CSS parsing/selector-matching for pseudo elements

src/components/main/css/matching.rs

@@ -18,12 +18,15 @@ use std::rt;
 use std::task;
 use std::vec;
 use style::{TNode, Stylist, cascade};
+use style::{Before, After};
 
 pub trait MatchMethods {
     fn match_node(&self, stylist: &Stylist);
-    fn match_subtree(&self, stylist: RWArc<Stylist>);
+    fn match_subtree(&self, stylist: ~[RWArc<Stylist>]);
 
+    fn cascade_before_node(&self, parent: Option<LayoutNode>);
     fn cascade_node(&self, parent: Option<LayoutNode>);
+    fn cascade_after_node(&self, parent: Option<LayoutNode>);
     fn cascade_subtree(&self, parent: Option<LayoutNode>);
 }
 
@@ -34,17 +37,22 @@ impl<'self> MatchMethods for LayoutNode<'self> {
                 None => None,
                 Some(ref style_attribute) => Some(style_attribute)
             };
-            stylist.get_applicable_declarations(self, style_attribute, None)
+            stylist.get_applicable_declarations(self, style_attribute)
         };
 
         match *self.mutate_layout_data().ptr {
             Some(ref mut layout_data) => {
-                layout_data.applicable_declarations = applicable_declarations
+                match stylist.get_pseudo_element() {
+                    Some(Before) => layout_data.before_applicable_declarations = applicable_declarations,
+                    Some(After) => layout_data.after_applicable_declarations = applicable_declarations,
+                    None => layout_data.applicable_declarations = applicable_declarations,
+                    _ => {}
+                }
             }
             None => fail!("no layout data")
         }
     }
-    fn match_subtree(&self, stylist: RWArc<Stylist>) {
+    fn match_subtree(&self, stylists: ~[RWArc<Stylist>]) {
         let num_tasks = rt::default_sched_threads() * 2;
         let mut node_count = 0;
         let mut nodes_per_task = vec::from_elem(num_tasks, ~[]);
@@ -63,7 +71,7 @@ impl<'self> MatchMethods for LayoutNode<'self> {
         for nodes in nodes_per_task.move_iter() {
             if nodes.len() > 0 {
                 let chan = chan.clone();
-                let stylist = stylist.clone();
+                let stylists = stylists.clone();
                
                 // FIXME(pcwalton): This transmute is to work around the fact that we have no
                 // mechanism for safe fork/join parallelism. If we had such a thing, then we could
@@ -73,15 +81,19 @@ impl<'self> MatchMethods for LayoutNode<'self> {
                     cast::transmute(nodes)
                 };
 
-                do task::spawn_with((evil, stylist)) |(evil, stylist)| {
+                do task::spawn_with((evil, stylists)) |(evil, stylists)| {
                     let nodes: ~[LayoutNode] = unsafe {
                         cast::transmute(evil)
                     };
 
                     let nodes = Cell::new(nodes);
-                    do stylist.read |stylist| {
+                    for i in range(0, stylists.len()) {
-                        for node in nodes.take().move_iter() {
+                        do stylists[i].read |stylist| {
-                            node.match_node(stylist);
+                            nodes.with_ref(|nodes|{
+                                for node in nodes.iter() {
+                                    node.match_node(stylist);
+                                }
+                            });
                         }
                     }
                     chan.send(());
@@ -94,6 +106,37 @@ impl<'self> MatchMethods for LayoutNode<'self> {
         }
     }
 
+    fn cascade_before_node(&self, parent: Option<LayoutNode>) {
+        let parent_style = match parent {
+            Some(ref parent) => Some(parent.style()),
+            None => None
+        };
+
+        let computed_values = unsafe {
+            Arc::new(cascade(self.borrow_layout_data_unchecked()
+                                 .as_ref()
+                                 .unwrap()
+                                 .before_applicable_declarations,
+                             parent_style.map(|parent_style| parent_style.get())))
+        };
+
+        match *self.mutate_layout_data().ptr {
+            None => fail!("no layout data"),
+            Some(ref mut layout_data) => {
+                let style = &mut layout_data.before_style;
+                match *style {
+                    None => (),
+                    Some(ref previous_style) => {
+                        layout_data.restyle_damage =
+                            Some(incremental::compute_damage(previous_style.get(),
+                                                             computed_values.get()).to_int())
+                    }
+                }
+                *style = Some(computed_values)
+            }
+        }
+    }
+
     fn cascade_node(&self, parent: Option<LayoutNode>) {
         let parent_style = match parent {
             Some(ref parent) => Some(parent.style()),
@@ -125,8 +168,49 @@ impl<'self> MatchMethods for LayoutNode<'self> {
         }
     }
 
