Implemented a parser for a subset of css and added a hack for guessing when .css files exist.

src/servo/content.rs

@@ -3,6 +3,7 @@ export content;
 
 import result::extensions;
 import dom::rcu::writer_methods;
+import dom::style;
 import dom=dom::base;
 import layout::layout;
 import js::rust::methods;
@@ -38,11 +39,36 @@ fn content(to_layout: chan<layout::msg>) -> chan<msg> {
               parse(filename) {
                 #debug["content: Received filename `%s` to parse", filename];
 
+                // TODO actually parse where the css sheet should be
+                // Replace .html with .css and try to open a stylesheet
+                assert filename.ends_with(".html");
+                let new_file = filename.substr(0u, filename.len() - 5u)
+                    + ".css";
+
+                // Send off a task to parse the stylesheet
+                let css_port = comm::port();
+                let css_chan = comm::chan(css_port);
+                task::spawn {||
+                    let css_stream = parser::lexer::
+                        spawn_css_parser_task(new_file);
+                    let css_rules = parser::css_builder::
+                        build_stylesheet(css_stream);
+                    css_chan.send(css_rules);
+                };
+
                 // Note: we can parse the next document in parallel
                 // with any previous documents.
-                let stream = lexer::spawn_html_parser_task(filename);
+                let stream = parser::lexer::spawn_html_parser_task(filename);
                 let root = parser::html_builder::build_dom(scope, stream);
 
+                // Collect the css stylesheet
+                let css_rules = comm::recv(css_port);
+                
+                // Apply the css rules to the dom tree:
+                // TODO
+                #debug["%s",style::print_sheet(css_rules)];
+                
+               
                 // Now, join the layout so that they will see the latest
                 // changes we have made.
                 join_layout(scope, to_layout);

src/servo/dom/style.rs

@@ -7,7 +7,7 @@ enum display_type{
 }
 
 enum style_decl{
-    font_size(uint),
+    font_size(uint), // Currently assumes format '# pt'
     display(display_type),
     text_color(uint),
     background_color(uint)
@@ -27,10 +27,9 @@ enum selector{
     sibling(~selector, ~selector)
 }
 
-type rule = (selector, [style_decl]);
-
-type stylesheet = [rule];
+type rule = ([~selector], [style_decl]);
 
+type stylesheet = [~rule];
 
 fn print_list<T>(list : [T], print : fn(T) -> str) -> str {
     let l = vec::len(list);
@@ -48,6 +47,23 @@ fn print_list<T>(list : [T], print : fn(T) -> str) -> str {
     ret res;
 } 
 
+fn print_list_vert<T>(list : [T], print : fn(T) -> str) -> str {
+    let l = vec::len(list);
+    if l == 0u { ret "" }
+
+    let mut res = "-";
+    res += print(list[0]);
+    let mut i = 1u;
+    
+    while i < l { 
+        res += "\n-";
+        res += print(list[i]);
+        i += 1u;
+    }
+    
+    ret res;
+} 
+
 fn print_display(dis_ty : display_type) -> str {
     alt dis_ty { 
       block { "block" } 
@@ -57,7 +73,7 @@ fn print_display(dis_ty : display_type) -> str {
 
 fn print_style(decl : style_decl) -> str{
     alt decl {
-      font_size(s) { #fmt("Font size = %u px", s) }
+      font_size(s) { #fmt("Font size = %u pt", s) }
       display(dis_ty) { #fmt("Display style = %s", print_display(dis_ty)) }
       text_color(c) { #fmt("Text color = 0x%06x", c) }
       background_color(c) { #fmt("Background color = 0x%06x", c) }
@@ -73,7 +89,7 @@ fn print_attr(attribute : attr) -> str {
     }
 }
 
-fn print_selector(select : ~selector) -> str {
+fn print_selector(&&select : ~selector) -> str {
     alt *select {
       element(s, attrs) { #fmt("Element %s with attributes: %s", s, 
                                print_list(attrs, print_attr)) }
@@ -86,39 +102,39 @@ fn print_selector(select : ~selector) -> str {
     }
 }
 
-fn print_rule(rule : rule) -> str {
-    alt rule {
-      (sel, styles) {
-        let sel_str = print_selector(~(copy sel));
+fn print_rule(&&rule : ~rule) -> str {
+    alt *rule {
+      (sels, styles) {
+        let sel_str = print_list(sels, print_selector);
         let sty_str = print_list(styles, print_style);        
         
