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gecko-dev/dom/promise/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 "jsfriendapi.h"
#include "mozilla/dom/OwningNonNull.h"
#include "mozilla/dom/PromiseBinding.h"
#include "mozilla/CycleCollectedJSRuntime.h"
#include "mozilla/Preferences.h"
#include "PromiseCallback.h"
#include "PromiseNativeHandler.h"
#include "PromiseWorkerProxy.h"
#include "nsContentUtils.h"
#include "WorkerPrivate.h"
#include "WorkerRunnable.h"
#include "nsJSPrincipals.h"
#include "nsJSUtils.h"
#include "nsPIDOMWindow.h"
#include "nsJSEnvironment.h"
namespace mozilla {
namespace dom {
using namespace workers;
NS_IMPL_ISUPPORTS0(PromiseNativeHandler)
// 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;
};
class WorkerPromiseTask MOZ_FINAL : public WorkerSameThreadRunnable
{
public:
WorkerPromiseTask(WorkerPrivate* aWorkerPrivate, Promise* aPromise)
: WorkerSameThreadRunnable(aWorkerPrivate)
, mPromise(aPromise)
{
MOZ_ASSERT(aPromise);
MOZ_COUNT_CTOR(WorkerPromiseTask);
}
~WorkerPromiseTask()
{
MOZ_COUNT_DTOR(WorkerPromiseTask);
}
bool
WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate)
{
mPromise->mTaskPending = false;
mPromise->RunTask();
return true;
}
private:
nsRefPtr<Promise> mPromise;
};
class PromiseResolverMixin
{
public:
PromiseResolverMixin(Promise* aPromise,
JS::Handle<JS::Value> aValue,
Promise::PromiseState aState)
: mPromise(aPromise)
, mValue(CycleCollectedJSRuntime::Get()->Runtime(), aValue)
, mState(aState)
{
MOZ_ASSERT(aPromise);
MOZ_ASSERT(mState != Promise::Pending);
MOZ_COUNT_CTOR(PromiseResolverMixin);
}
virtual ~PromiseResolverMixin()
{
NS_ASSERT_OWNINGTHREAD(PromiseResolverMixin);
MOZ_COUNT_DTOR(PromiseResolverMixin);
}
protected:
void
RunInternal()
{
NS_ASSERT_OWNINGTHREAD(PromiseResolverMixin);
mPromise->RunResolveTask(
JS::Handle<JS::Value>::fromMarkedLocation(mValue.address()),
mState, Promise::SyncTask);
}
private:
nsRefPtr<Promise> mPromise;
JS::PersistentRooted<JS::Value> mValue;
Promise::PromiseState mState;
NS_DECL_OWNINGTHREAD;
};
// This class processes the promise's callbacks with promise's result.
class PromiseResolverTask MOZ_FINAL : public nsRunnable,
public PromiseResolverMixin
{
public:
PromiseResolverTask(Promise* aPromise,
JS::Handle<JS::Value> aValue,
Promise::PromiseState aState)
: PromiseResolverMixin(aPromise, aValue, aState)
{}
~PromiseResolverTask()
{}
NS_IMETHOD Run()
{
RunInternal();
return NS_OK;
}
};
class WorkerPromiseResolverTask MOZ_FINAL : public WorkerSameThreadRunnable,
public PromiseResolverMixin
{
public:
WorkerPromiseResolverTask(WorkerPrivate* aWorkerPrivate,
Promise* aPromise,
JS::Handle<JS::Value> aValue,
Promise::PromiseState aState)
: WorkerSameThreadRunnable(aWorkerPrivate),
PromiseResolverMixin(aPromise, aValue, aState)
{}
~WorkerPromiseResolverTask()
{}
bool
WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate)
{
RunInternal();
return true;
}
};
// Promise
NS_IMPL_CYCLE_COLLECTION_CLASS(Promise)
NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(Promise)
tmp->MaybeReportRejectedOnce();
NS_IMPL_CYCLE_COLLECTION_UNLINK(mGlobal)
NS_IMPL_CYCLE_COLLECTION_UNLINK(mResolveCallbacks)
NS_IMPL_CYCLE_COLLECTION_UNLINK(mRejectCallbacks)
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(mGlobal)
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(nsIGlobalObject* aGlobal)
: mGlobal(aGlobal)
, mResult(JS::UndefinedValue())
, mState(Pending)
, mTaskPending(false)
, mHadRejectCallback(false)
, mResolvePending(false)
{
MOZ_ASSERT(mGlobal);
mozilla::HoldJSObjects(this);
SetIsDOMBinding();
}
Promise::~Promise()
{
MaybeReportRejectedOnce();
mozilla::DropJSObjects(this);
}
JSObject*
