZChannel.unit
def writeChunks(iterator: Iterator[A]): ZChannel[Any, Any, Any, Any, Nothing, Chunk[A], Any] =
ZChannel.succeed(ChunkBuilder.make[A]()).flatMap { builder =>
def loop(iterator: Iterator[A]): ZChannel[Any, Any, Any, Any, Nothing, Chunk[A], Any] = {
builder.clear()
var count = 0
while (count < maxChunkSize && iterator.hasNext) {
builder += iterator.next()
count += 1
}
if (count > 0)
ZChannel.write(builder.result()) *> loop(iterator)
else
ZChannel.unit
}
loop(iterator)
}
ZStream.fromChannel {
ZChannel.suspend {
if (maxChunkSize == 1)
writeOneByOne(iterator)
else
writeChunks(iterator)
}
}
}
/**
* Creates a stream from an iterator that may potentially throw exceptions
*/
def fromIteratorZIO[R, A](iterator: => ZIO[R, Throwable, Iterator[A]])(implicit
trace: Trace
): ZStream[R, Throwable, A] =
fromIteratorZIO(iterator, DefaultChunkSize)
/**
* Creates a stream from an iterator that may potentially throw exceptions
*/
def fromIteratorZIO[R, A](
iterator: => ZIO[R, Throwable, Iterator[A]],
chunkSize: Int
)(implicit trace: Trace): ZStream[R, Throwable, A] =
fromZIO(iterator).flatMap(fromIterator(_, chunkSize))
/**
* Creates a stream from a Java iterator that may throw exceptions
*/
def fromJavaIterator[A](iterator: => java.util.Iterator[A])(implicit trace: Trace): ZStream[Any, Throwable, A] =
fromJavaIterator(iterator, DefaultChunkSize)
/**
* Creates a stream from a Java iterator that may throw exceptions
*/
def fromJavaIterator[A](
iterator: => java.util.Iterator[A],
chunkSize: Int
)(implicit trace: Trace): ZStream[Any, Throwable, A] =
fromIterator(
{
val it = iterator // Scala 2.13 scala.collection.Iterator has `iterator` in local scope
new Iterator[A] {
def next(): A = it.next
def hasNext: Boolean = it.hasNext
}
},
chunkSize
)
/**
* Creates a stream from a scoped iterator
*/
def fromJavaIteratorScoped[R, A](iterator: => ZIO[Scope with R, Throwable, java.util.Iterator[A]])(implicit
trace: Trace
): ZStream[R, Throwable, A] =
fromJavaIteratorScoped[R, A](iterator, DefaultChunkSize)
/**
* Creates a stream from a scoped iterator
*/
def fromJavaIteratorScoped[R, A](
iterator: => ZIO[Scope with R, Throwable, java.util.Iterator[A]],
chunkSize: Int
)(implicit
trace: Trace
): ZStream[R, Throwable, A] =
scoped[R](iterator).flatMap(fromJavaIterator(_, chunkSize))
/**
* Creates a stream from a Java iterator
*/
def fromJavaIteratorSucceed[A](iterator: => java.util.Iterator[A])(implicit trace: Trace): ZStream[Any, Nothing, A] =
fromJavaIteratorSucceed(iterator, DefaultChunkSize)
/**
* Creates a stream from a Java iterator
*/
def fromJavaIteratorSucceed[A](
iterator: => java.util.Iterator[A],
chunkSize: Int
)(implicit trace: Trace): ZStream[Any, Nothing, A] =
fromIteratorSucceed(
{
val it = iterator // Scala 2.13 scala.collection.Iterator has `iterator` in local scope
new Iterator[A] {
def next(): A = it.next
def hasNext: Boolean = it.hasNext
}
},
chunkSize
)
/**
* Creates a stream from a Java iterator that may potentially throw exceptions
*/
def fromJavaIteratorZIO[R, A](iterator: => ZIO[R, Throwable, java.util.Iterator[A]])(implicit
trace: Trace
): ZStream[R, Throwable, A] =
fromJavaIteratorZIO(iterator, DefaultChunkSize)
/**
* Creates a stream from a Java iterator that may potentially throw exceptions
*/
def fromJavaIteratorZIO[R, A](
iterator: => ZIO[R, Throwable, java.util.Iterator[A]],
chunkSize: Int
)(implicit trace: Trace): ZStream[R, Throwable, A] =
fromZIO(iterator).flatMap(fromJavaIterator(_, chunkSize))
/**
* Creates a stream from a ZIO effect that pulls elements from another stream.
* See `toPull` for reference
*/
def fromPull[R, E, A](zio: ZIO[Scope with R, Nothing, ZIO[R, Option[E], Chunk[A]]])(implicit
trace: Trace
): ZStream[R, E, A] =
ZStream.unwrapScoped[R](zio.map(pull => repeatZIOChunkOption(pull)))
/**
* Creates a stream from a queue of values
*
* @param maxChunkSize
* Maximum number of queued elements to put in one chunk in the stream
*/
def fromQueue[O](
queue: => Dequeue[O],
maxChunkSize: => Int = DefaultChunkSize
)(implicit trace: Trace): ZStream[Any, Nothing, O] =
repeatZIOChunkOption {
queue
.takeBetween(1, maxChunkSize)
.catchAllCause(c =>
queue.isShutdown.flatMap { down =>
if (down && c.isInterrupted) Pull.end
else Pull.failCause(c)
}
)
}
/**
* Creates a stream from a queue of values. The queue will be shutdown once
* the stream is closed.
*
* @param maxChunkSize
* Maximum number of queued elements to put in one chunk in the stream
*/
def fromQueueWithShutdown[O](
queue: => Dequeue[O],
maxChunkSize: => Int = DefaultChunkSize
)(implicit trace: Trace): ZStream[Any, Nothing, O] =
fromQueue(queue, maxChunkSize).ensuring(queue.shutdown)
/**
* Creates a stream from a [[zio.Schedule]] that does not require any further
* input. The stream will emit an element for each value output from the
* schedule, continuing for as long as the schedule continues.
*/
def fromSchedule[R, A](schedule: => Schedule[R, Any, A])(implicit
trace: Trace
): ZStream[R, Nothing, A] =
unwrap(schedule.driver.map(driver => repeatZIOOption(driver.next(()))))
/**
* Creates a stream from a [[zio.stm.TPriorityQueue]] of values.
*/
def fromTPriorityQueue[A](queue: => TPriorityQueue[A])(implicit trace: Trace): ZStream[Any, Nothing, A] =
repeatZIOChunk(queue.take.map(Chunk.single(_)).commit)
/**
* Creates a stream from a [[zio.stm.TQueue]] of values.
*/
def fromTQueue[A](queue: => TDequeue[A])(implicit trace: Trace): ZStream[Any, Nothing, A] =
repeatZIOChunk(queue.take.map(Chunk.single(_)).commit)
/**
* Creates a stream from an effect producing a value of type `A`
*/
def fromZIO[R, E, A](fa: => ZIO[R, E, A])(implicit trace: Trace): ZStream[R, E, A] =
fromZIOOption(fa.mapError(Some(_)))
/**
* Creates a stream from an effect producing a value of type `A` or an empty
* Stream
*/
def fromZIOOption[R, E, A](fa: => ZIO[R, Option[E], A])(implicit trace: Trace): ZStream[R, E, A] =
new ZStream(
ZChannel.unwrap(
fa.fold(
{
case Some(e) => ZChannel.fail(e)
case None => ZChannel.unit
},
a => ZChannel.write(Chunk.single(a))
)
)
)
/**
* The infinite stream of iterative function application: a, f(a), f(f(a)),
* f(f(f(a))), ...
*/
def iterate[A](a: => A)(f: A => A)(implicit trace: Trace): ZStream[Any, Nothing, A] =
unfold(a)(a => Some((a, f(a))))
/**
* Logs the specified message at the current log level.
*/
def log(message: => String)(implicit trace: Trace): ZStream[Any, Nothing, Unit] =
ZStream.fromZIO(ZIO.log(message))
/**
* Annotates each log in streams composed after this with the specified log
* annotation.
*/
def logAnnotate(key: => String, value: => String)(implicit
trace: Trace
): ZStream[Any, Nothing, Unit] =
logAnnotate(LogAnnotation(key, value))
/**
* Annotates each log in streams composed after this with the specified log
* annotation.
*/
def logAnnotate(annotation: => LogAnnotation, annotations: LogAnnotation*)(implicit
trace: Trace
): ZStream[Any, Nothing, Unit] =
logAnnotate(Set(annotation) ++ annotations.toSet)
/**
* Annotates each log in streams composed after this with the specified log
* annotation.
