gecko-dev/xpcom/glue/nsThreadUtils.cpp
Xidorn Quan 7ba467bc22 Bug 1186745 part 6 - Fix event leak when using NS_DispatchToCurrentThread. r=froydnj
--HG--
extra : source : c8159664670c96e6cfa4c856d6eb14bb9495cd6f
2015-10-06 13:00:59 +11:00

409 lines
9.5 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 "nsThreadUtils.h"
#include "mozilla/Attributes.h"
#include "mozilla/Likely.h"
#include "LeakRefPtr.h"
#ifdef MOZILLA_INTERNAL_API
# include "nsThreadManager.h"
#else
# include "nsXPCOMCIDInternal.h"
# include "nsIThreadManager.h"
# include "nsServiceManagerUtils.h"
#endif
#ifdef XP_WIN
#include <windows.h>
#include "mozilla/WindowsVersion.h"
using mozilla::IsVistaOrLater;
#elif defined(XP_MACOSX)
#include <sys/resource.h>
#endif
#include <pratom.h>
#include <prthread.h>
using namespace mozilla;
#ifndef XPCOM_GLUE_AVOID_NSPR
NS_IMPL_ISUPPORTS(nsRunnable, nsIRunnable)
NS_IMETHODIMP
nsRunnable::Run()
{
// Do nothing
return NS_OK;
}
NS_IMPL_ISUPPORTS(nsCancelableRunnable, nsICancelableRunnable,
nsIRunnable)
NS_IMETHODIMP
nsCancelableRunnable::Run()
{
// Do nothing
return NS_OK;
}
NS_IMETHODIMP
nsCancelableRunnable::Cancel()
{
// Do nothing
return NS_OK;
}
#endif // XPCOM_GLUE_AVOID_NSPR
//-----------------------------------------------------------------------------
NS_METHOD
NS_NewThread(nsIThread** aResult, nsIRunnable* aEvent, uint32_t aStackSize)
{
nsCOMPtr<nsIThread> thread;
#ifdef MOZILLA_INTERNAL_API
nsresult rv =
nsThreadManager::get()->nsThreadManager::NewThread(0, aStackSize,
getter_AddRefs(thread));
#else
nsresult rv;
nsCOMPtr<nsIThreadManager> mgr =
do_GetService(NS_THREADMANAGER_CONTRACTID, &rv);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
rv = mgr->NewThread(0, aStackSize, getter_AddRefs(thread));
#endif
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
if (aEvent) {
rv = thread->Dispatch(aEvent, NS_DISPATCH_NORMAL);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
}
*aResult = nullptr;
thread.swap(*aResult);
return NS_OK;
}
NS_METHOD
NS_GetCurrentThread(nsIThread** aResult)
{
#ifdef MOZILLA_INTERNAL_API
return nsThreadManager::get()->nsThreadManager::GetCurrentThread(aResult);
#else
nsresult rv;
nsCOMPtr<nsIThreadManager> mgr =
do_GetService(NS_THREADMANAGER_CONTRACTID, &rv);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
return mgr->GetCurrentThread(aResult);
#endif
}
NS_METHOD
NS_GetMainThread(nsIThread** aResult)
{
#ifdef MOZILLA_INTERNAL_API
return nsThreadManager::get()->nsThreadManager::GetMainThread(aResult);
#else
nsresult rv;
nsCOMPtr<nsIThreadManager> mgr =
do_GetService(NS_THREADMANAGER_CONTRACTID, &rv);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
return mgr->GetMainThread(aResult);
#endif
}
#ifndef MOZILLA_INTERNAL_API
bool
NS_IsMainThread()
{
bool result = false;
nsCOMPtr<nsIThreadManager> mgr =
do_GetService(NS_THREADMANAGER_CONTRACTID);
if (mgr) {
mgr->GetIsMainThread(&result);
}
return bool(result);
}
#endif
NS_METHOD
NS_DispatchToCurrentThread(already_AddRefed<nsIRunnable>&& aEvent)
{
nsresult rv;
nsCOMPtr<nsIRunnable> event(aEvent);
#ifdef MOZILLA_INTERNAL_API
nsIThread* thread = NS_GetCurrentThread();
if (!thread) {
return NS_ERROR_UNEXPECTED;
}
#else
nsCOMPtr<nsIThread> thread;
rv = NS_GetCurrentThread(getter_AddRefs(thread));
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
#endif
// To keep us from leaking the runnable if dispatch method fails,
// we grab the reference on failures and release it.
