New style sytsem: add selector matching

Also make scribt::dom::element::Element::get_attr ASCII case-insensitive
on attribute names, per spec:
http://dom.spec.whatwg.org/#dom-element-getattribute

src/components/script/dom/element.rs

@@ -131,7 +131,8 @@ impl<'self> Element {
     pub fn get_attr(&'self self, name: &str) -> Option<&'self str> {
         // FIXME: Need an each() that links lifetimes in Rust.
         for attr in self.attrs.iter() {
-            if eq_slice(attr.name, name) {
+            // FIXME: only case-insensitive in the HTML namespace (as opposed to SVG, etc.)
+            if attr.name.eq_ignore_ascii_case(name) {
                 let val: &str = attr.value;
                 return Some(val);
             }

src/components/script/style/mod.rs

@@ -2,9 +2,15 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+// The "real" public API
+pub use self::selector_matching::{Stylist, StylesheetOrigin};
+
+
+// Things that need to be public to make the compiler happy
 pub mod stylesheets;
 pub mod errors;
 pub mod selectors;
+pub mod selector_matching;
 pub mod properties;
 pub mod namespaces;
 pub mod media_queries;

src/components/script/style/properties/mod.rs.mako

@@ -5,6 +5,7 @@
 // This file is a Mako template: http://www.makotemplates.org/
 
 use std::ascii::StrAsciiExt;
+use std::at_vec;
 pub use std::iterator;
 pub use cssparser::*;
 pub use style::errors::{ErrorLoggerIterator, log_css_error};
@@ -655,8 +656,8 @@ pub mod shorthands {
 
 
 pub struct PropertyDeclarationBlock {
-    important: ~[PropertyDeclaration],
-    normal: ~[PropertyDeclaration],
+    important: @[PropertyDeclaration],
+    normal: @[PropertyDeclaration],
 }
 
 
@@ -668,6 +669,7 @@ pub fn parse_property_declaration_list(input: ~[Node]) -> PropertyDeclarationBlo
             Decl_AtRule(rule) => log_css_error(
                 rule.location, fmt!("Unsupported at-rule in declaration list: @%s", rule.name)),
             Declaration(Declaration{ location: l, name: n, value: v, important: i}) => {
+                // TODO: only keep the last valid declaration for a given name.
                 let list = if i { &mut important } else { &mut normal };
                 if !PropertyDeclaration::parse(n, v, list) {
                     log_css_error(l, "Invalid property declaration")
@@ -675,7 +677,11 @@ pub fn parse_property_declaration_list(input: ~[Node]) -> PropertyDeclarationBlo
             }
         }
     }
-    PropertyDeclarationBlock { important: important, normal: normal }
+    PropertyDeclarationBlock {
+        // TODO avoid copying?
+        important: at_vec::to_managed_move(important),
+        normal: at_vec::to_managed_move(normal),
+    }
 }
 
 
@@ -795,7 +801,8 @@ fn get_initial_values() -> ComputedValues {
 }
 
 
-pub fn cascade(applicable_declarations: &[PropertyDeclaration],
+// Most specific/important declarations last
+pub fn cascade(applicable_declarations: &[@[PropertyDeclaration]],
                parent_style: Option< &ComputedValues>)
             -> ComputedValues {
     let initial_keep_alive;
@@ -817,14 +824,17 @@ pub fn cascade(applicable_declarations: &[PropertyDeclaration],
                 "Inherit" if property.is_inherited else "Initial"}),
         % endfor
     };
-    for declaration in applicable_declarations.iter() {
-        match declaration {
-            % for property in LONGHANDS:
-                &${property.ident}_declaration(ref value) => {
-                    // Overwrite earlier declarations.
-                    specified.${property.ident} = (*value).clone()  // TODO: can we avoid a copy?
-                }
-            % endfor
+    for sub_list in applicable_declarations.iter() {
+        for declaration in sub_list.iter() {
+            match declaration {
+                % for property in LONGHANDS:
+                    &${property.ident}_declaration(ref value) => {
+                        // Overwrite earlier declarations.
+                        // TODO: can we avoid a copy?
+                        specified.${property.ident} = (*value).clone()
+                    }
+                % endfor
+            }
         }
     }
     // This assumes that the computed and specified values have the same Rust type.

