1680 lines
57 KiB
Nim
1680 lines
57 KiB
Nim
#
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# Chronos
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#
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# (c) Copyright 2015 Dominik Picheta
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# (c) Copyright 2018-2023 Status Research & Development GmbH
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#
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# Licensed under either of
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# Apache License, version 2.0, (LICENSE-APACHEv2)
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# MIT license (LICENSE-MIT)
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## Features and utilities for `Future` that integrate it with the dispatcher
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## and the rest of the async machinery
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{.push raises: [].}
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import std/[sequtils, macros]
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import stew/base10
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import ./[asyncengine, raisesfutures]
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import ../[config, futures]
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export
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raisesfutures.Raising, raisesfutures.InternalRaisesFuture,
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raisesfutures.init, raisesfutures.error, raisesfutures.readError
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when chronosStackTrace:
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import std/strutils
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when defined(nimHasStacktracesModule):
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import system/stacktraces
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else:
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const
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reraisedFromBegin = -10
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reraisedFromEnd = -100
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template LocCreateIndex*: auto {.deprecated: "LocationKind.Create".} =
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LocationKind.Create
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template LocFinishIndex*: auto {.deprecated: "LocationKind.Finish".} =
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LocationKind.Finish
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template LocCompleteIndex*: untyped {.deprecated: "LocationKind.Finish".} =
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LocationKind.Finish
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func `[]`*(loc: array[LocationKind, ptr SrcLoc], v: int): ptr SrcLoc {.
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deprecated: "use LocationKind".} =
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case v
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of 0: loc[LocationKind.Create]
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of 1: loc[LocationKind.Finish]
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else: raiseAssert("Unknown source location " & $v)
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type
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FutureStr*[T] = ref object of Future[T]
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## Deprecated
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gcholder*: string
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FutureSeq*[A, B] = ref object of Future[A]
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## Deprecated
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gcholder*: seq[B]
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FuturePendingError* = object of FutureError
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## Error raised when trying to `read` a Future that is still pending
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FutureCompletedError* = object of FutureError
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## Error raised when trying access the error of a completed Future
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SomeFuture = Future|InternalRaisesFuture
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func raiseFuturePendingError(fut: FutureBase) {.
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noinline, noreturn, raises: FuturePendingError.} =
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raise (ref FuturePendingError)(msg: "Future is still pending", future: fut)
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func raiseFutureCompletedError(fut: FutureBase) {.
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noinline, noreturn, raises: FutureCompletedError.} =
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raise (ref FutureCompletedError)(
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msg: "Future is completed, cannot read error", future: fut)
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# Backwards compatibility for old FutureState name
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template Finished* {.deprecated: "Use Completed instead".} = Completed
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template Finished*(T: type FutureState): FutureState {.
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deprecated: "Use FutureState.Completed instead".} =
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FutureState.Completed
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proc newFutureImpl[T](loc: ptr SrcLoc): Future[T] =
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let fut = Future[T]()
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internalInitFutureBase(fut, loc, FutureState.Pending, {})
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fut
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proc newFutureImpl[T](loc: ptr SrcLoc, flags: FutureFlags): Future[T] =
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let fut = Future[T]()
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internalInitFutureBase(fut, loc, FutureState.Pending, flags)
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fut
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proc newInternalRaisesFutureImpl[T, E](
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loc: ptr SrcLoc): InternalRaisesFuture[T, E] =
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let fut = InternalRaisesFuture[T, E]()
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internalInitFutureBase(fut, loc, FutureState.Pending, {})
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fut
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proc newInternalRaisesFutureImpl[T, E](
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loc: ptr SrcLoc, flags: FutureFlags): InternalRaisesFuture[T, E] =
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let fut = InternalRaisesFuture[T, E]()
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internalInitFutureBase(fut, loc, FutureState.Pending, flags)
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fut
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proc newFutureSeqImpl[A, B](loc: ptr SrcLoc): FutureSeq[A, B] =
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let fut = FutureSeq[A, B]()
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internalInitFutureBase(fut, loc, FutureState.Pending, {})
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fut
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proc newFutureStrImpl[T](loc: ptr SrcLoc): FutureStr[T] =
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let fut = FutureStr[T]()
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internalInitFutureBase(fut, loc, FutureState.Pending, {})
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fut
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template newFuture*[T](fromProc: static[string] = "",
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flags: static[FutureFlags] = {}): auto =
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## Creates a new future.
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##
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## Specifying ``fromProc``, which is a string specifying the name of the proc
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## that this future belongs to, is a good habit as it helps with debugging.
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when declared(InternalRaisesFutureRaises): # injected by `asyncraises`
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newInternalRaisesFutureImpl[T, InternalRaisesFutureRaises](
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getSrcLocation(fromProc), flags)
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else:
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newFutureImpl[T](getSrcLocation(fromProc), flags)
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template newInternalRaisesFuture*[T, E](fromProc: static[string] = ""): auto =
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## Creates a new future.
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##
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## Specifying ``fromProc``, which is a string specifying the name of the proc
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## that this future belongs to, is a good habit as it helps with debugging.
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newInternalRaisesFutureImpl[T, E](getSrcLocation(fromProc))
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template newFutureSeq*[A, B](fromProc: static[string] = ""): FutureSeq[A, B] {.deprecated.} =
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## Create a new future which can hold/preserve GC sequence until future will
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## not be completed.
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##
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## Specifying ``fromProc``, which is a string specifying the name of the proc
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## that this future belongs to, is a good habit as it helps with debugging.
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newFutureSeqImpl[A, B](getSrcLocation(fromProc))
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template newFutureStr*[T](fromProc: static[string] = ""): FutureStr[T] {.deprecated.} =
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## Create a new future which can hold/preserve GC string until future will
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## not be completed.
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##
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## Specifying ``fromProc``, which is a string specifying the name of the proc
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## that this future belongs to, is a good habit as it helps with debugging.
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newFutureStrImpl[T](getSrcLocation(fromProc))
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proc done*(future: FutureBase): bool {.deprecated: "Use `completed` instead".} =
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## This is an alias for ``completed(future)`` procedure.
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completed(future)
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when chronosFutureTracking:
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proc futureDestructor(udata: pointer) =
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## This procedure will be called when Future[T] got completed, cancelled or
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## failed and all Future[T].callbacks are already scheduled and processed.
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let future = cast[FutureBase](udata)
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if future == futureList.tail: futureList.tail = future.prev
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if future == futureList.head: futureList.head = future.next
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if not(isNil(future.next)): future.next.internalPrev = future.prev
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if not(isNil(future.prev)): future.prev.internalNext = future.next
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futureList.count.dec()
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proc scheduleDestructor(future: FutureBase) {.inline.} =
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callSoon(futureDestructor, cast[pointer](future))
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proc checkFinished(future: FutureBase, loc: ptr SrcLoc) =
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## Checks whether `future` is finished. If it is then raises a
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## ``FutureDefect``.
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if future.finished():
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var msg = ""
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msg.add("An attempt was made to complete a Future more than once. ")
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msg.add("Details:")
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msg.add("\n Future ID: " & Base10.toString(future.id))
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msg.add("\n Creation location:")
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msg.add("\n " & $future.location[LocationKind.Create])
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msg.add("\n First completion location:")
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msg.add("\n " & $future.location[LocationKind.Finish])
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msg.add("\n Second completion location:")
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msg.add("\n " & $loc)
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when chronosStackTrace:
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msg.add("\n Stack trace to moment of creation:")
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msg.add("\n" & indent(future.stackTrace.strip(), 4))
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msg.add("\n Stack trace to moment of secondary completion:")
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msg.add("\n" & indent(getStackTrace().strip(), 4))
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msg.add("\n\n")
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var err = newException(FutureDefect, msg)
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err.cause = future
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raise err
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else:
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future.internalLocation[LocationKind.Finish] = loc
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proc finish(fut: FutureBase, state: FutureState) =
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# We do not perform any checks here, because:
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# 1. `finish()` is a private procedure and `state` is under our control.
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# 2. `fut.state` is checked by `checkFinished()`.
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fut.internalState = state
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fut.internalCancelcb = nil # release cancellation callback memory
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for item in fut.internalCallbacks.mitems():
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if not(isNil(item.function)):
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callSoon(item)
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item = default(AsyncCallback) # release memory as early as possible
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fut.internalCallbacks = default(seq[AsyncCallback]) # release seq as well
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when chronosFutureTracking:
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scheduleDestructor(fut)
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proc complete[T](future: Future[T], val: sink T, loc: ptr SrcLoc) =
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if not(future.cancelled()):
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checkFinished(future, loc)
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doAssert(isNil(future.internalError))
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future.internalValue = chronosMoveSink(val)
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future.finish(FutureState.Completed)
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template complete*[T](future: Future[T], val: sink T) =
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## Completes ``future`` with value ``val``.
