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/BindingUtils.h"
#include "mozilla/dom/DOMError.h"
#include "mozilla/dom/OwningNonNull.h"
#include "mozilla/dom/PromiseBinding.h"
#include "mozilla/dom/ScriptSettings.h"
#include "mozilla/dom/MediaStreamError.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"
#include "nsIScriptObjectPrincipal.h"
#include "xpcpublic.h"
#include "nsGlobalWindow.h"
namespace mozilla {
namespace dom {
using namespace workers;
NS_IMPL_ISUPPORTS0(PromiseNativeHandler)
// This class processes the promise's callbacks with promise's result.
class PromiseCallbackTask MOZ_FINAL : public nsRunnable
{
public:
PromiseCallbackTask(Promise* aPromise,
PromiseCallback* aCallback,
const JS::Value& aValue)
: mPromise(aPromise)
, mCallback(aCallback)
, mValue(CycleCollectedJSRuntime::Get()->Runtime(), aValue)
{
MOZ_ASSERT(aPromise);
MOZ_ASSERT(aCallback);
MOZ_COUNT_CTOR(PromiseCallbackTask);
}
virtual
~PromiseCallbackTask()
{
NS_ASSERT_OWNINGTHREAD(PromiseCallbackTask);
MOZ_COUNT_DTOR(PromiseCallbackTask);
}
protected:
NS_IMETHOD
Run() MOZ_OVERRIDE
{
NS_ASSERT_OWNINGTHREAD(PromiseCallbackTask);
ThreadsafeAutoJSContext cx;
JS::Rooted<JSObject*> wrapper(cx, mPromise->GetWrapper());
MOZ_ASSERT(wrapper); // It was preserved!
JSAutoCompartment ac(cx, wrapper);
JS::Rooted<JS::Value> value(cx, mValue);
if (!MaybeWrapValue(cx, &value)) {
NS_WARNING("Failed to wrap value into the right compartment.");
JS_ClearPendingException(cx);
return NS_OK;
}
mCallback->Call(cx, value);
return NS_OK;
}
private:
nsRefPtr<Promise> mPromise;
nsRefPtr<PromiseCallback> mCallback;
JS::PersistentRooted<JS::Value> mValue;
NS_DECL_OWNINGTHREAD;
};
enum {
SLOT_PROMISE = 0,
SLOT_DATA
};
/*
* 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;
}
};
// Main thread runnable to resolve thenables.
// Equivalent to the specification's ResolvePromiseViaThenableTask.
class ThenableResolverTask MOZ_FINAL : public nsRunnable
{
public:
ThenableResolverTask(Promise* aPromise,
JS::Handle<JSObject*> aThenable,
PromiseInit* aThen)
: mPromise(aPromise)
, mThenable(CycleCollectedJSRuntime::Get()->Runtime(), aThenable)
, mThen(aThen)
{
MOZ_ASSERT(aPromise);
MOZ_COUNT_CTOR(ThenableResolverTask);
}
virtual
~ThenableResolverTask()
{
NS_ASSERT_OWNINGTHREAD(ThenableResolverTask);
MOZ_COUNT_DTOR(ThenableResolverTask);
}
protected:
NS_IMETHOD
Run() MOZ_OVERRIDE
{
NS_ASSERT_OWNINGTHREAD(ThenableResolverTask);
ThreadsafeAutoJSContext cx;
JS::Rooted<JSObject*> wrapper(cx, mPromise->GetWrapper());
MOZ_ASSERT(wrapper); // It was preserved!