+    fn cascade_after_node(&self, parent: Option<LayoutNode>) {
+        let parent_style = match parent {
+            Some(ref parent) => Some(parent.style()),
+            None => None
+        };
+
+        let computed_values = unsafe {
+            Arc::new(cascade(self.borrow_layout_data_unchecked()
+                                 .as_ref()
+                                 .unwrap()
+                                 .after_applicable_declarations,
+                             parent_style.map(|parent_style| parent_style.get())))
+        };
+
+        match *self.mutate_layout_data().ptr {
+            None => fail!("no layout data"),
+            Some(ref mut layout_data) => {
+                let style = &mut layout_data.after_style;
+                match *style {
+                    None => (),
+                    Some(ref previous_style) => {
+                        layout_data.restyle_damage =
+                            Some(incremental::compute_damage(previous_style.get(),
+                                                             computed_values.get()).to_int())
+                    }
+                }
+                *style = Some(computed_values)
+            }
+        }
+    }
+
     fn cascade_subtree(&self, parent: Option<LayoutNode>) {
+        unsafe {
+            if self.borrow_layout_data_unchecked().as_ref().unwrap().before_applicable_declarations.len() > 0 {
+                self.cascade_before_node(parent);
+            }
+        }
         self.cascade_node(parent);
+        unsafe {
+            if self.borrow_layout_data_unchecked().as_ref().unwrap().after_applicable_declarations.len() > 0 {
+                self.cascade_after_node(parent);
+            }
+        }
 
         for kid in self.children() {
             if kid.is_element() {

src/components/main/css/select.rs

@@ -3,16 +3,17 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use style::{Stylesheet, Stylist, UserAgentOrigin, with_errors_silenced};
+use style::PseudoElement;
 use extra::url;
 
 
-pub fn new_stylist() -> Stylist {
+pub fn new_stylist(pseudo_element: Option<PseudoElement>) -> Stylist {
-    let mut stylist = Stylist::new();
+    let mut stylist = Stylist::new(pseudo_element);
     let ua_stylesheet = with_errors_silenced(|| Stylesheet::from_bytes(
         include_bin!("user-agent.css"),
         url::from_str("chrome:///user-agent.css").unwrap(),
         None,
         None));
-    stylist.add_stylesheet(ua_stylesheet, UserAgentOrigin);
+    stylist.add_stylesheet(&ua_stylesheet, UserAgentOrigin);
     stylist
 }

src/components/main/layout/layout_task.rs

@@ -51,6 +51,7 @@ use std::comm::Port;
 use std::task;
 use std::util;
 use style::{AuthorOrigin, Stylesheet, Stylist};
+use style::{Before, After};
 
 /// Information needed by the layout task.
 struct LayoutTask {
@@ -81,7 +82,7 @@ struct LayoutTask {
     /// A cached display list.
     display_list: Option<Arc<DisplayList<OpaqueNode>>>,
 
-    stylist: RWArc<Stylist>,
+    stylists: ~[RWArc<Stylist>],
 
     /// The channel on which messages can be sent to the profiler.
     profiler_chan: ProfilerChan,
@@ -236,6 +237,12 @@ impl LayoutTask {
            profiler_chan: ProfilerChan)
            -> LayoutTask {
 
+        let mut stylists = ~[];
+        let stylist_owners = ~[Some(Before), Some(After), None];
+        for i in range(0, stylist_owners.len()) {
+            stylists.push(RWArc::new(new_stylist(stylist_owners[i])));
+        }
+
         LayoutTask {
             id: id,
             port: port,
@@ -248,7 +255,7 @@ impl LayoutTask {
 
             display_list: None,
 
-            stylist: RWArc::new(new_stylist()),
+            stylists: stylists,
             profiler_chan: profiler_chan,
             opts: opts.clone()
         }
@@ -347,8 +354,12 @@ impl LayoutTask {
 
     fn handle_add_stylesheet(&mut self, sheet: Stylesheet) {
         let sheet = Cell::new(sheet);
-        do self.stylist.write |stylist| {
+        for i in range(0, self.stylists.len()) {
-            stylist.add_stylesheet(sheet.take(), AuthorOrigin)
+            do self.stylists[i].write |stylist| {
+                sheet.with_ref(|sheet|{
+                    stylist.add_stylesheet(sheet, AuthorOrigin);
+                });
+            }
         }
     }
 
@@ -445,7 +456,7 @@ impl LayoutTask {
             ReflowDocumentDamage => {}
             _ => {
                 do profile(time::LayoutSelectorMatchCategory, self.profiler_chan.clone()) {
-                    node.match_subtree(self.stylist.clone());
+                    node.match_subtree(self.stylists.clone());
                     node.cascade_subtree(None);
                 }
             }

src/components/main/layout/util.rs

@@ -127,11 +127,19 @@ impl ElementMapping {
 /// Data that layout associates with a node.
 pub struct LayoutData {
     /// The results of CSS matching for this node.
+    before_applicable_declarations: ~[Arc<~[PropertyDeclaration]>],
+
     applicable_declarations: ~[Arc<~[PropertyDeclaration]>],
 
