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//
// FileStreamRWLock_WIN32.h
//
// Library: Foundation
// Package: Processes
// Module: FileStreamRWLock
//
// Definition of the FileStreamRWLockImpl class for WIN32 FileStream.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
#ifndef Foundation_FileStreamRWLock_WIN32_INCLUDED
#define Foundation_FileStreamRWLock_WIN32_INCLUDED
#include "Poco/Foundation.h"
#include "Poco/Exception.h"
#include "Poco/FileStream.h"
#include <Windows.h>
namespace Poco {
struct LockMode
{
static constexpr DWORD READ = 0;
static constexpr DWORD WRITE = LOCKFILE_EXCLUSIVE_LOCK;
static constexpr DWORD TRY_READ = LOCKFILE_FAIL_IMMEDIATELY;
static constexpr DWORD TRY_WRITE = (LOCKFILE_EXCLUSIVE_LOCK | LOCKFILE_FAIL_IMMEDIATELY);
};
class Foundation_API FileStreamRWLockImpl
{
protected:
FileStreamRWLockImpl(const FileStream::NativeHandle &fd, Poco::UInt64 offset, Poco::UInt64 size);
~FileStreamRWLockImpl();
void readLockImpl();
bool tryReadLockImpl();
void writeLockImpl();
bool tryWriteLockImpl();
void unlockImpl();
private:
FileStream::NativeHandle _fd;
OVERLAPPED _overlapped;
LARGE_INTEGER _size;
};
//
// inlines
//
inline void FileStreamRWLockImpl::readLockImpl()
{
BOOL fSuccess = LockFileEx(_fd, LockMode::READ, 0, _size.LowPart, _size.HighPart, &_overlapped);
if (!fSuccess)
{
throw SystemException("cannot lock reader lock", GetLastError());
}
}
inline bool FileStreamRWLockImpl::tryReadLockImpl()
{
BOOL fSuccess = LockFileEx(_fd, LockMode::TRY_READ, 0, _size.LowPart, _size.HighPart, &_overlapped);
if (fSuccess)
{
return true;
}
else
{
auto lastError = GetLastError();
if (lastError == ERROR_IO_PENDING || lastError == ERROR_LOCK_VIOLATION)
{
return false;
}
else
{
throw SystemException("cannot lock try-reader lock", lastError);
}
}
}
inline void FileStreamRWLockImpl::writeLockImpl()
{
BOOL fSuccess = LockFileEx(_fd, LockMode::WRITE, 0, _size.LowPart, _size.HighPart, &_overlapped);
if (!fSuccess)
{
throw SystemException("cannot lock writer lock", GetLastError());
}
}
inline bool FileStreamRWLockImpl::tryWriteLockImpl()
{
BOOL fSuccess = LockFileEx(_fd, LockMode::TRY_WRITE, 0, _size.LowPart, _size.HighPart, &_overlapped);
if (fSuccess)
{
return true;
}
else
{
auto lastError = GetLastError();
if (lastError == ERROR_IO_PENDING || lastError == ERROR_LOCK_VIOLATION)
{
return false;
}
else
{
throw SystemException("cannot lock try-writer lock", lastError);
}
}
}
inline void FileStreamRWLockImpl::unlockImpl()
{
BOOL fSuccess = UnlockFileEx(_fd, 0, _size.LowPart, _size.HighPart, &_overlapped);
if (!fSuccess)
{
throw SystemException("cannot unlock ", GetLastError());
}
}
} // namespace Poco
#endif // Foundation_FileStreamRWLock_WIN32_INCLUDED
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