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Diffstat (limited to 'js/src/vm/AsyncIteration.cpp')
| -rw-r--r-- | js/src/vm/AsyncIteration.cpp | 564 |
1 files changed, 564 insertions, 0 deletions
diff --git a/js/src/vm/AsyncIteration.cpp b/js/src/vm/AsyncIteration.cpp new file mode 100644 index 000000000..04effe1b1 --- /dev/null +++ b/js/src/vm/AsyncIteration.cpp @@ -0,0 +1,564 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- + * vim: set ts=8 sts=4 et sw=4 tw=99: + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#include "vm/AsyncIteration.h" + +#include "jsarray.h" +#include "jscompartment.h" + +#include "builtin/Promise.h" +#include "vm/GeneratorObject.h" +#include "vm/GlobalObject.h" +#include "vm/Interpreter.h" +#include "vm/SelfHosting.h" + +#include "jscntxtinlines.h" +#include "jsobjinlines.h" + +#include "vm/NativeObject-inl.h" + +using namespace js; +using namespace js::gc; + +#define UNWRAPPED_ASYNC_WRAPPED_SLOT 1 +#define WRAPPED_ASYNC_UNWRAPPED_SLOT 0 + +// Async Iteration proposal 2.3.10 Runtime Semantics: EvaluateBody. +static bool +WrappedAsyncGenerator(JSContext* cx, unsigned argc, Value* vp) +{ + CallArgs args = CallArgsFromVp(argc, vp); + + RootedFunction wrapped(cx, &args.callee().as<JSFunction>()); + RootedValue unwrappedVal(cx, wrapped->getExtendedSlot(WRAPPED_ASYNC_UNWRAPPED_SLOT)); + RootedFunction unwrapped(cx, &unwrappedVal.toObject().as<JSFunction>()); + RootedValue thisValue(cx, args.thisv()); + + // Step 1. + RootedValue generatorVal(cx); + InvokeArgs args2(cx); + if (!args2.init(cx, argc)) + return false; + for (size_t i = 0, len = argc; i < len; i++) + args2[i].set(args[i]); + if (!Call(cx, unwrappedVal, thisValue, args2, &generatorVal)) + return false; + + // Step 2. + Rooted<AsyncGeneratorObject*> asyncGenObj( + cx, AsyncGeneratorObject::create(cx, wrapped, generatorVal)); + if (!asyncGenObj) + return false; + + // Step 3 (skipped). + // Done in AsyncGeneratorObject::create and generator. + + // Step 4. + args.rval().setObject(*asyncGenObj); + return true; +} + +JSObject* +js::WrapAsyncGeneratorWithProto(JSContext* cx, HandleFunction unwrapped, HandleObject proto) +{ + MOZ_ASSERT(unwrapped->isAsync()); + MOZ_ASSERT(proto, "We need an explicit prototype to avoid the default" + "%FunctionPrototype% fallback in NewFunctionWithProto()."); + + // Create a new function with AsyncGeneratorPrototype, reusing the name and + // the length of `unwrapped`. + + RootedAtom funName(cx, unwrapped->explicitName()); + uint16_t length; + if (!JSFunction::getLength(cx, unwrapped, &length)) + return nullptr; + + RootedFunction wrapped(cx, NewFunctionWithProto(cx, WrappedAsyncGenerator, length, + JSFunction::NATIVE_FUN, nullptr, + funName, proto, + AllocKind::FUNCTION_EXTENDED, + TenuredObject)); + if (!wrapped) + return nullptr; + + if (unwrapped->hasCompileTimeName()) + wrapped->setCompileTimeName(unwrapped->compileTimeName()); + + // Link them to each other to make GetWrappedAsyncGenerator and + // GetUnwrappedAsyncGenerator work. + unwrapped->setExtendedSlot(UNWRAPPED_ASYNC_WRAPPED_SLOT, ObjectValue(*wrapped)); + wrapped->setExtendedSlot(WRAPPED_ASYNC_UNWRAPPED_SLOT, ObjectValue(*unwrapped)); + + return wrapped; +} + +JSObject* +js::WrapAsyncGenerator(JSContext* cx, HandleFunction unwrapped) +{ + RootedObject proto(cx, GlobalObject::getOrCreateAsyncGenerator(cx, cx->global())); + if (!proto) + return nullptr; + + return WrapAsyncGeneratorWithProto(cx, unwrapped, proto); +} + +bool +js::IsWrappedAsyncGenerator(JSFunction* fun) +{ + return fun->maybeNative() == WrappedAsyncGenerator; +} + +JSFunction* +js::GetWrappedAsyncGenerator(JSFunction* unwrapped) +{ + MOZ_ASSERT(unwrapped->isAsync()); + return &unwrapped->getExtendedSlot(UNWRAPPED_ASYNC_WRAPPED_SLOT).toObject().as<JSFunction>(); +} + +JSFunction* +js::GetUnwrappedAsyncGenerator(JSFunction* wrapped) +{ + MOZ_ASSERT(IsWrappedAsyncGenerator(wrapped)); + JSFunction* unwrapped = &wrapped->getExtendedSlot(WRAPPED_ASYNC_UNWRAPPED_SLOT) + .toObject().as<JSFunction>(); + MOZ_ASSERT(unwrapped->isAsync()); + return unwrapped; +} + +static MOZ_MUST_USE bool +AsyncGeneratorResume(JSContext* cx, Handle<AsyncGeneratorObject*> asyncGenObj, + CompletionKind completionKind, HandleValue argument); + +// Async Iteration proposal 5.1.1 Await Fulfilled Functions. +MOZ_MUST_USE bool +js::AsyncGeneratorAwaitedFulfilled(JSContext* cx, Handle<AsyncGeneratorObject*> asyncGenObj, + HandleValue value) +{ + return AsyncGeneratorResume(cx, asyncGenObj, CompletionKind::Normal, value); +} + +// Async Iteration proposal 5.1.2 Await Rejected Functions. +MOZ_MUST_USE bool +js::AsyncGeneratorAwaitedRejected(JSContext* cx, Handle<AsyncGeneratorObject*> asyncGenObj, + HandleValue reason) +{ + return AsyncGeneratorResume(cx, asyncGenObj, CompletionKind::Throw, reason); +} + +// Async Iteration proposal 6.4.1.2 AsyncGenerator.prototype.next. +static bool +AsyncGeneratorNext(JSContext* cx, unsigned argc, Value* vp) +{ + CallArgs args = CallArgsFromVp(argc, vp); + + // Steps 1-3. + return AsyncGeneratorEnqueue(cx, args.thisv(), CompletionKind::Normal, args.get(0), + args.rval()); +} + +// Async Iteration proposal 6.4.1.3 AsyncGenerator.prototype.return. +static bool +AsyncGeneratorReturn(JSContext* cx, unsigned argc, Value* vp) +{ + CallArgs args = CallArgsFromVp(argc, vp); + + // Steps 1-3. + return AsyncGeneratorEnqueue(cx, args.thisv(), CompletionKind::Return, args.get(0), + args.rval()); +} + +// Async Iteration proposal 6.4.1.4 AsyncGenerator.prototype.throw. +static bool +AsyncGeneratorThrow(JSContext* cx, unsigned argc, Value* vp) +{ + CallArgs args = CallArgsFromVp(argc, vp); + + // Steps 1-3. + return AsyncGeneratorEnqueue(cx, args.thisv(), CompletionKind::Throw, args.get(0), + args.rval()); +} + +const Class AsyncGeneratorObject::class_ = { + "AsyncGenerator", + JSCLASS_HAS_RESERVED_SLOTS(AsyncGeneratorObject::Slots) +}; + +// ES 2017 draft 9.1.13. +template <typename ProtoGetter> +static JSObject* +OrdinaryCreateFromConstructor(JSContext* cx, HandleFunction fun, + ProtoGetter protoGetter, const Class* clasp) +{ + // Step 1 (skipped). + + // Step 2. + RootedValue protoVal(cx); + if (!GetProperty(cx, fun, fun, cx->names().prototype, &protoVal)) + return nullptr; + + RootedObject proto(cx, protoVal.isObject() ? &protoVal.toObject() : nullptr); + if (!proto) { + proto = protoGetter(cx, cx->global()); + if (!proto) + return nullptr; + } + + // Step 3. + return NewNativeObjectWithGivenProto(cx, clasp, proto); +} + +/* static */ AsyncGeneratorObject* +AsyncGeneratorObject::create(JSContext* cx, HandleFunction asyncGen, HandleValue generatorVal) +{ + MOZ_ASSERT(generatorVal.isObject()); + MOZ_ASSERT(generatorVal.toObject().is<GeneratorObject>()); + + RootedObject obj( + cx, OrdinaryCreateFromConstructor(cx, asyncGen, + GlobalObject::getOrCreateAsyncGeneratorPrototype, + &class_)); + if (!obj) + return nullptr; + + Handle<AsyncGeneratorObject*> asyncGenObj = obj.as<AsyncGeneratorObject>(); + + // Async Iteration proposal 6.4.3.2 AsyncGeneratorStart. + // Step 6. + asyncGenObj->setGenerator(generatorVal); + + // Step 7. + asyncGenObj->setSuspendedStart(); + + // Step 8. + asyncGenObj->clearSingleQueueRequest(); + + return asyncGenObj; +} + +/* static */ MOZ_MUST_USE bool +AsyncGeneratorObject::enqueueRequest(JSContext* cx, Handle<AsyncGeneratorObject*> asyncGenObj, + Handle<AsyncGeneratorRequest*> request) +{ + if (asyncGenObj->isSingleQueue()) { + if (asyncGenObj->isSingleQueueEmpty()) { + asyncGenObj->setSingleQueueRequest(request); + return true; + } + + RootedArrayObject queue(cx, NewDenseEmptyArray(cx)); + if (!queue) + return false; + + if (!NewbornArrayPush(cx, queue, ObjectValue(*asyncGenObj->singleQueueRequest()))) + return false; + if (!NewbornArrayPush(cx, queue, ObjectValue(*request))) + return false; + + asyncGenObj->setQueue(queue); + return true; + } + + RootedArrayObject queue(cx, asyncGenObj->queue()); + + FixedInvokeArgs<1> args(cx); + args[0].setObject(*request); + args.setThis(ObjectValue(*queue)); + return CallJSNative(cx, array_push, args); +} + +/* static */ AsyncGeneratorRequest* +AsyncGeneratorObject::dequeueRequest(JSContext* cx, Handle<AsyncGeneratorObject*> asyncGenObj) +{ + if (asyncGenObj->isSingleQueue()) { + AsyncGeneratorRequest* request = asyncGenObj->singleQueueRequest(); + asyncGenObj->clearSingleQueueRequest(); + return request; + } + + RootedArrayObject queue(cx, asyncGenObj->queue()); + + FixedInvokeArgs<0> args(cx); + args.setThis(ObjectValue(*queue)); + if (!CallJSNative(cx, array_shift, args)) + return nullptr; + + return &args.rval().toObject().as<AsyncGeneratorRequest>(); +} + +/* static */ AsyncGeneratorRequest* +AsyncGeneratorObject::peekRequest(JSContext* cx, Handle<AsyncGeneratorObject*> asyncGenObj) +{ + if (asyncGenObj->isSingleQueue()) + return asyncGenObj->singleQueueRequest(); + + RootedArrayObject queue(cx, asyncGenObj->queue()); + + RootedValue requestVal(cx); + if (!GetElement(cx, queue, queue, 0, &requestVal)) + return nullptr; + + return &requestVal.toObject().as<AsyncGeneratorRequest>(); +} + +const Class AsyncGeneratorRequest::class_ = { + "AsyncGeneratorRequest", + JSCLASS_HAS_RESERVED_SLOTS(AsyncGeneratorRequest::Slots) +}; + +// Async Iteration proposal 6.4.3.1. +/* static */ AsyncGeneratorRequest* +AsyncGeneratorRequest::create(JSContext* cx, CompletionKind completionKind_, + HandleValue completionValue_, HandleObject promise_) +{ + RootedObject obj(cx, NewNativeObjectWithGivenProto(cx, &class_, nullptr)); + if (!obj) + return nullptr; + + Handle<AsyncGeneratorRequest*> request = obj.as<AsyncGeneratorRequest>(); + request->setCompletionKind(completionKind_); + request->setCompletionValue(completionValue_); + request->setPromise(promise_); + return request; +} + +// Async Iteration proposal 6.4.3.2 steps 5.d-g. +static MOZ_MUST_USE bool +AsyncGeneratorReturned(JSContext* cx, Handle<AsyncGeneratorObject*> asyncGenObj, + HandleValue value) +{ + // Step 5.d. + asyncGenObj->setCompleted(); + + // Step 5.e (done in bytecode). + // Step 5.f.i (implicit). + + // Step 5.g. + return AsyncGeneratorResolve(cx, asyncGenObj, value, true); +} + +// Async Iteration proposal 6.4.3.2 steps 5.d, f. +static MOZ_MUST_USE bool +AsyncGeneratorThrown(JSContext* cx, Handle<AsyncGeneratorObject*> asyncGenObj) +{ + // Step 5.d. + asyncGenObj->setCompleted(); + + // Not much we can do about uncatchable exceptions, so