mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-12-05 20:15:58 +00:00
239 lines
6.4 KiB
C++
239 lines
6.4 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
|
|
*
|
|
* The contents of this file are subject to the Netscape Public License
|
|
* Version 1.0 (the "NPL"); you may not use this file except in
|
|
* compliance with the NPL. You may obtain a copy of the NPL at
|
|
* http://www.mozilla.org/NPL/
|
|
*
|
|
* Software distributed under the NPL is distributed on an "AS IS" basis,
|
|
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
|
|
* for the specific language governing rights and limitations under the
|
|
* NPL.
|
|
*
|
|
* The Initial Developer of this code under the NPL is Netscape
|
|
* Communications Corporation. Portions created by Netscape are
|
|
* Copyright (C) 1998 Netscape Communications Corporation. All Rights
|
|
* Reserved.
|
|
*/
|
|
|
|
|
|
/*
|
|
|
|
A stack-based lock object that makes using PRLock a bit more
|
|
convenient. It acquires the monitor when constructed, and releases
|
|
it when it goes out of scope.
|
|
|
|
For example,
|
|
|
|
class Foo {
|
|
private:
|
|
PRLock* mLock;
|
|
|
|
public:
|
|
Foo(void) {
|
|
mLock = PR_NewLock();
|
|
}
|
|
|
|
virtual ~Foo(void) {
|
|
PR_DestroyLock(mLock);
|
|
}
|
|
|
|
void ThreadSafeMethod(void) {
|
|
// we're don't hold the lock yet...
|
|
|
|
nsAutoLock lock(mLock);
|
|
// ...but now we do.
|
|
|
|
// we even can do wacky stuff like return from arbitrary places w/o
|
|
// worrying about forgetting to release the lock
|
|
if (some_weird_condition)
|
|
return;
|
|
|
|
// otherwise do some other stuff
|
|
}
|
|
|
|
void ThreadSafeBlockScope(void) {
|
|
// we're not in the lock here...
|
|
|
|
{
|
|
nsAutoLock lock(mLock);
|
|
// but we are now, at least until the block scope closes
|
|
}
|
|
|
|
// ...now we're not in the lock anymore
|
|
}
|
|
};
|
|
|
|
*/
|
|
|
|
#ifndef nsAutoLock_h__
|
|
#define nsAutoLock_h__
|
|
|
|
#include "nscore.h"
|
|
#include "prlock.h"
|
|
#include "prlog.h"
|
|
|
|
// If you ever decide that you need to add a non-inline method to this
|
|
// class, be sure to change the class declaration to "class NS_COM
|
|
// nsAutoLock".
|
|
|
|
class nsAutoLock {
|
|
private:
|
|
PRLock* mLock;
|
|
|
|
// Not meant to be implemented. This makes it a compiler error to
|
|
// construct or assign an nsAutoLock object incorrectly.
|
|
nsAutoLock(void) {}
|
|
nsAutoLock(nsAutoLock& aLock) {}
|
|
nsAutoLock& operator =(nsAutoLock& aLock) {
|
|
return *this;
|
|
}
|
|
|
|
// Not meant to be implemented. This makes it a compiler error to
|
|
// attempt to create an nsAutoLock object on the heap.
|
|
static void* operator new(size_t size) {
|
|
return nsnull;
|
|
}
|
|
static void operator delete(void* memory) {}
|
|
|
|
public:
|
|
nsAutoLock(PRLock* aLock) : mLock(aLock) {
|
|
PR_ASSERT(mLock);
|
|
|
|
// This will assert deep in the bowels of NSPR if you attempt
|
|
// to re-enter the lock.
|
|
PR_Lock(mLock);
|
|
}
|
|
|
|
~nsAutoLock(void) {
|
|
PR_Unlock(mLock);
|
|
}
|
|
};
|
|
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
// Same sort of shit here. Imagine if you will:
|
|
//
|
|
// nsresult MyClass::MyMethod(...) {
|
|
// nsAutoMonitor mon(this); // or some random object as a monitor
|
|
// ...
|
|
// // go ahead and do deeply nested returns...
|
|
// return NS_ERROR_FAILURE;
|
|
// ...
|
|
// // or call Wait or Notify...
|
|
// mon.Wait();
|
|
// ...