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complete(future, val, getSrcLocation())
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proc complete(future: Future[void], loc: ptr SrcLoc) =
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if not(future.cancelled()):
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checkFinished(future, loc)
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doAssert(isNil(future.internalError))
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future.finish(FutureState.Completed)
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template complete*(future: Future[void]) =
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## Completes a void ``future``.
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complete(future, getSrcLocation())
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proc failImpl(
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future: FutureBase, error: ref CatchableError, loc: ptr SrcLoc) =
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if not(future.cancelled()):
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checkFinished(future, loc)
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future.internalError = error
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when chronosStackTrace:
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future.internalErrorStackTrace = if getStackTrace(error) == "":
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getStackTrace()
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else:
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getStackTrace(error)
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future.finish(FutureState.Failed)
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template fail*[T](
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future: Future[T], error: ref CatchableError, warn: static bool = false) =
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## Completes ``future`` with ``error``.
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failImpl(future, error, getSrcLocation())
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template fail*[T, E](
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future: InternalRaisesFuture[T, E], error: ref CatchableError,
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warn: static bool = true) =
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checkRaises(future, E, error, warn)
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failImpl(future, error, getSrcLocation())
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template newCancelledError(): ref CancelledError =
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(ref CancelledError)(msg: "Future operation cancelled!")
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proc cancelAndSchedule(future: FutureBase, loc: ptr SrcLoc) =
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if not(future.finished()):
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checkFinished(future, loc)
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future.internalError = newCancelledError()
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when chronosStackTrace:
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future.internalErrorStackTrace = getStackTrace()
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future.finish(FutureState.Cancelled)
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template cancelAndSchedule*(future: FutureBase) =
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cancelAndSchedule(future, getSrcLocation())
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proc tryCancel(future: FutureBase, loc: ptr SrcLoc): bool =
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## Perform an attempt to cancel ``future``.
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##
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## NOTE: This procedure does not guarantee that cancellation will actually
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## happened.
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##
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## Cancellation is the process which starts from the last ``future``
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## descendent and moves step by step to the parent ``future``. To initiate
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## this process procedure iterates through all non-finished ``future``
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## descendents and tries to find the last one. If last descendent is still
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## pending it will become cancelled and process will be initiated. In such
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## case this procedure returns ``true``.
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##
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## If last descendent future is not pending, this procedure will be unable to
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## initiate cancellation process and so it returns ``false``.
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if future.cancelled():
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return true
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if future.finished():
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return false
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if not(isNil(future.internalChild)):
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# If you hit this assertion, you should have used the `CancelledError`
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# mechanism and/or use a regular `addCallback`
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when chronosStrictFutureAccess:
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doAssert future.internalCancelcb.isNil,
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"futures returned from `{.async.}` functions must not use " &
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"`cancelCallback`"
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tryCancel(future.internalChild, loc)
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else:
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if not(isNil(future.internalCancelcb)):
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future.internalCancelcb(cast[pointer](future))
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if FutureFlag.OwnCancelSchedule notin future.internalFlags:
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cancelAndSchedule(future, loc)
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future.cancelled()
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template tryCancel*(future: FutureBase): bool =
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tryCancel(future, getSrcLocation())
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proc clearCallbacks(future: FutureBase) =
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future.internalCallbacks = default(seq[AsyncCallback])
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proc addCallback*(future: FutureBase, cb: CallbackFunc, udata: pointer) =
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## Adds the callbacks proc to be called when the future completes.
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##
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## If future has already completed then ``cb`` will be called immediately.
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doAssert(not isNil(cb))
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if future.finished():
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callSoon(cb, udata)
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else:
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future.internalCallbacks.add AsyncCallback(function: cb, udata: udata)
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proc addCallback*(future: FutureBase, cb: CallbackFunc) =
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## Adds the callbacks proc to be called when the future completes.
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##
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## If future has already completed then ``cb`` will be called immediately.
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future.addCallback(cb, cast[pointer](future))
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proc removeCallback*(future: FutureBase, cb: CallbackFunc,
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udata: pointer) =
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## Remove future from list of callbacks - this operation may be slow if there
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## are many registered callbacks!
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doAssert(not isNil(cb))
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# Make sure to release memory associated with callback, or reference chains
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# may be created!
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future.internalCallbacks.keepItIf:
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it.function != cb or it.udata != udata
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proc removeCallback*(future: FutureBase, cb: CallbackFunc) =
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future.removeCallback(cb, cast[pointer](future))
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proc `callback=`*(future: FutureBase, cb: CallbackFunc, udata: pointer) =
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## Clears the list of callbacks and sets the callback proc to be called when
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## the future completes.
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##
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## If future has already completed then ``cb`` will be called immediately.
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##
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## It's recommended to use ``addCallback`` or ``then`` instead.
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# ZAH: how about `setLen(1); callbacks[0] = cb`
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future.clearCallbacks
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future.addCallback(cb, udata)
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proc `callback=`*(future: FutureBase, cb: CallbackFunc) =
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## Sets the callback proc to be called when the future completes.
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##
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## If future has already completed then ``cb`` will be called immediately.
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`callback=`(future, cb, cast[pointer](future))
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proc `cancelCallback=`*(future: FutureBase, cb: CallbackFunc) =
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## Sets the callback procedure to be called when the future is cancelled.
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##
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## This callback will be called immediately as ``future.cancel()`` invoked and
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## must be set before future is finished.
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when chronosStrictFutureAccess:
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doAssert not future.finished(),
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"cancellation callback must be set before finishing the future"
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future.internalCancelcb = cb
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{.push stackTrace: off.}
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proc futureContinue*(fut: FutureBase) {.raises: [], gcsafe.}
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proc internalContinue(fut: pointer) {.raises: [], gcsafe.} =
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let asFut = cast[FutureBase](fut)
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GC_unref(asFut)
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futureContinue(asFut)
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|
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proc futureContinue*(fut: FutureBase) {.raises: [], gcsafe.} =
|
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# This function is responsible for calling the closure iterator generated by
|
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# the `{.async.}` transformation either until it has completed its iteration
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#
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# Every call to an `{.async.}` proc is redirected to call this function
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# instead with its original body captured in `fut.closure`.
|
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while true:
|
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# Call closure to make progress on `fut` until it reaches `yield` (inside
|
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# `await` typically) or completes / fails / is cancelled
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let next: FutureBase = fut.internalClosure(fut)
|
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if fut.internalClosure.finished(): # Reached the end of the transformed proc
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break
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|
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if next == nil:
|
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raiseAssert "Async procedure (" & ($fut.location[LocationKind.Create]) &
|
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") yielded `nil`, are you await'ing a `nil` Future?"
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|
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if not next.finished():
|
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# We cannot make progress on `fut` until `next` has finished - schedule
|
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# `fut` to continue running when that happens
|
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GC_ref(fut)
|
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next.addCallback(CallbackFunc(internalContinue), cast[pointer](fut))
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|
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# return here so that we don't remove the closure below
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return
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|
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# Continue while the yielded future is already finished.
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|
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# `futureContinue` will not be called any more for this future so we can
|
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# clean it up
|
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fut.internalClosure = nil
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fut.internalChild = nil
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|
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{.pop.}
|
|
|
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when chronosStackTrace:
|
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template getFilenameProcname(entry: StackTraceEntry): (string, string) =
|
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when compiles(entry.filenameStr) and compiles(entry.procnameStr):
|
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# We can't rely on "entry.filename" and "entry.procname" still being valid
|
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# cstring pointers, because the "string.data" buffers they pointed to might
|
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# be already garbage collected (this entry being a non-shallow copy,
|
|
# "entry.filename" no longer points to "entry.filenameStr.data", but to the
|
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# buffer of the original object).
|
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(entry.filenameStr, entry.procnameStr)
|
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else:
|
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($entry.filename, $entry.procname)
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|
|
|
proc `$`(stackTraceEntries: seq[StackTraceEntry]): string =
|
|
try:
|
|
when defined(nimStackTraceOverride) and declared(addDebuggingInfo):
|
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let entries = addDebuggingInfo(stackTraceEntries)
|
|
else:
|
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let entries = stackTraceEntries
|
|
|
|
# Find longest filename & line number combo for alignment purposes.
|
|
var longestLeft = 0
|
|
for entry in entries:
|
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let (filename, procname) = getFilenameProcname(entry)
|
|
|
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if procname == "": continue
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|
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let leftLen = filename.len + len($entry.line)
|
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if leftLen > longestLeft:
|
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longestLeft = leftLen
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|
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var indent = 2
|
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# Format the entries.
