321 lines
11 KiB
Nim
321 lines
11 KiB
Nim
#
|
|
#
|
|
# Nim's Runtime Library
|
|
# (c) Copyright 2015 Dominik Picheta
|
|
#
|
|
# See the file "copying.txt", included in this
|
|
# distribution, for details about the copyright.
|
|
#
|
|
|
|
import std/[macros]
|
|
|
|
# `quote do` will ruin line numbers so we avoid it using these helpers
|
|
proc completeWithResult(fut, baseType: NimNode): NimNode {.compileTime.} =
|
|
# when `baseType` is void:
|
|
# complete(`fut`)
|
|
# else:
|
|
# complete(`fut`, result)
|
|
if baseType.eqIdent("void"):
|
|
# Shortcut if we know baseType at macro expansion time
|
|
newCall(ident "complete", fut)
|
|
else:
|
|
# `baseType` might be generic and resolve to `void`
|
|
nnkWhenStmt.newTree(
|
|
nnkElifExpr.newTree(
|
|
nnkInfix.newTree(ident "is", baseType, ident "void"),
|
|
newCall(ident "complete", fut)
|
|
),
|
|
nnkElseExpr.newTree(
|
|
newCall(ident "complete", fut, ident "result")
|
|
)
|
|
)
|
|
|
|
proc completeWithNode(fut, baseType, node: NimNode): NimNode {.compileTime.} =
|
|
# when typeof(`node`) is void:
|
|
# `node` # statement / explicit return
|
|
# -> completeWithResult(fut, baseType)
|
|
# else: # expression / implicit return
|
|
# complete(`fut`, `node`)
|
|
if node.kind == nnkEmpty: # shortcut when known at macro expanstion time
|
|
completeWithResult(fut, baseType)
|
|
else:
|
|
# Handle both expressions and statements - since the type is not know at
|
|
# macro expansion time, we delegate this choice to a later compilation stage
|
|
# with `when`.
|
|
nnkWhenStmt.newTree(
|
|
nnkElifExpr.newTree(
|
|
nnkInfix.newTree(
|
|
ident "is", nnkTypeOfExpr.newTree(node), ident "void"),
|
|
newStmtList(
|
|
node,
|
|
completeWithResult(fut, baseType)
|
|
)
|
|
),
|
|
nnkElseExpr.newTree(
|
|
newCall(ident "complete", fut, node)
|
|
)
|
|
)
|
|
|
|
proc processBody(node, fut, baseType: NimNode): NimNode {.compileTime.} =
|
|
#echo(node.treeRepr)
|
|
case node.kind
|
|
of nnkReturnStmt:
|
|
let
|
|
res = newNimNode(nnkStmtList, node)
|
|
res.add completeWithNode(fut, baseType, processBody(node[0], fut, baseType))
|
|
res.add newNimNode(nnkReturnStmt, node).add(newNilLit())
|
|
|
|
res
|
|
of RoutineNodes-{nnkTemplateDef}:
|
|
# skip all the nested procedure definitions
|
|
node
|
|
else:
|
|
for i in 0 ..< node.len:
|
|
# We must not transform nested procedures of any form, otherwise
|
|
# `fut` will be used for all nested procedures as their own
|
|
# `retFuture`.
|
|
node[i] = processBody(node[i], fut, baseType)
|
|
node
|
|
|
|
proc getName(node: NimNode): string {.compileTime.} =
|
|
case node.kind
|
|
of nnkSym:
|
|
return node.strVal
|
|
of nnkPostfix:
|
|
return node[1].strVal
|
|
of nnkIdent:
|
|
return node.strVal
|
|
of nnkEmpty:
|
|
return "anonymous"
|
|
else:
|
|
error("Unknown name.")
|
|
|
|
macro unsupported(s: static[string]): untyped =
|
|
error s
|
|
|
|
proc params2(someProc: NimNode): NimNode =
|
|
# until https://github.com/nim-lang/Nim/pull/19563 is available
|
|
if someProc.kind == nnkProcTy:
|
|
someProc[0]
|
|
else:
|
|
params(someProc)
|
|
|
|
proc cleanupOpenSymChoice(node: NimNode): NimNode {.compileTime.} =
|
|
# Replace every Call -> OpenSymChoice by a Bracket expr
|
|
# ref https://github.com/nim-lang/Nim/issues/11091
|
|
if node.kind in nnkCallKinds and
|
|
node[0].kind == nnkOpenSymChoice and node[0].eqIdent("[]"):
|
|
result = newNimNode(nnkBracketExpr)
|
|
for child in node[1..^1]:
|
|
result.add(cleanupOpenSymChoice(child))
|
|
else:
|
|
result = node.copyNimNode()
|
|
for child in node:
|
|
result.add(cleanupOpenSymChoice(child))
