1 files changed, 70 insertions, 0 deletions
diff --git a/widget/windows/IconLoaderHelperWin.h b/widget/windows/IconLoaderHelperWin.h
new file mode 100644
index 0000000000..94eba152e4
--- /dev/null
+++ b/widget/windows/IconLoaderHelperWin.h
@@ -0,0 +1,70 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_IconLoaderHelperWin_h
+#define mozilla_widget_IconLoaderHelperWin_h
+
+#include "mozilla/widget/IconLoader.h"
+#include "nsISupports.h"
+
+namespace mozilla::widget {
+
+/**
+ * Classes that want to hear about when icons load should subclass
+ * IconLoaderListenerWin, and implement the OnComplete() method,
+ * which will be called once the load of the icon has completed.
+ */
+class IconLoaderListenerWin : public nsISupports {
+ public:
+  IconLoaderListenerWin() = default;
+
+  // IconLoaderListenerWin needs to implement nsISupports in order for its
+  // subclasses to participate in cycle collection.
+
+  virtual nsresult OnComplete() = 0;
+
+ protected:
+  virtual ~IconLoaderListenerWin() = default;
+};
+
+/**
+ * This is a Helper used with mozilla::widget::IconLoader that implements the
+ * Windows-specific functionality for converting a loaded icon into an HICON.
+ */
+class IconLoaderHelperWin final : public mozilla::widget::IconLoader::Helper {
+ public:
+  explicit IconLoaderHelperWin(
+      mozilla::widget::IconLoaderListenerWin* aLoadListener);
+
+  // IconLoaderHelperWin needs to implement nsISupports in order for its
+  // subclasses to participate in cycle collection.
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_CLASS(IconLoaderHelperWin)
+
+  nsresult OnComplete(imgIContainer* aImage, const nsIntRect& aRect) override;
+
+  /**
+   * IconLoaderHelperWin will default the HICON returned by GetNativeIconImage
+   * to the application icon. Once the load of the icon by IconLoader has
+   * completed, GetNativeIconImage will return the loaded icon.
+   *
+   * Note that IconLoaderHelperWin owns this HICON. If you don't need it to hold
+   * onto the HICON anymore, call Destroy on it to deallocate. The
+   * IconLoaderHelperWin destructor will also deallocate the HICON if necessary.
+   */
+  HICON GetNativeIconImage();
+  void Destroy();
+
+ protected:
+  ~IconLoaderHelperWin();
+
+ private:
+  RefPtr<mozilla::widget::IconLoaderListenerWin> mLoadListener;
+  HICON mNativeIconImage;
+};
+
+}  // namespace mozilla::widget
+
+#endif  // mozilla_widget_IconLoaderHelperWin_h