Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream

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

1 files changed, 522 insertions, 0 deletions

diff --git a/layout/base/nsChangeHint.h b/layout/base/nsChangeHint.h
new file mode 100644
index 0000000000..9137f95122
--- /dev/null
+++ b/layout/base/nsChangeHint.h
@@ -0,0 +1,522 @@
+/* -*- 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/. */
+
+/* constants for what needs to be recomputed in response to style changes */
+
+#ifndef nsChangeHint_h___
+#define nsChangeHint_h___
+
+#include "mozilla/Types.h"
+#include "mozilla/Assertions.h"
+
+// Defines for various style related constants
+
+enum nsChangeHint : uint32_t {
+  nsChangeHint_Empty = 0,
+
+  // change was visual only (e.g., COLOR=)
+  // Invalidates all descendant frames (including following
+  // placeholders to out-of-flow frames).
+  nsChangeHint_RepaintFrame = 1 << 0,
+
+  // For reflow, we want flags to give us arbitrary FrameNeedsReflow behavior.
+  // just do a FrameNeedsReflow.
+  nsChangeHint_NeedReflow = 1 << 1,
+
+  // Invalidate intrinsic widths on the frame's ancestors.  Must not be set
+  // without setting nsChangeHint_NeedReflow.
+  nsChangeHint_ClearAncestorIntrinsics = 1 << 2,
+
+  // Invalidate intrinsic widths on the frame's descendants.  Must not be set
+  // without also setting nsChangeHint_ClearAncestorIntrinsics,
+  // nsChangeHint_NeedDirtyReflow and nsChangeHint_NeedReflow.
+  nsChangeHint_ClearDescendantIntrinsics = 1 << 3,
+
+  // Force unconditional reflow of all descendants.  Must not be set without
+  // setting nsChangeHint_NeedReflow, but can be set regardless of whether the
+  // Clear*Intrinsics flags are set.
+  nsChangeHint_NeedDirtyReflow = 1 << 4,
+
+  // The currently shown mouse cursor needs to be updated
+  nsChangeHint_UpdateCursor = 1 << 5,
+
+  /**
+   * Used when the computed value (a URI) of one or more of an element's
+   * filter/mask/clip/etc CSS properties changes, causing the element's frame
+   * to start/stop referencing (or reference different) SVG resource elements.
+   * (_Not_ used to handle changes to referenced resource elements.) Using this
+   * hint results in SVGObserverUtils::UpdateEffects being called on the
+   * element's frame.
+   */
+  nsChangeHint_UpdateEffects = 1 << 6,
+
+  /**
+   * Visual change only, but the change can be handled entirely by
+   * updating the layer(s) for the frame.
+   * Updates all descendants (including following placeholders to out-of-flows).
+   */
+  nsChangeHint_UpdateOpacityLayer = 1 << 7,
+  /**
+   * Updates all descendants. Any placeholder descendants' out-of-flows
+   * are also descendants of the transformed frame, so they're updated.
+   */
+  nsChangeHint_UpdateTransformLayer = 1 << 8,
+
+  /**
+   * Change requires frame change (e.g., display:).
+   * Reconstructs all frame descendants, including following placeholders
+   * to out-of-flows.
+   *
+   * Note that this subsumes all the other change hints. (see
+   * RestyleManager::ProcessRestyledFrames for details).
+   */
+  nsChangeHint_ReconstructFrame = 1 << 9,
+
+  /**
+   * The frame's overflow area has changed. Does not update any descendant
+   * frames.
+   */
+  nsChangeHint_UpdateOverflow = 1 << 10,
+
+  /**
+   * The overflow area of the frame and all of its descendants has changed. This
+   * can happen through a text-decoration change.
+   */
+  nsChangeHint_UpdateSubtreeOverflow = 1 << 11,
+
+  /**
+   * The frame's overflow area has changed, through a change in its transform.
+   * In other words, the frame's pre-transform overflow is unchanged, but
+   * its post-transform overflow has changed, and thus its effect on its
+   * parent's overflow has changed.  If the pre-transform overflow has
+   * changed, see nsChangeHint_UpdateOverflow.
+   * Does not update any descendant frames.
