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gecko-dev/xpcom/threads/nsThread.cpp

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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, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "nsThread.h"
#if !defined(MOZILLA_XPCOMRT_API)
#include "base/message_loop.h"
#endif // !defined(MOZILLA_XPCOMRT_API)
// Chromium's logging can sometimes leak through...
#ifdef LOG
#undef LOG
#endif
#include "mozilla/ReentrantMonitor.h"
#include "nsMemoryPressure.h"
#include "nsThreadManager.h"
#include "nsIClassInfoImpl.h"
#include "nsAutoPtr.h"
#include "nsCOMPtr.h"
#include "pratom.h"
#include "mozilla/Logging.h"
#include "nsIObserverService.h"
#if !defined(MOZILLA_XPCOMRT_API)
#include "mozilla/HangMonitor.h"
#include "mozilla/IOInterposer.h"
#include "mozilla/ipc/MessageChannel.h"
#include "mozilla/ipc/BackgroundChild.h"
#endif // defined(MOZILLA_XPCOMRT_API)
#include "mozilla/Services.h"
#include "nsXPCOMPrivate.h"
#include "mozilla/ChaosMode.h"
#include "mozilla/TimeStamp.h"
#ifdef MOZ_CRASHREPORTER
#include "nsServiceManagerUtils.h"
#include "nsICrashReporter.h"
#endif
#ifdef XP_LINUX
#include <sys/time.h>
#include <sys/resource.h>
#include <sched.h>
#endif
#define HAVE_UALARM _BSD_SOURCE || (_XOPEN_SOURCE >= 500 || \
_XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED) && \
!(_POSIX_C_SOURCE >= 200809L || _XOPEN_SOURCE >= 700)
#if defined(XP_LINUX) && !defined(ANDROID) && defined(_GNU_SOURCE)
#define HAVE_SCHED_SETAFFINITY
#endif
#ifdef MOZ_CANARY
# include <unistd.h>
# include <execinfo.h>
# include <signal.h>
# include <fcntl.h>
# include "nsXULAppAPI.h"
#endif
#if defined(NS_FUNCTION_TIMER) && defined(_MSC_VER)
#include "nsTimerImpl.h"
#include "mozilla/StackWalk.h"
#endif
#ifdef NS_FUNCTION_TIMER
#include "nsCRT.h"
#endif
#ifdef MOZ_TASK_TRACER
#include "GeckoTaskTracer.h"
#include "TracedTaskCommon.h"
using namespace mozilla::tasktracer;
#endif
using namespace mozilla;
static PRLogModuleInfo*
GetThreadLog()
{
static PRLogModuleInfo* sLog;
if (!sLog) {
sLog = PR_NewLogModule("nsThread");
}
return sLog;
}
#ifdef LOG
#undef LOG
#endif
#define LOG(args) MOZ_LOG(GetThreadLog(), mozilla::LogLevel::Debug, args)
NS_DECL_CI_INTERFACE_GETTER(nsThread)
nsIThreadObserver* nsThread::sMainThreadObserver = nullptr;
//-----------------------------------------------------------------------------
// Because we do not have our own nsIFactory, we have to implement nsIClassInfo
// somewhat manually.
