render_frame_proxy_host.h revision cedac228d2dd51db4b79ea1e72c7f249408ee061 
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 CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_PROXY_HOST_H_
6#define CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_PROXY_HOST_H_
7
8#include "base/memory/scoped_ptr.h"
9#include "content/browser/frame_host/render_frame_host_impl.h"
10#include "content/browser/site_instance_impl.h"
11#include "ipc/ipc_listener.h"
12#include "ipc/ipc_sender.h"
13
14class FrameTreeNode;
15class RenderProcessHost;
16class RenderFrameHostImpl;
17class RenderViewHostImpl;
18
19namespace content {
20
21// When a page's frames are rendered by multiple processes, each renderer has a
22// full copy of the frame tree. It has full RenderFrames for the frames it is
23// responsible for rendering and placeholder objects (i.e., RenderFrameProxies)
24// for frames rendered by other processes.
25//
26// This class is the browser-side host object for the placeholder. Each node in
27// the frame tree has a RenderFrameHost for the active SiteInstance and a set
28// of RenderFrameProxyHost objects - one for all other SiteInstances with
29// references to this frame. The proxies allow us to keep existing window
30// references valid over cross-process navigations and route cross-site
31// asynchronous JavaScript calls, such as postMessage.
32//
33// For now, RenderFrameProxyHost is created when a RenderFrameHost is swapped
34// out and acts just as a wrapper. It is destroyed when the RenderFrameHost is
35// swapped back in or is no longer referenced and is therefore deleted.
36//
37// Long term, RenderFrameProxyHost will be created whenever a cross-site
38// navigation occurs and a reference to the frame navigating needs to be kept
39// alive. A RenderFrameProxyHost and a RenderFrameHost for the same SiteInstance
40// can exist at the same time, but only one will be "active" at a time.
41// There are two cases where the two objects will coexist:
42// * When navigating cross-process and there is already a RenderFrameProxyHost
43// for the new SiteInstance. A pending RenderFrameHost is created, but it is
44// not used until it commits. At that point, RenderFrameHostManager transitions
45// the pending RenderFrameHost to the active one and deletes the proxy.
46// * When navigating cross-process and the existing document has an unload
47// event handler. When the new navigation commits, RenderFrameHostManager
48// creates a RenderFrameProxyHost for the old SiteInstance and uses it going
49// forward. It also instructs the RenderFrameHost to run the unload event
50// handler and is kept alive for the duration. Once the event handling is
51// complete, the RenderFrameHost is deleted.
52class RenderFrameProxyHost
53    : public IPC::Listener,
54      public IPC::Sender {
55 public:
56  RenderFrameProxyHost(SiteInstance* site_instance,
57                       FrameTreeNode* frame_tree_node);
58  virtual ~RenderFrameProxyHost();
59
60  RenderProcessHost* GetProcess() {
61    return site_instance_->GetProcess();
62  }
63
64  int GetRoutingID() {
65    return routing_id_;
66  }
67
68  SiteInstance* GetSiteInstance() {
69    return site_instance_.get();
70  }
71
72  // TODO(nasko): The following methods should be removed once we don't have a
73  // swapped out state on RenderFrameHosts. See https://crbug.com/357747.
74  RenderFrameHostImpl* render_frame_host() {
75    return render_frame_host_.get();
76  }
77  RenderViewHostImpl* GetRenderViewHost();
78
79  void TakeFrameHostOwnership(
80      scoped_ptr<RenderFrameHostImpl> render_frame_host) {
81    render_frame_host_ = render_frame_host.Pass();
82  }
83  scoped_ptr<RenderFrameHostImpl> PassFrameHostOwnership();
84
85  // IPC::Sender
86  virtual bool Send(IPC::Message* msg) OVERRIDE;
87
88 private:
89  // IPC::Listener
90  virtual bool OnMessageReceived(const IPC::Message& msg) OVERRIDE;
91
92  // This RenderFrameProxyHost's routing id.
93  int routing_id_;
94
95  // The SiteInstance this proxy is associated with.
96  scoped_refptr<SiteInstance> site_instance_;
97
98  // The node in the frame tree where this proxy is located.
99  FrameTreeNode* frame_tree_node_;
100
101  // TODO(nasko): This can be removed once we don't have a swapped out state on
102  // RenderFrameHosts. See https://crbug.com/357747.
103  scoped_ptr<RenderFrameHostImpl> render_frame_host_;
104
105  DISALLOW_COPY_AND_ASSIGN(RenderFrameProxyHost);
106};
107
108}  // namespace
109
110#endif  // CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_PROXY_HOST_H_
111