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/Preferences.h"
#include "PromiseCallback.h"
#include "nsContentUtils.h"
#include "nsPIDOMWindow.h"
#include "WorkerPrivate.h"
#include "nsJSPrincipals.h"
#include "nsJSUtils.h"
#include "nsPIDOMWindow.h"
#include "nsJSEnvironment.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;
};
// This class processes the promise's callbacks with promise's result.
class PromiseResolverTask MOZ_FINAL : public nsRunnable
{
public:
PromiseResolverTask(Promise* aPromise,
JS::Handle<JS::Value> aValue,
Promise::PromiseState aState)
: mPromise(aPromise)
, mValue(aValue)
, mState(aState)
{
MOZ_ASSERT(aPromise);
MOZ_ASSERT(mState != Promise::Pending);
MOZ_COUNT_CTOR(PromiseResolverTask);
JSContext* cx = nsContentUtils::GetSafeJSContext();
/* It's safe to use unsafeGet() here: the unsafeness comes from the
* possibility of updating the value of mJSObject without triggering the
* barriers. However if the value will always be marked, post barriers
* unnecessary. */
JS_AddNamedValueRootRT(JS_GetRuntime(cx), mValue.unsafeGet(),
"PromiseResolverTask.mValue");
}
~PromiseResolverTask()
{
MOZ_COUNT_DTOR(PromiseResolverTask);
JSContext* cx = nsContentUtils::GetSafeJSContext();
/* It's safe to use unsafeGet() here: the unsafeness comes from the
* possibility of updating the value of mJSObject without triggering the
* barriers. However if the value will always be marked, post barriers
* unnecessary. */
JS_RemoveValueRootRT(JS_GetRuntime(cx), mValue.unsafeGet());
}
NS_IMETHOD Run()
{
mPromise->RunResolveTask(
JS::Handle<JS::Value>::fromMarkedLocation(mValue.address()),
mState, Promise::SyncTask);
return NS_OK;
}
private:
nsRefPtr<Promise> mPromise;
JS::Heap<JS::Value> mValue;
Promise::PromiseState mState;
};
// Promise
NS_IMPL_CYCLE_COLLECTION_CLASS(Promise)
NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(Promise)
tmp->MaybeReportRejected();
NS_IMPL_CYCLE_COLLECTION_UNLINK(mWindow)
NS_IMPL_CYCLE_COLLECTION_UNLINK(mResolveCallbacks);
NS_IMPL_CYCLE_COLLECTION_UNLINK(mRejectCallbacks);
tmp->mResult = JS::UndefinedValue();
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(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)
, mHadRejectCallback(false)
, mResolvePending(false)
{
MOZ_COUNT_CTOR(Promise);
mozilla::HoldJSObjects(this);
SetIsDOMBinding();
}
Promise::~Promise()
{
MaybeReportRejected();
mResult = JS::UndefinedValue();
mozilla::DropJSObjects(this);
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 */ bool
Promise::EnabledForScope(JSContext* aCx, JSObject* /* unused */)
{
// Enable if the pref is enabled or if we're chrome or if we're a
// certified app.
if (PrefEnabled()) {
return true;
}
// Note that we have no concept of a certified app in workers.
// XXXbz well, why not?
if (!NS_IsMainThread()) {
return workers::GetWorkerPrivateFromContext(aCx)->IsChromeWorker();
}
nsIPrincipal* prin = nsContentUtils::GetSubjectPrincipal();
return nsContentUtils::IsSystemPrincipal(prin) ||
prin->GetAppStatus() == nsIPrincipal::APP_STATUS_CERTIFIED;
}
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);
}
}
enum {
SLOT_PROMISE = 0,
SLOT_TASK
};
/* 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, aCx, &v.toObject(), promise))) {
return Throw(aCx, NS_ERROR_UNEXPECTED);
}
Optional<JS::Handle<JS::Value> > value(aCx);
if (aArgc) {
value.Value() = args[0];
}
v = js::GetFunctionNativeReserved(&args.callee(), SLOT_TASK);
PromiseCallback::Task task = static_cast<PromiseCallback::Task>(v.toInt32());
if (task == PromiseCallback::Resolve) {
promise->MaybeResolve(aCx, value);
} else {
promise->MaybeReject(aCx, value);
}
return true;
}
/* 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, obj, aPromise, &promiseObj)) {
return nullptr;
}
js::SetFunctionNativeReserved(obj, SLOT_PROMISE, promiseObj);
js::SetFunctionNativeReserved(obj, SLOT_TASK, JS::Int32Value(aTask));
return obj;
}
/* static */ already_AddRefed<Promise>
Promise::Constructor(const GlobalObject& aGlobal,
PromiseInit& aInit, ErrorResult& aRv)
{
JSContext* cx = aGlobal.GetContext();
nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(aGlobal.GetAsSupports());
