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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
#include "nsThreadManager.h"
#include "nsThread.h"
#include "nsThreadPool.h"
#include "nsThreadUtils.h"
#include "nsIClassInfoImpl.h"
#include "nsExceptionHandler.h"
#include "nsTArray.h"
#include "nsXULAppAPI.h"
#include "nsExceptionHandler.h"
#include "mozilla/AbstractThread.h"
#include "mozilla/AppShutdown.h"
#include "mozilla/ClearOnShutdown.h"
#include "mozilla/CycleCollectedJSContext.h" // nsAutoMicroTask
#include "mozilla/EventQueue.h"
#include "mozilla/InputTaskManager.h"
#include "mozilla/Mutex.h"
#include "mozilla/NeverDestroyed.h"
#include "mozilla/Perfetto.h"
#include "mozilla/Preferences.h"
#include "mozilla/ProfilerMarkers.h"
#include "mozilla/SpinEventLoopUntil.h"
#include "mozilla/StaticPtr.h"
#include "mozilla/TaskQueue.h"
#include "mozilla/ThreadEventQueue.h"
#include "mozilla/ThreadLocal.h"
#include "TaskController.h"
#include "ThreadEventTarget.h"
#ifdef MOZ_CANARY
# include <fcntl.h>
# include <unistd.h>
#endif
#include "MainThreadIdlePeriod.h"
using namespace mozilla;
static MOZ_THREAD_LOCAL(bool) sTLSIsMainThread;
bool NS_IsMainThreadTLSInitialized() { return sTLSIsMainThread.initialized(); }
class BackgroundEventTarget final : public nsIEventTarget,
public TaskQueueTracker {
public:
NS_DECL_THREADSAFE_ISUPPORTS
NS_DECL_NSIEVENTTARGET_FULL
BackgroundEventTarget() = default;
nsresult Init();
already_AddRefed<TaskQueue> CreateBackgroundTaskQueue(const char* aName);
void BeginShutdown(nsTArray<RefPtr<ShutdownPromise>>&);
void FinishShutdown();
private:
~BackgroundEventTarget() = default;
nsCOMPtr<nsIThreadPool> mPool;
nsCOMPtr<nsIThreadPool> mIOPool;
};
NS_IMPL_ISUPPORTS(BackgroundEventTarget, nsIEventTarget, TaskQueueTracker)
nsresult BackgroundEventTarget::Init() {
nsCOMPtr<nsIThreadPool> pool(new nsThreadPool());
NS_ENSURE_TRUE(pool, NS_ERROR_FAILURE);
nsresult rv = pool->SetName("BackgroundThreadPool"_ns);
NS_ENSURE_SUCCESS(rv, rv);
// Use potentially more conservative stack size.
rv = pool->SetThreadStackSize(nsIThreadManager::kThreadPoolStackSize);
NS_ENSURE_SUCCESS(rv, rv);
// Thread limit of 2 makes deadlock during synchronous dispatch less likely.
rv = pool->SetThreadLimit(2);
NS_ENSURE_SUCCESS(rv, rv);
rv = pool->SetIdleThreadLimit(1);
NS_ENSURE_SUCCESS(rv, rv);
// Leave threads alive for up to 5 minutes
rv = pool->SetIdleThreadTimeout(300000);
NS_ENSURE_SUCCESS(rv, rv);
// Initialize the background I/O event target.
nsCOMPtr<nsIThreadPool> ioPool(new nsThreadPool());
NS_ENSURE_TRUE(pool, NS_ERROR_FAILURE);
// The io pool spends a lot of its time blocking on io, so we want to offload
// these jobs on a lower priority if available.
rv = ioPool->SetQoSForThreads(nsIThread::QOS_PRIORITY_LOW);
NS_ENSURE_SUCCESS(
rv, rv); // note: currently infallible, keeping this for brevity.
rv = ioPool->SetName("BgIOThreadPool"_ns);
NS_ENSURE_SUCCESS(rv, rv);
// Use potentially more conservative stack size.
rv = ioPool->SetThreadStackSize(nsIThreadManager::kThreadPoolStackSize);
NS_ENSURE_SUCCESS(rv, rv);
// Thread limit of 4 makes deadlock during synchronous dispatch less likely.
