summaryrefslogtreecommitdiffstats
path: root/chrome/common/child_process_host.h
blob: 6e1725e919f8ce9e872dd5556a5dac6b12654957 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
// Copyright (c) 2009 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CHROME_COMMON_CHILD_PROCESS_HOST_H_
#define CHROME_COMMON_CHILD_PROCESS_HOST_H_

#include <list>
#include <string>

// Must be included early (e.g. before chrome/common/plugin_messages.h)
#include "ipc/ipc_logging.h"

#include "base/basictypes.h"
#include "base/scoped_ptr.h"
#include "chrome/browser/renderer_host/resource_dispatcher_host.h"
#include "ipc/ipc_channel.h"

class CommandLine;
class NotificationType;

// Plugins/workers and other child processes that live on the IO thread should
// derive from this class.
//
// [Browser]RenderProcessHost is the main exception that doesn't derive from
// this class. That project lives on the UI thread.
class ChildProcessHost : public ResourceDispatcherHost::Receiver,
                         public IPC::Channel::Listener {
 public:
  virtual ~ChildProcessHost();

  // Returns the pathname to be used for a child process.  If a subprocess
  // pathname was specified on the command line, that will be used.  Otherwise,
  // the default child process pathname will be returned.  On most platforms,
  // this will be the same as the currently-executing process.  On failure,
  // returns an empty wstring.
  static FilePath GetChildPath();

  // Prepares command_line for crash reporting as appropriate.  On Linux and
  // Mac, a command-line flag to enable crash reporting in the child process
  // will be appended if needed, because the child process may not have access
  // to the data that determines the status of crash reporting in the
  // currently-executing process.  This function is a no-op on Windows.
  static void SetCrashReporterCommandLine(CommandLine* command_line);

  // ResourceDispatcherHost::Receiver implementation:
  virtual bool Send(IPC::Message* msg);

  // The Iterator class allows iteration through either all child processes, or
  // ones of a specific type, depending on which constructor is used.  Note that
  // this should be done from the IO thread and that the iterator should not be
  // kept around as it may be invalidated on subsequent event processing in the
  // event loop.
  class Iterator {
   public:
    Iterator();
    Iterator(ProcessType type);
    ChildProcessHost* operator->() { return *iterator_; }
    ChildProcessHost* operator*() { return *iterator_; }
    ChildProcessHost* operator++();
    bool Done();

   private:
    bool all_;
    ProcessType type_;
    std::list<ChildProcessHost*>::iterator iterator_;
  };

 protected:
  ChildProcessHost(ProcessType type,
                   ResourceDispatcherHost* resource_dispatcher_host);

  // Derived classes return true if it's ok to shut down the child process.
  virtual bool CanShutdown() = 0;

  // Creates the IPC channel.  Returns true iff it succeeded.
  bool CreateChannel();

  // Once the subclass gets a handle to the process, it needs to tell
  // ChildProcessHost using this function.
  void SetHandle(base::ProcessHandle handle);

  // Notifies us that an instance has been created on this child process.
  void InstanceCreated();

  // IPC::Channel::Listener implementation:
  virtual void OnMessageReceived(const IPC::Message& msg) { }
  virtual void OnChannelConnected(int32 peer_pid) { }
  virtual void OnChannelError() { }

  bool opening_channel() { return opening_channel_; }
  const std::string& channel_id() { return channel_id_; }

  const IPC::Channel& channel() const { return *channel_; }

 private:
  // Sends the given notification to the notification service on the UI thread.
  void Notify(NotificationType type);

  // Called when the child process goes away.
  void OnChildDied();

  // By using an internal class as the IPC::Channel::Listener, we can intercept
  // OnMessageReceived/OnChannelConnected and do our own processing before
  // calling the subclass' implementation.
  class ListenerHook : public IPC::Channel::Listener {
   public:
    ListenerHook(ChildProcessHost* host);
    virtual void OnMessageReceived(const IPC::Message& msg);
    virtual void OnChannelConnected(int32 peer_pid);
    virtual void OnChannelError();
   private:
    ChildProcessHost* host_;
  };

  ListenerHook listener_;

  ResourceDispatcherHost* resource_dispatcher_host_;

  // True while we're waiting the channel to be opened.
  bool opening_channel_;

  // The IPC::Channel.
  scoped_ptr<IPC::Channel> channel_;

  // IPC Channel's id.
  std::string channel_id_;
};

#endif  // CHROME_COMMON_CHILD_PROCESS_HOST_H_