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https://github.com/servo/servo.git
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style: Refactor RestyleHint to be a struct.
Later PRs will add additional data to it that is not so easy to represent using bitflags.
This commit is contained in:
Cameron McCormack
Emilio Cobos Álvarez
parent
c13be5cd13
commit
a397590838
9 changed files with 294 additions and 111 deletions
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@ -28,32 +28,38 @@ use std::cell::Cell;
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use std::clone::Clone;
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use stylist::SelectorMap;
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/// When the ElementState of an element (like IN_HOVER_STATE) changes,
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/// certain pseudo-classes (like :hover) may require us to restyle that
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/// element, its siblings, and/or its descendants. Similarly, when various
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/// attributes of an element change, we may also need to restyle things with
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/// id, class, and attribute selectors. Doing this conservatively is
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/// expensive, and so we use RestyleHints to short-circuit work we know is
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/// unnecessary.
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#[derive(Debug, Clone, PartialEq)]
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pub struct RestyleHint {
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/// Rerun selector matching on the element.
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match_self: bool,
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/// Rerun selector matching on all of the element's descendants.
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match_descendants: bool,
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/// Rerun selector matching on all later siblings of the element and all
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/// of their descendants.
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match_later_siblings: bool,
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/// Levels of the cascade whose rule nodes should be recomputed and
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/// replaced.
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pub replacements: RestyleReplacements,
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}
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bitflags! {
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/// When the ElementState of an element (like IN_HOVER_STATE) changes,
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/// certain pseudo-classes (like :hover) may require us to restyle that
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/// element, its siblings, and/or its descendants. Similarly, when various
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/// attributes of an element change, we may also need to restyle things with
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/// id, class, and attribute selectors. Doing this conservatively is
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/// expensive, and so we use RestyleHints to short-circuit work we know is
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/// unnecessary.
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/// Cascade levels that can be updated for an element by simply replacing
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/// their rule node.
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///
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/// Note that the bit values here must be kept in sync with the Gecko
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/// nsRestyleHint values. If you add more bits with matching values,
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/// please add assertions to assert_restyle_hints_match below.
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pub flags RestyleHint: u32 {
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/// Rerun selector matching on the element.
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const RESTYLE_SELF = 0x01,
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/// Rerun selector matching on all of the element's descendants.
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///
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/// NB: In Gecko, we have RESTYLE_SUBTREE which is inclusive of self,
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/// but heycam isn't aware of a good reason for that.
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const RESTYLE_DESCENDANTS = 0x04,
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/// Rerun selector matching on all later siblings of the element and all
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/// of their descendants.
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const RESTYLE_LATER_SIBLINGS = 0x08,
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pub flags RestyleReplacements: u8 {
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/// Replace the style data coming from CSS transitions without updating
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/// any other style data. This hint is only processed in animation-only
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/// traversal which is prior to normal traversal.
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@ -76,7 +82,7 @@ bitflags! {
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}
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}
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/// Asserts that all RestyleHint flags have a matching nsRestyleHint value.
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/// Asserts that all RestyleReplacements have a matching nsRestyleHint value.
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#[cfg(feature = "gecko")]
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#[inline]
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pub fn assert_restyle_hints_match() {
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@ -85,24 +91,18 @@ pub fn assert_restyle_hints_match() {
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macro_rules! check_restyle_hints {
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( $( $a:ident => $b:ident ),*, ) => {
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if cfg!(debug_assertions) {
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let mut hints = RestyleHint::all();
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let mut replacements = RestyleReplacements::all();
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$(
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assert_eq!(structs::$a.0 as usize, $b.bits() as usize, stringify!($b));
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hints.remove($b);
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replacements.remove($b);
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)*
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assert_eq!(hints, RestyleHint::empty(), "all RestyleHint bits should have an assertion");
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assert_eq!(replacements, RestyleReplacements::empty(),
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"all RestyleReplacements bits should have an assertion");
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}
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}
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}
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check_restyle_hints! {
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nsRestyleHint_eRestyle_Self => RESTYLE_SELF,
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// Note that eRestyle_Subtree means "self and descendants", while
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// RESTYLE_DESCENDANTS means descendants only. The From impl
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// below handles converting eRestyle_Subtree into
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// (RESTYLE_SELF | RESTYLE_DESCENDANTS).
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nsRestyleHint_eRestyle_Subtree => RESTYLE_DESCENDANTS,
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nsRestyleHint_eRestyle_LaterSiblings => RESTYLE_LATER_SIBLINGS,
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nsRestyleHint_eRestyle_CSSTransitions => RESTYLE_CSS_TRANSITIONS,
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nsRestyleHint_eRestyle_CSSAnimations => RESTYLE_CSS_ANIMATIONS,
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nsRestyleHint_eRestyle_StyleAttribute => RESTYLE_STYLE_ATTRIBUTE,
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@ -111,39 +111,220 @@ pub fn assert_restyle_hints_match() {
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}
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impl RestyleHint {
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/// The subset hints that affect the styling of a single element during the
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/// traversal.
