host_zoom_map.h revision 4e180b6a0b4720a9b8e9e959a882386f690f08ff 
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;
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
32class 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_
108