class nsThreadClassInfo : public nsIClassInfo
{
public:
NS_DECL_ISUPPORTS_INHERITED // no mRefCnt
NS_DECL_NSICLASSINFO
nsThreadClassInfo()
{
}
};
NS_IMETHODIMP_(MozExternalRefCountType)
nsThreadClassInfo::AddRef()
{
return 2;
}
NS_IMETHODIMP_(MozExternalRefCountType)
nsThreadClassInfo::Release()
{
return 1;
}
NS_IMPL_QUERY_INTERFACE(nsThreadClassInfo, nsIClassInfo)
NS_IMETHODIMP
nsThreadClassInfo::GetInterfaces(uint32_t* aCount, nsIID*** aArray)
{
return NS_CI_INTERFACE_GETTER_NAME(nsThread)(aCount, aArray);
}
NS_IMETHODIMP
nsThreadClassInfo::GetScriptableHelper(nsIXPCScriptable** aResult)
{
*aResult = nullptr;
return NS_OK;
}
NS_IMETHODIMP
nsThreadClassInfo::GetContractID(char** aResult)
{
*aResult = nullptr;
return NS_OK;
}
NS_IMETHODIMP
nsThreadClassInfo::GetClassDescription(char** aResult)
{
*aResult = nullptr;
return NS_OK;
}
NS_IMETHODIMP
nsThreadClassInfo::GetClassID(nsCID** aResult)
{
*aResult = nullptr;
return NS_OK;
}
NS_IMETHODIMP
nsThreadClassInfo::GetFlags(uint32_t* aResult)
{
*aResult = THREADSAFE;
return NS_OK;
}
NS_IMETHODIMP
nsThreadClassInfo::GetClassIDNoAlloc(nsCID* aResult)
{
return NS_ERROR_NOT_AVAILABLE;
}
//-----------------------------------------------------------------------------
NS_IMPL_ADDREF(nsThread)
NS_IMPL_RELEASE(nsThread)
NS_INTERFACE_MAP_BEGIN(nsThread)
NS_INTERFACE_MAP_ENTRY(nsIThread)
NS_INTERFACE_MAP_ENTRY(nsIThreadInternal)
NS_INTERFACE_MAP_ENTRY(nsIEventTarget)
NS_INTERFACE_MAP_ENTRY(nsISupportsPriority)
NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIThread)
if (aIID.Equals(NS_GET_IID(nsIClassInfo))) {
static nsThreadClassInfo sThreadClassInfo;
foundInterface = static_cast<nsIClassInfo*>(&sThreadClassInfo);
} else
NS_INTERFACE_MAP_END
NS_IMPL_CI_INTERFACE_GETTER(nsThread, nsIThread, nsIThreadInternal,
nsIEventTarget, nsISupportsPriority)
//-----------------------------------------------------------------------------
class nsThreadStartupEvent : public nsRunnable
{
public:
nsThreadStartupEvent()
: mMon("nsThreadStartupEvent.mMon")
, mInitialized(false)
{
}
// This method does not return until the thread startup object is in the
// completion state.
void Wait()
{
if (mInitialized) {
// Maybe avoid locking...
return;
}
ReentrantMonitorAutoEnter mon(mMon);
while (!mInitialized) {
mon.Wait();
}
}
// This method needs to be public to support older compilers (xlC_r on AIX).
// It should be called directly as this class type is reference counted.
virtual ~nsThreadStartupEvent() {}
private:
NS_IMETHOD Run()
{
ReentrantMonitorAutoEnter mon(mMon);
mInitialized = true;
mon.Notify();
return NS_OK;
}
ReentrantMonitor mMon;
bool mInitialized;
};
//-----------------------------------------------------------------------------
struct nsThreadShutdownContext
{
nsThread* joiningThread;
bool shutdownAck;
};
// This event is responsible for notifying nsThread::Shutdown that it is time
// to call PR_JoinThread.
class nsThreadShutdownAckEvent : public nsRunnable
{
public:
explicit nsThreadShutdownAckEvent(nsThreadShutdownContext* aCtx)
: mShutdownContext(aCtx)
{
}
NS_IMETHOD Run()
{
mShutdownContext->shutdownAck = true;
return NS_OK;
}
private:
nsThreadShutdownContext* mShutdownContext;
};
// This event is responsible for setting mShutdownContext
class nsThreadShutdownEvent : public nsRunnable
{
public:
nsThreadShutdownEvent(nsThread* aThr, nsThreadShutdownContext* aCtx)
: mThread(aThr)
, mShutdownContext(aCtx)
{
}
NS_IMETHOD Run()
{
mThread->mShutdownContext = mShutdownContext;
#if !defined(MOZILLA_XPCOMRT_API)
MessageLoop::current()->Quit();
#endif // !defined(MOZILLA_XPCOMRT_API)
return NS_OK;
}
private:
nsRefPtr<nsThread> mThread;
nsThreadShutdownContext* mShutdownContext;
};
//-----------------------------------------------------------------------------
static void
SetupCurrentThreadForChaosMode()
{
if (!ChaosMode::isActive(ChaosMode::ThreadScheduling)) {
return;
}
#ifdef XP_LINUX
// PR_SetThreadPriority doesn't really work since priorities >
// PR_PRIORITY_NORMAL can't be set by non-root users. Instead we'll just use
// setpriority(2) to set random 'nice values'. In regular Linux this is only
// a dynamic adjustment so it still doesn't really do what we want, but tools
// like 'rr' can be more aggressive about honoring these values.
