gecko/xpcom/glue/Monitor.h

159 lines
3.4 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: sw=2 ts=8 et :
*/
/* 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 NS_COM_GLUE Monitor
{
public:
Monitor(const char* aName) :
mMutex(aName),
mCondVar(mMutex, "[Monitor.mCondVar]")
{}
~Monitor() {}
void Lock()
{
mMutex.Lock();
}
void Unlock()
{
mMutex.Unlock();
}
nsresult Wait(PRIntervalTime interval = PR_INTERVAL_NO_TIMEOUT)
{
return mCondVar.Wait(interval);
}
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 NS_COM_GLUE MOZ_STACK_CLASS MonitorAutoLock
{
public:
MonitorAutoLock(Monitor& aMonitor) :
mMonitor(&aMonitor)
{
mMonitor->Lock();
}
~MonitorAutoLock()
{
mMonitor->Unlock();
}
nsresult Wait(PRIntervalTime interval = PR_INTERVAL_NO_TIMEOUT)
{
return mMonitor->Wait(interval);
}
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;
static void operator delete(void*);
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 NS_COM_GLUE MOZ_STACK_CLASS MonitorAutoUnlock
{
public:
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;
static void operator delete(void*);
Monitor* mMonitor;
};
} // namespace mozilla
#endif // mozilla_Monitor_h