gecko-dev/dom/promise/PromiseDebugging.cpp
2015-05-03 15:32:37 -04:00

282 lines
8.1 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=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 "js/Value.h"
#include "nsThreadUtils.h"
#include "mozilla/CycleCollectedJSRuntime.h"
#include "mozilla/ThreadLocal.h"
#include "mozilla/TimeStamp.h"
#include "mozilla/dom/BindingDeclarations.h"
#include "mozilla/dom/ContentChild.h"
#include "mozilla/dom/Promise.h"
#include "mozilla/dom/PromiseDebugging.h"
#include "mozilla/dom/PromiseDebuggingBinding.h"
namespace mozilla {
namespace dom {
class FlushRejections: public nsCancelableRunnable
{
public:
static void Init() {
if (!sDispatched.init()) {
MOZ_CRASH("Could not initialize FlushRejections::sDispatched");
}
sDispatched.set(false);
}
static void DispatchNeeded() {
if (sDispatched.get()) {
// An instance of `FlushRejections` has already been dispatched
// and not run yet. No need to dispatch another one.
return;
}
sDispatched.set(true);
NS_DispatchToCurrentThread(new FlushRejections());
}
static void FlushSync() {
sDispatched.set(false);
// Call the callbacks if necessary.
// Note that these callbacks may in turn cause Promise to turn
// uncaught or consumed. Since `sDispatched` is `false`,
// `FlushRejections` will be called once again, on an ulterior
// tick.
PromiseDebugging::FlushUncaughtRejectionsInternal();
}
NS_IMETHOD Run() {
FlushSync();
return NS_OK;
}
private:
// `true` if an instance of `FlushRejections` is currently dispatched
// and has not been executed yet.
static ThreadLocal<bool> sDispatched;
};
/* static */ ThreadLocal<bool>
FlushRejections::sDispatched;
/* static */ void
PromiseDebugging::GetState(GlobalObject&, Promise& aPromise,
PromiseDebuggingStateHolder& aState)
{
switch (aPromise.mState) {
case Promise::Pending:
aState.mState = PromiseDebuggingState::Pending;
break;
case Promise::Resolved:
aState.mState = PromiseDebuggingState::Fulfilled;
JS::ExposeValueToActiveJS(aPromise.mResult);
aState.mValue = aPromise.mResult;
break;
case Promise::Rejected:
aState.mState = PromiseDebuggingState::Rejected;
JS::ExposeValueToActiveJS(aPromise.mResult);
aState.mReason = aPromise.mResult;
break;
}
}
/*static */ nsString
PromiseDebugging::sIDPrefix;
/* static */ void
PromiseDebugging::Init()
{
FlushRejections::Init();
// Generate a prefix for identifiers: "PromiseDebugging.$processid."
sIDPrefix = NS_LITERAL_STRING("PromiseDebugging.");
if (XRE_GetProcessType() == GeckoProcessType_Content) {
sIDPrefix.AppendInt(ContentChild::GetSingleton()->GetID());
sIDPrefix.Append('.');
} else {
sIDPrefix.AppendLiteral("0.");
}
}
/* static */ void
PromiseDebugging::Shutdown()
{
sIDPrefix.SetIsVoid(true);
}
/* static */ void
PromiseDebugging::FlushUncaughtRejections()
{
MOZ_ASSERT(!NS_IsMainThread());
FlushRejections::FlushSync();
}
/* static */ void
PromiseDebugging::GetAllocationStack(GlobalObject&, Promise& aPromise,
JS::MutableHandle<JSObject*> aStack)
{
aStack.set(aPromise.mAllocationStack);
}
/* static */ void
PromiseDebugging::GetRejectionStack(GlobalObject&, Promise& aPromise,
JS::MutableHandle<JSObject*> aStack)
{
aStack.set(aPromise.mRejectionStack);
}
/* static */ void
PromiseDebugging::GetFullfillmentStack(GlobalObject&, Promise& aPromise,
JS::MutableHandle<JSObject*> aStack)
{
aStack.set(aPromise.mFullfillmentStack);
}
/* static */ void
PromiseDebugging::GetDependentPromises(GlobalObject&, Promise& aPromise,
nsTArray<nsRefPtr<Promise>>& aPromises)
{
aPromise.GetDependentPromises(aPromises);
}
/* static */ double
PromiseDebugging::GetPromiseLifetime(GlobalObject&, Promise& aPromise)
{
return (TimeStamp::Now() - aPromise.mCreationTimestamp).ToMilliseconds();