rv = ioPool->SetThreadLimit(4);
NS_ENSURE_SUCCESS(rv, rv);
rv = ioPool->SetIdleThreadLimit(1);
NS_ENSURE_SUCCESS(rv, rv);
// Leave threads alive for up to 5 minutes
rv = ioPool->SetIdleThreadTimeout(300000);
NS_ENSURE_SUCCESS(rv, rv);
pool.swap(mPool);
ioPool.swap(mIOPool);
return NS_OK;
}
NS_IMETHODIMP_(bool)
BackgroundEventTarget::IsOnCurrentThreadInfallible() {
return mPool->IsOnCurrentThread() || mIOPool->IsOnCurrentThread();
}
NS_IMETHODIMP
BackgroundEventTarget::IsOnCurrentThread(bool* aValue) {
bool value = false;
if (NS_SUCCEEDED(mPool->IsOnCurrentThread(&value)) && value) {
*aValue = value;
return NS_OK;
}
return mIOPool->IsOnCurrentThread(aValue);
}
NS_IMETHODIMP
BackgroundEventTarget::Dispatch(already_AddRefed<nsIRunnable> aRunnable,
uint32_t aFlags) {
// We need to be careful here, because if an event is getting dispatched here
// from within TaskQueue::Runner::Run, it will be dispatched with
// NS_DISPATCH_AT_END, but we might not be running the event on the same
// pool, depending on which pool we were on and the dispatch flags. If we
// dispatch an event with NS_DISPATCH_AT_END to the wrong pool, the pool
// may not process the event in a timely fashion, which can lead to deadlock.
uint32_t flags = aFlags & ~NS_DISPATCH_EVENT_MAY_BLOCK;
bool mayBlock = bool(aFlags & NS_DISPATCH_EVENT_MAY_BLOCK);
nsCOMPtr<nsIThreadPool>& pool = mayBlock ? mIOPool : mPool;
// If we're already running on the pool we want to dispatch to, we can
// unconditionally add NS_DISPATCH_AT_END to indicate that we shouldn't spin
// up a new thread.
//
// Otherwise, we should remove NS_DISPATCH_AT_END so we don't run into issues
// like those in the above comment.
if (pool->IsOnCurrentThread()) {
flags |= NS_DISPATCH_AT_END;
} else {
flags &= ~NS_DISPATCH_AT_END;
}
return pool->Dispatch(std::move(aRunnable), flags);
}
NS_IMETHODIMP
BackgroundEventTarget::DispatchFromScript(nsIRunnable* aRunnable,
uint32_t aFlags) {
nsCOMPtr<nsIRunnable> runnable(aRunnable);
return Dispatch(runnable.forget(), aFlags);
}
NS_IMETHODIMP
BackgroundEventTarget::DelayedDispatch(already_AddRefed<nsIRunnable> aRunnable,
uint32_t) {
nsCOMPtr<nsIRunnable> dropRunnable(aRunnable);
return NS_ERROR_NOT_IMPLEMENTED;
}
NS_IMETHODIMP
BackgroundEventTarget::RegisterShutdownTask(nsITargetShutdownTask* aTask) {
return NS_ERROR_NOT_IMPLEMENTED;
}
NS_IMETHODIMP
BackgroundEventTarget::UnregisterShutdownTask(nsITargetShutdownTask* aTask) {
return NS_ERROR_NOT_IMPLEMENTED;
}
void BackgroundEventTarget::BeginShutdown(
nsTArray<RefPtr<ShutdownPromise>>& promises) {
auto queues = GetAllTrackedTaskQueues();
for (auto& queue : queues) {
promises.AppendElement(queue->BeginShutdown());
}
}
void BackgroundEventTarget::FinishShutdown() {
mPool->Shutdown();
mIOPool->Shutdown();
}
already_AddRefed<TaskQueue> BackgroundEventTarget::CreateBackgroundTaskQueue(
const char* aName) {
return TaskQueue::Create(do_AddRef(this), aName).forget();
}
extern "C" {
// This uses the C language linkage because it's exposed to Rust
// via the xpcom/rust/moz_task crate.
bool NS_IsMainThread() { return sTLSIsMainThread.get(); }
}
void NS_SetMainThread() {
if (!sTLSIsMainThread.init()) {
MOZ_CRASH();
}
sTLSIsMainThread.set(true);
MOZ_ASSERT(NS_IsMainThread());
// We initialize the SerialEventTargetGuard's TLS here for simplicity as it
// needs to be initialized around the same time you would initialize
// sTLSIsMainThread.
