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Diffstat (limited to 'servo/components/style/stylesheet_set.rs')
| -rw-r--r-- | servo/components/style/stylesheet_set.rs | 705 |
1 files changed, 705 insertions, 0 deletions
diff --git a/servo/components/style/stylesheet_set.rs b/servo/components/style/stylesheet_set.rs new file mode 100644 index 0000000000..b93bbfe2fd --- /dev/null +++ b/servo/components/style/stylesheet_set.rs @@ -0,0 +1,705 @@ +/* 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 centralized set of stylesheets for a document. + +use crate::dom::TElement; +use crate::invalidation::stylesheets::{RuleChangeKind, StylesheetInvalidationSet}; +use crate::media_queries::Device; +use crate::selector_parser::SnapshotMap; +use crate::shared_lock::SharedRwLockReadGuard; +use crate::stylesheets::{ + CssRule, Origin, OriginSet, OriginSetIterator, PerOrigin, StylesheetInDocument, +}; +use std::{mem, slice}; + +/// Entry for a StylesheetSet. +#[derive(MallocSizeOf)] +struct StylesheetSetEntry<S> +where + S: StylesheetInDocument + PartialEq + 'static, +{ + /// The sheet. + sheet: S, + + /// Whether this sheet has been part of at least one flush. + committed: bool, +} + +impl<S> StylesheetSetEntry<S> +where + S: StylesheetInDocument + PartialEq + 'static, +{ + fn new(sheet: S) -> Self { + Self { + sheet, + committed: false, + } + } +} + +/// A iterator over the stylesheets of a list of entries in the StylesheetSet. +pub struct StylesheetCollectionIterator<'a, S>(slice::Iter<'a, StylesheetSetEntry<S>>) +where + S: StylesheetInDocument + PartialEq + 'static; + +impl<'a, S> Clone for StylesheetCollectionIterator<'a, S> +where + S: StylesheetInDocument + PartialEq + 'static, +{ + fn clone(&self) -> Self { + StylesheetCollectionIterator(self.0.clone()) + } +} + +impl<'a, S> Iterator for StylesheetCollectionIterator<'a, S> +where + S: StylesheetInDocument + PartialEq + 'static, +{ + type Item = &'a S; + + fn next(&mut self) -> Option<Self::Item> { + self.0.next().map(|entry| &entry.sheet) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + self.0.size_hint() + } +} + +/// An iterator over the flattened view of the stylesheet collections. +#[derive(Clone)] +pub struct StylesheetIterator<'a, S> +where + S: StylesheetInDocument + PartialEq + 'static, +{ + origins: OriginSetIterator, + collections: &'a PerOrigin<SheetCollection<S>>, + current: Option<(Origin, StylesheetCollectionIterator<'a, S>)>, +} + +impl<'a, S> Iterator for StylesheetIterator<'a, S> +where + S: StylesheetInDocument + PartialEq + 'static, +{ + type Item = (&'a S, Origin); + + fn next(&mut self) -> Option<Self::Item> { + loop { + if self.current.is_none() { + let next_origin = self.origins.next()?; + + self.current = Some(( + next_origin, + self.collections.borrow_for_origin(&next_origin).iter(), + )); + } + + { + let (origin, ref mut iter) = *self.current.as_mut().unwrap(); + if let Some(s) = iter.next() { + return Some((s, origin)); + } + } + + self.current = None; + } + } +} + +/// The validity of the data in a given cascade origin. +#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Ord, PartialEq, PartialOrd)] +pub enum DataValidity { + /// The origin is clean, all the data already there is valid, though we may + /// have new sheets at the end. + Valid = 0, + + /// The cascade data is invalid, but not the invalidation data (which is + /// order-independent), and thus only the cascade data should be inserted. + CascadeInvalid = 1, + + /// Everything needs to be rebuilt. + FullyInvalid = 2, +} + +impl Default for DataValidity { + fn default() -> Self { + DataValidity::Valid + } +} + +/// A struct to iterate over the different stylesheets to be flushed. +pub struct DocumentStylesheetFlusher<'a, S> +where + S: StylesheetInDocument + PartialEq + 'static, +{ + collections: &'a mut PerOrigin<SheetCollection<S>>, + had_invalidations: bool, +} + +/// The type of rebuild that we need to do for a given stylesheet. +#[derive(Clone, Copy, Debug)] +pub enum SheetRebuildKind { + /// A full rebuild, of both cascade data and invalidation data. + Full, + /// A partial rebuild, of only the cascade data. + CascadeOnly, +} + +impl SheetRebuildKind { + /// Whether the stylesheet invalidation data should be rebuilt. + pub fn should_rebuild_invalidation(&self) -> bool { + matches!