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| -rw-r--r-- | js/src/builtin/Promise.h | 267 |
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diff --git a/js/src/builtin/Promise.h b/js/src/builtin/Promise.h new file mode 100644 index 0000000000..30b0cc862c --- /dev/null +++ b/js/src/builtin/Promise.h @@ -0,0 +1,267 @@ +/* -*- 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/. */ + +#ifndef builtin_Promise_h +#define builtin_Promise_h + +#include "jstypes.h" // JS_PUBLIC_API + +#include "js/RootingAPI.h" // JS::{,Mutable}Handle +#include "js/TypeDecls.h" // JS::HandleObjectVector + +struct JS_PUBLIC_API JSContext; +class JS_PUBLIC_API JSObject; + +namespace JS { +class CallArgs; +class Value; +} // namespace JS + +namespace js { + +class AsyncFunctionGeneratorObject; +class AsyncGeneratorObject; +class PromiseObject; +class SavedFrame; + +enum class CompletionKind : uint8_t; + +enum class PromiseHandler : uint32_t { + Identity = 0, + Thrower, + + // ES2022 draft rev d03c1ec6e235a5180fa772b6178727c17974cb14 + // + // Await in async function + // https://tc39.es/ecma262/#await + // + // Step 3. fulfilledClosure Abstract Closure. + // Step 5. rejectedClosure Abstract Closure. + AsyncFunctionAwaitedFulfilled, + AsyncFunctionAwaitedRejected, + + // Await in async generator + // https://tc39.es/ecma262/#await + // + // Step 3. fulfilledClosure Abstract Closure. + // Step 5. rejectedClosure Abstract Closure. + AsyncGeneratorAwaitedFulfilled, + AsyncGeneratorAwaitedRejected, + + // AsyncGeneratorAwaitReturn ( generator ) + // https://tc39.es/ecma262/#sec-asyncgeneratorawaitreturn + // + // Step 7. fulfilledClosure Abstract Closure. + // Step 9. rejectedClosure Abstract Closure. + AsyncGeneratorAwaitReturnFulfilled, + AsyncGeneratorAwaitReturnRejected, + + // AsyncGeneratorUnwrapYieldResumption + // https://tc39.es/ecma262/#sec-asyncgeneratorunwrapyieldresumption + // + // Steps 3-5 for awaited.[[Type]] handling. + AsyncGeneratorYieldReturnAwaitedFulfilled, + AsyncGeneratorYieldReturnAwaitedRejected, + + // AsyncFromSyncIteratorContinuation ( result, promiseCapability ) + // https://tc39.es/ecma262/#sec-asyncfromsynciteratorcontinuation + // + // Steps 7. unwrap Abstract Closure. + AsyncFromSyncIteratorValueUnwrapDone, + AsyncFromSyncIteratorValueUnwrapNotDone, + + // One past the maximum allowed PromiseHandler value. + Limit +}; + +// Promise.prototype.then. +extern bool Promise_then(JSContext* cx, unsigned argc, JS::Value* vp); + +// Promise[Symbol.species]. +extern bool Promise_static_species(JSContext* cx, unsigned argc, JS::Value* vp); + +// Promise.resolve. +extern bool Promise_static_resolve(JSContext* cx, unsigned argc, JS::Value* vp); + +/** + * Unforgeable version of the JS builtin Promise.all. + * + * Takes a HandleValueVector of Promise objects and returns a promise that's + * resolved with an array of resolution values when all those promises have + * been resolved, or rejected with the rejection value of the first rejected + * promise. + * + * Asserts that all objects in the `promises` vector are, maybe wrapped, + * instances of `Promise` or a subclass of `Promise`. + */ +[[nodiscard]] JSObject* GetWaitForAllPromise(JSContext* cx, + JS::HandleObjectVector promises); + +/** + * Enqueues resolve/reject reactions in the given Promise's reactions lists + * as though by calling the original value of Promise.prototype.then, and + * without regard to any Promise subclassing used in `promiseObj` itself. + */ +[[nodiscard]] PromiseObject* OriginalPromiseThen( + JSContext* cx, JS::Handle<JSObject*> promiseObj, + JS::Handle<JSObject*> onFulfilled, JS::Handle<JSObject*> onRejected); + +enum class UnhandledRejectionBehavior { Ignore, Report }; + +/** + * React to[0] `unwrappedPromise` (which may not be from the current realm) as + * if by using a fresh promise created for the provided nullable fulfill/reject + * IsCallable objects. + * + * However, no dependent Promise will be created, and mucking with `Promise`, + * `Promise.prototype.then`, and `Promise[Symbol.species]` will not alter this + * function's behavior. + * + * If `unwrappedPromise` rejects and `onRejected_` is null, handling is + * determined by `behavior`. If `behavior == Report`, a fresh Promise will be + * constructed and rejected on the fly (and thus will be reported as unhandled). + * But if `behavior == Ignore`, the rejection is ignored and is not reported as + * unhandled. + * + * Note: Reactions pushed using this function contain a null `promise` field. + * That field is only ever used by devtools, which have to treat these reactions + * specially. + * + * 0. The sense of "react" here is the sense of the term as defined by Web IDL: + * https://heycam.github.io/webidl/#dfn-perform-steps-once-promise-is-settled + */ +[[nodiscard]] extern bool ReactToUnwrappedPromise( + JSContext* cx, JS::Handle<PromiseObject*> unwrappedPromise, + JS::Handle<JSObject*> onFulfilled_, JS::Handle<JSObject*> onRejected_, + UnhandledRejectionBehavior behavior); + +/** + * PromiseResolve ( C, x ) + * + * The abstract operation PromiseResolve, given a constructor and a value, + * returns a new promise resolved with