SerialEventTargetGuard::InitTLS();
nsThreadPool::InitTLS();
}
#ifdef DEBUG
namespace mozilla {
void AssertIsOnMainThread() { MOZ_ASSERT(NS_IsMainThread(), "Wrong thread!"); }
} // namespace mozilla
#endif
//-----------------------------------------------------------------------------
/* static */
void nsThreadManager::ReleaseThread(void* aData) {
static_cast<nsThread*>(aData)->Release();
}
// statically allocated instance
NS_IMETHODIMP_(MozExternalRefCountType)
nsThreadManager::AddRef() { return 2; }
NS_IMETHODIMP_(MozExternalRefCountType)
nsThreadManager::Release() { return 1; }
NS_IMPL_CLASSINFO(nsThreadManager, nullptr,
nsIClassInfo::THREADSAFE | nsIClassInfo::SINGLETON,
NS_THREADMANAGER_CID)
NS_IMPL_QUERY_INTERFACE_CI(nsThreadManager, nsIThreadManager)
NS_IMPL_CI_INTERFACE_GETTER(nsThreadManager, nsIThreadManager)
//-----------------------------------------------------------------------------
/*static*/ nsThreadManager& nsThreadManager::get() {
static NeverDestroyed<nsThreadManager> sInstance;
return *sInstance;
}
nsThreadManager::nsThreadManager()
: mCurThreadIndex(0),
mMutex("nsThreadManager::mMutex"),
mState(State::eUninit) {}
nsThreadManager::~nsThreadManager() = default;
nsresult nsThreadManager::Init() {
// Initialize perfetto if on Android.
InitPerfetto();
// Child processes need to initialize the thread manager before they
// initialize XPCOM in order to set up the crash reporter. This leads to
// situations where we get initialized twice.
{
OffTheBooksMutexAutoLock lock(mMutex);
if (mState > State::eUninit) {
return NS_OK;
}
}
if (PR_NewThreadPrivateIndex(&mCurThreadIndex, ReleaseThread) == PR_FAILURE) {
return NS_ERROR_FAILURE;
}
#ifdef MOZ_CANARY
const int flags = O_WRONLY | O_APPEND | O_CREAT | O_NONBLOCK;
const mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
char* env_var_flag = getenv("MOZ_KILL_CANARIES");
sCanaryOutputFD =
env_var_flag
? (env_var_flag[0] ? open(env_var_flag, flags, mode) : STDERR_FILENO)
: 0;
#endif
TaskController::Initialize();
// Initialize idle handling.
nsCOMPtr<nsIIdlePeriod> idlePeriod = new MainThreadIdlePeriod();
TaskController::Get()->SetIdleTaskManager(
new IdleTaskManager(idlePeriod.forget()));
// Create main thread queue that forwards events to TaskController and
// construct main thread.
UniquePtr<EventQueue> queue = MakeUnique<EventQueue>(true);
RefPtr<ThreadEventQueue> synchronizedQueue =
new ThreadEventQueue(std::move(queue), true);
mMainThread =
new nsThread(WrapNotNull(synchronizedQueue), nsThread::MAIN_THREAD,
{0, false, false, Some(W3_LONGTASK_BUSY_WINDOW_MS)});
nsresult rv = mMainThread->InitCurrentThread();
if (NS_FAILED(rv)) {
mMainThread = nullptr;
return rv;
}
#ifdef MOZ_MEMORY
jemalloc_set_main_thread();
#endif
// Init AbstractThread.
AbstractThread::InitTLS();
AbstractThread::InitMainThread();
// Initialize the background event target.
RefPtr<BackgroundEventTarget> target(new BackgroundEventTarget());
rv = target->Init();
NS_ENSURE_SUCCESS(rv, rv);
{
OffTheBooksMutexAutoLock lock(mMutex);
mBackgroundEventTarget = std::move(target);
mState = State::eActive;
}
return NS_OK;
}
void nsThreadManager::ShutdownNonMainThreads() {
MOZ_ASSERT(NS_IsMainThread(), "shutdown not called from main thread");
// Empty the main thread event queue before we begin shutting down threads.