|
|
// // cleanup is automatic
|
|
// }
|
|
|
|
#include "prcmon.h"
|
|
#include "nsError.h"
|
|
|
|
class nsAutoMonitor {
|
|
public:
|
|
nsAutoMonitor(PRMonitor* mon)
|
|
: mMonitor(mon)
|
|
{
|
|
NS_ASSERTION(mMonitor, "null lock object");
|
|
PR_EnterMonitor(mMonitor);
|
|
}
|
|
|
|
~nsAutoMonitor() {
|
|
PRStatus status;
|
|
status = PR_ExitMonitor(mMonitor);
|
|
NS_ASSERTION(status == PR_SUCCESS, "PR_CExitMonitor failed");
|
|
}
|
|
|
|
nsresult Wait(PRIntervalTime interval = PR_INTERVAL_NO_TIMEOUT) {
|
|
return PR_Wait(mMonitor, interval) == PR_SUCCESS
|
|
? NS_OK : NS_ERROR_FAILURE;
|
|
}
|
|
|
|
nsresult Notify() {
|
|
return PR_Notify(mMonitor) == PR_SUCCESS
|
|
? NS_OK : NS_ERROR_FAILURE;
|
|
}
|
|
|
|
nsresult NotifyAll() {
|
|
return PR_NotifyAll(mMonitor) == PR_SUCCESS
|
|
? NS_OK : NS_ERROR_FAILURE;
|
|
}
|
|
|
|
private:
|
|
PRMonitor* mMonitor;
|
|
|
|
// Not meant to be implemented. This makes it a compiler error to
|
|
// construct or assign an nsAutoLock object incorrectly.
|
|
nsAutoMonitor(void) {}
|
|
nsAutoMonitor(nsAutoMonitor& aMon) {}
|
|
nsAutoMonitor& operator =(nsAutoMonitor& aMon) {
|
|
return *this;
|
|
}
|
|
|
|
// Not meant to be implemented. This makes it a compiler error to
|
|
// attempt to create an nsAutoLock object on the heap.
|
|
static void* operator new(size_t size) {
|
|
return nsnull;
|
|
}
|
|
static void operator delete(void* memory) {}
|
|
};
|
|
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
// Once again, this time with a cache...
|
|
// (Using this avoids the need to allocate a PRMonitor, which may be useful when
|
|
// a large number of objects of the same class need associated monitors.)
|
|
|
|
#include "prcmon.h"
|
|
#include "nsError.h"
|
|
|
|
class nsAutoCMonitor {
|
|
public:
|
|
nsAutoCMonitor(void* lockObject)
|
|
: mLockObject(lockObject)
|
|
{
|
|
NS_ASSERTION(lockObject, "null lock object");
|
|
PR_CEnterMonitor(mLockObject);
|
|
}
|
|
|
|
~nsAutoCMonitor() {
|
|
PRStatus status;
|
|
status = PR_CExitMonitor(mLockObject);
|
|
NS_ASSERTION(status == PR_SUCCESS, "PR_CExitMonitor failed");
|
|
}
|
|
|
|
nsresult Wait(PRIntervalTime interval = PR_INTERVAL_NO_TIMEOUT) {
|
|
return PR_CWait(mLockObject, interval) == PR_SUCCESS
|
|
? NS_OK : NS_ERROR_FAILURE;
|
|
}
|
|
|
|
nsresult Notify() {
|
|
return PR_CNotify(mLockObject) == PR_SUCCESS
|
|
? NS_OK : NS_ERROR_FAILURE;
|
|
}
|
|
|
|
nsresult NotifyAll() {
|
|
return PR_CNotifyAll(mLockObject) == PR_SUCCESS
|
|
? NS_OK : NS_ERROR_FAILURE;
|
|
}
|
|
|
|
private:
|
|
void* mLockObject;
|
|
|
|
// Not meant to be implemented. This makes it a compiler error to
|
|
// construct or assign an nsAutoLock object incorrectly.
|
|
nsAutoCMonitor(void) {}
|
|
nsAutoCMonitor(nsAutoCMonitor& aMon) {}
|
|
nsAutoCMonitor& operator =(nsAutoCMonitor& aMon) {
|
|
return *this;
|
|
}
|
|
|
|
// Not meant to be implemented. This makes it a compiler error to
|
|
// attempt to create an nsAutoLock object on the heap.
|
|
static void* operator new(size_t size) {
|
|
return nsnull;
|
|
}
|
|
static void operator delete(void* memory) {}
|
|
};
|
|
|
|
#endif // nsAutoLock_h__
|
|
|