Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

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

1 files changed, 656 insertions, 0 deletions

diff --git a/servo/components/style/invalidation/stylesheets.rs b/servo/components/style/invalidation/stylesheets.rs
new file mode 100644
index 0000000000..5fc8ec4b76
--- /dev/null
+++ b/servo/components/style/invalidation/stylesheets.rs
@@ -0,0 +1,656 @@
+/* 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/. */
+
+//! A collection of invalidations due to changes in which stylesheets affect a
+//! document.
+
+#![deny(unsafe_code)]
+
+use crate::context::QuirksMode;
+use crate::dom::{TDocument, TElement, TNode};
+use crate::invalidation::element::element_wrapper::{ElementSnapshot, ElementWrapper};
+use crate::invalidation::element::restyle_hints::RestyleHint;
+use crate::media_queries::Device;
+use crate::selector_map::{MaybeCaseInsensitiveHashMap, PrecomputedHashMap};
+use crate::selector_parser::{SelectorImpl, Snapshot, SnapshotMap};
+use crate::shared_lock::SharedRwLockReadGuard;
+use crate::stylesheets::{CssRule, StylesheetInDocument};
+use crate::stylesheets::{EffectiveRules, EffectiveRulesIterator};
+use crate::values::AtomIdent;
+use crate::LocalName as SelectorLocalName;
+use crate::{Atom, ShrinkIfNeeded};
+use selectors::parser::{Component, LocalName, Selector};
+
+/// The kind of change that happened for a given rule.
+#[repr(u32)]
+#[derive(Clone, Copy, Debug, Eq, Hash, MallocSizeOf, PartialEq)]
+pub enum RuleChangeKind {
+    /// The rule was inserted.
+    Insertion,
+    /// The rule was removed.
+    Removal,
+    /// Some change in the rule which we don't know about, and could have made
+    /// the rule change in any way.
+    Generic,
+    /// A change in the declarations of a style rule.
+    StyleRuleDeclarations,
+}
+
+/// A style sheet invalidation represents a kind of element or subtree that may
+/// need to be restyled. Whether it represents a whole subtree or just a single
+/// element is determined by the given InvalidationKind in
+/// StylesheetInvalidationSet's maps.
+#[derive(Debug, Eq, Hash, MallocSizeOf, PartialEq)]
+enum Invalidation {
+    /// An element with a given id.
+    ID(AtomIdent),
+    /// An element with a given class name.
+    Class(AtomIdent),
+    /// An element with a given local name.
+    LocalName {
+        name: SelectorLocalName,
+        lower_name: SelectorLocalName,
+    },
+}
+
+impl Invalidation {
+    fn is_id(&self) -> bool {
+        matches!(*self, Invalidation::ID(..))
+    }
+
+    fn is_id_or_class(&self) -> bool {
+        matches!(*self, Invalidation::ID(..) | Invalidation::Class(..))
+    }
+}
+
+/// Whether we should invalidate just the element, or the whole subtree within
+/// it.
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Ord, PartialEq, PartialOrd)]
+enum InvalidationKind {
+    None = 0,
+    Element,
+    Scope,
+}
+
+impl std::ops::BitOrAssign for InvalidationKind {
+    #[inline]
+    fn bitor_assign(&mut self, other: Self) {
+        *self = std::cmp::max(*self, other);
+    }
+}
+
+impl InvalidationKind {
+    #[inline]
+    fn is_scope(self) -> bool {
+        matches!(self, Self::Scope)
+    }
+
+    #[inline]
+    fn add(&mut self, other: Option<&InvalidationKind>) {
+        if let Some(other) = other {
+            *self |= *other;
+        }
+    }
+}
+
+/// A set of invalidations due to stylesheet additions.
+///
+/// TODO(emilio): We might be able to do the same analysis for media query
+/// changes too (or even selector changes?).
+#[derive(Debug, Default, MallocSizeOf)]
+pub struct StylesheetInvalidationSet {
+    classes: MaybeCaseInsensitiveHashMap<Atom, InvalidationKind>,
+    ids: MaybeCaseInsensitiveHashMap<Atom, InvalidationKind>,
+    local_names: PrecomputedHashMap<SelectorLocalName, InvalidationKind>,
+    fully_invalid: bool,
+}
+
+impl StylesheetInvalidationSet {
+    /// Create an empty `StylesheetInvalidationSet`.
