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Diffstat (limited to '')
| -rw-r--r-- | js/src/vm/AsyncIteration.cpp | 1484 |
1 files changed, 1484 insertions, 0 deletions
diff --git a/js/src/vm/AsyncIteration.cpp b/js/src/vm/AsyncIteration.cpp new file mode 100644 index 0000000000..293fc8c31c --- /dev/null +++ b/js/src/vm/AsyncIteration.cpp @@ -0,0 +1,1484 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- + * vim: set ts=8 sts=2 et sw=2 tw=80: + * 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 "builtin/Promise.h" // js::PromiseHandler, js::CreatePromiseObjectForAsyncGenerator, js::AsyncFromSyncIteratorMethod, js::ResolvePromiseInternal, js::RejectPromiseInternal, js::InternalAsyncGeneratorAwait +#include "js/friend/ErrorMessages.h" // js::GetErrorMessage, JSMSG_* +#include "js/PropertySpec.h" +#include "vm/CompletionKind.h" +#include "vm/FunctionFlags.h" // js::FunctionFlags +#include "vm/GeneratorObject.h" +#include "vm/GlobalObject.h" +#include "vm/Interpreter.h" +#include "vm/PlainObject.h" // js::PlainObject +#include "vm/PromiseObject.h" // js::PromiseObject +#include "vm/Realm.h" +#include "vm/SelfHosting.h" +#include "vm/WellKnownAtom.h" // js_*_str + +#include "vm/JSObject-inl.h" +#include "vm/List-inl.h" + +using namespace js; + +// --------------- +// Async generator +// --------------- + +const JSClass AsyncGeneratorObject::class_ = { + "AsyncGenerator", + JSCLASS_HAS_RESERVED_SLOTS(AsyncGeneratorObject::Slots), + &classOps_, +}; + +const JSClassOps AsyncGeneratorObject::classOps_ = { + nullptr, // addProperty + nullptr, // delProperty + nullptr, // enumerate + nullptr, // newEnumerate + nullptr, // resolve + nullptr, // mayResolve + nullptr, // finalize + nullptr, // call + nullptr, // construct + CallTraceMethod<AbstractGeneratorObject>, // trace +}; + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// OrdinaryCreateFromConstructor ( constructor, intrinsicDefaultProto +// [ , internalSlotsList ] ) +// https://tc39.es/ecma262/#sec-ordinarycreatefromconstructor +// +// specialized for AsyncGeneratorObjects. +static AsyncGeneratorObject* OrdinaryCreateFromConstructorAsynGen( + JSContext* cx, HandleFunction constructor) { + // Step 1: Assert... + // (implicit) + + // Step 2. Let proto be + // ? GetPrototypeFromConstructor(constructor, intrinsicDefaultProto). + RootedValue protoVal(cx); + if (!GetProperty(cx, constructor, constructor, cx->names().prototype, + &protoVal)) { + return nullptr; + } + + RootedObject proto(cx, protoVal.isObject() ? &protoVal.toObject() : nullptr); + if (!proto) { + proto = GlobalObject::getOrCreateAsyncGeneratorPrototype(cx, cx->global()); + if (!proto) { + return nullptr; + } + } + + // Step 3. Return ! OrdinaryObjectCreate(proto, internalSlotsList). + return NewObjectWithGivenProto<AsyncGeneratorObject>(cx, proto); +} + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// AsyncGeneratorStart ( generator, generatorBody ) +// https://tc39.es/ecma262/#sec-asyncgeneratorstart +// +// Steps 6-7. +/* static */ +AsyncGeneratorObject* AsyncGeneratorObject::create(JSContext* cx, + HandleFunction asyncGen) { + MOZ_ASSERT(asyncGen->isAsync() && asyncGen->isGenerator()); + + AsyncGeneratorObject* generator = + OrdinaryCreateFromConstructorAsynGen(cx, asyncGen); + if (!generator) { + return nullptr; + } + + // Step 6. Set generator.[[AsyncGeneratorState]] to suspendedStart. + generator->setSuspendedStart(); + + // Step 7. Set generator.[[AsyncGeneratorQueue]] to a new empty List. + generator->clearSingleQueueRequest(); + + generator->clearCachedRequest(); + + return generator; +} + +/* static */ +AsyncGeneratorRequest* AsyncGeneratorObject::createRequest( + JSContext* cx, Handle<AsyncGeneratorObject*> generator, + CompletionKind completionKind, HandleValue completionValue, + Handle<PromiseObject*> promise) { + if (!generator->hasCachedRequest()) { + return AsyncGeneratorRequest::create(cx, completionKind, completionValue, + promise); + } + + AsyncGeneratorRequest* request = generator->takeCachedRequest(); + request->init(completionKind, completionValue, promise); + return request; +} + +/* static */ [[nodiscard]] bool AsyncGeneratorObject::enqueueRequest( + JSContext* cx, Handle<AsyncGeneratorObject*> generator, + Handle<AsyncGeneratorRequest*> request) { + if (generator->isSingleQueue()) { + if (generator->isSingleQueueEmpty()) { + generator->setSingleQueueRequest(request); + return true; + } + + Rooted<ListObject*> queue(cx, ListObject::create(cx)); + if (!queue) { + return false; + } + + RootedValue requestVal(cx, ObjectValue(*generator->singleQueueRequest())); + if (!queue->append(cx, requestVal)) { + return false; + } + requestVal = ObjectValue(*request); + if (!queue->append(cx, requestVal)) { + return false; + } + + generator->setQueue(queue); + return true; + } + + Rooted<ListObject*> queue(cx, generator->queue()); + RootedValue requestVal(cx, ObjectValue(*request)); + return queue->append(cx, requestVal); +} + +/* static */ +AsyncGeneratorRequest* AsyncGeneratorObject::dequeueRequest( + JSContext* cx, Handle<AsyncGeneratorObject*> generator) { + if (generator->isSingleQueue()) { + AsyncGeneratorRequest* request = generator->singleQueueRequest(); + generator->clearSingleQueueRequest(); + return request; + } + + Rooted<ListObject*> queue(cx, generator->queue()); + return &queue->popFirstAs<AsyncGeneratorRequest>(cx); +} + +/* static */ +AsyncGeneratorRequest* AsyncGeneratorObject::peekRequest( + Handle<AsyncGeneratorObject*> generator) { + if (generator->isSingleQueue()) { + return generator->singleQueueRequest(); + } + + return &generator->queue()->getAs<AsyncGeneratorRequest>(0); +} + +const JSClass AsyncGeneratorRequest::class_ = { + "AsyncGeneratorRequest", + JSCLASS_HAS_RESERVED_SLOTS(AsyncGeneratorRequest::Slots)}; + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// AsyncGeneratorRequest Records +// https://tc39.es/ecma262/#sec-asyncgeneratorrequest-records +/* static */ +AsyncGeneratorRequest* AsyncGeneratorRequest::create( + JSContext* cx, CompletionKind completionKind, HandleValue completionValue, + Handle<PromiseObject*> promise) { + AsyncGeneratorRequest* request = + NewObjectWithGivenProto<AsyncGeneratorRequest>(cx, nullptr); + if (!request) { + return nullptr; + } + + request->init(completionKind, completionValue, promise); + return request; +} + +[[nodiscard]] static bool AsyncGeneratorResume( + JSContext* cx, Handle<AsyncGeneratorObject*> generator, + CompletionKind completionKind, HandleValue argument); + +[[nodiscard]] static bool AsyncGeneratorDrainQueue( + JSContext* cx, Handle<AsyncGeneratorObject*> generator); + +[[nodiscard]] static bool AsyncGeneratorCompleteStepNormal( + JSContext* cx, Handle<AsyncGeneratorObject*> generator, HandleValue value, + bool done); + +[[nodiscard]] static bool AsyncGeneratorCompleteStepThrow( + JSContext* cx, Handle<AsyncGeneratorObject*> generator, + HandleValue exception); + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// AsyncGeneratorStart ( generator, generatorBody ) +// https://tc39.es/ecma262/#sec-asyncgeneratorstart +// +// Steps 4.e-j. "return" case. +[[nodiscard]] static bool AsyncGeneratorReturned( + JSContext* cx, Handle<AsyncGeneratorObject*> generator, HandleValue value) { + // Step 4.e. Set generator.[[AsyncGeneratorState]] to completed. + generator->setCompleted(); + + // Step 4.g. If result.[[Type]] is return, set result to + // NormalCompletion(result.[[Value]]). + // (implicit) + + // Step 4.h. Perform ! AsyncGeneratorCompleteStep(generator, result, true). + if (!AsyncGeneratorCompleteStepNormal(cx, generator, value, true)) { + return false; + } + + // Step 4.i. Perform ! AsyncGeneratorDrainQueue(generator). + // Step 4.j. Return undefined. + return AsyncGeneratorDrainQueue(cx, generator); +} + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// AsyncGeneratorStart ( generator, generatorBody ) +// https://tc39.es/ecma262/#sec-asyncgeneratorstart +// +// Steps 4.e-j. "throw" case. +[[nodiscard]] static bool AsyncGeneratorThrown( + JSContext* cx, Handle<AsyncGeneratorObject*> generator) { + // Step 4.e. Set generator.[[AsyncGeneratorState]] to completed. + generator->setCompleted(); + + // Not much we can do about uncatchable exceptions, so just bail. + if (!cx->isExceptionPending()) { + return false; + } + + // Step 4.h. Perform ! AsyncGeneratorCompleteStep(generator, result, true). + RootedValue value(cx); + if (!GetAndClearException(cx, &value)) { + return false; + } + if (!AsyncGeneratorCompleteStepThrow(cx, generator, value)) { + return false; + } + + // Step 4.i. Perform ! AsyncGeneratorDrainQueue(generator). + // Step 4.j. Return undefined. + return AsyncGeneratorDrainQueue(cx, generator); +} + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// AsyncGeneratorUnwrapYieldResumption ( resumptionValue ) +// https://tc39.es/ecma262/#sec-asyncgeneratorunwrapyieldresumption +// +// Steps 4-5. +[[nodiscard]] static bool AsyncGeneratorYieldReturnAwaitedFulfilled( + JSContext* cx, Handle<AsyncGeneratorObject*> generator, HandleValue value) { + MOZ_ASSERT(generator->isAwaitingYieldReturn(), + "YieldReturn-Await fulfilled when not in " + "'AwaitingYieldReturn' state"); + + // Step 4. Assert: awaited.[[Type]] is normal. + // Step 5. Return Completion { [[Type]]: return, [[Value]]: + // awaited.[[Value]], [[Target]]: empty }. + return AsyncGeneratorResume(cx, generator, CompletionKind::Return, value); +} + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// AsyncGeneratorUnwrapYieldResumption ( resumptionValue ) +// https://tc39.es/ecma262/#sec-asyncgeneratorunwrapyieldresumption +// +// Step 3. +[[nodiscard]] static bool AsyncGeneratorYieldReturnAwaitedRejected( + JSContext* cx, Handle<AsyncGeneratorObject*> generator, + HandleValue reason) { + MOZ_ASSERT( + generator->isAwaitingYieldReturn(), + "YieldReturn-Await rejected when not in 'AwaitingYieldReturn' state"); + + // Step 3. If awaited.[[Type]] is throw, return Completion(awaited). + return AsyncGeneratorResume(cx, generator, CompletionKind::Throw, reason); +} + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// AsyncGeneratorUnwrapYieldResumption ( resumptionValue ) +// https://tc39.es/ecma262/#sec-asyncgeneratorunwrapyieldresumption +// +// Steps 1-2. +[[nodiscard]] static bool AsyncGeneratorUnwrapYieldResumptionAndResume( + JSContext* cx, Handle<AsyncGeneratorObject*> generator, + CompletionKind completionKind, HandleValue resumptionValue) { + // Step 1. If resumptionValue.[[Type]] is not return, return + // Completion(resumptionValue). + if (completionKind != CompletionKind::Return) { + return AsyncGeneratorResume(cx, generator, completionKind, resumptionValue); + } + + // Step 2. Let awaited be Await(resumptionValue.[[Value]]). + // + // Since we don't have the place that handles return from yield + // inside the generator, handle the case here, with extra state + // State_AwaitingYieldReturn. + generator->setAwaitingYieldReturn(); + + const PromiseHandler onFulfilled = + PromiseHandler::AsyncGeneratorYieldReturnAwaitedFulfilled; + const PromiseHandler onRejected = + PromiseHandler::AsyncGeneratorYieldReturnAwaitedRejected; + + return InternalAsyncGeneratorAwait(cx, generator, resumptionValue, + onFulfilled, onRejected); +} + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// AsyncGeneratorYield ( value ) +// https://tc39.es/ecma262/#sec-asyncgeneratoryield +// +// Stesp 10-13. +[[nodiscard]] static bool AsyncGeneratorYield( + JSContext* cx, Handle<AsyncGeneratorObject*> generator, HandleValue value) { + // Step 10. Perform + // ! AsyncGeneratorCompleteStep(generator, completion, false, + // previousRealm). + if (!AsyncGeneratorCompleteStepNormal(cx, generator, value, false)) { + return false; + } + + // Step 11. Let queue be generator.[[AsyncGeneratorQueue]]. + // Step 12. If queue is not empty, then + // Step 13. Else, + // (reordered) + if (generator->isQueueEmpty()) { + // Step 13.a. Set generator.[[AsyncGeneratorState]] to suspendedYield. + generator->setSuspendedYield(); + + // Steps 13.b-c are done in caller. + + // Step 13.d. Return undefined. + return true; + } + + // Step 12. If queue is not empty, then + // Step 12.a. NOTE: Execution continues without suspending the generator. + + // Step 12.b. Let toYield be the first element of queue. + Rooted<AsyncGeneratorRequest*> toYield( + cx, AsyncGeneratorObject::peekRequest(generator)); + if (!toYield) { + return false; + } + + // Step 12.c. Let resumptionValue be toYield.