JSAutoCompartment ac(cx, wrapper);
JS::Rooted<JSObject*> resolveFunc(cx,
mPromise->CreateThenableFunction(cx, mPromise, PromiseCallback::Resolve));
if (!resolveFunc) {
mPromise->HandleException(cx);
return NS_OK;
}
JS::Rooted<JSObject*> rejectFunc(cx,
mPromise->CreateThenableFunction(cx, mPromise, PromiseCallback::Reject));
if (!rejectFunc) {
mPromise->HandleException(cx);
return NS_OK;
}
LinkThenableCallables(cx, resolveFunc, rejectFunc);
ErrorResult rv;
JS::Rooted<JSObject*> rootedThenable(cx, mThenable);
mThen->Call(rootedThenable, resolveFunc, rejectFunc, rv,
CallbackObject::eRethrowExceptions);
rv.WouldReportJSException();
if (rv.IsJSException()) {
JS::Rooted<JS::Value> exn(cx);
rv.StealJSException(cx, &exn);
bool couldMarkAsCalled = MarkAsCalledIfNotCalledBefore(cx, 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(cx, &exn);
MOZ_ASSERT(ok);
if (!ok) {
NS_WARNING("Failed to wrap value into the right compartment.");
}
mPromise->RejectInternal(cx, exn);
}
// 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 NS_OK;
}
private:
nsRefPtr<Promise> mPromise;
JS::PersistentRooted<JSObject*> mThenable;
nsRefPtr<PromiseInit> mThen;
NS_DECL_OWNINGTHREAD;
};
// 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_JS_MEMBER_CALLBACK(mAllocationStack)
NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mRejectionStack)
NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mFullfillmentStack)
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())
, mAllocationStack(nullptr)
, mRejectionStack(nullptr)
, mFullfillmentStack(nullptr)
, mState(Pending)
, mHadRejectCallback(false)
, mResolvePending(false)
{
MOZ_ASSERT(mGlobal);
mozilla::HoldJSObjects(this);
mCreationTimestamp = TimeStamp::Now();
}
Promise::~Promise()
{
MaybeReportRejectedOnce();
mozilla::DropJSObjects(this);
}
JSObject*
Promise::WrapObject(JSContext* aCx)
{
return PromiseBinding::Wrap(aCx, this);
}
already_AddRefed<Promise>
Promise::Create(nsIGlobalObject* aGlobal, ErrorResult& aRv)
{
nsRefPtr<Promise> p = new Promise(aGlobal);
p->CreateWrapper(aRv);
if (aRv.Failed()) {
return nullptr;
}
return p.forget();
}
void
Promise::CreateWrapper(ErrorResult& aRv)
{
AutoJSAPI jsapi;
if (!jsapi.Init(mGlobal)) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return;
}
JSContext* cx = jsapi.cx();
JS::Rooted<JS::Value> ignored(cx);
if (!WrapNewBindingObject(cx, this, &ignored)) {
JS_ClearPendingException(cx);
aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
dom::PreserveWrapper(this);
// Now grab our allocation stack
if (!CaptureStack(cx, mAllocationStack)) {
JS_ClearPendingException(cx);
aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
}
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);
}
void
Promise::MaybeReject(const nsRefPtr<MediaStreamError>& aArg) {
MaybeSomething(aArg, &Promise::MaybeReject);
}
bool
Promise::PerformMicroTaskCheckpoint()
{
CycleCollectedJSRuntime* runtime = CycleCollectedJSRuntime::Get();
nsTArray<nsRefPtr<nsIRunnable>>& microtaskQueue =
runtime->GetPromiseMicroTaskQueue();
if (microtaskQueue.IsEmpty()) {
return false;
}
do {
nsRefPtr<nsIRunnable> runnable = microtaskQueue.ElementAt(0);
MOZ_ASSERT(runnable);
// This function can re-enter, so we remove the element before calling.
