CMake/Source/cmFileLock.h

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/*============================================================================
CMake - Cross Platform Makefile Generator
Copyright 2014 Ruslan Baratov
Distributed under the OSI-approved BSD License (the "License");
see accompanying file Copyright.txt for details.
This software is distributed WITHOUT ANY WARRANTY; without even the
implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the License for more information.
============================================================================*/
#ifndef cmFileLock_h
#define cmFileLock_h
#include <cmConfigure.h> // IWYU pragma: keep
#include <string>
#if defined(_WIN32)
#include <windows.h> // HANDLE
#endif
class cmFileLockResult;
/**
* @brief Cross-platform file locking.
* @details Under the hood this class use 'fcntl' for Unix-like platforms and
* 'LockFileEx'/'UnlockFileEx' for Win32 platform. Locks are exclusive and
* advisory.
*/
class cmFileLock
{
public:
cmFileLock();
~cmFileLock();
/**
* @brief Lock the file.
* @param timeoutSec Lock timeout. If -1 try until success or fatal error.
*/
cmFileLockResult Lock(const std::string& filename, unsigned long timeoutSec);
/**
* @brief Unlock the file.
*/
cmFileLockResult Release();
/**
* @brief Check file is locked by this class.
* @details This function helps to find double locks (deadlocks) and to do
* explicit unlocks.
*/
bool IsLocked(const std::string& filename) const;
private:
cmFileLock(const cmFileLock&);
cmFileLock& operator=(const cmFileLock&);
cmFileLockResult OpenFile();
cmFileLockResult LockWithoutTimeout();
cmFileLockResult LockWithTimeout(unsigned long timeoutSec);
#if defined(_WIN32)
typedef HANDLE FileId;
BOOL LockFile(DWORD flags);
#else
typedef int FileId;
int LockFile(int cmd, int type);
#endif
FileId File;
std::string Filename;
};
#endif // cmFileLock_h