src/components/script/style/selector_matching.rs

@@ -0,0 +1,243 @@
+/* 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 http://mozilla.org/MPL/2.0/. */
+
+use std::ascii::StrAsciiExt;
+use extra::sort::tim_sort;
+
+use style::selectors::*;
+use style::stylesheets::parse_stylesheet;
+use style::media_queries::{Device, Screen};
+use style::properties::{ComputedValues, cascade, PropertyDeclaration};
+use dom::node::{AbstractNode, ScriptView};
+use dom::element::Element;
+
+
+pub enum StylesheetOrigin {
+    UserAgentOrigin,
+    AuthorOrigin,
+    UserOrigin,
+}
+
+
+pub struct Stylist {
+    priv ua_rules: PerOriginRules,
+    priv author_rules: PerOriginRules,
+    priv user_rules: PerOriginRules,
+}
+
+
+impl Stylist {
+    #[inline]
+    pub fn new() -> Stylist {
+        Stylist {
+            ua_rules: PerOriginRules::new(),
+            author_rules: PerOriginRules::new(),
+            user_rules: PerOriginRules::new(),
+        }
+    }
+
+    pub fn add_stylesheet(&mut self, css_source: &str, origin: StylesheetOrigin) {
+        let stylesheet = parse_stylesheet(css_source);
+        let rules = match origin {
+            UserAgentOrigin => &mut self.ua_rules,
+            AuthorOrigin => &mut self.author_rules,
+            UserOrigin => &mut self.user_rules,
+        };
+        let mut has_normal_declarations = false;
+        let mut has_important_declarations = false;
+
+        macro_rules! append(
+            ($priority: ident, $flag: ident) => {
+                if style_rule.declarations.$priority.len() > 0 {
+                    $flag = true;
+                    for selector in style_rule.selectors.iter() {
+                        rules.$priority.push(Rule {
+                            selector: *selector,
+                            declarations: style_rule.declarations.$priority,
+                        })
+                    }
+                }
+            };
+        )
+
+        let device = &Device { media_type: Screen };  // TODO, use Print when printing
+        for style_rule in stylesheet.iter_style_rules(device) {
+            append!(normal, has_normal_declarations);
+            append!(important, has_important_declarations);
+        }
+
+        if has_normal_declarations {
+            tim_sort(rules.normal)
+        }
+        if has_important_declarations {
+            tim_sort(rules.important)
+        }
+    }
+
+    pub fn get_computed_style(&self, element: AbstractNode<ScriptView>,
+                              parent_style: Option<&ComputedValues>,
+                              pseudo_element: Option<PseudoElement>)
+                              -> ComputedValues {
+        assert!(element.is_element())
+        // Only the root does not inherit.
+        // The root has no parent or a non-element parent.
+        assert_eq!(
+            parent_style.is_none(),
+            match element.parent_node() {
+                None => true,
+                Some(ref node) => !node.is_element()
+            }
+        );
+        let mut applicable_declarations = ~[];  // TODO: use an iterator?
+
+        macro_rules! append(
+            ($rules: expr) => {
+                for rule in $rules.iter() {
+                    if matches_selector(rule.selector, element, pseudo_element) {
+                        applicable_declarations.push(rule.declarations)
+                    }
+                }
+            };
+        );
+
+        // In cascading order
+        append!(self.ua_rules.normal);
+        append!(self.user_rules.normal);
+        append!(self.author_rules.normal);
+        // TODO add style attribute
+        append!(self.author_rules.important);
+        append!(self.user_rules.important);
+        append!(self.ua_rules.important);
+
+        cascade(applicable_declarations, parent_style)
+    }
+}
+
+
+struct PerOriginRules {
+    normal: ~[Rule],
+    important: ~[Rule],
+}
+
+impl PerOriginRules {
+    #[inline]
+    fn new() -> PerOriginRules {
+        PerOriginRules { normal: ~[], important: ~[] }
+    }
+}
+
+#[deriving(Clone)]
+struct Rule {
+    selector: @Selector,
+    declarations: @[PropertyDeclaration],
+}
+
+
+impl Ord for Rule {
+    #[inline]
+    fn lt(&self, other: &Rule) -> bool {