microtaskQueue.RemoveElementAt(0);
runnable->Run();
} while (!microtaskQueue.IsEmpty());
return true;
}
/* 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));
if (!promise->CaptureStack(aCx, promise->mFullfillmentStack)) {
return false;
}
} else {
promise->MaybeRejectInternal(aCx, args.get(0));
if (!promise->CaptureStack(aCx, promise->mRejectionStack)) {
return false;
}
}
return true;
}
/*
* 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));
} else {
promise->RejectInternal(aCx, args.get(0));
}
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)
{
nsCOMPtr<nsIGlobalObject> global;
global = do_QueryInterface(aGlobal.GetAsSupports());
if (!global) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
nsRefPtr<Promise> promise = Create(global, aRv);
if (aRv.Failed()) {
return nullptr;
}
promise->CallInitFunction(aGlobal, aInit, aRv);
if (aRv.Failed()) {
return nullptr;
}
return promise.forget();
}
void
Promise::CallInitFunction(const GlobalObject& aGlobal,
PromiseInit& aInit, ErrorResult& aRv)
{
JSContext* cx = aGlobal.Context();
JS::Rooted<JSObject*> resolveFunc(cx,
CreateFunction(cx, aGlobal.Get(), this,
PromiseCallback::Resolve));
if (!resolveFunc) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return;
}
JS::Rooted<JSObject*> rejectFunc(cx,
CreateFunction(cx, aGlobal.Get(), this,
PromiseCallback::Reject));
if (!rejectFunc) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return;
}
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;
}
MaybeRejectInternal(cx, value);
}
}
/* static */ already_AddRefed<Promise>
Promise::Resolve(const GlobalObject& aGlobal,
JS::Handle<JS::Value> aValue, ErrorResult& aRv)
{
// If a Promise was passed, just return it.
if (aValue.isObject()) {
JS::Rooted<JSObject*> valueObj(aGlobal.Context(), &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;
}
nsRefPtr<Promise> p = Resolve(global, aGlobal.Context(), aValue, aRv);
if (p) {
p->mFullfillmentStack = p->mAllocationStack;
}
return p.forget();
}
/* static */ already_AddRefed<Promise>
Promise::Resolve(nsIGlobalObject* aGlobal, JSContext* aCx,
JS::Handle<JS::Value> aValue, ErrorResult& aRv)
{
nsRefPtr<Promise> promise = Create(aGlobal, aRv);
if (aRv.Failed()) {
return nullptr;
}
promise->MaybeResolveInternal(aCx, aValue);
return promise.forget();
}
/* static */ already_AddRefed<Promise>
Promise::Reject(const GlobalObject& aGlobal,
JS::Handle<JS::Value> aValue, ErrorResult& aRv)
{
nsCOMPtr<nsIGlobalObject> global =
do_QueryInterface(aGlobal.GetAsSupports());
if (!global) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
nsRefPtr<Promise> p = Reject(global, aGlobal.Context(), aValue, aRv);
if (p) {
p->mRejectionStack = p->mAllocationStack;
}
return p.forget();
}
/* static */ already_AddRefed<Promise>
Promise::Reject(nsIGlobalObject* aGlobal, JSContext* aCx,
JS::Handle<JS::Value> aValue, ErrorResult& aRv)
{
nsRefPtr<Promise> promise = Create(aGlobal, aRv);
if (aRv.Failed()) {
return nullptr;
}
promise->MaybeRejectInternal(aCx, aValue);
return promise.forget();
}
already_AddRefed<Promise>
Promise::Then(JSContext* aCx, AnyCallback* aResolveCallback,
AnyCallback* aRejectCallback, ErrorResult& aRv)
{
nsRefPtr<Promise> promise = Create(GetParentObject(), aRv);
if (aRv.Failed()) {
return nullptr;
}
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, ErrorResult& aRv)
{
nsRefPtr<AnyCallback> resolveCb;
return Then(aCx, resolveCb, aRejectCallback, aRv);
}
/**
* 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.Context();
// The only time aGlobal.Context() 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);
}
private:
~CountdownHolder()
{
mozilla::DropJSObjects(this);
}
public:
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);
}
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:
~AllResolveHandler()
{
}
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,
const Sequence<JS::Value>& aIterable, ErrorResult& aRv)
{
nsCOMPtr<nsIGlobalObject> global =
do_QueryInterface(aGlobal.GetAsSupports());
if (!global) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
JSContext* cx = aGlobal.Context();
if (aIterable.Length() == 0) {
JS::Rooted<JSObject*> empty(cx, JS_NewArrayObject(cx, 0));
if (!empty) {
aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
return nullptr;
}
JS::Rooted<JS::Value> value(cx, JS::ObjectValue(*empty));
// We know "value" is not a promise, so call the Resolve function
// that doesn't have to check for that.