[[Completion]]. + CompletionKind completionKind = toYield->completionKind(); + RootedValue resumptionValue(cx, toYield->completionValue()); + + // Step 12.d. Return AsyncGeneratorUnwrapYieldResumption(resumptionValue). + return AsyncGeneratorUnwrapYieldResumptionAndResume( + cx, generator, completionKind, resumptionValue); +} + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// Await in async function +// https://tc39.es/ecma262/#await +// +// Steps 3.c-f. +[[nodiscard]] static bool AsyncGeneratorAwaitedFulfilled( + JSContext* cx, Handle<AsyncGeneratorObject*> generator, HandleValue value) { + MOZ_ASSERT(generator->isExecuting(), + "Await fulfilled when not in 'Executing' state"); + + // Step 3.c. Push asyncContext onto the execution context stack; asyncContext + // is now the running execution context. + // Step 3.d. Resume the suspended evaluation of asyncContext using + // NormalCompletion(value) as the result of the operation that + // suspended it. + // Step 3.f. Return undefined. + return AsyncGeneratorResume(cx, generator, CompletionKind::Normal, value); +} + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// Await in async function +// https://tc39.es/ecma262/#await +// +// Steps 5.c-f. +[[nodiscard]] static bool AsyncGeneratorAwaitedRejected( + JSContext* cx, Handle<AsyncGeneratorObject*> generator, + HandleValue reason) { + MOZ_ASSERT(generator->isExecuting(), + "Await rejected when not in 'Executing' state"); + + // Step 5.c. Push asyncContext onto the execution context stack; asyncContext + // is now the running execution context. + // Step 5.d. Resume the suspended evaluation of asyncContext using + // ThrowCompletion(reason) as the result of the operation that + // suspended it. + // Step 5.f. Return undefined. + return AsyncGeneratorResume(cx, generator, CompletionKind::Throw, reason); +} + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// Await in async function +// https://tc39.es/ecma262/#await +[[nodiscard]] static bool AsyncGeneratorAwait( + JSContext* cx, Handle<AsyncGeneratorObject*> generator, HandleValue value) { + return InternalAsyncGeneratorAwait( + cx, generator, value, PromiseHandler::AsyncGeneratorAwaitedFulfilled, + PromiseHandler::AsyncGeneratorAwaitedRejected); +} + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// AsyncGeneratorCompleteStep ( generator, completion, done [ , realm ] ) +// https://tc39.es/ecma262/#sec-asyncgeneratorcompletestep +// +// "normal" case. +[[nodiscard]] static bool AsyncGeneratorCompleteStepNormal( + JSContext* cx, Handle<AsyncGeneratorObject*> generator, HandleValue value, + bool done) { + // Step 1. Let queue be generator.[[AsyncGeneratorQueue]]. + // Step 2. Assert: queue is not empty. + MOZ_ASSERT(!generator->isQueueEmpty()); + + // Step 3. Let next be the first element of queue. + // Step 4. Remove the first element from queue. + AsyncGeneratorRequest* next = + AsyncGeneratorObject::dequeueRequest(cx, generator); + if (!next) { + return false; + } + + // Step 5. Let promiseCapability be next.[[Capability]]. + Rooted<PromiseObject*> resultPromise(cx, next->promise()); + + generator->cacheRequest(next); + + // Step 6. Let value be completion.[[Value]]. + // (passed by caller) + + // Step 7. If completion.[[Type]] is throw, then + // Step 8. Else, + // Step 8.a. Assert: completion.[[Type]] is normal. + + // Step 8.b. If realm is present, then + // (skipped) + // Step 8.c. Else, + + // Step 8.c.i. Let iteratorResult be ! CreateIterResultObject(value, done). + JSObject* resultObj = CreateIterResultObject(cx, value, done); + if (!resultObj) { + return false; + } + + // Step 8.d. Perform + // ! Call(promiseCapability.[[Resolve]], undefined, + // « iteratorResult »). + RootedValue resultValue(cx, ObjectValue(*resultObj)); + return ResolvePromiseInternal(cx, resultPromise, resultValue); +} + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// AsyncGeneratorCompleteStep ( generator, completion, done [ , realm ] ) +// https://tc39.es/ecma262/#sec-asyncgeneratorcompletestep +// +// "throw" case. +[[nodiscard]] static bool AsyncGeneratorCompleteStepThrow( + JSContext* cx, Handle<AsyncGeneratorObject*> generator, + HandleValue exception) { + // Step 1. Let queue be generator.[[AsyncGeneratorQueue]]. + // Step 2. Assert: queue is not empty. + MOZ_ASSERT(!generator->isQueueEmpty()); + + // Step 3. Let next be the first element of queue. + // Step 4. Remove the first element from queue. + AsyncGeneratorRequest* next = + AsyncGeneratorObject::dequeueRequest(cx, generator); + if (!next) { + return false; + } + + // Step 5. Let promiseCapability be next.[[Capability]]. + Rooted<PromiseObject*> resultPromise(cx, next->promise()); + + generator->cacheRequest(next); + + // Step 6. Let value be completion.[[Value]]. + // (passed by caller) + + // Step 7. If completion.[[Type]] is throw, then + // Step 7.a. Perform + // ! Call(promiseCapability.[[Reject]], undefined, « value »). + return RejectPromiseInternal(cx, resultPromise, exception); +} + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// AsyncGeneratorAwaitReturn ( generator ) +// https://tc39.es/ecma262/#sec-asyncgeneratorawaitreturn +// +// Steps 7.a-e. +[[nodiscard]] static bool AsyncGeneratorAwaitReturnFulfilled( + JSContext* cx, Handle<AsyncGeneratorObject*> generator, HandleValue value) { + MOZ_ASSERT(generator->isAwaitingReturn(), + "AsyncGeneratorResumeNext-Return fulfilled when not in " + "'AwaitingReturn' state"); + + // Step 7.a. Set generator.[[AsyncGeneratorState]] to completed. + generator->setCompleted(); + + // Step 7.b. Let result be NormalCompletion(value). + // Step 7.c. Perform ! AsyncGeneratorCompleteStep(generator, result, true). + if (!AsyncGeneratorCompleteStepNormal(cx, generator, value, true)) { + return false; + } + + // Step 7.d. Perform ! AsyncGeneratorDrainQueue(generator). + // Step 7.e. Return undefined. + return AsyncGeneratorDrainQueue(cx, generator); +} + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// AsyncGeneratorAwaitReturn ( generator ) +// https://tc39.es/ecma262/#sec-asyncgeneratorawaitreturn +// +// Steps 9.a-e. +[[nodiscard]] static bool AsyncGeneratorAwaitReturnRejected( + JSContext* cx, Handle<AsyncGeneratorObject*> generator, HandleValue value) { + MOZ_ASSERT(generator->isAwaitingReturn(), + "AsyncGeneratorResumeNext-Return rejected when not in " + "'AwaitingReturn' state"); + + // Step 9.a. Set generator.