-        #fmt("Selector: %s, Style: {%s}", sel_str, sty_str)
+        #fmt("Selectors: %s; Style: {%s}", sel_str, sty_str)
       }
     }
 }
 
 fn print_sheet(sheet : stylesheet) -> str {
-    #fmt("CSS Rules: %s", print_list(sheet, print_rule))
+    #fmt("CSS Rules:\n%s", print_list_vert(sheet, print_rule))
 }
 
 #[test]
 fn test_pretty_print() {
-    let test1 = [(element("p", []), [font_size(32u)])];
+    let test1 = [~([~element("p", [])], [font_size(32u)])];
     let actual1 = print_sheet(test1);
-    let expected1 = "CSS Rules: Selector: Element p with attributes: ," +
-        " Style: {Font size = 32 px}";
+    let expected1 = "CSS Rules:\n-Selectors: Element p with attributes: ;" +
+        " Style: {Font size = 32 pt}";
 
     assert(actual1 == expected1);
 
     let elmt1 = ~element("*", []);
     let elmt2 = ~element("body", [exact("class", "2")]);
 
-    let test2 = [(descendant(elmt1, elmt2),
+    let test2 = [~([~descendant(elmt1, elmt2)],
                   [display(block), text_color(0u)])];
 
     let actual2 = print_sheet(test2);
-    let expected2 =  "CSS Rules: Selector: (Element * with attributes: ) " + 
-        "(Element body with attributes: [class = 2]), " + 
+    let expected2 =  "CSS Rules:\n-Selectors: (Element * with attributes: ) "
+        + "(Element body with attributes: [class = 2]); " + 
         "Style: {Display style = block, Text color = 0x000000}";
 
     assert(actual2 == expected2);

src/servo/layout/base.rs

@@ -165,7 +165,7 @@ mod test {
         for tree::each_child(btree, root) {|c|
             r += flat_bounds(c);
         }
-        ret r + [root.bounds];
+        ret r + [copy root.bounds];
     }
 
     #[test]