nsIRunnable* temp = event.get();
rv = thread->Dispatch(event.forget(), NS_DISPATCH_NORMAL);
if (NS_WARN_IF(NS_FAILED(rv))) {
// Dispatch() leaked the reference to the event, but due to caller's
// assumptions, we shouldn't leak here. And given we are on the same
// thread as the dispatch target, it's mostly safe to do it here.
NS_RELEASE(temp);
}
return rv;
}
// It is common to call NS_DispatchToCurrentThread with a newly
// allocated runnable with a refcount of zero. To keep us from leaking
// the runnable if the dispatch method fails, we take a death grip.
NS_METHOD
NS_DispatchToCurrentThread(nsIRunnable* aEvent)
{
nsCOMPtr<nsIRunnable> event(aEvent);
return NS_DispatchToCurrentThread(event.forget());
}
NS_METHOD
NS_DispatchToMainThread(already_AddRefed<nsIRunnable>&& aEvent, uint32_t aDispatchFlags)
{
LeakRefPtr<nsIRunnable> event(Move(aEvent));
nsCOMPtr<nsIThread> thread;
nsresult rv = NS_GetMainThread(getter_AddRefs(thread));
if (NS_WARN_IF(NS_FAILED(rv))) {
NS_ASSERTION(false, "Failed NS_DispatchToMainThread() in shutdown; leaking");
// NOTE: if you stop leaking here, adjust Promise::MaybeReportRejected(),
// which assumes a leak here, or split into leaks and no-leaks versions
return rv;
}
return thread->Dispatch(event.take(), aDispatchFlags);
}
// In the case of failure with a newly allocated runnable with a
// refcount of zero, we intentionally leak the runnable, because it is
// likely that the runnable is being dispatched to the main thread
// because it owns main thread only objects, so it is not safe to
// release them here.
NS_METHOD
NS_DispatchToMainThread(nsIRunnable* aEvent, uint32_t aDispatchFlags)
{
nsCOMPtr<nsIRunnable> event(aEvent);
return NS_DispatchToMainThread(event.forget(), aDispatchFlags);
}
#ifndef XPCOM_GLUE_AVOID_NSPR
NS_METHOD
NS_ProcessPendingEvents(nsIThread* aThread, PRIntervalTime aTimeout)
{
nsresult rv = NS_OK;
#ifdef MOZILLA_INTERNAL_API
if (!aThread) {
aThread = NS_GetCurrentThread();
if (NS_WARN_IF(!aThread)) {
return NS_ERROR_UNEXPECTED;
}
}
#else
nsCOMPtr<nsIThread> current;
if (!aThread) {
rv = NS_GetCurrentThread(getter_AddRefs(current));
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
aThread = current.get();
}
#endif
PRIntervalTime start = PR_IntervalNow();
for (;;) {
bool processedEvent;
rv = aThread->ProcessNextEvent(false, &processedEvent);
if (NS_FAILED(rv) || !processedEvent) {
break;
}
if (PR_IntervalNow() - start > aTimeout) {
break;
}
}
return rv;
}
#endif // XPCOM_GLUE_AVOID_NSPR
inline bool
hasPendingEvents(nsIThread* aThread)
{
bool val;
return NS_SUCCEEDED(aThread->HasPendingEvents(&val)) && val;
}
bool
NS_HasPendingEvents(nsIThread* aThread)
{
if (!aThread) {
#ifndef MOZILLA_INTERNAL_API
nsCOMPtr<nsIThread> current;
NS_GetCurrentThread(getter_AddRefs(current));
