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/* -*- 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,
#include "mozilla/dom/PromiseDebugging.h"
#include "js/Value.h"
#include "mozilla/CycleCollectedJSContext.h"
#include "mozilla/RefPtr.h"
#include "mozilla/SchedulerGroup.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/PromiseBinding.h"
#include "mozilla/dom/PromiseDebuggingBinding.h"
#include "nsThreadUtils.h"
namespace mozilla::dom {
class FlushRejections : public DiscardableRunnable {
public:
FlushRejections() : DiscardableRunnable("dom::FlushRejections") {}
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);
// Dispatch the runnable to the current thread where
// the Promise was rejected, e.g. workers or worklets.
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() override {
FlushSync();
return NS_OK;
}
private:
// `true` if an instance of `FlushRejections` is currently dispatched
// and has not been executed yet.
static MOZ_THREAD_LOCAL(bool) sDispatched;
};
/* static */ MOZ_THREAD_LOCAL(bool) FlushRejections::sDispatched;
/* static */
void PromiseDebugging::GetState(GlobalObject& aGlobal,
JS::Handle<JSObject*> aPromise,
PromiseDebuggingStateHolder& aState,
ErrorResult& aRv) {
JSContext* cx = aGlobal.Context();
// CheckedUnwrapStatic is fine, since we're looking for promises only.
JS::Rooted<JSObject*> obj(cx, js::CheckedUnwrapStatic(aPromise));
if (!obj || !JS::IsPromiseObject(obj)) {
aRv.ThrowTypeError<MSG_IS_NOT_PROMISE>();
return;
}
switch (JS::GetPromiseState(obj)) {
case JS::PromiseState::Pending:
aState.mState = PromiseDebuggingState::Pending;
break;
case JS::PromiseState::Fulfilled:
aState.mState = PromiseDebuggingState::Fulfilled;
aState.mValue = JS::GetPromiseResult(obj);
break;
case JS::PromiseState::Rejected:
aState.mState = PromiseDebuggingState::Rejected;
aState.mReason = JS::GetPromiseResult(obj);
break;
}
}
/* static */
void PromiseDebugging::GetPromiseID(GlobalObject& aGlobal,
JS::Handle<JSObject*> aPromise,
nsString& aID, ErrorResult& aRv) {
JSContext* cx = aGlobal.Context();
// CheckedUnwrapStatic is fine, since we're looking for promises only.
JS::Rooted<JSObject*> obj(cx, js::CheckedUnwrapStatic(aPromise));
if (!obj || !JS::IsPromiseObject(obj)) {
aRv.ThrowTypeError<MSG_IS_NOT_PROMISE>();
return;
}
uint64_t promiseID = JS::GetPromiseID(obj);
aID = sIDPrefix;
aID.AppendInt(promiseID);
}
/* static */
void PromiseDebugging::GetAllocationStack(GlobalObject& aGlobal,
JS::Handle<JSObject*> aPromise,
JS::MutableHandle<JSObject*> aStack,
ErrorResult& aRv) {
JSContext* cx = aGlobal.Context();
// CheckedUnwrapStatic is fine, since we're looking for promises only.
JS::Rooted<JSObject*> obj(cx, js::CheckedUnwrapStatic(aPromise));
if (!obj || !JS::IsPromiseObject(obj)) {
aRv.ThrowTypeError<MSG_IS_NOT_PROMISE>();
return;
}
aStack.set(JS::GetPromiseAllocationSite(obj));
}
/* static */
void PromiseDebugging::GetRejectionStack(GlobalObject& aGlobal,
JS::Handle<JSObject*> aPromise,
JS::MutableHandle<JSObject*> aStack,
ErrorResult& aRv) {
JSContext* cx = aGlobal.Context();
// CheckedUnwrapStatic is fine, since we're looking for promises only.
JS::Rooted<JSObject*> obj(cx, js::CheckedUnwrapStatic(aPromise));
if (!obj || !JS::IsPromiseObject(obj)) {
aRv.ThrowTypeError<MSG_IS_NOT_PROMISE>();
return;
}
aStack.set(JS::GetPromiseResolutionSite(obj));
}
/* static */
void PromiseDebugging::GetFullfillmentStack(GlobalObject& aGlobal,
JS::Handle<JSObject*> aPromise,
JS::MutableHandle<JSObject*> aStack,
ErrorResult& aRv) {
JSContext* cx = aGlobal.Context();
// CheckedUnwrapStatic is fine, since we're looking for promises only.