}
/* static */ double
PromiseDebugging::GetTimeToSettle(GlobalObject&, Promise& aPromise,
ErrorResult& aRv)
{
if (aPromise.mState == Promise::Pending) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return 0;
}
return (aPromise.mSettlementTimestamp -
aPromise.mCreationTimestamp).ToMilliseconds();
}
/* static */ void
PromiseDebugging::AddUncaughtRejectionObserver(GlobalObject&,
UncaughtRejectionObserver& aObserver)
{
CycleCollectedJSRuntime* storage = CycleCollectedJSRuntime::Get();
nsTArray<nsCOMPtr<nsISupports>>& observers = storage->mUncaughtRejectionObservers;
observers.AppendElement(&aObserver);
}
/* static */ bool
PromiseDebugging::RemoveUncaughtRejectionObserver(GlobalObject&,
UncaughtRejectionObserver& aObserver)
{
CycleCollectedJSRuntime* storage = CycleCollectedJSRuntime::Get();
nsTArray<nsCOMPtr<nsISupports>>& observers = storage->mUncaughtRejectionObservers;
for (size_t i = 0; i < observers.Length(); ++i) {
UncaughtRejectionObserver* observer = static_cast<UncaughtRejectionObserver*>(observers[i].get());
if (*observer == aObserver) {
observers.RemoveElementAt(i);
return true;
}
}
return false;
}
/* static */ void
PromiseDebugging::AddUncaughtRejection(Promise& aPromise)
{
CycleCollectedJSRuntime::Get()->mUncaughtRejections.AppendElement(&aPromise);
FlushRejections::DispatchNeeded();
}
/* void */ void
PromiseDebugging::AddConsumedRejection(Promise& aPromise)
{
CycleCollectedJSRuntime::Get()->mConsumedRejections.AppendElement(&aPromise);
FlushRejections::DispatchNeeded();
}
/* static */ void
PromiseDebugging::GetPromiseID(GlobalObject&,
Promise& aPromise,
nsString& aID)
{
uint64_t promiseID = aPromise.GetID();
aID = sIDPrefix;
aID.AppendInt(promiseID);
}
/* static */ void
PromiseDebugging::FlushUncaughtRejectionsInternal()
{
CycleCollectedJSRuntime* storage = CycleCollectedJSRuntime::Get();
// The Promise that have been left uncaught (rejected and last in
// their chain) since the last call to this function.
nsTArray<nsCOMPtr<nsISupports>> uncaught;
storage->mUncaughtRejections.SwapElements(uncaught);
// The Promise that have been left uncaught at some point, but that
// have eventually had their `then` method called.
nsTArray<nsCOMPtr<nsISupports>> consumed;
storage->mConsumedRejections.SwapElements(consumed);
nsTArray<nsCOMPtr<nsISupports>>& observers = storage->mUncaughtRejectionObservers;
nsresult rv;
// Notify observers of uncaught Promise.
for (size_t i = 0; i < uncaught.Length(); ++i) {
nsCOMPtr<Promise> promise = do_QueryInterface(uncaught[i], &rv);
MOZ_ASSERT(NS_SUCCEEDED(rv));
if (!promise->IsLastInChain()) {
// This promise is not the last in the chain anymore,
// so the error has been caught at some point.
continue;
}
// For the moment, the Promise is still at the end of the
// chain. Let's inform observers, so that they may decide whether
// to report it.
for (size_t j = 0; j < observers.Length(); ++j) {
ErrorResult err;
nsRefPtr<UncaughtRejectionObserver> obs =
static_cast<UncaughtRejectionObserver*>(observers[j].get());
obs->OnLeftUncaught(*promise, err); // Ignore errors
}
promise->SetNotifiedAsUncaught();
}
// Notify observers of consumed Promise.
for (size_t i = 0; i < consumed.Length(); ++i) {
nsCOMPtr<Promise> promise = do_QueryInterface(consumed[i], &rv);
MOZ_ASSERT(NS_SUCCEEDED(rv));
if (!promise->WasNotifiedAsUncaught()) {
continue;
}
MOZ_ASSERT(!promise->IsLastInChain());
for (size_t j = 0; j < observers.Length(); ++j) {
ErrorResult err;
nsRefPtr<UncaughtRejectionObserver> obs =
static_cast<UncaughtRejectionObserver*>(observers[j].get());
obs->OnConsumed(*promise, err); // Ignore errors
}
}
}
} // namespace dom
} // namespace mozilla