|
|
for entry in entries:
|
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let (filename, procname) = getFilenameProcname(entry)
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|
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if procname == "":
|
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if entry.line == reraisedFromBegin:
|
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result.add(spaces(indent) & "#[\n")
|
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indent.inc(2)
|
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elif entry.line == reraisedFromEnd:
|
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indent.dec(2)
|
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result.add(spaces(indent) & "]#\n")
|
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continue
|
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|
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let left = "$#($#)" % [filename, $entry.line]
|
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result.add((spaces(indent) & "$#$# $#\n") % [
|
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left,
|
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spaces(longestLeft - left.len + 2),
|
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procname
|
|
])
|
|
except ValueError as exc:
|
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return exc.msg # Shouldn't actually happen since we set the formatting
|
|
# string
|
|
|
|
proc injectStacktrace(error: ref Exception) =
|
|
const header = "\nAsync traceback:\n"
|
|
|
|
var exceptionMsg = error.msg
|
|
if header in exceptionMsg:
|
|
# This is messy: extract the original exception message from the msg
|
|
# containing the async traceback.
|
|
let start = exceptionMsg.find(header)
|
|
exceptionMsg = exceptionMsg[0..<start]
|
|
|
|
var newMsg = exceptionMsg & header
|
|
|
|
let entries = getStackTraceEntries(error)
|
|
newMsg.add($entries)
|
|
|
|
newMsg.add("Exception message: " & exceptionMsg & "\n")
|
|
|
|
# # For debugging purposes
|
|
# newMsg.add("Exception type:")
|
|
# for entry in getStackTraceEntries(future.error):
|
|
# newMsg.add "\n" & $entry
|
|
error.msg = newMsg
|
|
|
|
proc deepLineInfo(n: NimNode, p: LineInfo) =
|
|
n.setLineInfo(p)
|
|
for i in 0..<n.len:
|
|
deepLineInfo(n[i], p)
|
|
|
|
macro internalRaiseIfError*(fut: FutureBase, info: typed) =
|
|
# Check the error field of the given future and raise if it's set to non-nil.
|
|
# This is a macro so we can capture the line info from the original call and
|
|
# report the correct line number on exception effect violation
|
|
let
|
|
info = info.lineInfoObj()
|
|
res = quote do:
|
|
if not(isNil(`fut`.internalError)):
|
|
when chronosStackTrace:
|
|
injectStacktrace(`fut`.internalError)
|
|
raise `fut`.internalError
|
|
res.deepLineInfo(info)
|
|
res
|
|
|
|
macro internalRaiseIfError*(fut: InternalRaisesFuture, raises, info: typed) =
|
|
# For InternalRaisesFuture[void, (ValueError, OSError), will do:
|
|
# {.cast(raises: [ValueError, OSError]).}:
|
|
# if isNil(f.error): discard
|
|
# else: raise f.error
|
|
# TODO https://github.com/nim-lang/Nim/issues/22937
|
|
# we cannot `getTypeInst` on the `fut` - when aliases are involved, the
|
|
# generics are lost - so instead, we pass the raises list explicitly
|
|
|
|
let
|
|
info = info.lineInfoObj()
|
|
types = getRaisesTypes(raises)
|
|
|
|
if isNoRaises(types):
|
|
return quote do:
|
|
if not(isNil(`fut`.internalError)):
|
|
# This would indicate a bug in which `error` was set via the non-raising
|
|
# base type
|
|
raiseAssert("Error set on a non-raising future: " & `fut`.internalError.msg)
|
|
|
|
expectKind(types, nnkBracketExpr)
|
|
expectKind(types[0], nnkSym)
|
|
|
|
assert types[0].strVal == "tuple"
|
|
|
|
let
|
|
internalError = nnkDotExpr.newTree(fut, ident "internalError")
|
|
|
|
ifRaise = nnkIfExpr.newTree(
|
|
nnkElifExpr.newTree(
|
|
nnkCall.newTree(ident"isNil", internalError),
|
|
nnkDiscardStmt.newTree(newEmptyNode())
|
|
),
|
|
nnkElseExpr.newTree(
|
|
nnkRaiseStmt.newTree(internalError)
|
|
)
|
|
)
|
|
|
|
res = nnkPragmaBlock.newTree(
|
|
nnkPragma.newTree(
|
|
nnkCast.newTree(
|
|
newEmptyNode(),
|
|
nnkExprColonExpr.newTree(
|
|
ident"raises",
|
|
block:
|
|
var res = nnkBracket.newTree()
|
|
for r in types[1..^1]:
|
|
res.add(r)
|
|
res
|
|
)
|
|
),
|
|
),
|
|
ifRaise
|
|
)
|
|
res.deepLineInfo(info)
|
|
res
|
|
|
|
proc readFinished[T: not void](fut: Future[T]): lent T {.
|
|
raises: [CatchableError].} =
|
|
# Read a future that is known to be finished, avoiding the extra exception
|
|
# effect.
|
|
internalRaiseIfError(fut, fut)
|
|
fut.internalValue
|
|
|
|
proc read*[T: not void](fut: Future[T] ): lent T {.raises: [CatchableError].} =
|
|
## Retrieves the value of `fut`.
|
|
##
|
|
## If the future failed or was cancelled, the corresponding exception will be
|
|
## raised.
|
|
##
|
|
## If the future is still pending, `FuturePendingError` will be raised.
|
|
if not fut.finished():
|
|
raiseFuturePendingError(fut)
|
|
|
|
fut.readFinished()
|
|
|
|
proc read*(fut: Future[void]) {.raises: [CatchableError].} =
|
|
## Checks that `fut` completed.
|
|
##
|
|
## If the future failed or was cancelled, the corresponding exception will be
|
|
## raised.
|
|
##
|
|
## If the future is still pending, `FuturePendingError` will be raised.
|
|
if not fut.finished():
|
|
raiseFuturePendingError(fut)
|
|
|
|
internalRaiseIfError(fut, fut)
|
|
|
|
proc readError*(fut: FutureBase): ref CatchableError {.raises: [FutureError].} =
|
|
## Retrieves the exception of the failed or cancelled `fut`.
|
|
##
|
|
## If the future was completed with a value, `FutureCompletedError` will be
|
|
## raised.
|
|
##
|
|
## If the future is still pending, `FuturePendingError` will be raised.
|
|
if not fut.finished():
|
|
raiseFuturePendingError(fut)
|
|
|
|
if isNil(fut.error):
|
|
raiseFutureCompletedError(fut)
|
|
|
|
fut.error
|
|
|
|
template taskFutureLocation(future: FutureBase): string =
|
|
let loc = future.location[LocationKind.Create]
|
|
"[" & (
|
|
if len(loc.procedure) == 0: "[unspecified]" else: $loc.procedure & "()"
|
|
) & " at " & $loc.file & ":" & $(loc.line) & "]"
|
|
|
|
template taskErrorMessage(future: FutureBase): string =
|
|
"Asynchronous task " & taskFutureLocation(future) &
|
|
" finished with an exception \"" & $future.error.name &
|
|
"\"!\nMessage: " & future.error.msg &
|
|
"\nStack trace: " & future.error.getStackTrace()
|
|
template taskCancelMessage(future: FutureBase): string =
|
|
"Asynchronous task " & taskFutureLocation(future) & " was cancelled!"
|
|
|
|
proc pollFor[F: Future | InternalRaisesFuture](fut: F): F {.raises: [].} =
|
|
# Blocks the current thread of execution until `fut` has finished, returning
|
|
# the given future.
|
|
#
|
|
# Must not be called recursively (from inside `async` procedures).
|
|
#
|
|
# See alse `awaitne`.
|
|
if not(fut.finished()):
|
|
var finished = false
|
|
# Ensure that callbacks currently scheduled on the future run before returning
|
|
proc continuation(udata: pointer) {.gcsafe.} = finished = true
|
|
fut.addCallback(continuation)
|
|
|
|
while not(finished):
|
|
poll()
|
|
|
|
fut
|
|
|
|
proc waitFor*[T: not void](fut: Future[T]): lent T {.raises: [CatchableError].} =
|
|
## Blocks the current thread of execution until `fut` has finished, returning
|
|
## its value.
|
|
##
|
|
## If the future failed or was cancelled, the corresponding exception will be
|
|
## raised.
|
|
##
|
|
## Must not be called recursively (from inside `async` procedures).
|
|
##
|
|
## See also `await`, `Future.read`
|
|
pollFor(fut).readFinished()
|
|
|
|
proc waitFor*(fut: Future[void]) {.raises: [CatchableError].} =
|
|
## Blocks the current thread of execution until `fut` has finished.
|
|
##
|
|
## If the future failed or was cancelled, the corresponding exception will be
|
|
## raised.
|
|
##
|
|
## Must not be called recursively (from inside `async` procedures).
|
|
##
|
|
## See also `await`, `Future.read`
|
|
pollFor(fut).internalRaiseIfError(fut)
|
|
|
|
proc asyncSpawn*(future: Future[void]) =
|
|
## Spawns a new concurrent async task.
|
|
##
|
|
## Tasks may not raise exceptions or be cancelled - a ``Defect`` will be
|
|
## raised when this happens.
|
|
##
|
|
## This should be used instead of ``discard`` and ``asyncCheck`` when calling
|
|
## an ``async`` procedure without ``await``, to ensure exceptions in the
|
|
## returned future are not silently discarded.
|
|
##
|
|
## Note, that if passed ``future`` is already finished, it will be checked
|
|
## and processed immediately.
|
|
doAssert(not isNil(future), "Future is nil")
|
|
|
|
proc cb(data: pointer) =
|
|
if future.failed():
|
|
raise newException(FutureDefect, taskErrorMessage(future))
|
|
elif future.cancelled():
|
|
raise newException(FutureDefect, taskCancelMessage(future))
|
|
|
|
if not(future.finished()):
|
|
# We adding completion callback only if ``future`` is not finished yet.
|
|
future.addCallback(cb)
|
|
else:
|
|
cb(nil)
|
|
|
|
proc asyncCheck*[T](future: Future[T]) {.