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/// Creates a new, empty `RestyleHint`, which represents no restyling work
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/// needs to be done.
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#[inline]
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pub fn for_self() -> Self {
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RESTYLE_SELF | RESTYLE_STYLE_ATTRIBUTE | Self::for_animations()
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pub fn empty() -> Self {
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RestyleHint {
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match_self: false,
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match_descendants: false,
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match_later_siblings: false,
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replacements: RestyleReplacements::empty(),
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}
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}
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/// The subset hints that are used for animation restyle.
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/// Creates a new `RestyleHint` that indicates selector matching must be
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/// re-run on the element.
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#[inline]
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pub fn for_self() -> Self {
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RestyleHint {
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match_self: true,
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match_descendants: false,
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match_later_siblings: false,
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replacements: RestyleReplacements::empty(),
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}
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}
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/// Creates a new `RestyleHint` that indicates selector matching must be
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/// re-run on all of the element's descendants.
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#[inline]
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pub fn descendants() -> Self {
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RestyleHint {
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match_self: false,
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match_descendants: true,
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match_later_siblings: false,
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replacements: RestyleReplacements::empty(),
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}
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}
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/// Creates a new `RestyleHint` that indicates selector matching must be
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/// re-run on all of the element's later siblings and their descendants.
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#[inline]
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pub fn later_siblings() -> Self {
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RestyleHint {
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match_self: false,
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match_descendants: false,
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match_later_siblings: true,
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replacements: RestyleReplacements::empty(),
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}
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}
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/// Creates a new `RestyleHint` that indicates selector matching must be
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/// re-run on the element and all of its descendants.
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#[inline]
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pub fn subtree() -> Self {
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RestyleHint {
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match_self: true,
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match_descendants: true,
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match_later_siblings: false,
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replacements: RestyleReplacements::empty(),
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}
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}
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/// Creates a new `RestyleHint` that indicates selector matching must be
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/// re-run on the element, its descendants, its later siblings, and
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/// their descendants.
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#[inline]
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pub fn subtree_and_later_siblings() -> Self {
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RestyleHint {
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match_self: true,
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match_descendants: true,
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match_later_siblings: true,
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replacements: RestyleReplacements::empty(),
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}
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}
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/// Creates a new `RestyleHint` that indicates the specified rule node
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/// replacements must be performed on the element.
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#[inline]
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pub fn for_replacements(replacements: RestyleReplacements) -> Self {
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RestyleHint {
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match_self: false,
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match_descendants: false,
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match_later_siblings: false,
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replacements: replacements,
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}
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}
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/// Returns whether this `RestyleHint` represents no needed restyle work.
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#[inline]
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pub fn is_empty(&self) -> bool {
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*self == RestyleHint::empty()
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}
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/// Returns whether this `RestyleHint` represents the maximum possible
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/// restyle work, and thus any `insert()` calls will have no effect.
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#[inline]
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pub fn is_maximum(&self) -> bool {
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self.match_self && self.match_descendants && self.match_later_siblings && self.replacements.is_all()
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}
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/// Returns whether the hint specifies that some work must be performed on
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/// the current element.
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#[inline]
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pub fn affects_self(&self) -> bool {
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self.match_self || !self.replacements.is_empty()
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}
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/// Returns whether the hint specifies that later siblings must be restyled.
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#[inline]
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pub fn affects_later_siblings(&self) -> bool {
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self.match_later_siblings
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}
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/// Returns whether the hint specifies that an animation cascade level must
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/// be replaced.
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#[inline]
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pub fn has_animation_hint(&self) -> bool {
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self.replacements.intersects(RestyleReplacements::for_animations())
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}
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/// Returns whether the hint specifies some restyle work other than an
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/// animation cascade level replacement.
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#[inline]
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pub fn has_non_animation_hint(&self) -> bool {
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self.match_self || self.match_descendants || self.match_later_siblings ||
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self.replacements.contains(RESTYLE_STYLE_ATTRIBUTE)
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}
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/// Returns whether the hint specifies that selector matching must be re-run
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/// for the element.
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#[inline]
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pub fn match_self(&self) -> bool {
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self.match_self
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}
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/// Returns a new `RestyleHint` appropriate for children of the current
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/// element.
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#[inline]
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pub fn propagate_for_non_animation_restyle(&self) -> Self {
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if self.match_descendants {
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Self::subtree()
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} else {
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Self::empty()
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}
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}
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/// Removes all of the animation-related hints.
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#[inline]
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pub fn remove_animation_hints(&mut self) {
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self.replacements.remove(RestyleReplacements::for_animations());
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}
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/// Removes the later siblings hint, and returns whether it was present.
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pub fn remove_later_siblings_hint(&mut self) -> bool {
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let later_siblings = self.match_later_siblings;
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self.match_later_siblings = false;
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later_siblings
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}
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/// Unions the specified `RestyleHint` into this one.
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#[inline]
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pub fn insert_from(&mut self, other: &Self) {
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self.match_self |= other.match_self;
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self.match_descendants |= other.match_descendants;
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self.match_later_siblings |= other.match_later_siblings;
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self.replacements.insert(other.replacements);
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}
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/// Unions the specified `RestyleHint` into this one.