*/
def logAnnotate(annotations: => Set[LogAnnotation])(implicit
trace: Trace
): ZStream[Any, Nothing, Unit] =
ZStream.scoped(ZIO.logAnnotateScoped(annotations))
/**
* Retrieves the log annotations associated with the current scope.
*/
def logAnnotations(implicit trace: Trace): ZStream[Any, Nothing, Map[String, String]] =
ZStream.fromZIO(FiberRef.currentLogAnnotations.get)
/**
* Logs the specified message at the debug log level.
*/
def logDebug(message: => String)(implicit trace: Trace): ZStream[Any, Nothing, Unit] =
ZStream.fromZIO(ZIO.logDebug(message))
/**
* Logs the specified message at the error log level.
*/
def logError(message: => String)(implicit trace: Trace): ZStream[Any, Nothing, Unit] =
ZStream.fromZIO(ZIO.logError(message))
/**
* Logs the specified cause as an error.
*/
def logErrorCause(cause: => Cause[Any])(implicit trace: Trace): ZStream[Any, Nothing, Unit] =
ZStream.fromZIO(ZIO.logErrorCause(cause))
/**
* Logs the specified message at the fatal log level.
*/
def logFatal(message: => String)(implicit trace: Trace): ZStream[Any, Nothing, Unit] =
ZStream.fromZIO(ZIO.logFatal(message))
/**
* Logs the specified message at the informational log level.
*/
def logInfo(message: => String)(implicit trace: Trace): ZStream[Any, Nothing, Unit] =
ZStream.fromZIO(ZIO.logInfo(message))
/**
* Sets the log level for streams composed after this.
*/
def logLevel(level: LogLevel)(implicit trace: Trace): ZStream[Any, Nothing, Unit] =
ZStream.scoped(ZIO.logLevelScoped(level))
/**
* Adjusts the label for the logging span for streams composed after this.
*/
def logSpan(label: => String)(implicit trace: Trace): ZStream[Any, Nothing, Unit] =
ZStream.scoped(ZIO.logSpanScoped(label))
/**
* Logs the specified message at the trace log level.
*/
def logTrace(message: => String)(implicit trace: Trace): ZStream[Any, Nothing, Unit] =
ZStream.fromZIO(ZIO.logTrace(message))
/**
* Logs the specified message at the warning log level.
*/
def logWarning(message: => String)(implicit trace: Trace): ZStream[Any, Nothing, Unit] =
ZStream.fromZIO(ZIO.logWarning(message))
/**
* Creates a single-valued stream from a scoped resource
*/
def scoped[R]: ScopedPartiallyApplied[R] =
new ScopedPartiallyApplied[R]
/**
* Creates a single-valued stream from a scoped resource
*/
def scopedWith[R, E, A](f: Scope => ZIO[R, E, A])(implicit trace: Trace): ZStream[R, E, A] =
new ZStream(ZChannel.scopedWith(scope => f(scope).map(Chunk.single)))
/**
* Merges a variable list of streams in a non-deterministic fashion. Up to `n`
* streams may be consumed in parallel and up to `outputBuffer` chunks may be
* buffered by this operator.
*/
def mergeAll[R, E, O](n: => Int, outputBuffer: => Int = 16)(
streams: ZStream[R, E, O]*
)(implicit trace: Trace): ZStream[R, E, O] =
fromIterable(streams).flattenPar(n, outputBuffer)
/**
* Like [[mergeAll]], but runs all streams concurrently.
*/
def mergeAllUnbounded[R, E, O](outputBuffer: => Int = 16)(
streams: ZStream[R, E, O]*
)(implicit trace: Trace): ZStream[R, E, O] = mergeAll(Int.MaxValue, outputBuffer)(streams: _*)
/**
* The stream that never produces any value or fails with any error.
*/
def never(implicit trace: Trace): ZStream[Any, Nothing, Nothing] =
ZStream.fromZIO(ZIO.never)
/**
* Like [[unfold]], but allows the emission of values to end one step further
* than the unfolding of the state. This is useful for embedding paginated
* APIs, hence the name.
*/
def paginate[R, E, A, S](s: => S)(f: S => (A, Option[S]))(implicit trace: Trace): ZStream[Any, Nothing, A] =
paginateChunk(s) { s =>
val page = f(s)
Chunk.single(page._1) -> page._2
}
/**
* Like [[unfoldChunk]], but allows the emission of values to end one step
* further than the unfolding of the state. This is useful for embedding
* paginated APIs, hence the name.
*/
def paginateChunk[A, S](
s: => S
)(f: S => (Chunk[A], Option[S]))(implicit trace: Trace): ZStream[Any, Nothing, A] = {
def loop(s: S): ZChannel[Any, Any, Any, Any, Nothing, Chunk[A], Any] =
f(s) match {
case (as, Some(s)) => ZChannel.write(as) *> loop(s)
case (as, None) => ZChannel.write(as) *> ZChannel.unit
}
new ZStream(loop(s))
}
/**
* Like [[unfoldChunkZIO]], but allows the emission of values to end one step
* further than the unfolding of the state. This is useful for embedding
* paginated APIs, hence the name.
*/
def paginateChunkZIO[R, E, A, S](
s: => S
)(f: S => ZIO[R, E, (Chunk[A], Option[S])])(implicit trace: Trace): ZStream[R, E, A] = {
def loop(s: S): ZChannel[R, Any, Any, Any, E, Chunk[A], Any] =
ZChannel.unwrap {
f(s).map {
case (as, Some(s)) => ZChannel.write(as) *> loop(s)
case (as, None) => ZChannel.write(as) *> ZChannel.unit
}
}
new ZStream(ZChannel.suspend(loop(s)))
}
def provideLayer[RIn, E, ROut, RIn2, ROut2](layer: ZLayer[RIn, E, ROut])(
stream: => ZStream[ROut with RIn2, E, ROut2]
)(implicit
ev: EnvironmentTag[RIn2],
tag: EnvironmentTag[ROut],
trace: Trace
): ZStream[RIn with RIn2, E, ROut2] =
ZStream.suspend(stream.provideSomeLayer[RIn with RIn2](ZLayer.environment[RIn2] ++ layer))
/**
* Like [[unfoldZIO]], but allows the emission of values to end one step
* further than the unfolding of the state. This is useful for embedding
* paginated APIs, hence the name.
*/
def paginateZIO[R, E, A, S](s: => S)(f: S => ZIO[R, E, (A, Option[S])])(implicit
trace: Trace
): ZStream[R, E, A] =
paginateChunkZIO(s)(f(_).map { case (a, s) => Chunk.single(a) -> s })
/**
* Constructs a stream from a range of integers (lower bound included, upper
* bound not included)
*/
def range(min: => Int, max: => Int, chunkSize: => Int = DefaultChunkSize)(implicit
trace: Trace
): ZStream[Any, Nothing, Int] =
ZStream.suspend {
def go(min: Int, max: Int, chunkSize: Int): ZChannel[Any, Any, Any, Any, Nothing, Chunk[Int], Any] = {
val remaining = max - min
if (remaining > chunkSize)
ZChannel.write(Chunk.fromArray(Array.range(min, min + chunkSize))) *> go(min + chunkSize, max, chunkSize)
else {
ZChannel.write(Chunk.fromArray(Array.range(min, min + remaining)))
}
}
new ZStream(go(min, max, chunkSize))
}
/**
* Repeats the provided value infinitely.
*/
def repeat[A](a: => A)(implicit trace: Trace): ZStream[Any, Nothing, A] =
new ZStream(ZChannel.succeed(a).flatMap(a => ZChannel.write(Chunk.single(a)).repeated))
/**
* Repeats the value using the provided schedule.
*/
def repeatWithSchedule[R, A](a: => A, schedule: => Schedule[R, A, _])(implicit
trace: Trace
): ZStream[R, Nothing, A] =
repeatZIOWithSchedule(ZIO.succeed(a), schedule)
/**
* Creates a stream from an effect producing a value of type `A` which repeats
* forever.
*/
def repeatZIO[R, E, A](fa: => ZIO[R, E, A])(implicit trace: Trace): ZStream[R, E, A] =
repeatZIOOption(fa.mapError(Some(_)))
/**
* Creates a stream from an effect producing chunks of `A` values which
* repeats forever.
