1 files changed, 150 insertions, 0 deletions
diff --git a/layout/xul/nsScrollbarFrame.h b/layout/xul/nsScrollbarFrame.h
new file mode 100644
index 0000000000..4b48295f02
--- /dev/null
+++ b/layout/xul/nsScrollbarFrame.h
@@ -0,0 +1,150 @@
+/* -*- 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/. */
+
+//
+// nsScrollbarFrame
+//
+
+#ifndef nsScrollbarFrame_h__
+#define nsScrollbarFrame_h__
+
+#include "mozilla/Attributes.h"
+#include "mozilla/ScrollTypes.h"
+#include "nsContainerFrame.h"
+#include "nsIAnonymousContentCreator.h"
+
+class nsIScrollbarMediator;
+
+namespace mozilla {
+class PresShell;
+namespace dom {
+class Element;
+}
+}  // namespace mozilla
+
+nsIFrame* NS_NewScrollbarFrame(mozilla::PresShell* aPresShell,
+                               mozilla::ComputedStyle* aStyle);
+
+class nsScrollbarFrame final : public nsContainerFrame,
+                               public nsIAnonymousContentCreator {
+  using Element = mozilla::dom::Element;
+
+ public:
+  explicit nsScrollbarFrame(ComputedStyle* aStyle, nsPresContext* aPresContext)
+      : nsContainerFrame(aStyle, aPresContext, kClassID),
+        mSmoothScroll(false),
+        mScrollUnit(mozilla::ScrollUnit::DEVICE_PIXELS),
+        mDirection(0),
+        mIncrement(0),
+        mScrollbarMediator(nullptr),
+        mUpTopButton(nullptr),
+        mDownTopButton(nullptr),
+        mSlider(nullptr),
+        mThumb(nullptr),
+        mUpBottomButton(nullptr),
+        mDownBottomButton(nullptr) {}
+
+  NS_DECL_QUERYFRAME
+  NS_DECL_FRAMEARENA_HELPERS(nsScrollbarFrame)
+
+#ifdef DEBUG_FRAME_DUMP
+  nsresult GetFrameName(nsAString& aResult) const override {
+    return MakeFrameName(u"ScrollbarFrame"_ns, aResult);
+  }
+#endif
+
+  // nsIFrame overrides
+  nsresult AttributeChanged(int32_t aNameSpaceID, nsAtom* aAttribute,
+                            int32_t aModType) override;
+
+  NS_IMETHOD HandlePress(nsPresContext* aPresContext,
+                         mozilla::WidgetGUIEvent* aEvent,
+                         nsEventStatus* aEventStatus) override;
+
+  NS_IMETHOD HandleMultiplePress(nsPresContext* aPresContext,
+                                 mozilla::WidgetGUIEvent* aEvent,
+                                 nsEventStatus* aEventStatus,
+                                 bool aControlHeld) override;
+
+  MOZ_CAN_RUN_SCRIPT
+  NS_IMETHOD HandleDrag(nsPresContext* aPresContext,
+                        mozilla::WidgetGUIEvent* aEvent,
+                        nsEventStatus* aEventStatus) override;
+
+  NS_IMETHOD HandleRelease(nsPresContext* aPresContext,
+                           mozilla::WidgetGUIEvent* aEvent,
+                           nsEventStatus* aEventStatus) override;
+
+  mozilla::StyleScrollbarWidth ScrollbarWidth() const;
+  nscoord ScrollbarTrackSize() const;
+  nsSize ScrollbarMinSize() const;
+  bool IsHorizontal() const;
+
+  void Destroy(DestroyContext&) override;
+
+  void Init(nsIContent* aContent, nsContainerFrame* aParent,
+            nsIFrame* aPrevInFlow) override;
+
+  void Reflow(nsPresContext* aPresContext, ReflowOutput& aDesiredSize,
+              const ReflowInput& aReflowInput,
+              nsReflowStatus& aStatus) override;
+
+  void SetScrollbarMediatorContent(nsIContent* aMediator);
+  nsIScrollbarMediator* GetScrollbarMediator();
+
+  /**
+   * The following three methods set the value of mIncrement when a
+   * scrollbar button is pressed.
+   */
+  void SetIncrementToLine(int32_t aDirection);
+  void SetIncrementToPage(int32_t aDirection);
+  void SetIncrementToWhole(int32_t aDirection);
+
+  /**
+   * If aImplementsScrollByUnit is Yes then this uses mSmoothScroll,
+   * mScrollUnit, and mDirection and calls ScrollByUnit on the
+   * nsIScrollbarMediator. The return value is 0. This is better because it is
+   * more modern and the scroll frame can perform the scroll via apz for
+   * example. The old way below is still supported for xul trees. If
+   * aImplementsScrollByUnit is No this adds mIncrement to the current
+   * position and updates the curpos attribute obeying mSmoothScroll.
+   * @returns The new position after clamping, in CSS Pixels
+   * @note This method might destroy the frame, pres shell, and other objects.
+   */
+  enum class ImplementsScrollByUnit { Yes, No };
+  int32_t MoveToNewPosition(ImplementsScrollByUnit aImplementsScrollByUnit);
+  int32_t GetIncrement() { return mIncrement; }
+
+  // nsIAnonymousContentCreator
+  nsresult CreateAnonymousContent(nsTArray<ContentInfo>& aElements) override;
+  void AppendAnonymousContentTo(nsTArray<nsIContent*>& aElements,
+                                uint32_t aFilter) override;
+
+  void UpdateChildrenAttributeValue(nsAtom* aAttribute, bool aNotify);
+
+ protected:
+  bool mSmoothScroll;
+  mozilla::ScrollUnit mScrollUnit;
+  // Direction and multiple to scroll
+  int32_t mDirection;
+
+  // Amount to scroll, in CSSPixels
+  // Ignored in favour of mScrollUnit/mDirection for regular scroll frames.
+  // Trees use this though.
+  int32_t mIncrement;
+
+ private:
+  nsCOMPtr<nsIContent> mScrollbarMediator;
+
+  nsCOMPtr<Element> mUpTopButton;
+  nsCOMPtr<Element> mDownTopButton;
+  nsCOMPtr<Element> mSlider;
+  nsCOMPtr<Element> mThumb;
+  nsCOMPtr<Element> mUpBottomButton;
+  nsCOMPtr<Element> mDownBottomButton;
+};  // class nsScrollbarFrame
+
+#endif