Promise::WrapObject(JSContext* aCx)
{
return PromiseBinding::Wrap(aCx, this);
}
JSObject*
Promise::GetOrCreateWrapper(JSContext* aCx)
{
if (JSObject* wrapper = GetWrapper()) {
return wrapper;
}
nsIGlobalObject* global = GetParentObject();
MOZ_ASSERT(global);
JS::Rooted<JSObject*> scope(aCx, global->GetGlobalJSObject());
if (!scope) {
JS_ReportError(aCx, "can't get scope");
return nullptr;
}
JSAutoCompartment ac(aCx, scope);
JS::Rooted<JS::Value> val(aCx);
if (!WrapNewBindingObject(aCx, this, &val)) {
MOZ_ASSERT(JS_IsExceptionPending(aCx));
return nullptr;
}
return GetWrapper();
}
void
Promise::MaybeResolve(JSContext* aCx,
JS::Handle<JS::Value> aValue)
{
MaybeResolveInternal(aCx, aValue);
}
void
Promise::MaybeReject(JSContext* aCx,
JS::Handle<JS::Value> aValue)
{
MaybeRejectInternal(aCx, aValue);
}
enum {
SLOT_PROMISE = 0,
SLOT_DATA
};
/* static */ bool
Promise::JSCallback(JSContext* aCx, unsigned aArgc, JS::Value* aVp)
{
JS::CallArgs args = CallArgsFromVp(aArgc, aVp);
JS::Rooted<JS::Value> v(aCx,
js::GetFunctionNativeReserved(&args.callee(),
SLOT_PROMISE));
MOZ_ASSERT(v.isObject());
Promise* promise;
if (NS_FAILED(UNWRAP_OBJECT(Promise, &v.toObject(), promise))) {
return Throw(aCx, NS_ERROR_UNEXPECTED);
}
v = js::GetFunctionNativeReserved(&args.callee(), SLOT_DATA);
PromiseCallback::Task task = static_cast<PromiseCallback::Task>(v.toInt32());
if (task == PromiseCallback::Resolve) {
promise->MaybeResolveInternal(aCx, args.get(0));
} else {
promise->MaybeRejectInternal(aCx, args.get(0));
}
return true;
}
/*
* Utilities for thenable callbacks.
*
* A thenable is a { then: function(resolve, reject) { } }.
* `then` is called with a resolve and reject callback pair.
* Since only one of these should be called at most once (first call wins), the
* two keep a reference to each other in SLOT_DATA. When either of them is
* called, the references are cleared. Further calls are ignored.
*/
namespace {
void
LinkThenableCallables(JSContext* aCx, JS::Handle<JSObject*> aResolveFunc,
JS::Handle<JSObject*> aRejectFunc)
{
js::SetFunctionNativeReserved(aResolveFunc, SLOT_DATA,
JS::ObjectValue(*aRejectFunc));
js::SetFunctionNativeReserved(aRejectFunc, SLOT_DATA,
JS::ObjectValue(*aResolveFunc));
}
/*
* Returns false if callback was already called before, otherwise breaks the
* links and returns true.
*/
bool
MarkAsCalledIfNotCalledBefore(JSContext* aCx, JS::Handle<JSObject*> aFunc)
{
JS::Value otherFuncVal = js::GetFunctionNativeReserved(aFunc, SLOT_DATA);
if (!otherFuncVal.isObject()) {
return false;
}
JSObject* otherFuncObj = &otherFuncVal.toObject();
MOZ_ASSERT(js::GetFunctionNativeReserved(otherFuncObj, SLOT_DATA).isObject());
// Break both references.
js::SetFunctionNativeReserved(aFunc, SLOT_DATA, JS::UndefinedValue());
js::SetFunctionNativeReserved(otherFuncObj, SLOT_DATA, JS::UndefinedValue());
return true;
}
Promise*
GetPromise(JSContext* aCx, JS::Handle<JSObject*> aFunc)
{
JS::Value promiseVal = js::GetFunctionNativeReserved(aFunc, SLOT_PROMISE);
MOZ_ASSERT(promiseVal.isObject());
Promise* promise;
UNWRAP_OBJECT(Promise, &promiseVal.toObject(), promise);
return promise;
}
};
/*
* Common bits of (JSCallbackThenableResolver/JSCallbackThenableRejecter).
* Resolves/rejects the Promise if it is ok to do so, based on whether either of
* the callbacks have been called before or not.
*/
/* static */ bool
Promise::ThenableResolverCommon(JSContext* aCx, uint32_t aTask,
unsigned aArgc, JS::Value* aVp)
{
JS::CallArgs args = CallArgsFromVp(aArgc, aVp);
JS::Rooted<JSObject*> thisFunc(aCx, &args.callee());
if (!MarkAsCalledIfNotCalledBefore(aCx, thisFunc)) {
// A function from this pair has been called before.