*/
def repeatZIOChunk[R, E, A](fa: => ZIO[R, E, Chunk[A]])(implicit trace: Trace): ZStream[R, E, A] =
repeatZIOChunkOption(fa.mapError(Some(_)))
/**
* Creates a stream from an effect producing chunks of `A` values until it
* fails with None.
*/
def repeatZIOChunkOption[R, E, A](
fa: => ZIO[R, Option[E], Chunk[A]]
)(implicit trace: Trace): ZStream[R, E, A] =
unfoldChunkZIO(fa)(fa =>
fa.map(chunk => Some((chunk, fa))).catchAll {
case None => Exit.none
case Some(e) => Exit.fail(e)
}
)
/**
* Creates a stream from an effect producing values of type `A` until it fails
* with None.
*/
def repeatZIOOption[R, E, A](fa: => ZIO[R, Option[E], A])(implicit trace: Trace): ZStream[R, E, A] =
repeatZIOChunkOption(fa.map(Chunk.single))
/**
* Creates a stream from an effect producing a value of type `A`, which is
* repeated using the specified schedule.
*/
def repeatZIOWithSchedule[R, E, A](
effect: => ZIO[R, E, A],
schedule: => Schedule[R, A, Any]
)(implicit trace: Trace): ZStream[R, E, A] =
ZStream((effect, schedule)).flatMap { case (effect, schedule) =>
ZStream.fromZIO(effect zip schedule.driver).flatMap { case (a, driver) =>
ZStream.succeed(a) ++
ZStream.unfoldZIO(a)(driver.next(_).foldZIO(ZIO.succeed(_), _ => effect.map(nextA => Some(nextA -> nextA))))
}
}
/**
* Accesses the specified service in the environment of the effect.
*/
def service[A: Tag](implicit trace: Trace): ZStream[A, Nothing, A] =
ZStream.serviceWith(identity)
/**
* Accesses the service corresponding to the specified key in the environment.
*/
def serviceAt[Service]: ZStream.ServiceAtPartiallyApplied[Service] =
new ZStream.ServiceAtPartiallyApplied[Service]
/**
* Accesses the specified service in the environment of the stream.
*/
def serviceWith[Service]: ServiceWithPartiallyApplied[Service] =
new ServiceWithPartiallyApplied[Service]
/**
* Accesses the specified service in the environment of the stream in the
* context of an effect.
*/
def serviceWithZIO[Service]: ServiceWithZIOPartiallyApplied[Service] =
new ServiceWithZIOPartiallyApplied[Service]
/**
* Accesses the specified service in the environment of the stream in the
* context of a stream.
*/
def serviceWithStream[Service]: ServiceWithStreamPartiallyApplied[Service] =
new ServiceWithStreamPartiallyApplied[Service]
/**
* Creates a single-valued pure stream
*/
def succeed[A](a: => A)(implicit trace: Trace): ZStream[Any, Nothing, A] =
fromChunk(Chunk.single(a))
/**
* Returns a lazily constructed stream.
*/
def suspend[R, E, A](stream: => ZStream[R, E, A]): ZStream[R, E, A] =
new ZStream(ZChannel.suspend(stream.channel))
/**
* Annotates each metric in streams composed after this with the specified
* tag.
*/
def tagged(key: => String, value: => String)(implicit trace: Trace): ZStream[Any, Nothing, Unit] =
tagged(Set(MetricLabel(key, value)))
/**
* Annotates each metric in streams composed after this with the specified
* tag.
*/
def tagged(tag: => MetricLabel, tags: MetricLabel*)(implicit trace: Trace): ZStream[Any, Nothing, Unit] =
tagged(Set(tag) ++ tags.toSet)
/**
* Annotates each metric in streams composed after this with the specified
* tag.
*/
def tagged(tags: => Set[MetricLabel])(implicit trace: Trace): ZStream[Any, Nothing, Unit] =
ZStream.scoped(ZIO.taggedScoped(tags))
/**
* Retrieves the metric tags associated with the current scope.
*/
def tags(implicit trace: Trace): ZStream[Any, Nothing, Set[MetricLabel]] =
ZStream.fromZIO(ZIO.tags)
/**
* A stream that emits Unit values spaced by the specified duration.
*/
def tick(interval: => Duration)(implicit trace: Trace): ZStream[Any, Nothing, Unit] =
repeatWithSchedule((), Schedule.spaced(interval))
/**
* A stream that contains a single `Unit` value.
*/
val unit: ZStream[Any, Nothing, Unit] =
succeed(())(Trace.empty)
/**
* Creates a stream by peeling off the "layers" of a value of type `S`
*/
def unfold[S, A](s: => S)(f: S => Option[(A, S)])(implicit trace: Trace): ZStream[Any, Nothing, A] =
unfoldChunk(s)(f(_).map { case (a, s) => Chunk.single(a) -> s })
/**
* Creates a stream by peeling off the "layers" of a value of type `S`.
*/
def unfoldChunk[S, A](
s: => S
)(f: S => Option[(Chunk[A], S)])(implicit trace: Trace): ZStream[Any, Nothing, A] = {
def loop(s: S): ZChannel[Any, Any, Any, Any, Nothing, Chunk[A], Any] =
f(s) match {
case Some((as, s)) => ZChannel.write(as) *> loop(s)
case None => ZChannel.unit
}
new ZStream(ZChannel.suspend(loop(s)))
}
/**
* Creates a stream by effectfully peeling off the "layers" of a value of type
* `S`
*/
def unfoldChunkZIO[R, E, A, S](
s: => S
)(f: S => ZIO[R, E, Option[(Chunk[A], S)]])(implicit trace: Trace): ZStream[R, E, A] = {
def loop(s: S): ZChannel[R, Any, Any, Any, E, Chunk[A], Any] =
ZChannel.unwrap {
f(s).map {
case Some((as, s)) => ZChannel.write(as) *> loop(s)
case None => ZChannel.unit
}
}
new ZStream(loop(s))
}
/**
* Creates a stream by effectfully peeling off the "layers" of a value of type
* `S`
*/
def unfoldZIO[R, E, A, S](s: => S)(f: S => ZIO[R, E, Option[(A, S)]])(implicit
trace: Trace
): ZStream[R, E, A] =
unfoldChunkZIO(s)(f(_).map(_.map { case (a, s) => Chunk.single(a) -> s }))
/**
* Creates a stream produced from an effect
*/
def unwrap[R, E, A](fa: => ZIO[R, E, ZStream[R, E, A]])(implicit trace: Trace): ZStream[R, E, A] =
fromZIO(fa).flatten
/**
* Creates a stream produced from a scoped [[ZIO]]
*/
def unwrapScoped[R]: UnwrapScopedPartiallyApplied[R] =
new UnwrapScopedPartiallyApplied[R]
/**
* Creates a stream produced from a scoped [[ZIO]]
*/
def unwrapScopedWith[R, E, A](f: Scope => ZIO[R, E, ZStream[R, E, A]])(implicit trace: Trace): ZStream[R, E, A] =
scopedWith(scope => f(scope)).flatten
/**
* Returns the specified stream if the given condition is satisfied, otherwise
* returns an empty stream.
*/
def when[R, E, O](b: => Boolean)(zStream: => ZStream[R, E, O])(implicit trace: Trace): ZStream[R, E, O] =
whenZIO(ZIO.succeed(b))(zStream)
/**
* Returns the resulting stream when the given `PartialFunction` is defined
* for the given value, otherwise returns an empty stream.
*/
def whenCase[R, E, A, O](a: => A)(pf: PartialFunction[A, ZStream[R, E, O]])(implicit
trace: Trace
): ZStream[R, E, O] =
whenCaseZIO(ZIO.succeed(a))(pf)
/**
* Returns the resulting stream when the given `PartialFunction` is defined
* for the given effectful value, otherwise returns an empty stream.
*/
def whenCaseZIO[R, E, A](a: => ZIO[R, E, A]): WhenCaseZIO[R, E, A] =
new WhenCaseZIO(() => a)
/**
* Returns the specified stream if the given effectful condition is satisfied,
* otherwise returns an empty stream.
