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// -*- mode: c++; c-basic-offset: 4 -*-
/*
* This file is part of the KDE libraries
* Copyright (C) 2005 Apple Computer, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
*/
#ifndef JSLOCK_H
#define JSLOCK_H
#include "global.h"
namespace KJS {
// to make it safe to use JavaScript on multiple threads, it is
// important to lock before doing anything that allocates a
// garbage-collected object or which may affect other shared state
// such as the protect count hash table. The simplest way to do
// this is by having a local JSLock object for the scope
// where the lock must be held. The lock is recursive so nesting
// is ok.
// Sometimes it is necessary to temporarily release the lock -
// since it is recursive you have to actually release all locks
// held by your thread. This is safe to do if you are executing
// code that doesn't require the lock, and reacquire the right
// number of locks at the end. You can do this by constructing a
// locally scoped JSLock::DropAllLocks object.
class KJS_EXPORT JSLock
{
public:
JSLock()
{
lock();
}
~JSLock() {
unlock();
}
static void lock();
static void unlock();
static int lockCount();
class DropAllLocks {
public:
DropAllLocks();
~DropAllLocks();
private:
int m_lockCount;
DropAllLocks(const DropAllLocks&);
DropAllLocks& operator=(const DropAllLocks&);
};
private:
JSLock(const JSLock&);
JSLock& operator=(const JSLock&);
};
#if !USE(MULTIPLE_THREADS)
inline void JSLock::lock() {}
inline void JSLock::unlock() {}
// Fix the lock count at 1 so assertions that the lock is held don't fail
inline int JSLock::lockCount() { return 1; }
#endif
} // namespace
#endif // JSLOCK_H
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