| // Copyright 2012 the V8 project authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| (function(global, utils, extrasUtils) { |
| |
| "use strict"; |
| |
| %CheckIsBootstrapping(); |
| |
| // ------------------------------------------------------------------- |
| // Imports |
| |
| var InternalArray = utils.InternalArray; |
| var MakeTypeError; |
| var promiseCombinedDeferredSymbol = |
| utils.ImportNow("promise_combined_deferred_symbol"); |
| var promiseHasHandlerSymbol = |
| utils.ImportNow("promise_has_handler_symbol"); |
| var promiseOnRejectSymbol = utils.ImportNow("promise_on_reject_symbol"); |
| var promiseOnResolveSymbol = |
| utils.ImportNow("promise_on_resolve_symbol"); |
| var promiseRawSymbol = utils.ImportNow("promise_raw_symbol"); |
| var promiseStatusSymbol = utils.ImportNow("promise_status_symbol"); |
| var promiseValueSymbol = utils.ImportNow("promise_value_symbol"); |
| var SpeciesConstructor; |
| var toStringTagSymbol = utils.ImportNow("to_string_tag_symbol"); |
| |
| utils.Import(function(from) { |
| MakeTypeError = from.MakeTypeError; |
| SpeciesConstructor = from.SpeciesConstructor; |
| }); |
| |
| // ------------------------------------------------------------------- |
| |
| // Status values: 0 = pending, +1 = resolved, -1 = rejected |
| var lastMicrotaskId = 0; |
| |
| function CreateResolvingFunctions(promise) { |
| var alreadyResolved = false; |
| |
| var resolve = value => { |
| if (alreadyResolved === true) return; |
| alreadyResolved = true; |
| PromiseResolve(promise, value); |
| }; |
| |
| var reject = reason => { |
| if (alreadyResolved === true) return; |
| alreadyResolved = true; |
| PromiseReject(promise, reason); |
| }; |
| |
| return { |
| __proto__: null, |
| resolve: resolve, |
| reject: reject |
| }; |
| } |
| |
| |
| var GlobalPromise = function Promise(resolver) { |
| if (resolver === promiseRawSymbol) { |
| return %NewObject(GlobalPromise, new.target); |
| } |
| if (IS_UNDEFINED(new.target)) throw MakeTypeError(kNotAPromise, this); |
| if (!IS_CALLABLE(resolver)) |
| throw MakeTypeError(kResolverNotAFunction, resolver); |
| |
| var promise = PromiseInit(%NewObject(GlobalPromise, new.target)); |
| var callbacks = CreateResolvingFunctions(promise); |
| |
| try { |
| %DebugPushPromise(promise, Promise); |
| resolver(callbacks.resolve, callbacks.reject); |
| } catch (e) { |
| %_Call(callbacks.reject, UNDEFINED, e); |
| } finally { |
| %DebugPopPromise(); |
| } |
| |
| return promise; |
| } |
| |
| // Core functionality. |
| |
| function PromiseSet(promise, status, value, onResolve, onReject) { |
| SET_PRIVATE(promise, promiseStatusSymbol, status); |
| SET_PRIVATE(promise, promiseValueSymbol, value); |
| SET_PRIVATE(promise, promiseOnResolveSymbol, onResolve); |
| SET_PRIVATE(promise, promiseOnRejectSymbol, onReject); |
| if (DEBUG_IS_ACTIVE) { |
| %DebugPromiseEvent({ promise: promise, status: status, value: value }); |
| } |
| return promise; |
| } |
| |
| function PromiseCreateAndSet(status, value) { |
| var promise = new GlobalPromise(promiseRawSymbol); |
| // If debug is active, notify about the newly created promise first. |
| if (DEBUG_IS_ACTIVE) PromiseSet(promise, 0, UNDEFINED); |
| return PromiseSet(promise, status, value); |
| } |
| |
| function PromiseInit(promise) { |
| return PromiseSet( |
| promise, 0, UNDEFINED, new InternalArray, new InternalArray) |
| } |
| |
| function PromiseDone(promise, status, value, promiseQueue) { |
| if (GET_PRIVATE(promise, promiseStatusSymbol) === 0) { |
| var tasks = GET_PRIVATE(promise, promiseQueue); |
| if (tasks.length) PromiseEnqueue(value, tasks, status); |
| PromiseSet(promise, status, value); |
| } |
| } |
| |
| function PromiseHandle(value, handler, deferred) { |
