Merge pull request #12 from giuseongit/experimental/better-engine

New parsing engine

src/crystagiri/html.cr

@@ -49,32 +49,98 @@ module Crystagiri
     # Initialize an Html object from Html source
     def initialize(@content : String)
       @nodes = XML.parse_html @content
+
+      @ids = Hash(String, XML::Node).new
+      @tags = Hash(String, Array(XML::Node)).new
+      @classes = Hash(String, Array(XML::Node)).new
+
+      visit @nodes  # Build internal pointer map
+    end
+
+    # Functions used to populate internal maps
+
+    private def add_id(id : String, node : XML::Node)
+      @ids[id] = node
+    end
+
+    private def add_node(node : XML::Node)
+      if @tags[node.name]? == nil
+        @tags[node.name] = [] of XML::Node
+      end
+      @tags[node.name] << node
+    end
+
+    private def add_class(klass : String, node : XML::Node)
+      if @classes[klass]? == nil
+        @classes[klass] = [] of XML::Node
+      end
+      @classes[klass] << node
+    end
+
+    # Depth-first visit. Given a node, extract metadata from
+    # node (if exists), then visit each child.
+    private def visit(node : XML::Node)
+      # We only extract metadata from HTML nodes
+      if node.element?
+        add_node node 
+        if to = node["id"]?
+          add_id to, node
+        end
+        if classes = node["class"]?
+          classes.split(' ') { |to| add_class to, node }
+        end
+      end
+      # visit each child
+      node.children.each do | child |
+        visit child
+      end
     end
 
     # Find first tag by tag name and return
     # `Crystagiri::Tag` founded or a nil if not founded
     def at_tag(tag_name : String) : Crystagiri::Tag | Nil
-      where_tag(tag_name) { |tag| return tag }
+      if tags = @tags[tag_name]?
+        tags.each do |tag|
+          return Tag.new(tag).as Crystagiri::Tag
+        end
+      end
       return nil
     end
 
     # Find all nodes by tag name and yield
     # `Crystagiri::Tag` founded
     def where_tag(tag_name : String, &block) : Array(Tag)
-      return css(tag_name) { |tag| yield tag }
+      arr = [] of Crystagiri::Tag
+      if tags = @tags[tag_name]?
+        tags.each do |node|
+          tag = Tag.new(node).as Crystagiri::Tag
+          yield tag
+          arr << tag
+        end
+      end
+      return arr
     end
 
     # Find all nodes by classname and yield
     # `Crystagiri::Tag` founded
     def where_class(class_name : String, &block) : Array(Tag)
-      return css(".#{class_name}") { |tag| yield tag }
+      arr = [] of Crystagiri::Tag
+      if klasses = @classes[class_name]?
+        klasses.each do |node|
+          klass = Tag.new(node).as Crystagiri::Tag
+          yield klass
+          arr << klass
+        end
+      end
+      return arr
     end
 
     # Find a node by its id and return a
     # `Crystagiri::Tag` founded or a nil if not founded
     def at_id(id_name : String) : Crystagiri::Tag | Nil
-      css("##{id_name}") { |tag| return tag }
-      return nil
+      if node = @ids[id_name]?
+        return Tag.new(node).as Crystagiri::Tag
+      end
     end
 
     # Find all node corresponding to the css query and yield