host_zoom_map.h revision cedac228d2dd51db4b79ea1e72c7f249408ee061 
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
17namespace content {
18
19class BrowserContext;
20class ResourceContext;
21class WebContents;
22
23// Maps hostnames to custom zoom levels.  Written on the UI thread and read on
24// any thread.  One instance per browser context. Must be created on the UI
25// thread, and it'll delete itself on the UI thread as well.
26// Zoom can be defined at three levels: default zoom, zoom for host, and zoom
27// for host with specific scheme. Setting any of the levels leaves settings
28// for other settings intact. Getting the zoom level starts at the most
29// specific setting and progresses to the less specific: first the zoom for the
30// host and scheme pair is checked, secondly the zoom for the host only and
31// lastly default zoom.
32
33class HostZoomMap {
34 public:
35  // Enum that indicates what was the scope of zoom level change.
36  enum ZoomLevelChangeMode {
37    ZOOM_CHANGED_FOR_HOST,            // Zoom level changed for host.
38    ZOOM_CHANGED_FOR_SCHEME_AND_HOST, // Zoom level changed for scheme/host
39                                      // pair.
40    ZOOM_CHANGED_TEMPORARY_ZOOM,      // Temporary zoom change for specific
41                                      // renderer, no scheme/host is specified.
42  };
43
44  // Structure used to notify about zoom changes. Host and/or scheme are empty
45  // if not applicable to |mode|.
46  struct ZoomLevelChange {
47    ZoomLevelChangeMode mode;
48    std::string host;
49    std::string scheme;
50    double zoom_level;
51  };
52
53  typedef std::vector<ZoomLevelChange> ZoomLevelVector;
54
55  CONTENT_EXPORT static HostZoomMap* GetForBrowserContext(
56      BrowserContext* browser_context);
57
58  // Returns the current zoom level for the specified WebContents. May be
59  // temporary or host-specific.
60  CONTENT_EXPORT static double GetZoomLevel(const WebContents* web_contents);
61
62  // Sets the current zoom level for the specified WebContents. The level may
63  // be temporary or host-specific depending on the particular WebContents.
64  CONTENT_EXPORT static void SetZoomLevel(const WebContents* web_contents,
65                                          double level);
66
67  // Copy the zoom levels from the given map. Can only be called on the UI
68  // thread.
69  virtual void CopyFrom(HostZoomMap* copy) = 0;
70
71  // Here |host| is the host portion of URL, or (in the absence of a host)
72  // the complete spec of the URL.
73  // Returns the zoom for the specified |scheme| and |host|. See class
74  // description for details.
75  //
76  // This may be called on any thread.
77  virtual double GetZoomLevelForHostAndScheme(
78      const std::string& scheme,
79      const std::string& host) const = 0;
80
81  // Returns all non-temporary zoom levels. Can only be called on any thread.
82  virtual ZoomLevelVector GetAllZoomLevels() const = 0;
83
84  // Here |host| is the host portion of URL, or (in the absence of a host)
85  // the complete spec of the URL.
86  // Sets the zoom level for the |host| to |level|.  If the level matches the
87  // current default zoom level, the host is erased from the saved preferences;
88  // otherwise the new value is written out.
89  // Zoom levels specified for both scheme and host are not affected.
90  //
91  // This should only be called on the UI thread.
92  virtual void SetZoomLevelForHost(const std::string& host, double level) = 0;
93
94  // Here |host| is the host portion of URL, or (in the absence of a host)
95  // the complete spec of the URL.
96  // Sets the zoom level for the |scheme|/|host| pair to |level|. No values
97  // will be erased during this operation, and this value will not be stored in
98  // the preferences.
99  //
100  // This should only be called on the UI thread.
101  virtual void SetZoomLevelForHostAndScheme(const std::string& scheme,
102                                            const std::string& host,
103                                            double level) = 0;
104
105  // Get/Set the default zoom level for pages that don't override it.
106  virtual double GetDefaultZoomLevel() const = 0;
107  virtual void SetDefaultZoomLevel(double level) = 0;;
108
109  typedef base::Callback<void(const ZoomLevelChange&)> ZoomLevelChangedCallback;
110  typedef base::CallbackList<void(const ZoomLevelChange&)>::Subscription
111      Subscription;
112  // Add and remove zoom level changed callbacks.
113  virtual scoped_ptr<Subscription> AddZoomLevelChangedCallback(
114      const ZoomLevelChangedCallback& callback) = 0;
115
116 protected:
117  virtual ~HostZoomMap() {}
118};
119
120}  // namespace content
121
122#endif  // CONTENT_PUBLIC_BROWSER_HOST_ZOOM_MAP_H_
123