[[AsyncGeneratorState]] to completed. + generator->setCompleted(); + + // Step 9.b. Let result be ThrowCompletion(reason). + // Step 9.c. Perform ! AsyncGeneratorCompleteStep(generator, result, true). + if (!AsyncGeneratorCompleteStepThrow(cx, generator, value)) { + return false; + } + + // Step 9.d. Perform ! AsyncGeneratorDrainQueue(generator). + // Step 9.e. Return undefined. + return AsyncGeneratorDrainQueue(cx, generator); +} + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// AsyncGeneratorAwaitReturn ( generator ) +// https://tc39.es/ecma262/#sec-asyncgeneratorawaitreturn +[[nodiscard]] static bool AsyncGeneratorAwaitReturn( + JSContext* cx, Handle<AsyncGeneratorObject*> generator, HandleValue next) { + // Step 1. Let queue be generator.[[AsyncGeneratorQueue]]. + // Step 2. Assert: queue is not empty. + MOZ_ASSERT(!generator->isQueueEmpty()); + + // Step 3. Let next be the first element of queue. + // (passed by caller) + + // Step 4. Let completion be next.[[Completion]]. + // Step 5. Assert: completion.[[Type]] is return. + // (implicit) + + // Steps 6-11. + return InternalAsyncGeneratorAwait( + cx, generator, next, PromiseHandler::AsyncGeneratorAwaitReturnFulfilled, + PromiseHandler::AsyncGeneratorAwaitReturnRejected); +} + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// AsyncGeneratorDrainQueue ( generator ) +// https://tc39.es/ecma262/#sec-asyncgeneratordrainqueue +[[nodiscard]] static bool AsyncGeneratorDrainQueue( + JSContext* cx, Handle<AsyncGeneratorObject*> generator) { + // Step 1. Assert: generator.[[AsyncGeneratorState]] is completed. + MOZ_ASSERT(generator->isCompleted()); + + // Step 2. Let queue be generator.[[AsyncGeneratorQueue]]. + // Step 3. If queue is empty, return. + if (generator->isQueueEmpty()) { + return true; + } + + // Step 4. Let done be false. + // (implicit) + + // Step 5. Repeat, while done is false, + while (true) { + // Step 5.a. Let next be the first element of queue. + Rooted<AsyncGeneratorRequest*> next( + cx, AsyncGeneratorObject::peekRequest(generator)); + if (!next) { + return false; + } + + // Step 5.b. Let completion be next.[[Completion]]. + CompletionKind completionKind = next->completionKind(); + + // Step 5.c. If completion.[[Type]] is return, then + if (completionKind == CompletionKind::Return) { + RootedValue value(cx, next->completionValue()); + + // Step 5.c.i. Set generator.[[AsyncGeneratorState]] to awaiting-return. + generator->setAwaitingReturn(); + + // Step 5.c.ii. Perform ! AsyncGeneratorAwaitReturn(generator). + // Step 5.c.iii. Set done to true. + return AsyncGeneratorAwaitReturn(cx, generator, value); + } + + // Step 5.d. Else, + if (completionKind == CompletionKind::Throw) { + RootedValue value(cx, next->completionValue()); + + // Step 5.d.ii. Perform + // ! AsyncGeneratorCompleteStep(generator, completion, true). + if (!AsyncGeneratorCompleteStepThrow(cx, generator, value)) { + return false; + } + } else { + // Step 5.d.i. If completion.[[Type]] is normal, then + // Step 5.d.i.1. Set completion to NormalCompletion(undefined). + // Step 5.d.ii. Perform + // ! AsyncGeneratorCompleteStep(generator, completion, true). + if (!AsyncGeneratorCompleteStepNormal(cx, generator, UndefinedHandleValue, + true)) { + return false; + } + } + + // Step 5.d.iii. If queue is empty, set done to true. + if (generator->isQueueEmpty()) { + return true; + } + } +} + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// AsyncGeneratorValidate ( generator, generatorBrand ) +// https://tc39.es/ecma262/#sec-asyncgeneratorvalidate +// +// Testing part. +[[nodiscard]] static bool IsAsyncGeneratorValid(HandleValue asyncGenVal) { + // Step 1. Perform + // ? RequireInternalSlot(generator, [[AsyncGeneratorContext]]). + // Step 2. Perform + // ? RequireInternalSlot(generator, [[AsyncGeneratorState]]). + // Step 3. Perform + // ? RequireInternalSlot(generator, [[AsyncGeneratorQueue]]). + // Step 4. If generator.[[GeneratorBrand]] is not the same value as + // generatorBrand, throw a TypeError exception. + return asyncGenVal.isObject() && + asyncGenVal.toObject().canUnwrapAs<AsyncGeneratorObject>(); +} + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// AsyncGeneratorValidate ( generator, generatorBrand ) +// https://tc39.es/ecma262/#sec-asyncgeneratorvalidate +// +// Throwing part. +[[nodiscard]] static bool AsyncGeneratorValidateThrow( + JSContext* cx, MutableHandleValue result) { + Rooted<PromiseObject*> resultPromise( + cx, CreatePromiseObjectForAsyncGenerator(cx)); + if (!resultPromise) { + return false; + } + + RootedValue badGeneratorError(cx); + if (!GetTypeError(cx, JSMSG_NOT_AN_ASYNC_GENERATOR, &badGeneratorError)) { + return false; + } + + if (!RejectPromiseInternal(cx, resultPromise, badGeneratorError)) { + return false; + } + + result.setObject(*resultPromise); + return true; +} + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// AsyncGeneratorEnqueue ( generator, completion, promiseCapability ) +// https://tc39.es/ecma262/#sec-asyncgeneratorenqueue +[[nodiscard]] static bool AsyncGeneratorEnqueue( + JSContext* cx, Handle<AsyncGeneratorObject*> generator, + CompletionKind completionKind, HandleValue completionValue, + Handle<PromiseObject*> resultPromise) { + // Step 1. Let request be + // AsyncGeneratorRequest { [[Completion]]: completion, + // [[Capability]]: promiseCapability }. + Rooted<AsyncGeneratorRequest*> request( + cx, AsyncGeneratorObject::createRequest(cx, generator, completionKind, + completionValue, resultPromise)); + if (!request) { + return false; + } + + // Step 2. Append request to the end of generator.