f048872e91
migrating talk/base to webrtc/base. BUG=N/A R=niklas.enbom@webrtc.org Review URL: https://webrtc-codereview.appspot.com/17479005 git-svn-id: http://webrtc.googlecode.com/svn/trunk@6129 4adac7df-926f-26a2-2b94-8c16560cd09d
54 lines
1.5 KiB
C++
54 lines
1.5 KiB
C++
/*
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* Copyright 2009 The WebRTC Project Authors. All rights reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef WEBRTC_BASE_FILELOCK_H_
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#define WEBRTC_BASE_FILELOCK_H_
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#include <string>
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#include "webrtc/base/constructormagic.h"
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#include "webrtc/base/scoped_ptr.h"
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namespace rtc {
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class FileStream;
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// Implements a very simple cross process lock based on a file.
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// When Lock(...) is called we try to open/create the file in read/write
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// mode without any sharing. (Or locking it with flock(...) on Unix)
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// If the process crash the OS will make sure that the file descriptor
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// is released and another process can accuire the lock.
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// This doesn't work on ancient OSX/Linux versions if used on NFS.
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// (Nfs-client before: ~2.6 and Linux Kernel < 2.6.)
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class FileLock {
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public:
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virtual ~FileLock();
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// Attempts to lock the file. The caller owns the returned
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// lock object. Returns NULL if the file already was locked.
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static FileLock* TryLock(const std::string& path);
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void Unlock();
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protected:
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FileLock(const std::string& path, FileStream* file);
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private:
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void MaybeUnlock();
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std::string path_;
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scoped_ptr<FileStream> file_;
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DISALLOW_EVIL_CONSTRUCTORS(FileLock);
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};
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} // namespace rtc
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#endif // WEBRTC_BASE_FILELOCK_H_
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