okhttp3.Dispatcher.kt Maven / Gradle / Ivy
/*
* Copyright (C) 2013 Square, Inc.
*
* 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 okhttp3
import okhttp3.RealCall.AsyncCall
import okhttp3.internal.threadFactory
import java.util.ArrayDeque
import java.util.Collections
import java.util.Deque
import java.util.concurrent.ExecutorService
import java.util.concurrent.SynchronousQueue
import java.util.concurrent.ThreadPoolExecutor
import java.util.concurrent.TimeUnit
/**
* Policy on when async requests are executed.
*
* Each dispatcher uses an [ExecutorService] to run calls internally. If you supply your own
* executor, it should be able to run [the configured maximum][maxRequests] number of calls
* concurrently.
*/
class Dispatcher constructor() {
/**
* The maximum number of requests to execute concurrently. Above this requests queue in memory,
* waiting for the running calls to complete.
*
* If more than [maxRequests] requests are in flight when this is invoked, those requests will
* remain in flight.
*/
@get:Synchronized var maxRequests = 64
set(maxRequests) {
require(maxRequests >= 1) { "max < 1: $maxRequests" }
synchronized(this) {
field = maxRequests
}
promoteAndExecute()
}
/**
* The maximum number of requests for each host to execute concurrently. This limits requests by
* the URL's host name. Note that concurrent requests to a single IP address may still exceed this
* limit: multiple hostnames may share an IP address or be routed through the same HTTP proxy.
*
* If more than [maxRequestsPerHost] requests are in flight when this is invoked, those requests
* will remain in flight.
*
* WebSocket connections to hosts **do not** count against this limit.
*/
@get:Synchronized var maxRequestsPerHost = 5
set(maxRequestsPerHost) {
require(maxRequestsPerHost >= 1) { "max < 1: $maxRequestsPerHost" }
synchronized(this) {
field = maxRequestsPerHost
}
promoteAndExecute()
}
/**
* A callback to be invoked each time the dispatcher becomes idle (when the number of running
* calls returns to zero).
*
* Note: The time at which a [call][Call] is considered idle is different depending on whether it
* was run [asynchronously][Call.enqueue] or [synchronously][Call.execute]. Asynchronous calls
* become idle after the [onResponse][Callback.onResponse] or [onFailure][Callback.onFailure]
* callback has returned. Synchronous calls become idle once [execute()][Call.execute] returns.
* This means that if you are doing synchronous calls the network layer will not truly be idle
* until every returned [Response] has been closed.
*/
@set:Synchronized
@get:Synchronized
var idleCallback: Runnable? = null
private var executorServiceOrNull: ExecutorService? = null
@get:Synchronized
@get:JvmName("executorService") val executorService: ExecutorService
get() {
if (executorServiceOrNull == null) {
executorServiceOrNull = ThreadPoolExecutor(0, Int.MAX_VALUE, 60, TimeUnit.SECONDS,
SynchronousQueue(), threadFactory("OkHttp Dispatcher", false))
}
return executorServiceOrNull!!
}
/** Ready async calls in the order they'll be run. */
private val readyAsyncCalls = ArrayDeque()
/** Running asynchronous calls. Includes canceled calls that haven't finished yet. */
private val runningAsyncCalls = ArrayDeque()
/** Running synchronous calls. Includes canceled calls that haven't finished yet. */
private val runningSyncCalls = ArrayDeque()
constructor(executorService: ExecutorService) : this() {
this.executorServiceOrNull = executorService
}
internal fun enqueue(call: AsyncCall) {
synchronized(this) {
readyAsyncCalls.add(call)
// Mutate the AsyncCall so that it shares the AtomicInteger of an existing running call to
// the same host.
if (!call.get().forWebSocket) {
val existingCall = findExistingCallWithHost(call.host())
if (existingCall != null) call.reuseCallsPerHostFrom(existingCall)
}
}
promoteAndExecute()
}
private fun findExistingCallWithHost(host: String): AsyncCall? {
for (existingCall in runningAsyncCalls) {
if (existingCall.host() == host) return existingCall
}
for (existingCall in readyAsyncCalls) {
if (existingCall.host() == host) return existingCall
}
return null
}
/**
* Cancel all calls currently enqueued or executing. Includes calls executed both
* [synchronously][Call.execute] and [asynchronously][Call.enqueue].
*/
@Synchronized fun cancelAll() {
for (call in readyAsyncCalls) {
call.get().cancel()
}
for (call in runningAsyncCalls) {
call.get().cancel()
}
for (call in runningSyncCalls) {
call.cancel()
}
}
/**
* Promotes eligible calls from [readyAsyncCalls] to [runningAsyncCalls] and runs them on the
* executor service. Must not be called with synchronization because executing calls can call
* into user code.
*
* @return true if the dispatcher is currently running calls.
*/
private fun promoteAndExecute(): Boolean {
assert(!Thread.holdsLock(this))
val executableCalls = mutableListOf()
val isRunning: Boolean
synchronized(this) {
val i = readyAsyncCalls.iterator()
while (i.hasNext()) {
val asyncCall = i.next()
if (runningAsyncCalls.size >= this.maxRequests) break // Max capacity.
if (asyncCall.callsPerHost().get() >= this.maxRequestsPerHost) continue // Host max capacity.
i.remove()
asyncCall.callsPerHost().incrementAndGet()
executableCalls.add(asyncCall)
runningAsyncCalls.add(asyncCall)
}
isRunning = runningCallsCount() > 0
}
for (i in 0 until executableCalls.size) {
val asyncCall = executableCalls[i]
asyncCall.executeOn(executorService)
}
return isRunning
}
/** Used by `Call#execute` to signal it is in-flight. */
@Synchronized internal fun executed(call: RealCall) {
runningSyncCalls.add(call)
}
/** Used by `AsyncCall#run` to signal completion. */
internal fun finished(call: AsyncCall) {
call.callsPerHost().decrementAndGet()
finished(runningAsyncCalls, call)
}
/** Used by `Call#execute` to signal completion. */
internal fun finished(call: RealCall) {
finished(runningSyncCalls, call)
}
private fun finished(calls: Deque, call: T) {
val idleCallback: Runnable?
synchronized(this) {
if (!calls.remove(call)) throw AssertionError("Call wasn't in-flight!")
idleCallback = this.idleCallback
}
val isRunning = promoteAndExecute()
if (!isRunning && idleCallback != null) {
idleCallback.run()
}
}
/** Returns a snapshot of the calls currently awaiting execution. */
@Synchronized fun queuedCalls(): List {
return Collections.unmodifiableList(readyAsyncCalls.map { it.get() })
}
/** Returns a snapshot of the calls currently being executed. */
@Synchronized fun runningCalls(): List {
return Collections.unmodifiableList(runningSyncCalls + runningAsyncCalls.map { it.get() })
}
@Synchronized fun queuedCallsCount(): Int = readyAsyncCalls.size
@Synchronized fun runningCallsCount(): Int = runningAsyncCalls.size + runningSyncCalls.size
@JvmName("-deprecated_executorService")
@Deprecated(
message = "moved to val",
replaceWith = ReplaceWith(expression = "executorService"),
level = DeprecationLevel.ERROR)
fun executorService(): ExecutorService = executorService
}