return true;
}
Promise* promise = GetPromise(aCx, thisFunc);
MOZ_ASSERT(promise);
if (aTask == PromiseCallback::Resolve) {
promise->ResolveInternal(aCx, args.get(0), SyncTask);
} else {
promise->RejectInternal(aCx, args.get(0), SyncTask);
}
return true;
}
/* static */ bool
Promise::JSCallbackThenableResolver(JSContext* aCx,
unsigned aArgc, JS::Value* aVp)
{
return ThenableResolverCommon(aCx, PromiseCallback::Resolve, aArgc, aVp);
}
/* static */ bool
Promise::JSCallbackThenableRejecter(JSContext* aCx,
unsigned aArgc, JS::Value* aVp)
{
return ThenableResolverCommon(aCx, PromiseCallback::Reject, aArgc, aVp);
}
/* static */ JSObject*
Promise::CreateFunction(JSContext* aCx, JSObject* aParent, Promise* aPromise,
int32_t aTask)
{
JSFunction* func = js::NewFunctionWithReserved(aCx, JSCallback,
1 /* nargs */, 0 /* flags */,
aParent, nullptr);
if (!func) {
return nullptr;
}
JS::Rooted<JSObject*> obj(aCx, JS_GetFunctionObject(func));
JS::Rooted<JS::Value> promiseObj(aCx);
if (!dom::WrapNewBindingObject(aCx, aPromise, &promiseObj)) {
return nullptr;
}
js::SetFunctionNativeReserved(obj, SLOT_PROMISE, promiseObj);
js::SetFunctionNativeReserved(obj, SLOT_DATA, JS::Int32Value(aTask));
return obj;
}
/* static */ JSObject*
Promise::CreateThenableFunction(JSContext* aCx, Promise* aPromise, uint32_t aTask)
{
JSNative whichFunc =
aTask == PromiseCallback::Resolve ? JSCallbackThenableResolver :
JSCallbackThenableRejecter ;
JSFunction* func = js::NewFunctionWithReserved(aCx, whichFunc,
1 /* nargs */, 0 /* flags */,
nullptr, nullptr);
if (!func) {
return nullptr;
}
JS::Rooted<JSObject*> obj(aCx, JS_GetFunctionObject(func));
JS::Rooted<JS::Value> promiseObj(aCx);
if (!dom::WrapNewBindingObject(aCx, aPromise, &promiseObj)) {
return nullptr;
}
js::SetFunctionNativeReserved(obj, SLOT_PROMISE, promiseObj);
return obj;
}
/* static */ already_AddRefed<Promise>
Promise::Constructor(const GlobalObject& aGlobal,
PromiseInit& aInit, ErrorResult& aRv)
{
JSContext* cx = aGlobal.GetContext();
nsCOMPtr<nsIGlobalObject> global;
global = do_QueryInterface(aGlobal.GetAsSupports());
if (!global) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
nsRefPtr<Promise> promise = new Promise(global);
JS::Rooted<JSObject*> resolveFunc(cx,
CreateFunction(cx, aGlobal.Get(), promise,
PromiseCallback::Resolve));
if (!resolveFunc) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
JS::Rooted<JSObject*> rejectFunc(cx,
CreateFunction(cx, aGlobal.Get(), promise,
PromiseCallback::Reject));
if (!rejectFunc) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
aInit.Call(resolveFunc, rejectFunc, aRv, CallbackObject::eRethrowExceptions);
aRv.WouldReportJSException();
if (aRv.IsJSException()) {
JS::Rooted<JS::Value> value(cx);
aRv.StealJSException(cx, &value);
// we want the same behavior as this JS implementation:
// function Promise(arg) { try { arg(a, b); } catch (e) { this.reject(e); }}
if (!JS_WrapValue(cx, &value)) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
promise->MaybeRejectInternal(cx, value);
}
return promise.forget();
}
/* static */ already_AddRefed<Promise>
Promise::Resolve(const GlobalObject& aGlobal, JSContext* aCx,
JS::Handle<JS::Value> aValue, ErrorResult& aRv)
{
// If a Promise was passed, just return it.
if (aValue.isObject()) {
JS::Rooted<JSObject*> valueObj(aCx, &aValue.toObject());
Promise* nextPromise;
nsresult rv = UNWRAP_OBJECT(Promise, valueObj, nextPromise);
if (NS_SUCCEEDED(rv)) {
nsRefPtr<Promise> addRefed = nextPromise;
return addRefed.forget();
}
}
nsCOMPtr<nsIGlobalObject> global =
do_QueryInterface(aGlobal.GetAsSupports());
if (!global) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
return Resolve(global, aCx, aValue, aRv);
}
/* static */ already_AddRefed<Promise>
Promise::Resolve(nsIGlobalObject* aGlobal, JSContext* aCx,
JS::Handle<JS::Value> aValue, ErrorResult& aRv)
{
nsRefPtr<Promise> promise = new Promise(aGlobal);
promise->MaybeResolveInternal(aCx, aValue);
return promise.forget();
}
/* static */ already_AddRefed<Promise>
Promise::Reject(const GlobalObject& aGlobal, JSContext* aCx,
JS::Handle<JS::Value> aValue, ErrorResult& aRv)
{
nsCOMPtr<nsIGlobalObject> global =
do_QueryInterface(aGlobal.GetAsSupports());
if (!global) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
return Reject(global, aCx, aValue, aRv);
}
/* static */ already_AddRefed<Promise>
Promise::Reject(nsIGlobalObject* aGlobal, JSContext* aCx,
JS::Handle<JS::Value> aValue, ErrorResult& aRv)
{
nsRefPtr<Promise> promise = new Promise(aGlobal);
promise->MaybeRejectInternal(aCx, aValue);
return promise.forget();
}
already_AddRefed<Promise>
Promise::Then(JSContext* aCx, AnyCallback* aResolveCallback,
AnyCallback* aRejectCallback)
{
nsRefPtr<Promise> promise = new Promise(GetParentObject());
JS::Rooted<JSObject*> global(aCx, JS::CurrentGlobalOrNull(aCx));
nsRefPtr<PromiseCallback> resolveCb =
PromiseCallback::Factory(promise, global, aResolveCallback,
PromiseCallback::Resolve);
nsRefPtr<PromiseCallback> rejectCb =
PromiseCallback::Factory(promise, global, aRejectCallback,
PromiseCallback::Reject);
AppendCallbacks(resolveCb, rejectCb);
return promise.forget();
}
already_AddRefed<Promise>
Promise::Catch(JSContext* aCx, AnyCallback* aRejectCallback)
{
nsRefPtr<AnyCallback> resolveCb;
return Then(aCx, resolveCb, aRejectCallback);
}
/**
* The CountdownHolder class encapsulates Promise.all countdown functions and
* the countdown holder parts of the Promises spec. It maintains the result
* array and AllResolveHandlers use SetValue() to set the array indices.