return Promise::Resolve(global, cx, value, aRv);
}
nsRefPtr<Promise> promise = Create(global, aRv);
if (aRv.Failed()) {
return nullptr;
}
nsRefPtr<CountdownHolder> holder =
new CountdownHolder(aGlobal, promise, aIterable.Length());
JS::Rooted<JSObject*> obj(cx, JS::CurrentGlobalOrNull(cx));
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(cx, aIterable.ElementAt(i));
nsRefPtr<Promise> nextPromise = Promise::Resolve(aGlobal, 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,
const Sequence<JS::Value>& aIterable, ErrorResult& aRv)
{
nsCOMPtr<nsIGlobalObject> global =
do_QueryInterface(aGlobal.GetAsSupports());
if (!global) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
JSContext* cx = aGlobal.Context();
JS::Rooted<JSObject*> obj(cx, JS::CurrentGlobalOrNull(cx));
if (!obj) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
nsRefPtr<Promise> promise = Create(global, aRv);
if (aRv.Failed()) {
return nullptr;
}
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(cx, aIterable.ElementAt(i));
nsRefPtr<Promise> nextPromise = Promise::Resolve(aGlobal, 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 fulfilled, queue a task to process our fulfill
// 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) {
EnqueueCallbackTasks();
}
}
class WrappedWorkerRunnable MOZ_FINAL : public WorkerSameThreadRunnable
{
public:
WrappedWorkerRunnable(WorkerPrivate* aWorkerPrivate, nsIRunnable* aRunnable)
: WorkerSameThreadRunnable(aWorkerPrivate)
, mRunnable(aRunnable)
{
MOZ_ASSERT(aRunnable);
MOZ_COUNT_CTOR(WrappedWorkerRunnable);
}
bool
WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
{
NS_ASSERT_OWNINGTHREAD(WrappedWorkerRunnable);
mRunnable->Run();
return true;
}
private:
virtual
~WrappedWorkerRunnable()
{
MOZ_COUNT_DTOR(WrappedWorkerRunnable);
NS_ASSERT_OWNINGTHREAD(WrappedWorkerRunnable);
}
nsCOMPtr<nsIRunnable> mRunnable;
NS_DECL_OWNINGTHREAD
};
/* static */ void
Promise::DispatchToMicroTask(nsIRunnable* aRunnable)
{
MOZ_ASSERT(aRunnable);
CycleCollectedJSRuntime* runtime = CycleCollectedJSRuntime::Get();
nsTArray<nsRefPtr<nsIRunnable>>& microtaskQueue =
runtime->GetPromiseMicroTaskQueue();
microtaskQueue.AppendElement(aRunnable);
}
void
Promise::MaybeReportRejected()
{
if (mState != Rejected || mHadRejectCallback || mResult.isUndefined()) {
return;
}
AutoJSAPI jsapi;
// We may not have a usable global by now (if it got unlinked
// already), so don't init with it.
jsapi.Init();
JSContext* cx = jsapi.cx();
JS::Rooted<JSObject*> obj(cx, GetWrapper());
MOZ_ASSERT(obj); // We preserve our wrapper, so should always have one here.
JS::Rooted<JS::Value> val(cx, mResult);
JS::ExposeValueToActiveJS(val);
JSAutoCompartment ac(cx, obj);
if (!JS_WrapValue(cx, &val)) {
JS_ClearPendingException(cx);
return;
}
js::ErrorReport report(cx);
if (!report.init(cx, val)) {
JS_ClearPendingException(cx);
return;
}
nsRefPtr<xpc::ErrorReport> xpcReport = new xpc::ErrorReport();
bool isMainThread = MOZ_LIKELY(NS_IsMainThread());
bool isChrome = isMainThread ? nsContentUtils::IsSystemPrincipal(nsContentUtils::ObjectPrincipal(obj))
: GetCurrentThreadWorkerPrivate()->IsChromeWorker();
nsPIDOMWindow* win = isMainThread ? xpc::WindowGlobalOrNull(obj) : nullptr;
xpcReport->Init(report.report(), report.message(), isChrome, win ? win->WindowID() : 0);
// 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(CycleCollectedJSRuntime::Get()->Runtime(), xpcReport);
NS_DispatchToMainThread(r);
}
void
Promise::MaybeResolveInternal(JSContext* aCx,
JS::Handle<JS::Value> aValue)
{
if (mResolvePending) {
return;
}
ResolveInternal(aCx, aValue);
}
void
Promise::MaybeRejectInternal(JSContext* aCx,
JS::Handle<JS::Value> aValue)
{
if (mResolvePending) {
return;
}
RejectInternal(aCx, aValue);
}
void
Promise::HandleException(JSContext* aCx)
{
JS::Rooted<JS::Value> exn(aCx);
if (JS_GetPendingException(aCx, &exn)) {
JS_ClearPendingException(aCx);
RejectInternal(aCx, exn);
}
}
void
Promise::ResolveInternal(JSContext* aCx,
JS::Handle<JS::Value> aValue)
{
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::IsCallable(&then.toObject())) {
// This is the then() function of the thenable aValueObj.