+   */
+  nsChangeHint_UpdatePostTransformOverflow = 1 << 12,
+
+  /**
+   * This frame's effect on its parent's overflow area has changed.
+   * (But neither its pre-transform nor post-transform overflow have
+   * changed; if those are the case, see
+   * nsChangeHint_UpdatePostTransformOverflow.)
+   */
+  nsChangeHint_UpdateParentOverflow = 1 << 13,
+
+  /**
+   * The children-only transform of an SVG frame changed, requiring overflows to
+   * be updated.
+   */
+  nsChangeHint_ChildrenOnlyTransform = 1 << 14,
+
+  /**
+   * The frame's offsets have changed, while its dimensions might have
+   * changed as well.  This hint is used for positioned frames if their
+   * offset changes.  If we decide that the dimensions are likely to
+   * change, this will trigger a reflow.
+   *
+   * Note that this should probably be used in combination with
+   * nsChangeHint_UpdateOverflow in order to get the overflow areas of
+   * the ancestors updated as well.
+   */
+  nsChangeHint_RecomputePosition = 1 << 15,
+
+  /**
+   * Behaves like ReconstructFrame, but only if the frame has descendants
+   * that are absolutely or fixed position. Use this hint when a style change
+   * has changed whether the frame is a container for fixed-pos or abs-pos
+   * elements, but reframing is otherwise not needed.
+   *
+   * Note that ComputedStyle::CalcStyleDifference adjusts results
+   * returned by style struct CalcDifference methods to return this hint
+   * only if there was a change to whether the element's overall style
+   * indicates that it establishes a containing block.
+   */
+  nsChangeHint_UpdateContainingBlock = 1 << 16,
+
+  /**
+   * This change hint has *no* change handling behavior.  However, it
+   * exists to be a non-inherited hint, because when the border-style
+   * changes, and it's inherited by a child, that might require a reflow
+   * due to the border-width change on the child.
+   */
+  nsChangeHint_BorderStyleNoneChange = 1 << 17,
+
+  /**
+   * This will schedule an invalidating paint. This is useful if something
+   * has changed which will be invalidated by DLBI.
+   */
+  nsChangeHint_SchedulePaint = 1 << 18,
+
+  /**
+   * A hint reflecting that style data changed with no change handling
+   * behavior.  We need to return this, rather than nsChangeHint(0),
+   * so that certain optimizations that manipulate the style tree are
+   * correct.
+   *
+   * nsChangeHint_NeutralChange must be returned by CalcDifference on a given
+   * style struct if the data in the style structs are meaningfully different
+   * and if no other change hints are returned.  If any other change hints are
+   * set, then nsChangeHint_NeutralChange need not also be included, but it is
+   * safe to do so.  (An example of style structs having non-meaningfully
+   * different data would be cached information that would be re-calculated
+   * to the same values, such as nsStyleBorder::mSubImages.)
+   */
+  nsChangeHint_NeutralChange = 1 << 19,
+
+  /**
+   * This will cause rendering observers to be invalidated.
+   */
+  nsChangeHint_InvalidateRenderingObservers = 1 << 20,
+
+  /**
+   * Indicates that the reflow changes the size or position of the
+   * element, and thus the reflow must start from at least the frame's
+   * parent.  Must be not be set without also setting nsChangeHint_NeedReflow.
+   * And consider adding nsChangeHint_ClearAncestorIntrinsics if needed.
+   */
+  nsChangeHint_ReflowChangesSizeOrPosition = 1 << 21,
+
+  /**
+   * Indicates that the style changes the computed BSize --- e.g. 'height'.
+   * Must not be set without also setting nsChangeHint_NeedReflow.
+   */
+  nsChangeHint_UpdateComputedBSize = 1 << 22,
+
+  /**
+   * Indicates that the 'opacity' property changed between 1 and non-1.
+   *
+   * Used as extra data for handling UpdateOpacityLayer hints.
+   *
+   * Note that we do not send this hint if the non-1 value was 0.99 or
+   * greater, since in that case we send a RepaintFrame hint instead.
+   */
+  nsChangeHint_UpdateUsesOpacity = 1 << 23,
+
+  /**
+   * Indicates that the 'background-position' property changed.
