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gecko-dev/layout/base/nsChangeHint.h

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/* -*- 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/. */
/* constants for what needs to be recomputed in response to style changes */
#ifndef nsChangeHint_h___
#define nsChangeHint_h___
#include "mozilla/Types.h"
#include "nsDebug.h"
#include "nsTArray.h"
struct nsCSSSelector;
// 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,
// change requires view to be updated, if there is one (e.g., clip:).
// Updates all descendants (including following placeholders to out-of-flows).
nsChangeHint_SyncFrameView = 1 << 5,
// The currently shown mouse cursor needs to be updated
nsChangeHint_UpdateCursor = 1 << 6,
/**
* 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 nsSVGEffects::UpdateEffects being called on the element's
* frame.
*/
nsChangeHint_UpdateEffects = 1 << 7,
/**
* 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 << 8,
/**
* Updates all descendants. Any placeholder descendants' out-of-flows
* are also descendants of the transformed frame, so they're updated.
*/
nsChangeHint_UpdateTransformLayer = 1 << 9,
/**
* 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 << 10,
/**
* The frame's overflow area has changed. Does not update any descendant
* frames.
*/
nsChangeHint_UpdateOverflow = 1 << 11,
/**
* The overflow area of the frame and all of its descendants has changed. This
* can happen through a text-decoration change.
*/
nsChangeHint_UpdateSubtreeOverflow = 1 << 12,
/**
* 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 << 13,
/**
* 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 << 14,
/**
* The children-only transform of an SVG frame changed, requiring the
* overflow rects of the frame's immediate children to be updated.
*/
nsChangeHint_ChildrenOnlyTransform = 1 << 15,
/**
* 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 << 16,
/**
* 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 nsStyleContext::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 << 17,
/**
* 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 << 18,
/**
* SVG textPath needs to be recomputed because the path has changed.
* This means that the glyph positions of the text need to be recomputed.
*/
nsChangeHint_UpdateTextPath = 1 << 19,
/**
* This will schedule an invalidating paint. This is useful if something
* has changed which will be invalidated by DLBI.
*/
nsChangeHint_SchedulePaint = 1 << 20,
/**
* 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 context 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 << 21,
/**
* This will cause rendering observers to be invalidated.
*/
nsChangeHint_InvalidateRenderingObservers = 1 << 22,
/**
* 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 nsChangeHint_ClearAncestorIntrinsics.
*/
nsChangeHint_ReflowChangesSizeOrPosition = 1 << 23,
/**
* Indicates that the style changes the computed BSize --- e.g. 'height'.
* Must not be set without also setting nsChangeHint_NeedReflow.
*/
nsChangeHint_UpdateComputedBSize = 1 << 24,
/**
* 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 << 25,
/**
* 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 << 26,
/**
* Indicates that a frame has changed to or from having the CSS
* transform property set.
*/
nsChangeHint_AddOrRemoveTransform = 1 << 27,
// 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 = (1 << 28) - 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_SyncFrameView | \
nsChangeHint_UpdateCursor | \
nsChangeHint_UpdateSubtreeOverflow | \
nsChangeHint_UpdateTextPath \
)
// The change hints that are never handled for descendants.
#define nsChangeHint_Hints_NeverHandledForDescendants ( \
nsChangeHint_BorderStyleNoneChange | \
nsChangeHint_ChildrenOnlyTransform | \
nsChangeHint_InvalidateRenderingObservers | \
nsChangeHint_RecomputePosition | \
nsChangeHint_UpdateBackgroundPosition | \
nsChangeHint_UpdateComputedBSize | \
nsChangeHint_UpdateContainingBlock | \
nsChangeHint_UpdateEffects | \
nsChangeHint_UpdateOpacityLayer | \
nsChangeHint_UpdateOverflow | \
nsChangeHint_UpdateParentOverflow | \
nsChangeHint_UpdatePostTransformOverflow | \
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_SyncFrameView | \
nsChangeHint_SchedulePaint)
#define nsChangeHint_AllReflowHints \
nsChangeHint(nsChangeHint_NeedReflow | \
nsChangeHint_ReflowChangesSizeOrPosition|\
nsChangeHint_ClearAncestorIntrinsics | \
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_UpdateTransformLayer | \
nsChangeHint_UpdateUsesOpacity)
// 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;
}
/**
* |nsRestyleHint| is a bitfield for the result of
* |HasStateDependentStyle| and |HasAttributeDependentStyle|. When no
* restyling is necessary, use |nsRestyleHint(0)|.
*
* Without eRestyle_Force or eRestyle_ForceDescendants, the restyling process
* can stop processing at a frame when it detects no style changes and it is
* known that the styles of the subtree beneath it will not change, leaving
* the old style context on the frame. eRestyle_Force can be used to skip this
* optimization on a frame, and to force its new style context to be used.
