gecko/dom/promise/Promise.h
2014-11-20 09:51:03 +01:00

339 lines
11 KiB
C++

/* -*- Mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; tab-width: 40 -*- */
/* vim: set ts=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 mozilla_dom_Promise_h
#define mozilla_dom_Promise_h
#include "mozilla/Attributes.h"
#include "mozilla/ErrorResult.h"
#include "mozilla/TimeStamp.h"
#include "mozilla/TypeTraits.h"
#include "mozilla/dom/BindingDeclarations.h"
#include "nsCycleCollectionParticipant.h"
#include "mozilla/dom/PromiseBinding.h"
#include "mozilla/dom/ToJSValue.h"
#include "mozilla/WeakPtr.h"
#include "nsWrapperCache.h"
#include "nsAutoPtr.h"
#include "js/TypeDecls.h"
#include "mozilla/dom/workers/bindings/WorkerFeature.h"
class nsIGlobalObject;
namespace mozilla {
namespace dom {
class AnyCallback;
class DOMError;
class MediaStreamError;
class PromiseCallback;
class PromiseInit;
class PromiseNativeHandler;
class PromiseDebugging;
class Promise;
class PromiseReportRejectFeature : public workers::WorkerFeature
{
// The Promise that owns this feature.
Promise* mPromise;
public:
explicit PromiseReportRejectFeature(Promise* aPromise)
: mPromise(aPromise)
{
MOZ_ASSERT(mPromise);
}
virtual bool
Notify(JSContext* aCx, workers::Status aStatus) MOZ_OVERRIDE;
};
class Promise : public nsISupports,
public nsWrapperCache,
public SupportsWeakPtr<Promise>
{
friend class NativePromiseCallback;
friend class PromiseResolverTask;
friend class PromiseTask;
friend class PromiseReportRejectFeature;
friend class PromiseWorkerProxy;
friend class PromiseWorkerProxyRunnable;
friend class RejectPromiseCallback;
friend class ResolvePromiseCallback;
friend class ThenableResolverTask;
friend class WrapperPromiseCallback;
public:
NS_DECL_CYCLE_COLLECTING_ISUPPORTS
NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(Promise)
MOZ_DECLARE_REFCOUNTED_TYPENAME(Promise)
// Promise creation tries to create a JS reflector for the Promise, so is
// fallible. Furthermore, we don't want to do JS-wrapping on a 0-refcount
// object, so we addref before doing that and return the addrefed pointer
// here.
static already_AddRefed<Promise>
Create(nsIGlobalObject* aGlobal, ErrorResult& aRv);
typedef void (Promise::*MaybeFunc)(JSContext* aCx,
JS::Handle<JS::Value> aValue);
void MaybeResolve(JSContext* aCx,
JS::Handle<JS::Value> aValue);
void MaybeReject(JSContext* aCx,
JS::Handle<JS::Value> aValue);
// Helpers for using Promise from C++.
// Most DOM objects are handled already. To add a new type T, add a
// ToJSValue overload in ToJSValue.h.
// aArg is a const reference so we can pass rvalues like integer constants
template <typename T>
void MaybeResolve(const T& aArg) {
MaybeSomething(aArg, &Promise::MaybeResolve);
}
inline void MaybeReject(nsresult aArg) {
MOZ_ASSERT(NS_FAILED(aArg));
MaybeSomething(aArg, &Promise::MaybeReject);
}
inline void MaybeReject(ErrorResult& aArg) {
MOZ_ASSERT(aArg.Failed());
MaybeSomething(aArg, &Promise::MaybeReject);
}
void MaybeReject(const nsRefPtr<MediaStreamError>& aArg);
// DO NOT USE MaybeRejectBrokenly with in new code. Promises should be
// rejected with Error instances.
// Note: MaybeRejectBrokenly is a template so we can use it with DOMError
// without instantiating the DOMError specialization of MaybeSomething in
// every translation unit that includes this header, because that would
// require use to include DOMError.h either here or in all those translation
// units.
template<typename T>
void MaybeRejectBrokenly(const T& aArg); // Not implemented by default; see
// specializations in the .cpp for
// the T values we support.
// Called by DOM to let us execute our callbacks. May be called recursively.
// Returns true if at least one microtask was processed.
static bool PerformMicroTaskCheckpoint();
// WebIDL
nsIGlobalObject* GetParentObject() const
{
return mGlobal;
}
virtual JSObject*
WrapObject(JSContext* aCx) MOZ_OVERRIDE;
static already_AddRefed<Promise>
Constructor(const GlobalObject& aGlobal, PromiseInit& aInit,
ErrorResult& aRv);
static already_AddRefed<Promise>
Resolve(const GlobalObject& aGlobal,
JS::Handle<JS::Value> aValue, ErrorResult& aRv);
static already_AddRefed<Promise>
Resolve(nsIGlobalObject* aGlobal, JSContext* aCx,
JS::Handle<JS::Value> aValue, ErrorResult& aRv);
static already_AddRefed<Promise>
Reject(const GlobalObject& aGlobal,
JS::Handle<JS::Value> aValue, ErrorResult& aRv);
static already_AddRefed<Promise>
Reject(nsIGlobalObject* aGlobal, JSContext* aCx,
JS::Handle<JS::Value> aValue, ErrorResult& aRv);
already_AddRefed<Promise>
Then(JSContext* aCx, AnyCallback* aResolveCallback,
AnyCallback* aRejectCallback, ErrorResult& aRv);
already_AddRefed<Promise>
Catch(JSContext* aCx, AnyCallback* aRejectCallback, ErrorResult& aRv);
static already_AddRefed<Promise>
All(const GlobalObject& aGlobal,
const Sequence<JS::Value>& aIterable, ErrorResult& aRv);
static already_AddRefed<Promise>
Race(const GlobalObject& aGlobal,
const Sequence<JS::Value>& aIterable, ErrorResult& aRv);
void AppendNativeHandler(PromiseNativeHandler* aRunnable);
protected:
// Do NOT call this unless you're Promise::Create. I wish we could enforce
// that from inside this class too, somehow.
