diff options
Diffstat (limited to 'src/main/scala/scala/async/internal/ExprBuilder.scala')
| -rw-r--r-- | src/main/scala/scala/async/internal/ExprBuilder.scala | 73 |
1 files changed, 44 insertions, 29 deletions
diff --git a/src/main/scala/scala/async/internal/ExprBuilder.scala b/src/main/scala/scala/async/internal/ExprBuilder.scala index 3bde51a..438e59e 100644 --- a/src/main/scala/scala/async/internal/ExprBuilder.scala +++ b/src/main/scala/scala/async/internal/ExprBuilder.scala @@ -42,7 +42,7 @@ trait ExprBuilder { } } - /** A sequence of statements the concludes with a unconditional transition to `nextState` */ + /** A sequence of statements that concludes with a unconditional transition to `nextState` */ final class SimpleAsyncState(val stats: List[Tree], val state: Int, nextState: Int, symLookup: SymLookup) extends AsyncState { @@ -65,7 +65,7 @@ trait ExprBuilder { } /** A sequence of statements that concludes with an `await` call. The `onComplete` - * handler will unconditionally transition to `nestState`.`` + * handler will unconditionally transition to `nextState`. */ final class AsyncStateWithAwait(val stats: List[Tree], val state: Int, nextState: Int, val awaitable: Awaitable, symLookup: SymLookup) @@ -110,7 +110,7 @@ trait ExprBuilder { } /* - * Builder for a single state of an async method. + * Builder for a single state of an async expression. */ final class AsyncStateBuilder(state: Int, private val symLookup: SymLookup) { /* Statements preceding an await call. */ @@ -123,9 +123,10 @@ trait ExprBuilder { def addStat() = stats += stat stat match { case Apply(fun, Nil) => + // labelDefStates belongs to the current ExprBuilder labelDefStates get fun.symbol match { - case Some(nextState) => nextJumpState = Some(nextState) - case None => addStat() + case opt @ Some(nextState) => nextJumpState = opt // re-use object + case None => addStat() } case _ => addStat() } @@ -258,7 +259,7 @@ trait ExprBuilder { currState = afterMatchState stateBuilder = new AsyncStateBuilder(currState, symLookup) - case ld@LabelDef(name, params, rhs) if rhs exists isAwait => + case ld @ LabelDef(name, params, rhs) if rhs exists isAwait => val startLabelState = nextState() val afterLabelState = nextState() asyncStates += stateBuilder.resultWithLabel(startLabelState, symLookup) @@ -268,7 +269,8 @@ trait ExprBuilder { currState = afterLabelState stateBuilder = new AsyncStateBuilder(currState, symLookup) - case _ => + + case _ => checkForUnsupportedAwait(stat) stateBuilder += stat } @@ -293,6 +295,13 @@ trait ExprBuilder { gen.mkAttributedRef(stateMachineMember(name)) } + /** + * Uses `AsyncBlockBuilder` to create an instance of `AsyncBlock`. + * + * @param block a `Block` tree in ANF + * @param symLookup helper for looking up members of the state machine class + * @return an `AsyncBlock` + */ def buildAsyncBlock(block: Block, symLookup: SymLookup): AsyncBlock = { val Block(stats, expr) = block val startState = stateAssigner.nextState() @@ -323,19 +332,23 @@ trait ExprBuilder { val initStates = asyncStates.init /** - * def resume(): Unit = { - * try { - * state match { - * case 0 => { - * f11 = exprReturningFuture - * f11.onComplete(onCompleteHandler)(context) + * Builds the definition of the `resume` method. + * + * The resulting tree has the following shape: + * + * def resume(): Unit = { + * try { + * state match { + * case 0 => { + * f11 = exprReturningFuture + * f11.onComplete(onCompleteHandler)(context) + * } + * ... + * } + * } catch { + * case NonFatal(t) => result.failure(t) * } - * ... * } - * } catch { - * case NonFatal(t) => result.failure(t) - * } - * } */ def resumeFunTree[T: WeakTypeTag]: DefDef = DefDef(Modifiers(), name.resume, Nil, List(Nil), Ident(definitions.UnitClass), @@ -344,22 +357,23 @@ trait ExprBuilder { List( CaseDef( Bind(name.t, Ident(nme.WILDCARD)), - Apply(Ident(defn.NonFatalClass), List(Ident(name.t))), - Block(List({ + Apply(Ident(defn.NonFatalClass), List(Ident(name.t))), { val t = Expr[Throwable](Ident(name.t)) futureSystemOps.completeProm[T]( Expr[futureSystem.Prom[T]](symLookup.memberRef(name.result)), reify(scala.util.Failure(t.splice))).tree - }), literalUnit))), EmptyTree)) + })), EmptyTree)) /** - * assumes tr: Try[Any] is in scope. + * Builds a `match` expression used as an onComplete handler. * - * state match { - * case 0 => - * x11 = tr.get.asInstanceOf[Double] - * state = 1 - * resume() - * } + * Assumes `tr: Try[Any]` is in scope. The resulting tree has the following shape: + * + * state match { + * case 0 => + * x11 = tr.get.asInstanceOf[Double] + * state = 1 + * resume() + * } */ def onCompleteHandler[T: WeakTypeTag]: Tree = Match(symLookup.memberRef(name.state), initStates.flatMap(_.mkOnCompleteHandler[T]).toList) @@ -373,7 +387,8 @@ trait ExprBuilder { case class Awaitable(expr: Tree, resultName: Symbol, resultType: Type, resultValDef: ValDef) - private def mkResumeApply(symLookup: SymLookup) = Apply(symLookup.memberRef(name.resume), Nil) + private def mkResumeApply(symLookup: SymLookup) = + Apply(symLookup.memberRef(name.resume), Nil) private def mkStateTree(nextState: Int, symLookup: SymLookup): Tree = Assign(symLookup.memberRef(name.state), Literal(Constant(nextState))) |