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