Performance: javascript helper tweaks to speed up escaping and reduce object allocations when building options strings

3 files changed, 73 insertions, 60 deletions

diff --git a/actionpack/lib/action_view/helpers/javascript_helper.rb b/actionpack/lib/action_view/helpers/javascript_helper.rb
index 7404a251e4..31571de6c4 100644
--- a/actionpack/lib/action_view/helpers/javascript_helper.rb
+++ b/actionpack/lib/action_view/helpers/javascript_helper.rb
@@ -4,10 +4,10 @@ require 'action_view/helpers/prototype_helper'
 module ActionView
   module Helpers
     # Provides functionality for working with JavaScript in your views.
-    # 
+    #
     # == Ajax, controls and visual effects
-    # 
-    # * For information on using Ajax, see 
+    #
+    # * For information on using Ajax, see
     #   ActionView::Helpers::PrototypeHelper.
     # * For information on using controls and visual effects, see
     #   ActionView::Helpers::ScriptaculousHelper.
@@ -20,22 +20,22 @@ module ActionView
     # and ActionView::Helpers::ScriptaculousHelper), you must do one of the
     # following:
     #
-    # * Use <tt><%= javascript_include_tag :defaults %></tt> in the HEAD 
-    #   section of your page (recommended): This function will return 
+    # * Use <tt><%= javascript_include_tag :defaults %></tt> in the HEAD
+    #   section of your page (recommended): This function will return
     #   references to the JavaScript files created by the +rails+ command in
     #   your <tt>public/javascripts</tt> directory. Using it is recommended as
-    #   the browser can then cache the libraries instead of fetching all the 
+    #   the browser can then cache the libraries instead of fetching all the
     #   functions anew on every request.
-    # * Use <tt><%= javascript_include_tag 'prototype' %></tt>: As above, but 
+    # * Use <tt><%= javascript_include_tag 'prototype' %></tt>: As above, but
     #   will only include the Prototype core library, which means you are able
-    #   to use all basic AJAX functionality. For the Scriptaculous-based 
-    #   JavaScript helpers, like visual effects, autocompletion, drag and drop 
+    #   to use all basic AJAX functionality. For the Scriptaculous-based
+    #   JavaScript helpers, like visual effects, autocompletion, drag and drop
     #   and so on, you should use the method described above.
     # * Use <tt><%= define_javascript_functions %></tt>: this will copy all the
     #   JavaScript support functions within a single script block. Not
     #   recommended.
     #
-    # For documentation on +javascript_include_tag+ see 
+    # For documentation on +javascript_include_tag+ see
     # ActionView::Helpers::AssetTagHelper.
     module JavaScriptHelper
       unless const_defined? :JAVASCRIPT_PATH
@@ -43,13 +43,13 @@ module ActionView
       end
 
       include PrototypeHelper
-      
-      # Returns a link that will trigger a JavaScript +function+ using the 
+
+      # Returns a link that will trigger a JavaScript +function+ using the
       # onclick handler and return false after the fact.
       #
       # The +function+ argument can be omitted in favor of an +update_page+
       # block, which evaluates to a string when the template is rendered
-      # (instead of making an Ajax request first).      
+      # (instead of making an Ajax request first).
       #
       # Examples:
       #   link_to_function "Greeting", "alert('Hello world!')"
@@ -70,36 +70,31 @@ module ActionView
       #       <a href="#" id="more_link" onclick="try {
       #         $(&quot;details&quot;).visualEffect(&quot;toggle_blind&quot;);
       #         $(&quot;more_link&quot;).update(&quot;Show me less&quot;);
-      #       } 
-      #       catch (e) { 
-      #         alert('RJS error:\n\n' + e.toString()); 
+      #       }
+      #       catch (e) {
+      #         alert('RJS error:\n\n' + e.toString());
       #         alert('$(\&quot;details\&quot;).visualEffect(\&quot;toggle_blind\&quot;);
       #         \n$(\&quot;more_link\&quot;).update(\&quot;Show me less\&quot;);');
-      #         throw e 
+      #         throw e
       #       };
       #       return false;">Show me more</a>
       #
       def link_to_function(name, *args, &block)
-        html_options = args.extract_options!
-        function = args[0] || ''
-
-        html_options.symbolize_keys!
-        function = update_page(&block) if block_given?
-        content_tag(
-          "a", name, 
-          html_options.merge({ 
-            :href => html_options[:href] || "#", 
-            :onclick => (html_options[:onclick] ? "#{html_options[:onclick]}; " : "") + "#{function}; return false;" 
-          })
-        )
+        html_options = args.extract_options!.symbolize_keys!
+
+        function = block_given? ? update_page(&block) : args[0] || ''
+        onclick = "#{"#{html_options[:onclick]}; " if html_options[:onclick]}#{function}; return false;"
+        href = html_options[:href] || '#'
+
+        content_tag(:a, name, html_options.merge(:href => href, :onclick => onclick))
       end
-      
-      # Returns a button that'll trigger a JavaScript +function+ using the 
+
+      # Returns a button that'll trigger a JavaScript +function+ using the
       # onclick handler.
       #
       # The +function+ argument can be omitted in favor of an +update_page+
       # block, which evaluates to a string when the template is rendered
-      # (instead of making an Ajax request first).      
+      # (instead of making an Ajax request first).
       #
       # Examples:
       #   button_to_function "Greeting", "alert('Hello world!')"
@@ -111,45 +106,56 @@ module ActionView
       #     page[:details].visual_effect :toggle_slide
       #   end
       def button_to_function(name, *args, &block)
-        html_options = args.extract_options!
-        function = args[0] || ''
-
-        html_options.symbolize_keys!
-        function = update_page(&block) if block_given?
-        tag(:input, html_options.merge({ 
-          :type => "button", :value => name, 
-          :onclick => (html_options[:onclick] ? "#{html_options[:onclick]}; " : "") + "#{function};" 
-        }))
+        html_options = args.extract_options!.symbolize_keys!
+
+        function = block_given? ? update_page(&block) : args[0] || ''
+        onclick = "#{"#{html_options[:onclick]}; " if html_options[:onclick]}#{function};"
+
+        tag(:input, html_options.merge(:type => 'button', :value => name, :onclick => onclick))
       end
 
