Only apply textarea fix to textareas; refactor

Textareas are the only preserved tag that is editable, so we don't need to
recode the newline for <pre> or <code> tags. With this and the last few
preceding commits we bring Haml 4.x's performance nearly back in line with Haml
3.1.4.

Haml 3.1.4:

                           user     system      total        real
compiled haml pretty   0.330000   0.000000   0.330000 (  0.332720)
compiled haml ugly     0.180000   0.000000   0.180000 (  0.173543)
cached haml pretty     0.740000   0.000000   0.740000 (  0.740294)
cached haml ugly       0.490000   0.000000   0.490000 (  0.497688)

Haml 3.1.8:

                           user     system      total        real
compiled haml pretty   0.600000   0.000000   0.600000 (  0.605575)
compiled haml ugly     0.210000   0.000000   0.210000 (  0.210508)
cached haml pretty     1.240000   0.010000   1.250000 (  1.256737)
cached haml ugly       0.520000   0.000000   0.520000 (  0.527566)

Haml 4.0.0:

                           user     system      total        real
compiled haml pretty   0.720000   0.000000   0.720000 (  0.754891)
compiled haml ugly     0.300000   0.000000   0.300000 (  0.296439)
cached haml pretty     1.300000   0.000000   1.300000 (  1.301510)
cached haml ugly       0.570000   0.000000   0.570000 (  0.578155)

This commit:

                           user     system      total        real
compiled haml pretty   0.430000   0.010000   0.440000 (  0.429153)
compiled haml ugly     0.220000   0.000000   0.220000 (  0.220758)
cached haml pretty     0.810000   0.000000   0.810000 (  0.809804)
cached haml ugly       0.510000   0.000000   0.510000 (  0.516821)

lib/haml/buffer.rb

@@ -156,9 +156,7 @@ module Haml
       <% end  %>
 
       <% if  ugly %>
-        if toplevel?
-          result = Haml::Helpers.fix_preserved_whitespace(result, nil, options)
-        end
+        fix_textareas!(result, nil) if toplevel? && result.include?('<textarea')
         return result
       <% else  %>
         <% if  !(in_tag && preserve_tag && !nuke_inner_whitespace) %>
@@ -186,9 +184,7 @@ module Haml
           <% if  in_tag && !nuke_inner_whitespace %> result = tabs(tabulation) + result <% end %>
         end
 
-        if toplevel?
-          result = Haml::Helpers.fix_preserved_whitespace(result, tabs(tabulation), options)
-        end
+        fix_textareas!(result, tabs(tabulation)) if toplevel? && result.include?('<textarea')
 
         <% if  in_tag && !nuke_inner_whitespace %>
           result = "\\n\#{result}\\n\#{tabs(tabulation-1)}"
@@ -265,6 +261,29 @@ RUBY
 
     private
 
+    # Works like #{find_and_preserve}, but allows the first newline after a
+    # preserved opening tag to remain unencoded, and then outdents the content.
+    # This change was motivated primarily by the change in Rails 3.2.3 to emit
+    # a newline after textarea helpers.
+    #
+    # @param input [String] The text to process
+    # @param tabs [String] The tabs provided by the Haml::Buffer
+    # @param options [Hash] The options hash provided by the Haml::Buffer
+    # @since Haml 4.0.1
+    # @private
+    def fix_textareas!(input, tabs)
+      pattern = /([ ]*)<(textarea)([^>]*)>(\n|&#x000A;)(.*?)(<\/\2>)/im
+      input.gsub!(pattern) do |s|
+        match = pattern.match(s)
+        content = match[5]
+        unless tabs.nil?
+          content.sub!(match[1].to_s, '')
+          content.sub!(tabs, '')
+        end
+        "#{match[1]}<#{match[2]}#{match[3]}>\n#{content}</#{match[2]}>"
+      end
+    end
+
     if RUBY_VERSION < "1.9"
       def new_encoded_string
         ""

lib/haml/helpers.rb

@@ -113,33 +113,6 @@ MESSAGE
       end
     end
 
-    # Works like #{find_and_preserve}, but allows the first newline after a
-    # preserved opening tag to remain unencoded, and then outdents the content.
-    # This change was motivated primarily by the change in Rails 3.2.3 to emit
-    # a newline after textarea helpers.
-    #
-    # There's no reason this should be part of the public API provided by Haml
-    # and is here only for uniformity with the other helpers' locations. In a
-    # future version of Haml this will likely be moved into Haml::Buffer, so
-    # use it at your own risk.
-    #
-    # @param input [String] The text to process
-    # @param tabs [String] The tabs provided by the Haml::Buffer
-    # @param options [Hash] The options hash provided by the Haml::Buffer
-    # @since Haml 4.0.1
-    # @private
-    def fix_preserved_whitespace(input, tabs, options)
-      input.gsub(options[:retab_pattern]) do |s|
-        match = options[:retab_pattern].match(s)
-        content = match[5]
-        unless tabs.nil?
-          content.sub!(match[1].to_s, '')
-          content.sub!(tabs, '')
-        end
-        "#{match[1]}<#{match[2]}#{match[3]}>\n#{content}</#{match[2]}>"
-      end
-    end
-
     # Takes any string, finds all the newlines, and converts them to
     # HTML entities so they'll render correctly in
     # whitespace-sensitive tags without screwing up the indentation.

lib/haml/options.rb

@@ -261,9 +261,7 @@ module Haml
     #
     # @return [{Symbol => Object}] The options hash
     def for_buffer
-      options_for_buffer = {}
-      options_for_buffer[:retab_pattern] = /([ ]*)<(#{preserve.map(&Regexp.method(:escape)).join('|')})([^>]*)>(\n|&#x000A;)(.*?)(<\/\2>)/im
-      self.class.buffer_option_keys.inject(options_for_buffer) do |hash, key|
+      self.class.buffer_option_keys.inject({}) do |hash, key|
         hash[key] = send(key)
         hash
       end