*/
class CountdownHolder MOZ_FINAL : public nsISupports
{
public:
NS_DECL_CYCLE_COLLECTING_ISUPPORTS
NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(CountdownHolder)
CountdownHolder(const GlobalObject& aGlobal, Promise* aPromise,
uint32_t aCountdown)
: mPromise(aPromise), mCountdown(aCountdown)
{
MOZ_ASSERT(aCountdown != 0);
JSContext* cx = aGlobal.GetContext();
// The only time aGlobal.GetContext() and aGlobal.Get() are not
// same-compartment is when we're called via Xrays, and in that situation we
// in fact want to create the array in the callee compartment
JSAutoCompartment ac(cx, aGlobal.Get());
mValues = JS_NewArrayObject(cx, aCountdown);
mozilla::HoldJSObjects(this);
}
~CountdownHolder()
{
mozilla::DropJSObjects(this);
}
void SetValue(uint32_t index, const JS::Handle<JS::Value> aValue)
{
MOZ_ASSERT(mCountdown > 0);
ThreadsafeAutoSafeJSContext cx;
JSAutoCompartment ac(cx, mValues);
{
AutoDontReportUncaught silenceReporting(cx);
JS::Rooted<JS::Value> value(cx, aValue);
JS::Rooted<JSObject*> values(cx, mValues);
if (!JS_WrapValue(cx, &value) ||
!JS_DefineElement(cx, values, index, value, JSPROP_ENUMERATE)) {
MOZ_ASSERT(JS_IsExceptionPending(cx));
JS::Rooted<JS::Value> exn(cx);
JS_GetPendingException(cx, &exn);
mPromise->MaybeReject(cx, exn);
}
}
--mCountdown;
if (mCountdown == 0) {
JS::Rooted<JS::Value> result(cx, JS::ObjectValue(*mValues));
mPromise->MaybeResolve(cx, result);
}
}
private:
nsRefPtr<Promise> mPromise;
uint32_t mCountdown;
JS::Heap<JSObject*> mValues;
};
NS_IMPL_CYCLE_COLLECTING_ADDREF(CountdownHolder)
NS_IMPL_CYCLE_COLLECTING_RELEASE(CountdownHolder)
NS_IMPL_CYCLE_COLLECTION_CLASS(CountdownHolder)
NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(CountdownHolder)
NS_INTERFACE_MAP_ENTRY(nsISupports)
NS_INTERFACE_MAP_END
NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(CountdownHolder)
NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mValues)
NS_IMPL_CYCLE_COLLECTION_TRACE_END
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(CountdownHolder)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_SCRIPT_OBJECTS
NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mPromise)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(CountdownHolder)
NS_IMPL_CYCLE_COLLECTION_UNLINK(mPromise)
tmp->mValues = nullptr;
NS_IMPL_CYCLE_COLLECTION_UNLINK_END
/**
* An AllResolveHandler is the per-promise part of the Promise.all() algorithm.
* Every Promise in the handler is handed an instance of this as a resolution
* handler and it sets the relevant index in the CountdownHolder.
*/
class AllResolveHandler MOZ_FINAL : public PromiseNativeHandler
{
public:
NS_DECL_CYCLE_COLLECTING_ISUPPORTS
NS_DECL_CYCLE_COLLECTION_CLASS(AllResolveHandler)
AllResolveHandler(CountdownHolder* aHolder, uint32_t aIndex)
: mCountdownHolder(aHolder), mIndex(aIndex)
{
MOZ_ASSERT(aHolder);
}
~AllResolveHandler()
{
}
void
ResolvedCallback(JSContext* aCx, JS::Handle<JS::Value> aValue)
{
mCountdownHolder->SetValue(mIndex, aValue);
}
void
RejectedCallback(JSContext* aCx, JS::Handle<JS::Value> aValue)
{
// Should never be attached to Promise as a reject handler.