// Some of these calls may fail due to trying to lower the priority
// (e.g. something may have already called setpriority() for this thread).
// This makes it hard to have non-main threads with higher priority than the
// main thread, but that's hard to fix. Tools like rr can choose to honor the
// requested values anyway.
// Use just 4 priorities so there's a reasonable chance of any two threads
// having equal priority.
setpriority(PRIO_PROCESS, 0, ChaosMode::randomUint32LessThan(4));
#else
// We should set the affinity here but NSPR doesn't provide a way to expose it.
uint32_t priority = ChaosMode::randomUint32LessThan(PR_PRIORITY_LAST + 1);
PR_SetThreadPriority(PR_GetCurrentThread(), PRThreadPriority(priority));
#endif
#ifdef HAVE_SCHED_SETAFFINITY
// Force half the threads to CPU 0 so they compete for CPU
if (ChaosMode::randomUint32LessThan(2)) {
cpu_set_t cpus;
CPU_ZERO(&cpus);
CPU_SET(0, &cpus);
sched_setaffinity(0, sizeof(cpus), &cpus);
}
#endif
}
/*static*/ void
nsThread::ThreadFunc(void* aArg)
{
#if !defined(MOZILLA_XPCOMRT_API)
using mozilla::ipc::BackgroundChild;
#endif // !defined(MOZILLA_XPCOMRT_API)
nsThread* self = static_cast<nsThread*>(aArg); // strong reference
self->mThread = PR_GetCurrentThread();
SetupCurrentThreadForChaosMode();
// Inform the ThreadManager
nsThreadManager::get()->RegisterCurrentThread(self);
#if !defined(MOZILLA_XPCOMRT_API)
mozilla::IOInterposer::RegisterCurrentThread();
#endif // !defined(MOZILLA_XPCOMRT_API)
// Wait for and process startup event
nsCOMPtr<nsIRunnable> event;
if (!self->GetEvent(true, getter_AddRefs(event))) {
NS_WARNING("failed waiting for thread startup event");
return;
}
event->Run(); // unblocks nsThread::Init
event = nullptr;
{
#if defined(MOZILLA_XPCOMRT_API)
while(!self->mShutdownContext) {
NS_ProcessNextEvent();
}
#else
// Scope for MessageLoop.
nsAutoPtr<MessageLoop> loop(
new MessageLoop(MessageLoop::TYPE_MOZILLA_NONMAINTHREAD));
// Now, process incoming events...
loop->Run();
BackgroundChild::CloseForCurrentThread();
#endif // defined(MOZILLA_XPCOMRT_API)
// Do NS_ProcessPendingEvents but with special handling to set
// mEventsAreDoomed atomically with the removal of the last event. The key
// invariant here is that we will never permit PutEvent to succeed if the
// event would be left in the queue after our final call to
// NS_ProcessPendingEvents.
while (true) {
{
MutexAutoLock lock(self->mLock);
if (!self->mEvents->HasPendingEvent()) {
// No events in the queue, so we will stop now. Don't let any more
// events be added, since they won't be processed. It is critical
// that no PutEvent can occur between testing that the event queue is
// empty and setting mEventsAreDoomed!
self->mEventsAreDoomed = true;
break;
}
}
NS_ProcessPendingEvents(self);
}
}
#if !defined(MOZILLA_XPCOMRT_API)
mozilla::IOInterposer::UnregisterCurrentThread();
#endif // !defined(MOZILLA_XPCOMRT_API)
// Inform the threadmanager that this thread is going away
nsThreadManager::get()->UnregisterCurrentThread(self);
// Dispatch shutdown ACK
event = new nsThreadShutdownAckEvent(self->mShutdownContext);
self->mShutdownContext->joiningThread->Dispatch(event, NS_DISPATCH_NORMAL);
// Release any observer of the thread here.
self->SetObserver(nullptr);
#ifdef MOZ_TASK_TRACER
FreeTraceInfo();
#endif
NS_RELEASE(self);
}
//-----------------------------------------------------------------------------
#ifdef MOZ_CRASHREPORTER
// Tell the crash reporter to save a memory report if our heuristics determine
// that an OOM failure is likely to occur soon.