return hasPendingEvents(current);
#else
aThread = NS_GetCurrentThread();
if (NS_WARN_IF(!aThread)) {
return false;
}
#endif
}
return hasPendingEvents(aThread);
}
bool
NS_ProcessNextEvent(nsIThread* aThread, bool aMayWait)
{
#ifdef MOZILLA_INTERNAL_API
if (!aThread) {
aThread = NS_GetCurrentThread();
if (NS_WARN_IF(!aThread)) {
return false;
}
}
#else
nsCOMPtr<nsIThread> current;
if (!aThread) {
NS_GetCurrentThread(getter_AddRefs(current));
if (NS_WARN_IF(!current)) {
return false;
}
aThread = current.get();
}
#endif
bool val;
return NS_SUCCEEDED(aThread->ProcessNextEvent(aMayWait, &val)) && val;
}
#ifndef XPCOM_GLUE_AVOID_NSPR
namespace {
class nsNameThreadRunnable final : public nsIRunnable
{
~nsNameThreadRunnable() {}
public:
explicit nsNameThreadRunnable(const nsACString& aName) : mName(aName) {}
NS_DECL_THREADSAFE_ISUPPORTS
NS_DECL_NSIRUNNABLE
protected:
const nsCString mName;
};
NS_IMPL_ISUPPORTS(nsNameThreadRunnable, nsIRunnable)
NS_IMETHODIMP
nsNameThreadRunnable::Run()
{
PR_SetCurrentThreadName(mName.BeginReading());
return NS_OK;
}
} // namespace
void
NS_SetThreadName(nsIThread* aThread, const nsACString& aName)
{
if (!aThread) {
return;
}
aThread->Dispatch(new nsNameThreadRunnable(aName),
nsIEventTarget::DISPATCH_NORMAL);
}
#else // !XPCOM_GLUE_AVOID_NSPR
void
NS_SetThreadName(nsIThread* aThread, const nsACString& aName)
{
// No NSPR, no love.
}
#endif
#ifdef MOZILLA_INTERNAL_API
nsIThread*
NS_GetCurrentThread()
{
return nsThreadManager::get()->GetCurrentThread();
}
#endif
// nsThreadPoolNaming
void
nsThreadPoolNaming::SetThreadPoolName(const nsACString& aPoolName,
nsIThread* aThread)
{
nsCString name(aPoolName);
name.AppendLiteral(" #");
name.AppendInt(++mCounter, 10); // The counter is declared as volatile
if (aThread) {
// Set on the target thread
NS_SetThreadName(aThread, name);
} else {
// Set on the current thread
#ifndef XPCOM_GLUE_AVOID_NSPR
PR_SetCurrentThreadName(name.BeginReading());
#endif
}
}
// nsAutoLowPriorityIO
nsAutoLowPriorityIO::nsAutoLowPriorityIO()
{
#if defined(XP_WIN)
lowIOPrioritySet = IsVistaOrLater() &&
SetThreadPriority(GetCurrentThread(),
THREAD_MODE_BACKGROUND_BEGIN);
#elif defined(XP_MACOSX)
oldPriority = getiopolicy_np(IOPOL_TYPE_DISK, IOPOL_SCOPE_THREAD);
lowIOPrioritySet = oldPriority != -1 &&
setiopolicy_np(IOPOL_TYPE_DISK,
IOPOL_SCOPE_THREAD,
IOPOL_THROTTLE) != -1;
#else
lowIOPrioritySet = false;
#endif
}
nsAutoLowPriorityIO::~nsAutoLowPriorityIO()
{
#if defined(XP_WIN)
if (MOZ_LIKELY(lowIOPrioritySet)) {
// On Windows the old thread priority is automatically restored
SetThreadPriority(GetCurrentThread(), THREAD_MODE_BACKGROUND_END);
}
#elif defined(XP_MACOSX)
if (MOZ_LIKELY(lowIOPrioritySet)) {
setiopolicy_np(IOPOL_TYPE_DISK, IOPOL_SCOPE_THREAD, oldPriority);
}
#endif
}