content/browser/frame_host/render_frame_proxy_host.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 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
  14 class FrameTreeNode;
  15 class RenderProcessHost;
  16 class RenderFrameHostImpl;
  17 class RenderViewHostImpl;
  18
  19 namespace 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.
  52 class 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_