static bool SaveMemoryReportNearOOM()
{
bool needMemoryReport = false;
#ifdef XP_WIN // XXX implement on other platforms as needed
const size_t LOWMEM_THRESHOLD_VIRTUAL = 200 * 1024 * 1024;
MEMORYSTATUSEX statex;
statex.dwLength = sizeof(statex);
if (GlobalMemoryStatusEx(&statex)) {
if (statex.ullAvailVirtual < LOWMEM_THRESHOLD_VIRTUAL) {
needMemoryReport = true;
}
}
#endif
if (needMemoryReport) {
nsCOMPtr<nsICrashReporter> cr =
do_GetService("@mozilla.org/toolkit/crash-reporter;1");
cr->SaveMemoryReport();
}
return needMemoryReport;
}
#endif
#ifdef MOZ_CANARY
int sCanaryOutputFD = -1;
#endif
nsThread::nsThread(MainThreadFlag aMainThread, uint32_t aStackSize)
: mLock("nsThread.mLock")
, mEvents(&mEventsRoot)
, mPriority(PRIORITY_NORMAL)
, mThread(nullptr)
, mNestedEventLoopDepth(0)
, mStackSize(aStackSize)
, mShutdownContext(nullptr)
, mShutdownRequired(false)
, mEventsAreDoomed(false)
, mIsMainThread(aMainThread)
{
}
nsThread::~nsThread()
{
}
nsresult
nsThread::Init()
{
// spawn thread and wait until it is fully setup
nsRefPtr<nsThreadStartupEvent> startup = new nsThreadStartupEvent();
NS_ADDREF_THIS();
mShutdownRequired = true;
// ThreadFunc is responsible for setting mThread
PRThread* thr = PR_CreateThread(PR_USER_THREAD, ThreadFunc, this,
PR_PRIORITY_NORMAL, PR_GLOBAL_THREAD,
PR_JOINABLE_THREAD, mStackSize);
if (!thr) {
NS_RELEASE_THIS();
return NS_ERROR_OUT_OF_MEMORY;
}
// ThreadFunc will wait for this event to be run before it tries to access
// mThread. By delaying insertion of this event into the queue, we ensure
// that mThread is set properly.
{
MutexAutoLock lock(mLock);
mEventsRoot.PutEvent(startup);
}
// Wait for thread to call ThreadManager::SetupCurrentThread, which completes
// initialization of ThreadFunc.
startup->Wait();
return NS_OK;
}
nsresult
nsThread::InitCurrentThread()
{
mThread = PR_GetCurrentThread();
SetupCurrentThreadForChaosMode();
nsThreadManager::get()->RegisterCurrentThread(this);
return NS_OK;
}
nsresult
nsThread::PutEvent(nsIRunnable* aEvent, nsNestedEventTarget* aTarget)
{
nsCOMPtr<nsIThreadObserver> obs;
{
MutexAutoLock lock(mLock);
nsChainedEventQueue* queue = aTarget ? aTarget->mQueue : &mEventsRoot;
if (!queue || (queue == &mEventsRoot && mEventsAreDoomed)) {
NS_WARNING("An event was posted to a thread that will never run it (rejected)");
return NS_ERROR_UNEXPECTED;
}
queue->PutEvent(aEvent);
// Make sure to grab the observer before dropping the lock, otherwise the
// event that we just placed into the queue could run and eventually delete
// this nsThread before the calling thread is scheduled again. We would then
// crash while trying to access a dead nsThread.
obs = mObserver;
}
if (obs) {
obs->OnDispatchedEvent(this);
}
return NS_OK;
}
nsresult
nsThread::DispatchInternal(nsIRunnable* aEvent, uint32_t aFlags,
nsNestedEventTarget* aTarget)
{
if (NS_WARN_IF(!aEvent)) {
return NS_ERROR_INVALID_ARG;
}
if (gXPCOMThreadsShutDown && MAIN_THREAD != mIsMainThread && !aTarget) {
return NS_ERROR_ILLEGAL_DURING_SHUTDOWN;
}
#ifdef MOZ_TASK_TRACER
nsCOMPtr<nsIRunnable> tracedRunnable = CreateTracedRunnable(aEvent);
(static_cast<TracedRunnable*>(tracedRunnable.get()))->DispatchTask();
aEvent = tracedRunnable;
#endif
if (aFlags & DISPATCH_SYNC) {
nsThread* thread = nsThreadManager::get()->GetCurrentThread();
if (NS_WARN_IF(!thread)) {
return NS_ERROR_NOT_AVAILABLE;
}
// XXX we should be able to do something better here... we should
// be able to monitor the slot occupied by this event and use
// that to tell us when the event has been processed.
