gecko-dev/xpcom/glue/Monitor.h

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5.9 KiB
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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: sw=4 ts=4 et :
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is mozilla.org code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifndef mozilla_Monitor_h
#define mozilla_Monitor_h
#include "prmon.h"
#include "mozilla/BlockingResourceBase.h"
//
// Provides:
//
// - Monitor, a Java-like monitor
// - MonitorAutoEnter, an RAII class for ensuring that Monitors are properly
// entered and exited
//
// Using MonitorAutoEnter is MUCH preferred to making bare calls to
// Monitor.Enter and Exit.
//
namespace mozilla {
/**
* Monitor
* Java-like monitor.
* When possible, use MonitorAutoEnter to hold this monitor within a
* scope, instead of calling Enter/Exit directly.
**/
class NS_COM_GLUE Monitor : BlockingResourceBase
{
public:
/**
* Monitor
* @param aName A name which can reference this monitor
* @returns If failure, nsnull
* If success, a valid Monitor*, which must be destroyed
* by Monitor::DestroyMonitor()
**/
Monitor(const char* aName) :
BlockingResourceBase(aName, eMonitor)
#ifdef DEBUG
, mEntryCount(0)
#endif
{
mMonitor = PR_NewMonitor();
if (!mMonitor)
NS_RUNTIMEABORT("Can't allocate mozilla::Monitor");
}
/**
* ~Monitor
**/
~Monitor()
{
NS_ASSERTION(mMonitor,
"improperly constructed Monitor or double free");
PR_DestroyMonitor(mMonitor);
mMonitor = 0;
}
#ifndef DEBUG
/**
* Enter
* @see prmon.h
**/
void Enter()
{
PR_EnterMonitor(mMonitor);
}
/**
* Exit
* @see prmon.h
**/
void Exit()
{
PR_ExitMonitor(mMonitor);
}
/**
* Wait
* @see prmon.h
**/
nsresult Wait(PRIntervalTime interval = PR_INTERVAL_NO_TIMEOUT)
{
return PR_Wait(mMonitor, interval) == PR_SUCCESS ?
NS_OK : NS_ERROR_FAILURE;
}
#else
void Enter();
void Exit();
nsresult Wait(PRIntervalTime interval = PR_INTERVAL_NO_TIMEOUT);
#endif // ifndef DEBUG
/**
* Notify
* @see prmon.h
**/
nsresult Notify()
{
return PR_Notify(mMonitor) == PR_SUCCESS
? NS_OK : NS_ERROR_FAILURE;
}
/**
* NotifyAll
* @see prmon.h
**/
nsresult NotifyAll()
{
return PR_NotifyAll(mMonitor) == PR_SUCCESS
? NS_OK : NS_ERROR_FAILURE;
}
#ifdef DEBUG
/**
* AssertCurrentThreadIn
* @see prmon.h
**/
void AssertCurrentThreadIn()
{
PR_ASSERT_CURRENT_THREAD_IN_MONITOR(mMonitor);
}
/**
* AssertNotCurrentThreadIn
* @see prmon.h
**/
void AssertNotCurrentThreadIn()
{
// FIXME bug 476536
}
#else
void AssertCurrentThreadIn()
{
}
void AssertNotCurrentThreadIn()
{
}
#endif // ifdef DEBUG
private:
Monitor();
Monitor(const Monitor&);
Monitor& operator =(const Monitor&);
PRMonitor* mMonitor;
#ifdef DEBUG
PRInt32 mEntryCount;
#endif
};
/**
* MonitorAutoEnter
* Enters the Monitor when it enters scope, and exits it when it leaves
* scope.
*
* MUCH PREFERRED to bare calls to Monitor.Enter and Exit.
*/
class NS_COM_GLUE NS_STACK_CLASS MonitorAutoEnter
{
public:
/**
* Constructor
* The constructor aquires the given lock. The destructor
* releases the lock.
*
* @param aMonitor A valid mozilla::Monitor* returned by
* mozilla::Monitor::NewMonitor.
**/
MonitorAutoEnter(mozilla::Monitor &aMonitor) :
mMonitor(&aMonitor)
{
NS_ASSERTION(mMonitor, "null monitor");
mMonitor->Enter();
}
~MonitorAutoEnter(void)
{
mMonitor->Exit();
}
nsresult Wait(PRIntervalTime interval = PR_INTERVAL_NO_TIMEOUT)
{
return mMonitor->Wait(interval);
}
nsresult Notify()
{
return mMonitor->Notify();
}
nsresult NotifyAll()
{
return mMonitor->NotifyAll();
}
private:
MonitorAutoEnter();
MonitorAutoEnter(const MonitorAutoEnter&);
MonitorAutoEnter& operator =(const MonitorAutoEnter&);
static void* operator new(size_t) CPP_THROW_NEW;
static void operator delete(void*);
mozilla::Monitor* mMonitor;
};
} // namespace mozilla
#endif // ifndef mozilla_Monitor_h