+        self.selector.specificity < other.selector.specificity
+    }
+}
+
+
+#[inline]
+fn matches_selector(selector: &Selector, element: AbstractNode<ScriptView>,
+                    pseudo_element: Option<PseudoElement>) -> bool {
+    selector.pseudo_element == pseudo_element &&
+    matches_compound_selector(&selector.compound_selectors, element)
+}
+
+
+fn matches_compound_selector(selector: &CompoundSelector,
+                             element: AbstractNode<ScriptView>) -> bool {
+    if do element.with_imm_element |element| {
+        !do selector.simple_selectors.iter().all |simple_selector| {
+            matches_simple_selector(simple_selector, element)
+        }
+    } {
+        return false
+    }
+    match selector.next {
+        None => true,
+        Some((ref next_selector, combinator)) => {
+            let (siblings, just_one) = match combinator {
+                Child => (false, true),
+                Descendant => (false, false),
+                NextSibling => (true, true),
+                LaterSibling => (true, false),
+            };
+            let mut node = element;
+            loop {
+                match if siblings { node.prev_sibling() } else { node.parent_node() } {
+                    None => return false,
+                    Some(next_node) => node = next_node,
+                }
+                if node.is_element() {
+                    if matches_compound_selector(&**next_selector, node) {
+                        return true
+                    } else if just_one {
+                        return false
+                    }
+                }
+            }
+        }
+    }
+}
+
+#[inline]
+fn matches_simple_selector(selector: &SimpleSelector, element: &Element) -> bool {
+    static WHITESPACE: &'static [char] = &'static [' ', '\t', '\n', '\r', '\x0C'];
+
+    match *selector {
+        // TODO: case-sensitivity depends on the document type
+        LocalNameSelector(ref name) => element.tag_name.eq_ignore_ascii_case(name.as_slice()),
+        NamespaceSelector(_) => false,  // TODO, when the DOM supports namespaces on elements.
+        // TODO: case-sensitivity depends on the document type and quirks mode
+        // TODO: cache and intern IDs on elements.
+        IDSelector(ref id) => element.get_attr("id") == Some(id.as_slice()),
+        // TODO: cache and intern classe names on elements.
+        ClassSelector(ref class) => match element.get_attr("class") {
+            None => false,
+            // TODO: case-sensitivity depends on the document type and quirks mode
+            Some(ref class_attr)
+            => class_attr.split_iter(WHITESPACE).any(|c| c == class.as_slice()),
+        },
+
+        AttrExists(ref attr) => match_attribute(attr, element, |_| true),
+        AttrEqual(ref attr, ref value) => match_attribute(attr, element, |v| v == value.as_slice()),
+        AttrIncludes(ref attr, ref value) => do match_attribute(attr, element) |attr_value| {
+            attr_value.split_iter(WHITESPACE).any(|v| v == value.as_slice())
+        },
+        AttrDashMatch(ref attr, ref value, ref dashing_value)
+        => do match_attribute(attr, element) |attr_value| {
+            attr_value == value.as_slice() || attr_value.starts_with(dashing_value.as_slice())
+        },
+        AttrPrefixMatch(ref attr, ref value) => do match_attribute(attr, element) |attr_value| {
+            attr_value.starts_with(value.as_slice())
+        },
+        AttrSubstringMatch(ref attr, ref value) => do match_attribute(attr, element) |attr_value| {
+            attr_value.contains(value.as_slice())
+        },
+        AttrSuffixMatch(ref attr, ref value) => do match_attribute(attr, element) |attr_value| {
+            attr_value.ends_with(value.as_slice())
+        },
+
+        Negation(ref negated) => {
+            !negated.iter().all(|s| matches_simple_selector(s, element))
+        },
+    }
+}
+
+
+#[inline]
+fn match_attribute(attr: &AttrSelector, element: &Element, f: &fn(&str)-> bool) -> bool {
+    match attr.namespace {
+        Some(_) => false,  // TODO, when the DOM supports namespaces on attributes
+        None => match element.get_attr(attr.name) {
+            None => false,
+            Some(ref value) => f(value.as_slice())
+        }
+    }
+}

