1 files changed, 57 insertions, 0 deletions
diff --git a/image/IProgressObserver.h b/image/IProgressObserver.h
new file mode 100644
index 0000000000..c4b16f70de
--- /dev/null
+++ b/image/IProgressObserver.h
@@ -0,0 +1,57 @@
+/* -*- 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_image_IProgressObserver_h
+#define mozilla_image_IProgressObserver_h
+
+#include "mozilla/WeakPtr.h"
+#include "nsISupports.h"
+#include "nsRect.h"
+
+class nsIEventTarget;
+
+namespace mozilla {
+namespace image {
+
+/**
+ * An interface for observing changes to image state, as reported by
+ * ProgressTracker.
+ *
+ * This is the ImageLib-internal version of imgINotificationObserver,
+ * essentially, with implementation details that code outside of ImageLib
+ * shouldn't see.
+ *
+ * XXX(seth): It's preferable to avoid adding anything to this interface if
+ * possible.  In the long term, it would be ideal to get to a place where we can
+ * just use the imgINotificationObserver interface internally as well.
+ */
+class IProgressObserver : public SupportsWeakPtr {
+ public:
+  // Subclasses may or may not be XPCOM classes, so we just require that they
+  // implement AddRef and Release.
+  NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
+
+  // imgINotificationObserver methods:
+  virtual void Notify(int32_t aType, const nsIntRect* aRect = nullptr) = 0;
+  virtual void OnLoadComplete(bool aLastPart) = 0;
+
+  // Other, internal-only methods:
+  virtual void SetHasImage() = 0;
+  virtual bool NotificationsDeferred() const = 0;
+  virtual void MarkPendingNotify() = 0;
+  virtual void ClearPendingNotify() = 0;
+
+  virtual already_AddRefed<nsIEventTarget> GetEventTarget() const {
+    return nullptr;
+  }
+
+ protected:
+  virtual ~IProgressObserver() = default;
+};
+
+}  // namespace image
+}  // namespace mozilla
+
+#endif  // mozilla_image_IProgressObserver_h