MOZ_ASSERT(false, "AllResolveHandler should never be attached to a Promise's reject handler!");
}
private:
nsRefPtr<CountdownHolder> mCountdownHolder;
uint32_t mIndex;
};
NS_IMPL_CYCLE_COLLECTING_ADDREF(AllResolveHandler)
NS_IMPL_CYCLE_COLLECTING_RELEASE(AllResolveHandler)
NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(AllResolveHandler)
NS_INTERFACE_MAP_END_INHERITING(PromiseNativeHandler)
NS_IMPL_CYCLE_COLLECTION(AllResolveHandler, mCountdownHolder)
/* static */ already_AddRefed<Promise>
Promise::All(const GlobalObject& aGlobal, JSContext* aCx,
const Sequence<JS::Value>& aIterable, ErrorResult& aRv)
{
nsCOMPtr<nsIGlobalObject> global =
do_QueryInterface(aGlobal.GetAsSupports());
if (!global) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
if (aIterable.Length() == 0) {
JS::Rooted<JSObject*> empty(aCx, JS_NewArrayObject(aCx, 0));
if (!empty) {
aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
return nullptr;
}
JS::Rooted<JS::Value> value(aCx, JS::ObjectValue(*empty));
return Promise::Resolve(aGlobal, aCx, value, aRv);
}
nsRefPtr<Promise> promise = new Promise(global);
nsRefPtr<CountdownHolder> holder =
new CountdownHolder(aGlobal, promise, aIterable.Length());
JS::Rooted<JSObject*> obj(aCx, JS::CurrentGlobalOrNull(aCx));
if (!obj) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
nsRefPtr<PromiseCallback> rejectCb = new RejectPromiseCallback(promise, obj);
for (uint32_t i = 0; i < aIterable.Length(); ++i) {
JS::Rooted<JS::Value> value(aCx, aIterable.ElementAt(i));
nsRefPtr<Promise> nextPromise = Promise::Resolve(aGlobal, aCx, value, aRv);
MOZ_ASSERT(!aRv.Failed());
nsRefPtr<PromiseNativeHandler> resolveHandler =
new AllResolveHandler(holder, i);
nsRefPtr<PromiseCallback> resolveCb =
new NativePromiseCallback(resolveHandler, Resolved);
// Every promise gets its own resolve callback, which will set the right
// index in the array to the resolution value.
nextPromise->AppendCallbacks(resolveCb, rejectCb);
}
return promise.forget();
}
/* static */ already_AddRefed<Promise>
Promise::Race(const GlobalObject& aGlobal, JSContext* aCx,
const Sequence<JS::Value>& aIterable, ErrorResult& aRv)
{
nsCOMPtr<nsIGlobalObject> global =
do_QueryInterface(aGlobal.GetAsSupports());
if (!global) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
JS::Rooted<JSObject*> obj(aCx, JS::CurrentGlobalOrNull(aCx));
if (!obj) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
nsRefPtr<Promise> promise = new Promise(global);
nsRefPtr<PromiseCallback> resolveCb =
new ResolvePromiseCallback(promise, obj);
nsRefPtr<PromiseCallback> rejectCb = new RejectPromiseCallback(promise, obj);
for (uint32_t i = 0; i < aIterable.Length(); ++i) {
JS::Rooted<JS::Value> value(aCx, aIterable.ElementAt(i));
nsRefPtr<Promise> nextPromise = Promise::Resolve(aGlobal, aCx, value, aRv);
// According to spec, Resolve can throw, but our implementation never does.
// Well it does when window isn't passed on the main thread, but that is an
// implementation detail which should never be reached since we are checking
// for window above. Remove this when subclassing is supported.
MOZ_ASSERT(!aRv.Failed());
nextPromise->AppendCallbacks(resolveCb, rejectCb);
}
return promise.forget();
}
void
Promise::AppendNativeHandler(PromiseNativeHandler* aRunnable)
{
nsRefPtr<PromiseCallback> resolveCb =
new NativePromiseCallback(aRunnable, Resolved);
nsRefPtr<PromiseCallback> rejectCb =
new NativePromiseCallback(aRunnable, Rejected);
AppendCallbacks(resolveCb, rejectCb);
}
void
Promise::AppendCallbacks(PromiseCallback* aResolveCallback,
PromiseCallback* aRejectCallback)
{
if (aResolveCallback) {
mResolveCallbacks.AppendElement(aResolveCallback);
}
if (aRejectCallback) {
mHadRejectCallback = true;
mRejectCallbacks.AppendElement(aRejectCallback);
// Now that there is a callback, we don't need to report anymore.
RemoveFeature();
}
// If promise's state is resolved, queue a task to process our resolve
// callbacks with promise's result. If promise's state is rejected, queue a
// task to process our reject callbacks with promise's result.
