Handle parsing of HTML <style> tags.

This basically re-applies the technique used for HTML <script> tags. With this
extra addition I decided to rename/normalize a few things so it's easier to add
any extra tags in the future. One downside of this setup is that the following
will not be parsed by Oga:

    <style>
        </script>
    </style>

The same applies to script tags containing a literal </style> tag. Since this
particular case is rather unlikely to occur I'm OK with not supporting it as it
_does_ simplify the lexer quite a bit.

Fixes #80

ext/c/lexer.rl

@@ -19,11 +19,11 @@ on `ts` and `te`) so the macro ignores this argument.
 #define advance_line(amount) \
     rb_funcall(self, id_advance_line, 1, INT2NUM(amount));
 
-#define inside_html_script_p() \
-    rb_funcall(self, id_inside_html_script_p, 0) == Qtrue
+#define literal_html_element_p() \
+    rb_funcall(self, id_literal_html_element_p, 0) == Qtrue
 
 ID id_advance_line;
-ID id_inside_html_script_p;
+ID id_literal_html_element_p;
 
 %%machine c_lexer;
 
@@ -174,7 +174,7 @@ void Init_liboga_xml_lexer()
     VALUE cLexer = rb_define_class_under(mXML, "Lexer", rb_cObject);
 
     id_advance_line           = rb_intern("advance_line");
-    id_inside_html_script_p = rb_intern("inside_html_script?");
+    id_literal_html_element_p = rb_intern("literal_html_element?");
 
     rb_define_method(cLexer, "advance_native", oga_xml_lexer_advance, 1);
     rb_define_method(cLexer, "reset_native", oga_xml_lexer_reset, 0);

ext/java/org/liboga/xml/Lexer.rl

@@ -187,14 +187,13 @@ public class Lexer extends RubyObject
     }
 
     /**
-     * Returns true if we're in an HTML script tag. See
-     * Oga::XML::Lexer#inside_html_script? for more information.
+     * See * Oga::XML::Lexer#literal_html_element? for more information.
      */
-    public Boolean inside_html_script_p()
+    public Boolean literal_html_element_p()
     {
         ThreadContext context = this.runtime.getCurrentContext();
 
-        return this.callMethod(context, "inside_html_script?").isTrue();
+        return this.callMethod(context, "literal_html_element?").isTrue();
     }
 }
 

ext/ragel/base_lexer.rl

@@ -328,11 +328,11 @@
         '>' => {
             callback_simple(id_on_element_open_end);
 
-            if ( inside_html_script_p() )
+            if ( literal_html_element_p() )
             {
                 mark = ts + 1;
 
-                fnext script_text;
+                fnext literal_html_element;
             }
             else
             {
@@ -401,11 +401,11 @@
         };
     *|;
 
-    # <script> tags in HTML can contain basically anything except for the
-    # literal "</script>". As a result of this we can't use the regular text
-    # machine.
-    script_text := |*
-        '</script>' => {
+    # Certain tags in HTML can contain basically anything except for the literal
+    # closing tag. Two examples are script and style tags.  As a result of this
+    # we can't use the regular text machine.
+    literal_html_element := |*
+        '</script>' | '</style>' => {
             callback(id_on_text, data, encoding, mark, ts);
 
             mark = 0;

lib/oga/xml/lexer.rb

@@ -41,12 +41,11 @@ module Oga
       attr_reader :html
 
       ##
-      # Element name used to determine if a tag being processed is a Javascript
-      # tag.
+      # Names of HTML tags of which the content should be lexed as-is.
       #
-      # @return [String]
+      # @return [Array]
       #
-      SCRIPT_TAG = 'script'.freeze
+      LITERAL_HTML_ELEMENTS = %w{script style}
 
       ##
       # @param [String|IO] data The data to lex. This can either be a String or
@@ -190,12 +189,12 @@ module Oga
       end
 
       ##
-      # Returns true if the current element is the HTML `<script>` element.
+      # Returns true if the current element's content should be lexed as-is.
       #
       # @return [TrueClass|FalseClass]
       #
-      def inside_html_script?
-        return html? && current_element == SCRIPT_TAG
+      def literal_html_element?
+        return html? && LITERAL_HTML_ELEMENTS.include?(current_element)
       end
 
       ##

lib/oga/xml/text.rb

@@ -12,8 +12,8 @@ module Oga
         node = parent
         root = root_node
 
-        if root.is_a?(Document) and node.is_a?(Element) \
-        and node.name == Lexer::SCRIPT_TAG and root.html?
+        if root.is_a?(Document) and node.is_a?(Element) and root.html? \
+        and Lexer::LITERAL_HTML_ELEMENTS.include?(node.name)
           return super
         else
           return Entities.encode(super)

spec/oga/xml/lexer/html_script_spec.rb

@@ -2,7 +2,7 @@ require 'spec_helper'
 
 describe Oga::XML::Lexer do
   describe 'HTML script elements' do
-    it 'treats all contents of a script tag as plain text' do
+    it 'treats the content of a script tag as plain text' do
       lex('<script>foo <bar</script>', :html => true).should == [
         [:T_ELEM_START, nil, 1],
         [:T_ELEM_NAME, 'script', 1],

spec/oga/xml/lexer/html_style_spec.rb

@@ -0,0 +1,14 @@
+require 'spec_helper'
+
+describe Oga::XML::Lexer do
+  describe 'HTML style elements' do
+    it 'treats the content of a style tag as plain text' do
+      lex('<style>foo <bar</style>', :html => true).should == [
+        [:T_ELEM_START, nil, 1],
+        [:T_ELEM_NAME, 'style', 1],
+        [:T_TEXT, 'foo <bar', 1],
+        [:T_ELEM_END, nil, 1]
+      ]
+    end
+  end
+end

spec/oga/xml/text_spec.rb

@@ -52,6 +52,19 @@ describe Oga::XML::Text do
         text.to_xml.should == 'x > y'
       end
     end
+
+    describe 'inside an HTML <style> element' do
+      it 'does not encode special characters as XML entities' do
+        document = Oga::XML::Document.new(:type => :html)
+        style    = Oga::XML::Element.new(:name => 'style')
+        text     = described_class.new(:text => 'x > y')
+
+        style.children    << text
+        document.children << style
+
+        text.to_xml.should == 'x > y'
+      end
+    end
   end
 
   describe '#inspect' do