From 5f8de423f190bbb79a62f804151bc24824fa32d8 Mon Sep 17 00:00:00 2001 From: "Matt A. Tobin" Date: Fri, 2 Feb 2018 04:16:08 -0500 Subject: Add m-esr52 at 52.6.0 --- xpcom/glue/Monitor.h | 135 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 135 insertions(+) create mode 100644 xpcom/glue/Monitor.h (limited to 'xpcom/glue/Monitor.h') diff --git a/xpcom/glue/Monitor.h b/xpcom/glue/Monitor.h new file mode 100644 index 000000000..60750acb3 --- /dev/null +++ b/xpcom/glue/Monitor.h @@ -0,0 +1,135 @@ +/* -*- 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_Monitor_h +#define mozilla_Monitor_h + +#include "mozilla/CondVar.h" +#include "mozilla/Mutex.h" + +namespace mozilla { + +/** + * Monitor provides a *non*-reentrant monitor: *not* a Java-style + * monitor. If your code needs support for reentrancy, use + * ReentrantMonitor instead. (Rarely should reentrancy be needed.) + * + * Instead of directly calling Monitor methods, it's safer and simpler + * to instead use the RAII wrappers MonitorAutoLock and + * MonitorAutoUnlock. + */ +class Monitor +{ +public: + explicit Monitor(const char* aName) + : mMutex(aName) + , mCondVar(mMutex, "[Monitor.mCondVar]") + { + } + + ~Monitor() {} + + void Lock() { mMutex.Lock(); } + void Unlock() { mMutex.Unlock(); } + + nsresult Wait(PRIntervalTime aInterval = PR_INTERVAL_NO_TIMEOUT) + { + return mCondVar.Wait(aInterval); + } + + nsresult Notify() { return mCondVar.Notify(); } + nsresult NotifyAll() { return mCondVar.NotifyAll(); } + + void AssertCurrentThreadOwns() const + { + mMutex.AssertCurrentThreadOwns(); + } + + void AssertNotCurrentThreadOwns() const + { + mMutex.AssertNotCurrentThreadOwns(); + } + +private: + Monitor(); + Monitor(const Monitor&); + Monitor& operator=(const Monitor&); + + Mutex mMutex; + CondVar mCondVar; +}; + +/** + * Lock the monitor for the lexical scope instances of this class are + * bound to (except for MonitorAutoUnlock in nested scopes). + * + * The monitor must be unlocked when instances of this class are + * created. + */ +class MOZ_STACK_CLASS MonitorAutoLock +{ +public: + explicit MonitorAutoLock(Monitor& aMonitor) + : mMonitor(&aMonitor) + { + mMonitor->Lock(); + } + + ~MonitorAutoLock() + { + mMonitor->Unlock(); + } + + nsresult Wait(PRIntervalTime aInterval = PR_INTERVAL_NO_TIMEOUT) + { + return mMonitor->Wait(aInterval); + } + + nsresult Notify() { return mMonitor->Notify(); } + nsresult NotifyAll() { return mMonitor->NotifyAll(); } + +private: + MonitorAutoLock(); + MonitorAutoLock(const MonitorAutoLock&); + MonitorAutoLock& operator=(const MonitorAutoLock&); + static void* operator new(size_t) CPP_THROW_NEW; + + Monitor* mMonitor; +}; + +/** + * Unlock the monitor for the lexical scope instances of this class + * are bound to (except for MonitorAutoLock in nested scopes). + * + * The monitor must be locked by the current thread when instances of + * this class are created. + */ +class MOZ_STACK_CLASS MonitorAutoUnlock +{ +public: + explicit MonitorAutoUnlock(Monitor& aMonitor) + : mMonitor(&aMonitor) + { + mMonitor->Unlock(); + } + + ~MonitorAutoUnlock() + { + mMonitor->Lock(); + } + +private: + MonitorAutoUnlock(); + MonitorAutoUnlock(const MonitorAutoUnlock&); + MonitorAutoUnlock& operator=(const MonitorAutoUnlock&); + static void* operator new(size_t) CPP_THROW_NEW; + + Monitor* mMonitor; +}; + +} // namespace mozilla + +#endif // mozilla_Monitor_h -- cgit v1.2.3