[[AsyncGeneratorQueue]]. + return AsyncGeneratorObject::enqueueRequest(cx, generator, request); +} + +class MOZ_STACK_CLASS MaybeEnterAsyncGeneratorRealm { + mozilla::Maybe<AutoRealm> ar_; + + public: + MaybeEnterAsyncGeneratorRealm() = default; + ~MaybeEnterAsyncGeneratorRealm() = default; + + // Enter async generator's realm, and wrap the method's argument value if + // necessary. + [[nodiscard]] bool maybeEnterAndWrap(JSContext* cx, + Handle<AsyncGeneratorObject*> generator, + MutableHandleValue value) { + if (generator->compartment() == cx->compartment()) { + return true; + } + + ar_.emplace(cx, generator); + return cx->compartment()->wrap(cx, value); + } + + // Leave async generator's realm, and wrap the method's result value if + // necessary. + [[nodiscard]] bool maybeLeaveAndWrap(JSContext* cx, + MutableHandleValue result) { + if (!ar_) { + return true; + } + ar_.reset(); + + return cx->compartment()->wrap(cx, result); + } +}; + +[[nodiscard]] static bool AsyncGeneratorMethodSanityCheck( + JSContext* cx, Handle<AsyncGeneratorObject*> generator) { + if (generator->isCompleted() || generator->isSuspendedStart() || + generator->isSuspendedYield()) { + // The spec assumes the queue is empty when async generator methods are + // called with those state, but our debugger allows calling those methods + // in unexpected state, such as before suspendedStart. + if (MOZ_UNLIKELY(!generator->isQueueEmpty())) { + JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, + JSMSG_SUSPENDED_QUEUE_NOT_EMPTY); + return false; + } + } + + return true; +} + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// AsyncGenerator.prototype.next ( value ) +// https://tc39.es/ecma262/#sec-asyncgenerator-prototype-next +bool js::AsyncGeneratorNext(JSContext* cx, unsigned argc, Value* vp) { + CallArgs args = CallArgsFromVp(argc, vp); + + // Step 3. Let result be AsyncGeneratorValidate(generator, empty). + // Step 4. IfAbruptRejectPromise(result, promiseCapability). + // (reordered) + if (!IsAsyncGeneratorValid(args.thisv())) { + return AsyncGeneratorValidateThrow(cx, args.rval()); + } + + // Step 1. Let generator be the this value. + // (implicit) + Rooted<AsyncGeneratorObject*> generator( + cx, &args.thisv().toObject().unwrapAs<AsyncGeneratorObject>()); + + MaybeEnterAsyncGeneratorRealm maybeEnterRealm; + + RootedValue completionValue(cx, args.get(0)); + if (!maybeEnterRealm.maybeEnterAndWrap(cx, generator, &completionValue)) { + return false; + } + + // Step 2. Let promiseCapability be ! NewPromiseCapability(%Promise%). + Rooted<PromiseObject*> resultPromise( + cx, CreatePromiseObjectForAsyncGenerator(cx)); + if (!resultPromise) { + return false; + } + + if (!AsyncGeneratorMethodSanityCheck(cx, generator)) { + return false; + } + + // Step 5. Let state be generator.[[AsyncGeneratorState]]. + // Step 6. If state is completed, then + if (generator->isCompleted()) { + // Step 6.a. Let iteratorResult be + // ! CreateIterResultObject(undefined, true). + JSObject* resultObj = + CreateIterResultObject(cx, UndefinedHandleValue, true); + if (!resultObj) { + return false; + } + + // Step 6.b. Perform + // ! Call(promiseCapability.[[Resolve]], undefined, + // « iteratorResult »). + RootedValue resultValue(cx, ObjectValue(*resultObj)); + if (!ResolvePromiseInternal(cx, resultPromise, resultValue)) { + return false; + } + } else { + // Step 7. Let completion be NormalCompletion(value). + // Step 8. Perform + // ! AsyncGeneratorEnqueue(generator, completion, + // promiseCapability). + if (!AsyncGeneratorEnqueue(cx, generator, CompletionKind::Normal, + completionValue, resultPromise)) { + return false; + } + + // Step 9. If state is either suspendedStart or suspendedYield, then + if (generator->isSuspendedStart() || generator->isSuspendedYield()) { + RootedValue resumptionValue(cx, completionValue); + // Step 9.a. Perform ! AsyncGeneratorResume(generator, completion). + if (!AsyncGeneratorResume(cx, generator, CompletionKind::Normal, + resumptionValue)) { + return false; + } + } else { + // Step 10. Else, + // Step 10.a. Assert: state is either executing or awaiting-return. + MOZ_ASSERT(generator->isExecuting() || generator->isAwaitingReturn() || + generator->isAwaitingYieldReturn()); + } + } + + // Step 6.c. Return promiseCapability.[[Promise]]. + // and + // Step 11. Return promiseCapability.[[Promise]]. + args.rval().setObject(*resultPromise); + + return maybeEnterRealm.maybeLeaveAndWrap(cx, args.rval()); +} + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// AsyncGenerator.prototype.return ( value ) +// https://tc39.es/ecma262/#sec-asyncgenerator-prototype-return +bool js::AsyncGeneratorReturn(JSContext* cx, unsigned argc, Value* vp) { + CallArgs args = CallArgsFromVp(argc, vp); + + // Step 3. Let result be AsyncGeneratorValidate(generator, empty). + // Step 4. IfAbruptRejectPromise(result, promiseCapability). + // (reordered) + if (!IsAsyncGeneratorValid(args.thisv())) { + return AsyncGeneratorValidateThrow(cx, args.rval()); + } + + // Step 1. Let generator be the this value. + Rooted<AsyncGeneratorObject*> generator( + cx, &args.thisv().toObject().unwrapAs<AsyncGeneratorObject>()); + + MaybeEnterAsyncGeneratorRealm maybeEnterRealm; + + RootedValue completionValue(cx, args.get(0)); + if (!maybeEnterRealm.maybeEnterAndWrap(cx, generator, &completionValue)) { + return false; + } + + // Step 2. Let promiseCapability be ! NewPromiseCapability(%Promise%). + Rooted<PromiseObject*> resultPromise( + cx, CreatePromiseObjectForAsyncGenerator(cx)); + if (!resultPromise) { + return false; + } + + if (!AsyncGeneratorMethodSanityCheck(cx, generator)) { + return false; + } + + // Step 5. Let completion be + // Completion { [[Type]]: return, [[Value]]: value, + // [[Target]]: empty }. + // Step 6. Perform + // ! AsyncGeneratorEnqueue(generator, completion, promiseCapability). + if (!AsyncGeneratorEnqueue(cx, generator, CompletionKind::Return, + completionValue, resultPromise)) { + return false; + } + + // Step 7. Let state be generator.[[AsyncGeneratorState]]. + // Step 8. If state is either suspendedStart or completed, then + if (generator->isSuspendedStart() || generator->isCompleted()) { + // Step 8.a. Set generator.