nsRefPtr<nsThreadSyncDispatch> wrapper =
new nsThreadSyncDispatch(thread, aEvent);
nsresult rv = PutEvent(wrapper, aTarget);
// Don't wait for the event to finish if we didn't dispatch it...
if (NS_FAILED(rv)) {
return rv;
}
// Allows waiting; ensure no locks are held that would deadlock us!
while (wrapper->IsPending()) {
NS_ProcessNextEvent(thread, true);
}
return wrapper->Result();
}
NS_ASSERTION(aFlags == NS_DISPATCH_NORMAL, "unexpected dispatch flags");
return PutEvent(aEvent, aTarget);
}
//-----------------------------------------------------------------------------
// nsIEventTarget
NS_IMETHODIMP
nsThread::Dispatch(nsIRunnable* aEvent, uint32_t aFlags)
{
LOG(("THRD(%p) Dispatch [%p %x]\n", this, aEvent, aFlags));
return DispatchInternal(aEvent, aFlags, nullptr);
}
NS_IMETHODIMP
nsThread::IsOnCurrentThread(bool* aResult)
{
*aResult = (PR_GetCurrentThread() == mThread);
return NS_OK;
}
//-----------------------------------------------------------------------------
// nsIThread
NS_IMETHODIMP
nsThread::GetPRThread(PRThread** aResult)
{
*aResult = mThread;
return NS_OK;
}
NS_IMETHODIMP
nsThread::Shutdown()
{
LOG(("THRD(%p) shutdown\n", this));
// XXX If we make this warn, then we hit that warning at xpcom shutdown while
// shutting down a thread in a thread pool. That happens b/c the thread
// in the thread pool is already shutdown by the thread manager.
if (!mThread) {
return NS_OK;
}
if (NS_WARN_IF(mThread == PR_GetCurrentThread())) {
return NS_ERROR_UNEXPECTED;
}
// Prevent multiple calls to this method
{
MutexAutoLock lock(mLock);
if (!mShutdownRequired) {
return NS_ERROR_UNEXPECTED;
}
mShutdownRequired = false;
}
nsThreadShutdownContext context;
context.joiningThread = nsThreadManager::get()->GetCurrentThread();
context.shutdownAck = false;
// Set mShutdownContext and wake up the thread in case it is waiting for
// events to process.
nsCOMPtr<nsIRunnable> event = new nsThreadShutdownEvent(this, &context);
// XXXroc What if posting the event fails due to OOM?
PutEvent(event, nullptr);
// We could still end up with other events being added after the shutdown
// task, but that's okay because we process pending events in ThreadFunc
// after setting mShutdownContext just before exiting.
// Process events on the current thread until we receive a shutdown ACK.
// Allows waiting; ensure no locks are held that would deadlock us!
while (!context.shutdownAck) {
NS_ProcessNextEvent(context.joiningThread, true);
}
// Now, it should be safe to join without fear of dead-locking.
PR_JoinThread(mThread);
mThread = nullptr;
// We hold strong references to our event observers, and once the thread is
// shut down the observers can't easily unregister themselves. Do it here
// to avoid leaking.
