1 // Copyright (c) 2012 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.
5 #ifndef CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HELPER_H_
6 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HELPER_H_
10 #include "base/atomic_sequence_num.h"
11 #include "base/containers/hash_tables.h"
12 #include "base/memory/ref_counted.h"
13 #include "base/process/process.h"
14 #include "content/public/browser/browser_thread.h"
15 #include "content/public/browser/content_browser_client.h"
16 #include "content/public/browser/global_request_id.h"
17 #include "content/public/common/window_container_type.h"
18 #include "third_party/WebKit/public/web/WebPopupType.h"
19 #include "ui/gfx/native_widget_types.h"
20 #include "ui/surface/transport_dib.h"
30 struct ViewHostMsg_CreateWindow_Params;
31 struct ViewMsg_SwapOut_Params;
35 class ResourceDispatcherHostImpl;
36 class SessionStorageNamespace;
38 // Instantiated per RenderProcessHost to provide various optimizations on
39 // behalf of a RenderWidgetHost. This class bridges between the IO thread
40 // where the RenderProcessHost's MessageFilter lives and the UI thread where
41 // the RenderWidgetHost lives.
44 // OPTIMIZED TAB SWITCHING
46 // When a RenderWidgetHost is in a background tab, it is flagged as hidden.
47 // This causes the corresponding RenderWidget to stop sending BackingStore
48 // messages. The RenderWidgetHost also discards its backingstore when it is
49 // hidden, which helps free up memory. As a result, when a RenderWidgetHost
50 // is restored, it can be momentarily be without a backingstore. (Restoring
51 // a RenderWidgetHost results in a WasShown message being sent to the
52 // RenderWidget, which triggers a full BackingStore message.) This can lead
53 // to an observed rendering glitch as the WebContentsImpl will just have to
54 // fill white overtop the RenderWidgetHost until the RenderWidgetHost
55 // receives a BackingStore message to refresh its backingstore.
57 // To avoid this 'white flash', the RenderWidgetHost again makes use of the
58 // RenderWidgetHelper's WaitForBackingStoreMsg method. When the
59 // RenderWidgetHost's GetBackingStore method is called, it will call
60 // WaitForBackingStoreMsg if it has no backingstore.
62 // TRANSPORT DIB CREATION
64 // On some platforms (currently the Mac) the renderer cannot create transport
65 // DIBs because of sandbox limitations. Thus, it has to make synchronous IPCs
66 // to the browser for them. Since these requests are synchronous, they cannot
67 // terminate on the UI thread. Thus, in this case, this object performs the
68 // allocation and maintains the set of allocated transport DIBs which the
69 // renderers can refer to.
72 class RenderWidgetHelper
73 : public base::RefCountedThreadSafe<RenderWidgetHelper,
74 BrowserThread::DeleteOnIOThread> {
78 void Init(int render_process_id,
79 ResourceDispatcherHostImpl* resource_dispatcher_host);
81 // Gets the next available routing id. This is thread safe.
82 int GetNextRoutingID();
84 // IO THREAD ONLY -----------------------------------------------------------
86 // Lookup the RenderWidgetHelper from the render_process_host_id. Returns NULL
87 // if not found. NOTE: The raw pointer is for temporary use only. To retain,
88 // store in a scoped_refptr.
89 static RenderWidgetHelper* FromProcessHostID(int render_process_host_id);
91 // UI THREAD ONLY -----------------------------------------------------------
93 // These four functions provide the backend implementation of the
94 // corresponding functions in RenderProcessHost. See those declarations
96 void ResumeDeferredNavigation(const GlobalRequestID& request_id);
97 void ResumeResponseDeferredAtStart(const GlobalRequestID& request_id);
99 // Called to resume the requests for a view after it's ready. The view was
100 // created by CreateNewWindow which initially blocked the requests.
101 void ResumeRequestsForView(int route_id);
103 // IO THREAD ONLY -----------------------------------------------------------
105 void CreateNewWindow(
106 const ViewHostMsg_CreateWindow_Params& params,
107 bool no_javascript_access,
108 base::ProcessHandle render_process,
110 int* main_frame_route_id,
112 SessionStorageNamespace* session_storage_namespace);
113 void CreateNewWidget(int opener_id,
114 blink::WebPopupType popup_type,
117 void CreateNewFullscreenWidget(int opener_id, int* route_id, int* surface_id);
119 #if defined(OS_POSIX)
120 // Called on the IO thread to handle the allocation of a TransportDIB. If
121 // |cache_in_browser| is |true|, then a copy of the shmem is kept by the
122 // browser, and it is the caller's repsonsibility to call
123 // FreeTransportDIB(). In all cases, the caller is responsible for deleting
124 // the resulting TransportDIB.
125 void AllocTransportDIB(uint32 size,
126 bool cache_in_browser,
127 TransportDIB::Handle* result);
129 // Called on the IO thread to handle the freeing of a transport DIB
130 void FreeTransportDIB(TransportDIB::Id dib_id);
134 friend class base::RefCountedThreadSafe<RenderWidgetHelper>;
135 friend struct BrowserThread::DeleteOnThread<BrowserThread::IO>;
136 friend class base::DeleteHelper<RenderWidgetHelper>;
138 ~RenderWidgetHelper();
140 // Called on the UI thread to finish creating a window.
141 void OnCreateWindowOnUI(
142 const ViewHostMsg_CreateWindow_Params& params,
144 int main_frame_route_id,
145 SessionStorageNamespace* session_storage_namespace);
147 // Called on the IO thread after a window was created on the UI thread.
148 void OnResumeRequestsForView(int route_id);
150 // Called on the UI thread to finish creating a widget.
151 void OnCreateWidgetOnUI(int opener_id,
153 blink::WebPopupType popup_type);
155 // Called on the UI thread to create a fullscreen widget.
156 void OnCreateFullscreenWidgetOnUI(int opener_id, int route_id);
158 // Called on the IO thread to resume a paused navigation in the network
159 // stack without transferring it to a new renderer process.
160 void OnResumeDeferredNavigation(const GlobalRequestID& request_id);
162 // Called on the IO thread to resume a navigation paused immediately after
163 // receiving response headers.
164 void OnResumeResponseDeferredAtStart(const GlobalRequestID& request_id);
166 #if defined(OS_POSIX)
167 // Called on destruction to release all allocated transport DIBs
168 void ClearAllocatedDIBs();
170 // On POSIX we keep file descriptors to all the allocated DIBs around until
171 // the renderer frees them.
172 base::Lock allocated_dibs_lock_;
173 std::map<TransportDIB::Id, int> allocated_dibs_;
176 int render_process_id_;
178 // The next routing id to use.
179 base::AtomicSequenceNumber next_routing_id_;
181 ResourceDispatcherHostImpl* resource_dispatcher_host_;
183 DISALLOW_COPY_AND_ASSIGN(RenderWidgetHelper);
186 } // namespace content
188 #endif // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HELPER_H_