widget/windows/IconLoaderHelperWin.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef mozilla_widget_IconLoaderHelperWin_h
   7 #define mozilla_widget_IconLoaderHelperWin_h
   8
   9 #include "mozilla/widget/IconLoader.h"
  10 #include "nsISupports.h"
  11
  12 namespace mozilla::widget {
  13
  14 /**
  15  * Classes that want to hear about when icons load should subclass
  16  * IconLoaderListenerWin, and implement the OnComplete() method,
  17  * which will be called once the load of the icon has completed.
  18  */
  19 class IconLoaderListenerWin : public nsISupports {
  20  public:
  21   IconLoaderListenerWin() = default;
  22
  23   // IconLoaderListenerWin needs to implement nsISupports in order for its
  24   // subclasses to participate in cycle collection.
  25
  26   virtual nsresult OnComplete() = 0;
  27
  28  protected:
  29   virtual ~IconLoaderListenerWin() = default;
  30 };
  31
  32 /**
  33  * This is a Helper used with mozilla::widget::IconLoader that implements the
  34  * Windows-specific functionality for converting a loaded icon into an HICON.
  35  */
  36 class IconLoaderHelperWin final : public mozilla::widget::IconLoader::Helper {
  37  public:
  38   explicit IconLoaderHelperWin(
  39       mozilla::widget::IconLoaderListenerWin* aLoadListener);
  40
  41   // IconLoaderHelperWin needs to implement nsISupports in order for its
  42   // subclasses to participate in cycle collection.
  43   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  44   NS_DECL_CYCLE_COLLECTION_CLASS(IconLoaderHelperWin)
  45
  46   nsresult OnComplete(imgIContainer* aImage, const nsIntRect& aRect) override;
  47
  48   /**
  49    * IconLoaderHelperWin will default the HICON returned by GetNativeIconImage
  50    * to the application icon. Once the load of the icon by IconLoader has
  51    * completed, GetNativeIconImage will return the loaded icon.
  52    *
  53    * Note that IconLoaderHelperWin owns this HICON. If you don't need it to hold
  54    * onto the HICON anymore, call Destroy on it to deallocate. The
  55    * IconLoaderHelperWin destructor will also deallocate the HICON if necessary.
  56    */
  57   HICON GetNativeIconImage();
  58   void Destroy();
  59
  60  protected:
  61   ~IconLoaderHelperWin();
  62
  63  private:
  64   RefPtr<mozilla::widget::IconLoaderListenerWin> mLoadListener;
  65   HICON mNativeIconImage;
  66 };
  67
  68 }  // namespace mozilla::widget
  69
  70 #endif  // mozilla_widget_IconLoaderHelperWin_h