|
|
deprecated: "Raises Defect on future failure, fix your code and use" &
|
|
" asyncSpawn!".} =
|
|
## This function used to raise an exception through the `poll` call if
|
|
## the given future failed - there's no way to handle such exceptions so this
|
|
## function is now an alias for `asyncSpawn`
|
|
##
|
|
when T is void:
|
|
asyncSpawn(future)
|
|
else:
|
|
proc cb(data: pointer) =
|
|
if future.failed():
|
|
raise newException(FutureDefect, taskErrorMessage(future))
|
|
elif future.cancelled():
|
|
raise newException(FutureDefect, taskCancelMessage(future))
|
|
|
|
if not(future.finished()):
|
|
# We adding completion callback only if ``future`` is not finished yet.
|
|
future.addCallback(cb)
|
|
else:
|
|
cb(nil)
|
|
|
|
proc asyncDiscard*[T](future: Future[T]) {.
|
|
deprecated: "Use asyncSpawn or `discard await`".} = discard
|
|
## `asyncDiscard` will discard the outcome of the operation - unlike `discard`
|
|
## it also throws away exceptions! Use `asyncSpawn` if you're sure your
|
|
## code doesn't raise exceptions, or `discard await` to ignore successful
|
|
## outcomes
|
|
|
|
proc `and`*[T, Y](fut1: Future[T], fut2: Future[Y]): Future[void] {.
|
|
deprecated: "Use allFutures[T](varargs[Future[T]])".} =
|
|
## Returns a future which will complete once both ``fut1`` and ``fut2``
|
|
## finish.
|
|
##
|
|
## If cancelled, ``fut1`` and ``fut2`` futures WILL NOT BE cancelled.
|
|
var retFuture = newFuture[void]("chronos.`and`")
|
|
proc cb(data: pointer) =
|
|
if not(retFuture.finished()):
|
|
if fut1.finished() and fut2.finished():
|
|
if cast[pointer](fut1) == data:
|
|
if fut1.failed():
|
|
retFuture.fail(fut1.error)
|
|
else:
|
|
retFuture.complete()
|
|
else:
|
|
if fut2.failed():
|
|
retFuture.fail(fut2.error)
|
|
else:
|
|
retFuture.complete()
|
|
fut1.callback = cb
|
|
fut2.callback = cb
|
|
|
|
proc cancellation(udata: pointer) =
|
|
# On cancel we remove all our callbacks only.
|
|
if not(fut1.finished()):
|
|
fut1.removeCallback(cb)
|
|
if not(fut2.finished()):
|
|
fut2.removeCallback(cb)
|
|
|
|
retFuture.cancelCallback = cancellation
|
|
return retFuture
|
|
|
|
template orImpl*[T, Y](fut1: Future[T], fut2: Future[Y]): untyped =
|
|
var cb: proc(udata: pointer) {.gcsafe, raises: [].}
|
|
cb = proc(udata: pointer) {.gcsafe, raises: [].} =
|
|
if not(retFuture.finished()):
|
|
var fut = cast[FutureBase](udata)
|
|
if cast[pointer](fut1) == udata:
|
|
fut2.removeCallback(cb)
|
|
else:
|
|
fut1.removeCallback(cb)
|
|
if fut.failed():
|
|
retFuture.fail(fut.error, warn = false)
|
|
else:
|
|
retFuture.complete()
|
|
|
|
proc cancellation(udata: pointer) =
|
|
# On cancel we remove all our callbacks only.
|
|
if not(fut1.finished()):
|
|
fut1.removeCallback(cb)
|
|
if not(fut2.finished()):
|
|
fut2.removeCallback(cb)
|
|
|
|
if fut1.finished():
|
|
if fut1.failed():
|
|
retFuture.fail(fut1.error, warn = false)
|
|
else:
|
|
retFuture.complete()
|
|
return retFuture
|
|
|
|
if fut2.finished():
|
|
if fut2.failed():
|
|
retFuture.fail(fut2.error, warn = false)
|
|
else:
|
|
retFuture.complete()
|
|
return retFuture
|
|
|
|
fut1.addCallback(cb)
|
|
fut2.addCallback(cb)
|
|
|
|
retFuture.cancelCallback = cancellation
|
|
return retFuture
|
|
|
|
proc `or`*[T, Y](fut1: Future[T], fut2: Future[Y]): Future[void] =
|
|
## Returns a future which will complete once either ``fut1`` or ``fut2``
|
|
## finish.
|
|
##
|
|
## If ``fut1`` or ``fut2`` future is failed, the result future will also be
|
|
## failed with an error stored in ``fut1`` or ``fut2`` respectively.
|
|
##
|
|
## If both ``fut1`` and ``fut2`` future are completed or failed, the result
|
|
## future will depend on the state of ``fut1`` future. So if ``fut1`` future
|
|
## is failed, the result future will also be failed, if ``fut1`` future is
|
|
## completed, the result future will also be completed.
|
|
##
|
|
## If cancelled, ``fut1`` and ``fut2`` futures WILL NOT BE cancelled.
|
|
var retFuture = newFuture[void]("chronos.or")
|
|
orImpl(fut1, fut2)
|
|
|
|
|
|
proc all*[T](futs: varargs[Future[T]]): auto {.
|
|
deprecated: "Use allFutures(varargs[Future[T]])".} =
|
|
## Returns a future which will complete once all futures in ``futs`` finish.
|
|
## If the argument is empty, the returned future completes immediately.
|
|
##
|
|
## If the awaited futures are not ``Future[void]``, the returned future
|
|
## will hold the values of all awaited futures in a sequence.
|
|
##
|
|
## If the awaited futures *are* ``Future[void]``, this proc returns
|
|
## ``Future[void]``.
|
|
##
|
|
## Note, that if one of the futures in ``futs`` will fail, result of ``all()``
|
|
## will also be failed with error from failed future.
|
|
##
|
|
## TODO: This procedure has bug on handling cancelled futures from ``futs``.
|
|
## So if future from ``futs`` list become cancelled, what must be returned?
|
|
## You can't cancel result ``retFuture`` because in such way infinite
|
|
## recursion will happen.
|
|
let totalFutures = len(futs)
|
|
var completedFutures = 0
|
|
|
|
# Because we can't capture varargs[T] in closures we need to create copy.
|
|
var nfuts = @futs
|
|
|
|
when T is void:
|
|
var retFuture = newFuture[void]("chronos.all(void)")
|
|
proc cb(udata: pointer) =
|
|
if not(retFuture.finished()):
|
|
inc(completedFutures)
|
|
if completedFutures == totalFutures:
|
|
for nfut in nfuts:
|
|
if nfut.failed():
|
|
retFuture.fail(nfut.error)
|
|
break
|
|
if not(retFuture.failed()):
|
|
retFuture.complete()
|
|
|
|
for fut in nfuts:
|
|
fut.addCallback(cb)
|
|
|
|
if len(nfuts) == 0:
|
|
retFuture.complete()
|
|
|
|
return retFuture
|
|
else:
|
|
var retFuture = newFuture[seq[T]]("chronos.all(T)")
|
|
var retValues = newSeq[T](totalFutures)
|
|
|
|
proc cb(udata: pointer) =
|
|
if not(retFuture.finished()):
|
|
inc(completedFutures)
|
|
if completedFutures == totalFutures:
|
|
for k, nfut in nfuts:
|
|
if nfut.failed():
|
|
retFuture.fail(nfut.error)
|
|
break
|
|
else:
|
|
retValues[k] = nfut.value
|
|
if not(retFuture.failed()):
|
|
retFuture.complete(retValues)
|
|
|
|
for fut in nfuts:
|
|
fut.addCallback(cb)
|
|
|
|
if len(nfuts) == 0:
|
|
retFuture.complete(retValues)
|
|
|
|
return retFuture
|
|
|
|
proc oneIndex*[T](futs: varargs[Future[T]]): Future[int] {.