+   * Regular frames can invalidate these changes using DLBI, but
+   * for some frame types we need to repaint the whole frame because
+   * the frame does not build individual background image display items
+   * for each background layer.
+   */
+  nsChangeHint_UpdateBackgroundPosition = 1 << 24,
+
+  /**
+   * Indicates that a frame has changed to or from having the CSS
+   * transform property set.
+   */
+  nsChangeHint_AddOrRemoveTransform = 1 << 25,
+
+  /**
+   * Indicates that the presence of scrollbars might have changed.
+   *
+   * This happens when at least one of overflow-{x,y} properties changed.
+   *
+   * In most cases, this is equivalent to nsChangeHint_ReconstructFrame. But
+   * in some special cases where the change is really targeting the viewport's
+   * scrollframe, this is instead equivalent to nsChangeHint_AllReflowHints
+   * (because the viewport always has an associated scrollframe).
+   */
+  nsChangeHint_ScrollbarChange = 1 << 26,
+
+  /**
+   *  Indicates that there has been a colspan or rowspan attribute change
+   *  on the cells of a table.
+   */
+  nsChangeHint_UpdateTableCellSpans = 1 << 27,
+
+  /**
+   * Indicates that the visiblity property changed.
+   * This change hint is used for skip restyling for animations on
+   * visibility:hidden elements in the case where the elements have no visible
+   * descendants.
+   */
+  nsChangeHint_VisibilityChange = 1u << 28,
+
+  // IMPORTANT NOTE: When adding a new hint, you will need to add it to
+  // one of:
+  //
+  //   * nsChangeHint_Hints_NeverHandledForDescendants
+  //   * nsChangeHint_Hints_AlwaysHandledForDescendants
+  //   * nsChangeHint_Hints_SometimesHandledForDescendants
+  //
+  // and you also may need to handle it in NS_HintsNotHandledForDescendantsIn.
+  //
+  // Please also add it to RestyleManager::ChangeHintToString and
+  // modify nsChangeHint_AllHints below accordingly.
+
+  /**
+   * Dummy hint value for all hints. It exists for compile time check.
+   */
+  nsChangeHint_AllHints = uint32_t((1ull << 29) - 1),
+};
+
+// Redefine these operators to return nothing. This will catch any use
+// of these operators on hints. We should not be using these operators
+// on nsChangeHints
+inline void operator<(nsChangeHint s1, nsChangeHint s2) {}
+inline void operator>(nsChangeHint s1, nsChangeHint s2) {}
+inline void operator!=(nsChangeHint s1, nsChangeHint s2) {}
+inline void operator==(nsChangeHint s1, nsChangeHint s2) {}
+inline void operator<=(nsChangeHint s1, nsChangeHint s2) {}
+inline void operator>=(nsChangeHint s1, nsChangeHint s2) {}
+
+// Operators on nsChangeHints
+
+// Returns true iff the second hint contains all the hints of the first hint
+inline bool NS_IsHintSubset(nsChangeHint aSubset, nsChangeHint aSuperSet) {
+  return (aSubset & aSuperSet) == aSubset;
+}
+
+// The functions below need an integral type to cast to to avoid
+// infinite recursion.
+typedef decltype(nsChangeHint(0) + nsChangeHint(0)) nsChangeHint_size_t;
+
+inline nsChangeHint constexpr operator|(nsChangeHint aLeft,
+                                        nsChangeHint aRight) {
+  return nsChangeHint(nsChangeHint_size_t(aLeft) | nsChangeHint_size_t(aRight));
+}
+
+inline nsChangeHint constexpr operator&(nsChangeHint aLeft,
+                                        nsChangeHint aRight) {
+  return nsChangeHint(nsChangeHint_size_t(aLeft) & nsChangeHint_size_t(aRight));
+}
+
+inline nsChangeHint& operator|=(nsChangeHint& aLeft, nsChangeHint aRight) {
+  return aLeft = aLeft | aRight;
+}
+
+inline nsChangeHint& operator&=(nsChangeHint& aLeft, nsChangeHint aRight) {
+  return aLeft = aLeft & aRight;
+}
+
+inline nsChangeHint constexpr operator~(nsChangeHint aArg) {
+  return nsChangeHint(~nsChangeHint_size_t(aArg));
+}
+
+inline nsChangeHint constexpr operator^(nsChangeHint aLeft,
+                                        nsChangeHint aRight) {
+  return nsChangeHint(nsChangeHint_size_t(aLeft) ^ nsChangeHint_size_t(aRight));
+}
+
+inline nsChangeHint operator^=(nsChangeHint& aLeft, nsChangeHint aRight) {
+  return aLeft = aLeft ^ aRight;
+}
+
+/**
+ * We have an optimization when processing change hints which prevents
+ * us from visiting the descendants of a node when a hint on that node
+ * is being processed.  This optimization does not apply in some of the
+ * cases where applying a hint to an element does not necessarily result
+ * in the same hint being handled on the descendants.