+    after_applicable_declarations: ~[Arc<~[PropertyDeclaration]>],
+
     /// The results of CSS styling for this node.
+    before_style: Option<Arc<ComputedValues>>,
+
     style: Option<Arc<ComputedValues>>,
 
+    after_style: Option<Arc<ComputedValues>>,
+
     /// Description of how to account for recent style changes.
     restyle_damage: Option<int>,
 
@@ -145,7 +153,11 @@ impl LayoutData {
     pub fn new() -> LayoutData {
         LayoutData {
             applicable_declarations: ~[],
+            before_applicable_declarations: ~[],
+            after_applicable_declarations: ~[],
+            before_style: None,
             style: None,
+            after_style: None,
             restyle_damage: None,
             flow_construction_result: NoConstructionResult,
         }

src/components/style/selector_matching.rs

@@ -244,20 +244,22 @@ pub struct Stylist {
     priv author_rule_map: PerOriginSelectorMap,
     priv user_rule_map: PerOriginSelectorMap,
     priv stylesheet_index: uint,
+    priv pseudo_element: Option<PseudoElement>,
 }
 
 impl Stylist {
     #[inline]
-    pub fn new() -> Stylist {
+    pub fn new(pseudo_element: Option<PseudoElement>) -> Stylist {
         Stylist {
             ua_rule_map: PerOriginSelectorMap::new(),
             author_rule_map: PerOriginSelectorMap::new(),
             user_rule_map: PerOriginSelectorMap::new(),
             stylesheet_index: 0u,
+            pseudo_element: pseudo_element,
         }
     }
 
-    pub fn add_stylesheet(&mut self, stylesheet: Stylesheet, origin: StylesheetOrigin) {
+    pub fn add_stylesheet(&mut self, stylesheet: &Stylesheet, origin: StylesheetOrigin) {
         let rule_map = match origin {
             UserAgentOrigin => &mut self.ua_rule_map,
             AuthorOrigin => &mut self.author_rule_map,
@@ -275,12 +277,14 @@ impl Stylist {
                     $flag = true;
                     for selector in style_rule.selectors.iter() {
                         // TODO: avoid copying?
-                        rule_map.$priority.insert(Rule {
+                        if selector.pseudo_element == self.pseudo_element {
-                                selector: Arc::new(selector.clone()),
+                            rule_map.$priority.insert(Rule {
-                                declarations: style_rule.declarations.$priority.clone(),
+                                    selector: Arc::new(selector.clone()),
-                                index: style_rule_index,
+                                    declarations: style_rule.declarations.$priority.clone(),
-                                stylesheet_index: self.stylesheet_index,
+                                    index: style_rule_index,
+                                    stylesheet_index: self.stylesheet_index,
                             });
+                        }
                     }
                 }
             };
@@ -301,11 +305,10 @@ impl Stylist {
                                        N:TNode<E>>(
                                        &self,
                                        element: &N,
-                                       style_attribute: Option<&PropertyDeclarationBlock>,
+                                       style_attribute: Option<&PropertyDeclarationBlock>)
-                                       pseudo_element: Option<PseudoElement>)
                                        -> ~[Arc<~[PropertyDeclaration]>] {
         assert!(element.is_element());
-        assert!(style_attribute.is_none() || pseudo_element.is_none(),
+        assert!(style_attribute.is_none() || self.pseudo_element.is_none(),
                 "Style attributes do not apply to pseudo-elements");
             
         // In cascading order:
@@ -327,7 +330,7 @@ impl Stylist {
 
         for (i, rule_map) in rule_map_list.iter().enumerate() {
             rule_map_indices[i] = matching_rules_list.len();
-            rule_map.get_all_matching_rules(element, pseudo_element, &mut matching_rules_list);
+            rule_map.get_all_matching_rules(element, self.pseudo_element, &mut matching_rules_list);
         }
         
         let count = matching_rules_list.len();
@@ -370,6 +373,10 @@ impl Stylist {
 
         applicable_declarations
     }
+    
+    pub fn get_pseudo_element(&self) -> Option<PseudoElement> {
+        self.pseudo_element
+    }
 }
 
 struct PerOriginRules {

src/components/style/style.rc

@@ -26,6 +26,7 @@ pub use properties::{cascade, PropertyDeclaration, ComputedValues, computed_valu
 pub use properties::{PropertyDeclarationBlock, parse_style_attribute};  // Style attributes
 pub use errors::with_errors_silenced;
 pub use node::{TElement, TNode};
+pub use selectors::{PseudoElement, Before, After};
 
 mod stylesheets;
 mod errors;