Use accumulator on raw_html (#588)

* Use accumulator on raw_html

* Use proper list

lib/floki/raw_html.ex

@@ -36,6 +36,7 @@ defmodule Floki.RawHTML do
 
   def raw_html(html_tree, opts) do
     opts = Keyword.validate!(opts, encode: use_default_encoder?(), pretty: false)
+    html_tree = List.wrap(html_tree)
 
     encoder =
       case opts[:encode] do
@@ -51,53 +52,36 @@ defmodule Floki.RawHTML do
 
     self_closing_tags = self_closing_tags()
 
-    IO.iodata_to_binary(build_raw_html(html_tree, [], encoder, padding, self_closing_tags))
+    html_tree
+    |> build_raw_html([], encoder, padding, self_closing_tags)
+    |> Enum.reverse()
+    |> IO.iodata_to_binary()
   end
 
-  defp build_raw_html([], html, _encoder, _padding, _self_closing_tags), do: html
+  defp build_raw_html([], acc, _encoder, _padding, _self_closing_tags), do: acc
 
-  defp build_raw_html(string, _html, encoder, padding, _self_closing_tags)
+  defp build_raw_html([string | tail], acc, encoder, padding, self_closing_tags)
        when is_binary(string) do
-    leftpad_content(padding, encoder.(string))
+    content = leftpad_content(padding, encoder.(string))
+    acc = [content | acc]
+    build_raw_html(tail, acc, encoder, padding, self_closing_tags)
   end
 
-  defp build_raw_html(tuple, html, encoder, padding, self_closing_tags) when is_tuple(tuple),
-    do: build_raw_html([tuple], html, encoder, padding, self_closing_tags)
-
-  defp build_raw_html([string | tail], html, encoder, padding, self_closing_tags)
-       when is_binary(string) do
-    build_raw_html(
-      tail,
-      [html, leftpad_content(padding, encoder.(string))],
-      encoder,
-      padding,
-      self_closing_tags
-    )
+  defp build_raw_html([{:comment, comment} | tail], acc, encoder, padding, self_closing_tags) do
+    content = [leftpad(padding), "<!--", comment, "-->"]
+    acc = [content | acc]
+    build_raw_html(tail, acc, encoder, padding, self_closing_tags)
   end
 
-  defp build_raw_html([{:comment, comment} | tail], html, encoder, padding, self_closing_tags),
-    do:
-      build_raw_html(
-        tail,
-        [html, leftpad(padding), "<!--", comment, "-->"],
-        encoder,
-        padding,
-        self_closing_tags
-      )
-
-  defp build_raw_html([{:pi, tag, attrs} | tail], html, encoder, padding, self_closing_tags) do
-    build_raw_html(
-      tail,
-      [html, leftpad(padding), "<?", tag, tag_attrs(attrs, encoder), "?>"],
-      encoder,
-      padding,
-      self_closing_tags
-    )
+  defp build_raw_html([{:pi, tag, attrs} | tail], acc, encoder, padding, self_closing_tags) do
+    content = [leftpad(padding), "<?", tag, tag_attrs(attrs, encoder), "?>"]
+    acc = [content | acc]
+    build_raw_html(tail, acc, encoder, padding, self_closing_tags)
   end
 
   defp build_raw_html(
          [{:doctype, type, public, system} | tail],
-         html,
+         acc,
          encoder,
          padding,
          self_closing_tags
@@ -109,23 +93,40 @@ defmodule Floki.RawHTML do
         {public, system} -> [" PUBLIC \"", public, "\" \"", system | "\""]
       end
 
-    build_raw_html(
-      tail,
-      [html, leftpad(padding), "<!DOCTYPE ", type, attr | ">"],
-      encoder,
-      padding,
-      self_closing_tags
-    )
+    content = [leftpad(padding), "<!DOCTYPE ", type, attr, ">"]
+    acc = [content | acc]
+    build_raw_html(tail, acc, encoder, padding, self_closing_tags)
   end
 
-  defp build_raw_html([{type, attrs, children} | tail], html, encoder, padding, self_closing_tags) do
-    build_raw_html(
-      tail,
-      [html | tag_for(type, attrs, children, encoder, padding, self_closing_tags)],
-      encoder,
-      padding,
-      self_closing_tags
-    )
+  defp build_raw_html([{type, attrs, children} | tail], acc, encoder, padding, self_closing_tags) do
+    encoder =
+      case type do
+        "script" -> @no_encoder
+        "style" -> @no_encoder
+        "title" -> @no_encoder
+        _ -> encoder
+      end
+
+    open_tag_content = [
+      tag_with_attrs(type, attrs, children, padding, encoder, self_closing_tags),
+      line_ending(padding)
+    ]
+
+    acc = [open_tag_content | acc]
+
+    acc =
+      case children do
+        [] ->
+          acc
+
+        _ ->
+          children = List.wrap(children)
+          build_raw_html(children, acc, encoder, pad_increase(padding), self_closing_tags)
+      end
+
+    close_tag_content = close_end_tag(type, children, padding, self_closing_tags)
+    acc = [close_tag_content | acc]
+    build_raw_html(tail, acc, encoder, padding, self_closing_tags)
   end
 
   defp tag_attrs(attr_list, encoder) do
@@ -171,29 +172,6 @@ defmodule Floki.RawHTML do
 
   defp build_attrs(attr, _encoder), do: [?\s, attr]
 
-  defp tag_for(type, attrs, children, encoder, padding, self_closing_tags) do
-    encoder =
-      case type do
-        "script" -> @no_encoder
-        "style" -> @no_encoder
-        "title" -> @no_encoder
-        _ -> encoder
-      end
-
-    children_content =
-      case children do
-        [] -> ""
-        _ -> build_raw_html(children, "", encoder, pad_increase(padding), self_closing_tags)
-      end
-
-    [
-      tag_with_attrs(type, attrs, children, padding, encoder, self_closing_tags),
-      line_ending(padding),
-      children_content,
-      close_end_tag(type, children, padding, self_closing_tags)
-    ]
-  end
-
   defp use_default_encoder? do
     Application.get_env(:floki, :encode_raw_html, true)
   end