+ */
+
+// The change hints that are always handled for descendants.
+#define nsChangeHint_Hints_AlwaysHandledForDescendants                     \
+  (nsChangeHint_ClearDescendantIntrinsics | nsChangeHint_NeedDirtyReflow | \
+   nsChangeHint_NeutralChange | nsChangeHint_ReconstructFrame |            \
+   nsChangeHint_RepaintFrame | nsChangeHint_SchedulePaint |                \
+   nsChangeHint_UpdateCursor | nsChangeHint_UpdateSubtreeOverflow |        \
+   nsChangeHint_VisibilityChange)
+
+// The change hints that are never handled for descendants.
+#define nsChangeHint_Hints_NeverHandledForDescendants                         \
+  (nsChangeHint_BorderStyleNoneChange | nsChangeHint_ChildrenOnlyTransform |  \
+   nsChangeHint_ScrollbarChange | nsChangeHint_InvalidateRenderingObservers | \
+   nsChangeHint_RecomputePosition | nsChangeHint_UpdateBackgroundPosition |   \
+   nsChangeHint_UpdateComputedBSize | nsChangeHint_UpdateContainingBlock |    \
+   nsChangeHint_UpdateEffects | nsChangeHint_UpdateOpacityLayer |             \
+   nsChangeHint_UpdateOverflow | nsChangeHint_UpdateParentOverflow |          \
+   nsChangeHint_UpdatePostTransformOverflow |                                 \
+   nsChangeHint_UpdateTableCellSpans | nsChangeHint_UpdateTransformLayer |    \
+   nsChangeHint_UpdateUsesOpacity | nsChangeHint_AddOrRemoveTransform)
+
+// The change hints that are sometimes considered to be handled for descendants.
+#define nsChangeHint_Hints_SometimesHandledForDescendants           \
+  (nsChangeHint_ClearAncestorIntrinsics | nsChangeHint_NeedReflow | \
+   nsChangeHint_ReflowChangesSizeOrPosition)
+
+static_assert(!(nsChangeHint_Hints_AlwaysHandledForDescendants &
+                nsChangeHint_Hints_NeverHandledForDescendants) &&
+                  !(nsChangeHint_Hints_AlwaysHandledForDescendants &
+                    nsChangeHint_Hints_SometimesHandledForDescendants) &&
+                  !(nsChangeHint_Hints_NeverHandledForDescendants &
+                    nsChangeHint_Hints_SometimesHandledForDescendants) &&
+                  !(nsChangeHint_AllHints ^
+                    nsChangeHint_Hints_AlwaysHandledForDescendants ^
+                    nsChangeHint_Hints_NeverHandledForDescendants ^
+                    nsChangeHint_Hints_SometimesHandledForDescendants),
+              "change hints must be present in exactly one of "
+              "nsChangeHint_Hints_{Always,Never,Sometimes}"
+              "HandledForDescendants");
+
+// The most hints that NS_HintsNotHandledForDescendantsIn could possibly return:
+#define nsChangeHint_Hints_NotHandledForDescendants \
+  (nsChangeHint_Hints_NeverHandledForDescendants |  \
+   nsChangeHint_Hints_SometimesHandledForDescendants)
+
+// Redefine the old NS_STYLE_HINT constants in terms of the new hint structure
+#define NS_STYLE_HINT_VISUAL \
+  nsChangeHint(nsChangeHint_RepaintFrame | nsChangeHint_SchedulePaint)
+#define nsChangeHint_AllReflowHints                                        \
+  nsChangeHint(                                                            \
+      nsChangeHint_NeedReflow | nsChangeHint_ReflowChangesSizeOrPosition | \
+      nsChangeHint_ClearAncestorIntrinsics |                               \
+      nsChangeHint_ClearDescendantIntrinsics | nsChangeHint_NeedDirtyReflow)
+
+// Below are the change hints that we send for ISize & BSize changes.
