Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 120 insertions, 0 deletions

diff --git a/layout/generic/ScrollbarActivity.h b/layout/generic/ScrollbarActivity.h
new file mode 100644
index 0000000000..c92665b4a2
--- /dev/null
+++ b/layout/generic/ScrollbarActivity.h
@@ -0,0 +1,120 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 ScrollbarActivity_h___
+#define ScrollbarActivity_h___
+
+#include "mozilla/Assertions.h"
+#include "nsCOMPtr.h"
+#include "nsIDOMEventListener.h"
+
+class nsIContent;
+class nsIScrollbarMediator;
+class nsITimer;
+
+namespace mozilla {
+
+namespace dom {
+class Element;
+class EventTarget;
+}  // namespace dom
+
+namespace layout {
+
+/**
+ * ScrollbarActivity
+ *
+ * This class manages scrollbar behavior that imitates the native Mac OS X
+ * Lion overlay scrollbar behavior: Scrollbars are only shown while "scrollbar
+ * activity" occurs, and they're hidden with a fade animation after a short
+ * delay.
+ *
+ * Scrollbar activity has these states:
+ *  - inactive:
+ *      Scrollbars are hidden.
+ *  - ongoing activity:
+ *      Scrollbars are visible and being operated on in some way, for example
+ *      because they're hovered or pressed.
+ *  - active, but waiting for fade out
+ *      Scrollbars are still completely visible but are about to fade away.
+ *  - fading out
+ *      Scrollbars are subject to a fade-out animation.
+ *
+ * Initial scrollbar activity needs to be reported by the scrollbar holder that
+ * owns the ScrollbarActivity instance. This needs to happen via a call to
+ * ActivityOccurred(), for example when the current scroll position or the size
+ * of the scroll area changes.
+ *
+ * As soon as scrollbars are visible, the ScrollbarActivity class manages the
+ * rest of the activity behavior: It ensures that mouse motions inside the
+ * scroll area keep the scrollbars visible, and that scrollbars don't fade away
+ * while they're being hovered / dragged. It also sets a sticky hover attribute
+ * on the most recently hovered scrollbar.
+ *
+ * ScrollbarActivity falls into hibernation after the scrollbars have faded
+ * out. It only starts acting after the next call to ActivityOccurred() /
+ * ActivityStarted().
+ */
+
+class ScrollbarActivity final : public nsIDOMEventListener {
+ public:
+  explicit ScrollbarActivity(nsIScrollbarMediator* aScrollableFrame)
+      : mScrollableFrame(aScrollableFrame) {
+    MOZ_ASSERT(mScrollableFrame);
+  }
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIDOMEVENTLISTENER
+
+  void Destroy();
+
+  void ActivityOccurred();
+  void ActivityStarted();
+  void ActivityStopped();
+
+  bool IsActive() const { return mNestedActivityCounter; }
+
+ protected:
+  virtual ~ScrollbarActivity() = default;
+
+  void StartFadeTimer();
+  void CancelFadeTimer();
+  void BeginFade();
+  void HandleEventForScrollbar(const nsAString& aType, nsIContent* aTarget,
+                               dom::Element* aScrollbar,
+                               bool* aStoredHoverState);
+
+  void StartListeningForScrollbarEvents();
+  void StartListeningForScrollAreaEvents();
+  void StopListeningForScrollbarEvents();
+  void StopListeningForScrollAreaEvents();
+  void AddScrollbarEventListeners(dom::EventTarget* aScrollbar);
+  void RemoveScrollbarEventListeners(dom::EventTarget* aScrollbar);
+
+  void HoveredScrollbar(dom::Element* aScrollbar);
+
+  dom::Element* GetScrollbarContent(bool aVertical);
+  dom::Element* GetHorizontalScrollbar() { return GetScrollbarContent(false); }
+  dom::Element* GetVerticalScrollbar() { return GetScrollbarContent(true); }
+
+  nsIScrollbarMediator* const mScrollableFrame;
+  nsCOMPtr<dom::EventTarget> mHorizontalScrollbar;  // null while inactive
+  nsCOMPtr<dom::EventTarget> mVerticalScrollbar;    // null while inactive
+  nsCOMPtr<nsITimer> mFadeTimer;
+  uint32_t mNestedActivityCounter = 0;
+  // This boolean is true from the point activity starts to the point BeginFade
+  // runs, and effectively reflects the "active" attribute of the scrollbar.
+  bool mScrollbarEffectivelyVisible = false;
+  bool mListeningForScrollbarEvents = false;
+  bool mListeningForScrollAreaEvents = false;
+  bool mHScrollbarHovered = false;
+  bool mVScrollbarHovered = false;
+};
+
+}  // namespace layout
+}  // namespace mozilla
+
+#endif /* ScrollbarActivity_h___ */