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/* -*- 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_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 (!NS_IsHintSubset(nsChangeHint_NeedDirtyReflow, aChangeHint)) {
if (NS_IsHintSubset(nsChangeHint_NeedReflow, aChangeHint)) {
// If NeedDirtyReflow is *not* set, then NeedReflow is a
// non-inherited hint.
result |= nsChangeHint_NeedReflow;
}
if (NS_IsHintSubset(nsChangeHint_ReflowChangesSizeOrPosition,
aChangeHint)) {
// If NeedDirtyReflow is *not* set, then ReflowChangesSizeOrPosition is a
// non-inherited hint.
result |= nsChangeHint_ReflowChangesSizeOrPosition;
}
}
if (!NS_IsHintSubset(nsChangeHint_ClearDescendantIntrinsics, aChangeHint) &&
NS_IsHintSubset(nsChangeHint_ClearAncestorIntrinsics, aChangeHint)) {
// 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___ */