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Diffstat (limited to 'xpcom/threads/ReentrantMonitor.h')
| -rw-r--r-- | xpcom/threads/ReentrantMonitor.h | 251 |
1 files changed, 251 insertions, 0 deletions
diff --git a/xpcom/threads/ReentrantMonitor.h b/xpcom/threads/ReentrantMonitor.h new file mode 100644 index 0000000000..09debad577 --- /dev/null +++ b/xpcom/threads/ReentrantMonitor.h @@ -0,0 +1,251 @@ +/* -*- 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/. */ + +#ifndef mozilla_ReentrantMonitor_h +#define mozilla_ReentrantMonitor_h + +#include "prmon.h" + +#if defined(MOZILLA_INTERNAL_API) && !defined(DEBUG) +# include "mozilla/ProfilerThreadSleep.h" +#endif // defined( MOZILLA_INTERNAL_API) && !defined(DEBUG) + +#include "mozilla/BlockingResourceBase.h" +#include "mozilla/ThreadSafety.h" +#include "nsISupports.h" +// +// Provides: +// +// - ReentrantMonitor, a Java-like monitor +// - ReentrantMonitorAutoEnter, an RAII class for ensuring that +// ReentrantMonitors are properly entered and exited +// +// Using ReentrantMonitorAutoEnter is MUCH preferred to making bare calls to +// ReentrantMonitor.Enter and Exit. +// +namespace mozilla { + +/** + * ReentrantMonitor + * Java-like monitor. + * When possible, use ReentrantMonitorAutoEnter to hold this monitor within a + * scope, instead of calling Enter/Exit directly. + **/ +class MOZ_CAPABILITY("reentrant monitor") ReentrantMonitor + : BlockingResourceBase { + public: + /** + * ReentrantMonitor + * @param aName A name which can reference this monitor + */ + explicit ReentrantMonitor(const char* aName) + : BlockingResourceBase(aName, eReentrantMonitor) +#ifdef DEBUG + , + mEntryCount(0) +#endif + { + MOZ_COUNT_CTOR(ReentrantMonitor); + mReentrantMonitor = PR_NewMonitor(); + if (!mReentrantMonitor) { + MOZ_CRASH("Can't allocate mozilla::ReentrantMonitor"); + } + } + + /** + * ~ReentrantMonitor + **/ + ~ReentrantMonitor() { + NS_ASSERTION(mReentrantMonitor, + "improperly constructed ReentrantMonitor or double free"); + PR_DestroyMonitor(mReentrantMonitor); + mReentrantMonitor = 0; + MOZ_COUNT_DTOR(ReentrantMonitor); + } + +#ifndef DEBUG + /** + * Enter + * @see prmon.h + **/ + void Enter() MOZ_CAPABILITY_ACQUIRE() { PR_EnterMonitor(mReentrantMonitor); } + + /** + * Exit + * @see prmon.h + **/ + void Exit() MOZ_CAPABILITY_RELEASE() { PR_ExitMonitor(mReentrantMonitor); } + + /** + * Wait + * @see prmon.h + **/ + nsresult Wait(PRIntervalTime aInterval = PR_INTERVAL_NO_TIMEOUT) { + PR_ASSERT_CURRENT_THREAD_IN_MONITOR(mReentrantMonitor); +# ifdef MOZILLA_INTERNAL_API + AUTO_PROFILER_THREAD_SLEEP; +# endif // MOZILLA_INTERNAL_API + return PR_Wait(mReentrantMonitor, aInterval) == PR_SUCCESS + ? NS_OK + : NS_ERROR_FAILURE; + } + +#else // ifndef DEBUG + void Enter() MOZ_CAPABILITY_ACQUIRE(); + void Exit() MOZ_CAPABILITY_RELEASE(); + nsresult Wait(PRIntervalTime aInterval = PR_INTERVAL_NO_TIMEOUT); + +#endif // ifndef DEBUG + + /** + * Notify + * @see prmon.h + **/ + nsresult Notify() { + return PR_Notify(mReentrantMonitor) == PR_SUCCESS ? NS_OK + : NS_ERROR_FAILURE; + } + + /** + * NotifyAll + * @see prmon.h + **/ + nsresult NotifyAll() { + return PR_NotifyAll(mReentrantMonitor) == PR_SUCCESS ? NS_OK + : NS_ERROR_FAILURE; + } + +#ifdef DEBUG + /** + * AssertCurrentThreadIn + * @see prmon.h + **/ + void AssertCurrentThreadIn() MOZ_ASSERT_CAPABILITY(this) { + PR_ASSERT_CURRENT_THREAD_IN_MONITOR(mReentrantMonitor); + } + + /** + * AssertNotCurrentThreadIn + * @see prmon.h + **/ + void