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 CHROME_BROWSER_ICON_LOADER_H_
6#define CHROME_BROWSER_ICON_LOADER_H_
7
8#include "build/build_config.h"
9
10#include <string>
11
12#include "base/basictypes.h"
13#include "base/files/file_path.h"
14#include "base/memory/ref_counted.h"
15#include "base/memory/scoped_ptr.h"
16#include "base/message_loop/message_loop_proxy.h"
17#include "content/public/browser/browser_thread.h"
18#include "ui/gfx/image/image.h"
19
20#if defined(OS_WIN)
21// On Windows, we group files by their extension, with several exceptions:
22// .dll, .exe, .ico. See IconManager.h for explanation.
23typedef std::wstring IconGroupID;
24#elif defined(OS_POSIX)
25// On POSIX, we group files by MIME type.
26typedef std::string IconGroupID;
27#endif
28
29////////////////////////////////////////////////////////////////////////////////
30//
31// A facility to read a file containing an icon asynchronously in the IO
32// thread. Returns the icon in the form of an ImageSkia.
33//
34////////////////////////////////////////////////////////////////////////////////
35class IconLoader : public base::RefCountedThreadSafe<IconLoader> {
36 public:
37  enum IconSize {
38    SMALL = 0,  // 16x16
39    NORMAL,     // 32x32
40    LARGE,      // Windows: 32x32, Linux: 48x48, Mac: Unsupported
41    ALL,        // All sizes available
42  };
43
44  class Delegate {
45   public:
46    // Invoked when an icon group has been read, but before the icon data
47    // is read. If the icon is already cached, this method should call and
48    // return the results of OnImageLoaded with the cached image.
49    virtual bool OnGroupLoaded(IconLoader* source,
50                               const IconGroupID& group) = 0;
51    // Invoked when an icon has been read. |source| is the IconLoader. If the
52    // icon has been successfully loaded, result is non-null. This method must
53    // return true if it is taking ownership of the returned image.
54    virtual bool OnImageLoaded(IconLoader* source,
55                               gfx::Image* result,
56                               const IconGroupID& group) = 0;
57
58   protected:
59    virtual ~Delegate() {}
60  };
61
62  IconLoader(const base::FilePath& file_path,
63             IconSize size,
64             Delegate* delegate);
65
66  // Start reading the icon on the file thread.
67  void Start();
68
69 private:
70  friend class base::RefCountedThreadSafe<IconLoader>;
71
72  virtual ~IconLoader();
73
74  // Get the identifying string for the given file. The implementation
75  // is in icon_loader_[platform].cc.
76  static IconGroupID ReadGroupIDFromFilepath(const base::FilePath& path);
77
78  // Some icons (exe's on windows) can change as they're loaded.
79  static bool IsIconMutableFromFilepath(const base::FilePath& path);
80
81  // The thread ReadIcon() should be called on.
82  static content::BrowserThread::ID ReadIconThreadID();
83
84  void ReadGroup();
85  void OnReadGroup();
86  void ReadIcon();
87
88  void NotifyDelegate();
89
90  // The message loop object of the thread in which we notify the delegate.
91  scoped_refptr<base::MessageLoopProxy> target_message_loop_;
92
93  base::FilePath file_path_;
94
95  IconGroupID group_;
96
97  IconSize icon_size_;
98
99  scoped_ptr<gfx::Image> image_;
100
101  Delegate* delegate_;
102
103  DISALLOW_COPY_AND_ASSIGN(IconLoader);
104};
105
106#endif  // CHROME_BROWSER_ICON_LOADER_H_
107