+// Each is similar to nsChangeHint_AllReflowHints with a few changes.
+
+// * For an ISize change, we send nsChangeHint_AllReflowHints, with two bits
+// excluded: nsChangeHint_ClearDescendantIntrinsics (because an ancestor's
+// inline-size change can't affect descendant intrinsic sizes), and
+// nsChangeHint_NeedDirtyReflow (because ISize changes don't need to *force*
+// all descendants to reflow).
+#define nsChangeHint_ReflowHintsForISizeChange            \
+  nsChangeHint(nsChangeHint_AllReflowHints &              \
+               ~(nsChangeHint_ClearDescendantIntrinsics | \
+                 nsChangeHint_NeedDirtyReflow))
+
+// * For a BSize change, we send almost the same hints as for ISize changes,
+// with one extra: nsChangeHint_UpdateComputedBSize.  We need this hint because
+// BSize changes CAN affect descendant intrinsic sizes, due to replaced
+// elements with percentage BSizes in descendants which also have percentage
+// BSizes. nsChangeHint_UpdateComputedBSize clears intrinsic sizes for frames
+// that have such replaced elements. (We could instead send
+// nsChangeHint_ClearDescendantIntrinsics, but that's broader than we need.)
+//
+// NOTE: You might think that BSize changes could exclude
+// nsChangeHint_ClearAncestorIntrinsics (which is inline-axis specific), but we
+// do need to send it, to clear cached results from CSS Flex measuring reflows.
+#define nsChangeHint_ReflowHintsForBSizeChange                           \
+  nsChangeHint(                                                          \
+      (nsChangeHint_AllReflowHints | nsChangeHint_UpdateComputedBSize) & \
+      ~(nsChangeHint_ClearDescendantIntrinsics |                         \
+        nsChangeHint_NeedDirtyReflow))
+
+// For a change in whether a scrollframe displays or not scrollbars.
+//
+// When requesting this reflow, we send the exact same change hints that "width"
+// and "height" would send (since conceptually, adding/removing scrollbars is
+// like changing the available space).
+//
+// FIXME(emilio): Seems we could be a bit more efficient here, as adding or
+// removing scrollbars doesn't change the size of the element itself, so maybe
+// ClearAncestorIntrinsics or ReflowChangesSizeOrPosition are not needed... I
+// think this ideally should be just nsChangehint_NeedReflow.
+#define nsChangeHint_ReflowHintsForScrollbarChange      \
+  nsChangeHint(nsChangeHint_ReflowHintsForBSizeChange | \
+               nsChangeHint_ReflowHintsForISizeChange)
+
+// * For changes to the float area of an already-floated element, we need all
+// reflow hints, but not the ones that apply to descendants.
+// Our descendants aren't impacted when our float area only changes
+// placement but not size/shape. (e.g. if we change which side we float to).
+// But our ancestors/siblings are potentially impacted, so we need to send
+// the non-descendant reflow hints.
+#define nsChangeHint_ReflowHintsForFloatAreaChange        \
+  nsChangeHint(nsChangeHint_AllReflowHints &              \
+               ~(nsChangeHint_ClearDescendantIntrinsics | \
+                 nsChangeHint_NeedDirtyReflow))
+
+#define NS_STYLE_HINT_REFLOW \
+  nsChangeHint(NS_STYLE_HINT_VISUAL | nsChangeHint_AllReflowHints)
+
+#define nsChangeHint_Hints_CanIgnoreIfNotVisible                            \
+  nsChangeHint(                                                             \
+      NS_STYLE_HINT_VISUAL | nsChangeHint_NeutralChange |                   \
+      nsChangeHint_UpdateOpacityLayer | nsChangeHint_AddOrRemoveTransform | \
+      nsChangeHint_UpdateContainingBlock | nsChangeHint_UpdateOverflow |    \
+      nsChangeHint_UpdatePostTransformOverflow |                            \
+      nsChangeHint_UpdateTransformLayer | nsChangeHint_UpdateUsesOpacity |  \
+      nsChangeHint_UpdateBackgroundPosition | nsChangeHint_VisibilityChange)
+
+// Change hints for added or removed transform style.
