1 /* 2 * Copyright (C) 2009 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef SCOPED_FD_H_included 18 #define SCOPED_FD_H_included 19 20 #include <unistd.h> 21 #include "JNIHelp.h" // for DISALLOW_COPY_AND_ASSIGN. 22 23 // A smart pointer that closes the given fd on going out of scope. 24 // Use this when the fd is incidental to the purpose of your function, 25 // but needs to be cleaned up on exit. 26 class ScopedFd { 27 public: ScopedFd(int fd)28 explicit ScopedFd(int fd) : fd_(fd) { 29 } 30 ~ScopedFd()31 ~ScopedFd() { 32 reset(); 33 } 34 get()35 int get() const { 36 return fd_; 37 } 38 release()39 int release() __attribute__((warn_unused_result)) { 40 int localFd = fd_; 41 fd_ = -1; 42 return localFd; 43 } 44 45 void reset(int new_fd = -1) { 46 if (fd_ != -1) { 47 // Even if close(2) fails with EINTR, the fd will have been closed. 48 // Using TEMP_FAILURE_RETRY will either lead to EBADF or closing someone else's fd. 49 // http://lkml.indiana.edu/hypermail/linux/kernel/0509.1/0877.html 50 close(fd_); 51 } 52 fd_ = new_fd; 53 } 54 55 private: 56 int fd_; 57 58 DISALLOW_COPY_AND_ASSIGN(ScopedFd); 59 }; 60 61 #endif // SCOPED_FD_H_included 62