|
|
deprecated: "Use one[T](varargs[Future[T]])".} =
|
|
## Returns a future which will complete once one of the futures in ``futs``
|
|
## complete.
|
|
##
|
|
## If the argument is empty, the returned future FAILS immediately.
|
|
##
|
|
## Returned future will hold index of completed/failed future in ``futs``
|
|
## argument.
|
|
var nfuts = @futs
|
|
var retFuture = newFuture[int]("chronos.oneIndex(T)")
|
|
|
|
proc cb(udata: pointer) =
|
|
var res = -1
|
|
if not(retFuture.finished()):
|
|
var rfut = cast[FutureBase](udata)
|
|
for i in 0..<len(nfuts):
|
|
if cast[FutureBase](nfuts[i]) != rfut:
|
|
nfuts[i].removeCallback(cb)
|
|
else:
|
|
res = i
|
|
retFuture.complete(res)
|
|
|
|
for fut in nfuts:
|
|
fut.addCallback(cb)
|
|
|
|
if len(nfuts) == 0:
|
|
retFuture.fail(newException(ValueError, "Empty Future[T] list"))
|
|
|
|
return retFuture
|
|
|
|
proc oneValue*[T](futs: varargs[Future[T]]): Future[T] {.
|
|
deprecated: "Use one[T](varargs[Future[T]])".} =
|
|
## Returns a future which will finish once one of the futures in ``futs``
|
|
## finish.
|
|
##
|
|
## If the argument is empty, returned future FAILS immediately.
|
|
##
|
|
## Returned future will hold value of completed ``futs`` future, or error
|
|
## if future was failed.
|
|
var nfuts = @futs
|
|
var retFuture = newFuture[T]("chronos.oneValue(T)")
|
|
|
|
proc cb(udata: pointer) =
|
|
var resFut: Future[T]
|
|
if not(retFuture.finished()):
|
|
var rfut = cast[FutureBase](udata)
|
|
for i in 0..<len(nfuts):
|
|
if cast[FutureBase](nfuts[i]) != rfut:
|
|
nfuts[i].removeCallback(cb)
|
|
else:
|
|
resFut = nfuts[i]
|
|
if resFut.failed():
|
|
retFuture.fail(resFut.error)
|
|
else:
|
|
when T is void:
|
|
retFuture.complete()
|
|
else:
|
|
retFuture.complete(resFut.read())
|
|
|
|
for fut in nfuts:
|
|
fut.addCallback(cb)
|
|
|
|
if len(nfuts) == 0:
|
|
retFuture.fail(newException(ValueError, "Empty Future[T] list"))
|
|
|
|
return retFuture
|
|
|
|
proc cancelSoon(future: FutureBase, aftercb: CallbackFunc, udata: pointer,
|
|
loc: ptr SrcLoc) {.raises: [].} =
|
|
## Perform cancellation ``future`` and call ``aftercb`` callback when
|
|
## ``future`` become finished (completed with value, failed or cancelled).
|
|
##
|
|
## NOTE: Compared to the `tryCancel()` call, this procedure call guarantees
|
|
## that ``future``will be finished (completed with value, failed or cancelled)
|
|
## as quickly as possible.
|
|
proc checktick(udata: pointer) {.gcsafe, raises: [].} =
|
|
# We trying to cancel Future on more time, and if `cancel()` succeeds we
|
|
# return early.
|
|
if tryCancel(future, loc):
|
|
return
|
|
# Cancellation signal was not delivered, so we trying to deliver it one
|
|
# more time after one tick. But we need to check situation when child
|
|
# future was finished but our completion callback is not yet invoked.
|
|
if not(future.finished()):
|
|
internalCallTick(checktick)
|
|
|
|
proc continuation(udata: pointer) {.gcsafe.} =
|
|
# We do not use `callSoon` here because we was just scheduled from `poll()`.
|
|
if not(isNil(aftercb)):
|
|
aftercb(udata)
|
|
|
|
if future.finished():
|
|
# We could not schedule callback directly otherwise we could fall into
|
|
# recursion problem.
|
|
if not(isNil(aftercb)):
|
|
let loop = getThreadDispatcher()
|
|
loop.callbacks.addLast(AsyncCallback(function: aftercb, udata: udata))
|
|
return
|
|
|
|
future.addCallback(continuation)
|
|
# Initiate cancellation process.
|
|
if not(tryCancel(future, loc)):
|
|
# Cancellation signal was not delivered, so we trying to deliver it one
|
|
# more time after async tick. But we need to check case, when future was
|
|
# finished but our completion callback is not yet invoked.
|
|
if not(future.finished()):
|
|
internalCallTick(checktick)
|
|
|
|
template cancelSoon*(fut: FutureBase, cb: CallbackFunc, udata: pointer) =
|
|
cancelSoon(fut, cb, udata, getSrcLocation())
|
|
|
|
template cancelSoon*(fut: FutureBase, cb: CallbackFunc) =
|
|
cancelSoon(fut, cb, nil, getSrcLocation())
|
|
|
|
template cancelSoon*(fut: FutureBase, acb: AsyncCallback) =
|
|
cancelSoon(fut, acb.function, acb.udata, getSrcLocation())
|
|
|
|
template cancelSoon*(fut: FutureBase) =
|
|
cancelSoon(fut, nil, nil, getSrcLocation())
|
|
|
|
template cancel*(future: FutureBase) {.
|
|
deprecated: "Please use cancelSoon() or cancelAndWait() instead".} =
|
|
## Cancel ``future``.
|
|
cancelSoon(future, nil, nil, getSrcLocation())
|
|
|
|
proc cancelAndWait*(future: FutureBase, loc: ptr SrcLoc): Future[void] {.
|
|
async: (raw: true, raises: []).} =
|
|
## Perform cancellation ``future`` return Future which will be completed when
|
|
## ``future`` become finished (completed with value, failed or cancelled).
|
|
##
|
|
## NOTE: Compared to the `tryCancel()` call, this procedure call guarantees
|
|
## that ``future``will be finished (completed with value, failed or cancelled)
|
|
## as quickly as possible.
|
|
let retFuture = newFuture[void]("chronos.cancelAndWait(FutureBase)",
|
|
{FutureFlag.OwnCancelSchedule})
|
|
|
|
proc continuation(udata: pointer) {.gcsafe.} =
|
|
retFuture.complete()
|
|
|
|
if future.finished():
|
|
retFuture.complete()
|
|
else:
|
|
retFuture.cancelCallback = nil
|
|
cancelSoon(future, continuation, cast[pointer](retFuture), loc)
|
|
|
|
retFuture
|
|
|
|
template cancelAndWait*(future: FutureBase): Future[void].Raising([]) =
|
|
## Cancel ``future``.
|
|
cancelAndWait(future, getSrcLocation())
|
|
|
|
proc noCancel*[F: SomeFuture](future: F): auto = # async: (raw: true, raises: asyncraiseOf(future) - CancelledError
|
|
## Prevent cancellation requests from propagating to ``future`` while
|
|
## forwarding its value or error when it finishes.
|
|
##
|
|
## This procedure should be used when you need to perform operations which
|
|
## should not be cancelled at all cost, for example closing sockets, pipes,
|
|
## connections or servers. Usually it become useful in exception or finally
|
|
## blocks.
|
|
when F is InternalRaisesFuture:
|
|
type
|
|
E = F.E
|
|
InternalRaisesFutureRaises = E.remove(CancelledError)
|
|
|
|
let retFuture = newFuture[F.T]("chronos.noCancel(T)",
|
|
{FutureFlag.OwnCancelSchedule})
|
|
template completeFuture() =
|
|
if future.completed():
|
|
when F.T is void:
|
|
retFuture.complete()
|
|
else:
|
|
retFuture.complete(future.value)
|
|
elif future.failed():
|
|
when F is Future:
|
|
retFuture.fail(future.error, warn = false)
|
|
when declared(InternalRaisesFutureRaises):
|
|
when InternalRaisesFutureRaises isnot void:
|
|
retFuture.fail(future.error, warn = false)
|
|
else:
|
|
raiseAssert("Unexpected future state [" & $future.state & "]")
|
|
|
|
proc continuation(udata: pointer) {.gcsafe.} =
|
|
completeFuture()
|
|
|
|
if future.finished():
|
|
completeFuture()
|
|
else:
|
|
retFuture.cancelCallback = nil
|
|
future.addCallback(continuation)
|
|
retFuture
|
|
|
|
proc allFutures*(futs: varargs[FutureBase]): Future[void] {.
