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