ipc/message_filter.h

   1 // Copyright 2014 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_MESSAGE_FILTER_H_
   6 #define IPC_MESSAGE_FILTER_H_
   7
   8 #include <stdint.h>
   9
  10 #include <vector>
  11
  12 #include "base/memory/ref_counted.h"
  13 #include "ipc/ipc_export.h"
  14
  15 namespace IPC {
  16
  17 class Sender;
  18 class Message;
  19
  20 // A class that receives messages on the thread where the IPC channel is
  21 // running.  It can choose to prevent the default action for an IPC message.
  22 class IPC_EXPORT MessageFilter
  23     : public base::RefCountedThreadSafe<MessageFilter> {
  24  public:
  25   MessageFilter();
  26
  27   // Called on the background thread to provide the filter with access to the
  28   // channel.  Called when the IPC channel is initialized or when AddFilter
  29   // is called if the channel is already initialized.
  30   virtual void OnFilterAdded(Sender* sender);
  31
  32   // Called on the background thread when the filter has been removed from
  33   // the ChannelProxy and when the Channel is closing.  After a filter is
  34   // removed, it will not be called again.
  35   virtual void OnFilterRemoved();
  36
  37   // Called to inform the filter that the IPC channel is connected and we
  38   // have received the internal Hello message from the peer.
  39   virtual void OnChannelConnected(int32_t peer_pid);
  40
  41   // Called when there is an error on the channel, typically that the channel
  42   // has been closed.
  43   virtual void OnChannelError();
  44
  45   // Called to inform the filter that the IPC channel will be destroyed.
  46   // OnFilterRemoved is called immediately after this.
  47   virtual void OnChannelClosing();
  48
  49   // Return true to indicate that the message was handled, or false to let
  50   // the message be handled in the default way.
  51   virtual bool OnMessageReceived(const Message& message);
  52
  53   // Called to query the Message classes supported by the filter.  Return
  54   // false to indicate that all message types should reach the filter, or true
  55   // if the resulting contents of |supported_message_classes| may be used to
  56   // selectively offer messages of a particular class to the filter.
  57   virtual bool GetSupportedMessageClasses(
  58       std::vector<uint32_t>* supported_message_classes) const;
  59
  60  protected:
  61   virtual ~MessageFilter();
  62
  63  private:
  64   friend class base::RefCountedThreadSafe<MessageFilter>;
  65 };
  66
  67 }  // namespace IPC
  68
  69 #endif  // IPC_MESSAGE_FILTER_H_