|
|
async: (raw: true, raises: [CancelledError]).} =
|
|
## Returns a future which will complete only when all futures in ``futs``
|
|
## will be completed, failed or canceled.
|
|
##
|
|
## If the argument is empty, the returned future COMPLETES immediately.
|
|
##
|
|
## On cancel all the awaited futures ``futs`` WILL NOT BE cancelled.
|
|
var retFuture = newFuture[void]("chronos.allFutures()")
|
|
let totalFutures = len(futs)
|
|
var finishedFutures = 0
|
|
|
|
# Because we can't capture varargs[T] in closures we need to create copy.
|
|
var nfuts = @futs
|
|
|
|
proc cb(udata: pointer) =
|
|
if not(retFuture.finished()):
|
|
inc(finishedFutures)
|
|
if finishedFutures == totalFutures:
|
|
retFuture.complete()
|
|
|
|
proc cancellation(udata: pointer) =
|
|
# On cancel we remove all our callbacks only.
|
|
for i in 0..<len(nfuts):
|
|
if not(nfuts[i].finished()):
|
|
nfuts[i].removeCallback(cb)
|
|
|
|
for fut in nfuts:
|
|
if not(fut.finished()):
|
|
fut.addCallback(cb)
|
|
else:
|
|
inc(finishedFutures)
|
|
|
|
retFuture.cancelCallback = cancellation
|
|
if len(nfuts) == 0 or len(nfuts) == finishedFutures:
|
|
retFuture.complete()
|
|
|
|
retFuture
|
|
|
|
proc allFutures*[T](futs: varargs[Future[T]]): Future[void] {.
|
|
async: (raw: true, raises: [CancelledError]).} =
|
|
## Returns a future which will complete only when all futures in ``futs``
|
|
## will be completed, failed or canceled.
|
|
##
|
|
## If the argument is empty, the returned future COMPLETES immediately.
|
|
##
|
|
## On cancel all the awaited futures ``futs`` WILL NOT BE cancelled.
|
|
# Because we can't capture varargs[T] in closures we need to create copy.
|
|
allFutures(futs.mapIt(FutureBase(it)))
|
|
|
|
proc allFutures*[T, E](futs: varargs[InternalRaisesFuture[T, E]]): Future[void] {.
|
|
async: (raw: true, raises: [CancelledError]).} =
|
|
## Returns a future which will complete only when all futures in ``futs``
|
|
## will be completed, failed or canceled.
|
|
##
|
|
## If the argument is empty, the returned future COMPLETES immediately.
|
|
##
|
|
## On cancel all the awaited futures ``futs`` WILL NOT BE cancelled.
|
|
# Because we can't capture varargs[T] in closures we need to create copy.
|
|
allFutures(futs.mapIt(FutureBase(it)))
|
|
|
|
proc allFinished*[F: SomeFuture](futs: varargs[F]): Future[seq[F]] {.
|
|
async: (raw: true, raises: [CancelledError]).} =
|
|
## Returns a future which will complete only when all futures in ``futs``
|
|
## will be completed, failed or canceled.
|
|
##
|
|
## Returned sequence will hold all the Future[T] objects passed to
|
|
## ``allFinished`` with the order preserved.
|
|
##
|
|
## If the argument is empty, the returned future COMPLETES immediately.
|
|
##
|
|
## On cancel all the awaited futures ``futs`` WILL NOT BE cancelled.
|
|
var retFuture = newFuture[seq[F]]("chronos.allFinished()")
|
|
let totalFutures = len(futs)
|
|
var finishedFutures = 0
|
|
|
|
var nfuts = @futs
|
|
|
|
proc cb(udata: pointer) =
|
|
if not(retFuture.finished()):
|
|
inc(finishedFutures)
|
|
if finishedFutures == totalFutures:
|
|
retFuture.complete(nfuts)
|
|
|
|
proc cancellation(udata: pointer) =
|
|
# On cancel we remove all our callbacks only.
|
|
for fut in nfuts.mitems():
|
|
if not(fut.finished()):
|
|
fut.removeCallback(cb)
|
|
|
|
for fut in nfuts:
|
|
if not(fut.finished()):
|
|
fut.addCallback(cb)
|
|
else:
|
|
inc(finishedFutures)
|
|
|
|
retFuture.cancelCallback = cancellation
|
|
if len(nfuts) == 0 or len(nfuts) == finishedFutures:
|
|
retFuture.complete(nfuts)
|
|
|
|
return retFuture
|
|
|
|
proc one*[F: SomeFuture](futs: varargs[F]): Future[F] {.
|
|
async: (raw: true, raises: [ValueError, CancelledError]).} =
|
|
## Returns a future which will complete and return completed Future[T] inside,
|
|
## when one of the futures in ``futs`` will be completed, failed or canceled.
|
|
##
|
|
## If the argument is empty, the returned future FAILS immediately.
|
|
##
|
|
## On success returned Future will hold finished Future[T].
|
|
##
|
|
## On cancel futures in ``futs`` WILL NOT BE cancelled.
|
|
var retFuture = newFuture[F]("chronos.one()")
|
|
|
|
if len(futs) == 0:
|
|
retFuture.fail(newException(ValueError, "Empty Future[T] list"))
|
|
return retFuture
|
|
|
|
# If one of the Future[T] already finished we return it as result
|
|
for fut in futs:
|
|
if fut.finished():
|
|
retFuture.complete(fut)
|
|
return retFuture
|
|
|
|
# Because we can't capture varargs[T] in closures we need to create copy.
|
|
var nfuts = @futs
|
|
|
|
var cb: proc(udata: pointer) {.gcsafe, raises: [].}
|
|
cb = proc(udata: pointer) {.gcsafe, raises: [].} =
|
|
if not(retFuture.finished()):
|
|
var res: F
|
|
var rfut = cast[FutureBase](udata)
|
|
for i in 0..<len(nfuts):
|
|
if cast[FutureBase](nfuts[i]) != rfut:
|
|
nfuts[i].removeCallback(cb)
|
|
else:
|
|
res = nfuts[i]
|
|
retFuture.complete(res)
|
|
|
|
proc cancellation(udata: pointer) =
|
|
# On cancel we remove all our callbacks only.
|
|
for i in 0..<len(nfuts):
|
|
if not(nfuts[i].finished()):
|
|
nfuts[i].removeCallback(cb)
|
|
|
|
for fut in nfuts:
|
|
fut.addCallback(cb)
|
|
|
|
retFuture.cancelCallback = cancellation
|
|
return retFuture
|
|
|
|
proc race*(futs: varargs[FutureBase]): Future[FutureBase] {.
|
|
async: (raw: true, raises: [ValueError, CancelledError]).} =
|
|
## Returns a future which will complete and return completed FutureBase,
|
|
## when one of the futures in ``futs`` will be completed, failed or canceled.
|
|
##
|
|
## If the argument is empty, the returned future FAILS immediately.
|
|
##
|
|
## On success returned Future will hold finished FutureBase.
|
|
##
|
|
## On cancel futures in ``futs`` WILL NOT BE cancelled.
|
|
let retFuture = newFuture[FutureBase]("chronos.race()")
|
|
|
|
if len(futs) == 0:
|
|
retFuture.fail(newException(ValueError, "Empty Future[T] list"))
|
|
return retFuture
|
|
|
|
# If one of the Future[T] already finished we return it as result
|
|
for fut in futs:
|
|
if fut.finished():
|
|
retFuture.complete(fut)
|
|
return retFuture
|
|
|
|
# Because we can't capture varargs[T] in closures we need to create copy.
|
|
var nfuts = @futs
|
|
|
|
var cb: proc(udata: pointer) {.gcsafe, raises: [].}
|
|
cb = proc(udata: pointer) {.gcsafe, raises: [].} =
|
|
if not(retFuture.finished()):
|
|
var res: FutureBase
|
|
var rfut = cast[FutureBase](udata)
|
|
for i in 0..<len(nfuts):
|
|
if nfuts[i] != rfut:
|
|
nfuts[i].removeCallback(cb)
|
|
else:
|
|
res = nfuts[i]
|
|
retFuture.complete(res)
|
|
|
|
proc cancellation(udata: pointer) =
|
|
# On cancel we remove all our callbacks only.
|
|
for i in 0..<len(nfuts):
|
|
if not(nfuts[i].finished()):
|
|
nfuts[i].removeCallback(cb)
|
|
|
|
for fut in nfuts:
|
|
fut.addCallback(cb, cast[pointer](fut))
|
|
|
|
retFuture.cancelCallback = cancellation
|
|
|
|
return retFuture
|
|
|
|
proc race*[T](futs: varargs[Future[T]]): Future[FutureBase] {.