if (mState != Pending && !mTaskPending) {
if (MOZ_LIKELY(NS_IsMainThread())) {
nsRefPtr<PromiseTask> task = new PromiseTask(this);
NS_DispatchToCurrentThread(task);
} else {
WorkerPrivate* worker = GetCurrentThreadWorkerPrivate();
MOZ_ASSERT(worker);
nsRefPtr<WorkerPromiseTask> task = new WorkerPromiseTask(worker, this);
task->Dispatch(worker->GetJSContext());
}
mTaskPending = true;
}
}
void
Promise::RunTask()
{
MOZ_ASSERT(mState != Pending);
nsTArray<nsRefPtr<PromiseCallback>> callbacks;
callbacks.SwapElements(mState == Resolved ? mResolveCallbacks
: mRejectCallbacks);
mResolveCallbacks.Clear();
mRejectCallbacks.Clear();
ThreadsafeAutoJSContext cx;
JS::Rooted<JS::Value> value(cx, mResult);
JS::Rooted<JSObject*> wrapper(cx, GetOrCreateWrapper(cx));
if (!wrapper) {
return;
}
JSAutoCompartment ac(cx, wrapper);
if (!MaybeWrapValue(cx, &value)) {
return;
}
for (uint32_t i = 0; i < callbacks.Length(); ++i) {
callbacks[i]->Call(cx, value);
}
}
void
Promise::MaybeReportRejected()
{
if (mState != Rejected || mHadRejectCallback || mResult.isUndefined()) {
return;
}
if (!mResult.isObject()) {
return;
}
ThreadsafeAutoJSContext cx;
JS::Rooted<JSObject*> obj(cx, &mResult.toObject());
JSAutoCompartment ac(cx, obj);
JSErrorReport* report = JS_ErrorFromException(cx, obj);
if (!report) {
return;
}
// Remains null in case of worker.
nsCOMPtr<nsPIDOMWindow> win;
bool isChromeError = false;
if (MOZ_LIKELY(NS_IsMainThread())) {
win =
do_QueryInterface(nsJSUtils::GetStaticScriptGlobal(obj));
nsIPrincipal* principal = nsContentUtils::GetObjectPrincipal(obj);
isChromeError = nsContentUtils::IsSystemPrincipal(principal);
} else {
WorkerPrivate* worker = GetCurrentThreadWorkerPrivate();
MOZ_ASSERT(worker);
isChromeError = worker->IsChromeWorker();
}
// Now post an event to do the real reporting async
// Since Promises preserve their wrapper, it is essential to nsRefPtr<> the
// AsyncErrorReporter, otherwise if the call to DispatchToMainThread fails, it
// will leak. See Bug 958684.
nsRefPtr<AsyncErrorReporter> r =
new AsyncErrorReporter(JS_GetObjectRuntime(obj),
report,
nullptr,
isChromeError,
win);
NS_DispatchToMainThread(r);
}
void
Promise::MaybeResolveInternal(JSContext* aCx,
JS::Handle<JS::Value> aValue,
PromiseTaskSync aAsynchronous)
{
if (mResolvePending) {
return;
}
ResolveInternal(aCx, aValue, aAsynchronous);
}
void
Promise::MaybeRejectInternal(JSContext* aCx,
JS::Handle<JS::Value> aValue,
PromiseTaskSync aAsynchronous)
{
if (mResolvePending) {
return;
}
RejectInternal(aCx, aValue, aAsynchronous);
}
void
Promise::HandleException(JSContext* aCx)
{
JS::Rooted<JS::Value> exn(aCx);
if (JS_GetPendingException(aCx, &exn)) {
JS_ClearPendingException(aCx);
RejectInternal(aCx, exn, SyncTask);
}
}
void
Promise::ResolveInternal(JSContext* aCx,
JS::Handle<JS::Value> aValue,
PromiseTaskSync aAsynchronous)
{
mResolvePending = true;
if (aValue.isObject()) {
AutoDontReportUncaught silenceReporting(aCx);
JS::Rooted<JSObject*> valueObj(aCx, &aValue.toObject());
// Thenables.
JS::Rooted<JS::Value> then(aCx);
if (!JS_GetProperty(aCx, valueObj, "then", &then)) {
HandleException(aCx);
return;
}
if (then.isObject() && JS_ObjectIsCallable(aCx, &then.toObject())) {
JS::Rooted<JSObject*> resolveFunc(aCx,
CreateThenableFunction(aCx, this, PromiseCallback::Resolve));
if (!resolveFunc) {
HandleException(aCx);
return;
}
JS::Rooted<JSObject*> rejectFunc(aCx,
CreateThenableFunction(aCx, this, PromiseCallback::Reject));
if (!rejectFunc) {
HandleException(aCx);
return;
}
LinkThenableCallables(aCx, resolveFunc, rejectFunc);
JS::Rooted<JSObject*> thenObj(aCx, &then.toObject());
nsRefPtr<PromiseInit> thenCallback =
new PromiseInit(thenObj, mozilla::dom::GetIncumbentGlobal());
ErrorResult rv;
thenCallback->Call(valueObj, resolveFunc, rejectFunc,
rv, CallbackObject::eRethrowExceptions);
rv.WouldReportJSException();
if (rv.IsJSException()) {
JS::Rooted<JS::Value> exn(aCx);
rv.StealJSException(aCx, &exn);
bool couldMarkAsCalled = MarkAsCalledIfNotCalledBefore(aCx, resolveFunc);
// If we could mark as called, neither of the callbacks had been called
// when the exception was thrown. So we can reject the Promise.
if (couldMarkAsCalled) {
bool ok = JS_WrapValue(aCx, &exn);
MOZ_ASSERT(ok);
if (!ok) {
NS_WARNING("Failed to wrap value into the right compartment.");
}
RejectInternal(aCx, exn, Promise::SyncTask);
}
// At least one of resolveFunc or rejectFunc have been called, so ignore
// the exception. FIXME(nsm): This should be reported to the error
// console though, for debugging.
