Add m-esr52 at 52.6.0

1 files changed, 480 insertions, 0 deletions

diff --git a/layout/generic/nsIScrollableFrame.h b/layout/generic/nsIScrollableFrame.h
new file mode 100644
index 0000000000..b7e3caf46a
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+++ b/layout/generic/nsIScrollableFrame.h
@@ -0,0 +1,480 @@
+/* -*- 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/. */
+
+/*
+ * interface that provides scroll APIs implemented by scrollable frames
+ */
+
+#ifndef nsIScrollFrame_h___
+#define nsIScrollFrame_h___
+
+#include "nsCoord.h"
+#include "DisplayItemClip.h"
+#include "ScrollbarStyles.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/gfx/Point.h"
+#include "nsIScrollbarMediator.h"
+#include "Units.h"
+#include "FrameMetrics.h"
+
+#define NS_DEFAULT_VERTICAL_SCROLL_DISTANCE   3
+#define NS_DEFAULT_HORIZONTAL_SCROLL_DISTANCE 5
+
+class nsBoxLayoutState;
+class nsIScrollPositionListener;
+class nsIFrame;
+class nsPresContext;
+class nsIContent;
+class nsRenderingContext;
+class nsIAtom;
+class nsDisplayListBuilder;
+
+namespace mozilla {
+struct ContainerLayerParameters;
+namespace layers {
+class Layer;
+} // namespace layers
+} // namespace mozilla
+
+/**
+ * Interface for frames that are scrollable. This interface exposes
+ * APIs for examining scroll state, observing changes to scroll state,
+ * and triggering scrolling.
+ */
+class nsIScrollableFrame : public nsIScrollbarMediator {
+public:
+  typedef mozilla::CSSIntPoint CSSIntPoint;
+  typedef mozilla::ContainerLayerParameters ContainerLayerParameters;
+  typedef mozilla::layers::FrameMetrics FrameMetrics;
+  typedef mozilla::layers::ScrollSnapInfo ScrollSnapInfo;
+
+  NS_DECL_QUERYFRAME_TARGET(nsIScrollableFrame)
+
+  /**
+   * Get the frame for the content that we are scrolling within
+   * this scrollable frame.
+   */
+  virtual nsIFrame* GetScrolledFrame() const = 0;
+
+  /**
+   * Get the styles (NS_STYLE_OVERFLOW_SCROLL, NS_STYLE_OVERFLOW_HIDDEN,
+   * or NS_STYLE_OVERFLOW_AUTO) governing the horizontal and vertical
+   * scrollbars for this frame.
+   */
+  virtual mozilla::ScrollbarStyles GetScrollbarStyles() const = 0;
+
+  enum { HORIZONTAL = 0x01, VERTICAL = 0x02 };
+  /**
+   * Return the scrollbars which are visible. It's OK to call this during reflow
+   * of the scrolled contents, in which case it will reflect the current
+   * assumptions about scrollbar visibility.
+   */
+  virtual uint32_t GetScrollbarVisibility() const = 0;
+  /**
+   * Returns the directions in which scrolling is perceived to be allowed.
+   * A direction is perceived to be allowed if there is a visible scrollbar
+   * for that direction or if the scroll range is at least one device pixel.
+   */
+  uint32_t GetPerceivedScrollingDirections() const;
+  /**
+   * Return the actual sizes of all possible scrollbars. Returns 0 for scrollbar
+   * positions that don't have a scrollbar or where the scrollbar is not visible.
+   * Do not call this while this frame's descendants are being reflowed, it won't be
+   * accurate.
+   */
+  virtual nsMargin GetActualScrollbarSizes() const = 0;
+  /**
+   * Return the sizes of all scrollbars assuming that any scrollbars that could
+   * be visible due to overflowing content, are. This can be called during reflow
+   * of the scrolled contents.
+   */
+  virtual nsMargin GetDesiredScrollbarSizes(nsBoxLayoutState* aState) = 0;
+  /**
+   * Return the sizes of all scrollbars assuming that any scrollbars that could
+   * be visible due to overflowing content, are. This can be called during reflow
+   * of the scrolled contents.
+   */
+  virtual nsMargin GetDesiredScrollbarSizes(nsPresContext* aPresContext,
+                                            nsRenderingContext* aRC) = 0;
+  /**
+   * Return the width for non-disappearing scrollbars.