|
|
async: (raw: true, raises: [ValueError, CancelledError]).} =
|
|
## Returns a future which will complete only when all futures in ``futs``
|
|
## will be completed, failed or canceled.
|
|
##
|
|
## If the argument is empty, the returned future COMPLETES immediately.
|
|
##
|
|
## On cancel all the awaited futures ``futs`` WILL NOT BE cancelled.
|
|
# Because we can't capture varargs[T] in closures we need to create copy.
|
|
race(futs.mapIt(FutureBase(it)))
|
|
|
|
proc race*[T, E](futs: varargs[InternalRaisesFuture[T, E]]): Future[FutureBase] {.
|
|
async: (raw: true, raises: [ValueError, CancelledError]).} =
|
|
## Returns a future which will complete only when all futures in ``futs``
|
|
## will be completed, failed or canceled.
|
|
##
|
|
## If the argument is empty, the returned future COMPLETES immediately.
|
|
##
|
|
## On cancel all the awaited futures ``futs`` WILL NOT BE cancelled.
|
|
# Because we can't capture varargs[T] in closures we need to create copy.
|
|
race(futs.mapIt(FutureBase(it)))
|
|
|
|
when (chronosEventEngine in ["epoll", "kqueue"]) or defined(windows):
|
|
import std/os
|
|
|
|
proc waitSignal*(signal: int): Future[void] {.
|
|
async: (raw: true, raises: [AsyncError, CancelledError]).} =
|
|
var retFuture = newFuture[void]("chronos.waitSignal()")
|
|
var signalHandle: Opt[SignalHandle]
|
|
|
|
template getSignalException(e: OSErrorCode): untyped =
|
|
newException(AsyncError, "Could not manipulate signal handler, " &
|
|
"reason [" & $int(e) & "]: " & osErrorMsg(e))
|
|
|
|
proc continuation(udata: pointer) {.gcsafe.} =
|
|
if not(retFuture.finished()):
|
|
if signalHandle.isSome():
|
|
let res = removeSignal2(signalHandle.get())
|
|
if res.isErr():
|
|
retFuture.fail(getSignalException(res.error()))
|
|
else:
|
|
retFuture.complete()
|
|
|
|
proc cancellation(udata: pointer) {.gcsafe.} =
|
|
if not(retFuture.finished()):
|
|
if signalHandle.isSome():
|
|
let res = removeSignal2(signalHandle.get())
|
|
if res.isErr():
|
|
retFuture.fail(getSignalException(res.error()))
|
|
|
|
signalHandle =
|
|
block:
|
|
let res = addSignal2(signal, continuation)
|
|
if res.isErr():
|
|
retFuture.fail(getSignalException(res.error()))
|
|
Opt.some(res.get())
|
|
|
|
retFuture.cancelCallback = cancellation
|
|
retFuture
|
|
|
|
proc sleepAsync*(duration: Duration): Future[void] {.
|
|
async: (raw: true, raises: [CancelledError]).} =
|
|
## Suspends the execution of the current async procedure for the next
|
|
## ``duration`` time.
|
|
var retFuture = newFuture[void]("chronos.sleepAsync(Duration)")
|
|
let moment = Moment.fromNow(duration)
|
|
var timer: TimerCallback
|
|
|
|
proc completion(data: pointer) {.gcsafe.} =
|
|
if not(retFuture.finished()):
|
|
retFuture.complete()
|
|
|
|
proc cancellation(udata: pointer) {.gcsafe.} =
|
|
if not(retFuture.finished()):
|
|
clearTimer(timer)
|
|
|
|
retFuture.cancelCallback = cancellation
|
|
timer = setTimer(moment, completion, cast[pointer](retFuture))
|
|
return retFuture
|
|
|
|
proc sleepAsync*(ms: int): Future[void] {.
|
|
inline, deprecated: "Use sleepAsync(Duration)",
|
|
async: (raw: true, raises: [CancelledError]).} =
|
|
result = sleepAsync(ms.milliseconds())
|
|
|
|
proc stepsAsync*(number: int): Future[void] {.
|
|
async: (raw: true, raises: [CancelledError]).} =
|
|
## Suspends the execution of the current async procedure for the next
|
|
## ``number`` of asynchronous steps (``poll()`` calls).
|
|
##
|
|
## This primitive can be useful when you need to create more deterministic
|
|
## tests and cases.
|
|
doAssert(number > 0, "Number should be positive integer")
|
|
var
|
|
retFuture = newFuture[void]("chronos.stepsAsync(int)")
|
|
counter = 0
|
|
continuation: proc(data: pointer) {.gcsafe, raises: [].}
|
|
|
|
continuation = proc(data: pointer) {.gcsafe, raises: [].} =
|
|
if not(retFuture.finished()):
|
|
inc(counter)
|
|
if counter < number:
|
|
internalCallTick(continuation)
|
|
else:
|
|
retFuture.complete()
|
|
|
|
if number <= 0:
|
|
retFuture.complete()
|
|
else:
|
|
internalCallTick(continuation)
|
|
|
|
retFuture
|
|
|
|
proc idleAsync*(): Future[void] {.
|
|
async: (raw: true, raises: [CancelledError]).} =
|
|
## Suspends the execution of the current asynchronous task until "idle" time.
|
|
##
|
|
## "idle" time its moment of time, when no network events were processed by
|
|
## ``poll()`` call.
|
|
var retFuture = newFuture[void]("chronos.idleAsync()")
|
|
|
|
proc continuation(data: pointer) {.gcsafe.} =
|
|
if not(retFuture.finished()):
|
|
retFuture.complete()
|
|
|
|
proc cancellation(udata: pointer) {.gcsafe.} =
|
|
discard
|
|
|
|
retFuture.cancelCallback = cancellation
|
|
callIdle(continuation, nil)
|
|
retFuture
|
|
|
|
proc withTimeout*[T](fut: Future[T], timeout: Duration): Future[bool] {.
|
|
async: (raw: true, raises: [CancelledError]).} =
|
|
## Returns a future which will complete once ``fut`` completes or after
|
|
## ``timeout`` milliseconds has elapsed.
|
|
##
|
|
## If ``fut`` completes first the returned future will hold true,
|
|
## otherwise, if ``timeout`` milliseconds has elapsed first, the returned
|
|
## future will hold false.
|
|
var
|
|
retFuture = newFuture[bool]("chronos.withTimeout",
|
|
{FutureFlag.OwnCancelSchedule})
|
|
moment: Moment
|
|
timer: TimerCallback
|
|
timeouted = false
|
|
|
|
template completeFuture(fut: untyped): untyped =
|
|
if fut.failed() or fut.completed():
|
|
retFuture.complete(true)
|
|
else:
|
|
retFuture.cancelAndSchedule()
|
|
|
|
# TODO: raises annotation shouldn't be needed, but likely similar issue as
|
|
# https://github.com/nim-lang/Nim/issues/17369
|
|
proc continuation(udata: pointer) {.gcsafe, raises: [].} =
|
|
if not(retFuture.finished()):
|
|
if timeouted:
|
|
retFuture.complete(false)
|
|
return
|
|
if not(fut.finished()):
|
|
# Timer exceeded first, we going to cancel `fut` and wait until it
|
|
# not completes.
|
|
timeouted = true
|
|
fut.cancelSoon()
|
|
else:
|
|
# Future `fut` completed/failed/cancelled first.
|
|
if not(isNil(timer)):
|
|
clearTimer(timer)
|
|
fut.completeFuture()
|
|
|
|
# TODO: raises annotation shouldn't be needed, but likely similar issue as
|
|
# https://github.com/nim-lang/Nim/issues/17369
|
|
proc cancellation(udata: pointer) {.gcsafe, raises: [].} =
|
|
if not(fut.finished()):
|
|
if not isNil(timer):
|
|
clearTimer(timer)
|
|
fut.cancelSoon()
|
|
else:
|
|
fut.completeFuture()
|
|
|
|
if fut.finished():
|
|
retFuture.complete(true)
|
|
else:
|
|
if timeout.isZero():
|
|
retFuture.complete(false)
|
|
elif timeout.isInfinite():
|
|
retFuture.cancelCallback = cancellation
|
|
fut.addCallback(continuation)
|
|
else:
|
|
moment = Moment.fromNow(timeout)
|
|
retFuture.cancelCallback = cancellation
|
|
timer = setTimer(moment, continuation, nil)
|
|
fut.addCallback(continuation)
|
|
|
|
retFuture
|
|
|
|
proc withTimeout*[T](fut: Future[T], timeout: int): Future[bool] {.
|
|
inline, deprecated: "Use withTimeout(Future[T], Duration)".} =
|
|
withTimeout(fut, timeout.milliseconds())
|
|
|
|
proc waitImpl[F: SomeFuture](fut: F, retFuture: auto, timeout: Duration): auto =
|
|
var
|
|
moment: Moment
|
|
timer: TimerCallback
|
|
timeouted = false
|
|
|
|
template completeFuture(fut: untyped): untyped =
|
|
if fut.failed():
|
|
retFuture.fail(fut.error(), warn = false)
|
|
elif fut.cancelled():
|
|
retFuture.cancelAndSchedule()
|
|
else:
|
|
when type(fut).T is void:
|
|
retFuture.complete()
|
|
else:
|
|
retFuture.complete(fut.value)
|
|
|
|
proc continuation(udata: pointer) {.raises: [].} =
|
|
if not(retFuture.finished()):
|
|
if timeouted:
|
|
retFuture.fail(newException(AsyncTimeoutError, "Timeout exceeded!"))
