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/* 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 https://mozilla.org/MPL/2.0/. */
//! Misc information about a given computed style.
/// Misc information about a given computed style.
///
/// All flags are currently inherited for text, pseudo elements, and
/// anonymous boxes, see StyleBuilder::for_inheritance and its callsites.
/// If we ever want to add some flags that shouldn't inherit for them,
/// we might want to add a function to handle this.
#[repr(C)]
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
#[cfg_attr(feature = "servo", derive(crate::derives::MallocSizeOf))]
pub struct ComputedValueFlags(u32);
bitflags! {
impl ComputedValueFlags: u32 {
/// Whether the style or any of the ancestors has a text-decoration-line
/// property that should get propagated to descendants.
///
/// text-decoration-line is a reset property, but gets propagated in the
/// frame/box tree.
const HAS_TEXT_DECORATION_LINES = 1 << 0;
/// Whether line break inside should be suppressed.
///
/// If this flag is set, the line should not be broken inside,
/// which means inlines act as if nowrap is set, <br> element is
/// suppressed, and blocks are inlinized.
///
/// This bit is propagated to all children of line participants.
/// It is currently used by ruby to make its content unbreakable.
const SHOULD_SUPPRESS_LINEBREAK = 1 << 1;
/// A flag used to mark text that that has text-combine-upright.
///
/// This is used from Gecko's layout engine.
const IS_TEXT_COMBINED = 1 << 2;
/// A flag used to mark styles under a relevant link that is also
/// visited.
const IS_RELEVANT_LINK_VISITED = 1 << 3;
/// A flag used to mark styles which are a ::first-line or under one.
const IS_IN_FIRST_LINE_SUBTREE = 1 << 4;
/// A flag used to mark styles which have contain:style or under one.
const SELF_OR_ANCESTOR_HAS_CONTAIN_STYLE = 1 << 5;
/// Whether this style's `display` or `content`property depends on our parent style.
///
/// This is important because it may affect our optimizations to avoid
/// computing the style of pseudo-elements, given whether the
/// pseudo-element is generated depends on the `display` (or `content`) value.
const DISPLAY_OR_CONTENT_DEPEND_ON_INHERITED_STYLE = 1 << 6;
/// Whether the child explicitly inherits any reset property.
const INHERITS_RESET_STYLE = 1 << 7;
/// Whether any value on our style is font-metric-dependent on our
/// primary font.
const DEPENDS_ON_SELF_FONT_METRICS = 1 << 8;
/// Whether any value on our style is font-metric-dependent on the
/// primary font of our parent.
const DEPENDS_ON_INHERITED_FONT_METRICS = 1 << 9;
/// Whether this style is the style of the document element.
const IS_ROOT_ELEMENT_STYLE = 1 << 10;
/// Whether this element is inside an `opacity: 0` subtree.
const IS_IN_OPACITY_ZERO_SUBTREE = 1 << 11;
/// Whether there are author-specified rules for border-* properties
/// (except border-image-*), background-color, or background-image.
///
/// TODO(emilio): Maybe do include border-image, see:
///
/// https://github.com/w3c/csswg-drafts/issues/4777#issuecomment-604424845
const HAS_AUTHOR_SPECIFIED_BORDER_BACKGROUND = 1 << 12;
/// Whether the style depends on viewport units.
const USES_VIEWPORT_UNITS = 1 << 13;
/// Whether the style depends on viewport units on container queries.
///
/// This needs to be a separate flag from `USES_VIEWPORT_UNITS` because
/// it causes us to re-match the style (rather than re-cascascading it,
/// which is enough for other uses of viewport units).
const USES_VIEWPORT_UNITS_ON_CONTAINER_QUERIES = 1 << 14;
/// A flag used to mark styles which have `container-type` of `size` or
/// `inline-size`, or under one.
const SELF_OR_ANCESTOR_HAS_SIZE_CONTAINER_TYPE = 1 << 15;
/// Whether the style uses container query units, in which case the style depends on the
/// container's size and we can't reuse it across cousins (without double-checking the
/// container at least).
const USES_CONTAINER_UNITS = 1 << 16;
/// Whether there are author-specific rules for text `color`.
const HAS_AUTHOR_SPECIFIED_TEXT_COLOR = 1 << 17;
/// Whether this style considered a scope style rule.
const CONSIDERED_NONTRIVIAL_SCOPED_STYLE = 1 << 18;
/// Whether this style is that of a `display: contents` element that is either a direct
/// child of an item container or another `display: contents` element, the style of which
/// has this flag set, marked in order to cascade beyond them to the descendants of the
/// the item container that do generate a box.
const DISPLAY_CONTENTS_IN_ITEM_CONTAINER = 1 << 19;
/// Whether there are author-specific rules for `text-shadow`.
const HAS_AUTHOR_SPECIFIED_TEXT_SHADOW = 1 << 20;
/// Whether this style depends on container style query.
const DEPENDS_ON_CONTAINER_STYLE_QUERY = 1 << 21;
/// Whether this style is in an appearance: base subtree
const IS_IN_APPEARANCE_BASE_SUBTREE = 1 << 22;
/// Whether grid-auto-flow is author-specified.
const HAS_AUTHOR_SPECIFIED_GRID_AUTO_FLOW = 1 << 23;
/// Whether this style depends on root font metrics in container queries.
const DEPENDS_ON_FONT_METRICS_IN_CONTAINER_QUERY = 1 << 24;
}
}
impl Default for ComputedValueFlags {
#[inline]
fn default() -> Self {
Self::empty()
}
}
impl ComputedValueFlags {
/// Flags that are unconditionally propagated to descendants.
#[inline]
fn inherited_flags() -> Self {
Self::IS_RELEVANT_LINK_VISITED
| Self::IS_IN_FIRST_LINE_SUBTREE
| Self::HAS_TEXT_DECORATION_LINES
| Self::IS_IN_OPACITY_ZERO_SUBTREE
| Self::SELF_OR_ANCESTOR_HAS_CONTAIN_STYLE
| Self::SELF_OR_ANCESTOR_HAS_SIZE_CONTAINER_TYPE
| Self::IS_IN_APPEARANCE_BASE_SUBTREE
}
/// Flags that may be propagated to descendants.
#[inline]
fn maybe_inherited_flags() -> Self {
Self::inherited_flags()
| Self::SHOULD_SUPPRESS_LINEBREAK
| Self::DISPLAY_CONTENTS_IN_ITEM_CONTAINER
}
/// Flags that are an input to the cascade.
#[inline]
fn cascade_input_flags() -> Self {
Self::USES_VIEWPORT_UNITS_ON_CONTAINER_QUERIES
| Self::CONSIDERED_NONTRIVIAL_SCOPED_STYLE
| Self::DEPENDS_ON_CONTAINER_STYLE_QUERY
| Self::DEPENDS_ON_FONT_METRICS_IN_CONTAINER_QUERY
}
/// Returns the flags that are always propagated to descendants.
///
/// See StyleAdjuster::set_bits and StyleBuilder.
#[inline]
pub fn inherited(self) -> Self {
self & Self::inherited_flags()
}
/// Flags that are conditionally propagated to descendants, just to handle
/// properly style invalidation.
#[inline]
pub fn maybe_inherited(self) -> Self {
self & Self::maybe_inherited_flags()
}
/// Flags that are an input to the cascade.
#[inline]
pub fn for_cascade_inputs(self) -> Self {
self & Self::cascade_input_flags()
}
}