*/
def whenZIO[R, E](b: => ZIO[R, E, Boolean]) =
new WhenZIO(() => b)
final class EnvironmentWithPartiallyApplied[R](private val dummy: Boolean = true) extends AnyVal {
def apply[A](f: ZEnvironment[R] => A)(implicit trace: Trace): ZStream[R, Nothing, A] =
ZStream.environment[R].map(f)
}
final class EnvironmentWithZIOPartiallyApplied[R](private val dummy: Boolean = true) extends AnyVal {
def apply[R1 <: R, E, A](f: ZEnvironment[R] => ZIO[R1, E, A])(implicit
trace: Trace
): ZStream[R with R1, E, A] =
ZStream.environment[R].mapZIO(f)
}
final class EnvironmentWithStreamPartiallyApplied[R](private val dummy: Boolean = true) extends AnyVal {
def apply[R1 <: R, E, A](f: ZEnvironment[R] => ZStream[R1, E, A])(implicit
trace: Trace
): ZStream[R with R1, E, A] =
ZStream.environment[R].flatMap(f)
}
final class ScopedPartiallyApplied[R](private val dummy: Boolean = true) extends AnyVal {
def apply[E, A](zio: => ZIO[Scope with R, E, A])(implicit trace: Trace): ZStream[R, E, A] =
new ZStream(ZChannel.scoped[R](zio.map(Chunk.single)))
}
final class ServiceAtPartiallyApplied[Service](private val dummy: Boolean = true) extends AnyVal {
def apply[Key](
key: => Key
)(implicit
tag: EnvironmentTag[Map[Key, Service]],
trace: Trace
): ZStream[Map[Key, Service], Nothing, Option[Service]] =
ZStream.environmentWith(_.getAt(key))
}
final class ServiceWithPartiallyApplied[Service](private val dummy: Boolean = true) extends AnyVal {
def apply[A](f: Service => A)(implicit
tag: Tag[Service],
trace: Trace
): ZStream[Service, Nothing, A] =
ZStream.fromZIO(ZIO.serviceWith[Service](f))
}
final class ServiceWithZIOPartiallyApplied[Service](private val dummy: Boolean = true) extends AnyVal {
def apply[R <: Service, E, A](f: Service => ZIO[R, E, A])(implicit
tag: Tag[Service],
trace: Trace
): ZStream[R with Service, E, A] =
ZStream.fromZIO(ZIO.serviceWithZIO[Service](f))
}
final class ServiceWithStreamPartiallyApplied[Service](private val dummy: Boolean = true) extends AnyVal {
def apply[R <: Service, E, A](f: Service => ZStream[R, E, A])(implicit
tag: Tag[Service],
trace: Trace
): ZStream[R with Service, E, A] =
ZStream.service[Service].flatMap(f)
}
final class UnwrapScopedPartiallyApplied[R](private val dummy: Boolean = true) extends AnyVal {
def apply[E, A](fa: => ZIO[Scope with R, E, ZStream[R, E, A]])(implicit
trace: Trace
): ZStream[R, E, A] =
scoped[R](fa).flatten
}
/**
* Representation of a grouped stream. This allows to filter which groups will
* be processed. Once this is applied all groups will be processed in parallel
* and the results will be merged in arbitrary order.
*/
sealed trait GroupBy[-R, +E, +K, +V] { self =>
protected def grouped(implicit trace: Trace): ZStream[R, E, (K, Dequeue[Take[E, V]])]
/**
* Run the function across all groups, collecting the results in an
* arbitrary order.
*/
def apply[R1 <: R, E1 >: E, A](f: (K, ZStream[Any, E, V]) => ZStream[R1, E1, A], buffer: => Int = 16)(implicit
trace: Trace
): ZStream[R1, E1, A] =
grouped.flatMapPar[R1, E1, A](Int.MaxValue, buffer) { case (k, q) =>
f(k, ZStream.fromQueueWithShutdown(q).flattenTake)
}
/**
* Only consider the first n groups found in the stream.
*/
def first(n: => Int): GroupBy[R, E, K, V] =
new GroupBy[R, E, K, V] {
override def grouped(implicit trace: Trace): ZStream[R, E, (K, Dequeue[Take[E, V]])] =
self.grouped.zipWithIndex.filterZIO { case elem @ ((_, q), i) =>
if (i < n) ZIO.succeed(elem).as(true)
else q.shutdown.as(false)
}.map(_._1)
}
/**
* Filter the groups to be processed.
*/
def filter(f: K => Boolean): GroupBy[R, E, K, V] =
new GroupBy[R, E, K, V] {
override def grouped(implicit trace: Trace): ZStream[R, E, (K, Dequeue[Take[E, V]])] =
self.grouped.filterZIO { case elem @ (k, q) =>
if (f(k)) ZIO.succeed(elem).as(true)
else q.shutdown.as(false)
}
}
}
final class ProvideSomeLayer[R0, -R, +E, +A](private val self: ZStream[R, E, A]) extends AnyVal {
def apply[E1 >: E, R1](
layer: => ZLayer[R0, E1, R1]
)(implicit
ev: R0 with R1 <:< R,
tagged: EnvironmentTag[R1],
trace: Trace
): ZStream[R0, E1, A] =
self.asInstanceOf[ZStream[R0 with R1, E, A]].provideLayer(ZLayer.environment[R0] ++ layer)
}
final class UpdateService[-R, +E, +A, M](private val self: ZStream[R, E, A]) extends AnyVal {
def apply[R1 <: R with M](
f: M => M
)(implicit tag: Tag[M], trace: Trace): ZStream[R1, E, A] =
self.provideSomeEnvironment(_.update(f))
}
final class UpdateServiceAt[-R, +E, +A, Service](private val self: ZStream[R, E, A]) extends AnyVal {
def apply[R1 <: R with Map[Key, Service], Key](key: => Key)(
f: Service => Service
)(implicit tag: Tag[Map[Key, Service]], trace: Trace): ZStream[R1, E, A] =
self.provideSomeEnvironment(_.updateAt(key)(f))
}
/**
* A `ZStreamConstructor[Input]` knows how to construct a `ZStream` value from
* an input of type `Input`. This allows the type of the `ZStream` value
* constructed to depend on `Input`.
*/
trait ZStreamConstructor[Input] {
/**
* The type of the `ZStream` value.
*/
type Out
/**
* Constructs a `ZStream` value from the specified input.
*/
def make(input: => Input)(implicit trace: Trace): Out
}
object ZStreamConstructor extends ZStreamConstructorPlatformSpecific {
/**
* Constructs a `ZStream[R, E, A]` from a [[zio.stream.ZChannel]]
*/
implicit def ChannelConstructor[R, E, A]: WithOut[ZChannel[R, Any, Any, Any, E, Chunk[A], Any], ZStream[R, E, A]] =
new ZStreamConstructor[ZChannel[R, Any, Any, Any, E, Chunk[A], Any]] {
type Out = ZStream[R, E, A]
def make(input: => ZChannel[R, Any, Any, Any, E, Chunk[A], Any])(implicit trace: Trace): ZStream[R, E, A] =
ZStream.fromChannel(input)
}
/**
* Constructs a `ZStream[Any, Nothing, A]` from a `Hub[Chunk[A]]`.
*/
implicit def ChunkHubConstructor[A]: WithOut[Hub[Chunk[A]], ZStream[Any, Nothing, A]] =
new ZStreamConstructor[Hub[Chunk[A]]] {
type Out = ZStream[Any, Nothing, A]
def make(input: => Hub[Chunk[A]])(implicit trace: Trace): ZStream[Any, Nothing, A] =
ZStream.fromChunkHub(input)
}
/**
* Constructs a `ZStream[Any, Nothing, A]` from a Queue[Chunk[A]]`.
*/
implicit def ChunkQueueConstructor[A]: WithOut[Queue[Chunk[A]], ZStream[Any, Nothing, A]] =
new ZStreamConstructor[Queue[Chunk[A]]] {
type Out = ZStream[Any, Nothing, A]
def make(input: => Queue[Chunk[A]])(implicit trace: Trace): ZStream[Any, Nothing, A] =
ZStream.fromChunkQueue(input)
}
/**
* Constructs a `ZStream[Any, Nothing, A]` from an `Iterable[Chunk[A]]`.
*/
implicit def ChunksConstructor[A, Collection[Element] <: Iterable[Element]]
: WithOut[Collection[Chunk[A]], ZStream[Any, Nothing, A]] =
new ZStreamConstructor[Collection[Chunk[A]]] {
type Out = ZStream[Any, Nothing, A]
def make(input: => Collection[Chunk[A]])(implicit trace: Trace): ZStream[Any, Nothing, A] =
ZStream.fromIterable(input).flatMap(ZStream.fromChunk(_))
}
/**
* Constructs a `ZStream[R, E, A]` from a `ZIO[R, E, Iterable[A]]`.
