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