just bail. + if (!cx->isExceptionPending()) + return false; + + // Step 5.f.i. + RootedValue value(cx); + if (!GetAndClearException(cx, &value)) + return false; + + // Step 5.f.ii. + return AsyncGeneratorReject(cx, asyncGenObj, value); +} + +// Async Iteration proposal 6.4.3.5. +MOZ_MUST_USE bool +js::AsyncGeneratorResumeNext(JSContext* cx, Handle<AsyncGeneratorObject*> asyncGenObj) +{ + // Step 1 (implicit). + + // Steps 2-3. + MOZ_ASSERT(!asyncGenObj->isExecuting()); + + // Steps 4-5. + if (asyncGenObj->isQueueEmpty()) + return true; + + // Steps 6-7. + Rooted<AsyncGeneratorRequest*> request( + cx, AsyncGeneratorObject::peekRequest(cx, asyncGenObj)); + if (!request) + return false; + + // Step 8. + CompletionKind completionKind = request->completionKind(); + + // Step 9. + if (completionKind != CompletionKind::Normal) { + // Step 9.a. + if (asyncGenObj->isSuspendedStart()) + asyncGenObj->setCompleted(); + + // Step 9.b. + if (asyncGenObj->isCompleted()) { + // Step 9.b.i. + RootedValue value(cx, request->completionValue()); + if (completionKind == CompletionKind::Return) + return AsyncGeneratorResolve(cx, asyncGenObj, value, true); + // Step 9.b.ii. + return AsyncGeneratorReject(cx, asyncGenObj, value); + } + } else if (asyncGenObj->isCompleted()) { + // Step 10. + return AsyncGeneratorResolve(cx, asyncGenObj, UndefinedHandleValue, true); + } + + // Step 11. + MOZ_ASSERT(asyncGenObj->isSuspendedStart() || asyncGenObj->isSuspendedYield()); + + // Step 15 (reordered). + asyncGenObj->setExecuting(); + + RootedValue argument(cx, request->completionValue()); + + // Steps 12-14, 16-20. + return AsyncGeneratorResume(cx, asyncGenObj, completionKind, argument); +} + +// Async Iteration proposal 6.2.1.2 (partially). +// Most steps are done in generator. +static MOZ_MUST_USE bool +AsyncGeneratorYield(JSContext* cx, Handle<AsyncGeneratorObject*> asyncGenObj, + HandleValue value, bool done) +{ + // Step 6. + asyncGenObj->setSuspendedYield(); + + // Step 10.c. + return AsyncGeneratorResolve(cx, asyncGenObj, value, done); +} + +// Async Iteration proposal 6.4.3.5 steps 12-14, 16-20. +// Async Iteration proposal 6.2.1.2 step 10. +// Async Iteration proposal 6.4.3.2 step 5.f-g. +// Async Iteration proposal 5.1 steps 2-9. +// Execution context switching is handled in generator. +static MOZ_MUST_USE bool +AsyncGeneratorResume(JSContext* cx, Handle<AsyncGeneratorObject*> asyncGenObj, + CompletionKind completionKind, HandleValue argument) +{ + RootedValue generatorVal(cx, asyncGenObj->generatorVal()); + + // 6.4.3.5 steps 12-14, 16-20. + HandlePropertyName funName = completionKind == CompletionKind::Normal + ? cx->names().StarGeneratorNext + : completionKind == CompletionKind::Throw + ? cx->names().StarGeneratorThrow + : cx->names().StarGeneratorReturn; + FixedInvokeArgs<1> args(cx); + args[0].set(argument); + RootedValue result(cx); + if (!CallSelfHostedFunction(cx, funName, generatorVal, args, &result)) { + // 6.4.3.2 step 5.d, f. + return AsyncGeneratorThrown(cx, asyncGenObj); + } + + // The following code corresponds to the following 3 cases: + // * yield + // * await + // * return + // For await and return, property access is done on an internal result + // object and it's not observable. + // For yield, it's done on an user-provided result object, and it's + // observable, so perform in that order in all cases. + + RootedObject resultObj(cx, &result.toObject()); + RootedValue value(cx); + RootedValue doneVal(cx); + + // 