*/
implicit def IterableZIOConstructor[R, E, A, Collection[Element] <: Iterable[Element]]
: WithOut[ZIO[R, E, Collection[A]], ZStream[R, E, A]] =
new ZStreamConstructor[ZIO[R, E, Collection[A]]] {
type Out = ZStream[R, E, A]
def make(input: => ZIO[R, E, Collection[A]])(implicit trace: Trace): ZStream[R, E, A] =
ZStream.fromIterableZIO(input)
}
/**
* Constructs a `ZStream[Any, Throwable, A]` from an `Iterator[A]`.
*/
implicit def IteratorConstructor[A, IteratorLike[Element] <: Iterator[Element]]
: WithOut[IteratorLike[A], ZStream[Any, Throwable, A]] =
new ZStreamConstructor[IteratorLike[A]] {
type Out = ZStream[Any, Throwable, A]
def make(input: => IteratorLike[A])(implicit trace: Trace): ZStream[Any, Throwable, A] =
ZStream.fromIterator(input)
}
/**
* Constructs a `ZStream[R, Throwable, A]` from a `ZIO[R with Scope,
* Throwable, Iterator[A]]`.
*/
implicit def IteratorScopedConstructor[R, E <: Throwable, A, IteratorLike[Element] <: Iterator[Element]]
: WithOut[ZIO[Scope with R, E, IteratorLike[A]], ZStream[R, Throwable, A]] =
new ZStreamConstructor[ZIO[Scope with R, E, IteratorLike[A]]] {
type Out = ZStream[R, Throwable, A]
def make(input: => ZIO[Scope with R, E, IteratorLike[A]])(implicit
trace: Trace
): ZStream[R, Throwable, A] =
ZStream.fromIteratorScoped[R, A](input)
}
/**
* Constructs a `ZStream[R, Throwable, A]` from a `ZIO[R, Throwable,
* Iterator[A]]`.
*/
implicit def IteratorZIOConstructor[R, E <: Throwable, A, IteratorLike[Element] <: Iterator[Element]]
: WithOut[ZIO[R, E, IteratorLike[A]], ZStream[R, Throwable, A]] =
new ZStreamConstructor[ZIO[R, E, IteratorLike[A]]] {
type Out = ZStream[R, Throwable, A]
def make(input: => ZIO[R, E, IteratorLike[A]])(implicit trace: Trace): ZStream[R, Throwable, A] =
ZStream.fromIteratorZIO(input)
}
/**
* Constructs a `ZStream[Any, Throwable, A]` from a `java.util.Iterator[A]`.
*/
implicit def JavaIteratorConstructor[A, JaveIteratorLike[Element] <: java.util.Iterator[Element]]
: WithOut[JaveIteratorLike[A], ZStream[Any, Throwable, A]] =
new ZStreamConstructor[JaveIteratorLike[A]] {
type Out = ZStream[Any, Throwable, A]
def make(input: => JaveIteratorLike[A])(implicit trace: Trace): ZStream[Any, Throwable, A] =
ZStream.fromJavaIterator(input)
}
/**
* Constructs a `ZStream[R, Throwable, A]` from a `ZIO[R with Scope,
* Throwable, java.util.Iterator[A]]`.
*/
implicit def JavaIteratorScopedConstructor[R, E <: Throwable, A, JaveIteratorLike[Element] <: java.util.Iterator[
Element
]]: WithOut[ZIO[Scope with R, E, JaveIteratorLike[A]], ZStream[R, Throwable, A]] =
new ZStreamConstructor[ZIO[Scope with R, E, JaveIteratorLike[A]]] {
type Out = ZStream[R, Throwable, A]
def make(input: => ZIO[Scope with R, E, JaveIteratorLike[A]])(implicit
trace: Trace
): ZStream[R, Throwable, A] =
ZStream.fromJavaIteratorScoped[R, A](input)
}
/**
* Constructs a `ZStream[R, Throwable, A]` from a `ZIO[R, Throwable,
* java.util.Iterator[A]]`.
*/
implicit def JavaIteratorZIOConstructor[R, E <: Throwable, A, JaveIteratorLike[Element] <: java.util.Iterator[
Element
]]: WithOut[ZIO[R, E, JaveIteratorLike[A]], ZStream[R, Throwable, A]] =
new ZStreamConstructor[ZIO[R, E, JaveIteratorLike[A]]] {
type Out = ZStream[R, Throwable, A]
def make(input: => ZIO[R, E, JaveIteratorLike[A]])(implicit trace: Trace): ZStream[R, Throwable, A] =
ZStream.fromJavaIteratorZIO(input)
}
/**
* Constructs a `ZStream[R, Nothing, A]` from a `Schedule[R, Any, A]`.
*/
implicit def ScheduleConstructor[R, A]: WithOut[Schedule[R, Any, A], ZStream[R, Nothing, A]] =
new ZStreamConstructor[Schedule[R, Any, A]] {
type Out = ZStream[R, Nothing, A]
def make(input: => Schedule[R, Any, A])(implicit trace: Trace): ZStream[R, Nothing, A] =
ZStream.fromSchedule(input)
}
/**
* Constructs a `ZStream[Any, Nothing, A]` from a `TQueue[A]`.
*/
implicit def TQueueConstructor[A]: WithOut[TQueue[A], ZStream[Any, Nothing, A]] =
new ZStreamConstructor[TQueue[A]] {
type Out = ZStream[Any, Nothing, A]
def make(input: => TQueue[A])(implicit trace: Trace): ZStream[Any, Nothing, A] =
ZStream.fromTQueue(input)
}
}
trait ZStreamConstructorLowPriority1 extends ZStreamConstructorLowPriority2 {
/**
* Constructs a `ZStream[Any, Nothing, A]` from a `Chunk[A]`.
*/
implicit def ChunkConstructor[A]: WithOut[Chunk[A], ZStream[Any, Nothing, A]] =
new ZStreamConstructor[Chunk[A]] {
type Out = ZStream[Any, Nothing, A]
def make(input: => Chunk[A])(implicit trace: Trace): ZStream[Any, Nothing, A] =
ZStream.fromChunk(input)
}
/**
* Constructs a `ZStream[Any, Nothing, A]` from a `Hub[A]`.
*/
implicit def HubConstructor[A]: WithOut[Hub[A], ZStream[Any, Nothing, A]] =
new ZStreamConstructor[Hub[A]] {
type Out = ZStream[Any, Nothing, A]
def make(input: => Hub[A])(implicit trace: Trace): ZStream[Any, Nothing, A] =
ZStream.fromHub(input)
}
/**
* Constructs a `ZStream[Any, Nothing, A]` from a `Iterable[A]`.
*/
implicit def IterableConstructor[A, Collection[Element] <: Iterable[Element]]
: WithOut[Collection[A], ZStream[Any, Nothing, A]] =
new ZStreamConstructor[Collection[A]] {
type Out = ZStream[Any, Nothing, A]
def make(input: => Collection[A])(implicit trace: Trace): ZStream[Any, Nothing, A] =
ZStream.fromIterable(input)
}
/**
* Constructs a `ZStream[Any, Nothing, A]` from a `Queue[A]`.
*/
implicit def QueueConstructor[A]: WithOut[Queue[A], ZStream[Any, Nothing, A]] =
new ZStreamConstructor[Queue[A]] {
type Out = ZStream[Any, Nothing, A]
def make(input: => Queue[A])(implicit trace: Trace): ZStream[Any, Nothing, A] =
ZStream.fromQueue(input)
}
/**
* Construct a `ZStream[R, E, A]` from a `ZIO[R, Option[E], A]`.
*/
implicit def ZIOOptionConstructor[R, E, A]: WithOut[ZIO[R, Option[E], A], ZStream[R, E, A]] =
new ZStreamConstructor[ZIO[R, Option[E], A]] {
type Out = ZStream[R, E, A]
def make(input: => ZIO[R, Option[E], A])(implicit trace: Trace): ZStream[R, E, A] =
ZStream.fromZIOOption(input)
}
/**
* Construct a `ZStream[R, E, A]` from a `ZIO[R, Option[E], A]`.
*/
implicit def ZIOOptionNoneConstructor[R, A]: WithOut[ZIO[R, None.type, A], ZStream[R, Nothing, A]] =
new ZStreamConstructor[ZIO[R, None.type, A]] {
type Out = ZStream[R, Nothing, A]
def make(input: => ZIO[R, None.type, A])(implicit trace: Trace): ZStream[R, Nothing, A] =
ZStream.fromZIOOption(input)
}
/**
* Construct a `ZStream[R, E, A]` from a `ZIO[R, Option[E], A]`.