| try { |
| %DebugPushPromise(deferred.promise, PromiseHandle); |
| var result = handler(value); |
| deferred.resolve(result); |
| } catch (exception) { |
| try { deferred.reject(exception); } catch (e) { } |
| } finally { |
| %DebugPopPromise(); |
| } |
| } |
| |
| function PromiseEnqueue(value, tasks, status) { |
| var id, name, instrumenting = DEBUG_IS_ACTIVE; |
| %EnqueueMicrotask(function() { |
| if (instrumenting) { |
| %DebugAsyncTaskEvent({ type: "willHandle", id: id, name: name }); |
| } |
| for (var i = 0; i < tasks.length; i += 2) { |
| PromiseHandle(value, tasks[i], tasks[i + 1]) |
| } |
| if (instrumenting) { |
| %DebugAsyncTaskEvent({ type: "didHandle", id: id, name: name }); |
| } |
| }); |
| if (instrumenting) { |
| id = ++lastMicrotaskId; |
| name = status > 0 ? "Promise.resolve" : "Promise.reject"; |
| %DebugAsyncTaskEvent({ type: "enqueue", id: id, name: name }); |
| } |
| } |
| |
| function PromiseIdResolveHandler(x) { return x } |
| function PromiseIdRejectHandler(r) { throw r } |
| |
| function PromiseNopResolver() {} |
| |
| // ------------------------------------------------------------------- |
| // Define exported functions. |
| |
| // For bootstrapper. |
| |
| function IsPromise(x) { |
| return IS_RECEIVER(x) && HAS_DEFINED_PRIVATE(x, promiseStatusSymbol); |
| } |
| |
| function PromiseCreate() { |
| return new GlobalPromise(PromiseNopResolver) |
| } |
| |
| function PromiseResolve(promise, x) { |
| if (x === promise) { |
| return PromiseReject(promise, MakeTypeError(kPromiseCyclic, x)); |
| } |
| if (IS_RECEIVER(x)) { |
| // 25.4.1.3.2 steps 8-12 |
| try { |
| var then = x.then; |
| } catch (e) { |
| return PromiseReject(promise, e); |
| } |
| if (IS_CALLABLE(then)) { |
| // PromiseResolveThenableJob |
| var id, name, instrumenting = DEBUG_IS_ACTIVE; |
| %EnqueueMicrotask(function() { |
| if (instrumenting) { |
| %DebugAsyncTaskEvent({ type: "willHandle", id: id, name: name }); |
| } |
| var callbacks = CreateResolvingFunctions(promise); |
| try { |
| %_Call(then, x, callbacks.resolve, callbacks.reject); |
| } catch (e) { |
| %_Call(callbacks.reject, UNDEFINED, e); |
| } |
| if (instrumenting) { |
| %DebugAsyncTaskEvent({ type: "didHandle", id: id, name: name }); |
| } |
| }); |
| if (instrumenting) { |
| id = ++lastMicrotaskId; |
| name = "PromseResolveThenableJob"; |
| %DebugAsyncTaskEvent({ type: "enqueue", id: id, name: name }); |
| } |
| return; |
| } |
| } |
| PromiseDone(promise, +1, x, promiseOnResolveSymbol); |
| } |
| |
| function PromiseReject(promise, r) { |
| // Check promise status to confirm that this reject has an effect. |
| // Call runtime for callbacks to the debugger or for unhandled reject. |
| if (GET_PRIVATE(promise, promiseStatusSymbol) == 0) { |
| var debug_is_active = DEBUG_IS_ACTIVE; |
| if (debug_is_active || |
| !HAS_DEFINED_PRIVATE(promise, promiseHasHandlerSymbol)) { |
| %PromiseRejectEvent(promise, r, debug_is_active); |
| } |
| } |
| PromiseDone(promise, -1, r, promiseOnRejectSymbol) |
| } |
| |
| // Convenience. |
| |
| function NewPromiseCapability(C) { |
| if (C === GlobalPromise) { |
| // Optimized case, avoid extra closure. |
| var promise = PromiseInit(new GlobalPromise(promiseRawSymbol)); |
| var callbacks = CreateResolvingFunctions(promise); |
| return { |
| promise: promise, |
| resolve: callbacks.resolve, |
| reject: callbacks.reject |
| }; |
| } |
| |
| var result = {promise: UNDEFINED, resolve: UNDEFINED, reject: UNDEFINED }; |
| result.promise = new C((resolve, reject) => { |
| if (!IS_UNDEFINED(result.resolve) || !IS_UNDEFINED(result.reject)) |
| throw MakeTypeError(kPromiseExecutorAlreadyInvoked); |
| result.resolve = resolve; |
| result.reject = reject; |
| }); |
| |
| return result; |