src/servo/parser/css_builder.rs

@@ -0,0 +1,262 @@
+#[doc="Constructs a list of style rules from a token stream"]
+
+// TODO: fail according to the css spec instead of failing when things
+// are not as expected
+
+import dom::style::*;
+import parser::lexer::css::{token, to_start_desc, to_end_desc,
+                            to_descendant, to_child, to_sibling,
+                            to_comma, to_elmt, to_attr, to_desc,
+                            to_eof};
+import comm::recv;
+
+type token_reader = {stream : port<token>, mut lookahead : option<token>};
+
+impl methods for token_reader {
+    fn get() -> token {
+        alt self.lookahead {
+          some(tok)  { self.lookahead = none; tok }
+          none       { recv(self.stream) }
+        }
+    }
+
+    fn unget(tok : token) {
+        self.lookahead = some(tok);
+    }
+}
+
+fn parse_element(reader : token_reader) -> option<~selector> {
+    // Get the current element type
+    let elmt_name = alt reader.get() {
+      to_elmt(tag)  { tag }
+      to_eof        { ret none; }
+      _             { fail "Expected an element" }
+    };
+
+    let mut attr_list = [];
+
+    // Get the attributes associated with that element
+    loop {
+        let tok = reader.get();
+        alt tok {
+          to_attr(attr)       { attr_list += [attr]; }
+          to_start_desc | to_descendant | to_child | to_sibling 
+          | to_comma {
+            reader.unget(tok); 
+            break;
+          }
+          to_eof              { ret none; }          
+          to_elmt(_)          { fail "Unexpected second element without " +
+                                   "relation to first element"; }
+          to_end_desc         { fail "Unexpected '}'"; }
+          to_desc(_, _)       { fail "Unexpected description"; }
+        }
+    }
+        
+    ret some(~element(elmt_name, attr_list));
+}
+
+// Currently colors are supported in rgb(a,b,c) form and also by
+// keywords for several common colors.
+// TODO: extend this
+fn parse_color(color : str) -> uint {
+    let blue_unit = 1u;
+    let green_unit = 256u;
+    let red_unit = 256u * 256u;
+    
+    let result_color = if color.starts_with("rgb(") {
+        let color_vec = str::bytes(color);
+        let mut i = 4u;
+        let mut red_vec = [];
+        let mut green_vec = [];
+        let mut blue_vec = [];
+
+        while i < color_vec.len() && color_vec[i] != ',' as u8 {
+            red_vec += [color_vec[i]];
+            i += 1u;
+        }
+
+        i += 1u;
+
+        while i < color_vec.len() && color_vec[i] != ',' as u8 {
+            green_vec += [color_vec[i]];
+            i += 1u;
+        }
+
+        i += 1u;
+         
+        while i < color_vec.len() && color_vec[i] != ',' as u8 {
+            blue_vec += [color_vec[i]];
+            i += 1u;
+        }
+
+        // TODO, fail by ignoring the rule instead of setting the
+        // color to black
+
+        let blue_intense = alt uint::from_str(str::from_bytes(blue_vec)) {
+          some(c)  { c }
+          none     { 0u }
+        };
+
+        let green_intense = alt uint::from_str(str::from_bytes(green_vec)) { 
+          some(c)  { c }
+          none     { 0u }
+        };
+
+        let red_intense = alt uint::from_str(str::from_bytes(red_vec)) { 
+          some(c)  { c }
+          none     { 0u }
+        };
+
+
+        blue_unit * blue_intense + green_intense * green_unit
+            + red_intense * red_unit
+    } else {
+        alt color {
+          "red"   { red_unit * 255u }
+          "blue"  { blue_unit * 255u }
+          "green" { green_unit * 255u}
+          "white" { red_unit * 256u - 1u }
+          "black" { 0u }
+          // TODO, fail by ignoring the rule instead of setting the
+          // color to black
+          _       { #debug["Unrecognized color %s", color]; 0u }
+        }
+    };
+
+    ret result_color;
+}
+
+fn parse_rule(reader : token_reader) -> option<~rule> {
+    let mut sel_list = [];
+    let mut desc_list = [];
+
+    // Collect all the selectors that this rule applies to
+    loop {
+        let mut cur_sel;
+
+        alt parse_element(reader) {
+          some(elmt)  { cur_sel <- elmt; }
+          none        { ret none; } // we hit an eof in the middle of a rule
+        }
+
+        loop {
+            let tok = reader.get();
+            alt tok {
+              to_descendant {
+                alt parse_element(reader) {
+                  some(elmt)   { 
+                    let built_sel <- cur_sel;
+                    let new_sel <- elmt;
+                    cur_sel <- ~descendant(built_sel, new_sel)
+                  }
+                  none         { ret none; }
+                }
+              }
+              to_child {
+                alt parse_element(reader) {
+                  some(elmt)   { 
+                    let built_sel <- cur_sel;
+                    let new_sel <- elmt;
+                    cur_sel <- ~child(built_sel, new_sel)
+                  }
+                  none         { ret none; }
+                }
+              }
+              to_sibling {
+                alt parse_element(reader) {
+                  some(elmt)   { 
+                    let built_sel <- cur_sel;
+                    let new_sel <- elmt;
+                    cur_sel <- ~sibling(built_sel, new_sel)
+                  }
+                  none         { ret none; }
+                }
+              }
+              to_start_desc {
+                let built_sel <- cur_sel; 
+                sel_list += [built_sel];
+                reader.unget(to_start_desc);
+                break;
+              }
+              to_comma      {
+                let built_sel <- cur_sel;
+                sel_list += [built_sel];
+                reader.unget(to_comma);
+                break;
+              }
+              to_attr(_) | to_end_desc | to_elmt(_) | to_desc(_, _) {
+                fail #fmt["Unexpected token %? in elements", tok];
+              }
+              to_eof        { ret none; }
+            }
+        }
+
+        // check if we should break out of the nesting loop as well
+        let tok = reader.get();
+        alt tok {
+          to_start_desc { break; }
+          to_comma      { }
+          _             { reader.unget(tok); }
+        }
+    }
+    
+    // Get the description to be applied to the selector
+    loop {
+        let tok = reader.get();
+        alt tok {
+          to_end_desc   { break; }
+          to_desc(prop, val) {
+            alt prop {
+              "font-size" {
+                // TODO, support more ways to declare a font size than # pt
+                assert val.ends_with("pt");
+                let num = val.substr(0u, val.len() - 2u);
+                
+                alt uint::from_str(num) {
+                  some(n)    { desc_list += [font_size(n)]; }
+                  none       { fail "Nonnumber provided as font size"; }
+                }
+              }
+              "display" {
+                alt val {
+                  "inline"   { desc_list += [display(inline)]; }
+                  "block"    { desc_list += [display(block)]; }
+                  _          { #debug["Recieved unknown display value '%s'",
+                                      val]; }
+                }
+              }
+              "color" {
+                desc_list += [text_color(parse_color(val))];
+              }
+              "background-color" {
+                desc_list += [background_color(parse_color(val))];
+              }
+              _          { #debug["Recieved unknown style property '%s'",
+                                  val]; }
+            }
+          }
+          to_eof        { ret none; }
+          to_start_desc | to_descendant | to_child | to_sibling
+          | to_comma | to_elmt(_) | to_attr(_)  {
+            fail #fmt["Unexpected token %? in description", tok]; 
+          }
+        }
+    }
+
+    ret some(~(sel_list, desc_list));
+}
+
+fn build_stylesheet(stream : port<token>) -> [~rule] {
+    let mut rule_list = [];
+    let reader = {stream : stream, mut lookahead : none};
+
+    loop {
+        alt parse_rule(reader) {
+          some(rule)   { let r <- rule; rule_list += [r]; }
+          none         { break; }
+        }
+    }
+
+    ret rule_list;
+}