explicit Promise(nsIGlobalObject* aGlobal);
virtual ~Promise();
// Queue an async microtask to current main or worker thread.
static void
DispatchToMicroTask(nsIRunnable* aRunnable);
// Do JS-wrapping after Promise creation.
void CreateWrapper(ErrorResult& aRv);
// Create the JS resolving functions of resolve() and reject(). And provide
// references to the two functions by calling PromiseInit passed from Promise
// constructor.
void CallInitFunction(const GlobalObject& aGlobal, PromiseInit& aInit,
ErrorResult& aRv);
bool IsPending()
{
return mResolvePending;
}
void GetDependentPromises(nsTArray<nsRefPtr<Promise>>& aPromises);
private:
friend class PromiseDebugging;
enum PromiseState {
Pending,
Resolved,
Rejected
};
void SetState(PromiseState aState)
{
MOZ_ASSERT(mState == Pending);
MOZ_ASSERT(aState != Pending);
mState = aState;
}
void SetResult(JS::Handle<JS::Value> aValue)
{
mResult = aValue;
}
// This method enqueues promise's resolve/reject callbacks with promise's
// result. It's executed when the resolver.resolve() or resolver.reject() is
// called or when the promise already has a result and new callbacks are
// appended by then(), catch() or done().
void EnqueueCallbackTasks();
void Settle(JS::Handle<JS::Value> aValue, Promise::PromiseState aState);
void MaybeSettle(JS::Handle<JS::Value> aValue, Promise::PromiseState aState);
void AppendCallbacks(PromiseCallback* aResolveCallback,
PromiseCallback* aRejectCallback);
// If we have been rejected and our mResult is a JS exception,
// report it to the error console.
// Use MaybeReportRejectedOnce() for actual calls.
void MaybeReportRejected();
void MaybeReportRejectedOnce() {
MaybeReportRejected();
RemoveFeature();
mResult = JS::UndefinedValue();
}
void MaybeResolveInternal(JSContext* aCx,
JS::Handle<JS::Value> aValue);
void MaybeRejectInternal(JSContext* aCx,
JS::Handle<JS::Value> aValue);
void ResolveInternal(JSContext* aCx,
JS::Handle<JS::Value> aValue);
void RejectInternal(JSContext* aCx,
JS::Handle<JS::Value> aValue);
template <typename T>
void MaybeSomething(T& aArgument, MaybeFunc aFunc) {
ThreadsafeAutoJSContext cx;
JSObject* wrapper = GetWrapper();
MOZ_ASSERT(wrapper); // We preserved it!
JSAutoCompartment ac(cx, wrapper);
JS::Rooted<JS::Value> val(cx);
if (!ToJSValue(cx, aArgument, &val)) {
HandleException(cx);
return;
}
(this->*aFunc)(cx, val);
}
// Static methods for the PromiseInit functions.
static bool
JSCallback(JSContext *aCx, unsigned aArgc, JS::Value *aVp);
static bool
ThenableResolverCommon(JSContext* aCx, uint32_t /* PromiseCallback::Task */ aTask,
unsigned aArgc, JS::Value* aVp);
static bool
JSCallbackThenableResolver(JSContext *aCx, unsigned aArgc, JS::Value *aVp);
static bool
JSCallbackThenableRejecter(JSContext *aCx, unsigned aArgc, JS::Value *aVp);
static JSObject*
CreateFunction(JSContext* aCx, JSObject* aParent, Promise* aPromise,
int32_t aTask);
static JSObject*
CreateThenableFunction(JSContext* aCx, Promise* aPromise, uint32_t aTask);
void HandleException(JSContext* aCx);
void RemoveFeature();
// Capture the current stack and store it in aTarget. If false is
// returned, an exception is presumably pending on aCx.
bool CaptureStack(JSContext* aCx, JS::Heap<JSObject*>& aTarget);
nsRefPtr<nsIGlobalObject> mGlobal;
nsTArray<nsRefPtr<PromiseCallback> > mResolveCallbacks;
nsTArray<nsRefPtr<PromiseCallback> > mRejectCallbacks;
JS::Heap<JS::Value> mResult;
// A stack that shows where this promise was allocated, if there was
// JS running at the time. Otherwise null.
JS::Heap<JSObject*> mAllocationStack;
// mRejectionStack is only set when the promise is rejected directly from
// script, by calling Promise.reject() or the rejection callback we pass to
// the PromiseInit function. Promises that are rejected internally do not
// have a rejection stack.
JS::Heap<JSObject*> mRejectionStack;
// mFullfillmentStack is only set when the promise is fulfilled directly from
// script, by calling Promise.resolve() or the fulfillment callback we pass to
// the PromiseInit function. Promises that are fulfilled internally do not
// have a fulfillment stack.
JS::Heap<JSObject*> mFullfillmentStack;
PromiseState mState;
bool mHadRejectCallback;
bool mResolvePending;
// If a rejected promise on a worker has no reject callbacks attached, it
// needs to know when the worker is shutting down, to report the error on the
// console before the worker's context is deleted. This feature is used for
// that purpose.
nsAutoPtr<PromiseReportRejectFeature> mFeature;
// The time when this promise was created.
TimeStamp mCreationTimestamp;
// The time when this promise transitioned out of the pending state.
TimeStamp mSettlementTimestamp;
};
} // namespace dom
} // namespace mozilla
#endif // mozilla_dom_Promise_h