if (!window) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
nsRefPtr<Promise> promise = new Promise(window);
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(promise, resolveFunc, rejectFunc, aRv,
CallbackObject::eRethrowExceptions);
aRv.WouldReportJSException();
if (aRv.IsJSException()) {
Optional<JS::Handle<JS::Value> > value(cx);
aRv.StealJSException(cx, &value.Value());
Maybe<JSAutoCompartment> ac;
EnterCompartment(ac, cx, value);
promise->MaybeReject(cx, value);
}
return promise.forget();
}
/* static */ already_AddRefed<Promise>
Promise::Resolve(const GlobalObject& aGlobal, JSContext* aCx,
JS::Handle<JS::Value> aValue, ErrorResult& aRv)
{
nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(aGlobal.GetAsSupports());
if (!window) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
nsRefPtr<Promise> promise = new Promise(window);
Optional<JS::Handle<JS::Value> > value(aCx, aValue);
promise->MaybeResolve(aCx, value);
return promise.forget();
}
/* static */ already_AddRefed<Promise>
Promise::Reject(const GlobalObject& aGlobal, JSContext* aCx,
JS::Handle<JS::Value> aValue, ErrorResult& aRv)
{
nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(aGlobal.GetAsSupports());
if (!window) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
nsRefPtr<Promise> promise = new Promise(window);
Optional<JS::Handle<JS::Value> > value(aCx, aValue);
promise->MaybeReject(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,
aResolveCallback.WasPassed()
? &aResolveCallback.Value()
: nullptr,
PromiseCallback::Resolve);
nsRefPtr<PromiseCallback> rejectCb =
PromiseCallback::Factory(promise,
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) {
mHadRejectCallback = true;
mRejectCallbacks.AppendElement(aRejectCallback);
}
// 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) {
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);
}
}
void
Promise::MaybeReportRejected()
{
if (mState != Rejected || mHadRejectCallback || mResult.isUndefined()) {
return;
}
JSErrorReport* report = js::ErrorFromException(mResult);
if (!report) {
return;
}
MOZ_ASSERT(mResult.isObject(), "How did we get a JSErrorReport?");
nsCOMPtr<nsPIDOMWindow> win =
do_QueryInterface(nsJSUtils::GetStaticScriptGlobal(&mResult.toObject()));
// Now post an event to do the real reporting async
NS_DispatchToCurrentThread(
new AsyncErrorReporter(JS_GetObjectRuntime(&mResult.toObject()),
report,
nullptr,
nsContentUtils::GetObjectPrincipal(&mResult.toObject()),
win));
}
void
Promise::MaybeResolve(JSContext* aCx,
const Optional<JS::Handle<JS::Value> >& aValue,
PromiseTaskSync aAsynchronous)
{
if (mResolvePending) {
return;
}
ResolveInternal(aCx, aValue, aAsynchronous);
}
void
Promise::MaybeReject(JSContext* aCx,
const Optional<JS::Handle<JS::Value> >& aValue,
PromiseTaskSync aAsynchronous)
{
if (mResolvePending) {
return;
}
RejectInternal(aCx, aValue, aAsynchronous);
}
void
Promise::ResolveInternal(JSContext* aCx,
const Optional<JS::Handle<JS::Value> >& aValue,
PromiseTaskSync aAsynchronous)
{
mResolvePending = true;
// TODO: Bug 879245 - Then-able objects
if (aValue.WasPassed() && aValue.Value().isObject()) {
JS::Rooted<JSObject*> valueObj(aCx, &aValue.Value().toObject());
Promise* nextPromise;
nsresult rv = UNWRAP_OBJECT(Promise, aCx, valueObj, nextPromise);
if (NS_SUCCEEDED(rv)) {
nsRefPtr<PromiseCallback> resolveCb = new ResolvePromiseCallback(this);
nsRefPtr<PromiseCallback> rejectCb = new RejectPromiseCallback(this);
nextPromise->AppendCallbacks(resolveCb, rejectCb);
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.WasPassed() ? aValue.Value() : JS::UndefinedHandleValue,
Resolved, aAsynchronous);
}
void
Promise::RejectInternal(JSContext* aCx,
const Optional<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.WasPassed() ? aValue.Value() : JS::UndefinedHandleValue,
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) {
nsRefPtr<PromiseResolverTask> task =
new PromiseResolverTask(this, aValue, aState);
NS_DispatchToCurrentThread(task);
return;
}
SetResult(aValue);
SetState(aState);
RunTask();
}
} // namespace dom
} // namespace mozilla