| } |
| |
| function PromiseDeferred() { |
| %IncrementUseCounter(kPromiseDefer); |
| return NewPromiseCapability(this); |
| } |
| |
| function PromiseResolved(x) { |
| %IncrementUseCounter(kPromiseAccept); |
| return %_Call(PromiseCast, this, x); |
| } |
| |
| function PromiseRejected(r) { |
| if (!IS_RECEIVER(this)) { |
| throw MakeTypeError(kCalledOnNonObject, PromiseRejected); |
| } |
| if (this === GlobalPromise) { |
| // Optimized case, avoid extra closure. |
| var promise = PromiseCreateAndSet(-1, r); |
| // The debug event for this would always be an uncaught promise reject, |
| // which is usually simply noise. Do not trigger that debug event. |
| %PromiseRejectEvent(promise, r, false); |
| return promise; |
| } else { |
| var promiseCapability = NewPromiseCapability(this); |
| %_Call(promiseCapability.reject, UNDEFINED, r); |
| return promiseCapability.promise; |
| } |
| } |
| |
| // Multi-unwrapped chaining with thenable coercion. |
| |
| function PromiseThen(onResolve, onReject) { |
| var status = GET_PRIVATE(this, promiseStatusSymbol); |
| if (IS_UNDEFINED(status)) { |
| throw MakeTypeError(kNotAPromise, this); |
| } |
| |
| var constructor = SpeciesConstructor(this, GlobalPromise); |
| onResolve = IS_CALLABLE(onResolve) ? onResolve : PromiseIdResolveHandler; |
| onReject = IS_CALLABLE(onReject) ? onReject : PromiseIdRejectHandler; |
| var deferred = NewPromiseCapability(constructor); |
| switch (status) { |
| case 0: // Pending |
| GET_PRIVATE(this, promiseOnResolveSymbol).push(onResolve, deferred); |
| GET_PRIVATE(this, promiseOnRejectSymbol).push(onReject, deferred); |
| break; |
| case +1: // Resolved |
| PromiseEnqueue(GET_PRIVATE(this, promiseValueSymbol), |
| [onResolve, deferred], |
| +1); |
| break; |
| case -1: // Rejected |
| if (!HAS_DEFINED_PRIVATE(this, promiseHasHandlerSymbol)) { |
| // Promise has already been rejected, but had no handler. |
| // Revoke previously triggered reject event. |
| %PromiseRevokeReject(this); |
| } |
| PromiseEnqueue(GET_PRIVATE(this, promiseValueSymbol), |
| [onReject, deferred], |
| -1); |
| break; |
| } |
| // Mark this promise as having handler. |
| SET_PRIVATE(this, promiseHasHandlerSymbol, true); |
| if (DEBUG_IS_ACTIVE) { |
| %DebugPromiseEvent({ promise: deferred.promise, parentPromise: this }); |
| } |
| return deferred.promise; |
| } |
| |
| // Chain is left around for now as an alias for then |
| function PromiseChain(onResolve, onReject) { |
| %IncrementUseCounter(kPromiseChain); |
| return %_Call(PromiseThen, this, onResolve, onReject); |
| } |
| |
| function PromiseCatch(onReject) { |
| return this.then(UNDEFINED, onReject); |
| } |
| |
| // Combinators. |
| |
| function PromiseCast(x) { |
| if (!IS_RECEIVER(this)) { |
| throw MakeTypeError(kCalledOnNonObject, PromiseCast); |
| } |
| if (IsPromise(x) && x.constructor === this) return x; |
| |
| var promiseCapability = NewPromiseCapability(this); |
| var resolveResult = %_Call(promiseCapability.resolve, UNDEFINED, x); |
| return promiseCapability.promise; |
| } |
| |
| function PromiseAll(iterable) { |
| if (!IS_RECEIVER(this)) { |
| throw MakeTypeError(kCalledOnNonObject, "Promise.all"); |
| } |
| |
| var deferred = NewPromiseCapability(this); |
| var resolutions = new InternalArray(); |
| var count; |
| |
| function CreateResolveElementFunction(index, values, promiseCapability) { |
| var alreadyCalled = false; |
| return (x) => { |
| if (alreadyCalled === true) return; |
| alreadyCalled = true; |
| values[index] = x; |
| if (--count === 0) { |
| var valuesArray = []; |
| %MoveArrayContents(values, valuesArray); |
| %_Call(promiseCapability.resolve, UNDEFINED, valuesArray); |
| } |
| }; |
| } |
| |
| try { |
| var i = 0; |
| count = 1; |