6.2.1.2 step 10.a. + if (!GetProperty(cx, resultObj, resultObj, cx->names().value, &value)) + return false; + + // 6.2.1.2 step 10.b. + if (!GetProperty(cx, resultObj, resultObj, cx->names().done, &doneVal)) + return false; + + // 6.2.1.2 step 10.c. + if (asyncGenObj->generatorObj()->isAfterYield()) + return AsyncGeneratorYield(cx, asyncGenObj, value, ToBoolean(doneVal)); + + // 6.4.3.2 step 5.d-g. + if (ToBoolean(doneVal)) { + MOZ_ASSERT(!asyncGenObj->generatorObj()->isAfterAwait()); + return AsyncGeneratorReturned(cx, asyncGenObj, value); + } + + MOZ_ASSERT(asyncGenObj->generatorObj()->isAfterAwait()); + + // 5.1 steps 2-9. + return AsyncGeneratorAwait(cx, asyncGenObj, value); +} + +static const JSFunctionSpec async_iterator_proto_methods[] = { + JS_SELF_HOSTED_SYM_FN(asyncIterator, "AsyncIteratorIdentity", 0, 0), + JS_FS_END +}; + +static const JSFunctionSpec async_generator_methods[] = { + JS_FN("next", AsyncGeneratorNext, 1, 0), + JS_FN("throw", AsyncGeneratorThrow, 1, 0), + JS_FN("return", AsyncGeneratorReturn, 1, 0), + JS_FS_END +}; + +/* static */ MOZ_MUST_USE bool +GlobalObject::initAsyncGenerators(JSContext* cx, Handle<GlobalObject*> global) +{ + if (global->getReservedSlot(ASYNC_ITERATOR_PROTO).isObject()) + return true; + + // Async Iteration proposal 6.1.2 %AsyncIteratorPrototype%. + RootedObject asyncIterProto(cx, GlobalObject::createBlankPrototype<PlainObject>(cx, global)); + if (!asyncIterProto) + return false; + if (!DefinePropertiesAndFunctions(cx, asyncIterProto, nullptr, async_iterator_proto_methods)) + return false; + + // Async Iteration proposal 6.4.1 %AsyncGeneratorPrototype%. + RootedObject asyncGenProto( + cx, GlobalObject::createBlankPrototypeInheriting(cx, global, &PlainObject::class_, + asyncIterProto)); + if (!asyncGenProto) + return false; + if (!DefinePropertiesAndFunctions(cx, asyncGenProto, nullptr, async_generator_methods) || + !DefineToStringTag(cx, asyncGenProto, cx->names().AsyncGenerator)) + { + return false; + } + + // Async Iteration proposal 6.3.3 %AsyncGenerator%. + RootedObject asyncGenerator(cx, NewSingletonObjectWithFunctionPrototype(cx, global)); + if (!asyncGenerator) + return false; + if (!JSObject::setDelegate(cx, asyncGenerator)) + return false; + if (!LinkConstructorAndPrototype(cx, asyncGenerator, asyncGenProto, JSPROP_READONLY, + JSPROP_READONLY) || + !DefineToStringTag(cx, asyncGenerator, cx->names().AsyncGeneratorFunction)) + { + return false; + } + + RootedValue function(cx, global->getConstructor(JSProto_Function)); + if (!function.toObjectOrNull()) + return false; + RootedObject proto(cx, &function.toObject()); + RootedAtom name(cx, cx->names().AsyncGeneratorFunction); + + // Async Iteration proposal 6.3.2 %AsyncGeneratorFunction%. + RootedObject asyncGenFunction( + cx, NewFunctionWithProto(cx, AsyncGeneratorConstructor, 1, JSFunction::NATIVE_CTOR, + nullptr, name, proto, gc::AllocKind::FUNCTION, SingletonObject)); + if (!asyncGenFunction) + return false; + if (!LinkConstructorAndPrototype(cx, asyncGenFunction, asyncGenerator, + JSPROP_PERMANENT | JSPROP_READONLY, JSPROP_READONLY)) + { + return false; + } + + global->setReservedSlot(ASYNC_ITERATOR_PROTO, ObjectValue(*asyncIterProto)); + global->setReservedSlot(ASYNC_GENERATOR, ObjectValue(*asyncGenerator)); + global->setReservedSlot(ASYNC_GENERATOR_FUNCTION, ObjectValue(*asyncGenFunction)); + global->setReservedSlot(ASYNC_GENERATOR_PROTO, ObjectValue(*asyncGenProto)); + return true; +} |