|
|
|
|
proc asyncSingleProc(prc: NimNode): NimNode {.compileTime.} =
|
|
## This macro transforms a single procedure into a closure iterator.
|
|
## The ``async`` macro supports a stmtList holding multiple async procedures.
|
|
if prc.kind notin {nnkProcTy, nnkProcDef, nnkLambda, nnkMethodDef, nnkDo}:
|
|
error("Cannot transform " & $prc.kind & " into an async proc." &
|
|
" proc/method definition or lambda node expected.", prc)
|
|
|
|
let returnType = cleanupOpenSymChoice(prc.params2[0])
|
|
|
|
# Verify that the return type is a Future[T]
|
|
let baseType =
|
|
if returnType.kind == nnkEmpty:
|
|
ident "void"
|
|
elif not (
|
|
returnType.kind == nnkBracketExpr and eqIdent(returnType[0], "Future")):
|
|
error(
|
|
"Expected return type of 'Future' got '" & repr(returnType) & "'", prc)
|
|
return
|
|
else:
|
|
returnType[1]
|
|
|
|
let
|
|
baseTypeIsVoid = baseType.eqIdent("void")
|
|
futureVoidType = nnkBracketExpr.newTree(ident "Future", ident "void")
|
|
|
|
if prc.kind in {nnkProcDef, nnkLambda, nnkMethodDef, nnkDo}:
|
|
let
|
|
prcName = prc.name.getName
|
|
outerProcBody = newNimNode(nnkStmtList, prc.body)
|
|
|
|
# Copy comment for nimdoc
|
|
if prc.body.len > 0 and prc.body[0].kind == nnkCommentStmt:
|
|
outerProcBody.add(prc.body[0])
|
|
|
|
let
|
|
internalFutureSym = ident "chronosInternalRetFuture"
|
|
internalFutureType =
|
|
if baseTypeIsVoid: futureVoidType
|
|
else: returnType
|
|
castFutureSym = nnkCast.newTree(internalFutureType, internalFutureSym)
|
|
|
|
procBody = prc.body.processBody(castFutureSym, baseType)
|
|
|
|
# don't do anything with forward bodies (empty)
|
|
if procBody.kind != nnkEmpty:
|
|
let
|
|
# fix #13899, `defer` should not escape its original scope
|
|
procBodyBlck = nnkBlockStmt.newTree(newEmptyNode(), procBody)
|
|
|
|
resultDecl = nnkWhenStmt.newTree(
|
|
# when `baseType` is void:
|
|
nnkElifExpr.newTree(
|
|
nnkInfix.newTree(ident "is", baseType, ident "void"),
|
|
quote do:
|
|
template result: auto {.used.} =
|
|
{.fatal: "You should not reference the `result` variable inside" &
|
|
" a void async proc".}
|
|
),
|
|
# else:
|
|
nnkElseExpr.newTree(
|
|
newStmtList(
|
|
quote do: {.push warning[resultshadowed]: off.},
|
|
# var result: `baseType`
|
|
nnkVarSection.newTree(
|
|
nnkIdentDefs.newTree(ident "result", baseType, newEmptyNode())),
|
|
quote do: {.pop.},
|
|
)
|
|
)
|
|
)
|
|
|
|
completeDecl = completeWithNode(castFutureSym, baseType, procBodyBlck)
|
|
|
|
closureBody = newStmtList(resultDecl, completeDecl)
|
|
|
|
internalFutureParameter = nnkIdentDefs.newTree(
|
|
internalFutureSym, newIdentNode("FutureBase"), newEmptyNode())
|
|
iteratorNameSym = genSym(nskIterator, $prcName)
|
|
closureIterator = newProc(
|
|
iteratorNameSym,
|
|
[newIdentNode("FutureBase"), internalFutureParameter],
|
|
closureBody, nnkIteratorDef)
|
|
|
|
iteratorNameSym.copyLineInfo(prc)
|
|
|
|
closureIterator.pragma = newNimNode(nnkPragma, lineInfoFrom=prc.body)
|
|
closureIterator.addPragma(newIdentNode("closure"))
|
|
|
|
# `async` code must be gcsafe
|
|
closureIterator.addPragma(newIdentNode("gcsafe"))