ClearObservers();
#ifdef DEBUG
{
MutexAutoLock lock(mLock);
MOZ_ASSERT(!mObserver, "Should have been cleared at shutdown!");
}
#endif
return NS_OK;
}
NS_IMETHODIMP
nsThread::HasPendingEvents(bool* aResult)
{
if (NS_WARN_IF(PR_GetCurrentThread() != mThread)) {
return NS_ERROR_NOT_SAME_THREAD;
}
*aResult = mEvents->GetEvent(false, nullptr);
return NS_OK;
}
#ifdef MOZ_CANARY
void canary_alarm_handler(int signum);
class Canary
{
//XXX ToDo: support nested loops
public:
Canary()
{
if (sCanaryOutputFD > 0 && EventLatencyIsImportant()) {
signal(SIGALRM, canary_alarm_handler);
ualarm(15000, 0);
}
}
~Canary()
{
if (sCanaryOutputFD != 0 && EventLatencyIsImportant()) {
ualarm(0, 0);
}
}
static bool EventLatencyIsImportant()
{
return NS_IsMainThread() && XRE_IsParentProcess();
}
};
void canary_alarm_handler(int signum)
{
void* array[30];
const char msg[29] = "event took too long to run:\n";
// use write to be safe in the signal handler
write(sCanaryOutputFD, msg, sizeof(msg));
backtrace_symbols_fd(array, backtrace(array, 30), sCanaryOutputFD);
}
#endif
#define NOTIFY_EVENT_OBSERVERS(func_, params_) \
PR_BEGIN_MACRO \
if (!mEventObservers.IsEmpty()) { \
nsAutoTObserverArray<nsCOMPtr<nsIThreadObserver>, 2>::ForwardIterator \
iter_(mEventObservers); \
nsCOMPtr<nsIThreadObserver> obs_; \
while (iter_.HasMore()) { \
obs_ = iter_.GetNext(); \
obs_ -> func_ params_ ; \
} \
} \
PR_END_MACRO
NS_IMETHODIMP
nsThread::ProcessNextEvent(bool aMayWait, bool* aResult)
{
LOG(("THRD(%p) ProcessNextEvent [%u %u]\n", this, aMayWait,
mNestedEventLoopDepth));
#if !defined(MOZILLA_XPCOMRT_API)
// If we're on the main thread, we shouldn't be dispatching CPOWs.
if (mIsMainThread == MAIN_THREAD) {
ipc::CancelCPOWs();
}
#endif // !defined(MOZILLA_XPCOMRT_API)
if (NS_WARN_IF(PR_GetCurrentThread() != mThread)) {
return NS_ERROR_NOT_SAME_THREAD;
}
// The toplevel event loop normally blocks waiting for the next event, but
// if we're trying to shut this thread down, we must exit the event loop when
// the event queue is empty.
// This only applys to the toplevel event loop! Nested event loops (e.g.
// during sync dispatch) are waiting for some state change and must be able
// to block even if something has requested shutdown of the thread. Otherwise
// we'll just busywait as we endlessly look for an event, fail to find one,
// and repeat the nested event loop since its state change hasn't happened yet.
bool reallyWait = aMayWait && (mNestedEventLoopDepth > 0 || !ShuttingDown());
#if !defined(MOZILLA_XPCOMRT_API)
if (MAIN_THREAD == mIsMainThread && reallyWait) {
HangMonitor::Suspend();
}
#endif // !defined(MOZILLA_XPCOMRT_API)
// Fire a memory pressure notification, if we're the main thread and one is
// pending.
if (MAIN_THREAD == mIsMainThread && !ShuttingDown()) {
MemoryPressureState mpPending = NS_GetPendingMemoryPressure();
if (mpPending != MemPressure_None) {
nsCOMPtr<nsIObserverService> os = services::GetObserverService();
// Use no-forward to prevent the notifications from being transferred to
// the children of this process.
NS_NAMED_LITERAL_STRING(lowMem, "low-memory-no-forward");
NS_NAMED_LITERAL_STRING(lowMemOngoing, "low-memory-ongoing-no-forward");
if (os) {
os->NotifyObservers(nullptr, "memory-pressure",
mpPending == MemPressure_New ? lowMem.get() :
lowMemOngoing.get());
} else {
NS_WARNING("Can't get observer service!");
}
}
}
#ifdef MOZ_CRASHREPORTER
if (MAIN_THREAD == mIsMainThread && !ShuttingDown()) {
// Keep an eye on memory usage (cheap, ~7ms) somewhat frequently,
// but save memory reports (expensive, ~75ms) less frequently.
const size_t LOW_MEMORY_CHECK_SECONDS = 30;
const size_t LOW_MEMORY_SAVE_SECONDS = 3 * 60;
static TimeStamp nextCheck = TimeStamp::NowLoRes()
+ TimeDuration::FromSeconds(LOW_MEMORY_CHECK_SECONDS);
TimeStamp now = TimeStamp::NowLoRes();
if (now >= nextCheck) {
if (SaveMemoryReportNearOOM()) {
nextCheck = now + TimeDuration::FromSeconds(LOW_MEMORY_SAVE_SECONDS);
} else {
nextCheck = now + TimeDuration::FromSeconds(LOW_MEMORY_CHECK_SECONDS);
}
}
}
#endif
bool notifyMainThreadObserver =
(MAIN_THREAD == mIsMainThread) && sMainThreadObserver;
if (notifyMainThreadObserver) {
sMainThreadObserver->OnProcessNextEvent(this, reallyWait,
mNestedEventLoopDepth);
}
nsCOMPtr<nsIThreadObserver> obs = mObserver;
if (obs) {
obs->OnProcessNextEvent(this, reallyWait, mNestedEventLoopDepth);
}
NOTIFY_EVENT_OBSERVERS(OnProcessNextEvent,
(this, reallyWait, mNestedEventLoopDepth));
++mNestedEventLoopDepth;
#ifdef MOZ_CANARY
Canary canary;
#endif
nsresult rv = NS_OK;
{
// Scope for |event| to make sure that its destructor fires while
// mNestedEventLoopDepth has been incremented, since that destructor can
// also do work.
