Create a ResourceMessageFilter to filter resource related IPCs. This gets ri...

chrome/common/child_process_host.h

 // Copyright (c) 2010 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_
 #pragma once
 
 #include <string>
+#include <vector>
 
 #include "build/build_config.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #endif  // defined(OS_WIN)
 
 #include "base/basictypes.h"
 #include "base/scoped_ptr.h"
 #include "chrome/common/notification_type.h"
-#include "ipc/ipc_channel.h"
+#include "ipc/ipc_channel_proxy.h"
 
 class CommandLine;
 class FilePath;
 
 namespace IPC {
 class Message;
 }
 
 // Provides common functionality for hosting a child process and processing IPC
 // messages between the host and the child process. Subclasses are responsible
 // for the actual launching and terminating of the child processes.
-//
-class ChildProcessHost : public IPC::Channel::Listener {
+class ChildProcessHost : public IPC::Channel::Listener,
+                         public IPC::Message::Sender {
  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.
   //
   // The argument allow_self is used on Linux to indicate that we allow us to
   // fork from /proc/self/exe rather than using the "real" app path. This
   // prevents autoupdate from confusing us if it changes the file out from
   // under us. You will generally want to set this to true, except when there
   // is an override to the command line (for example, we're forking a renderer
   // in gdb). In this case, you'd use GetChildPath to get the real executable
   // file name, and then prepend the GDB command to the command line.
   //
   // On failure, returns an empty FilePath.
   static FilePath GetChildPath(bool allow_self);
 
 #if defined(OS_WIN)
   // See comments in the cc file. This is a common hack needed for a process
   // hosting a sandboxed child process. Hence it lives in this file.
   static void PreCacheFont(LOGFONT font);
 #endif  // defined(OS_WIN)
 
+  // IPC::Message::Sender implementation.
+  bool Send(IPC::Message* message);
+
  protected:
   ChildProcessHost();
 
-  // A helper method to send an IPC message to the child on the channel.
-  // It behavies just like IPC::Message::Sender::Send. The implementor takes
-  // ownership of the given Message regardless of whether or not this method
-  // succeeds. This class does not implement IPC::Message::Sender to prevent
-  // conflicts with subclasses which indirectly could inherit from
-  // IPC::Message::Sender.
-  bool SendOnChannel(IPC::Message* msg);
+  // Adds an IPC message filter.
+  void AddFilter(IPC::ChannelProxy::MessageFilter* filter);

[brettw, 2010/12/15 21:31:10]

Can you make explicit that this takes a reference to the given filter?

[jam, 2010/12/15 21:41:04]

Done.

 
   // Derived classes return true if it's ok to shut down the child process.
   virtual bool CanShutdown() = 0;
 
   // Send the shutdown message to the child process.
   // Does not check if CanShutdown is true.
   virtual void ForceShutdown();
 
   // Creates the IPC channel.  Returns true iff it succeeded.
   virtual bool CreateChannel();
 
   // Notifies us that an instance has been created on this child process.
   virtual 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_; }
   IPC::Channel* channel() { return channel_.get(); }
 
   // Called when the child process goes away.
   virtual void OnChildDied();
-  // Allows the derived implementation to intercept a message before it is
-  // handed to the IPC::Channel::Listener::OnMessageReceived implementation.
-  virtual bool InterceptMessageFromChild(const IPC::Message& msg);
+  // Notifies the derived class that we told the child process to kill itself.
+  virtual void ShutdownStarted() { }
   // Subclasses can implement specific notification methods.
   virtual void Notify(NotificationType type) { }
 
  private:
   // 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:
     explicit ListenerHook(ChildProcessHost* host);
     virtual void OnMessageReceived(const IPC::Message& msg);
     virtual void OnChannelConnected(int32 peer_pid);
     virtual void OnChannelError();
    private:
     ChildProcessHost* host_;
   };
 
   ListenerHook listener_;
 
   bool opening_channel_;  // True while we're waiting the channel to be opened.
   scoped_ptr<IPC::Channel> channel_;
   std::string channel_id_;
 
+  // Holds all the IPC message filters.  Since this object lives on the IO
+  // thread, we don't have a IPC::ChannelProxy and so we manage filters
+  // manually.
+  std::vector<scoped_refptr<IPC::ChannelProxy::MessageFilter> > filters_;
+
   DISALLOW_COPY_AND_ASSIGN(ChildProcessHost);
 };
 
 #endif  // CHROME_COMMON_CHILD_PROCESS_HOST_H_