src/components/script/style/selectors.rs

@@ -17,6 +17,7 @@ pub struct Selector {
 pub static STYLE_ATTRIBUTE_SPECIFICITY: u32 = 1 << 31;
 
 
+#[deriving(Eq)]
 pub enum PseudoElement {
     Before,
     After,
@@ -40,30 +41,29 @@ pub enum Combinator {
 pub enum SimpleSelector {
     IDSelector(~str),
     ClassSelector(~str),
-    LocalNameSelector{lowercase_name: ~str, cased_name: ~str},
+    LocalNameSelector(~str),
     NamespaceSelector(~str),
 
     // Attribute selectors
     AttrExists(AttrSelector),  // [foo]
     AttrEqual(AttrSelector, ~str),  // [foo=bar]
     AttrIncludes(AttrSelector, ~str),  // [foo~=bar]
-    AttrDashMatch(AttrSelector, ~str),  // [foo|=bar]
+    AttrDashMatch(AttrSelector, ~str, ~str),  // [foo|=bar]  Second string is the first + "-"
     AttrPrefixMatch(AttrSelector, ~str),  // [foo^=bar]
     AttrSubstringMatch(AttrSelector, ~str),  // [foo*=bar]
     AttrSuffixMatch(AttrSelector, ~str),  // [foo$=bar]
 
     // Pseudo-classes
-    Empty,
-    Root,
-    Lang(~str),
-    NthChild(i32, i32),
+//    Empty,
+//    Root,
+//    Lang(~str),
+//    NthChild(i32, i32),
     Negation(~[SimpleSelector]),
     // ...
 }
 
 pub struct AttrSelector {
-    lowercase_name: ~str,
-    cased_name: ~str,
+    name: ~str,
     namespace: Option<~str>,
 }
 
@@ -73,7 +73,7 @@ type Iter = iterator::Peekable<ComponentValue, vec::MoveIterator<ComponentValue>
 
 // None means invalid selector
 pub fn parse_selector_list(input: ~[ComponentValue], namespaces: &NamespaceMap)
-                           -> Option<~[Selector]> {
+                           -> Option<~[@Selector]> {
     let iter = &mut input.move_iter().peekable();
     let first = match parse_selector(iter, namespaces) {
         None => return None,
@@ -99,7 +99,7 @@ pub fn parse_selector_list(input: ~[ComponentValue], namespaces: &NamespaceMap)
 
 // None means invalid selector
 fn parse_selector(iter: &mut Iter, namespaces: &NamespaceMap)
-                  -> Option<Selector> {
+                  -> Option<@Selector> {
     let (first, pseudo_element) = match parse_simple_selectors(iter, namespaces) {
         None => return None,
         Some(result) => result
@@ -130,12 +130,11 @@ fn parse_selector(iter: &mut Iter, namespaces: &NamespaceMap)
             }
         }
     }
-    let selector = Selector{
+    Some(@Selector {
         specificity: compute_specificity(&compound, &pseudo_element),
         compound_selectors: compound,
         pseudo_element: pseudo_element,
-    };
-    Some(selector)
+    })
 }
 
 
@@ -168,12 +167,12 @@ fn compute_specificity(mut selector: &CompoundSelector,
                                     specificity: &mut Specificity) {
         for simple_selector in simple_selectors.iter() {
             match simple_selector {
-                &LocalNameSelector{_} => specificity.element_selectors += 1,
+                &LocalNameSelector(*) => specificity.element_selectors += 1,
                 &IDSelector(*) => specificity.id_selectors += 1,
                 &ClassSelector(*)
                 | &AttrExists(*) | &AttrEqual(*) | &AttrIncludes(*) | &AttrDashMatch(*)
                 | &AttrPrefixMatch(*) | &AttrSubstringMatch(*) | &AttrSuffixMatch(*)
-                | &Empty | &Root | &Lang(*) | &NthChild(*)
+//                | &Empty | &Root | &Lang(*) | &NthChild(*)
                 => specificity.class_like_selectors += 1,
                 &NamespaceSelector(*) => (),
                 &Negation(ref negated)
@@ -229,10 +228,7 @@ fn parse_type_selector(iter: &mut Iter, namespaces: &NamespaceMap)
                 None => (),
             }
             match local_name {
-                Some(name) => simple_selectors.push(LocalNameSelector{
-                    lowercase_name: name.to_ascii_lower(),
-                    cased_name: name,
-                }),
+                Some(name) => simple_selectors.push(LocalNameSelector(name)),
                 None => (),
             }
             Some(Some(simple_selectors))
@@ -369,11 +365,11 @@ fn parse_attribute_selector(content: ~[ComponentValue], namespaces: &NamespaceMa
         Some(Some((_, None))) => fail!("Implementation error, this should not happen."),
         Some(Some((namespace, Some(local_name)))) => AttrSelector {
             namespace: namespace,
-            lowercase_name: local_name.to_ascii_lower(),
-            cased_name: local_name,
+            name: local_name,
         },
     };
     skip_whitespace(iter);
+    // TODO: deal with empty value or value containing whitespace (see spec)
     macro_rules! get_value( () => {{
         skip_whitespace(iter);
         match iter.next() {
@@ -385,7 +381,11 @@ fn parse_attribute_selector(content: ~[ComponentValue], namespaces: &NamespaceMa
         None => AttrExists(attr),  // [foo]
         Some(Delim('=')) => AttrEqual(attr, get_value!()),  // [foo=bar]
         Some(IncludeMatch) => AttrIncludes(attr, get_value!()),  // [foo~=bar]
-        Some(DashMatch) => AttrDashMatch(attr, get_value!()),  // [foo|=bar]
+        Some(DashMatch) => {
+            let value = get_value!();
+            let dashing_value = value + "-";
+            AttrDashMatch(attr, value, dashing_value)  // [foo|=bar]
+        },
         Some(PrefixMatch) => AttrPrefixMatch(attr, get_value!()),  // [foo^=bar]
         Some(SubstringMatch) => AttrSubstringMatch(attr, get_value!()),  // [foo*=bar]
         Some(SuffixMatch) => AttrSuffixMatch(attr, get_value!()),  // [foo$=bar]
@@ -398,8 +398,8 @@ fn parse_attribute_selector(content: ~[ComponentValue], namespaces: &NamespaceMa
 