|
|
return
|
|
if not(fut.finished()):
|
|
# Timer exceeded first.
|
|
timeouted = true
|
|
fut.cancelSoon()
|
|
else:
|
|
# Future `fut` completed/failed/cancelled first.
|
|
if not(isNil(timer)):
|
|
clearTimer(timer)
|
|
fut.completeFuture()
|
|
|
|
var cancellation: proc(udata: pointer) {.gcsafe, raises: [].}
|
|
cancellation = proc(udata: pointer) {.gcsafe, raises: [].} =
|
|
if not(fut.finished()):
|
|
if not(isNil(timer)):
|
|
clearTimer(timer)
|
|
fut.cancelSoon()
|
|
else:
|
|
fut.completeFuture()
|
|
|
|
if fut.finished():
|
|
fut.completeFuture()
|
|
else:
|
|
if timeout.isZero():
|
|
retFuture.fail(newException(AsyncTimeoutError, "Timeout exceeded!"))
|
|
elif timeout.isInfinite():
|
|
retFuture.cancelCallback = cancellation
|
|
fut.addCallback(continuation)
|
|
else:
|
|
moment = Moment.fromNow(timeout)
|
|
retFuture.cancelCallback = cancellation
|
|
timer = setTimer(moment, continuation, nil)
|
|
fut.addCallback(continuation)
|
|
|
|
retFuture
|
|
|
|
proc wait*[T](fut: Future[T], timeout = InfiniteDuration): Future[T] =
|
|
## Returns a future which will complete once future ``fut`` completes
|
|
## or if timeout of ``timeout`` milliseconds has been expired.
|
|
##
|
|
## If ``timeout`` is ``-1``, then statement ``await wait(fut)`` is
|
|
## equal to ``await fut``.
|
|
##
|
|
## TODO: In case when ``fut`` got cancelled, what result Future[T]
|
|
## should return, because it can't be cancelled too.
|
|
var
|
|
retFuture = newFuture[T]("chronos.wait()", {FutureFlag.OwnCancelSchedule})
|
|
|
|
waitImpl(fut, retFuture, timeout)
|
|
|
|
proc wait*[T](fut: Future[T], timeout = -1): Future[T] {.
|
|
inline, deprecated: "Use wait(Future[T], Duration)".} =
|
|
if timeout == -1:
|
|
wait(fut, InfiniteDuration)
|
|
elif timeout == 0:
|
|
wait(fut, ZeroDuration)
|
|
else:
|
|
wait(fut, timeout.milliseconds())
|
|
|
|
when defined(windows):
|
|
import ../osdefs
|
|
|
|
proc waitForSingleObject*(handle: HANDLE,
|
|
timeout: Duration): Future[WaitableResult] {.
|
|
raises: [].} =
|
|
## Waits until the specified object is in the signaled state or the
|
|
## time-out interval elapses. WaitForSingleObject() for asynchronous world.
|
|
let flags = WT_EXECUTEONLYONCE
|
|
|
|
var
|
|
retFuture = newFuture[WaitableResult]("chronos.waitForSingleObject()")
|
|
waitHandle: WaitableHandle = nil
|
|
|
|
proc continuation(udata: pointer) {.gcsafe.} =
|
|
doAssert(not(isNil(waitHandle)))
|
|
if not(retFuture.finished()):
|
|
let
|
|
ovl = cast[PtrCustomOverlapped](udata)
|
|
returnFlag = WINBOOL(ovl.data.bytesCount)
|
|
res = closeWaitable(waitHandle)
|
|
if res.isErr():
|
|
retFuture.fail(newException(AsyncError, osErrorMsg(res.error())))
|
|
else:
|
|
if returnFlag == TRUE:
|
|
retFuture.complete(WaitableResult.Timeout)
|
|
else:
|
|
retFuture.complete(WaitableResult.Ok)
|
|
|
|
proc cancellation(udata: pointer) {.gcsafe.} =
|
|
doAssert(not(isNil(waitHandle)))
|
|
if not(retFuture.finished()):
|
|
discard closeWaitable(waitHandle)
|
|
|
|
let wres = uint32(waitForSingleObject(handle, DWORD(0)))
|
|
if wres == WAIT_OBJECT_0:
|
|
retFuture.complete(WaitableResult.Ok)
|
|
return retFuture
|
|
elif wres == WAIT_ABANDONED:
|
|
retFuture.fail(newException(AsyncError, "Handle was abandoned"))
|
|
return retFuture
|
|
elif wres == WAIT_FAILED:
|
|
retFuture.fail(newException(AsyncError, osErrorMsg(osLastError())))
|
|
return retFuture
|
|
|
|
if timeout == ZeroDuration:
|
|
retFuture.complete(WaitableResult.Timeout)
|
|
return retFuture
|
|
|
|
waitHandle =
|
|
block:
|
|
let res = registerWaitable(handle, flags, timeout, continuation, nil)
|
|
if res.isErr():
|
|
retFuture.fail(newException(AsyncError, osErrorMsg(res.error())))
|
|
return retFuture
|
|
res.get()
|
|
|
|
retFuture.cancelCallback = cancellation
|
|
return retFuture
|
|
|
|
{.pop.} # Automatically deduced raises from here onwards
|
|
|
|
proc readFinished[T: not void; E](fut: InternalRaisesFuture[T, E]): lent T =
|
|
internalRaiseIfError(fut, E, fut)
|
|
fut.internalValue
|
|
|
|
proc read*[T: not void, E](fut: InternalRaisesFuture[T, E]): lent T = # {.raises: [E, FuturePendingError].}
|
|
## Retrieves the value of `fut`.
|
|
##
|
|
## If the future failed or was cancelled, the corresponding exception will be
|
|
## raised.
|
|
##
|
|
## If the future is still pending, `FuturePendingError` will be raised.
|
|
if not fut.finished():
|
|
raiseFuturePendingError(fut)
|
|
|
|
fut.readFinished()
|
|
|
|
proc read*[E](fut: InternalRaisesFuture[void, E]) = # {.raises: [E].}
|
|
## Checks that `fut` completed.
|
|
##
|
|
## If the future failed or was cancelled, the corresponding exception will be
|
|
## raised.
|
|
##
|
|
## If the future is still pending, `FuturePendingError` will be raised.
|
|
if not fut.finished():
|
|
raiseFuturePendingError(fut)
|
|
|
|
internalRaiseIfError(fut, E, fut)
|
|
|
|
proc waitFor*[T: not void; E](fut: InternalRaisesFuture[T, E]): lent T = # {.raises: [E]}
|
|
## Blocks the current thread of execution until `fut` has finished, returning
|
|
## its value.
|
|
##
|
|
## If the future failed or was cancelled, the corresponding exception will be
|
|
## raised.
|
|
##
|
|
## Must not be called recursively (from inside `async` procedures).
|
|
##
|
|
## See also `await`, `Future.read`
|
|
pollFor(fut).readFinished()
|
|
|
|
proc waitFor*[E](fut: InternalRaisesFuture[void, E]) = # {.raises: [E]}
|
|
## Blocks the current thread of execution until `fut` has finished.
|
|
##
|
|
## If the future failed or was cancelled, the corresponding exception will be
|
|
## raised.
|
|
##
|
|
## Must not be called recursively (from inside `async` procedures).
|
|
##
|
|
## See also `await`, `Future.read`
|
|
pollFor(fut).internalRaiseIfError(E, fut)
|
|
|
|
proc `or`*[T, Y, E1, E2](
|
|
fut1: InternalRaisesFuture[T, E1],
|
|
fut2: InternalRaisesFuture[Y, E2]): auto =
|
|
type
|
|
InternalRaisesFutureRaises = union(E1, E2)
|
|
|
|
let
|
|
retFuture = newFuture[void]("chronos.wait()", {FutureFlag.OwnCancelSchedule})
|
|
orImpl(fut1, fut2)
|
|
|
|
proc wait*(fut: InternalRaisesFuture, timeout = InfiniteDuration): auto =
|
|
type
|
|
T = type(fut).T
|
|
E = type(fut).E
|
|
InternalRaisesFutureRaises = E.prepend(CancelledError, AsyncTimeoutError)
|
|
|
|
let
|
|
retFuture = newFuture[T]("chronos.wait()", {FutureFlag.OwnCancelSchedule})
|
|
|
|
waitImpl(fut, retFuture, timeout)
|