JS::Rooted<JSObject*> thenObj(aCx, &then.toObject());
nsRefPtr<PromiseInit> thenCallback =
new PromiseInit(thenObj, mozilla::dom::GetIncumbentGlobal());
nsRefPtr<ThenableResolverTask> task =
new ThenableResolverTask(this, valueObj, thenCallback);
DispatchToMicroTask(task);
return;
}
}
MaybeSettle(aValue, Resolved);
}
void
Promise::RejectInternal(JSContext* aCx,
JS::Handle<JS::Value> aValue)
{
mResolvePending = true;
MaybeSettle(aValue, Rejected);
}
void
Promise::MaybeSettle(JS::Handle<JS::Value> aValue,
PromiseState aState)
{
// 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);
mSettlementTimestamp = TimeStamp::Now();
// 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))) {
// To avoid a false RemoveFeature().
mFeature = nullptr;
// Worker is shutting down, report rejection immediately since it is
// unlikely that reject callbacks will be added after this point.
MaybeReportRejectedOnce();
}
}
EnqueueCallbackTasks();
}
void
Promise::EnqueueCallbackTasks()
{
nsTArray<nsRefPtr<PromiseCallback>> callbacks;
callbacks.SwapElements(mState == Resolved ? mResolveCallbacks
: mRejectCallbacks);
mResolveCallbacks.Clear();
mRejectCallbacks.Clear();
for (uint32_t i = 0; i < callbacks.Length(); ++i) {
nsRefPtr<PromiseCallbackTask> task =
new PromiseCallbackTask(this, callbacks[i], mResult);
DispatchToMicroTask(task);
}
}
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;
}
bool
Promise::CaptureStack(JSContext* aCx, JS::Heap<JSObject*>& aTarget)
{
JS::Rooted<JSObject*> stack(aCx);
if (!JS::CaptureCurrentStack(aCx, &stack)) {
return false;
}
aTarget = stack;
return true;
}
void
Promise::GetDependentPromises(nsTArray<nsRefPtr<Promise>>& aPromises)
{
// We want to return promises that correspond to then() calls, Promise.all()
// calls, and Promise.race() calls.
//
// For the then() case, we have both resolve and reject callbacks that know
// what the next promise is.
//
// For the race() case, likewise.
//
// For the all() case, our reject callback knows what the next promise is, but
// our resolve callback just knows it needs to notify some
// PromiseNativeHandler, which itself only has an indirect relationship to the
// next promise.
//
// So we walk over our _reject_ callbacks and ask each of them what promise
// its dependent promise is.
for (size_t i = 0; i < mRejectCallbacks.Length(); ++i) {
Promise* p = mRejectCallbacks[i]->GetDependentPromise();
if (p) {
aPromises.AppendElement(p);
}
}
}
// 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);
// 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;
}
// Specializations of MaybeRejectBrokenly we actually support.
template<>
void Promise::MaybeRejectBrokenly(const nsRefPtr<DOMError>& aArg) {
MaybeSomething(aArg, &Promise::MaybeReject);
}
template<>
void Promise::MaybeRejectBrokenly(const nsAString& aArg) {
MaybeSomething(aArg, &Promise::MaybeReject);
}
} // namespace dom
} // namespace mozilla