NS_ProcessPendingEvents(mMainThread);
mMainThread->mEvents->RunShutdownTasks();
RefPtr<BackgroundEventTarget> backgroundEventTarget;
{
OffTheBooksMutexAutoLock lock(mMutex);
MOZ_ASSERT(mState == State::eActive, "shutdown called multiple times");
backgroundEventTarget = mBackgroundEventTarget;
}
nsTArray<RefPtr<ShutdownPromise>> promises;
backgroundEventTarget->BeginShutdown(promises);
bool taskQueuesShutdown = false;
// It's fine to capture everything by reference in the Then handler since it
// runs before we exit the nested event loop, thanks to the SpinEventLoopUntil
// below.
ShutdownPromise::All(mMainThread, promises)->Then(mMainThread, __func__, [&] {
backgroundEventTarget->FinishShutdown();
taskQueuesShutdown = true;
});
// Wait for task queues to shutdown, so we don't shut down the underlying
// threads of the background event target in the block below, thereby
// preventing the task queues from emptying, preventing the shutdown promises
// from resolving, and prevent anything checking `taskQueuesShutdown` from
// working.
mozilla::SpinEventLoopUntil(
"nsThreadManager::Shutdown"_ns, [&]() { return taskQueuesShutdown; },
mMainThread);
{
// Prevent new nsThreads from being created, and collect a list of threads
// which need to be shut down.
//
// We don't prevent new thread creation until we've shut down background
// task queues, to ensure that they are able to start thread pool threads
// for shutdown tasks.
nsTArray<RefPtr<nsThread>> threadsToShutdown;
{
OffTheBooksMutexAutoLock lock(mMutex);
mState = State::eShutdown;
for (auto* thread : mThreadList) {
if (thread->ShutdownRequired()) {
threadsToShutdown.AppendElement(thread);
}
}
}
// It's tempting to walk the list of threads here and tell them each to stop
// accepting new events, but that could lead to badness if one of those
// threads is stuck waiting for a response from another thread. To do it
// right, we'd need some way to interrupt the threads.
//
// Instead, we process events on the current thread while waiting for
// threads to shutdown. This means that we have to preserve a mostly
// functioning world until such time as the threads exit.
// As we're going to be waiting for all asynchronous shutdowns below, we
// can begin asynchronously shutting down all XPCOM threads here, rather
// than shutting each thread down one-at-a-time.
for (const auto& thread : threadsToShutdown) {
thread->AsyncShutdown();
}
}
// NB: It's possible that there are events in the queue that want to *start*
// an asynchronous shutdown. But we have already started async shutdown of
// the threads above, so there's no need to worry about them. We only have to
// wait for all in-flight asynchronous thread shutdowns to complete.
mMainThread->WaitForAllAsynchronousShutdowns();
// There are no more background threads at this point.
}
void nsThreadManager::ShutdownMainThread() {
#ifdef DEBUG
{
OffTheBooksMutexAutoLock lock(mMutex);
MOZ_ASSERT(mState == State::eShutdown, "Must have called BeginShutdown");
}
#endif
// Do NS_ProcessPendingEvents but with special handling to set
// mEventsAreDoomed atomically with the removal of the last event. This means
// that PutEvent cannot succeed if the event would be left in the main thread
// queue after our final call to NS_ProcessPendingEvents.
// See comments in `nsThread::ThreadFunc` for a more detailed explanation.
while (true) {
if (mMainThread->mEvents->ShutdownIfNoPendingEvents()) {
break;
}
NS_ProcessPendingEvents(mMainThread);
}
// Normally thread shutdown clears the observer for the thread, but since the
// main thread is special we do it manually here after we're sure all events
// have been processed.
mMainThread->SetObserver(nullptr);
OffTheBooksMutexAutoLock lock(mMutex);
mBackgroundEventTarget = nullptr;
}
void nsThreadManager::ReleaseMainThread() {
#ifdef DEBUG
{
OffTheBooksMutexAutoLock lock(mMutex);
MOZ_ASSERT(mState == State::eShutdown, "Must have called BeginShutdown");
MOZ_ASSERT(!mBackgroundEventTarget, "Must have called ShutdownMainThread");
}
#endif
MOZ_ASSERT(mMainThread);
// Release main thread object.
mMainThread = nullptr;
// Remove the TLS entry for the main thread.