(*self, SheetRebuildKind::Full) + } +} + +impl<'a, S> DocumentStylesheetFlusher<'a, S> +where + S: StylesheetInDocument + PartialEq + 'static, +{ + /// Returns a flusher for `origin`. + pub fn flush_origin(&mut self, origin: Origin) -> SheetCollectionFlusher<S> { + self.collections.borrow_mut_for_origin(&origin).flush() + } + + /// Returns the list of stylesheets for `origin`. + /// + /// Only used for UA sheets. + pub fn origin_sheets(&mut self, origin: Origin) -> StylesheetCollectionIterator<S> { + self.collections.borrow_mut_for_origin(&origin).iter() + } + + /// Returns whether any DOM invalidations were processed as a result of the + /// stylesheet flush. + #[inline] + pub fn had_invalidations(&self) -> bool { + self.had_invalidations + } +} + +/// A flusher struct for a given collection, that takes care of returning the +/// appropriate stylesheets that need work. +pub struct SheetCollectionFlusher<'a, S> +where + S: StylesheetInDocument + PartialEq + 'static, +{ + // TODO: This can be made an iterator again once + // https://github.com/rust-lang/rust/pull/82771 lands on stable. + entries: &'a mut [StylesheetSetEntry<S>], + validity: DataValidity, + dirty: bool, +} + +impl<'a, S> SheetCollectionFlusher<'a, S> +where + S: StylesheetInDocument + PartialEq + 'static, +{ + /// Whether the collection was originally dirty. + #[inline] + pub fn dirty(&self) -> bool { + self.dirty + } + + /// What the state of the sheet data is. + #[inline] + pub fn data_validity(&self) -> DataValidity { + self.validity + } + + /// Returns an iterator over the remaining list of sheets to consume. + pub fn sheets<'b>(&'b self) -> impl Iterator<Item = &'b S> { + self.entries.iter().map(|entry| &entry.sheet) + } +} + +impl<'a, S> SheetCollectionFlusher<'a, S> +where + S: StylesheetInDocument + PartialEq + 'static, +{ + /// Iterates over all sheets and values that we have to invalidate. + /// + /// TODO(emilio): This would be nicer as an iterator but we can't do that + /// until https://github.com/rust-lang/rust/pull/82771 stabilizes. + /// + /// Since we don't have a good use-case for partial iteration, this does the + /// trick for now. + pub fn each(self, mut callback: impl FnMut(&S, SheetRebuildKind) -> bool) { + for potential_sheet in self.entries.iter_mut() { + let committed = mem::replace(&mut potential_sheet.committed, true); + let rebuild_kind = if !committed { + // If the sheet was uncommitted, we need to do a full rebuild + // anyway. + SheetRebuildKind::Full + } else { + match self.validity { + DataValidity::Valid => continue, + DataValidity::CascadeInvalid => SheetRebuildKind::CascadeOnly, + DataValidity::FullyInvalid => SheetRebuildKind::Full, + } + }; + + if !callback(&potential_sheet.sheet, rebuild_kind) { + return; + } + } + } +} + +#[derive(MallocSizeOf)] +struct SheetCollection<S> +where + S: StylesheetInDocument + PartialEq + 'static, +{ + /// The actual list of stylesheets. + /// + /// This is only a list of top-level stylesheets, and as such it doesn't + /// include recursive `@import` rules. + entries: Vec<StylesheetSetEntry<S>>, + + /// The validity of the data that was already there for a given origin. + /// + /// Note that an origin may appear on `origins_dirty`, but still have + /// `DataValidity::Valid`, if only sheets have been appended into it (in + /// which case the existing data is valid, but the origin needs to be + /// rebuilt). + data_validity: DataValidity, + + /// Whether anything in the collection has changed. Note that this is + /// different from `data_validity`, in the sense that after a sheet append, + /// the data validity is still `Valid`, but we need to be marked as dirty. + dirty: bool, +} + +impl<S> Default for SheetCollection<S> +where + S: StylesheetInDocument + PartialEq + 'static, +{ + fn default() -> Self { + Self { + entries: vec![], + data_validity: DataValidity::Valid, + dirty: false, + } + } +} + +impl<S> SheetCollection<S> +where + S: StylesheetInDocument + PartialEq + 'static, +{ + /// Returns the number of stylesheets in the set. + fn len(&self) -> usize { + self.entries.len() + } + + /// Returns the `index`th stylesheet in the set if present. + fn get(&self, index: usize) -> Option<&S> { + self.entries.get(index).map(|e| &e.sheet) + } + + fn remove(&mut self, sheet: &S) { + let index = self.entries.iter().position(|entry| entry.sheet == *sheet); + if cfg!