+    pub fn new() -> Self {
+        Default::default()
+    }
+
+    /// Mark the DOM tree styles' as fully invalid.
+    pub fn invalidate_fully(&mut self) {
+        debug!("StylesheetInvalidationSet::invalidate_fully");
+        self.clear();
+        self.fully_invalid = true;
+    }
+
+    fn shrink_if_needed(&mut self) {
+        if self.fully_invalid {
+            return;
+        }
+        self.classes.shrink_if_needed();
+        self.ids.shrink_if_needed();
+        self.local_names.shrink_if_needed();
+    }
+
+    /// Analyze the given stylesheet, and collect invalidations from their
+    /// rules, in order to avoid doing a full restyle when we style the document
+    /// next time.
+    pub fn collect_invalidations_for<S>(
+        &mut self,
+        device: &Device,
+        stylesheet: &S,
+        guard: &SharedRwLockReadGuard,
+    ) where
+        S: StylesheetInDocument,
+    {
+        debug!("StylesheetInvalidationSet::collect_invalidations_for");
+        if self.fully_invalid {
+            debug!(" > Fully invalid already");
+            return;
+        }
+
+        if !stylesheet.enabled() || !stylesheet.is_effective_for_device(device, guard) {
+            debug!(" > Stylesheet was not effective");
+            return; // Nothing to do here.
+        }
+
+        let quirks_mode = device.quirks_mode();
+        for rule in stylesheet.effective_rules(device, guard) {
+            self.collect_invalidations_for_rule(rule, guard, device, quirks_mode);
+            if self.fully_invalid {
+                break;
+            }
+        }
+
+        self.shrink_if_needed();
+
+        debug!(" > resulting class invalidations: {:?}", self.classes);
+        debug!(" > resulting id invalidations: {:?}", self.ids);
+        debug!(
+            " > resulting local name invalidations: {:?}",
+            self.local_names
+        );
+        debug!(" > fully_invalid: {}", self.fully_invalid);
+    }
+
+    /// Clears the invalidation set, invalidating elements as needed if
+    /// `document_element` is provided.
+    ///
+    /// Returns true if any invalidations ocurred.
+    pub fn flush<E>(&mut self, document_element: Option<E>, snapshots: Option<&SnapshotMap>) -> bool
+    where
+        E: TElement,
+    {
+        debug!(
+            "Stylist::flush({:?}, snapshots: {})",
+            document_element,
+            snapshots.is_some()
+        );
+        let have_invalidations = match document_element {
+            Some(e) => self.process_invalidations(e, snapshots),
+            None => false,
+        };
+        self.clear();
+        have_invalidations
+    }
+
+    /// Returns whether there's no invalidation to process.
+    pub fn is_empty(&self) -> bool {
+        !self.fully_invalid &&
+            self.classes.is_empty() &&
+            self.ids.is_empty() &&
+            self.local_names.is_empty()
+    }
+
+    fn invalidation_kind_for<E>(
+        &self,
+        element: E,
+        snapshot: Option<&Snapshot>,
+        quirks_mode: QuirksMode,
+    ) -> InvalidationKind
+    where
+        E: TElement,
+    {
+        debug_assert!(!self.fully_invalid);
+
+        let mut kind = InvalidationKind::None;
+
+        if !self.classes.is_empty() {
+            element.each_class(|c| {
+                kind.add(self.classes.get(c, quirks_mode));
+            });
+
+            if kind.is_scope() {
+                return kind;
+            }
+
+            if let Some(snapshot) = snapshot {
+                snapshot.each_class(|c| {
+                    kind.add(self.classes.get(c, quirks_mode));
+                });
+
+                if kind.is_scope() {
+                    return kind;
+                }
+            }
+        }
+
+        if !self.ids.is_empty() {
+            if let Some(ref id) = element.id() {
+                kind.add(self.ids.get(id, quirks_mode));
+                if kind.is_scope() {
+                    return kind;
+                }
+            }
+
+            if let Some(ref old_id) = snapshot.and_then(|s| s.id_attr()) {
+                kind.add(self.ids.get(old_id, quirks_mode));
+                if kind.is_scope() {
+                    return kind;
+                }
+            }
+        }
+
+        if !self.local_names.is_empty() {
+            kind.add(self.local_names.get(element.local_name()));
+        }
+
+        kind
+    }
+
+    /// Clears the invalidation set without processing.