JS::Rooted<JSObject*> obj(cx, js::CheckedUnwrapStatic(aPromise));
if (!obj || !JS::IsPromiseObject(obj)) {
aRv.ThrowTypeError<MSG_IS_NOT_PROMISE>();
return;
}
aStack.set(JS::GetPromiseResolutionSite(obj));
}
/*static */
MOZ_RUNINIT nsString PromiseDebugging::sIDPrefix;
/* static */
void PromiseDebugging::Init() {
FlushRejections::Init();
// Generate a prefix for identifiers: "PromiseDebugging.$processid."
sIDPrefix = u"PromiseDebugging."_ns;
if (XRE_IsContentProcess()) {
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::AddUncaughtRejectionObserver(
GlobalObject&, UncaughtRejectionObserver& aObserver) {
CycleCollectedJSContext* storage = CycleCollectedJSContext::Get();
nsTArray<nsCOMPtr<nsISupports>>& observers =
storage->mUncaughtRejectionObservers;
observers.AppendElement(&aObserver);
}
/* static */
bool PromiseDebugging::RemoveUncaughtRejectionObserver(
GlobalObject&, UncaughtRejectionObserver& aObserver) {
CycleCollectedJSContext* storage = CycleCollectedJSContext::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(JS::Handle<JSObject*> aPromise) {
// This might OOM, but won't set a pending exception, so we'll just ignore it.
if (CycleCollectedJSContext::Get()->mUncaughtRejections.append(aPromise)) {
FlushRejections::DispatchNeeded();
}
}
/* void */
void PromiseDebugging::AddConsumedRejection(JS::Handle<JSObject*> aPromise) {
// If the promise is in our list of uncaught rejections, we haven't yet
// reported it as unhandled. In that case, just remove it from the list
// and don't add it to the list of consumed rejections.
auto& uncaughtRejections =
CycleCollectedJSContext::Get()->mUncaughtRejections;
for (size_t i = 0; i < uncaughtRejections.length(); i++) {
if (uncaughtRejections[i] == aPromise) {
// To avoid large amounts of memmoves, we don't shrink the vector here.
// Instead, we filter out nullptrs when iterating over the vector later.
uncaughtRejections[i].set(nullptr);
return;
}
}
// This might OOM, but won't set a pending exception, so we'll just ignore it.
if (CycleCollectedJSContext::Get()->mConsumedRejections.append(aPromise)) {
FlushRejections::DispatchNeeded();
}
}
/* static */
void PromiseDebugging::FlushUncaughtRejectionsInternal() {
CycleCollectedJSContext* storage = CycleCollectedJSContext::Get();
auto& uncaught = storage->mUncaughtRejections;
auto& consumed = storage->mConsumedRejections;
AutoJSAPI jsapi;
jsapi.Init();
JSContext* cx = jsapi.cx();
// Notify observers of uncaught Promise.
auto& observers = storage->mUncaughtRejectionObservers;
for (size_t i = 0; i < uncaught.length(); i++) {
JS::Rooted<JSObject*> promise(cx, uncaught[i]);
// Filter out nullptrs which might've been added by
// PromiseDebugging::AddConsumedRejection.
if (!promise) {
continue;
}
bool suppressReporting = false;
for (size_t j = 0; j < observers.Length(); ++j) {
RefPtr<UncaughtRejectionObserver> obs =
static_cast<UncaughtRejectionObserver*>(observers[j].get());
if (obs->OnLeftUncaught(promise, IgnoreErrors())) {
suppressReporting = true;
}
}
if (!suppressReporting) {
JSAutoRealm ar(cx, promise);
Promise::ReportRejectedPromise(cx, promise);
}
}
storage->mUncaughtRejections.clear();
// Notify observers of consumed Promise.
for (size_t i = 0; i < consumed.length(); i++) {
JS::Rooted<JSObject*> promise(cx, consumed[i]);
for (size_t j = 0; j < observers.Length(); ++j) {
RefPtr<UncaughtRejectionObserver> obs =
static_cast<UncaughtRejectionObserver*>(observers[j].get());
obs->OnConsumed(promise, IgnoreErrors());
}
}
storage->mConsumedRejections.clear();
}
} // namespace mozilla::dom