bdca8b01d2
#pragma once is a widely supported compiler pragma, even though it is not part of the C++ standard. Many of the issues keeping #pragma once from being standardized (distributed filesystems, build farms, hard links, etc.) do not apply to CMake - it is easy to build CMake on a single machine. CMake also does not install any header files which can be consumed by other projects (though cmCPluginAPI.h has been deliberately omitted from this conversion in case anyone is still using it.) Finally, #pragma once has been required to build CMake since at least August 2017 (7f29bbe6enabled server mode unconditionally, which had been using #pragma once since September 2016 (b13d3e0d)). The fact that we now require C++11 filters out old compilers, and it is unlikely that there is a compiler which supports C++11 but does not support #pragma once.
65 lines
1.5 KiB
C++
65 lines
1.5 KiB
C++
/* Distributed under the OSI-approved BSD 3-Clause License. See accompanying
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file Copyright.txt or https://cmake.org/licensing for details. */
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#pragma once
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#include "cmConfigure.h" // IWYU pragma: keep
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#include <string>
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#if defined(_WIN32)
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# include <windows.h> // HANDLE
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#endif
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class cmFileLockResult;
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/**
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* @brief Cross-platform file locking.
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* @details Under the hood this class use 'fcntl' for Unix-like platforms and
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* 'LockFileEx'/'UnlockFileEx' for Win32 platform. Locks are exclusive and
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* advisory.
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*/
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class cmFileLock
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{
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public:
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cmFileLock();
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~cmFileLock();
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cmFileLock(cmFileLock const&) = delete;
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cmFileLock(cmFileLock&&) noexcept;
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cmFileLock& operator=(cmFileLock const&) = delete;
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cmFileLock& operator=(cmFileLock&&) noexcept;
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/**
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* @brief Lock the file.
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* @param timeoutSec Lock timeout. If -1 try until success or fatal error.
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*/
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cmFileLockResult Lock(const std::string& filename, unsigned long timeoutSec);
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/**
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* @brief Unlock the file.
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*/
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cmFileLockResult Release();
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/**
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* @brief Check file is locked by this class.
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* @details This function helps to find double locks (deadlocks) and to do
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* explicit unlocks.
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*/
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bool IsLocked(const std::string& filename) const;
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private:
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cmFileLockResult OpenFile();
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cmFileLockResult LockWithoutTimeout();
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cmFileLockResult LockWithTimeout(unsigned long timeoutSec);
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#if defined(_WIN32)
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HANDLE File = INVALID_HANDLE_VALUE;
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BOOL LockFile(DWORD flags);
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#else
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int File = -1;
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int LockFile(int cmd, int type);
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#endif
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std::string Filename;
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};
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