+   */
+  virtual nscoord
+  GetNondisappearingScrollbarWidth(nsPresContext* aPresContext,
+                                   nsRenderingContext* aRC,
+                                   mozilla::WritingMode aWM) = 0;
+  /**
+   * GetScrolledRect is designed to encapsulate deciding which
+   * directions of overflow should be reachable by scrolling and which
+   * should not.  Callers should NOT depend on it having any particular
+   * behavior (although nsXULScrollFrame currently does).
+   *
+   * This should only be called when the scrolled frame has been
+   * reflowed with the scroll port size given in mScrollPort.
+   *
+   * Currently it allows scrolling down and to the right for
+   * nsHTMLScrollFrames with LTR directionality and for all
+   * nsXULScrollFrames, and allows scrolling down and to the left for
+   * nsHTMLScrollFrames with RTL directionality.
+   */
+  virtual nsRect GetScrolledRect() const = 0;
+  /**
+   * Get the area of the scrollport relative to the origin of this frame's
+   * border-box.
+   * This is the area of this frame minus border and scrollbars.
+   */
+  virtual nsRect GetScrollPortRect() const = 0;
+  /**
+   * Get the offset of the scrollport origin relative to the scrolled
+   * frame origin. Typically the position will be non-negative.
+   * This will always be a multiple of device pixels.
+   */
+  virtual nsPoint GetScrollPosition() const = 0;
+  /**
+   * As GetScrollPosition(), but uses the top-right as origin for RTL frames. 
+   */
+  virtual nsPoint GetLogicalScrollPosition() const = 0;
+  /**
+   * Get the area that must contain the scroll position. Typically
+   * (but not always, e.g. for RTL content) x and y will be 0, and
+   * width or height will be nonzero if the content can be scrolled in
+   * that direction. Since scroll positions must be a multiple of
+   * device pixels, the range extrema will also be a multiple of
+   * device pixels.
+   */
+  virtual nsRect GetScrollRange() const = 0;
+  /**
+   * Get the size of the scroll port to use when clamping the scroll
+   * position.
+   */
+  virtual nsSize GetScrollPositionClampingScrollPortSize() const = 0;
+  /**
+   * Return how much we would try to scroll by in each direction if
+   * asked to scroll by one "line" vertically and horizontally.
+   */
+  virtual nsSize GetLineScrollAmount() const = 0;
+  /**
+   * Return how much we would try to scroll by in each direction if
+   * asked to scroll by one "page" vertically and horizontally.
+   */
+  virtual nsSize GetPageScrollAmount() const = 0;
+
+  /**
+   * When a scroll operation is requested, we ask for instant, smooth,
+   * smooth msd, or normal scrolling.
+   *
+   * SMOOTH scrolls have a symmetrical acceleration and deceleration curve
+   * modeled with a set of splines that guarantee that the destination will be 
+   * reached over a fixed time interval.  SMOOTH will only be smooth if smooth
+   * scrolling is actually enabled.  This behavior is utilized by keyboard and
+   * mouse wheel scrolling events.
+   *
+   * SMOOTH_MSD implements a physically based model that approximates the
+   * behavior of a mass-spring-damper system.  SMOOTH_MSD scrolls have a
+   * non-symmetrical acceleration and deceleration curve, can potentially
+   * overshoot the destination on intermediate frames, and complete over a
+   * variable time interval.  SMOOTH_MSD will only be smooth if cssom-view
+   * smooth-scrolling is enabled.
+   *
+   * INSTANT is always synchronous, NORMAL can be asynchronous.
+   *
+   * If an INSTANT scroll request happens while a SMOOTH or async scroll is
+   * already in progress, the async scroll is interrupted and we instantly
+   * scroll to the destination.
+   *
+   * If an INSTANT or SMOOTH scroll request happens while a SMOOTH_MSD scroll
+   * is already in progress, the SMOOTH_MSD scroll is interrupted without
+   * first scrolling to the destination.
+   */
+  enum ScrollMode { INSTANT, SMOOTH, SMOOTH_MSD, NORMAL };
+  /**
+   * Some platforms (OSX) may generate additional scrolling events even
+   * after the user has stopped scrolling, simulating a momentum scrolling
+   * effect resulting from fling gestures.
