ipc/ipc_channel_handle.h

   1 // Copyright (c) 2012 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 IPC_IPC_CHANNEL_HANDLE_H_
   6 #define IPC_IPC_CHANNEL_HANDLE_H_
   7 #pragma once
   8
   9 #include <string>
  10
  11 #include "build/build_config.h"
  12
  13 #if defined(OS_POSIX)
  14 #include "base/file_descriptor_posix.h"
  15 #elif defined(OS_WIN)
  16 #include <windows.h>
  17 #endif  // defined (OS_WIN)
  18
  19 // On Windows, any process can create an IPC channel and others can fetch
  20 // it by name.  We pass around the channel names over IPC.
  21 // On Windows the initialization of ChannelHandle with an existing pipe
  22 // handle is provided for convenience.
  23 // NOTE: A ChannelHandle with a pipe handle Will NOT be marshalled over IPC.
  24
  25 // On POSIX, we instead pass around handles to channel endpoints via IPC.
  26 // When it's time to IPC a new channel endpoint around, we send both the
  27 // channel name as well as a base::FileDescriptor, which is itself a special
  28 // type that knows how to copy a socket endpoint over IPC.
  29 //
  30 // In sum, this data structure can be used to pass channel information by name
  31 // in both Windows and Posix. When passing a handle to a channel over IPC,
  32 // use this data structure only for POSIX.
  33
  34 namespace IPC {
  35
  36 struct ChannelHandle {
  37   // Note that serialization for this object is defined in the ParamTraits
  38   // template specialization in ipc_message_utils.h.
  39   ChannelHandle() {}
  40   // The name that is passed in should be an absolute path for Posix.
  41   // Otherwise there may be a problem in IPC communication between
  42   // processes with different working directories.
  43   ChannelHandle(const std::string& n) : name(n) {}
  44   ChannelHandle(const char* n) : name(n) {}
  45 #if defined(OS_WIN)
  46   explicit ChannelHandle(HANDLE h) : pipe(h) {}
  47 #elif defined(OS_POSIX)
  48   ChannelHandle(const std::string& n, const base::FileDescriptor& s)
  49       : name(n), socket(s) {}
  50 #endif  // defined(OS_POSIX)
  51
  52   std::string name;
  53 #if defined(OS_POSIX)
  54   base::FileDescriptor socket;
  55 #elif defined(OS_WIN)
  56   // A simple container to automatically initialize pipe handle
  57   struct PipeHandle {
  58     PipeHandle() : handle(NULL) {}
  59     PipeHandle(HANDLE h) : handle(h) {}
  60     HANDLE handle;
  61   };
  62   PipeHandle pipe;
  63 #endif  // defined (OS_WIN)
  64 };
  65
  66 }  // namespace IPC
  67
  68 #endif  // IPC_IPC_CHANNEL_HANDLE_H_