зеркало из https://github.com/mozilla/gecko-dev.git
117 строки
2.9 KiB
C++
117 строки
2.9 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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*
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* The contents of this file are subject to the Netscape Public License
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* Version 1.0 (the "NPL"); you may not use this file except in
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* compliance with the NPL. You may obtain a copy of the NPL at
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* http://www.mozilla.org/NPL/
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*
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* Software distributed under the NPL is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
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* for the specific language governing rights and limitations under the
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* NPL.
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*
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* The Initial Developer of this code under the NPL is Netscape
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* Communications Corporation. Portions created by Netscape are
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* Copyright (C) 1998 Netscape Communications Corporation. All Rights
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* Reserved.
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*/
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/*
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A stack-based lock object that makes using PRLock a bit more
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convenient. It acquires the monitor when constructed, and releases
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it when it goes out of scope.
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For example,
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class Foo {
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private:
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PRLock* mLock;
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public:
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Foo(void) {
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mLock = PR_NewLock();
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}
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virtual ~Foo(void) {
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PR_DestroyLock(mLock);
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}
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void ThreadSafeMethod(void) {
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// we're don't hold the lock yet...
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nsAutoLock lock(mLock);
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// ...but now we do.
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// we even can do wacky stuff like return from arbitrary places w/o
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// worrying about forgetting to release the lock
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if (some_weird_condition)
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return;
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// otherwise do some other stuff
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}
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void ThreadSafeBlockScope(void) {
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// we're not in the lock here...
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{
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nsAutoLock lock(mLock);
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// but we are now, at least until the block scope closes
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}
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// ...now we're not in the lock anymore
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}
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};
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*/
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#ifndef nsAutoLock_h__
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#define nsAutoLock_h__
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#include "nscore.h"
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#include "prlock.h"
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#include "prlog.h"
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// If you ever decide that you need to add a non-inline method to this
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// class, be sure to change the class declaration to "class NS_BASE
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// nsAutoLock".
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class nsAutoLock {
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private:
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PRLock* mLock;
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// Not meant to be implemented. This makes it a compiler error to
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// construct or assign an nsAutoLock object incorrectly.
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nsAutoLock(void) {}
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nsAutoLock(nsAutoLock& aLock) {}
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nsAutoLock& operator =(nsAutoLock& aLock) {
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return *this;
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}
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// Not meant to be implemented. This makes it a compiler error to
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// attempt to create an nsAutoLock object on the heap.
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static void* operator new(size_t size) {
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return nsnull;
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}
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static void operator delete(void* memory) {}
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public:
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nsAutoLock(PRLock* aLock) : mLock(aLock) {
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PR_ASSERT(mLock);
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// This will assert deep in the bowels of NSPR if you attempt
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// to re-enter the lock.
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PR_Lock(mLock);
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}
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~nsAutoLock(void) {
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PR_Unlock(mLock);
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}
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};
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#endif // nsAutoLock_h__
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