(feature = "gecko") && index.is_none() { + // FIXME(emilio): Make Gecko's PresShell::AddUserSheet not suck. + return; + } + let sheet = self.entries.remove(index.unwrap()); + // Removing sheets makes us tear down the whole cascade and invalidation + // data, but only if the sheet has been involved in at least one flush. + // Checking whether the sheet has been committed allows us to avoid + // rebuilding the world when sites quickly append and remove a + // stylesheet. + // + // See bug 1434756. + if sheet.committed { + self.set_data_validity_at_least(DataValidity::FullyInvalid); + } else { + self.dirty = true; + } + } + + fn contains(&self, sheet: &S) -> bool { + self.entries.iter().any(|e| e.sheet == *sheet) + } + + /// Appends a given sheet into the collection. + fn append(&mut self, sheet: S) { + debug_assert!(!self.contains(&sheet)); + self.entries.push(StylesheetSetEntry::new(sheet)); + // Appending sheets doesn't alter the validity of the existing data, so + // we don't need to change `data_validity` here. + // + // But we need to be marked as dirty, otherwise we'll never add the new + // sheet! + self.dirty = true; + } + + fn insert_before(&mut self, sheet: S, before_sheet: &S) { + debug_assert!(!self.contains(&sheet)); + + let index = self + .entries + .iter() + .position(|entry| entry.sheet == *before_sheet) + .expect("`before_sheet` stylesheet not found"); + + // Inserting stylesheets somewhere but at the end changes the validity + // of the cascade data, but not the invalidation data. + self.set_data_validity_at_least(DataValidity::CascadeInvalid); + self.entries.insert(index, StylesheetSetEntry::new(sheet)); + } + + fn set_data_validity_at_least(&mut self, validity: DataValidity) { + use std::cmp; + + debug_assert_ne!(validity, DataValidity::Valid); + + self.dirty = true; + self.data_validity = cmp::max(validity, self.data_validity); + } + + /// Returns an iterator over the current list of stylesheets. + fn iter(&self) -> StylesheetCollectionIterator<S> { + StylesheetCollectionIterator(self.entries.iter()) + } + + fn flush(&mut self) -> SheetCollectionFlusher<S> { + let dirty = mem::replace(&mut self.dirty, false); + let validity = mem::replace(&mut self.data_validity, DataValidity::Valid); + + SheetCollectionFlusher { + entries: &mut self.entries, + dirty, + validity, + } + } +} + +/// The set of stylesheets effective for a given document. +#[cfg_attr(feature = "servo", derive(MallocSizeOf))] +pub struct DocumentStylesheetSet<S> +where + S: StylesheetInDocument + PartialEq + 'static, +{ + /// The collections of sheets per each origin. + collections: PerOrigin<SheetCollection<S>>, + + /// The invalidations for stylesheets added or removed from this document. + invalidations: StylesheetInvalidationSet, +} + +/// This macro defines methods common to DocumentStylesheetSet and +/// AuthorStylesheetSet. +/// +/// We could simplify the setup moving invalidations to SheetCollection, but +/// that would imply not sharing invalidations across origins of the same +/// documents, which is slightly annoying. +macro_rules! sheet_set_methods { + ($set_name:expr) => { + fn collect_invalidations_for( + &mut self, + device: Option<&Device>, + sheet: &S, + guard: &SharedRwLockReadGuard, + ) { + if let Some(device) = device { + self.invalidations + .collect_invalidations_for(device, sheet, guard); + } + } + + /// Appends a new stylesheet to the current set. + /// + /// No device implies not computing invalidations. + pub fn append_stylesheet( + &mut self, + device: Option<&Device>, + sheet: S, + guard: &SharedRwLockReadGuard, + ) { + debug!