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Promise.cpp
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Promise.cpp
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/* -*- 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/. */
#include "mozilla/dom/Promise.h"
#include "mozilla/dom/PromiseBinding.h"
#include "mozilla/dom/PromiseResolver.h"
#include "mozilla/Preferences.h"
#include "PromiseCallback.h"
#include "nsContentUtils.h"
#include "nsPIDOMWindow.h"
namespace mozilla {
namespace dom {
// PromiseTask
// This class processes the promise's callbacks with promise's result.
class PromiseTask MOZ_FINAL : public nsRunnable
{
public:
PromiseTask(Promise* aPromise)
: mPromise(aPromise)
{
MOZ_ASSERT(aPromise);
MOZ_COUNT_CTOR(PromiseTask);
}
~PromiseTask()
{
MOZ_COUNT_DTOR(PromiseTask);
}
NS_IMETHOD Run()
{
mPromise->mTaskPending = false;
mPromise->RunTask();
return NS_OK;
}
private:
nsRefPtr<Promise> mPromise;
};
// Promise
NS_IMPL_CYCLE_COLLECTION_CLASS(Promise)
NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(Promise)
NS_IMPL_CYCLE_COLLECTION_UNLINK(mWindow)
NS_IMPL_CYCLE_COLLECTION_UNLINK(mResolver)
NS_IMPL_CYCLE_COLLECTION_UNLINK(mResolveCallbacks);
NS_IMPL_CYCLE_COLLECTION_UNLINK(mRejectCallbacks);
tmp->mResult = JSVAL_VOID;
NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
NS_IMPL_CYCLE_COLLECTION_UNLINK_END
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(Promise)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mWindow)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mResolver)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mResolveCallbacks);
NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mRejectCallbacks);
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_SCRIPT_OBJECTS
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(Promise)
NS_IMPL_CYCLE_COLLECTION_TRACE_JSVAL_MEMBER_CALLBACK(mResult)
NS_IMPL_CYCLE_COLLECTION_TRACE_PRESERVED_WRAPPER
NS_IMPL_CYCLE_COLLECTION_TRACE_END
NS_IMPL_CYCLE_COLLECTING_ADDREF(Promise)
NS_IMPL_CYCLE_COLLECTING_RELEASE(Promise)
NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(Promise)
NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
NS_INTERFACE_MAP_ENTRY(nsISupports)
NS_INTERFACE_MAP_END
Promise::Promise(nsPIDOMWindow* aWindow)
: mWindow(aWindow)
, mResult(JS::UndefinedValue())
, mState(Pending)
, mTaskPending(false)
{
MOZ_COUNT_CTOR(Promise);
NS_HOLD_JS_OBJECTS(this, Promise);
SetIsDOMBinding();
mResolver = new PromiseResolver(this);
}
Promise::~Promise()
{
mResult = JSVAL_VOID;
NS_DROP_JS_OBJECTS(this, Promise);
MOZ_COUNT_DTOR(Promise);
}
JSObject*
Promise::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aScope)
{
return PromiseBinding::Wrap(aCx, aScope, this);
}
/* static */ bool
Promise::PrefEnabled()
{
return Preferences::GetBool("dom.promise.enabled", false);
}
static void
EnterCompartment(Maybe<JSAutoCompartment>& aAc, JSContext* aCx,
const Optional<JS::Handle<JS::Value> >& aValue)
{
// FIXME Bug 878849
if (aValue.WasPassed() && aValue.Value().isObject()) {
JS::Rooted<JSObject*> rooted(aCx, &aValue.Value().toObject());
aAc.construct(aCx, rooted);
}
}
/* static */ already_AddRefed<Promise>
Promise::Constructor(const GlobalObject& aGlobal, JSContext* aCx,
PromiseInit& aInit, ErrorResult& aRv)
{
MOZ_ASSERT(PrefEnabled());
nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(aGlobal.Get());