[[AsyncGeneratorState]] to awaiting-return. + generator->setAwaitingReturn(); + + // Step 8.b. Perform ! AsyncGeneratorAwaitReturn(generator). + if (!AsyncGeneratorAwaitReturn(cx, generator, completionValue)) { + return false; + } + } else if (generator->isSuspendedYield()) { + // Step 9. Else if state is suspendedYield, then + + // Step 9.a. Perform ! AsyncGeneratorResume(generator, completion). + if (!AsyncGeneratorUnwrapYieldResumptionAndResume( + cx, generator, CompletionKind::Return, completionValue)) { + return false; + } + } else { + // Step 10. Else, + // Step 10.a. Assert: state is either executing or awaiting-return. + MOZ_ASSERT(generator->isExecuting() || generator->isAwaitingReturn() || + generator->isAwaitingYieldReturn()); + } + + // Step 11. Return promiseCapability.[[Promise]]. + args.rval().setObject(*resultPromise); + + return maybeEnterRealm.maybeLeaveAndWrap(cx, args.rval()); +} + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// AsyncGenerator.prototype.throw ( exception ) +// https://tc39.es/ecma262/#sec-asyncgenerator-prototype-throw +bool js::AsyncGeneratorThrow(JSContext* cx, unsigned argc, Value* vp) { + CallArgs args = CallArgsFromVp(argc, vp); + + // Step 3. Let result be AsyncGeneratorValidate(generator, empty). + // Step 4. IfAbruptRejectPromise(result, promiseCapability). + // (reordered) + if (!IsAsyncGeneratorValid(args.thisv())) { + return AsyncGeneratorValidateThrow(cx, args.rval()); + } + + // Step 1. Let generator be the this value. + Rooted<AsyncGeneratorObject*> generator( + cx, &args.thisv().toObject().unwrapAs<AsyncGeneratorObject>()); + + MaybeEnterAsyncGeneratorRealm maybeEnterRealm; + + RootedValue completionValue(cx, args.get(0)); + if (!maybeEnterRealm.maybeEnterAndWrap(cx, generator, &completionValue)) { + return false; + } + + // Step 2. Let promiseCapability be ! NewPromiseCapability(%Promise%). + Rooted<PromiseObject*> resultPromise( + cx, CreatePromiseObjectForAsyncGenerator(cx)); + if (!resultPromise) { + return false; + } + + if (!AsyncGeneratorMethodSanityCheck(cx, generator)) { + return false; + } + + // Step 5. Let state be generator.[[AsyncGeneratorState]]. + // Step 6. If state is suspendedStart, then + if (generator->isSuspendedStart()) { + // Step 6.a. Set generator.[[AsyncGeneratorState]] to completed. + // Step 6.b. Set state to completed. + generator->setCompleted(); + } + + // Step 7. If state is completed, then + if (generator->isCompleted()) { + // Step 7.a. Perform + // ! Call(promiseCapability.[[Reject]], undefined, « exception »). + if (!RejectPromiseInternal(cx, resultPromise, completionValue)) { + return false; + } + } else { + // Step 8. Let completion be ThrowCompletion(exception). + // Step 9. Perform + // ! AsyncGeneratorEnqueue(generator, completion, + // promiseCapability). + if (!AsyncGeneratorEnqueue(cx, generator, CompletionKind::Throw, + completionValue, resultPromise)) { + return false; + } + + // Step 10. If state is suspendedYield, then + if (generator->isSuspendedYield()) { + // Step 10.a. Perform ! AsyncGeneratorResume(generator, completion). + if (!AsyncGeneratorResume(cx, generator, CompletionKind::Throw, + completionValue)) { + return false; + } + } else { + // Step 11. Else, + // Step 11.a. Assert: state is either executing or awaiting-return. + MOZ_ASSERT(generator->isExecuting() || generator->isAwaitingReturn() || + generator->isAwaitingYieldReturn()); + } + } + + // Step 7.b. Return promiseCapability.[[Promise]]. + // and + // Step 12. Return promiseCapability.[[Promise]]. + args.rval().setObject(*resultPromise); + + return maybeEnterRealm.maybeLeaveAndWrap(cx, args.rval()); +} + +// ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 +// +// AsyncGeneratorResume ( generator, completion ) +// https://tc39.es/ecma262/#sec-asyncgeneratorresume +[[nodiscard]] static bool AsyncGeneratorResume( + JSContext* cx, Handle<AsyncGeneratorObject*> generator, + CompletionKind completionKind, HandleValue argument) { + MOZ_ASSERT(!generator->isClosed(), + "closed generator when resuming async generator"); + MOZ_ASSERT(generator->isSuspended(), + "non-suspended generator when resuming async generator"); + + // Step 1. Assert: generator.[[AsyncGeneratorState]] is either + // suspendedStart or suspendedYield. + // + // NOTE: We're using suspend/resume also for await. and the state can be + // anything. + + // Steps 2-4 are handled in generator. + + // Step 5. Set generator.[[AsyncGeneratorState]] to executing. + generator->setExecuting(); + + // Step 6. Push genContext onto the execution context stack; genContext is + // now the running execution context. + // Step 7. Resume the suspended evaluation of genContext using completion as + // the result of the operation that suspended it. Let result be the + // completion record returned by the resumed computation. + Handle<PropertyName*> funName = completionKind == CompletionKind::Normal + ? cx->names().AsyncGeneratorNext + : completionKind == CompletionKind::Throw + ? cx->names().AsyncGeneratorThrow + : cx->names().AsyncGeneratorReturn; + FixedInvokeArgs<1> args(cx); + args[0].set(argument); + RootedValue thisOrRval(cx, ObjectValue(*generator)); + if (!CallSelfHostedFunction(cx, funName, thisOrRval, args, &thisOrRval)) { + // 25.5.3.2, steps 5.f, 5.g. + if (!generator->isClosed()) { + generator->setClosed(); + } + return AsyncGeneratorThrown(cx, generator); + } + + // 6.2.3.1, steps 2-9. + if (generator->isAfterAwait()) { + return AsyncGeneratorAwait(cx, generator, thisOrRval); + } + + // 25.5.3.7, steps 5-6, 9. + if (generator->isAfterYield()) { + return AsyncGeneratorYield(cx, generator, thisOrRval); + } + + // 25.5.3.2, steps 5.d-g. + return AsyncGeneratorReturned(cx, generator, thisOrRval); +} + +static const JSFunctionSpec async_generator_methods[] = { + JS_FN("next", js::AsyncGeneratorNext, 1, 0), + JS_FN("throw", js::AsyncGeneratorThrow, 1, 0), + JS_FN("return", js::AsyncGeneratorReturn, 1, 0), JS_FS_END}; + +static JSObject* CreateAsyncGeneratorFunction(JSContext* cx, JSProtoKey key) { + RootedObject proto(cx, &cx->global()->getFunctionConstructor()); + Handle<PropertyName*> name = cx->names().AsyncGeneratorFunction; + + // ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 + // + // The AsyncGeneratorFunction Constructor + // https://tc39.es/ecma262/#sec-asyncgeneratorfunction-constructor + return NewFunctionWithProto(cx, AsyncGeneratorConstructor, 1, + FunctionFlags::NATIVE_CTOR, nullptr, name, proto, + gc::AllocKind::FUNCTION, TenuredObject); +} + +static