1 files changed, 145 insertions, 0 deletions
diff --git a/servo/components/style/stylesheets/page_rule.rs b/servo/components/style/stylesheets/page_rule.rs
new file mode 100644
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+++ b/servo/components/style/stylesheets/page_rule.rs
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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/. */
+
+//! A [`@page`][page] rule.
+//!
+//! [page]: https://drafts.csswg.org/css2/page.html#page-box
+
+use crate::parser::{Parse, ParserContext};
+use crate::properties::PropertyDeclarationBlock;
+use crate::shared_lock::{DeepCloneParams, DeepCloneWithLock, Locked};
+use crate::shared_lock::{SharedRwLock, SharedRwLockReadGuard, ToCssWithGuard};
+use crate::str::CssStringWriter;
+use crate::values::{AtomIdent, CustomIdent};
+use cssparser::{Parser, SourceLocation};
+#[cfg(feature = "gecko")]
+use malloc_size_of::{MallocSizeOf, MallocSizeOfOps, MallocUnconditionalShallowSizeOf};
+use servo_arc::Arc;
+use std::fmt::{self, Write};
+use style_traits::{CssWriter, ParseError, ToCss};
+
+/// Type of a single [`@page`][page selector]
+///
+/// We do not support pseudo selectors yet.
+/// [page-selectors]: https://drafts.csswg.org/css2/page.html#page-selectors
+#[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss, ToShmem)]
+pub struct PageSelector(pub AtomIdent);
+
+impl PageSelector {
+    /// Checks if the ident matches a page-name's ident.
+    ///
+    /// This does not currently take pseudo selectors into account.
+    #[inline]
+    pub fn ident_matches(&self, other: &CustomIdent) -> bool {
+        self.0 .0 == other.0
+    }
+}
+
+impl Parse for PageSelector {
+    fn parse<'i, 't>(
+        _context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Self, ParseError<'i>> {
+        let s = input.expect_ident()?;
+        Ok(PageSelector(AtomIdent::from(&**s)))
+    }
+}
+
+/// A list of [`@page`][page selectors]
+///
+/// [page-selectors]: https://drafts.csswg.org/css2/page.html#page-selectors
+#[derive(Clone, Debug, Default, MallocSizeOf, ToCss, ToShmem)]
+#[css(comma)]
+pub struct PageSelectors(#[css(iterable)] pub Box<[PageSelector]>);
+
+impl PageSelectors {
+    /// Creates a new PageSelectors from a Vec, as from parse_comma_separated
+    #[inline]
+    pub fn new(s: Vec<PageSelector>) -> Self {
+        PageSelectors(s.into())
+    }
+    /// Returns true iff there are any page selectors
+    #[inline]
+    pub fn is_empty(&self) -> bool {
+        self.as_slice().is_empty()
+    }
+    /// Get the underlying PageSelector data as a slice
+    #[inline]
+    pub fn as_slice(&self) -> &[PageSelector] {
+        &*self.0
+    }
+}
+
+impl Parse for PageSelectors {
+    fn parse<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Self, ParseError<'i>> {
+        Ok(PageSelectors::new(input.parse_comma_separated(|i| {
+            PageSelector::parse(context, i)
+        })?))
+    }
+}
+
+/// A [`@page`][page] rule.
+///
+/// This implements only a limited subset of the CSS
+/// 2.2 syntax.
+///
+/// [page]: https://drafts.csswg.org/css2/page.html#page-box
+/// [page-selectors]: https://drafts.csswg.org/css2/page.html#page-selectors
+#[derive(Clone, Debug, ToShmem)]
+pub struct PageRule {
+    /// Selectors of the page-rule
+    pub selectors: PageSelectors,
+    /// The declaration block this page rule contains.
+    pub block: Arc<Locked<PropertyDeclarationBlock>>,
+    /// The source position this rule was found at.
+    pub source_location: SourceLocation,
+}
+
+impl PageRule {
+    /// Measure heap usage.
+    #[cfg(feature = "gecko")]
+    pub fn size_of(&self, guard: &SharedRwLockReadGuard, ops: &mut MallocSizeOfOps) -> usize {
+        // Measurement of other fields may be added later.
+        self.block.unconditional_shallow_size_of(ops) +
+            self.block.read_with(guard).size_of(ops) +
+            self.selectors.size_of(ops)
+    }
+}
+
+impl ToCssWithGuard for PageRule {
+    /// Serialization of PageRule is not specced, adapted from steps for
+    /// StyleRule.
+    fn to_css(&self, guard: &SharedRwLockReadGuard, dest: &mut CssStringWriter) -> fmt::Result {
+        dest.write_str("@page ")?;
+        if !self.selectors.is_empty() {
+            self.selectors.to_css(&mut CssWriter::new(dest))?;
+            dest.write_char(' ')?;
+        }
+        dest.write_str("{ ")?;
+        let declaration_block = self.block.read_with(guard);
+        declaration_block.to_css(dest)?;
+        if !declaration_block.declarations().is_empty() {
+            dest.write_char(' ')?;
+        }
+        dest.write_char('}')
+    }
+}
+
+impl DeepCloneWithLock for PageRule {
+    fn deep_clone_with_lock(
+        &self,
+        lock: &SharedRwLock,
+        guard: &SharedRwLockReadGuard,
+        _params: &DeepCloneParams,
+    ) -> Self {
+        PageRule {
+            selectors: self.selectors.clone(),
+            block: Arc::new(lock.wrap(self.block.read_with(&guard).clone())),
+            source_location: self.source_location.clone(),
+        }
+    }
+}