AssertNotCurrentThreadIn() MOZ_ASSERT_CAPABILITY(!this) { + // FIXME bug 476536 + } + +#else + void AssertCurrentThreadIn() MOZ_ASSERT_CAPABILITY(this) {} + void AssertNotCurrentThreadIn() MOZ_ASSERT_CAPABILITY(!this) {} + +#endif // ifdef DEBUG + + private: + ReentrantMonitor(); + ReentrantMonitor(const ReentrantMonitor&); + ReentrantMonitor& operator=(const ReentrantMonitor&); + + PRMonitor* mReentrantMonitor; +#ifdef DEBUG + int32_t mEntryCount; +#endif +}; + +/** + * ReentrantMonitorAutoEnter + * Enters the ReentrantMonitor when it enters scope, and exits it when + * it leaves scope. + * + * MUCH PREFERRED to bare calls to ReentrantMonitor.Enter and Exit. + */ +class MOZ_SCOPED_CAPABILITY MOZ_STACK_CLASS ReentrantMonitorAutoEnter { + public: + /** + * Constructor + * The constructor aquires the given lock. The destructor + * releases the lock. + * + * @param aReentrantMonitor A valid mozilla::ReentrantMonitor*. + **/ + explicit ReentrantMonitorAutoEnter( + mozilla::ReentrantMonitor& aReentrantMonitor) + MOZ_CAPABILITY_ACQUIRE(aReentrantMonitor) + : mReentrantMonitor(&aReentrantMonitor) { + NS_ASSERTION(mReentrantMonitor, "null monitor"); + mReentrantMonitor->Enter(); + } + + ~ReentrantMonitorAutoEnter(void) MOZ_CAPABILITY_RELEASE() { + mReentrantMonitor->Exit(); + } + + nsresult Wait(PRIntervalTime aInterval = PR_INTERVAL_NO_TIMEOUT) { + return mReentrantMonitor->Wait(aInterval); + } + + nsresult Notify() { return mReentrantMonitor->Notify(); } + nsresult NotifyAll() { return mReentrantMonitor->NotifyAll(); } + + private: + ReentrantMonitorAutoEnter(); + ReentrantMonitorAutoEnter(const ReentrantMonitorAutoEnter&); + ReentrantMonitorAutoEnter& operator=(const ReentrantMonitorAutoEnter&); + static void* operator new(size_t) noexcept(true); + + friend class ReentrantMonitorAutoExit; + + mozilla::ReentrantMonitor* mReentrantMonitor; +}; + +/** + * ReentrantMonitorAutoExit + * Exit the ReentrantMonitor when it enters scope, and enters it when it leaves + * scope. + * + * MUCH PREFERRED to bare calls to ReentrantMonitor.Exit and Enter. + */ +class MOZ_SCOPED_CAPABILITY MOZ_STACK_CLASS ReentrantMonitorAutoExit { + public: + /** + * Constructor + * The constructor releases the given lock. The destructor + * acquires the lock. The lock must be held before constructing + * this object! + * + * @param aReentrantMonitor A valid mozilla::ReentrantMonitor*. It + * must be already locked. + **/ + explicit ReentrantMonitorAutoExit(ReentrantMonitor& aReentrantMonitor) + MOZ_EXCLUSIVE_RELEASE(aReentrantMonitor) + : mReentrantMonitor(&aReentrantMonitor) { + NS_ASSERTION(mReentrantMonitor, "null monitor"); + mReentrantMonitor->AssertCurrentThreadIn(); + mReentrantMonitor->Exit(); + } + + explicit ReentrantMonitorAutoExit( + ReentrantMonitorAutoEnter& aReentrantMonitorAutoEnter) + MOZ_EXCLUSIVE_RELEASE(aReentrantMonitorAutoEnter.mReentrantMonitor) + : mReentrantMonitor(aReentrantMonitorAutoEnter.mReentrantMonitor) { + NS_ASSERTION(mReentrantMonitor, "null monitor"); + mReentrantMonitor->AssertCurrentThreadIn(); + mReentrantMonitor->Exit(); + } + + ~ReentrantMonitorAutoExit(void) MOZ_EXCLUSIVE_RELEASE() { + mReentrantMonitor->Enter(); + } + + private: + ReentrantMonitorAutoExit(); + ReentrantMonitorAutoExit(const ReentrantMonitorAutoExit&); + ReentrantMonitorAutoExit& operator=(const ReentrantMonitorAutoExit&); + static void* operator new(size_t) noexcept(true); + + ReentrantMonitor* mReentrantMonitor; +}; + +} // namespace mozilla + +#endif // ifndef mozilla_ReentrantMonitor_h |