}
return;
}
}
// If the synchronous flag is set, process our resolve callbacks with
// value. Otherwise, the synchronous flag is unset, queue a task to process
// own resolve callbacks with value. Otherwise, the synchronous flag is
// unset, queue a task to process our resolve callbacks with value.
RunResolveTask(aValue, Resolved, aAsynchronous);
}
void
Promise::RejectInternal(JSContext* aCx,
JS::Handle<JS::Value> aValue,
PromiseTaskSync aAsynchronous)
{
mResolvePending = true;
// If the synchronous flag is set, process our reject callbacks with
// value. Otherwise, the synchronous flag is unset, queue a task to process
// promise's reject callbacks with value.
RunResolveTask(aValue, Rejected, aAsynchronous);
}
void
Promise::RunResolveTask(JS::Handle<JS::Value> aValue,
PromiseState aState,
PromiseTaskSync aAsynchronous)
{
// If the synchronous flag is unset, queue a task to process our
// accept callbacks with value.
if (aAsynchronous == AsyncTask) {
if (MOZ_LIKELY(NS_IsMainThread())) {
nsRefPtr<PromiseResolverTask> task =
new PromiseResolverTask(this, aValue, aState);
NS_DispatchToCurrentThread(task);
} else {
WorkerPrivate* worker = GetCurrentThreadWorkerPrivate();
MOZ_ASSERT(worker);
nsRefPtr<WorkerPromiseResolverTask> task =
new WorkerPromiseResolverTask(worker, this, aValue, aState);
task->Dispatch(worker->GetJSContext());
}
return;
}
// Promise.all() or Promise.race() implementations will repeatedly call
// Resolve/RejectInternal rather than using the Maybe... forms. Stop SetState
// from asserting.
if (mState != Pending) {
return;
}
SetResult(aValue);
SetState(aState);
// If the Promise was rejected, and there is no reject handler already setup,
// watch for thread shutdown.
if (aState == PromiseState::Rejected &&
!mHadRejectCallback &&
!NS_IsMainThread()) {
WorkerPrivate* worker = GetCurrentThreadWorkerPrivate();
MOZ_ASSERT(worker);
worker->AssertIsOnWorkerThread();
mFeature = new PromiseReportRejectFeature(this);
if (NS_WARN_IF(!worker->AddFeature(worker->GetJSContext(), mFeature))) {
// Worker is shutting down, report rejection immediately since it is
// unlikely that reject callbacks will be added after this point.
MaybeReportRejected();
}
}
RunTask();
}
void
Promise::RemoveFeature()
{
if (mFeature) {
WorkerPrivate* worker = GetCurrentThreadWorkerPrivate();
MOZ_ASSERT(worker);
worker->RemoveFeature(worker->GetJSContext(), mFeature);
mFeature = nullptr;
}
}
bool
PromiseReportRejectFeature::Notify(JSContext* aCx, workers::Status aStatus)
{
MOZ_ASSERT(aStatus > workers::Running);
mPromise->MaybeReportRejectedOnce();
// After this point, `this` has been deleted by RemoveFeature!
return true;
}
// A WorkerRunnable to resolve/reject the Promise on the worker thread.
class PromiseWorkerProxyRunnable : public workers::WorkerRunnable
{
public:
PromiseWorkerProxyRunnable(PromiseWorkerProxy* aPromiseWorkerProxy,
JSStructuredCloneCallbacks* aCallbacks,
JSAutoStructuredCloneBuffer&& aBuffer,
PromiseWorkerProxy::RunCallbackFunc aFunc)
: WorkerRunnable(aPromiseWorkerProxy->GetWorkerPrivate(),
WorkerThreadUnchangedBusyCount)
, mPromiseWorkerProxy(aPromiseWorkerProxy)
, mCallbacks(aCallbacks)
, mBuffer(Move(aBuffer))
, mFunc(aFunc)
{
MOZ_ASSERT(NS_IsMainThread());
MOZ_ASSERT(mPromiseWorkerProxy);
}
virtual bool
WorkerRun(JSContext* aCx, workers::WorkerPrivate* aWorkerPrivate)
{
MOZ_ASSERT(aWorkerPrivate);
aWorkerPrivate->AssertIsOnWorkerThread();
MOZ_ASSERT(aWorkerPrivate == mWorkerPrivate);
MOZ_ASSERT(mPromiseWorkerProxy);
nsRefPtr<Promise> workerPromise = mPromiseWorkerProxy->GetWorkerPromise();
MOZ_ASSERT(workerPromise);
// Here we convert the buffer to a JS::Value.
JS::Rooted<JS::Value> value(aCx);
if (!mBuffer.read(aCx, &value, mCallbacks, mPromiseWorkerProxy)) {
JS_ClearPendingException(aCx);
return false;
}
// TODO Bug 975246 - nsRefPtr should support operator |nsRefPtr->*funcType|.