src/servo/parser/lexer.rs

@@ -307,7 +307,7 @@ mod css {
               '>' as u8  { to_child }
               '+' as u8  { to_sibling }
               ',' as u8  { to_comma }
-              _          { to_descendant }                             
+              _          { self.unget(c); to_descendant }
             };
 
             self.eat_whitespace();
@@ -316,14 +316,22 @@ mod css {
         }
 
         fn parse_css_element(c : u8) -> token {
-            /* Check for special attributes with an implied element.*/
+            assert self.lookahead.is_none();
+
+            /* Check for special attributes with an implied element,
+            or a wildcard which is not a alphabet character.*/
             if c == '.' as u8 || c == '#' as u8 {
                 self.state = ps_css_attribute;
                 self.unget(c);
                 ret to_elmt("*");
+            } else if c == '*' as u8 {
+                self.state = ps_css_attribute;
+                ret to_elmt("*");
             }
 
+            self.unget(c);
             let element = self.parse_ident();
+
             self.state = ps_css_attribute;
             
             ret to_elmt(element);
@@ -389,7 +397,11 @@ mod css {
         fn parse_css_description(c: u8) -> token {
             let mut ch = c;
 
-            if ch.is_whitespace() {
+            if ch == '}' as u8 {
+                self.state = ps_css_elmt;
+                self.eat_whitespace();
+                ret to_end_desc;
+            } else if ch.is_whitespace() {
                 self.eat_whitespace();
 
                 alt self.get() {
@@ -439,7 +451,7 @@ mod css {
                     if desc_val.len() == 0u {
                         fail "Expected descriptor value";
                     } else {
-                        self.state = ps_css_elmt;
+                        self.unget('}' as u8);
                         break;
                     }
                 } else if ch == ';' as u8 {
@@ -485,16 +497,29 @@ fn spawn_css_parser_task(filename: str) -> port<css::token> {
     let result_port = port();
     let result_chan = chan(result_port);
     task::spawn {||
-        let file_data = io::read_whole_file(filename).get();
-        let reader = io::bytes_reader(file_data);
-        
         assert filename.ends_with(".css");
-        let parser : parser = parser(reader, ps_css_elmt);
 
-        loop {
-            let token = parser.parse_css();
-            result_chan.send(token);
-            if token == css::to_eof { break; }
+        let file_try = io::read_whole_file(filename);
+
+        // Check if the given css file existed, if it does, parse it,
+        // otherwise just send an eof.  This is a hack to allow
+        // guessing that if foo.html exists, foo.css is the
+        // corresponding stylesheet.
+        if file_try.is_success() {
+            #debug["Lexing css sheet %s", filename];
+            let file_data = file_try.get();
+            let reader = io::bytes_reader(file_data);
+        
+            let parser : parser = parser(reader, ps_css_elmt);
+
+            loop {
+                let token = parser.parse_css();
+                result_chan.send(token);
+                if token == css::to_eof { break; }
+            }
+        } else {
+            #debug["Failed to open css sheet %s", filename];
+            result_chan.send(css::to_eof);
         }
     };
     ret result_port;

src/servo/servo.rc

@@ -51,6 +51,7 @@ mod layout {
 mod parser {
     mod lexer;
     mod html_builder;
+    mod css_builder;
 }
 
 mod platform {

src/servo/servo.rs

@@ -1,6 +1,5 @@
 import comm::*;
 import parser::lexer;
-//import parser::lexer::util_methods;
 import result::extensions;
 import gfx::renderer;
 import platform::osmain;

src/test/test.css

@@ -0,0 +1,5 @@
+p {font-size : 12pt}
+p img {color : rgb(0,255,0); display : block }
+p.blue > p.green + p.red { background-color : blue ;color : green }
+img[class] .pastoral *[lang|=en] { display:inline}
+.book > #novel + *[type=novella] p { color : blue; color : white }