1 files changed, 71 insertions, 0 deletions
diff --git a/servo/components/style/stylesheets/media_rule.rs b/servo/components/style/stylesheets/media_rule.rs
new file mode 100644
index 0000000000..cde60a16bf
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+++ b/servo/components/style/stylesheets/media_rule.rs
@@ -0,0 +1,71 @@
+/* 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/. */
+
+//! An [`@media`][media] rule.
+//!
+//! [media]: https://drafts.csswg.org/css-conditional/#at-ruledef-media
+
+use crate::media_queries::MediaList;
+use crate::shared_lock::{DeepCloneParams, DeepCloneWithLock, Locked};
+use crate::shared_lock::{SharedRwLock, SharedRwLockReadGuard, ToCssWithGuard};
+use crate::str::CssStringWriter;
+use crate::stylesheets::CssRules;
+use cssparser::SourceLocation;
+#[cfg(feature = "gecko")]
+use malloc_size_of::{MallocSizeOfOps, MallocUnconditionalShallowSizeOf};
+use servo_arc::Arc;
+use std::fmt::{self, Write};
+use style_traits::{CssWriter, ToCss};
+
+/// An [`@media`][media] rule.
+///
+/// [media]: https://drafts.csswg.org/css-conditional/#at-ruledef-media
+#[derive(Debug, ToShmem)]
+pub struct MediaRule {
+    /// The list of media queries used by this media rule.
+    pub media_queries: Arc<Locked<MediaList>>,
+    /// The nested rules to this media rule.
+    pub rules: Arc<Locked<CssRules>>,
+    /// The source position where this media rule was found.
+    pub source_location: SourceLocation,
+}
+
+impl MediaRule {
+    /// 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.rules.unconditional_shallow_size_of(ops) +
+            self.rules.read_with(guard).size_of(guard, ops)
+    }
+}
+
+impl ToCssWithGuard for MediaRule {
+    // Serialization of MediaRule is not specced.
+    // https://drafts.csswg.org/cssom/#serialize-a-css-rule CSSMediaRule
+    fn to_css(&self, guard: &SharedRwLockReadGuard, dest: &mut CssStringWriter) -> fmt::Result {
+        dest.write_str("@media ")?;
+        self.media_queries
+            .read_with(guard)
+            .to_css(&mut CssWriter::new(dest))?;
+        self.rules.read_with(guard).to_css_block(guard, dest)
+    }
+}
+
+impl DeepCloneWithLock for MediaRule {
+    fn deep_clone_with_lock(
+        &self,
+        lock: &SharedRwLock,
+        guard: &SharedRwLockReadGuard,
+        params: &DeepCloneParams,
+    ) -> Self {
+        let media_queries = self.media_queries.read_with(guard);
+        let rules = self.rules.read_with(guard);
+        MediaRule {
+            media_queries: Arc::new(lock.wrap(media_queries.clone())),
+            rules: Arc::new(lock.wrap(rules.deep_clone_with_lock(lock, guard, params))),
+            source_location: self.source_location.clone(),
+        }
+    }
+}