 fn parse_simple_pseudo_class(name: ~str) -> Option<Either<SimpleSelector, PseudoElement>> {
     match name.to_ascii_lower().as_slice() {
-        "root" => Some(Left(Root)),
-        "empty" => Some(Left(Empty)),
+//        "root" => Some(Left(Root)),
+//        "empty" => Some(Left(Empty)),
 
         // Supported CSS 2.1 pseudo-elements only.
         "before" => Some(Right(Before)),
@@ -415,8 +415,8 @@ fn parse_functional_pseudo_class(name: ~str, arguments: ~[ComponentValue],
                                  namespaces: &NamespaceMap, inside_negation: bool)
                                  -> Option<SimpleSelector> {
     match name.to_ascii_lower().as_slice() {
-        "lang" => parse_lang(arguments),
-        "nth-child" => parse_nth(arguments).map(|&(a, b)| NthChild(a, b)),
+//        "lang" => parse_lang(arguments),
+//        "nth-child" => parse_nth(arguments).map(|&(a, b)| NthChild(a, b)),
         "not" => if inside_negation { None } else { parse_negation(arguments, namespaces) },
         _ => None
     }
@@ -435,16 +435,16 @@ fn parse_pseudo_element(name: ~str) -> Option<PseudoElement> {
 }
 
 
-fn parse_lang(arguments: ~[ComponentValue]) -> Option<SimpleSelector> {
-    let mut iter = arguments.move_skip_whitespace();
-    match iter.next() {
-        Some(Ident(value)) => {
-            if "" == value || iter.next().is_some() { None }
-            else { Some(Lang(value)) }
-        },
-        _ => None,
-    }
-}
+//fn parse_lang(arguments: ~[ComponentValue]) -> Option<SimpleSelector> {
+//    let mut iter = arguments.move_skip_whitespace();
+//    match iter.next() {
+//        Some(Ident(value)) => {
+//            if "" == value || iter.next().is_some() { None }
+//            else { Some(Lang(value)) }
+//        },
+//        _ => None,
+//    }
+//}
 
 
 // Level 3: Parse ONE simple_selector

src/components/script/style/stylesheets.rs

@@ -26,7 +26,7 @@ pub enum CSSRule {
 
 
 pub struct StyleRule {
-    selectors: ~[selectors::Selector],
+    selectors: ~[@selectors::Selector],
     declarations: properties::PropertyDeclarationBlock,
 }
 
@@ -117,7 +117,8 @@ pub fn parse_nested_at_rule(lower_name: &str, rule: AtRule,
 
 
 impl Stylesheet {
-    fn iter_style_rules<'a>(&'a self, device: &'a media_queries::Device) -> StyleRuleIterator<'a> {
+    pub fn iter_style_rules<'a>(&'a self, device: &'a media_queries::Device)
+                                -> StyleRuleIterator<'a> {
         StyleRuleIterator { device: device, stack: ~[(self.rules.as_slice(), 0)] }
     }
 }