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      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 UI_WM_CORE_CAPTURE_CONTROLLER_H_
      6 #define UI_WM_CORE_CAPTURE_CONTROLLER_H_
      7 
      8 #include <set>
      9 
     10 #include "base/basictypes.h"
     11 #include "base/compiler_specific.h"
     12 #include "ui/aura/client/capture_client.h"
     13 #include "ui/aura/window_observer.h"
     14 #include "ui/wm/wm_export.h"
     15 
     16 namespace wm {
     17 
     18 // Internal CaptureClient implementation. See ScopedCaptureClient for details.
     19 class WM_EXPORT CaptureController : public aura::client::CaptureClient {
     20  public:
     21   // Adds |root| to the list of RootWindows notified when capture changes.
     22   void Attach(aura::Window* root);
     23 
     24   // Removes |root| from the list of RootWindows notified when capture changes.
     25   void Detach(aura::Window* root);
     26 
     27   // Returns true if this CaptureController is installed on at least one
     28   // RootWindow.
     29   bool is_active() const { return !root_windows_.empty(); }
     30 
     31   // Overridden from aura::client::CaptureClient:
     32   virtual void SetCapture(aura::Window* window) OVERRIDE;
     33   virtual void ReleaseCapture(aura::Window* window) OVERRIDE;
     34   virtual aura::Window* GetCaptureWindow() OVERRIDE;
     35   virtual aura::Window* GetGlobalCaptureWindow() OVERRIDE;
     36 
     37  private:
     38   friend class ScopedCaptureClient;
     39   typedef std::set<aura::Window*> RootWindows;
     40 
     41   CaptureController();
     42   virtual ~CaptureController();
     43 
     44   // The current capture window. NULL if there is no capture window.
     45   aura::Window* capture_window_;
     46 
     47   // Set of RootWindows notified when capture changes.
     48   RootWindows root_windows_;
     49 
     50   DISALLOW_COPY_AND_ASSIGN(CaptureController);
     51 };
     52 
     53 // ScopedCaptureClient is responsible for creating a CaptureClient for a
     54 // RootWindow. Specifically it creates a single CaptureController that is shared
     55 // among all ScopedCaptureClients and adds the RootWindow to it.
     56 class WM_EXPORT ScopedCaptureClient : public aura::WindowObserver {
     57  public:
     58   explicit ScopedCaptureClient(aura::Window* root);
     59   virtual ~ScopedCaptureClient();
     60 
     61   // Returns true if there is a CaptureController with at least one RootWindow.
     62   static bool IsActive();
     63 
     64   aura::client::CaptureClient* capture_client() {
     65     return capture_controller_;
     66   }
     67 
     68   // Overridden from aura::WindowObserver:
     69   virtual void OnWindowDestroyed(aura::Window* window) OVERRIDE;
     70 
     71  private:
     72   // Invoked from destructor and OnWindowDestroyed() to cleanup.
     73   void Shutdown();
     74 
     75   // The single CaptureController instance.
     76   static CaptureController* capture_controller_;
     77 
     78   // RootWindow this ScopedCaptureClient was create for.
     79   aura::Window* root_window_;
     80 
     81   DISALLOW_COPY_AND_ASSIGN(ScopedCaptureClient);
     82 };
     83 
     84 }  // namespace wm
     85 
     86 #endif  // UI_WM_CORE_CAPTURE_CONTROLLER_H_
     87