1 // Copyright (c) 2006-2009 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef BASE_FILE_DESCRIPTOR_POSIX_H_ 6 #define BASE_FILE_DESCRIPTOR_POSIX_H_ 7 8 #include "base/files/file.h" 9 #include "base/files/scoped_file.h" 10 11 namespace base { 12 13 // ----------------------------------------------------------------------------- 14 // We introduct a special structure for file descriptors in order that we are 15 // able to use template specialisation to special-case their handling. 16 // 17 // IMPORTANT: This is primarily intended for use when sending file descriptors 18 // over IPC. Even if |auto_close| is true, base::FileDescriptor does NOT close() 19 // |fd| when going out of scope. Instead, a consumer of a base::FileDescriptor 20 // must invoke close() on |fd| if |auto_close| is true. 21 // 22 // In the case of IPC, the the IPC subsystem knows to close() |fd| after sending 23 // a message that contains a base::FileDescriptor if auto_close == true. On the 24 // other end, the receiver must make sure to close() |fd| after it has finished 25 // processing the IPC message. See the IPC::ParamTraits<> specialization in 26 // ipc/ipc_message_utils.h for all the details. 27 // ----------------------------------------------------------------------------- 28 struct FileDescriptor { 29 FileDescriptor() : fd(-1), auto_close(false) {} 30 31 FileDescriptor(int ifd, bool iauto_close) : fd(ifd), auto_close(iauto_close) { 32 } 33 34 FileDescriptor(File file) : fd(file.TakePlatformFile()), auto_close(true) {} 35 explicit FileDescriptor(ScopedFD fd) : fd(fd.release()), auto_close(true) {} 36 37 bool operator==(const FileDescriptor& other) const { 38 return (fd == other.fd && auto_close == other.auto_close); 39 } 40 41 bool operator!=(const FileDescriptor& other) const { 42 return !operator==(other); 43 } 44 45 // A comparison operator so that we can use these as keys in a std::map. 46 bool operator<(const FileDescriptor& other) const { 47 return other.fd < fd; 48 } 49 50 int fd; 51 // If true, this file descriptor should be closed after it has been used. For 52 // example an IPC system might interpret this flag as indicating that the 53 // file descriptor it has been given should be closed after use. 54 bool auto_close; 55 }; 56 57 } // namespace base 58 59 #endif // BASE_FILE_DESCRIPTOR_POSIX_H_ 60