PR_SetThreadPrivate(mCurThreadIndex, nullptr);
}
void nsThreadManager::RegisterCurrentThread(nsThread& aThread) {
MOZ_ASSERT(aThread.GetPRThread() == PR_GetCurrentThread(), "bad aThread");
aThread.AddRef(); // for TLS entry
PR_SetThreadPrivate(mCurThreadIndex, &aThread);
#ifdef DEBUG
{
OffTheBooksMutexAutoLock lock(mMutex);
MOZ_ASSERT(aThread.isInList(),
"Thread was not added to the thread list before registering!");
}
#endif
}
void nsThreadManager::UnregisterCurrentThread(nsThread& aThread) {
MOZ_ASSERT(aThread.GetPRThread() == PR_GetCurrentThread(), "bad aThread");
PR_SetThreadPrivate(mCurThreadIndex, nullptr);
// Ref-count balanced via ReleaseThread
}
// Not to be used for MainThread!
nsThread* nsThreadManager::CreateCurrentThread(SynchronizedEventQueue* aQueue) {
// Make sure we don't have an nsThread yet.
MOZ_ASSERT(!PR_GetThreadPrivate(mCurThreadIndex));
if (!AllowNewXPCOMThreads()) {
return nullptr;
}
RefPtr<nsThread> thread = new nsThread(
WrapNotNull(aQueue), nsThread::NOT_MAIN_THREAD, {.stackSize = 0});
if (NS_FAILED(thread->InitCurrentThread())) {
return nullptr;
}
return thread.get(); // reference held in TLS
}
nsresult nsThreadManager::DispatchToBackgroundThread(nsIRunnable* aEvent,
uint32_t aDispatchFlags) {
RefPtr<BackgroundEventTarget> backgroundTarget;
{
OffTheBooksMutexAutoLock lock(mMutex);
if (!AllowNewXPCOMThreadsLocked() || !mBackgroundEventTarget) {
return NS_ERROR_FAILURE;
}
backgroundTarget = mBackgroundEventTarget;
}
return backgroundTarget->Dispatch(aEvent, aDispatchFlags);
}
already_AddRefed<TaskQueue> nsThreadManager::CreateBackgroundTaskQueue(
const char* aName) {
RefPtr<BackgroundEventTarget> backgroundTarget;
{
OffTheBooksMutexAutoLock lock(mMutex);
if (!AllowNewXPCOMThreadsLocked() || !mBackgroundEventTarget) {
return nullptr;
}
backgroundTarget = mBackgroundEventTarget;
}
return backgroundTarget->CreateBackgroundTaskQueue(aName);
}
nsThread* nsThreadManager::GetCurrentThread() {
// read thread local storage
void* data = PR_GetThreadPrivate(mCurThreadIndex);
if (data) {
return static_cast<nsThread*>(data);
}
// Keep this function working early during startup or late during shutdown on
// the main thread.
if (!AllowNewXPCOMThreads() || NS_IsMainThread()) {
return nullptr;
}
// OK, that's fine. We'll dynamically create one :-)
//
// We assume that if we're implicitly creating a thread here that it doesn't
// want an event queue. Any thread which wants an event queue should
// explicitly create its nsThread wrapper.
//
// nsThread::InitCurrentThread() will check AllowNewXPCOMThreads, and return
// an error if we're too late in shutdown to create new XPCOM threads.
RefPtr<nsThread> thread = new nsThread();
if (NS_FAILED(thread->InitCurrentThread())) {
return nullptr;
}
return thread.get(); // reference held in TLS
}
bool nsThreadManager::IsNSThread() const {
{
OffTheBooksMutexAutoLock lock(mMutex);
if (mState == State::eUninit) {
return false;
}
}
if (auto* thread = (nsThread*)PR_GetThreadPrivate(mCurThreadIndex)) {
return thread->EventQueue();
}
return false;
}
NS_IMETHODIMP
nsThreadManager::NewNamedThread(
const nsACString& aName, nsIThreadManager::ThreadCreationOptions aOptions,
nsIThread** aResult) {
// Note: can be called from arbitrary threads
[[maybe_unused]] TimeStamp startTime = TimeStamp::Now();
RefPtr<ThreadEventQueue> queue =
new ThreadEventQueue(MakeUnique<EventQueue>());
RefPtr<nsThread> thr =
new nsThread(WrapNotNull(queue), nsThread::NOT_MAIN_THREAD, aOptions);
// Note: nsThread::Init() will check AllowNewXPCOMThreads, and return an
// error if we're too late in shutdown to create new XPCOM threads. If we
// aren't, the thread will be synchronously added to mThreadList.
