CMake/Source/cmFileLock.h

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Simplify CMake per-source license notices Per-source copyright/license notice headers that spell out copyright holder names and years are hard to maintain and often out-of-date or plain wrong. Precise contributor information is already maintained automatically by the version control tool. Ultimately it is the receiver of a file who is responsible for determining its licensing status, and per-source notices are merely a convenience. Therefore it is simpler and more accurate for each source to have a generic notice of the license name and references to more detailed information on copyright holders and full license terms. Our `Copyright.txt` file now contains a list of Contributors whose names appeared source-level copyright notices. It also references version control history for more precise information. Therefore we no longer need to spell out the list of Contributors in each source file notice. Replace CMake per-source copyright/license notice headers with a short description of the license and links to `Copyright.txt` and online information available from "https://cmake.org/licensing". The online URL also handles cases of modules being copied out of our source into other projects, so we can drop our notices about replacing links with full license text. Run the `Utilities/Scripts/filter-notices.bash` script to perform the majority of the replacements mechanically. Manually fix up shebang lines and trailing newlines in a few files. Manually update the notices in a few files that the script does not handle.
2016-09-27 22:01:08 +03:00
/* Distributed under the OSI-approved BSD 3-Clause License. See accompanying
file Copyright.txt or https://cmake.org/licensing for details. */
#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