1 files changed, 70 insertions, 0 deletions
diff --git a/servo/components/style/author_styles.rs b/servo/components/style/author_styles.rs
new file mode 100644
index 0000000000..a0223dcecc
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+++ b/servo/components/style/author_styles.rs
@@ -0,0 +1,70 @@
+/* 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 set of author stylesheets and their computed representation, such as the
+//! ones used for ShadowRoot.
+
+use crate::dom::TElement;
+use crate::invalidation::media_queries::ToMediaListKey;
+use crate::shared_lock::SharedRwLockReadGuard;
+use crate::stylesheet_set::AuthorStylesheetSet;
+use crate::stylesheets::StylesheetInDocument;
+use crate::stylist::CascadeData;
+use crate::stylist::Stylist;
+use servo_arc::Arc;
+
+/// A set of author stylesheets and their computed representation, such as the
+/// ones used for ShadowRoot.
+#[derive(MallocSizeOf)]
+pub struct GenericAuthorStyles<S>
+where
+    S: StylesheetInDocument + PartialEq + 'static,
+{
+    /// The sheet collection, which holds the sheet pointers, the invalidations,
+    /// and all that stuff.
+    pub stylesheets: AuthorStylesheetSet<S>,
+    /// The actual cascade data computed from the stylesheets.
+    #[ignore_malloc_size_of = "Measured as part of the stylist"]
+    pub data: Arc<CascadeData>,
+}
+
+pub use self::GenericAuthorStyles as AuthorStyles;
+
+lazy_static! {
+    static ref EMPTY_CASCADE_DATA: Arc<CascadeData> = Arc::new_leaked(CascadeData::new());
+}
+
+impl<S> GenericAuthorStyles<S>
+where
+    S: StylesheetInDocument + PartialEq + 'static,
+{
+    /// Create an empty AuthorStyles.
+    #[inline]
+    pub fn new() -> Self {
+        Self {
+            stylesheets: AuthorStylesheetSet::new(),
+            data: EMPTY_CASCADE_DATA.clone(),
+        }
+    }
+
+    /// Flush the pending sheet changes, updating `data` as appropriate.
+    ///
+    /// TODO(emilio): Need a host element and a snapshot map to do invalidation
+    /// properly.
+    #[inline]
+    pub fn flush<E>(&mut self, stylist: &mut Stylist, guard: &SharedRwLockReadGuard)
+    where
+        E: TElement,
+        S: ToMediaListKey,
+    {
+        let flusher = self
+            .stylesheets
+            .flush::<E>(/* host = */ None, /* snapshot_map = */ None);
+
+        let result = stylist.rebuild_author_data(&self.data, flusher.sheets, guard);
+        if let Ok(Some(new_data)) = result {
+            self.data = new_data;
+        }
+    }
+}