+    pub fn clear(&mut self) {
+        self.classes.clear();
+        self.ids.clear();
+        self.local_names.clear();
+        self.fully_invalid = false;
+        debug_assert!(self.is_empty());
+    }
+
+    fn process_invalidations<E>(&self, element: E, snapshots: Option<&SnapshotMap>) -> bool
+    where
+        E: TElement,
+    {
+        debug!("Stylist::process_invalidations({:?}, {:?})", element, self);
+
+        {
+            let mut data = match element.mutate_data() {
+                Some(data) => data,
+                None => return false,
+            };
+
+            if self.fully_invalid {
+                debug!("process_invalidations: fully_invalid({:?})", element);
+                data.hint.insert(RestyleHint::restyle_subtree());
+                return true;
+            }
+        }
+
+        if self.is_empty() {
+            debug!("process_invalidations: empty invalidation set");
+            return false;
+        }
+
+        let quirks_mode = element.as_node().owner_doc().quirks_mode();
+        self.process_invalidations_in_subtree(element, snapshots, quirks_mode)
+    }
+
+    /// Process style invalidations in a given subtree. This traverses the
+    /// subtree looking for elements that match the invalidations in our hash
+    /// map members.
+    ///
+    /// Returns whether it invalidated at least one element's style.
+    #[allow(unsafe_code)]
+    fn process_invalidations_in_subtree<E>(
+        &self,
+        element: E,
+        snapshots: Option<&SnapshotMap>,
+        quirks_mode: QuirksMode,
+    ) -> bool
+    where
+        E: TElement,
+    {
+        debug!("process_invalidations_in_subtree({:?})", element);
+        let mut data = match element.mutate_data() {
+            Some(data) => data,
+            None => return false,
+        };
+
+        if !data.has_styles() {
+            return false;
+        }
+
+        if data.hint.contains_subtree() {
+            debug!(
+                "process_invalidations_in_subtree: {:?} was already invalid",
+                element
+            );
+            return false;
+        }
+
+        let element_wrapper = snapshots.map(|s| ElementWrapper::new(element, s));
+        let snapshot = element_wrapper.as_ref().and_then(|e| e.snapshot());
+
+        match self.invalidation_kind_for(element, snapshot, quirks_mode) {
+            InvalidationKind::None => {},
+            InvalidationKind::Element => {
+                debug!(
+                    "process_invalidations_in_subtree: {:?} matched self",
+                    element
+                );
+                data.hint.insert(RestyleHint::RESTYLE_SELF);
+            },
+            InvalidationKind::Scope => {
+                debug!(
+                    "process_invalidations_in_subtree: {:?} matched subtree",
+                    element
+                );
+                data.hint.insert(RestyleHint::restyle_subtree());
+                return true;
+            },
+        }
+
+        let mut any_children_invalid = false;
+
+        for child in element.traversal_children() {
+            let child = match child.as_element() {
+                Some(e) => e,
+                None => continue,
+            };
+
+            any_children_invalid |=
+                self.process_invalidations_in_subtree(child, snapshots, quirks_mode);
+        }
+
+        if any_children_invalid {
+            debug!(
+                "Children of {:?} changed, setting dirty descendants",
+                element
+            );
+            unsafe { element.set_dirty_descendants() }
+        }
+
+        data.hint.contains(RestyleHint::RESTYLE_SELF) || any_children_invalid
+    }
+
+    /// TODO(emilio): Reuse the bucket stuff from selectormap? That handles
+    /// :is() / :where() etc.
+    fn scan_component(
+        component: &Component<SelectorImpl>,
+        invalidation: &mut Option<Invalidation>,
+    ) {
+        match *component {
+            Component::LocalName(LocalName {
+                ref name,
+                ref lower_name,
+            }) => {
+                if invalidation.is_none() {
+                    *invalidation = Some(Invalidation::LocalName {
+                        name: name.clone(),
+                        lower_name: lower_name.clone(),
+                    });
+                }
+            },
+            Component::Class(ref class) => {
+                if invalidation.as_ref().map_or(true, |s| !s.is_id_or_class()) {
+                    *invalidation = Some(Invalidation::Class(class.clone()));
+                }
+            },
+            Component::ID(ref id) => {
+                if invalidation.as_ref().map_or(true, |s| !s.is_id()) {
+                    *invalidation = Some(Invalidation::ID(id.clone()));
+                }
+            },
+            _ => {
+                // Ignore everything else, at least for now.