(workerPromise.get()->*mFunc)(aCx,
value,
Promise::PromiseTaskSync::SyncTask);
// Release the Promise because it has been resolved/rejected for sure.
mPromiseWorkerProxy->CleanUp(aCx);
return true;
}
protected:
~PromiseWorkerProxyRunnable() {}
private:
nsRefPtr<PromiseWorkerProxy> mPromiseWorkerProxy;
JSStructuredCloneCallbacks* mCallbacks;
JSAutoStructuredCloneBuffer mBuffer;
// Function pointer for calling Promise::{ResolveInternal,RejectInternal}.
PromiseWorkerProxy::RunCallbackFunc mFunc;
};
PromiseWorkerProxy::PromiseWorkerProxy(WorkerPrivate* aWorkerPrivate,
Promise* aWorkerPromise,
JSStructuredCloneCallbacks* aCallbacks)
: mWorkerPrivate(aWorkerPrivate)
, mWorkerPromise(aWorkerPromise)
, mCleanedUp(false)
, mCallbacks(aCallbacks)
, mCleanUpLock("cleanUpLock")
{
MOZ_ASSERT(mWorkerPrivate);
mWorkerPrivate->AssertIsOnWorkerThread();
MOZ_ASSERT(mWorkerPromise);
// We do this to make sure the worker thread won't shut down before the
// promise is resolved/rejected on the worker thread.
if (!mWorkerPrivate->AddFeature(mWorkerPrivate->GetJSContext(), this)) {
MOZ_ASSERT(false, "cannot add the worker feature!");
return;
}
}
PromiseWorkerProxy::~PromiseWorkerProxy()
{
MOZ_ASSERT(mCleanedUp);
MOZ_ASSERT(!mWorkerPromise);
}
WorkerPrivate*
PromiseWorkerProxy::GetWorkerPrivate() const
{
// It's ok to race on |mCleanedUp|, because it will never cause us to fire
// the assertion when we should not.
MOZ_ASSERT(!mCleanedUp);
return mWorkerPrivate;
}
Promise*
PromiseWorkerProxy::GetWorkerPromise() const
{
return mWorkerPromise;
}
void
PromiseWorkerProxy::StoreISupports(nsISupports* aSupports)
{
MOZ_ASSERT(NS_IsMainThread());
nsMainThreadPtrHandle<nsISupports> supports =
new nsMainThreadPtrHolder<nsISupports>(aSupports);
mSupportsArray.AppendElement(supports);
}
void
PromiseWorkerProxy::RunCallback(JSContext* aCx,
JS::Handle<JS::Value> aValue,
RunCallbackFunc aFunc)
{
MOZ_ASSERT(NS_IsMainThread());
MutexAutoLock lock(mCleanUpLock);
// If the worker thread's been cancelled we don't need to resolve the Promise.
if (mCleanedUp) {
return;
}
// The |aValue| is written into the buffer. Note that we also pass |this|
// into the structured-clone write in order to set its |mSupportsArray| to
// keep objects alive until the structured-clone read/write is done.
JSAutoStructuredCloneBuffer buffer;
if (!buffer.write(aCx, aValue, mCallbacks, this)) {
JS_ClearPendingException(aCx);
MOZ_ASSERT(false, "cannot write the JSAutoStructuredCloneBuffer!");
}
nsRefPtr<PromiseWorkerProxyRunnable> runnable =
new PromiseWorkerProxyRunnable(this,
mCallbacks,
Move(buffer),
aFunc);
runnable->Dispatch(aCx);
}
void
PromiseWorkerProxy::ResolvedCallback(JSContext* aCx,
JS::Handle<JS::Value> aValue)
{
RunCallback(aCx, aValue, &Promise::ResolveInternal);
}
void
PromiseWorkerProxy::RejectedCallback(JSContext* aCx,
JS::Handle<JS::Value> aValue)
{
RunCallback(aCx, aValue, &Promise::RejectInternal);
}
bool
PromiseWorkerProxy::Notify(JSContext* aCx, Status aStatus)
{
MOZ_ASSERT(mWorkerPrivate);
mWorkerPrivate->AssertIsOnWorkerThread();
MOZ_ASSERT(mWorkerPrivate->GetJSContext() == aCx);
if (aStatus >= Canceling) {
CleanUp(aCx);
}
return true;
}
void
PromiseWorkerProxy::CleanUp(JSContext* aCx)
{
MutexAutoLock lock(mCleanUpLock);
// |mWorkerPrivate| might not be safe to use anymore if we have already
// cleaned up and RemoveFeature(), so we need to check |mCleanedUp| first.
if (mCleanedUp) {
return;
}
MOZ_ASSERT(mWorkerPrivate);
mWorkerPrivate->AssertIsOnWorkerThread();
MOZ_ASSERT(mWorkerPrivate->GetJSContext() == aCx);
// Release the Promise and remove the PromiseWorkerProxy from the features of
// the worker thread since the Promise has been resolved/rejected or the
// worker thread has been cancelled.
mWorkerPromise = nullptr;
mWorkerPrivate->RemoveFeature(aCx, this);
mCleanedUp = true;
}
} // namespace dom
} // namespace mozilla
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