content/public/browser/host_zoom_map.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_PUBLIC_BROWSER_HOST_ZOOM_MAP_H_
   6 #define CONTENT_PUBLIC_BROWSER_HOST_ZOOM_MAP_H_
   7
   8 #include <map>
   9 #include <string>
  10 #include <vector>
  11
  12 #include "base/basictypes.h"
  13 #include "base/callback.h"
  14 #include "base/callback_list.h"
  15 #include "content/common/content_export.h"
  16
  17 namespace content {
  18
  19 class BrowserContext;
  20 class ResourceContext;
  21
  22 // Maps hostnames to custom zoom levels.  Written on the UI thread and read on
  23 // any thread.  One instance per browser context. Must be created on the UI
  24 // thread, and it'll delete itself on the UI thread as well.
  25 // Zoom can be defined at three levels: default zoom, zoom for host, and zoom
  26 // for host with specific scheme. Setting any of the levels leaves settings
  27 // for other settings intact. Getting the zoom level starts at the most
  28 // specific setting and progresses to the less specific: first the zoom for the
  29 // host and scheme pair is checked, secondly the zoom for the host only and
  30 // lastly default zoom.
  31
  32 class HostZoomMap {
  33  public:
  34   // Enum that indicates what was the scope of zoom level change.
  35   enum ZoomLevelChangeMode {
  36     ZOOM_CHANGED_FOR_HOST,            // Zoom level changed for host.
  37     ZOOM_CHANGED_FOR_SCHEME_AND_HOST, // Zoom level changed for scheme/host
  38                                       // pair.
  39     ZOOM_CHANGED_TEMPORARY_ZOOM,      // Temporary zoom change for specific
  40                                       // renderer, no scheme/host is specified.
  41   };
  42
  43   // Structure used to notify about zoom changes. Host and/or scheme are empty
  44   // if not applicable to |mode|.
  45   struct ZoomLevelChange {
  46     ZoomLevelChangeMode mode;
  47     std::string host;
  48     std::string scheme;
  49     double zoom_level;
  50   };
  51
  52   CONTENT_EXPORT static HostZoomMap* GetForBrowserContext(
  53       BrowserContext* browser_context);
  54
  55   // Copy the zoom levels from the given map. Can only be called on the UI
  56   // thread.
  57   virtual void CopyFrom(HostZoomMap* copy) = 0;
  58
  59   // Here |host| is the host portion of URL, or (in the absence of a host)
  60   // the complete spec of the URL.
  61   // Returns the zoom for the specified |scheme| and |host|. See class
  62   // description for details.
  63   //
  64   // This may be called on any thread.
  65   virtual double GetZoomLevelForHostAndScheme(
  66       const std::string& scheme,
  67       const std::string& host) const = 0;
  68
  69   // Here |host| is the host portion of URL, or (in the absence of a host)
  70   // the complete spec of the URL.
  71   // Sets the zoom level for the |host| to |level|.  If the level matches the
  72   // current default zoom level, the host is erased from the saved preferences;
  73   // otherwise the new value is written out.
  74   // Zoom levels specified for both scheme and host are not affected.
  75   //
  76   // This should only be called on the UI thread.
  77   virtual void SetZoomLevelForHost(const std::string& host, double level) = 0;
  78
  79   // Here |host| is the host portion of URL, or (in the absence of a host)
  80   // the complete spec of the URL.
  81   // Sets the zoom level for the |scheme|/|host| pair to |level|. No values
  82   // will be erased during this operation, and this value will not be stored in
  83   // the preferences.
  84   //
  85   // This should only be called on the UI thread.
  86   virtual void SetZoomLevelForHostAndScheme(const std::string& scheme,
  87                                             const std::string& host,
  88                                             double level) = 0;
  89
  90   // Get/Set the default zoom level for pages that don't override it.
  91   virtual double GetDefaultZoomLevel() const = 0;
  92   virtual void SetDefaultZoomLevel(double level) = 0;;
  93
  94   typedef base::Callback<void(const ZoomLevelChange&)> ZoomLevelChangedCallback;
  95   typedef base::CallbackList<void(const ZoomLevelChange&)>::Subscription
  96       Subscription;
  97   // Add and remove zoom level changed callbacks.
  98   virtual scoped_ptr<Subscription> AddZoomLevelChangedCallback(
  99       const ZoomLevelChangedCallback& callback) = 0;
 100
 101  protected:
 102   virtual ~HostZoomMap() {}
 103 };
 104
 105 }  // namespace content
 106
 107 #endif  // CONTENT_PUBLIC_BROWSER_HOST_ZOOM_MAP_H_