*/
implicit def ZIOOptionSomeConstructor[R, E, A]: WithOut[ZIO[R, Some[E], A], ZStream[R, E, A]] =
new ZStreamConstructor[ZIO[R, Some[E], A]] {
type Out = ZStream[R, E, A]
def make(input: => ZIO[R, Some[E], A])(implicit trace: Trace): ZStream[R, E, A] =
ZStream.fromZIOOption(input)
}
}
trait ZStreamConstructorLowPriority2 extends ZStreamConstructorLowPriority3 {
/**
* Construct a `ZStream[R, E, A]` from a `ZIO[R, E, A]`.
*/
implicit def ZIOConstructor[R, E, A]: WithOut[ZIO[R, E, A], ZStream[R, E, A]] =
new ZStreamConstructor[ZIO[R, E, A]] {
type Out = ZStream[R, E, A]
def make(input: => ZIO[R, E, A])(implicit trace: Trace): ZStream[R, E, A] =
ZStream.fromZIO(input)
}
}
trait ZStreamConstructorLowPriority3 {
/**
* The type of the `ZStreamConstructor` with the type of the `ZStream`
* value.
*/
type WithOut[In, Out0] = ZStreamConstructor[In] { type Out = Out0 }
/**
* Construct a `ZStream[R, E, A]` from a `ZIO[R, E, A]`.
*/
implicit def SucceedConstructor[A]: WithOut[A, ZStream[Any, Nothing, A]] =
new ZStreamConstructor[A] {
type Out = ZStream[Any, Nothing, A]
def make(input: => A)(implicit trace: Trace): ZStream[Any, Nothing, A] =
ZStream.succeed(input)
}
}
type Pull[-R, +E, +A] = ZIO[R, Option[E], Chunk[A]]
private[zio] object Pull {
def emit[A](a: A)(implicit trace: Trace): IO[Nothing, Chunk[A]] = ZIO.succeed(Chunk.single(a))
def emit[A](as: Chunk[A])(implicit trace: Trace): IO[Nothing, Chunk[A]] = ZIO.succeed(as)
def fromDequeue[E, A](d: Dequeue[stream.Take[E, A]])(implicit trace: Trace): IO[Option[E], Chunk[A]] =
d.take.flatMap(_.done)
def fail[E](e: E)(implicit trace: Trace): IO[Option[E], Nothing] = ZIO.fail(Some(e))
def failCause[E](c: Cause[E])(implicit trace: Trace): IO[Option[E], Nothing] =
Exit.failCause(c).mapError(Some(_))
def empty[A](implicit trace: Trace): IO[Nothing, Chunk[A]] = ZIO.succeed(Chunk.empty)
def end(implicit trace: Trace): IO[Option[Nothing], Nothing] = Exit.failNone
}
private[zio] case class BufferedPull[R, E, A](
upstream: ZIO[R, Option[E], Chunk[A]],
done: Ref[Boolean],
cursor: Ref[(Chunk[A], Int)]
) {
def ifNotDone[R1, E1, A1](fa: ZIO[R1, Option[E1], A1])(implicit trace: Trace): ZIO[R1, Option[E1], A1] =
done.get.flatMap(
if (_) Pull.end
else fa
)
def update(implicit trace: Trace): ZIO[R, Option[E], Unit] =
ifNotDone {
upstream.foldZIO(
{
case None => done.set(true) *> Pull.end
case Some(e) => Pull.fail(e)
},
chunk => cursor.set(chunk -> 0)
)
}
def pullElement(implicit trace: Trace): ZIO[R, Option[E], A] =
ifNotDone {
cursor.modify { case (chunk, idx) =>
if (idx >= chunk.size) (update *> pullElement, (Chunk.empty, 0))
else (ZIO.succeed(chunk(idx)), (chunk, idx + 1))
}.flatten
}
def pullChunk(implicit trace: Trace): ZIO[R, Option[E], Chunk[A]] =
ifNotDone {
cursor.modify { case (chunk, idx) =>
if (idx >= chunk.size) (update *> pullChunk, (Chunk.empty, 0))
else (ZIO.succeed(chunk.drop(idx)), (Chunk.empty, 0))
}.flatten
}
}
private[zio] object BufferedPull {
def make[R, E, A](
pull: ZIO[R, Option[E], Chunk[A]]
)(implicit trace: Trace): ZIO[R, Nothing, BufferedPull[R, E, A]] =
for {
done <- Ref.make(false)
cursor <- Ref.make[(Chunk[A], Int)](Chunk.empty -> 0)
} yield BufferedPull(pull, done, cursor)
}
/**
* A synchronous queue-like abstraction that allows a producer to offer an
* element and wait for it to be taken, and allows a consumer to wait for an
* element to be available.
*/
private[zio] class Handoff[A](ref: Ref[Handoff.State[A]]) {
def offer(a: A)(implicit trace: Trace): UIO[Unit] =
Promise.make[Nothing, Unit].flatMap { p =>
ref.modify {
case s @ Handoff.State.Full(_, notifyProducer) => (notifyProducer.await *> offer(a), s)
case Handoff.State.Empty(notifyConsumer) => (notifyConsumer.succeed(()) *> p.await, Handoff.State.Full(a, p))
}.flatten
}
def take(implicit trace: Trace): UIO[A] =
Promise.make[Nothing, Unit].flatMap { p =>
ref.modify {
case Handoff.State.Full(a, notifyProducer) => (notifyProducer.succeed(()).as(a), Handoff.State.Empty(p))
case s @ Handoff.State.Empty(notifyConsumer) => (notifyConsumer.await *> take, s)
}.flatten
}
def poll(implicit trace: Trace): UIO[Option[A]] =
Promise.make[Nothing, Unit].flatMap { p =>
ref.modify {
case Handoff.State.Full(a, notifyProducer) => (notifyProducer.succeed(()).as(Some(a)), Handoff.State.Empty(p))
case s @ Handoff.State.Empty(_) => (ZIO.succeed(None), s)
}.flatten
}
}
private[zio] object Handoff {
def make[A](implicit trace: Trace): UIO[Handoff[A]] =
Promise
.make[Nothing, Unit]
.flatMap(p => Ref.make[State[A]](State.Empty(p)))
.map(new Handoff(_))
sealed trait State[+A]
object State {
case class Empty(notifyConsumer: Promise[Nothing, Unit]) extends State[Nothing]
case class Full[+A](a: A, notifyProducer: Promise[Nothing, Unit]) extends State[A]
}
}
final class WhenZIO[R, E](private val b: () => ZIO[R, E, Boolean]) extends AnyVal {
def apply[R1 <: R, E1 >: E, O](zStream: ZStream[R1, E1, O])(implicit trace: Trace): ZStream[R1, E1, O] =
fromZIO(b()).flatMap(if (_) zStream else ZStream.empty)
}
final class WhenCaseZIO[R, E, A](private val a: () => ZIO[R, E, A]) extends AnyVal {
def apply[R1 <: R, E1 >: E, O](pf: PartialFunction[A, ZStream[R1, E1, O]])(implicit
trace: Trace
): ZStream[R1, E1, O] =
fromZIO(a()).flatMap(pf.applyOrElse(_, (_: A) => ZStream.empty))
}
sealed trait HaltStrategy
object HaltStrategy {
case object Left extends HaltStrategy
case object Right extends HaltStrategy
case object Both extends HaltStrategy
case object Either extends HaltStrategy
}
implicit final class RefineToOrDieOps[R, E <: Throwable, A](private val self: ZStream[R, E, A]) extends AnyVal {
/**
* Keeps some of the errors, and terminates the fiber with the rest.
*/
def refineToOrDie[E1 <: E: ClassTag](implicit ev: CanFail[E], trace: Trace): ZStream[R, E1, A] =
self.refineOrDie { case e: E1 => e }
}
implicit final class SyntaxOps[-R, +E, O](self: ZStream[R, E, O]) {
/*
* Collect elements of the given type flowing through the stream, and filters out others.