that value. + */ +[[nodiscard]] JSObject* PromiseResolve(JSContext* cx, + JS::Handle<JSObject*> constructor, + JS::Handle<JS::Value> value); + +/** + * Reject |promise| with the value of the current pending exception. + * + * |promise| must be from the current realm. Callers must enter the realm of + * |promise| if they are not already in it. + */ +[[nodiscard]] bool RejectPromiseWithPendingError( + JSContext* cx, JS::Handle<PromiseObject*> promise); + +/** + * Create the promise object which will be used as the return value of an async + * function. + */ +[[nodiscard]] PromiseObject* CreatePromiseObjectForAsync(JSContext* cx); + +/** + * Returns true if the given object is a promise created by + * either CreatePromiseObjectForAsync function or async generator's method. + */ +[[nodiscard]] bool IsPromiseForAsyncFunctionOrGenerator(JSObject* promise); + +[[nodiscard]] bool AsyncFunctionReturned( + JSContext* cx, JS::Handle<PromiseObject*> resultPromise, + JS::Handle<JS::Value> value); + +[[nodiscard]] bool AsyncFunctionThrown(JSContext* cx, + JS::Handle<PromiseObject*> resultPromise, + JS::Handle<JS::Value> reason); + +// Start awaiting `value` in an async function (, but doesn't suspend the +// async function's execution!). Returns the async function's result promise. +[[nodiscard]] JSObject* AsyncFunctionAwait( + JSContext* cx, JS::Handle<AsyncFunctionGeneratorObject*> genObj, + JS::Handle<JS::Value> value); + +// If the await operation can be skipped and the resolution value for `val` can +// be acquired, stored the resolved value to `resolved` and `true` to +// `*canSkip`. Otherwise, stores `false` to `*canSkip`. +[[nodiscard]] bool CanSkipAwait(JSContext* cx, JS::Handle<JS::Value> val, + bool* canSkip); +[[nodiscard]] bool ExtractAwaitValue(JSContext* cx, JS::Handle<JS::Value> val, + JS::MutableHandle<JS::Value> resolved); + +bool AsyncFromSyncIteratorMethod(JSContext* cx, JS::CallArgs& args, + CompletionKind completionKind); + +// Callback for describing promise reaction records, for use with +// PromiseObject::getReactionRecords. +struct PromiseReactionRecordBuilder { + // A reaction record created by a call to 'then' or 'catch', with functions to + // call on resolution or rejection, and the promise that will be settled + // according to the result of calling them. + // + // Note that resolve, reject, and result may not be same-compartment with cx, + // or with the promise we're inspecting. This function presents the values + // exactly as they appear in the reaction record. They may also be wrapped or + // unwrapped. + // + // Some reaction records refer to internal resolution or rejection functions + // that are not naturally represented as debuggee JavaScript functions. In + // this case, resolve and reject may be nullptr. + [[nodiscard]] virtual bool then(JSContext* cx, JS::Handle<JSObject*> resolve, + JS::Handle<JSObject*> reject, + JS::Handle<JSObject*> result) = 0; + + // A reaction record created when one native promise is resolved to another. + // The 'promise' argument is the promise that will be settled in the same way + // the promise this reaction record is attached to is settled. + // + // Note that promise may not be same-compartment with cx. This function + // presents the promise exactly as it appears in the reaction record. + [[nodiscard]] virtual bool direct( + JSContext* cx, JS::Handle<PromiseObject*> unwrappedPromise) = 0; + + // A reaction record that resumes an asynchronous function suspended at an + // await expression. The 'generator' argument is the generator object + // representing the call. + // + // Note that generator may not be same-compartment with cx. This function + // presents the generator exactly as it appears in the reaction record. + [[nodiscard]] virtual bool asyncFunction( + JSContext* cx, + JS::Handle<AsyncFunctionGeneratorObject*> unwrappedGenerator) = 0; + + // A reaction record that resumes an asynchronous generator suspended at an + // await expression. The 'generator' argument is the generator object + // representing the call. + // + // Note that generator may not be same-compartment with cx. This function + // presents the generator exactly as it appears in the reaction record. + [[nodiscard]] virtual bool asyncGenerator( + JSContext* cx, JS::Handle<AsyncGeneratorObject*> unwrappedGenerator) = 0; +}; + +[[nodiscard]] PromiseObject* CreatePromiseObjectForAsyncGenerator( + JSContext* cx); + +[[nodiscard]] bool ResolvePromiseInternal(JSContext* cx, + JS::Handle<JSObject*> promise, + JS::Handle<JS::Value> resolutionVal); +[[nodiscard]] bool RejectPromiseInternal( + JSContext* cx, JS::Handle<PromiseObject*> promise, + JS::Handle<JS::Value> reason, + JS::Handle<SavedFrame*> unwrappedRejectionStack = nullptr); + +[[nodiscard]] bool InternalAsyncGeneratorAwait( + JSContext* cx, JS::Handle<AsyncGeneratorObject*> generator, + JS::Handle<JS::Value> value, PromiseHandler onFulfilled, + PromiseHandler onRejected); + +bool IsPromiseWithDefaultResolvingFunction(PromiseObject* promise); +void SetAlreadyResolvedPromiseWithDefaultResolvingFunction( + PromiseObject* promise); + +} // namespace js + +#endif // builtin_Promise_h |