1// Copyright (c) 2011 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#pragma once
8
9#include "build/build_config.h"
10
11#include <string>
12
13#include "base/basictypes.h"
14#include "base/memory/ref_counted.h"
15#include "base/memory/scoped_ptr.h"
16#include "base/message_loop_proxy.h"
17#include "ui/gfx/image.h"
18
19#if defined(TOOLKIT_USES_GTK)
20#include "base/file_path.h"
21#endif
22
23#if defined(OS_WIN)
24// On Windows, we group files by their extension, with several exceptions:
25// .dll, .exe, .ico. See IconManager.h for explanation.
26typedef std::wstring IconGroupID;
27#elif defined(OS_POSIX)
28// On POSIX, we group files by MIME type.
29typedef std::string IconGroupID;
30#endif
31
32////////////////////////////////////////////////////////////////////////////////
33//
34// A facility to read a file containing an icon asynchronously in the IO
35// thread. Returns the icon in the form of an SkBitmap.
36//
37////////////////////////////////////////////////////////////////////////////////
38class IconLoader : public base::RefCountedThreadSafe<IconLoader> {
39 public:
40  enum IconSize {
41    SMALL = 0,  // 16x16
42    NORMAL,     // 32x32
43    LARGE
44  };
45
46  class Delegate {
47   public:
48    // Invoked when an icon has been read. |source| is the IconLoader. If the
49    // icon has been successfully loaded, result is non-null. This method must
50    // return true if it is taking ownership of the returned bitmap.
51    virtual bool OnImageLoaded(IconLoader* source, gfx::Image* result) = 0;
52
53   protected:
54    virtual ~Delegate() {}
55  };
56
57  IconLoader(const IconGroupID& group, IconSize size, Delegate* delegate);
58
59  // Start reading the icon on the file thread.
60  void Start();
61
62 private:
63  friend class base::RefCountedThreadSafe<IconLoader>;
64
65  virtual ~IconLoader();
66
67  void ReadIcon();
68
69  void NotifyDelegate();
70
71  // The message loop object of the thread in which we notify the delegate.
72  scoped_refptr<base::MessageLoopProxy> target_message_loop_;
73
74  IconGroupID group_;
75
76  IconSize icon_size_;
77
78  scoped_ptr<gfx::Image> image_;
79
80  Delegate* delegate_;
81
82#if defined(TOOLKIT_USES_GTK)
83  // On X11 we use gdk's pixbuf loader, which has to execute on the UI
84  // thread, so we only read the file on the background thread and parse it
85  // on the main thread.
86  void ParseIcon();
87  FilePath filename_;
88  std::string icon_data_;
89#endif
90
91  DISALLOW_COPY_AND_ASSIGN(IconLoader);
92};
93
94#endif  // CHROME_BROWSER_ICON_LOADER_H_
95