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