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| -rw-r--r-- | js/src/vm/PromiseObject.h | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/js/src/vm/PromiseObject.h b/js/src/vm/PromiseObject.h new file mode 100644 index 0000000000..22ee3b70dc --- /dev/null +++ b/js/src/vm/PromiseObject.h @@ -0,0 +1,243 @@ +/* -*- 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 vm_PromiseObject_h +#define vm_PromiseObject_h + +#include "mozilla/Assertions.h" // MOZ_ASSERT +#include "mozilla/Attributes.h" // MOZ_MUST_USE + +#include <stdint.h> // int32_t, uint64_t + +#include "js/Class.h" // JSClass +#include "js/Promise.h" // JS::PromiseState +#include "js/RootingAPI.h" // JS::{,Mutable}Handle +#include "js/Value.h" // JS::Value, JS::Int32Value, JS::UndefinedHandleValue +#include "vm/NativeObject.h" // js::NativeObject + +class JS_PUBLIC_API JSObject; + +namespace js { + +class SavedFrame; + +enum PromiseSlots { + // Int32 value with PROMISE_FLAG_* flags below. + PromiseSlot_Flags = 0, + + // * if this promise is pending, reaction objects + // * undefined if there's no reaction + // * maybe-wrapped PromiseReactionRecord if there's only one reacion + // * dense array if there are two or more more reactions + // * if this promise is fulfilled, the resolution value + // * if this promise is rejected, the reason for the rejection + PromiseSlot_ReactionsOrResult, + + // * if this promise is pending, resolve/reject functions. + // This slot holds only the reject function. The resolve function is + // reachable from the reject function's extended slot. + // * if this promise is either fulfilled or rejected, undefined + PromiseSlot_RejectFunction, + + // Promise object's debug info, which is created on demand. + // * if this promise has no debug info, undefined + // * if this promise contains only its process-unique ID, the ID's number + // value + // * otherwise a PromiseDebugInfo object + PromiseSlot_DebugInfo, + + PromiseSlots, +}; + +// This promise is either fulfilled or rejected. +// If this flag is not set, this promise is pending. +#define PROMISE_FLAG_RESOLVED 0x1 + +// If this flag and PROMISE_FLAG_RESOLVED are set, this promise is fulfilled. +// If only PROMISE_FLAG_RESOLVED is set, this promise is rejected. +#define PROMISE_FLAG_FULFILLED 0x2 + +// Indicates the promise has ever had a fulfillment or rejection handler; +// used in unhandled rejection tracking. +#define PROMISE_FLAG_HANDLED 0x4 + +// This promise uses the default resolving functions. +// The PromiseSlot_RejectFunction slot is not used. +#define PROMISE_FLAG_DEFAULT_RESOLVING_FUNCTIONS 0x08 + +// This promise is either the return value of an async function invocation or +// an async generator's method. +#define PROMISE_FLAG_ASYNC 0x10 + +// This promise knows how to propagate information required to keep track of +// whether an activation behavior was in progress when the original promise in +// the promise chain was created. This is a concept defined in the HTML spec: +// https://html.spec.whatwg.org/multipage/interaction.html#triggered-by-user-activation +// It is used by the embedder in order to request SpiderMonkey to keep track of +// this information in a Promise, and also to propagate it to newly created +// promises while processing Promise#then. +#define PROMISE_FLAG_REQUIRES_USER_INTERACTION_HANDLING 0x20 + +// This flag indicates whether an activation behavior was in progress when the +// original promise in the promise chain was created. Activation behavior is a +// concept defined by the HTML spec: +// https://html.spec.whatwg.org/multipage/interaction.html#triggered-by-user-activation +// This flag is only effective when the +// PROMISE_FLAG_REQUIRES_USER_INTERACTION_HANDLING is set. +#define PROMISE_FLAG_HAD_USER_INTERACTION_UPON_CREATION 0x40 + +struct PromiseReactionRecordBuilder; + +class PromiseObject : public NativeObject { + public: + static const unsigned RESERVED_SLOTS = PromiseSlots; + static const JSClass class_; + static const JSClass protoClass_; + static PromiseObject* create(JSContext* cx, JS::Handle<JSObject*> executor, + JS::Handle<JSObject*> proto = nullptr, + bool needsWrapping = false); + + static PromiseObject* createSkippingExecutor(JSContext* cx); + + // Create an instance of the original Promise binding, rejected with the given + // value. + static PromiseObject* unforgeableReject(JSContext* cx, + JS::Handle<JS::Value> value); + + // Create an instance of the original Promise binding, resolved with the given + // value. + // + // However, if |value| is itself a promise -- including from another realm -- + // |value| itself will in some circumstances be returned. This sadly means + // this function must return |JSObject*| and can't return |PromiseObject*|. + static JSObject* unforgeableResolve(JSContext* cx, + JS::Handle<JS::Value> value); + + // Create an instance of the original Promise binding, resolved with the given + // value *that is not a promise* -- from this realm/compartment or from any + // other. + // + // If you don't know for certain that your value will never be a promise, use + // |PromiseObject::unforgeableResolve| instead. + // + // Use |PromiseResolvedWithUndefined| (defined below) if your value is always + // |undefined|. + static PromiseObject* unforgeableResolveWithNonPromise( + JSContext* cx, JS::Handle<JS::Value> value); + + int32_t flags() { return getFixedSlot(PromiseSlot_Flags).toInt32(); } + + void setHandled() { + setFixedSlot(PromiseSlot_Flags, + JS::Int32Value(flags() | PROMISE_FLAG_HANDLED)); + } + + JS::PromiseState state() { + int32_t flags = this->flags(); + if (!(flags & PROMISE_FLAG_RESOLVED)) { + MOZ_ASSERT(!(flags & PROMISE_FLAG_FULFILLED)); + return JS::PromiseState::Pending; + } + if (flags & PROMISE_FLAG_FULFILLED) { + return JS::PromiseState::Fulfilled; + } + return JS::PromiseState::Rejected; + } + + JS::Value reactions() { + MOZ_ASSERT(state() == JS::PromiseState::Pending); + return getFixedSlot(PromiseSlot_ReactionsOrResult); + } + + JS::Value value() { + MOZ_ASSERT(state() == JS::PromiseState::Fulfilled); + return getFixedSlot(PromiseSlot_ReactionsOrResult); + } + + JS::Value reason() { + MOZ_ASSERT(state() == JS::PromiseState::Rejected); + return getFixedSlot(PromiseSlot_ReactionsOrResult); + } + + JS::Value valueOrReason() { + MOZ_ASSERT(state() != JS::PromiseState::Pending); + return getFixedSlot(PromiseSlot_ReactionsOrResult); + } + + static MOZ_MUST_USE bool resolve(JSContext* cx, + JS::Handle<PromiseObject*> promise, + JS::Handle<JS::Value> resolutionValue); + static MOZ_MUST_USE bool reject(JSContext* cx, + JS::Handle<PromiseObject*> promise, + JS::Handle<JS::Value> rejectionValue); + + static void onSettled(JSContext* cx, JS::Handle<PromiseObject*> promise, + JS::Handle<js::SavedFrame*> rejectionStack); + + double allocationTime(); + double resolutionTime(); + JSObject* allocationSite(); + JSObject* resolutionSite(); + double lifetime(); + double timeToResolution() { + MOZ_ASSERT(state() != JS::PromiseState::Pending); + return resolutionTime() - allocationTime(); + } + + MOZ_MUST_USE bool dependentPromises( + JSContext* cx, JS::MutableHandle<GCVector<Value>> values); + + // Return the process-unique ID of this promise. Only used by the debugger. + uint64_t getID(); + + // Apply 'builder' to each reaction record in this promise's list. Used only + // by the Debugger API. + // + // The context cx need not be same-compartment with this promise. (In typical + // use, cx is in a debugger compartment, and this promise is in a debuggee + // compartment.) This function presents data to builder exactly as it appears + // in the reaction records, so the values passed to builder methods could + // potentially be cross-compartment with both cx and this promise. + // + // If this function encounters an error, it will report it to 'cx' and return + // false. If a builder call returns false, iteration stops, and this function + // returns false; the build should set an error on 'cx' as appropriate. + // Otherwise, this function returns true. + MOZ_MUST_USE bool forEachReactionRecord( + JSContext* cx, PromiseReactionRecordBuilder& builder); + + bool isUnhandled() { + MOZ_ASSERT(state() == JS::PromiseState::Rejected); + return !(flags() & PROMISE_FLAG_HANDLED); + } + + bool requiresUserInteractionHandling() { + return (flags() & PROMISE_FLAG_REQUIRES_USER_INTERACTION_HANDLING); + } + + void setRequiresUserInteractionHandling(bool state); + + bool hadUserInteractionUponCreation() { + return (flags() & PROMISE_FLAG_HAD_USER_INTERACTION_UPON_CREATION); + } + + void setHadUserInteractionUponCreation(bool state); + + void copyUserInteractionFlagsFrom(PromiseObject& rhs); +}; + +/** + * Create an instance of the original Promise binding, resolved with the value + * |undefined|. + */ +inline PromiseObject* PromiseResolvedWithUndefined(JSContext* cx) { + return PromiseObject::unforgeableResolveWithNonPromise( + cx, JS::UndefinedHandleValue); +} + +} // namespace js + +#endif // vm_PromiseObject_h |