(concat!($set_name, "::append_stylesheet")); + self.collect_invalidations_for(device, &sheet, guard); + let collection = self.collection_for(&sheet); + collection.append(sheet); + } + + /// Insert a given stylesheet before another stylesheet in the document. + pub fn insert_stylesheet_before( + &mut self, + device: Option<&Device>, + sheet: S, + before_sheet: S, + guard: &SharedRwLockReadGuard, + ) { + debug!(concat!($set_name, "::insert_stylesheet_before")); + self.collect_invalidations_for(device, &sheet, guard); + + let collection = self.collection_for(&sheet); + collection.insert_before(sheet, &before_sheet); + } + + /// Remove a given stylesheet from the set. + pub fn remove_stylesheet( + &mut self, + device: Option<&Device>, + sheet: S, + guard: &SharedRwLockReadGuard, + ) { + debug!(concat!($set_name, "::remove_stylesheet")); + self.collect_invalidations_for(device, &sheet, guard); + + let collection = self.collection_for(&sheet); + collection.remove(&sheet) + } + + /// Notify the set that a rule from a given stylesheet has changed + /// somehow. + pub fn rule_changed( + &mut self, + device: Option<&Device>, + sheet: &S, + rule: &CssRule, + guard: &SharedRwLockReadGuard, + change_kind: RuleChangeKind, + ) { + if let Some(device) = device { + let quirks_mode = device.quirks_mode(); + self.invalidations.rule_changed( + sheet, + rule, + guard, + device, + quirks_mode, + change_kind, + ); + } + + let validity = match change_kind { + // Insertion / Removals need to rebuild both the cascade and + // invalidation data. For generic changes this is conservative, + // could be optimized on a per-case basis. + RuleChangeKind::Generic | RuleChangeKind::Insertion | RuleChangeKind::Removal => { + DataValidity::FullyInvalid + }, + // TODO(emilio): This, in theory, doesn't need to invalidate + // style data, if the rule we're modifying is actually in the + // CascadeData already. + // + // But this is actually a bit tricky to prove, because when we + // copy-on-write a stylesheet we don't bother doing a rebuild, + // so we may still have rules from the original stylesheet + // instead of the cloned one that we're modifying. So don't + // bother for now and unconditionally rebuild, it's no worse + // than what we were already doing anyway. + // + // Maybe we could record whether we saw a clone in this flush, + // and if so do the conservative thing, otherwise just + // early-return. + RuleChangeKind::StyleRuleDeclarations => DataValidity::FullyInvalid, + }; + + let collection = self.collection_for(&sheet); + collection.set_data_validity_at_least(validity); + } + }; +} + +impl<S> DocumentStylesheetSet<S> +where + S: StylesheetInDocument + PartialEq + 'static, +{ + /// Create a new empty DocumentStylesheetSet. + pub fn new() -> Self { + Self { + collections: Default::default(), + invalidations: StylesheetInvalidationSet::new(), + } + } + + fn collection_for(&mut self, sheet: &S) -> &mut SheetCollection<S> { + let origin = sheet.contents().origin; + self.collections.borrow_mut_for_origin(&origin) + } + + sheet_set_methods!("DocumentStylesheetSet"); + + /// Returns the number of stylesheets in the set. + pub fn len(&self) -> usize { + self.collections + .iter_origins() + .fold(0, |s, (item, _)| s + item.len()) + } + + /// Returns the count of stylesheets for a given origin. + #[inline] + pub fn sheet_count(&self, origin: Origin) -> usize { + self.collections.borrow_for_origin(&origin).len() + } + + /// Returns the `index`th stylesheet in the set for the given origin. + #[inline] + pub fn get(&self, origin: Origin, index: usize) -> Option<&S> { + self.collections.borrow_for_origin(&origin).get(index) + } + + /// Returns whether the given set has changed from the last flush. + pub fn has_changed(&self) -> bool { + !self.invalidations.is_empty() || + self.collections + .iter_origins() + .any(|(collection, _)| collection.dirty) + } + + /// Flush the current set, unmarking it as dirty, and returns a + /// `DocumentStylesheetFlusher` in order to rebuild the stylist. + pub fn flush<E>( + &mut self, + document_element: Option<E>, + snapshots: Option<&SnapshotMap>, + ) -> DocumentStylesheetFlusher<S> + where + E: TElement, + { + debug!