JSObject* CreateAsyncGeneratorFunctionPrototype(JSContext* cx, + JSProtoKey key) { + return NewTenuredObjectWithFunctionPrototype(cx, cx->global()); +} + +static bool AsyncGeneratorFunctionClassFinish(JSContext* cx, + HandleObject asyncGenFunction, + HandleObject asyncGenerator) { + Handle<GlobalObject*> global = cx->global(); + + // Change the "constructor" property to non-writable before adding any other + // properties, so it's still the last property and can be modified without a + // dictionary-mode transition. + MOZ_ASSERT(asyncGenerator->as<NativeObject>().getLastProperty().key() == + NameToId(cx->names().constructor)); + MOZ_ASSERT(!asyncGenerator->as<NativeObject>().inDictionaryMode()); + + RootedValue asyncGenFunctionVal(cx, ObjectValue(*asyncGenFunction)); + if (!DefineDataProperty(cx, asyncGenerator, cx->names().constructor, + asyncGenFunctionVal, JSPROP_READONLY)) { + return false; + } + MOZ_ASSERT(!asyncGenerator->as<NativeObject>().inDictionaryMode()); + + RootedObject asyncIterProto( + cx, GlobalObject::getOrCreateAsyncIteratorPrototype(cx, global)); + if (!asyncIterProto) { + return false; + } + + // ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 + // + // AsyncGenerator Objects + // https://tc39.es/ecma262/#sec-asyncgenerator-objects + RootedObject asyncGenProto(cx, GlobalObject::createBlankPrototypeInheriting( + cx, &PlainObject::class_, asyncIterProto)); + if (!asyncGenProto) { + return false; + } + if (!DefinePropertiesAndFunctions(cx, asyncGenProto, nullptr, + async_generator_methods) || + !DefineToStringTag(cx, asyncGenProto, cx->names().AsyncGenerator)) { + return false; + } + + // ES2022 draft rev 193211a3d889a61e74ef7da1475dfa356e029f29 + // + // Properties of the AsyncGeneratorFunction Prototype Object + // https://tc39.es/ecma262/#sec-properties-of-asyncgeneratorfunction-prototype + if (!LinkConstructorAndPrototype(cx, asyncGenerator, asyncGenProto, + JSPROP_READONLY, JSPROP_READONLY) || + !DefineToStringTag(cx, asyncGenerator, + cx->names().AsyncGeneratorFunction)) { + return false; + } + + global->setAsyncGeneratorPrototype(asyncGenProto); + + return true; +} + +static const ClassSpec AsyncGeneratorFunctionClassSpec = { + CreateAsyncGeneratorFunction, + CreateAsyncGeneratorFunctionPrototype, + nullptr, + nullptr, + nullptr, + nullptr, + AsyncGeneratorFunctionClassFinish, + ClassSpec::DontDefineConstructor}; + +const JSClass js::AsyncGeneratorFunctionClass = { + "AsyncGeneratorFunction", 0, JS_NULL_CLASS_OPS, + &AsyncGeneratorFunctionClassSpec}; + +[[nodiscard]] bool js::AsyncGeneratorPromiseReactionJob( + JSContext* cx, PromiseHandler handler, + Handle<AsyncGeneratorObject*> generator, HandleValue argument) { + // Await's handlers don't return a value, nor throw any exceptions. + // They fail only on OOM. + switch (handler) { + case PromiseHandler::AsyncGeneratorAwaitedFulfilled: + return AsyncGeneratorAwaitedFulfilled(cx, generator, argument); + + case PromiseHandler::AsyncGeneratorAwaitedRejected: + return AsyncGeneratorAwaitedRejected(cx, generator, argument); + + case PromiseHandler::AsyncGeneratorAwaitReturnFulfilled: + return AsyncGeneratorAwaitReturnFulfilled(cx, generator, argument); + + case PromiseHandler::AsyncGeneratorAwaitReturnRejected: + return AsyncGeneratorAwaitReturnRejected(cx, generator, argument); + + case PromiseHandler::AsyncGeneratorYieldReturnAwaitedFulfilled: + return AsyncGeneratorYieldReturnAwaitedFulfilled(cx, generator, argument); + + case PromiseHandler::AsyncGeneratorYieldReturnAwaitedRejected: + return AsyncGeneratorYieldReturnAwaitedRejected(cx, generator, argument); + + default: + MOZ_CRASH("Bad handler in AsyncGeneratorPromiseReactionJob"); + } +} + +// --------------------- +// AsyncFromSyncIterator +// --------------------- + +const JSClass AsyncFromSyncIteratorObject::class_ = { + "AsyncFromSyncIteratorObject", + JSCLASS_HAS_RESERVED_SLOTS(AsyncFromSyncIteratorObject::Slots)}; + +// ES2019 draft rev c012f9c70847559a1d9dc0d35d35b27fec42911e +// 25.1.4.1 CreateAsyncFromSyncIterator +JSObject* js::CreateAsyncFromSyncIterator(JSContext* cx, HandleObject iter, + HandleValue nextMethod) { + // Steps 1-3. + return AsyncFromSyncIteratorObject::create(cx, iter, nextMethod); +} + +// ES2019 draft rev c012f9c70847559a1d9dc0d35d35b27fec42911e +// 25.1.4.1 CreateAsyncFromSyncIterator +/* static */ +JSObject* AsyncFromSyncIteratorObject::create(JSContext* cx, HandleObject iter, + HandleValue nextMethod) { + // Step 1. + RootedObject proto(cx, + GlobalObject::getOrCreateAsyncFromSyncIteratorPrototype( + cx, cx->global())); + if (!proto) { + return nullptr; + } + + AsyncFromSyncIteratorObject* asyncIter = + NewObjectWithGivenProto<AsyncFromSyncIteratorObject>(cx, proto); + if (!asyncIter) { + return nullptr; + } + + // Step 2. + asyncIter->init(iter, nextMethod); + + // Step 3 (Call to 7.4.1 GetIterator). + // 7.4.1 GetIterator, steps 1-5 are a no-op (*). + // 7.4.1 GetIterator, steps 6-8 are implemented in bytecode. + // + // (*) With <https://github.com/tc39/ecma262/issues/1172> fixed. + return asyncIter; +} + +// ES2019 draft rev c012f9c70847559a1d9dc0d35d35b27fec42911e +// 25.1.4.2.1 %AsyncFromSyncIteratorPrototype%.next +static bool AsyncFromSyncIteratorNext(JSContext* cx, unsigned argc, Value* vp) { + CallArgs args = CallArgsFromVp(argc, vp); + return AsyncFromSyncIteratorMethod(cx, args, CompletionKind::Normal); +} + +// ES2019 draft rev c012f9c70847559a1d9dc0d35d35b27fec42911e +// 25.1.4.2.2 %AsyncFromSyncIteratorPrototype%.return +static bool AsyncFromSyncIteratorReturn(JSContext* cx, unsigned argc, + Value* vp) { + CallArgs args = CallArgsFromVp(argc, vp); + return AsyncFromSyncIteratorMethod(cx, args, CompletionKind::Return); +} + +// ES2019 draft rev c012f9c70847559a1d9dc0d35d35b27fec42911e +// 25.1.4.2.3 %AsyncFromSyncIteratorPrototype%.throw +static bool AsyncFromSyncIteratorThrow(JSContext* cx, unsigned argc, + Value* vp) { + CallArgs args = CallArgsFromVp(argc, vp); + return AsyncFromSyncIteratorMethod(cx, args, CompletionKind::Throw); +} + +static const JSFunctionSpec async_from_sync_iter_methods[] = { + JS_FN("next", AsyncFromSyncIteratorNext, 1, 0), + JS_FN("throw", AsyncFromSyncIteratorThrow, 