if (!window) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
nsRefPtr<Promise> promise = new Promise(window);
aInit.Call(promise, *promise->mResolver, aRv,
CallbackObject::eRethrowExceptions);
aRv.WouldReportJSException();
if (aRv.IsJSException()) {
Optional<JS::Handle<JS::Value> > value(aCx);
aRv.StealJSException(aCx, &value.Value());
Maybe<JSAutoCompartment> ac;
EnterCompartment(ac, aCx, value);
promise->mResolver->Reject(aCx, value);
}
return promise.forget();
}
/* static */ already_AddRefed<Promise>
Promise::Resolve(const GlobalObject& aGlobal, JSContext* aCx,
JS::Handle<JS::Value> aValue, ErrorResult& aRv)
{
MOZ_ASSERT(PrefEnabled());
nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(aGlobal.Get());
if (!window) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
nsRefPtr<Promise> promise = new Promise(window);
Optional<JS::Handle<JS::Value> > value(aCx, aValue);
promise->mResolver->Resolve(aCx, value);
return promise.forget();
}
/* static */ already_AddRefed<Promise>
Promise::Reject(const GlobalObject& aGlobal, JSContext* aCx,
JS::Handle<JS::Value> aValue, ErrorResult& aRv)
{
MOZ_ASSERT(PrefEnabled());
nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(aGlobal.Get());
if (!window) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
nsRefPtr<Promise> promise = new Promise(window);
Optional<JS::Handle<JS::Value> > value(aCx, aValue);
promise->mResolver->Reject(aCx, value);
return promise.forget();
}
already_AddRefed<Promise>
Promise::Then(const Optional<OwningNonNull<AnyCallback> >& aResolveCallback,
const Optional<OwningNonNull<AnyCallback> >& aRejectCallback)
{
nsRefPtr<Promise> promise = new Promise(GetParentObject());
nsRefPtr<PromiseCallback> resolveCb =
PromiseCallback::Factory(promise->mResolver,
aResolveCallback.WasPassed()
? &aResolveCallback.Value()
: nullptr,
PromiseCallback::Resolve);
nsRefPtr<PromiseCallback> rejectCb =
PromiseCallback::Factory(promise->mResolver,
aRejectCallback.WasPassed()
? &aRejectCallback.Value()
: nullptr,
PromiseCallback::Reject);
AppendCallbacks(resolveCb, rejectCb);
return promise.forget();
}
already_AddRefed<Promise>
Promise::Catch(const Optional<OwningNonNull<AnyCallback> >& aRejectCallback)
{
Optional<OwningNonNull<AnyCallback> > resolveCb;
return Then(resolveCb, aRejectCallback);
}
void
Promise::AppendCallbacks(PromiseCallback* aResolveCallback,
PromiseCallback* aRejectCallback)
{
if (aResolveCallback) {
mResolveCallbacks.AppendElement(aResolveCallback);
}
if (aRejectCallback) {
mRejectCallbacks.AppendElement(aRejectCallback);
}
// If promise's state is resolved, queue a task to process promise's resolve
// callbacks with promise's result. If promise's state is rejected, queue a task
// to process promise's reject callbacks with promise's result.
if (mState != Pending && !mTaskPending) {
nsRefPtr<PromiseTask> task = new PromiseTask(this);
NS_DispatchToCurrentThread(task);
mTaskPending = true;
}
}
void
Promise::RunTask()
{
MOZ_ASSERT(mState != Pending);
nsTArray<nsRefPtr<PromiseCallback> > callbacks;
callbacks.SwapElements(mState == Resolved ? mResolveCallbacks
: mRejectCallbacks);
mResolveCallbacks.Clear();
mRejectCallbacks.Clear();
JSAutoRequest ar(nsContentUtils::GetSafeJSContext());
Optional<JS::Handle<JS::Value> > value(nsContentUtils::GetSafeJSContext(), mResult);
for (uint32_t i = 0; i < callbacks.Length(); ++i) {
callbacks[i]->Call(value);
}
}
} // namespace dom
} // namespace mozilla