+   * SYNTHESIZED_MOMENTUM_EVENT indicates that the scrolling is being requested
+   * by such a synthesized event and may be ignored if another scroll has
+   * been started since the last actual user input.
+   */
+  enum ScrollMomentum { NOT_MOMENTUM, SYNTHESIZED_MOMENTUM_EVENT };
+  /**
+   * @note This method might destroy the frame, pres shell and other objects.
+   * Clamps aScrollPosition to GetScrollRange and sets the scroll position
+   * to that value.
+   * @param aRange If non-null, specifies area which contains aScrollPosition
+   * and can be used for choosing a performance-optimized scroll position.
+   * Any point within this area can be chosen.
+   * The choosen point will be as close as possible to aScrollPosition.
+   */
+  virtual void ScrollTo(nsPoint aScrollPosition, ScrollMode aMode,
+                        const nsRect* aRange = nullptr,
+                        nsIScrollbarMediator::ScrollSnapMode aSnap
+                          = nsIScrollbarMediator::DISABLE_SNAP) = 0;
+  /**
+   * @note This method might destroy the frame, pres shell and other objects.
+   * Scrolls to a particular position in integer CSS pixels.
+   * Keeps the exact current horizontal or vertical position if the current
+   * position, rounded to CSS pixels, matches aScrollPosition. If
+   * aScrollPosition.x/y is different from the current CSS pixel position,
+   * makes sure we only move in the direction given by the difference.
+   *
+   * When aMode is SMOOTH, INSTANT, or NORMAL, GetScrollPositionCSSPixels (the
+   * scroll position after rounding to CSS pixels) will be exactly
+   * aScrollPosition at the end of the scroll animation.
+   *
+   * When aMode is SMOOTH_MSD, intermediate animation frames may be outside the
+   * range and / or moving in any direction; GetScrollPositionCSSPixels will be
+   * exactly aScrollPosition at the end of the scroll animation unless the
+   * SMOOTH_MSD animation is interrupted.
+   */
+  virtual void ScrollToCSSPixels(const CSSIntPoint& aScrollPosition,
+                                 nsIScrollableFrame::ScrollMode aMode
+                                   = nsIScrollableFrame::INSTANT) = 0;
+  /**
+   * @note This method might destroy the frame, pres shell and other objects.
+   * Scrolls to a particular position in float CSS pixels.
+   * This does not guarantee that GetScrollPositionCSSPixels equals
+   * aScrollPosition afterward. It tries to scroll as close to
+   * aScrollPosition as possible while scrolling by an integer
+   * number of layer pixels (so the operation is fast and looks clean).
+   */
+  virtual void ScrollToCSSPixelsApproximate(const mozilla::CSSPoint& aScrollPosition,
+                                            nsIAtom *aOrigin = nullptr) = 0;
+
+  /**
+   * Returns the scroll position in integer CSS pixels, rounded to the nearest
+   * pixel.
+   */
+  virtual CSSIntPoint GetScrollPositionCSSPixels() = 0;
+  /**
+   * When scrolling by a relative amount, we can choose various units.
+   */
+  enum ScrollUnit { DEVICE_PIXELS, LINES, PAGES, WHOLE };
+  /**
+   * @note This method might destroy the frame, pres shell and other objects.
+   * Modifies the current scroll position by aDelta units given by aUnit,
+   * clamping it to GetScrollRange. If WHOLE is specified as the unit,
+   * content is scrolled all the way in the direction(s) given by aDelta.
+   * @param aOverflow if non-null, returns the amount that scrolling
+   * was clamped by in each direction (how far we moved the scroll position
+   * to bring it back into the legal range). This is never negative. The
+   * values are in device pixels.
+   */
+  virtual void ScrollBy(nsIntPoint aDelta, ScrollUnit aUnit, ScrollMode aMode,
+                        nsIntPoint* aOverflow = nullptr,
+                        nsIAtom* aOrigin = nullptr,
+                        ScrollMomentum aMomentum = NOT_MOMENTUM,
+                        nsIScrollbarMediator::ScrollSnapMode aSnap
+                          = nsIScrollbarMediator::DISABLE_SNAP) = 0;
+
+  /**
+   * Perform scroll snapping, possibly resulting in a smooth scroll to
+   * maintain the scroll snap position constraints.  Velocity sampled from
+   * main thread scrolling is used to determine best matching snap point
+   * when called after a fling gesture on a trackpad or mouse wheel.