*
* Similarly, eRestyle_ForceDescendants will cause the frame and all of its
* descendants to be traversed and for the new style contexts that are created
* to be set on the frames.
*
* NOTE: When adding new restyle hints, please also add them to
* RestyleManager::RestyleHintToString.
*/
enum nsRestyleHint : uint32_t {
// Rerun selector matching on the element. If a new style context
// results, update the style contexts of descendants. (Irrelevant if
// eRestyle_Subtree is also set, since that implies a superset of the
// work.)
eRestyle_Self = 1 << 0,
// Rerun selector matching on descendants of the element that match
// a given selector.
eRestyle_SomeDescendants = 1 << 1,
// Rerun selector matching on the element and all of its descendants.
// (Implies eRestyle_ForceDescendants, which ensures that we continue
// the restyling process for all descendants, but doesn't cause
// selector matching.)
eRestyle_Subtree = 1 << 2,
// Rerun selector matching on all later siblings of the element and
// all of their descendants.
eRestyle_LaterSiblings = 1 << 3,
// Replace the style data coming from CSS transitions without updating
// any other style data. If a new style context results, update style
// contexts on the descendants. (Irrelevant if eRestyle_Self or
// eRestyle_Subtree is also set, since those imply a superset of the
// work.)
eRestyle_CSSTransitions = 1 << 4,
// Replace the style data coming from CSS animations without updating
// any other style data. If a new style context results, update style
// contexts on the descendants. (Irrelevant if eRestyle_Self or
// eRestyle_Subtree is also set, since those imply a superset of the
// work.)
eRestyle_CSSAnimations = 1 << 5,
// Replace the style data coming from inline style without updating
// any other style data. If a new style context results, update style
// contexts on the descendants. (Irrelevant if eRestyle_Self or
// eRestyle_Subtree is also set, since those imply a superset of the
// work.) Supported only for element style contexts and not for
// pseudo-elements or anonymous boxes, on which it converts to
// eRestyle_Self.
// If the change is for the advance of a declarative animation, use
// the value below instead.
eRestyle_StyleAttribute = 1 << 6,
// Same as eRestyle_StyleAttribute, but for when the change results
// from the advance of a declarative animation.
eRestyle_StyleAttribute_Animations = 1 << 7,
// Continue the restyling process to the current frame's children even
// if this frame's restyling resulted in no style changes.
eRestyle_Force = 1 << 8,
// Continue the restyling process to all of the current frame's
// descendants, even if any frame's restyling resulted in no style
// changes. (Implies eRestyle_Force.) Note that this is weaker than
// eRestyle_Subtree, which makes us rerun selector matching on all
// descendants rather than just continuing the restyling process.
eRestyle_ForceDescendants = 1 << 9,
// Useful unions:
eRestyle_AllHintsWithAnimations = eRestyle_CSSTransitions |
eRestyle_CSSAnimations |
eRestyle_StyleAttribute_Animations,
};
// The functions below need an integral type to cast to to avoid
// infinite recursion.
typedef decltype(nsRestyleHint(0) + nsRestyleHint(0)) nsRestyleHint_size_t;
inline constexpr nsRestyleHint operator|(nsRestyleHint aLeft,
nsRestyleHint aRight)
{
return nsRestyleHint(nsRestyleHint_size_t(aLeft) |
nsRestyleHint_size_t(aRight));
}
inline constexpr nsRestyleHint operator&(nsRestyleHint aLeft,
nsRestyleHint aRight)
{
return nsRestyleHint(nsRestyleHint_size_t(aLeft) &
nsRestyleHint_size_t(aRight));
}
inline nsRestyleHint& operator|=(nsRestyleHint& aLeft, nsRestyleHint aRight)
{
return aLeft = aLeft | aRight;
}
inline nsRestyleHint& operator&=(nsRestyleHint& aLeft, nsRestyleHint aRight)
{
return aLeft = aLeft & aRight;
}
inline constexpr nsRestyleHint operator~(nsRestyleHint aArg)
{
return nsRestyleHint(~nsRestyleHint_size_t(aArg));
}
inline constexpr nsRestyleHint operator^(nsRestyleHint aLeft,
nsRestyleHint aRight)
{
return nsRestyleHint(nsRestyleHint_size_t(aLeft) ^
nsRestyleHint_size_t(aRight));
}
inline nsRestyleHint operator^=(nsRestyleHint& aLeft, nsRestyleHint aRight)
{
return aLeft = aLeft ^ aRight;
}
namespace mozilla {
/**
* Additional data used in conjunction with an nsRestyleHint to control the
* restyle process.
*/
struct RestyleHintData
{
// When eRestyle_SomeDescendants is used, this array contains the selectors
// that identify which descendants will be restyled.
nsTArray<nsCSSSelector*> mSelectorsForDescendants;
};
} // namespace mozilla
#endif /* nsChangeHint_h___ */
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