+            },
+        }
+    }
+
+    /// Collect invalidations for a given selector.
+    ///
+    /// We look at the outermost local name, class, or ID selector to the left
+    /// of an ancestor combinator, in order to restyle only a given subtree.
+    ///
+    /// If the selector has no ancestor combinator, then we do the same for
+    /// the only sequence it has, but record it as an element invalidation
+    /// instead of a subtree invalidation.
+    ///
+    /// We prefer IDs to classs, and classes to local names, on the basis
+    /// that the former should be more specific than the latter. We also
+    /// prefer to generate subtree invalidations for the outermost part
+    /// of the selector, to reduce the amount of traversal we need to do
+    /// when flushing invalidations.
+    fn collect_invalidations(
+        &mut self,
+        selector: &Selector<SelectorImpl>,
+        quirks_mode: QuirksMode,
+    ) {
+        debug!(
+            "StylesheetInvalidationSet::collect_invalidations({:?})",
+            selector
+        );
+
+        let mut element_invalidation: Option<Invalidation> = None;
+        let mut subtree_invalidation: Option<Invalidation> = None;
+
+        let mut scan_for_element_invalidation = true;
+        let mut scan_for_subtree_invalidation = false;
+
+        let mut iter = selector.iter();
+
+        loop {
+            for component in &mut iter {
+                if scan_for_element_invalidation {
+                    Self::scan_component(component, &mut element_invalidation);
+                } else if scan_for_subtree_invalidation {
+                    Self::scan_component(component, &mut subtree_invalidation);
+                }
+            }
+            match iter.next_sequence() {
+                None => break,
+                Some(combinator) => {
+                    scan_for_subtree_invalidation = combinator.is_ancestor();
+                },
+            }
+            scan_for_element_invalidation = false;
+        }
+
+        if let Some(s) = subtree_invalidation {
+            debug!(" > Found subtree invalidation: {:?}", s);
+            if self.insert_invalidation(s, InvalidationKind::Scope, quirks_mode) {
+                return;
+            }
+        }
+
+        if let Some(s) = element_invalidation {
+            debug!(" > Found element invalidation: {:?}", s);
+            if self.insert_invalidation(s, InvalidationKind::Element, quirks_mode) {
+                return;
+            }
+        }
+
+        // The selector was of a form that we can't handle. Any element could
+        // match it, so let's just bail out.
+        debug!(" > Can't handle selector or OOMd, marking fully invalid");
+        self.invalidate_fully()
+    }
+
+    fn insert_invalidation(
+        &mut self,
+        invalidation: Invalidation,
+        kind: InvalidationKind,
+        quirks_mode: QuirksMode,
+    ) -> bool {
+        match invalidation {
+            Invalidation::Class(c) => {
+                let entry = match self.classes.try_entry(c.0, quirks_mode) {
+                    Ok(e) => e,
+                    Err(..) => return false,
+                };
+                *entry.or_insert(InvalidationKind::None) |= kind;
+            },
+            Invalidation::ID(i) => {
+                let entry = match self.ids.try_entry(i.0, quirks_mode) {
+                    Ok(e) => e,
+                    Err(..) => return false,
+                };
+                *entry.or_insert(InvalidationKind::None) |= kind;
+            },
+            Invalidation::LocalName { name, lower_name } => {
+                let insert_lower = name != lower_name;
+                if self.local_names.try_reserve(1).is_err() {
+                    return false;
+                }
+                let entry = self.local_names.entry(name);
+                *entry.or_insert(InvalidationKind::None) |= kind;
+                if insert_lower {
+                    if self.local_names.try_reserve(1).is_err() {
+                        return false;
+                    }
+                    let entry = self.local_names.entry(lower_name);
+                    *entry.or_insert(InvalidationKind::None) |= kind;
+                }
+            },
+        }
+
+        true
+    }
+
+    /// Collects invalidations for a given CSS rule, if not fully invalid
+    /// already.
+    ///
+    /// TODO(emilio): we can't check whether the rule is inside a non-effective
+    /// subtree, we potentially could do that.