+//
+// If we've added or removed the transform property, we need to reconstruct the
+// frame to add or remove the view object, and also to handle abs-pos and
+// fixed-pos containers.
+//
+// We do not need to apply nsChangeHint_UpdateTransformLayer since
+// nsChangeHint_RepaintFrame will forcibly invalidate the frame area and
+// ensure layers are rebuilt (or removed).
+#define nsChangeHint_ComprehensiveAddOrRemoveTransform \
+  nsChangeHint(nsChangeHint_UpdateContainingBlock |    \
+               nsChangeHint_AddOrRemoveTransform |     \
+               nsChangeHint_UpdateOverflow | nsChangeHint_RepaintFrame)
+
+// NB: Once we drop support for the old style system, this logic should be
+// inlined in the Servo style system to eliminate the FFI call.
+inline nsChangeHint NS_HintsNotHandledForDescendantsIn(
+    nsChangeHint aChangeHint) {
+  nsChangeHint result =
+      aChangeHint & nsChangeHint_Hints_NeverHandledForDescendants;
+
+  if (!(aChangeHint & nsChangeHint_NeedDirtyReflow)) {
+    if (aChangeHint & nsChangeHint_NeedReflow) {
+      // If NeedDirtyReflow is *not* set, then NeedReflow is a
+      // non-inherited hint.
+      result |= nsChangeHint_NeedReflow;
+    }
+
+    if (aChangeHint & nsChangeHint_ReflowChangesSizeOrPosition) {
+      // If NeedDirtyReflow is *not* set, then ReflowChangesSizeOrPosition is a
+      // non-inherited hint.
+      result |= nsChangeHint_ReflowChangesSizeOrPosition;
+    }
+  }
+
+  if (!(aChangeHint & nsChangeHint_ClearDescendantIntrinsics) &&
+      (aChangeHint & nsChangeHint_ClearAncestorIntrinsics)) {
+    // If ClearDescendantIntrinsics is *not* set, then
+    // ClearAncestorIntrinsics is a non-inherited hint.
+    result |= nsChangeHint_ClearAncestorIntrinsics;
+  }
+
+  MOZ_ASSERT(
+      NS_IsHintSubset(result, nsChangeHint_Hints_NotHandledForDescendants),
+      "something is inconsistent");
+
+  return result;
+}
+
+inline nsChangeHint NS_HintsHandledForDescendantsIn(nsChangeHint aChangeHint) {
+  return aChangeHint & ~NS_HintsNotHandledForDescendantsIn(aChangeHint);
+}
+
+// Returns the change hints in aOurChange that are not subsumed by those
+// in aHintsHandled (which are hints that have been handled by an ancestor).
+inline nsChangeHint NS_RemoveSubsumedHints(nsChangeHint aOurChange,
+                                           nsChangeHint aHintsHandled) {
+  nsChangeHint result =
+      aOurChange & ~NS_HintsHandledForDescendantsIn(aHintsHandled);
+
+  if (result &
+      (nsChangeHint_ClearAncestorIntrinsics |
+       nsChangeHint_ClearDescendantIntrinsics | nsChangeHint_NeedDirtyReflow |
+       nsChangeHint_ReflowChangesSizeOrPosition |
+       nsChangeHint_UpdateComputedBSize)) {
+    result |= nsChangeHint_NeedReflow;
+  }
+
+  if (result & (nsChangeHint_ClearDescendantIntrinsics)) {
+    MOZ_ASSERT(result & nsChangeHint_ClearAncestorIntrinsics);
+    result |=  // nsChangeHint_ClearAncestorIntrinsics |
+        nsChangeHint_NeedDirtyReflow;
+  }
+
+  return result;
+}
+
+namespace mozilla {
+
+struct StyleRestyleHint;
+
+using RestyleHint = StyleRestyleHint;
+
+}  // namespace mozilla
+
+#endif /* nsChangeHint_h___ */