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// Copyright 2006-2009 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BASE_FILE_DESCRIPTOR_POSIX_H_
#define BASE_FILE_DESCRIPTOR_POSIX_H_
#include "base/base_export.h"
#include "base/files/scoped_file.h"
namespace base {
class File;
constexpr int kInvalidFd = -1;
// -----------------------------------------------------------------------------
// We introduct a special structure for file descriptors in order that we are
// able to use template specialisation to special-case their handling.
//
// IMPORTANT: This is primarily intended for use when sending file descriptors
// over IPC. Even if |auto_close| is true, base::FileDescriptor does NOT close()
// |fd| when going out of scope. Instead, a consumer of a base::FileDescriptor
// must invoke close() on |fd| if |auto_close| is true.
//
// In the case of IPC, the IPC subsystem knows to close() |fd| after sending
// a message that contains a base::FileDescriptor if auto_close == true. On the
// other end, the receiver must make sure to close() |fd| after it has finished
// processing the IPC message. See the IPC::ParamTraits<> specialization in
// ipc/ipc_message_utils.h for all the details.
// -----------------------------------------------------------------------------
struct BASE_EXPORT FileDescriptor {
FileDescriptor();
FileDescriptor(int ifd, bool iauto_close);
explicit FileDescriptor(File file);
explicit FileDescriptor(ScopedFD fd);
friend bool operator==(const FileDescriptor&,
const FileDescriptor&) = default;
// A comparison operator so that we can use these as keys in a std::map.
bool operator<(const FileDescriptor& other) const;
int fd = kInvalidFd;
// If true, this file descriptor should be closed after it has been used. For
// example an IPC system might interpret this flag as indicating that the
// file descriptor it has been given should be closed after use.
bool auto_close = false;
};
} // namespace base
#endif // BASE_FILE_DESCRIPTOR_POSIX_H_
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