nsresult rv = thr->Init(aName);
if (NS_FAILED(rv)) {
return rv;
}
PROFILER_MARKER_TEXT(
"NewThread", OTHER,
MarkerOptions(MarkerStack::Capture(),
MarkerTiming::IntervalUntilNowFrom(startTime)),
aName);
if (!NS_IsMainThread()) {
PROFILER_MARKER_TEXT(
"NewThread (non-main thread)", OTHER,
MarkerOptions(MarkerStack::Capture(), MarkerThreadId::MainThread(),
MarkerTiming::IntervalUntilNowFrom(startTime)),
aName);
}
thr.forget(aResult);
return NS_OK;
}
NS_IMETHODIMP
nsThreadManager::GetMainThread(nsIThread** aResult) {
// Keep this functioning during Shutdown
if (!mMainThread) {
if (!NS_IsMainThread()) {
NS_WARNING(
"Called GetMainThread but there isn't a main thread and "
"we're not the main thread.");
}
return NS_ERROR_NOT_INITIALIZED;
}
NS_ADDREF(*aResult = mMainThread);
return NS_OK;
}
NS_IMETHODIMP
nsThreadManager::GetCurrentThread(nsIThread** aResult) {
// Keep this functioning during Shutdown
if (!mMainThread) {
return NS_ERROR_NOT_INITIALIZED;
}
*aResult = GetCurrentThread();
if (!*aResult) {
return NS_ERROR_OUT_OF_MEMORY;
}
NS_ADDREF(*aResult);
return NS_OK;
}
NS_IMETHODIMP
nsThreadManager::SpinEventLoopUntil(const nsACString& aVeryGoodReasonToDoThis,
nsINestedEventLoopCondition* aCondition) {
return SpinEventLoopUntilInternal(aVeryGoodReasonToDoThis, aCondition,
ShutdownPhase::NotInShutdown);
}
NS_IMETHODIMP
nsThreadManager::SpinEventLoopUntilOrQuit(
const nsACString& aVeryGoodReasonToDoThis,
nsINestedEventLoopCondition* aCondition) {
return SpinEventLoopUntilInternal(aVeryGoodReasonToDoThis, aCondition,
ShutdownPhase::AppShutdownConfirmed);
}
// statics from SpinEventLoopUntil.h
AutoNestedEventLoopAnnotation* AutoNestedEventLoopAnnotation::sCurrent =
nullptr;
StaticMutex AutoNestedEventLoopAnnotation::sStackMutex;
// static from SpinEventLoopUntil.h
void AutoNestedEventLoopAnnotation::AnnotateXPCOMSpinEventLoopStack(
const nsACString& aStack) {
if (aStack.Length() > 0) {
nsCString prefixedStack(XRE_GetProcessTypeString());
prefixedStack += ": "_ns + aStack;
CrashReporter::RecordAnnotationNSCString(
CrashReporter::Annotation::XPCOMSpinEventLoopStack, prefixedStack);
} else {
CrashReporter::UnrecordAnnotation(
CrashReporter::Annotation::XPCOMSpinEventLoopStack);
}
}
nsresult nsThreadManager::SpinEventLoopUntilInternal(
const nsACString& aVeryGoodReasonToDoThis,
nsINestedEventLoopCondition* aCondition,
ShutdownPhase aShutdownPhaseToCheck) {
// XXX: We would want to AssertIsOnMainThread(); but that breaks some GTest.
nsCOMPtr<nsINestedEventLoopCondition> condition(aCondition);
nsresult rv = NS_OK;
if (!mozilla::SpinEventLoopUntil(aVeryGoodReasonToDoThis, [&]() -> bool {
// Check if an ongoing shutdown reached our limits.
if (aShutdownPhaseToCheck > ShutdownPhase::NotInShutdown &&
AppShutdown::GetCurrentShutdownPhase() >= aShutdownPhaseToCheck) {
return true;
}
bool isDone = false;
rv = condition->IsDone(&isDone);
// JS failure should be unusual, but we need to stop and propagate
// the error back to the caller.
if (NS_FAILED(rv)) {
return true;
}
return isDone;
})) {
// We stopped early for some reason, which is unexpected.
return NS_ERROR_UNEXPECTED;
}
// If we exited when the condition told us to, we need to return whether
// the condition encountered failure when executing.
return rv;
}
NS_IMETHODIMP
nsThreadManager::SpinEventLoopUntilEmpty() {
nsIThread* thread = NS_GetCurrentThread();
while (NS_HasPendingEvents(thread)) {
(void)NS_ProcessNextEvent(thread, false);
}
return NS_OK;
}
NS_IMETHODIMP
nsThreadManager::GetMainThreadEventTarget(nsIEventTarget** aTarget) {
nsCOMPtr<nsIEventTarget> target = GetMainThreadSerialEventTarget();
target.forget(aTarget);
return NS_OK;
}
NS_IMETHODIMP
nsThreadManager::DispatchToMainThread(nsIRunnable* aEvent, uint32_t aPriority,
uint8_t aArgc) {
// Note: C++ callers should instead use NS_DispatchToMainThread.