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#[inline]
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pub fn insert(&mut self, other: Self) {
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// A later patch should make it worthwhile to have an insert() function
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// that consumes its argument.
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self.insert_from(&other)
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}
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/// Returns whether this `RestyleHint` represents at least as much restyle
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/// work as the specified one.
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#[inline]
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pub fn contains(&mut self, other: &Self) -> bool {
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!(other.match_self && !self.match_self) &&
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!(other.match_descendants && !self.match_descendants) &&
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!(other.match_later_siblings && !self.match_later_siblings) &&
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self.replacements.contains(other.replacements)
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}
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}
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impl RestyleReplacements {
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/// The replacements for the animation cascade levels.
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#[inline]
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pub fn for_animations() -> Self {
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RESTYLE_SMIL | RESTYLE_CSS_ANIMATIONS | RESTYLE_CSS_TRANSITIONS
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}
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}
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#[cfg(feature = "gecko")]
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impl From<nsRestyleHint> for RestyleReplacements {
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fn from(raw: nsRestyleHint) -> Self {
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Self::from_bits_truncate(raw.0 as u8)
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}
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}
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#[cfg(feature = "gecko")]
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impl From<nsRestyleHint> for RestyleHint {
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fn from(raw: nsRestyleHint) -> Self {
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let raw_bits: u32 = raw.0;
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use gecko_bindings::structs::nsRestyleHint_eRestyle_LaterSiblings as eRestyle_LaterSiblings;
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use gecko_bindings::structs::nsRestyleHint_eRestyle_Self as eRestyle_Self;
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use gecko_bindings::structs::nsRestyleHint_eRestyle_SomeDescendants as eRestyle_SomeDescendants;
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use gecko_bindings::structs::nsRestyleHint_eRestyle_Subtree as eRestyle_Subtree;
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// FIXME(bholley): Finish aligning the binary representations here and
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// then .expect() the result of the checked version.
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if Self::from_bits(raw_bits).is_none() {
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warn!("stylo: dropping unsupported restyle hint bits");
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RestyleHint {
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match_self: (raw.0 & (eRestyle_Self.0 | eRestyle_Subtree.0)) != 0,
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match_descendants: (raw.0 & (eRestyle_Subtree.0 | eRestyle_SomeDescendants.0)) != 0,
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match_later_siblings: (raw.0 & eRestyle_LaterSiblings.0) != 0,
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replacements: raw.into(),
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}
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let mut bits = Self::from_bits_truncate(raw_bits);
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// eRestyle_Subtree converts to (RESTYLE_SELF | RESTYLE_DESCENDANTS).
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if bits.contains(RESTYLE_DESCENDANTS) {
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bits |= RESTYLE_SELF;
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}
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bits
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}
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}
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@ -437,15 +618,16 @@ fn is_attr_selector(sel: &Component<SelectorImpl>) -> bool {
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fn combinator_to_restyle_hint(combinator: Option<Combinator>) -> RestyleHint {
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match combinator {
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None => RESTYLE_SELF,
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None => RestyleHint::for_self(),
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Some(c) => match c {
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// NB: RESTYLE_SELF is needed to handle properly eager pseudos,
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// otherwise we may leave a stale style on the parent.
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Combinator::PseudoElement => RESTYLE_SELF | RESTYLE_DESCENDANTS,
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Combinator::Child => RESTYLE_DESCENDANTS,
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Combinator::Descendant => RESTYLE_DESCENDANTS,
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Combinator::NextSibling => RESTYLE_LATER_SIBLINGS,
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Combinator::LaterSibling => RESTYLE_LATER_SIBLINGS,
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// NB: RestyleHint::subtree() and not RestyleHint::descendants() is
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// needed to handle properly eager pseudos, otherwise we may leave
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// a stale style on the parent.
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Combinator::PseudoElement => RestyleHint::subtree(),
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Combinator::Child => RestyleHint::descendants(),
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Combinator::Descendant => RestyleHint::descendants(),
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Combinator::NextSibling => RestyleHint::later_siblings(),
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Combinator::LaterSibling => RestyleHint::later_siblings(),
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}
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}
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}
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@ -700,12 +882,12 @@ impl DependencySet {
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return true;
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}
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if hint.contains(dep.hint) {
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if hint.contains(&dep.hint) {
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trace!(" > hint was already there");
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return true;
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}
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// We can ignore the selector flags, since they would have already
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// We can ignore the selector replacements, since they would have already
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// been set during original matching for any element that might
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// change its matching behavior here.
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let matched_then =
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@ -717,10 +899,10 @@ impl DependencySet {
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&mut matching_context,
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&mut |_, _| {});
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if matched_then != matches_now {
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hint.insert(dep.hint);
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hint.insert_from(&dep.hint);
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}
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!hint.is_all()
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!hint.is_maximum()
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});
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debug!("Calculated restyle hint: {:?} for {:?}. (State={:?}, {} Deps)",
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