|
|
|
|
# TODO when push raises is active in a module, the iterator here inherits
|
|
# that annotation - here we explicitly disable it again which goes
|
|
# against the spirit of the raises annotation - one should investigate
|
|
# here the possibility of transporting more specific error types here
|
|
# for example by casting exceptions coming out of `await`..
|
|
let raises = nnkBracket.newTree()
|
|
when chronosStrictException:
|
|
raises.add(newIdentNode("CatchableError"))
|
|
else:
|
|
raises.add(newIdentNode("Exception"))
|
|
|
|
closureIterator.addPragma(nnkExprColonExpr.newTree(
|
|
newIdentNode("raises"),
|
|
raises
|
|
))
|
|
|
|
# If proc has an explicit gcsafe pragma, we add it to iterator as well.
|
|
# TODO if these lines are not here, srcloc tests fail (!)
|
|
if prc.pragma.findChild(it.kind in {nnkSym, nnkIdent} and
|
|
it.strVal == "gcsafe") != nil:
|
|
closureIterator.addPragma(newIdentNode("gcsafe"))
|
|
|
|
outerProcBody.add(closureIterator)
|
|
|
|
# -> let resultFuture = newFuture[T]()
|
|
# declared at the end to be sure that the closure
|
|
# doesn't reference it, avoid cyclic ref (#203)
|
|
let
|
|
retFutureSym = ident "resultFuture"
|
|
retFutureSym.copyLineInfo(prc)
|
|
# Do not change this code to `quote do` version because `instantiationInfo`
|
|
# will be broken for `newFuture()` call.
|
|
outerProcBody.add(
|
|
newLetStmt(
|
|
retFutureSym,
|
|
newCall(newTree(nnkBracketExpr, ident "newFuture", baseType),
|
|
newLit(prcName))
|
|
)
|
|
)
|
|
# -> resultFuture.internalClosure = iterator
|
|
outerProcBody.add(
|
|
newAssignment(
|
|
newDotExpr(retFutureSym, newIdentNode("internalClosure")),
|
|
iteratorNameSym)
|
|
)
|
|
|
|
# -> futureContinue(resultFuture))
|
|
outerProcBody.add(
|
|
newCall(newIdentNode("futureContinue"), retFutureSym)
|
|
)
|
|
|
|
# -> return resultFuture
|
|
outerProcBody.add newNimNode(nnkReturnStmt, prc.body[^1]).add(retFutureSym)
|
|
|
|
prc.body = outerProcBody
|
|
|
|
if prc.kind notin {nnkProcTy, nnkLambda}: # TODO: Nim bug?
|
|
prc.addPragma(newColonExpr(ident "stackTrace", ident "off"))
|
|
|
|
# See **Remark 435** in this file.
|
|
# https://github.com/nim-lang/RFCs/issues/435
|
|
prc.addPragma(newIdentNode("gcsafe"))
|
|
|
|
prc.addPragma(nnkExprColonExpr.newTree(
|
|
newIdentNode("raises"),
|
|
nnkBracket.newTree()
|
|
))
|
|
|
|
if baseTypeIsVoid:
|
|
if returnType.kind == nnkEmpty:
|
|
# Add Future[void]
|
|
prc.params2[0] = futureVoidType
|
|
|
|
prc
|
|
|
|
template await*[T](f: Future[T]): untyped =
|
|
when declared(chronosInternalRetFuture):
|
|
chronosInternalRetFuture.internalChild = f
|
|
# `futureContinue` calls the iterator generated by the `async`
|
|
# transformation - `yield` gives control back to `futureContinue` which is
|
|
# responsible for resuming execution once the yielded future is finished
|
|
yield chronosInternalRetFuture.internalChild
|
|
|
|
# `child` is guaranteed to have been `finished` after the yield
|
|
if chronosInternalRetFuture.internalMustCancel:
|
|
raise newCancelledError()
|
|
|
|
# `child` released by `futureContinue`
|
|
chronosInternalRetFuture.internalChild.internalCheckComplete()
|
|
when T isnot void:
|
|
cast[type(f)](chronosInternalRetFuture.internalChild).internalRead()
|
|
else:
|
|
unsupported "await is only available within {.async.}"
|
|
|
|
template awaitne*[T](f: Future[T]): Future[T] =
|
|
when declared(chronosInternalRetFuture):
|
|
chronosInternalRetFuture.internalChild = f
|
|
yield chronosInternalRetFuture.internalChild
|
|
if chronosInternalRetFuture.internalMustCancel:
|
|
raise newCancelledError()
|
|
cast[type(f)](chronosInternalRetFuture.internalChild)
|
|
else:
|
|
unsupported "awaitne is only available within {.async.}"
|
|
|
|
macro async*(prc: untyped): untyped =
|
|
## Macro which processes async procedures into the appropriate
|
|
## iterators and yield statements.
|
|
if prc.kind == nnkStmtList:
|
|
result = newStmtList()
|
|
for oneProc in prc:
|
|
result.add asyncSingleProc(oneProc)
|
|
else:
|
|
result = asyncSingleProc(prc)
|
|
when chronosDumpAsync:
|
|
echo repr result
|