styling: added preliminary styling application

src/css.rs

@@ -1,9 +1,9 @@
 use std;
 
-struct SimpleSelector {
-    tag_name: Option<String>,
-    id: Option<String>,
-    class: Vec<String>,
+pub struct SimpleSelector {
+    pub tag_name: Option<String>,
+    pub id: Option<String>,
+    pub class: Vec<String>,
 }
 
 struct ChainSelector {
@@ -12,7 +12,7 @@ struct ChainSelector {
     class: Vec<Vec<String>>,
 }
 
-enum Selector {
+pub enum Selector {
     Simple(SimpleSelector),
     //Chain(ChainSelector),
 }
@@ -43,7 +43,8 @@ impl std::fmt::Display for Selector {
     }
 }
 
-enum Unit {
+#[derive(Clone)]
+pub enum Unit {
     Px,
     Em,
     Rm,
@@ -65,14 +66,16 @@ impl std::fmt::Display for Unit {
     }
 }
 
-struct Color {
+#[derive(Clone)]
+pub struct Color {
     r: u8,
     g: u8,
     b: u8,
     a: u8,
 }
 
-enum Value {
+#[derive(Clone)]
+pub enum Value {
     Keyword(String),
     Length(f32, Unit),
     ColorValue(Color),
@@ -88,9 +91,9 @@ impl std::fmt::Display for Value {
     }
 }
 
-struct Declaration {
-    name: String,
-    value: Value,
+pub struct Declaration {
+    pub name: String,
+    pub value: Value,
 }
 
 impl std::fmt::Display for Declaration {
@@ -99,9 +102,9 @@ impl std::fmt::Display for Declaration {
     }
 }
 
-struct Rule {
-    selectors: Vec<Selector>,
-    declarations: Vec<Declaration>,
+pub struct Rule {
+    pub selectors: Vec<Selector>,
+    pub declarations: Vec<Declaration>,
 }
 
 impl std::fmt::Display for Rule {
@@ -124,7 +127,7 @@ impl std::fmt::Display for Rule {
 }
 
 pub struct Stylesheet {
-    rules: Vec<Rule>,
+    pub rules: Vec<Rule>,
 }
 
 impl std::fmt::Display for Stylesheet {

src/dom.rs

@@ -1,4 +1,4 @@
-use std::collections::HashMap;
+use std::collections::{HashMap,HashSet};
 use std;
 
 use css;
@@ -7,17 +7,30 @@ pub struct Attr {
   attrs: HashMap<String, String>,
 }
 
-struct EData {
-    name: String,
-    attr: Attr,
+pub struct EData {
+    pub name: String,
+    pub attr: Attr,
 }
 
-struct SData {
+impl EData {
+    pub fn id(&self) -> Option<&String> {
+        self.attr.attrs.get("id")
+    }
+
+    pub fn classes(&self) -> HashSet<&str> {
+        match self.attr.attrs.get("class") {
+            Some(classlist) => classlist.split(' ').collect(),
+            None => HashSet::new()
+        }
+    }
+}
+
+pub struct SData {
     attr: Attr,
     content: css::Stylesheet,
 }
 
-enum NType {
+pub enum NType {
     Text(String),
     Comment(String),
     Element(EData),
@@ -25,8 +38,8 @@ enum NType {
 }
 
 pub struct Node {
-    children: Vec<Node>,
-    ntype: NType,
+    pub children: Vec<Node>,
+    pub ntype: NType,
 }
 
 pub fn text(d: String) -> Node {

src/main.rs

@@ -6,6 +6,7 @@ use std::fs::File;
 pub mod css;
 pub mod dom;
 pub mod html;
+pub mod styling;
 
 fn read_source(filename: String) -> String {
     let mut str = String::new();

src/styling.rs

@@ -0,0 +1,73 @@
+use std::collections::HashMap;
+
+use css;
+use dom;
+
+type Properties = HashMap<String, css::Value>;
+
+pub struct Node<'a> {
+    node: & 'a dom::Node,
+    values: Properties,
+    children: Vec<Node<'a>>,
+}
+
+fn matches(elem: &dom::EData, selector: &css::Selector) -> bool {
+    match *selector {
+        css::Selector::Simple(ref s) => matches_simple(elem, s)
+    }
+}
+
+fn matches_simple(elem: &dom::EData, selector: &css::SimpleSelector) -> bool {
+    if selector.tag_name.iter().any(|name| elem.name != *name) {
+        return false;
+    }
+
+    if selector.id.iter().any(|id| elem.id() != Some(id)) {
+        return false;
+    }
+
+    let elem_classes = elem.classes();
+    if selector.class.iter().any(|class| !elem_classes.contains(&**class)) {
+        return false;
+    }
+
+    return true;
+}
+
+type Rule<'a> = (css::Specificity, &'a css::Rule);
+
+fn match_rule<'a>(elem: &dom::EData, rule: &'a css::Rule) -> Option<Rule<'a>> {
+    rule.selectors.iter()
+        .find(|selector| matches(elem, *selector))
+        .map(|selector| (selector.specificity(), rule))
+}
+
+fn matching_rules<'a>(elem: &dom::EData, stylesheet: &'a css::Stylesheet) -> Vec<Rule<'a>> {
+    stylesheet.rules.iter().filter_map(|rule| match_rule(elem, rule)).collect()
+}
+
+fn values(elem: &dom::EData, stylesheet: &css::Stylesheet) -> Properties {
+    let mut values = HashMap::new();
+    let mut rules = matching_rules(elem, stylesheet);
+
+    rules.sort_by(|&(a, _), &(b, _)| a.cmp(&b));
+    for (_, rule) in rules {
+        for decl in &rule.declarations {
+            values.insert(decl.name.clone(), decl.value.clone());
+        }
+    }
+    return values;
+}
+
+pub fn style_tree<'a>(root: &'a dom::Node, stylesheet: &'a css::Stylesheet) -> Node<'a> {
+    Node {
+        node: root,
+        values: match root.ntype {
+            dom::NType::Element(ref elem) => values(elem, stylesheet),
+            dom::NType::Text(_) => HashMap::new(),
+            dom::NType::Comment(_) => HashMap::new(),
+            dom::NType::Stylesheet(_) => HashMap::new(),
+        },
+        children: root.children.iter().map(|child| style_tree(child, stylesheet)).collect(),
+    }
+}