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 final { 27 public: ScopedFd(int fd)28 explicit ScopedFd(int fd) : fd_(fd) { 29 } ScopedFd()30 ScopedFd() : ScopedFd(-1) {} 31 ~ScopedFd()32 ~ScopedFd() { 33 reset(); 34 } 35 ScopedFd(ScopedFd && other)36 ScopedFd(ScopedFd&& other) : fd_(other.release()) {} 37 ScopedFd& operator = (ScopedFd&& s) { 38 reset(s.release()); 39 return *this; 40 } 41 get()42 int get() const { 43 return fd_; 44 } 45 release()46 int release() __attribute__((warn_unused_result)) { 47 int localFd = fd_; 48 fd_ = -1; 49 return localFd; 50 } 51 52 void reset(int new_fd = -1) { 53 if (fd_ != -1) { 54 // Even if close(2) fails with EINTR, the fd will have been closed. 55 // Using TEMP_FAILURE_RETRY will either lead to EBADF or closing someone else's fd. 56 // http://lkml.indiana.edu/hypermail/linux/kernel/0509.1/0877.html 57 close(fd_); 58 } 59 fd_ = new_fd; 60 } 61 62 private: 63 int fd_; 64 65 DISALLOW_COPY_AND_ASSIGN(ScopedFd); 66 }; 67 68 #endif // SCOPED_FD_H_included 69