*/
def collectType[O1 <: O](implicit tag: ClassTag[O1], trace: Trace): ZStream[R, E, O1] =
self.collect { case o if tag.runtimeClass.isInstance(o) => o.asInstanceOf[O1] }
}
private[zio] class Rechunker[A](n: Int) {
private var buffer: Chunk[A] = Chunk.empty[A]
private var chunkBuilder: ChunkBuilder[A] = null
private var pos: Int = 0
def isEmpty: Boolean = pos == 0
final def rechunk(
chunk: Chunk[A]
)(implicit trace: Trace): ZChannel[Any, ZNothing, Any, Any, ZNothing, Chunk[A], Any] = {
val chunkSize = chunk.size
if (chunkSize == 0) {
null
} else if (isEmpty && chunkSize == n) {
ZChannel.write(chunk)
} else if (n == 1) {
rechunk1(chunk, chunkSize)
} else if (chunkSize < 25) {
// Optimized for small chunks. The limit 25 comes from testing with benchmarks
var i = 0
var channel: ZChannel[Any, ZNothing, Any, Any, ZNothing, Chunk[A], Any] = null
if (chunkBuilder == null) {
chunkBuilder = ChunkBuilder.make(n)
}
while (i < chunkSize) {
chunkBuilder.addOne(chunk(i))
i += 1
pos += 1
if (pos == n) {
buffer ++= chunkBuilder.result()
chunkBuilder.clear()
// Flush buffer
val result = ZChannel.write(buffer)
pos = 0
buffer = Chunk.empty[A]
if (channel == null) channel = result
else channel = channel *> result
}
}
channel
} else {
// Optimized for large chunks
var channel: ZChannel[Any, ZNothing, Any, Any, ZNothing, Chunk[A], Any] = null
var chunkOffset = 0
if (chunkBuilder != null) {
// Last chunk might have been small and written to chunkBuilder,
// so add to buffer before continuing with large chunk
buffer ++= chunkBuilder.result()
chunkBuilder.clear()
}
while (chunkOffset < chunkSize) {
val needed = n - pos
val available = chunkSize - chunkOffset
val size = math.min(needed, available)
buffer ++= chunk.slice(chunkOffset, chunkOffset + size)
pos += size
chunkOffset += size
if (size == needed) {
// Flush buffer
val result = ZChannel.write(buffer)
pos = 0
buffer = Chunk.empty[A]
if (channel == null) channel = result
else channel = channel *> result
}
}
channel
}
}
private def rechunk1(chunk: Chunk[A], len: Int)(implicit
trace: Trace
): ZChannel[Any, ZNothing, Any, Any, ZNothing, Chunk[A], Any] = {
var channel: ZChannel[Any, ZNothing, Any, Any, ZNothing, Chunk[A], Any] = ZChannel.write(Chunk.single(chunk.head))
var i = 1
while (i < len) {
val c = Chunk.single(chunk(i))
channel = channel *> ZChannel.write(c)
i += 1
}
channel
}
def done()(implicit trace: Trace): ZChannel[Any, ZNothing, Any, Any, ZNothing, Chunk[A], Any] = {
// Last chunk might have been small and written to chunkBuilder,
// so add to buffer before last flush
if (chunkBuilder != null) {
buffer ++= chunkBuilder.result()
chunkBuilder.clear()
}
if (isEmpty) ZChannel.unit
else ZChannel.write(buffer)
}
}
private[zio] sealed trait SinkEndReason
private[zio] object SinkEndReason {
case object ScheduleEnd extends SinkEndReason
case object UpstreamEnd extends SinkEndReason
}
private[zio] sealed trait HandoffSignal[E, A]
private[zio] object HandoffSignal {
case class Emit[E, A](els: Chunk[A]) extends HandoffSignal[E, A]
case class Halt[E, A](error: Cause[E]) extends HandoffSignal[E, A]
case class End[E, A](reason: SinkEndReason) extends HandoffSignal[E, A]
}
private[zio] sealed trait DebounceState[+E, +A]
private[zio] object DebounceState {
case object NotStarted extends DebounceState[Nothing, Nothing]
case class Previous[A](fiber: Fiber[Nothing, Chunk[A]]) extends DebounceState[Nothing, A]
case class Current[E, A](fiber: Fiber[E, HandoffSignal[E, A]]) extends DebounceState[E, A]
}
/**
* An `Emit[R, E, A, B]` represents an asynchronous callback that can be
* called multiple times. The callback can be called with a value of type
* `ZIO[R, Option[E], Chunk[A]]`, where succeeding with a `Chunk[A]` indicates
* to emit those elements, failing with `Some[E]` indicates to terminate with
* that error, and failing with `None` indicates to terminate with an end of
* stream signal.
*/
trait Emit[+R, -E, -A, +B] extends (ZIO[R, Option[E], Chunk[A]] => B) {
def apply(v1: ZIO[R, Option[E], Chunk[A]]): B
/**
* Emits a chunk containing the specified values.
*/
def chunk(as: Chunk[A])(implicit trace: Trace): B =
apply(ZIO.succeed(as))
/**
* Terminates with a cause that dies with the specified `Throwable`.
*/
def die(t: Throwable)(implicit trace: Trace): B =
apply(ZIO.die(t))
/**
* Terminates with a cause that dies with a `Throwable` with the specified
* message.
*/
def dieMessage(message: String)(implicit trace: Trace): B =
apply(ZIO.dieMessage(message))
/**
* Either emits the specified value if this `Exit` is a `Success` or else
* terminates with the specified cause if this `Exit` is a `Failure`.
*/
def done(exit: Exit[E, A])(implicit trace: Trace): B =
apply(ZIO.done(exit.mapBothExit(e => Some(e), a => Chunk.single(a))))
/**
* Terminates with an end of stream signal.
*/
def end(implicit trace: Trace): B =
apply(Exit.failNone)
/**
* Terminates with the specified error.
*/
def fail(e: E)(implicit trace: Trace): B =
apply(ZIO.fail(Some(e)))
/**
* Either emits the success value of this effect or terminates the stream
* with the failure value of this effect.
*/
def fromEffect(zio: ZIO[R, E, A])(implicit trace: Trace): B =
apply(zio.mapBoth(e => Some(e), a => Chunk.single(a)))
/**
* Either emits the success value of this effect or terminates the stream
* with the failure value of this effect.
*/
def fromEffectChunk(zio: ZIO[R, E, Chunk[A]])(implicit trace: Trace): B =
apply(zio.mapError(e => Some(e)))
/**
* Terminates the stream with the specified cause.
*/
def halt(cause: Cause[E])(implicit trace: Trace): B =
apply(Exit.failCause(cause.map(e => Some(e))))
/**
* Emits a chunk containing the specified value.
*/
def single(a: A)(implicit trace: Trace): B =
apply(ZIO.succeed(Chunk.single(a)))
}
/**
* Provides extension methods for streams that are sorted by distinct keys.
*/
implicit final class SortedByKey[R, E, K, A](private val self: ZStream[R, E, (K, A)]) {
/**
* Zips this stream that is sorted by distinct keys and the specified stream
* that is sorted by distinct keys to produce a new stream that is sorted by
* distinct keys. Combines values associated with each key into a tuple,
* using the specified values `defaultLeft` and `defaultRight` to fill in
* missing values.
*
* This allows zipping potentially unbounded streams of data by key in
* constant space but the caller is responsible for ensuring that the
* streams are sorted by distinct keys.
*/
def zipAllSortedByKey[R1 <: R, E1 >: E, B](
that: => ZStream[R1, E1, (K, B)]
)(defaultLeft: => A, defaultRight: => B)(implicit
ord: Ordering[K],
trace: Trace
): ZStream[R1, E1, (K, (A, B))] =
zipAllSortedByKeyWith(that)((_, defaultRight), (defaultLeft, _))((_, _))
/**
* Zips this stream that is sorted by distinct keys and the specified stream
* that is sorted by distinct keys to produce a new stream that is sorted by
* distinct keys. Keeps only values from this stream, using the specified
* value `default` to fill in missing values.
*
* This allows zipping potentially unbounded streams of data by key in
* constant space but the caller is responsible for ensuring that the
* streams are sorted by distinct keys.
*/
def zipAllSortedByKeyLeft[R1 <: R, E1 >: E, B](
that: => ZStream[R1, E1, (K, B)]
)(default: => A)(implicit ord: Ordering[K], trace: Trace): ZStream[R1, E1, (K, A)] =
zipAllSortedByKeyWith(that)(identity, _ => default)((a, _) => a)
/**
* Zips this stream that is sorted by distinct keys and the specified stream
* that is sorted by distinct keys to produce a new stream that is sorted by
* distinct keys. Keeps only values from that stream, using the specified
* value `default` to fill in missing values.
*
* This allows zipping potentially unbounded streams of data by key in
* constant space but the caller is responsible for ensuring that the
* streams are sorted by distinct keys.
