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// Copyright (c) 2011 Baidu, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Author: Ge,Jun (gejun@baidu.com)
// Date: Mon. Nov 7 14:47:36 CST 2011
#ifndef BUTIL_FD_GUARD_H
#define BUTIL_FD_GUARD_H
#include <unistd.h> // close()
namespace butil {
// RAII file descriptor.
//
// Example:
// fd_guard fd1(open(...));
// if (fd1 < 0) {
// printf("Fail to open\n");
// return -1;
// }
// if (another-error-happened) {
// printf("Fail to do sth\n");
// return -1; // *** closing fd1 automatically ***
// }
class fd_guard {
public:
fd_guard() : _fd(-1) {}
explicit fd_guard(int fd) : _fd(fd) {}
~fd_guard() {
if (_fd >= 0) {
::close(_fd);
_fd = -1;
}
}
// Close current fd and replace with another fd
void reset(int fd) {
if (_fd >= 0) {
::close(_fd);
_fd = -1;
}
_fd = fd;
}
// Set internal fd to -1 and return the value before set.
int release() {
const int prev_fd = _fd;
_fd = -1;
return prev_fd;
}
operator int() const { return _fd; }
private:
// Copying this makes no sense.
fd_guard(const fd_guard&);
void operator=(const fd_guard&);
int _fd;
};
} // namespace butil
#endif // BUTIL_FD_GUARD_H