// If we are shutting down, then do not wait for new events.
nsCOMPtr<nsIRunnable> event;
mEvents->GetEvent(reallyWait, getter_AddRefs(event));
*aResult = (event.get() != nullptr);
if (event) {
LOG(("THRD(%p) running [%p]\n", this, event.get()));
#if !defined(MOZILLA_XPCOMRT_API)
if (MAIN_THREAD == mIsMainThread) {
HangMonitor::NotifyActivity();
}
#endif // !defined(MOZILLA_XPCOMRT_API)
event->Run();
} else if (aMayWait) {
MOZ_ASSERT(ShuttingDown(),
"This should only happen when shutting down");
rv = NS_ERROR_UNEXPECTED;
}
}
--mNestedEventLoopDepth;
NOTIFY_EVENT_OBSERVERS(AfterProcessNextEvent,
(this, mNestedEventLoopDepth, *aResult));
if (obs) {
obs->AfterProcessNextEvent(this, mNestedEventLoopDepth, *aResult);
}
if (notifyMainThreadObserver && sMainThreadObserver) {
sMainThreadObserver->AfterProcessNextEvent(this, mNestedEventLoopDepth,
*aResult);
}
return rv;
}
//-----------------------------------------------------------------------------
// nsISupportsPriority
NS_IMETHODIMP
nsThread::GetPriority(int32_t* aPriority)
{
*aPriority = mPriority;
return NS_OK;
}
NS_IMETHODIMP
nsThread::SetPriority(int32_t aPriority)
{
if (NS_WARN_IF(!mThread)) {
return NS_ERROR_NOT_INITIALIZED;
}
// NSPR defines the following four thread priorities:
// PR_PRIORITY_LOW
// PR_PRIORITY_NORMAL
// PR_PRIORITY_HIGH
// PR_PRIORITY_URGENT
// We map the priority values defined on nsISupportsPriority to these values.
mPriority = aPriority;
PRThreadPriority pri;
if (mPriority <= PRIORITY_HIGHEST) {
pri = PR_PRIORITY_URGENT;
} else if (mPriority < PRIORITY_NORMAL) {
pri = PR_PRIORITY_HIGH;
} else if (mPriority > PRIORITY_NORMAL) {
pri = PR_PRIORITY_LOW;
} else {
pri = PR_PRIORITY_NORMAL;
}
// If chaos mode is active, retain the randomly chosen priority
if (!ChaosMode::isActive(ChaosMode::ThreadScheduling)) {
PR_SetThreadPriority(mThread, pri);
}
return NS_OK;
}
NS_IMETHODIMP
nsThread::AdjustPriority(int32_t aDelta)
{
return SetPriority(mPriority + aDelta);
}
//-----------------------------------------------------------------------------
// nsIThreadInternal
NS_IMETHODIMP
nsThread::GetObserver(nsIThreadObserver** aObs)
{
MutexAutoLock lock(mLock);
NS_IF_ADDREF(*aObs = mObserver);
return NS_OK;
}
NS_IMETHODIMP
nsThread::SetObserver(nsIThreadObserver* aObs)
{
if (NS_WARN_IF(PR_GetCurrentThread() != mThread)) {
return NS_ERROR_NOT_SAME_THREAD;
}
MutexAutoLock lock(mLock);
mObserver = aObs;
return NS_OK;
}
NS_IMETHODIMP
nsThread::GetRecursionDepth(uint32_t* aDepth)
{
if (NS_WARN_IF(PR_GetCurrentThread() != mThread)) {
return NS_ERROR_NOT_SAME_THREAD;
}
*aDepth = mNestedEventLoopDepth;
return NS_OK;
}
NS_IMETHODIMP
nsThread::AddObserver(nsIThreadObserver* aObserver)
{
if (NS_WARN_IF(!aObserver)) {
return NS_ERROR_INVALID_ARG;
}
if (NS_WARN_IF(PR_GetCurrentThread() != mThread)) {
return NS_ERROR_NOT_SAME_THREAD;
}
NS_WARN_IF_FALSE(!mEventObservers.Contains(aObserver),
