zio.magic.macros.LayerMacros.scala Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of zio-magic-macros_2.13 Show documentation

Magically construct ZLayers at compile-time (with friendly errors)

The newest version!

package zio.magic.macros

import zio._
import zio.magic.macros.graph.Node
import zio.magic.macros.utils.{CleanCodePrinter, LayerMacroUtils}

import scala.language.experimental.macros
import scala.reflect.macros.blackbox

private[zio] class LayerMacros(val c: blackbox.Context) extends LayerMacroUtils {
  import c.universe._

  def injectImpl[F[_, _, _], R: c.WeakTypeTag, E, A](
      layers: c.Expr[ZLayer[_, E, _]]*
  ): c.Expr[F[Any, E, A]] = {
    assertProperVarArgs(layers)
    val expr = buildMemoizedLayer(generateExprGraph(layers), getRequirements[R])
    c.Expr[F[Any, E, A]](q"${c.prefix}.provideLayerManual(${expr.tree})")
  }

  def injectSomeImpl[F[_, _, _], R0: c.WeakTypeTag, R: c.WeakTypeTag, E, A](
      layers: c.Expr[ZLayer[_, E, _]]*
  ): c.Expr[F[R0, E, A]] = {
    assertProperVarArgs(layers)
    val remainderRequirements = getRequirements[R0]
    val remainderExpr =
      if (weakTypeOf[R0] =:= weakTypeOf[ZEnv]) reify(ZEnv.any)
      else reify(ZLayer.requires[R0])

    val remainderNode = Node(List.empty, remainderRequirements, remainderExpr)
    val nodes         = (remainderNode +: layers.map(getNode)).toList

    val layerExpr = buildMemoizedLayer(generateExprGraph(nodes), getRequirements[R])
    c.Expr[F[R0, E, A]](q"${c.prefix}.provideLayerManual(${layerExpr.tree})")
  }

  def debugGetRequirements[R: c.WeakTypeTag]: c.Expr[List[String]] =
    c.Expr[List[String]](q"${getRequirements[R]}")

  def debugShowTree(any: c.Tree): c.Expr[String] = {
    val string = CleanCodePrinter.show(c)(any)
    c.Expr[String](q"$string")
  }
}

private[zio] object MacroUnitTestUtils {
  def getRequirements[R]: List[String] = macro LayerMacros.debugGetRequirements[R]

  def showTree(any: Any): String = macro LayerMacros.debugShowTree
}