+   */
+  virtual void ScrollSnap() = 0;
+
+  /**
+   * @note This method might destroy the frame, pres shell and other objects.
+   * This tells the scroll frame to try scrolling to the scroll
+   * position that was restored from the history. This must be called
+   * at least once after state has been restored. It is called by the
+   * scrolled frame itself during reflow, but sometimes state can be
+   * restored after reflows are done...
+   * XXX should we take an aMode parameter here? Currently it's instant.
+   */
+  virtual void ScrollToRestoredPosition() = 0;
+
+  /**
+   * Add a scroll position listener. This listener must be removed
+   * before it is destroyed.
+   */
+  virtual void AddScrollPositionListener(nsIScrollPositionListener* aListener) = 0;
+  /**
+   * Remove a scroll position listener.
+   */
+  virtual void RemoveScrollPositionListener(nsIScrollPositionListener* aListener) = 0;
+
+  /**
+   * Internal method used by scrollbars to notify their scrolling
+   * container of changes.
+   */
+  virtual void CurPosAttributeChanged(nsIContent* aChild) = 0;
+
+  /**
+   * Allows the docshell to request that the scroll frame post an event
+   * after being restored from history.
+   */
+  NS_IMETHOD PostScrolledAreaEventForCurrentArea() = 0;
+
+  /**
+   * Returns true if this scrollframe is being "actively scrolled".
+   * This basically means that we should allocate resources in the
+   * expectation that scrolling is going to happen.
+   */
+  virtual bool IsScrollingActive(nsDisplayListBuilder* aBuilder) = 0;
+  /**
+   * Returns true if the scrollframe is currently processing an async
+   * or smooth scroll.
+   */
+  virtual bool IsProcessingAsyncScroll() = 0;
+  /**
+   * Call this when the layer(s) induced by active scrolling are being
+   * completely redrawn.
+   */
+  virtual void ResetScrollPositionForLayerPixelAlignment() = 0;
+  /**
+   * Was the current presentation state for this frame restored from history?
+   */
+  virtual bool DidHistoryRestore() const = 0;
+  /**
+   * Clear the flag so that DidHistoryRestore() returns false until the next
+   * RestoreState call.
+   * @see nsIStatefulFrame::RestoreState
+   */
+  virtual void ClearDidHistoryRestore() = 0;
+  /**
+   * Determine if the passed in rect is nearly visible according to the frame
+   * visibility heuristics for how close it is to the visible scrollport.
+   */
+  virtual bool IsRectNearlyVisible(const nsRect& aRect) = 0;
+ /**
+  * Expand the given rect taking into account which directions we can scroll
+  * and how far we want to expand for frame visibility purposes.
+  */
+  virtual nsRect ExpandRectToNearlyVisible(const nsRect& aRect) const = 0;
+  /**
+   * Returns the origin that triggered the last instant scroll. Will equal
+   * nsGkAtoms::apz when the compositor's replica frame metrics includes the
+   * latest instant scroll.
+   */
+  virtual nsIAtom* LastScrollOrigin() = 0;
+  /**
+   * Sets a flag on the scrollframe that indicates the current scroll origin
+   * has been sent over in a layers transaction, and subsequent changes to
+   * the scroll position by "weaker" origins are permitted to overwrite the
+   * the scroll origin. Scroll origins that nsLayoutUtils::CanScrollOriginClobberApz
+   * returns false for are considered "weaker" than scroll origins for which
+   * that function returns true.
+   */
+  virtual void AllowScrollOriginDowngrade() = 0;
+  /**
+   * Returns the origin that triggered the last smooth scroll.
+   * Will equal nsGkAtoms::apz when the compositor's replica frame
+   * metrics includes the latest smooth scroll.  The compositor will always
+   * perform an instant scroll prior to instantiating any smooth scrolls
+   * if LastScrollOrigin and LastSmoothScrollOrigin indicate that
+   * an instant scroll and a smooth scroll have occurred since the last
+   * replication of the frame metrics.
+   *
+   * This is set to nullptr to when the compositor thread acknowledges that
+   * the smooth scroll has been started.  If the smooth scroll has been stomped
+   * by an instant scroll before the smooth scroll could be started by the
+   * compositor, this is set to nullptr to clear the smooth scroll.