("DocumentStylesheetSet::flush"); + + let had_invalidations = self.invalidations.flush(document_element, snapshots); + + DocumentStylesheetFlusher { + collections: &mut self.collections, + had_invalidations, + } + } + + /// Flush stylesheets, but without running any of the invalidation passes. + #[cfg(feature = "servo")] + pub fn flush_without_invalidation(&mut self) -> OriginSet { + debug!("DocumentStylesheetSet::flush_without_invalidation"); + + let mut origins = OriginSet::empty(); + self.invalidations.clear(); + + for (collection, origin) in self.collections.iter_mut_origins() { + if collection.flush().dirty() { + origins |= origin; + } + } + + origins + } + + /// Return an iterator over the flattened view of all the stylesheets. + pub fn iter(&self) -> StylesheetIterator<S> { + StylesheetIterator { + origins: OriginSet::all().iter_origins(), + collections: &self.collections, + current: None, + } + } + + /// Mark the stylesheets for the specified origin as dirty, because + /// something external may have invalidated it. + pub fn force_dirty(&mut self, origins: OriginSet) { + self.invalidations.invalidate_fully(); + for origin in origins.iter_origins() { + // We don't know what happened, assume the worse. + self.collections + .borrow_mut_for_origin(&origin) + .set_data_validity_at_least(DataValidity::FullyInvalid); + } + } +} + +/// The set of stylesheets effective for a given Shadow Root. +#[derive(MallocSizeOf)] +pub struct AuthorStylesheetSet<S> +where + S: StylesheetInDocument + PartialEq + 'static, +{ + /// The actual style sheets. + collection: SheetCollection<S>, + /// The set of invalidations scheduled for this collection. + invalidations: StylesheetInvalidationSet, +} + +/// A struct to flush an author style sheet collection. +pub struct AuthorStylesheetFlusher<'a, S> +where + S: StylesheetInDocument + PartialEq + 'static, +{ + /// The actual flusher for the collection. + pub sheets: SheetCollectionFlusher<'a, S>, + /// Whether any sheet invalidation matched. + pub had_invalidations: bool, +} + +impl<S> AuthorStylesheetSet<S> +where + S: StylesheetInDocument + PartialEq + 'static, +{ + /// Create a new empty AuthorStylesheetSet. + #[inline] + pub fn new() -> Self { + Self { + collection: Default::default(), + invalidations: StylesheetInvalidationSet::new(), + } + } + + /// Whether anything has changed since the last time this was flushed. + pub fn dirty(&self) -> bool { + self.collection.dirty + } + + /// Whether the collection is empty. + pub fn is_empty(&self) -> bool { + self.collection.len() == 0 + } + + /// Returns the `index`th stylesheet in the collection of author styles if present. + pub fn get(&self, index: usize) -> Option<&S> { + self.collection.get(index) + } + + /// Returns the number of author stylesheets. + pub fn len(&self) -> usize { + self.collection.len() + } + + fn collection_for(&mut self, _sheet: &S) -> &mut SheetCollection<S> { + &mut self.collection + } + + sheet_set_methods!("AuthorStylesheetSet"); + + /// Iterate over the list of stylesheets. + pub fn iter(&self) -> StylesheetCollectionIterator<S> { + self.collection.iter() + } + + /// Mark the sheet set dirty, as appropriate. + pub fn force_dirty(&mut self) { + self.invalidations.invalidate_fully(); + self.collection + .set_data_validity_at_least(DataValidity::FullyInvalid); + } + + /// Flush the stylesheets for this author set. + /// + /// `host` is the root of the affected subtree, like the shadow host, for + /// example. + pub fn flush<E>( + &mut self, + host: Option<E>, + snapshots: Option<&SnapshotMap>, + ) -> AuthorStylesheetFlusher<S> + where + E: TElement, + { + let had_invalidations = self.invalidations.flush(host, snapshots); + AuthorStylesheetFlusher { + sheets: self.collection.flush(), + had_invalidations, + } + } +} |