Share PPAPI out-of-process plugins between renderer processes....

chrome/browser/ppapi_plugin_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_BROWSER_PPAPI_PLUGIN_PROCESS_HOST_H_
 #define CHROME_BROWSER_PPAPI_PLUGIN_PROCESS_HOST_H_
 #pragma once
 
+#include <queue>
+
 #include "base/basictypes.h"
 #include "base/file_path.h"
 #include "chrome/browser/browser_child_process_host.h"
 
-class RenderMessageFilter;
-
 class PpapiPluginProcessHost : public BrowserChildProcessHost {
  public:
-  explicit PpapiPluginProcessHost(RenderMessageFilter* filter);
+  class Client {
+   public:
+    // Gets the information about the renderer that's requesting the channel.
+    virtual void GetChannelInfo(base::ProcessHandle* renderer_handle,
+                                int* renderer_id) = 0;
+
+    // Called when the channel is asynchronously opened to the plugin or on
+    // error. On error, the parameters should be:
+    //   base::kNullProcessHandle
+    //   IPC::ChannelHandle()
+    virtual void OnChannelOpened(base::ProcessHandle plugin_process_handle,
+                                 const IPC::ChannelHandle& channel_handle) = 0;
+  };
+
+  // You must call init before doing anything else.
+  explicit PpapiPluginProcessHost();
   virtual ~PpapiPluginProcessHost();
 
-  void Init(const FilePath& path, IPC::Message* reply_msg);
+  // Actually launches the process with the given plugin path. Returns true
+  // on success (the process was spawned).
+  bool Init(const FilePath& path);
+
+  // Opens a new channel to the plugin. The client will be notified when the
+  // channel is ready or if there's an error.
+  void OpenChannelToPlugin(Client* client);
+
+  const FilePath& plugin_path() const { return plugin_path_; }
+
+  // The client pointer must remain valid until its callback is issued.
 
  private:
+
+  void RequestPluginChannel(Client* client);
+
   virtual bool CanShutdown();
   virtual void OnProcessLaunched();
 
   virtual bool OnMessageReceived(const IPC::Message& msg);
   virtual void OnChannelConnected(int32 peer_pid);
   virtual void OnChannelError();
 
+  void CancelRequests();
+
   // IPC message handlers.
-  void OnPluginLoaded(const IPC::ChannelHandle& handle);
+  void OnRendererPluginChannelCreated(const IPC::ChannelHandle& handle);
 
-  // Sends the reply_msg_ to the renderer with the given channel info.
-  void ReplyToRenderer(base::ProcessHandle plugin_handle,
-                       const IPC::ChannelHandle& channel_handle);
+  // Channel requests that we are waiting to send to the plugin process once
+  // the channel is opened.
+  std::vector<Client*> pending_requests_;
 
-  RenderMessageFilter* filter_;
+  // Channel requests that we have already sent to the plugin process, but
+  // haven't heard back about yet.
+  std::queue<Client*> sent_requests_;
 
   // Path to the plugin library.
   FilePath plugin_path_;
 
-  // When we're waiting for initialization of the plugin, this contains the
-  // reply message for the renderer to tell it that it can continue.
-  scoped_ptr<IPC::Message> reply_msg_;
-
   DISALLOW_COPY_AND_ASSIGN(PpapiPluginProcessHost);
 };
 
 #endif  // CHROME_BROWSER_PPAPI_PLUGIN_PROCESS_HOST_H_