+   */
+  virtual nsIAtom* LastSmoothScrollOrigin() = 0;
+  /**
+   * Returns the current generation counter for the scroll. This counter
+   * increments every time the scroll position is set.
+   */
+  virtual uint32_t CurrentScrollGeneration() = 0;
+  /**
+   * LastScrollDestination returns the destination of the most recently
+   * requested smooth scroll animation.
+   */
+  virtual nsPoint LastScrollDestination() = 0;
+  /**
+   * Clears the "origin of last scroll" property stored in this frame, if
+   * the generation counter passed in matches the current scroll generation
+   * counter.
+   */
+  virtual void ResetScrollInfoIfGeneration(uint32_t aGeneration) = 0;
+  /**
+   * Determine whether it is desirable to be able to asynchronously scroll this
+   * scroll frame.
+   */
+  virtual bool WantAsyncScroll() const = 0;
+  /**
+   * aLayer's animated geometry root is this frame. If there needs to be a
+   * ScrollMetadata contributed by this frame, append it to aOutput.
+   */
+  virtual mozilla::Maybe<mozilla::layers::ScrollMetadata> ComputeScrollMetadata(
+    mozilla::layers::Layer* aLayer,
+    nsIFrame* aContainerReferenceFrame,
+    const ContainerLayerParameters& aParameters,
+    const mozilla::DisplayItemClip* aClip) const = 0;
+
+  /**
+   * If this scroll frame is ignoring viewporting clipping
+   */
+  virtual bool IsIgnoringViewportClipping() const = 0;
+
+  /**
+   * Mark the scrollbar frames for reflow.
+   */
+  virtual void MarkScrollbarsDirtyForReflow() const = 0;
+
+  virtual void SetTransformingByAPZ(bool aTransforming) = 0;
+  virtual bool IsTransformingByAPZ() const = 0;
+
+  /**
+   * Notify this scroll frame that it can be scrolled by APZ. In particular,
+   * this is called *after* the APZ code has created an APZC for this scroll
+   * frame and verified that it is not a scrollinfo layer. Therefore, setting an
+   * async transform on it is actually user visible.
+   */
+  virtual void SetScrollableByAPZ(bool aScrollable) = 0;
+
+  /**
+   * Notify this scroll frame that it can be zoomed by APZ.
+   */
+  virtual void SetZoomableByAPZ(bool aZoomable) = 0;
+
+  /**
+   * Whether or not this frame uses containerful scrolling.
+   */
+  virtual bool UsesContainerScrolling() const = 0;
+
+  /**
+   * Determine if we should build a scrollable layer for this scroll frame and
+   * return the result. It will also record this result on the scroll frame.
+   * Pass the dirty rect in aDirtyRect. On return it will be set to the
+   * displayport if there is one (ie the dirty rect that should be used).
+   * This function may create a display port where one did not exist before if
+   * aAllowCreateDisplayPort is true. It is only allowed to be false if there
+   * has been a call with it set to true before on the same paint.
+   */
+  virtual bool DecideScrollableLayer(nsDisplayListBuilder* aBuilder,
+                                     nsRect* aDirtyRect,
+                                     bool aAllowCreateDisplayPort) = 0;
+
+  /**
+   * Notification that this scroll frame is getting its frame visibility updated.
+   */
+  virtual void NotifyApproximateFrameVisibilityUpdate() = 0;
+
+  /**
+   * Returns true if this scroll frame had a display port at the last frame
+   * visibility update and fills in aDisplayPort with that displayport. Returns
+   * false otherwise, and doesn't touch aDisplayPort.
+   */
+  virtual bool GetDisplayPortAtLastApproximateFrameVisibilityUpdate(nsRect* aDisplayPort) = 0;
+
+  /**
+   * This is called when a descendant scrollframe's has its displayport expired.
+   * This function will check to see if this scrollframe may safely expire its
+   * own displayport and schedule a timer to do that if it is safe.
+   */
+  virtual void TriggerDisplayPortExpiration() = 0;
+
+  /**
+   * Returns information required to determine where to snap to after a scroll.
+   */
+  virtual ScrollSnapInfo GetScrollSnapInfo() const = 0;
+
+  virtual void SetScrollsClipOnUnscrolledOutOfFlow() = 0;
+};
+
+#endif