content/browser/host_zoom_map_impl.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_HOST_ZOOM_MAP_IMPL_H_
   6 #define CONTENT_BROWSER_HOST_ZOOM_MAP_IMPL_H_
   7
   8 #include <map>
   9 #include <string>
  10 #include <vector>
  11
  12 #include "base/compiler_specific.h"
  13 #include "base/sequenced_task_runner_helpers.h"
  14 #include "base/supports_user_data.h"
  15 #include "base/synchronization/lock.h"
  16 #include "content/public/browser/host_zoom_map.h"
  17 #include "content/public/browser/notification_observer.h"
  18 #include "content/public/browser/notification_registrar.h"
  19
  20 namespace content {
  21
  22 // HostZoomMap needs to be deleted on the UI thread because it listens
  23 // to notifications on there (and holds a NotificationRegistrar).
  24 class CONTENT_EXPORT HostZoomMapImpl : public NON_EXPORTED_BASE(HostZoomMap),
  25                                        public NotificationObserver,
  26                                        public base::SupportsUserData::Data {
  27  public:
  28   HostZoomMapImpl();
  29   virtual ~HostZoomMapImpl();
  30
  31   // HostZoomMap implementation:
  32   virtual void CopyFrom(HostZoomMap* copy) OVERRIDE;
  33   virtual double GetZoomLevel(const std::string& host) const OVERRIDE;
  34   virtual void SetZoomLevel(const std::string& host, double level) OVERRIDE;
  35   virtual double GetDefaultZoomLevel() const OVERRIDE;
  36   virtual void SetDefaultZoomLevel(double level) OVERRIDE;
  37
  38   // Returns the temporary zoom level that's only valid for the lifetime of
  39   // the given WebContents (i.e. isn't saved and doesn't affect other
  40   // WebContentses) if it exists, the default zoom level otherwise.
  41   //
  42   // This may be called on any thread.
  43   double GetTemporaryZoomLevel(int render_process_id,
  44                                int render_view_id) const;
  45
  46   // Sets the temporary zoom level that's only valid for the lifetime of this
  47   // WebContents.
  48   //
  49   // This should only be called on the UI thread.
  50   void SetTemporaryZoomLevel(int render_process_id,
  51                              int render_view_id,
  52                              double level);
  53
  54   // NotificationObserver implementation.
  55   virtual void Observe(int type,
  56                        const NotificationSource& source,
  57                        const NotificationDetails& details) OVERRIDE;
  58
  59  private:
  60   typedef std::map<std::string, double> HostZoomLevels;
  61
  62   // Copy of the pref data, so that we can read it on the IO thread.
  63   HostZoomLevels host_zoom_levels_;
  64   double default_zoom_level_;
  65
  66   struct TemporaryZoomLevel {
  67     int render_process_id;
  68     int render_view_id;
  69     double zoom_level;
  70   };
  71
  72   // Don't expect more than a couple of tabs that are using a temporary zoom
  73   // level, so vector is fine for now.
  74   std::vector<TemporaryZoomLevel> temporary_zoom_levels_;
  75
  76   // Used around accesses to |host_zoom_levels_|, |default_zoom_level_| and
  77   // |temporary_zoom_levels_| to guarantee thread safety.
  78   mutable base::Lock lock_;
  79
  80   NotificationRegistrar registrar_;
  81
  82   DISALLOW_COPY_AND_ASSIGN(HostZoomMapImpl);
  83 };
  84
  85 }  // namespace content
  86
  87 #endif  // CONTENT_BROWSER_HOST_ZOOM_MAP_IMPL_H_