| for (var value of iterable) { |
| var nextPromise = this.resolve(value); |
| ++count; |
| nextPromise.then( |
| CreateResolveElementFunction(i, resolutions, deferred), |
| deferred.reject); |
| SET_PRIVATE(deferred.reject, promiseCombinedDeferredSymbol, deferred); |
| ++i; |
| } |
| |
| // 6.d |
| if (--count === 0) { |
| var valuesArray = []; |
| %MoveArrayContents(resolutions, valuesArray); |
| %_Call(deferred.resolve, UNDEFINED, valuesArray); |
| } |
| |
| } catch (e) { |
| %_Call(deferred.reject, UNDEFINED, e); |
| } |
| return deferred.promise; |
| } |
| |
| function PromiseRace(iterable) { |
| if (!IS_RECEIVER(this)) { |
| throw MakeTypeError(kCalledOnNonObject, PromiseRace); |
| } |
| |
| var deferred = NewPromiseCapability(this); |
| try { |
| for (var value of iterable) { |
| this.resolve(value).then(deferred.resolve, deferred.reject); |
| SET_PRIVATE(deferred.reject, promiseCombinedDeferredSymbol, deferred); |
| } |
| } catch (e) { |
| deferred.reject(e) |
| } |
| return deferred.promise; |
| } |
| |
| |
| // Utility for debugger |
| |
| function PromiseHasUserDefinedRejectHandlerRecursive(promise) { |
| var queue = GET_PRIVATE(promise, promiseOnRejectSymbol); |
| if (IS_UNDEFINED(queue)) return false; |
| for (var i = 0; i < queue.length; i += 2) { |
| var handler = queue[i]; |
| if (handler !== PromiseIdRejectHandler) { |
| var deferred = GET_PRIVATE(handler, promiseCombinedDeferredSymbol); |
| if (IS_UNDEFINED(deferred)) return true; |
| if (PromiseHasUserDefinedRejectHandlerRecursive(deferred.promise)) { |
| return true; |
| } |
| } else if (PromiseHasUserDefinedRejectHandlerRecursive( |
| queue[i + 1].promise)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| // Return whether the promise will be handled by a user-defined reject |
| // handler somewhere down the promise chain. For this, we do a depth-first |
| // search for a reject handler that's not the default PromiseIdRejectHandler. |
| function PromiseHasUserDefinedRejectHandler() { |
| return PromiseHasUserDefinedRejectHandlerRecursive(this); |
| }; |
| |
| // ------------------------------------------------------------------- |
| // Install exported functions. |
| |
| %AddNamedProperty(global, 'Promise', GlobalPromise, DONT_ENUM); |
| %AddNamedProperty(GlobalPromise.prototype, toStringTagSymbol, "Promise", |
| DONT_ENUM | READ_ONLY); |
| |
| utils.InstallFunctions(GlobalPromise, DONT_ENUM, [ |
| "reject", PromiseRejected, |
| "all", PromiseAll, |
| "race", PromiseRace, |
| "resolve", PromiseCast |
| ]); |
| |
| utils.InstallFunctions(GlobalPromise.prototype, DONT_ENUM, [ |
| "then", PromiseThen, |
| "catch", PromiseCatch |
| ]); |
| |
| %InstallToContext([ |
| "promise_catch", PromiseCatch, |
| "promise_chain", PromiseChain, |
| "promise_create", PromiseCreate, |
| "promise_has_user_defined_reject_handler", PromiseHasUserDefinedRejectHandler, |
| "promise_reject", PromiseReject, |
| "promise_resolve", PromiseResolve, |
| "promise_then", PromiseThen, |
| ]); |
| |
| // This allows extras to create promises quickly without building extra |
| // resolve/reject closures, and allows them to later resolve and reject any |
| // promise without having to hold on to those closures forever. |
| utils.InstallFunctions(extrasUtils, 0, [ |
| "createPromise", PromiseCreate, |
| "resolvePromise", PromiseResolve, |
| "rejectPromise", PromiseReject |
| ]); |
| |
| // TODO(v8:4567): Allow experimental natives to remove function prototype |
| [PromiseChain, PromiseDeferred, PromiseResolved].forEach( |
| fn => %FunctionRemovePrototype(fn)); |
| |
| utils.Export(function(to) { |
| to.PromiseChain = PromiseChain; |
| to.PromiseDeferred = PromiseDeferred; |
| to.PromiseResolved = PromiseResolved; |
| }); |
| |
| }) |