MOZ_ASSERT(NS_IsMainThread());
// Keep this functioning during Shutdown
if (NS_WARN_IF(!mMainThread)) {
return NS_ERROR_NOT_INITIALIZED;
}
// If aPriority wasn't explicitly passed, that means it should be treated as
// PRIORITY_NORMAL.
if (aArgc > 0 && aPriority != nsIRunnablePriority::PRIORITY_NORMAL) {
nsCOMPtr<nsIRunnable> event(aEvent);
return mMainThread->DispatchFromScript(
new PrioritizableRunnable(event.forget(), aPriority), 0);
}
return mMainThread->DispatchFromScript(aEvent, 0);
}
class AutoMicroTaskWrapperRunnable final : public Runnable {
public:
explicit AutoMicroTaskWrapperRunnable(nsIRunnable* aEvent)
: Runnable("AutoMicroTaskWrapperRunnable"), mEvent(aEvent) {
MOZ_ASSERT(aEvent);
}
private:
~AutoMicroTaskWrapperRunnable() = default;
NS_IMETHOD Run() override {
nsAutoMicroTask mt;
return mEvent->Run();
}
RefPtr<nsIRunnable> mEvent;
};
NS_IMETHODIMP
nsThreadManager::DispatchToMainThreadWithMicroTask(nsIRunnable* aEvent,
uint32_t aPriority,
uint8_t aArgc) {
RefPtr<AutoMicroTaskWrapperRunnable> runnable =
new AutoMicroTaskWrapperRunnable(aEvent);
return DispatchToMainThread(runnable, aPriority, aArgc);
}
void nsThreadManager::EnableMainThreadEventPrioritization() {
MOZ_ASSERT(NS_IsMainThread());
InputTaskManager::Get()->EnableInputEventPrioritization();
}
void nsThreadManager::FlushInputEventPrioritization() {
MOZ_ASSERT(NS_IsMainThread());
InputTaskManager::Get()->FlushInputEventPrioritization();
}
void nsThreadManager::SuspendInputEventPrioritization() {
MOZ_ASSERT(NS_IsMainThread());
InputTaskManager::Get()->SuspendInputEventPrioritization();
}
void nsThreadManager::ResumeInputEventPrioritization() {
MOZ_ASSERT(NS_IsMainThread());
InputTaskManager::Get()->ResumeInputEventPrioritization();
}
// static
bool nsThreadManager::MainThreadHasPendingHighPriorityEvents() {
MOZ_ASSERT(NS_IsMainThread());
bool retVal = false;
if (get().mMainThread) {
get().mMainThread->HasPendingHighPriorityEvents(&retVal);
}
return retVal;
}
NS_IMETHODIMP
nsThreadManager::IdleDispatchToMainThread(nsIRunnable* aEvent,
uint32_t aTimeout) {
// Note: C++ callers should instead use NS_DispatchToThreadQueue or
// NS_DispatchToCurrentThreadQueue.
MOZ_ASSERT(NS_IsMainThread());
nsCOMPtr<nsIRunnable> event(aEvent);
if (aTimeout) {
return NS_DispatchToThreadQueue(event.forget(), aTimeout, mMainThread,
EventQueuePriority::Idle);
}
return NS_DispatchToThreadQueue(event.forget(), mMainThread,
EventQueuePriority::Idle);
}
NS_IMETHODIMP
nsThreadManager::DispatchDirectTaskToCurrentThread(nsIRunnable* aEvent) {
NS_ENSURE_STATE(aEvent);
nsCOMPtr<nsIRunnable> runnable = aEvent;
return GetCurrentThread()->DispatchDirectTask(runnable.forget());
}
bool nsThreadManager::AllowNewXPCOMThreads() {
mozilla::OffTheBooksMutexAutoLock lock(mMutex);
return AllowNewXPCOMThreadsLocked();
}