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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.
============================================================================*/
#include "cmFileLock.h"
#include <errno.h> // errno
#include <stdio.h> // SEEK_SET
#include <fcntl.h>
#include "cmSystemTools.h"
cmFileLock::cmFileLock(): File(-1)
{
}
cmFileLockResult cmFileLock::Release()
{
if (this->Filename.empty())
{
return cmFileLockResult::MakeOk();
}
const int lockResult = this->LockFile(F_SETLK, F_UNLCK);
this->Filename = "";
if (lockResult == 0)
{
return cmFileLockResult::MakeOk();
}
else
{
return cmFileLockResult::MakeSystem();
}
}
cmFileLockResult cmFileLock::OpenFile()
{
this->File = ::open(this->Filename.c_str(), O_RDWR);
if (this->File == -1)
{
return cmFileLockResult::MakeSystem();
}
else
{
return cmFileLockResult::MakeOk();
}
}
cmFileLockResult cmFileLock::LockWithoutTimeout()
{
if (this->LockFile(F_SETLKW, F_WRLCK) == -1)
{
return cmFileLockResult::MakeSystem();
}
else
{
return cmFileLockResult::MakeOk();
}
}
cmFileLockResult cmFileLock::LockWithTimeout(unsigned long seconds)
{
while (true)
{
if (this->LockFile(F_SETLK, F_WRLCK) == -1)
{
if (errno != EACCES && errno != EAGAIN)
{
return cmFileLockResult::MakeSystem();
}
}
else
{
return cmFileLockResult::MakeOk();
}
if (seconds == 0)
{
return cmFileLockResult::MakeTimeout();
}
--seconds;
cmSystemTools::Delay(1000);
}
}
int cmFileLock::LockFile(int cmd, int type)
{
struct ::flock lock;
lock.l_start = 0;
lock.l_len = 0; // lock all bytes
lock.l_pid = 0; // unused (for F_GETLK only)
lock.l_type = static_cast<short>(type); // exclusive lock
lock.l_whence = SEEK_SET;
return ::fcntl(this->File, cmd, &lock);
}
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