tenfourfox/xpcom/glue/Monitor.h
Cameron Kaiser c9b2922b70 hello FPR
2017-04-19 00:56:45 -07:00

136 lines
3.1 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/. */
#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