"Adding an observer twice!");
if (!mEventObservers.AppendElement(aObserver)) {
NS_WARNING("Out of memory!");
return NS_ERROR_OUT_OF_MEMORY;
}
return NS_OK;
}
NS_IMETHODIMP
nsThread::RemoveObserver(nsIThreadObserver* aObserver)
{
if (NS_WARN_IF(PR_GetCurrentThread() != mThread)) {
return NS_ERROR_NOT_SAME_THREAD;
}
if (aObserver && !mEventObservers.RemoveElement(aObserver)) {
NS_WARNING("Removing an observer that was never added!");
}
return NS_OK;
}
NS_IMETHODIMP
nsThread::PushEventQueue(nsIEventTarget** aResult)
{
if (NS_WARN_IF(PR_GetCurrentThread() != mThread)) {
return NS_ERROR_NOT_SAME_THREAD;
}
nsChainedEventQueue* queue = new nsChainedEventQueue();
queue->mEventTarget = new nsNestedEventTarget(this, queue);
{
MutexAutoLock lock(mLock);
queue->mNext = mEvents;
mEvents = queue;
}
NS_ADDREF(*aResult = queue->mEventTarget);
return NS_OK;
}
NS_IMETHODIMP
nsThread::PopEventQueue(nsIEventTarget* aInnermostTarget)
{
if (NS_WARN_IF(PR_GetCurrentThread() != mThread)) {
return NS_ERROR_NOT_SAME_THREAD;
}
if (NS_WARN_IF(!aInnermostTarget)) {
return NS_ERROR_NULL_POINTER;
}
// Don't delete or release anything while holding the lock.
nsAutoPtr<nsChainedEventQueue> queue;
nsRefPtr<nsNestedEventTarget> target;
{
MutexAutoLock lock(mLock);
// Make sure we're popping the innermost event target.
if (NS_WARN_IF(mEvents->mEventTarget != aInnermostTarget)) {
return NS_ERROR_UNEXPECTED;
}
MOZ_ASSERT(mEvents != &mEventsRoot);
queue = mEvents;
mEvents = mEvents->mNext;
nsCOMPtr<nsIRunnable> event;
while (queue->GetEvent(false, getter_AddRefs(event))) {
mEvents->PutEvent(event);
}
// Don't let the event target post any more events.
queue->mEventTarget.swap(target);
target->mQueue = nullptr;
}
return NS_OK;
}
nsresult
nsThread::SetMainThreadObserver(nsIThreadObserver* aObserver)
{
if (aObserver && nsThread::sMainThreadObserver) {
return NS_ERROR_NOT_AVAILABLE;
}
if (!NS_IsMainThread()) {
return NS_ERROR_UNEXPECTED;
}
nsThread::sMainThreadObserver = aObserver;
return NS_OK;
}
//-----------------------------------------------------------------------------
NS_IMETHODIMP
nsThreadSyncDispatch::Run()
{
if (mSyncTask) {
mResult = mSyncTask->Run();
mSyncTask = nullptr;
// unblock the origin thread
mOrigin->Dispatch(this, NS_DISPATCH_NORMAL);
}
return NS_OK;
}
//-----------------------------------------------------------------------------
NS_IMPL_ISUPPORTS(nsThread::nsNestedEventTarget, nsIEventTarget)
NS_IMETHODIMP
nsThread::nsNestedEventTarget::Dispatch(nsIRunnable* aEvent, uint32_t aFlags)
{
LOG(("THRD(%p) Dispatch [%p %x] to nested loop %p\n", mThread.get(), aEvent,
aFlags, this));
return mThread->DispatchInternal(aEvent, aFlags, this);
}
NS_IMETHODIMP
nsThread::nsNestedEventTarget::IsOnCurrentThread(bool* aResult)
{
return mThread->IsOnCurrentThread(aResult);
}
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