*/
def zipAllSortedByKeyRight[R1 <: R, E1 >: E, B](
that: => ZStream[R1, E1, (K, B)]
)(default: => B)(implicit ord: Ordering[K], trace: Trace): ZStream[R1, E1, (K, B)] =
zipAllSortedByKeyWith(that)(_ => default, identity)((_, b) => b)
/**
* Zips this stream that is sorted by distinct keys and the specified stream
* that is sorted by distinct keys to produce a new stream that is sorted by
* distinct keys. Uses the functions `left`, `right`, and `both` to handle
* the cases where a key and value exist in this stream, that stream, or
* both streams.
*
* This allows zipping potentially unbounded streams of data by key in
* constant space but the caller is responsible for ensuring that the
* streams are sorted by distinct keys.
*/
def zipAllSortedByKeyWith[R1 <: R, E1 >: E, B, C](
that: => ZStream[R1, E1, (K, B)]
)(left: A => C, right: B => C)(
both: (A, B) => C
)(implicit ord: Ordering[K], trace: Trace): ZStream[R1, E1, (K, C)] = {
sealed trait State
case object DrainLeft extends State
case object DrainRight extends State
case object PullBoth extends State
final case class PullLeft(rightChunk: Chunk[(K, B)]) extends State
final case class PullRight(leftChunk: Chunk[(K, A)]) extends State
def pull(
state: State,
pullLeft: ZIO[R, Option[E], Chunk[(K, A)]],
pullRight: ZIO[R1, Option[E1], Chunk[(K, B)]]
): ZIO[R1, Nothing, Exit[Option[E1], (Chunk[(K, C)], State)]] =
state match {
case DrainLeft =>
pullLeft.fold(
e => Exit.fail(e),
leftChunk => Exit.succeed(leftChunk.map { case (k, a) => (k, left(a)) } -> DrainLeft)
)
case DrainRight =>
pullRight.fold(
e => Exit.fail(e),
rightChunk => Exit.succeed(rightChunk.map { case (k, b) => (k, right(b)) } -> DrainRight)
)
case PullBoth =>
pullLeft.unsome
.zipPar(pullRight.unsome)
.foldZIO(
e => ZIO.succeed(Exit.fail(Some(e))),
{
case (Some(leftChunk), Some(rightChunk)) =>
if (leftChunk.isEmpty && rightChunk.isEmpty) pull(PullBoth, pullLeft, pullRight)
else if (leftChunk.isEmpty) pull(PullLeft(rightChunk), pullLeft, pullRight)
else if (rightChunk.isEmpty) pull(PullRight(leftChunk), pullLeft, pullRight)
else ZIO.succeed(Exit.succeed(mergeSortedByKeyChunk(leftChunk, rightChunk)))
case (Some(leftChunk), None) =>
if (leftChunk.isEmpty) pull(DrainLeft, pullLeft, pullRight)
else ZIO.succeed(Exit.succeed(leftChunk.map { case (k, a) => (k, left(a)) } -> DrainLeft))
case (None, Some(rightChunk)) =>
if (rightChunk.isEmpty) pull(DrainRight, pullLeft, pullRight)
else
ZIO.succeed(Exit.succeed(rightChunk.map { case (k, b) => (k, right(b)) } -> DrainRight))
case (None, None) => ZIO.succeed(Exit.fail(None))
}
)
case PullLeft(rightChunk) =>
pullLeft.foldZIO(
{
case Some(e) => ZIO.succeed(Exit.fail(Some(e)))
case None =>
ZIO.succeed(Exit.succeed(rightChunk.map { case (k, b) => (k, right(b)) } -> DrainRight))
},
leftChunk =>
if (leftChunk.isEmpty) pull(PullLeft(rightChunk), pullLeft, pullRight)
else ZIO.succeed(Exit.succeed(mergeSortedByKeyChunk(leftChunk, rightChunk)))
)
case PullRight(leftChunk) =>
pullRight.foldZIO(
{
case Some(e) => ZIO.succeed(Exit.fail(Some(e)))
case None => ZIO.succeed(Exit.succeed(leftChunk.map { case (k, a) => (k, left(a)) } -> DrainLeft))
},
rightChunk =>
if (rightChunk.isEmpty) pull(PullRight(leftChunk), pullLeft, pullRight)
else ZIO.succeed(Exit.succeed(mergeSortedByKeyChunk(leftChunk, rightChunk)))
)
}
def mergeSortedByKeyChunk(
leftChunk: Chunk[(K, A)],
rightChunk: Chunk[(K, B)]
): (Chunk[(K, C)], State) = {
val builder = ChunkBuilder.make[(K, C)]()
var state = null.asInstanceOf[State]
val leftIterator = leftChunk.iterator
val rightIterator = rightChunk.iterator
var leftTuple = leftIterator.next()
var rightTuple = rightIterator.next()
var k1 = leftTuple._1
var a = leftTuple._2
var k2 = rightTuple._1
var b = rightTuple._2
var loop = true
while (loop) {
val compare = ord.compare(k1, k2)
if (compare == 0) {
builder += k1 -> both(a, b)
if (leftIterator.hasNext && rightIterator.hasNext) {
leftTuple = leftIterator.next()
rightTuple = rightIterator.next()
k1 = leftTuple._1
a = leftTuple._2
k2 = rightTuple._1
b = rightTuple._2
} else if (leftIterator.hasNext) {
state = PullRight(Chunk.fromIterator(leftIterator))
loop = false
} else if (rightIterator.hasNext) {
state = PullLeft(Chunk.fromIterator(rightIterator))
loop = false
} else {
state = PullBoth
loop = false
}
} else if (compare < 0) {
builder += k1 -> left(a)
if (leftIterator.hasNext) {
leftTuple = leftIterator.next()
k1 = leftTuple._1
a = leftTuple._2
} else {
val rightBuilder = ChunkBuilder.make[(K, B)]()
rightBuilder += rightTuple
rightBuilder ++= rightIterator
state = PullLeft(rightBuilder.result())
loop = false
}
} else {
builder += k2 -> right(b)
if (rightIterator.hasNext) {
rightTuple = rightIterator.next()
k2 = rightTuple._1
b = rightTuple._2
} else {
val leftBuilder = ChunkBuilder.make[(K, A)]()
leftBuilder += leftTuple
leftBuilder ++= leftIterator
state = PullRight(leftBuilder.result())
loop = false
}
}
}
(builder.result(), state)
}
self.combineChunks[R1, E1, State, (K, B), (K, C)](that)(PullBoth)(pull)
}
}
private def mapDequeue[A, B](dequeue: Dequeue[A])(f: A => B): Dequeue[B] =
new Dequeue[B] {
def awaitShutdown(implicit trace: Trace): UIO[Unit] =
dequeue.awaitShutdown
def capacity: Int =
dequeue.capacity
def isShutdown(implicit trace: Trace): UIO[Boolean] =
dequeue.isShutdown
def shutdown(implicit trace: Trace): UIO[Unit] =
dequeue.shutdown
def size(implicit trace: Trace): UIO[Int] =
dequeue.size
def take(implicit trace: Trace): UIO[B] =
dequeue.take.map(f)
def takeAll(implicit trace: Trace): UIO[Chunk[B]] =
dequeue.takeAll.map(_.map(f))
def takeUpTo(max: Int)(implicit trace: Trace): UIO[Chunk[B]] =
dequeue.takeUpTo(max).map(_.map(f))
}
/**
* A variant of `groupBy` that retains the insertion order of keys.
*/
private def groupBy[K, V](values: Iterable[V])(f: V => K): Chunk[(K, Chunk[V])] = {
class GroupedBuilder extends Function1[K, ChunkBuilder[V]] { self =>
val builder = ChunkBuilder.make[(K, ChunkBuilder[V])]()
def apply(key: K): ChunkBuilder[V] = {
val builder = ChunkBuilder.make[V]()
self.builder += key -> builder
builder
}
def result(): Chunk[(K, Chunk[V])] = {
val chunk = builder.result()
chunk.map { case (key, builder) => key -> builder.result() }
}
}
val groupedBuilder = new GroupedBuilder
val iterator = values.iterator
val map = mutable.Map.empty[K, ChunkBuilder[V]]
while (iterator.hasNext) {
val value = iterator.next()
val key = f(value)
val builder = map.getOrElseUpdate(key, groupedBuilder(key))
builder += value
}
groupedBuilder.result()
}
private def zipChunks[A, B, C](cl: Chunk[A], cr: Chunk[B], f: (A, B) => C): (Chunk[C], Either[Chunk[A], Chunk[B]]) =
if (cl.size > cr.size)
(cl.take(cr.size).zipWith(cr)(f), Left(cl.drop(cr.size)))
else
(cl.zipWith(cr.take(cl.size))(f), Right(cr.drop(cl.size)))
}
