content/browser/renderer_host/render_widget_helper.h

   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.
   4
   5 #ifndef CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HELPER_H_
   6 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HELPER_H_
   7
   8 #include <map>
   9
  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"
  21
  22 namespace IPC {
  23 class Message;
  24 }
  25
  26 namespace base {
  27 class TimeDelta;
  28 }
  29
  30 struct GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params;
  31 struct ViewHostMsg_CreateWindow_Params;
  32 struct ViewMsg_SwapOut_Params;
  33
  34 namespace content {
  35 class GpuProcessHost;
  36 class ResourceDispatcherHostImpl;
  37 class SessionStorageNamespace;
  38
  39 // Instantiated per RenderProcessHost to provide various optimizations on
  40 // behalf of a RenderWidgetHost.  This class bridges between the IO thread
  41 // where the RenderProcessHost's MessageFilter lives and the UI thread where
  42 // the RenderWidgetHost lives.
  43 //
  44 //
  45 // OPTIMIZED TAB SWITCHING
  46 //
  47 //   When a RenderWidgetHost is in a background tab, it is flagged as hidden.
  48 //   This causes the corresponding RenderWidget to stop sending BackingStore
  49 //   messages. The RenderWidgetHost also discards its backingstore when it is
  50 //   hidden, which helps free up memory.  As a result, when a RenderWidgetHost
  51 //   is restored, it can be momentarily be without a backingstore.  (Restoring
  52 //   a RenderWidgetHost results in a WasShown message being sent to the
  53 //   RenderWidget, which triggers a full BackingStore message.)  This can lead
  54 //   to an observed rendering glitch as the WebContentsImpl will just have to
  55 //   fill white overtop the RenderWidgetHost until the RenderWidgetHost
  56 //   receives a BackingStore message to refresh its backingstore.
  57 //
  58 //   To avoid this 'white flash', the RenderWidgetHost again makes use of the
  59 //   RenderWidgetHelper's WaitForBackingStoreMsg method.  When the
  60 //   RenderWidgetHost's GetBackingStore method is called, it will call
  61 //   WaitForBackingStoreMsg if it has no backingstore.
  62 //
  63 // TRANSPORT DIB CREATION
  64 //
  65 //   On some platforms (currently the Mac) the renderer cannot create transport
  66 //   DIBs because of sandbox limitations. Thus, it has to make synchronous IPCs
  67 //   to the browser for them. Since these requests are synchronous, they cannot
  68 //   terminate on the UI thread. Thus, in this case, this object performs the
  69 //   allocation and maintains the set of allocated transport DIBs which the
  70 //   renderers can refer to.
  71 //
  72
  73 class RenderWidgetHelper
  74     : public base::RefCountedThreadSafe<RenderWidgetHelper,
  75                                         BrowserThread::DeleteOnIOThread> {
  76  public:
  77   RenderWidgetHelper();
  78
  79   void Init(int render_process_id,
  80             ResourceDispatcherHostImpl* resource_dispatcher_host);
  81
  82   // Gets the next available routing id.  This is thread safe.
  83   int GetNextRoutingID();
  84
  85   // IO THREAD ONLY -----------------------------------------------------------
  86
  87   // Lookup the RenderWidgetHelper from the render_process_host_id. Returns NULL
  88   // if not found. NOTE: The raw pointer is for temporary use only. To retain,
  89   // store in a scoped_refptr.
  90   static RenderWidgetHelper* FromProcessHostID(int render_process_host_id);
  91
  92   // UI THREAD ONLY -----------------------------------------------------------
  93
  94   // These four functions provide the backend implementation of the
  95   // corresponding functions in RenderProcessHost. See those declarations
  96   // for documentation.
  97   void ResumeDeferredNavigation(const GlobalRequestID& request_id);
  98   void ResumeResponseDeferredAtStart(const GlobalRequestID& request_id);
  99
 100   // Called to resume the requests for a view after it's ready. The view was
 101   // created by CreateNewWindow which initially blocked the requests.
 102   void ResumeRequestsForView(int route_id);
 103
 104   // IO THREAD ONLY -----------------------------------------------------------
 105
 106   void CreateNewWindow(
 107       const ViewHostMsg_CreateWindow_Params& params,
 108       bool no_javascript_access,
 109       base::ProcessHandle render_process,
 110       int* route_id,
 111       int* main_frame_route_id,
 112       int* surface_id,
 113       SessionStorageNamespace* session_storage_namespace);
 114   void CreateNewWidget(int opener_id,
 115                        blink::WebPopupType popup_type,
 116                        int* route_id,
 117                        int* surface_id);
 118   void CreateNewFullscreenWidget(int opener_id, int* route_id, int* surface_id);
 119
 120 #if defined(OS_POSIX)
 121   // Called on the IO thread to handle the allocation of a TransportDIB.  If
 122   // |cache_in_browser| is |true|, then a copy of the shmem is kept by the
 123   // browser, and it is the caller's repsonsibility to call
 124   // FreeTransportDIB().  In all cases, the caller is responsible for deleting
 125   // the resulting TransportDIB.
 126   void AllocTransportDIB(uint32 size,
 127                          bool cache_in_browser,
 128                          TransportDIB::Handle* result);
 129
 130   // Called on the IO thread to handle the freeing of a transport DIB
 131   void FreeTransportDIB(TransportDIB::Id dib_id);
 132 #endif
 133
 134  private:
 135   friend class base::RefCountedThreadSafe<RenderWidgetHelper>;
 136   friend struct BrowserThread::DeleteOnThread<BrowserThread::IO>;
 137   friend class base::DeleteHelper<RenderWidgetHelper>;
 138
 139   ~RenderWidgetHelper();
 140
 141   // Called on the UI thread to finish creating a window.
 142   void OnCreateWindowOnUI(
 143       const ViewHostMsg_CreateWindow_Params& params,
 144       int route_id,
 145       int main_frame_route_id,
 146       SessionStorageNamespace* session_storage_namespace);
 147
 148   // Called on the IO thread after a window was created on the UI thread.
 149   void OnResumeRequestsForView(int route_id);
 150
 151   // Called on the UI thread to finish creating a widget.
 152   void OnCreateWidgetOnUI(int opener_id,
 153                           int route_id,
 154                           blink::WebPopupType popup_type);
 155
 156   // Called on the UI thread to create a fullscreen widget.
 157   void OnCreateFullscreenWidgetOnUI(int opener_id, int route_id);
 158
 159   // Called on the IO thread to resume a paused navigation in the network
 160   // stack without transferring it to a new renderer process.
 161   void OnResumeDeferredNavigation(const GlobalRequestID& request_id);
 162
 163   // Called on the IO thread to resume a navigation paused immediately after
 164   // receiving response headers.
 165   void OnResumeResponseDeferredAtStart(const GlobalRequestID& request_id);
 166
 167 #if defined(OS_POSIX)
 168   // Called on destruction to release all allocated transport DIBs
 169   void ClearAllocatedDIBs();
 170
 171   // On POSIX we keep file descriptors to all the allocated DIBs around until
 172   // the renderer frees them.
 173   base::Lock allocated_dibs_lock_;
 174   std::map<TransportDIB::Id, int> allocated_dibs_;
 175 #endif
 176
 177   int render_process_id_;
 178
 179   // The next routing id to use.
 180   base::AtomicSequenceNumber next_routing_id_;
 181
 182   ResourceDispatcherHostImpl* resource_dispatcher_host_;
 183
 184   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHelper);
 185 };
 186
 187 }  // namespace content
 188
 189 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HELPER_H_