+    pub fn rule_changed<S>(
+        &mut self,
+        stylesheet: &S,
+        rule: &CssRule,
+        guard: &SharedRwLockReadGuard,
+        device: &Device,
+        quirks_mode: QuirksMode,
+        change_kind: RuleChangeKind,
+    ) where
+        S: StylesheetInDocument,
+    {
+        use crate::stylesheets::CssRule::*;
+
+        debug!("StylesheetInvalidationSet::rule_changed");
+        if self.fully_invalid {
+            return;
+        }
+
+        if !stylesheet.enabled() || !stylesheet.is_effective_for_device(device, guard) {
+            debug!(" > Stylesheet was not effective");
+            return; // Nothing to do here.
+        }
+
+        let is_generic_change = change_kind == RuleChangeKind::Generic;
+
+        match *rule {
+            Namespace(..) => {
+                // It's not clear what handling changes for this correctly would
+                // look like.
+            },
+            CounterStyle(..) |
+            Page(..) |
+            Property(..) |
+            Viewport(..) |
+            FontFeatureValues(..) |
+            FontPaletteValues(..) |
+            LayerStatement(..) |
+            FontFace(..) |
+            Keyframes(..) |
+            Container(..) |
+            Style(..) => {
+                if is_generic_change {
+                    // TODO(emilio): We need to do this for selector / keyframe
+                    // name / font-face changes, because we don't have the old
+                    // selector / name.  If we distinguish those changes
+                    // specially, then we can at least use this invalidation for
+                    // style declaration changes.
+                    return self.invalidate_fully();
+                }
+
+                self.collect_invalidations_for_rule(rule, guard, device, quirks_mode)
+            },
+            Document(..) | Import(..) | Media(..) | Supports(..) | LayerBlock(..) => {
+                if !is_generic_change &&
+                    !EffectiveRules::is_effective(guard, device, quirks_mode, rule)
+                {
+                    return;
+                }
+
+                let rules =
+                    EffectiveRulesIterator::effective_children(device, quirks_mode, guard, rule);
+                for rule in rules {
+                    self.collect_invalidations_for_rule(rule, guard, device, quirks_mode);
+                    if self.fully_invalid {
+                        break;
+                    }
+                }
+            },
+        }
+    }
+
+    /// Collects invalidations for a given CSS rule.
+    fn collect_invalidations_for_rule(
+        &mut self,
+        rule: &CssRule,
+        guard: &SharedRwLockReadGuard,
+        device: &Device,
+        quirks_mode: QuirksMode,
+    ) {
+        use crate::stylesheets::CssRule::*;
+        debug!("StylesheetInvalidationSet::collect_invalidations_for_rule");
+        debug_assert!(!self.fully_invalid, "Not worth to be here!");
+
+        match *rule {
+            Style(ref lock) => {
+                let style_rule = lock.read_with(guard);
+                for selector in &style_rule.selectors.0 {
+                    self.collect_invalidations(selector, quirks_mode);
+                    if self.fully_invalid {
+                        return;
+                    }
+                }
+            },
+            Document(..) | Namespace(..) | Import(..) | Media(..) | Supports(..) |
+            Container(..) | LayerStatement(..) | LayerBlock(..) => {
+                // Do nothing, relevant nested rules are visited as part of the
+                // iteration.
+            },
+            FontFace(..) => {
+                // Do nothing, @font-face doesn't affect computed style
+                // information. We'll restyle when the font face loads, if
+                // needed.
+            },
+            Keyframes(ref lock) => {
+                let keyframes_rule = lock.read_with(guard);
+                if device.animation_name_may_be_referenced(&keyframes_rule.name) {
+                    debug!(
+                        " > Found @keyframes rule potentially referenced \
+                         from the page, marking the whole tree invalid."
+                    );
+                    self.fully_invalid = true;
+                } else {
+                    // Do nothing, this animation can't affect the style of
+                    // existing elements.
+                }
+            },
+            CounterStyle(..) |
+            Page(..) |
+            Property(..) |
+            Viewport(..) |
+            FontFeatureValues(..) |
+            FontPaletteValues(..) => {
+                debug!(
+                    " > Found unsupported rule, marking the whole subtree \
+                     invalid."
+                );
+
+                // TODO(emilio): Can we do better here?
+                //
+                // At least in `@page`, we could check the relevant media, I
+                // guess.
+                self.fully_invalid = true;
+            },
+        }
+    }
+}