1, 0), + JS_FN("return", AsyncFromSyncIteratorReturn, 1, 0), JS_FS_END}; + +bool GlobalObject::initAsyncFromSyncIteratorProto( + JSContext* cx, Handle<GlobalObject*> global) { + if (global->hasBuiltinProto(ProtoKind::AsyncFromSyncIteratorProto)) { + return true; + } + + RootedObject asyncIterProto( + cx, GlobalObject::getOrCreateAsyncIteratorPrototype(cx, global)); + if (!asyncIterProto) { + return false; + } + + // 25.1.4.2 The %AsyncFromSyncIteratorPrototype% Object + RootedObject asyncFromSyncIterProto( + cx, GlobalObject::createBlankPrototypeInheriting(cx, &PlainObject::class_, + asyncIterProto)); + if (!asyncFromSyncIterProto) { + return false; + } + if (!DefinePropertiesAndFunctions(cx, asyncFromSyncIterProto, nullptr, + async_from_sync_iter_methods) || + !DefineToStringTag(cx, asyncFromSyncIterProto, + cx->names().AsyncFromSyncIterator)) { + return false; + } + + global->initBuiltinProto(ProtoKind::AsyncFromSyncIteratorProto, + asyncFromSyncIterProto); + return true; +} + +// ------------- +// AsyncIterator +// ------------- + +static const JSFunctionSpec async_iterator_proto_methods[] = { + JS_SELF_HOSTED_SYM_FN(asyncIterator, "AsyncIteratorIdentity", 0, 0), + JS_FS_END}; + +static const JSFunctionSpec async_iterator_proto_methods_with_helpers[] = { + JS_SELF_HOSTED_FN("map", "AsyncIteratorMap", 1, 0), + JS_SELF_HOSTED_FN("filter", "AsyncIteratorFilter", 1, 0), + JS_SELF_HOSTED_FN("take", "AsyncIteratorTake", 1, 0), + JS_SELF_HOSTED_FN("drop", "AsyncIteratorDrop", 1, 0), + JS_SELF_HOSTED_FN("asIndexedPairs", "AsyncIteratorAsIndexedPairs", 0, 0), + JS_SELF_HOSTED_FN("flatMap", "AsyncIteratorFlatMap", 1, 0), + JS_SELF_HOSTED_FN("reduce", "AsyncIteratorReduce", 1, 0), + JS_SELF_HOSTED_FN("toArray", "AsyncIteratorToArray", 0, 0), + JS_SELF_HOSTED_FN("forEach", "AsyncIteratorForEach", 1, 0), + JS_SELF_HOSTED_FN("some", "AsyncIteratorSome", 1, 0), + JS_SELF_HOSTED_FN("every", "AsyncIteratorEvery", 1, 0), + JS_SELF_HOSTED_FN("find", "AsyncIteratorFind", 1, 0), + JS_SELF_HOSTED_SYM_FN(asyncIterator, "AsyncIteratorIdentity", 0, 0), + JS_FS_END}; + +bool GlobalObject::initAsyncIteratorProto(JSContext* cx, + Handle<GlobalObject*> global) { + if (global->hasBuiltinProto(ProtoKind::AsyncIteratorProto)) { + return true; + } + + // 25.1.3 The %AsyncIteratorPrototype% Object + RootedObject asyncIterProto( + cx, GlobalObject::createBlankPrototype<PlainObject>(cx, global)); + if (!asyncIterProto) { + return false; + } + if (!DefinePropertiesAndFunctions(cx, asyncIterProto, nullptr, + async_iterator_proto_methods)) { + return false; + } + + global->initBuiltinProto(ProtoKind::AsyncIteratorProto, asyncIterProto); + return true; +} + +// https://tc39.es/proposal-iterator-helpers/#sec-asynciterator as of revision +// 8f10db5. +static bool AsyncIteratorConstructor(JSContext* cx, unsigned argc, Value* vp) { + CallArgs args = CallArgsFromVp(argc, vp); + + // Step 1. + if (!ThrowIfNotConstructing(cx, args, js_AsyncIterator_str)) { + return false; + } + // Throw TypeError if NewTarget is the active function object, preventing the + // Iterator constructor from being used directly. + if (args.callee() == args.newTarget().toObject()) { + JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, + JSMSG_BOGUS_CONSTRUCTOR, js_AsyncIterator_str); + return false; + } + + // Step 2. + RootedObject proto(cx); + if (!GetPrototypeFromBuiltinConstructor(cx, args, JSProto_AsyncIterator, + &proto)) { + return false; + } + + JSObject* obj = NewObjectWithClassProto<AsyncIteratorObject>(cx, proto); + if (!obj) { + return false; + } + + args.rval().setObject(*obj); + return true; +} + +static const ClassSpec AsyncIteratorObjectClassSpec = { + GenericCreateConstructor<AsyncIteratorConstructor, 0, + gc::AllocKind::FUNCTION>, + GenericCreatePrototype<AsyncIteratorObject>, + nullptr, + nullptr, + async_iterator_proto_methods_with_helpers, + nullptr, + nullptr, +}; + +const JSClass AsyncIteratorObject::class_ = { + js_AsyncIterator_str, + JSCLASS_HAS_CACHED_PROTO(JSProto_AsyncIterator), + JS_NULL_CLASS_OPS, + &AsyncIteratorObjectClassSpec, +}; + +const JSClass AsyncIteratorObject::protoClass_ = { + "AsyncIterator.prototype", + JSCLASS_HAS_CACHED_PROTO(JSProto_AsyncIterator), + JS_NULL_CLASS_OPS, + &AsyncIteratorObjectClassSpec, +}; + +// Iterator Helper proposal +static const JSFunctionSpec async_iterator_helper_methods[] = { + JS_SELF_HOSTED_FN("next", "AsyncIteratorHelperNext", 1, 0), + JS_SELF_HOSTED_FN("return", "AsyncIteratorHelperReturn", 1, 0), + JS_SELF_HOSTED_FN("throw", "AsyncIteratorHelperThrow", 1, 0), + JS_FS_END, +}; + +static const JSClass AsyncIteratorHelperPrototypeClass = { + "Async Iterator Helper", 0}; + +const JSClass AsyncIteratorHelperObject::class_ = { + "Async Iterator Helper", + JSCLASS_HAS_RESERVED_SLOTS(AsyncIteratorHelperObject::SlotCount), +}; + +/* static */ +NativeObject* GlobalObject::getOrCreateAsyncIteratorHelperPrototype( + JSContext* cx, Handle<GlobalObject*> global) { + return MaybeNativeObject( + getOrCreateBuiltinProto(cx, global, ProtoKind::AsyncIteratorHelperProto, + initAsyncIteratorHelperProto)); +} + +/* static */ +bool GlobalObject::initAsyncIteratorHelperProto(JSContext* cx, + Handle<GlobalObject*> global) { + if (global->hasBuiltinProto(ProtoKind::AsyncIteratorHelperProto)) { + return true; + } + + RootedObject asyncIterProto( + cx, GlobalObject::getOrCreateAsyncIteratorPrototype(cx, global)); + if (!asyncIterProto) { + return false; + } + + RootedObject asyncIteratorHelperProto( + cx, GlobalObject::createBlankPrototypeInheriting( + cx, &AsyncIteratorHelperPrototypeClass, asyncIterProto)); + if (!asyncIteratorHelperProto) { + return false; + } + if (!DefinePropertiesAndFunctions(cx, asyncIteratorHelperProto, nullptr, + async_iterator_helper_methods)) { + return false; + } + + global->initBuiltinProto(ProtoKind::AsyncIteratorHelperProto, + asyncIteratorHelperProto); + return true; +} + +AsyncIteratorHelperObject* js::NewAsyncIteratorHelper(JSContext* cx) { + RootedObject proto(cx, GlobalObject::getOrCreateAsyncIteratorHelperPrototype( + cx, cx->global())); + if (!proto) { + return nullptr; + } + return NewObjectWithGivenProto<AsyncIteratorHelperObject>(cx, proto); +} |