-      # Includes the Action Pack JavaScript libraries inside a single <script> 
+      # Includes the Action Pack JavaScript libraries inside a single <script>
       # tag. The function first includes prototype.js and then its core extensions,
       # (determined by filenames starting with "prototype").
       # Afterwards, any additional scripts will be included in undefined order.
       #
       # Note: The recommended approach is to copy the contents of
       # lib/action_view/helpers/javascripts/ into your application's
-      # public/javascripts/ directory, and use +javascript_include_tag+ to 
+      # public/javascripts/ directory, and use +javascript_include_tag+ to
       # create remote <script> links.
       def define_javascript_functions
         javascript = "<script type=\"#{Mime::JS}\">"
-        
-        # load prototype.js and its extensions first 
+
+        # load prototype.js and its extensions first
         prototype_libs = Dir.glob(File.join(JAVASCRIPT_PATH, 'prototype*')).sort.reverse
-        prototype_libs.each do |filename| 
+        prototype_libs.each do |filename|
           javascript << "\n" << IO.read(filename)
         end
-        
+
         # load other libraries
-        (Dir.glob(File.join(JAVASCRIPT_PATH, '*')) - prototype_libs).each do |filename| 
+        (Dir.glob(File.join(JAVASCRIPT_PATH, '*')) - prototype_libs).each do |filename|
           javascript << "\n" << IO.read(filename)
         end
         javascript << '</script>'
       end
 
+
+      JS_ESCAPE_MAP = {
+        '\\'    => '\\\\',
+        '</'    => '<\/',
+        "\r\n"  => '\n',
+        "\n"    => '\n',
+        "\r"    => '\n',
+        '"'     => '\\"',
+        "'"     => "\\'" }
+
       # Escape carrier returns and single and double quotes for JavaScript segments.
       def escape_javascript(javascript)
-        (javascript || '').gsub('\\','\0\0').gsub('</','<\/').gsub(/\r\n|\n|\r/, "\\n").gsub(/["']/) { |m| "\\#{m}" }
+        if javascript
+          javascript.gsub(/(\\|<\/|\r\n|[\n\r"'])/) { JS_ESCAPE_MAP[$1] }
+        else
+          ''
+        end
       end
 
       # Returns a JavaScript tag with the +content+ inside. Example:
@@ -163,7 +169,7 @@ module ActionView
       #   </script>
       #
       # +html_options+ may be a hash of attributes for the <script> tag. Example:
-      #   javascript_tag "alert('All is good')", :defer => 'defer' 
+      #   javascript_tag "alert('All is good')", :defer => 'defer'
       #   # => <script defer="defer" type="text/javascript">alert('All is good')</script>
       #
       # Instead of passing the content as an argument, you can also use a block
@@ -180,30 +186,37 @@ module ActionView
             content_or_options_with_block
           end
 
-        tag = content_tag("script", javascript_cdata_section(content), html_options.merge(:type => Mime::JS))
+        tag = content_tag(:script, javascript_cdata_section(content), html_options.merge(:type => Mime::JS))
 
-        block_given? ? concat(tag) : tag
+        if block_called_from_erb?(block)
+          concat(tag)
+        else
+          tag
+        end
       end
 
       def javascript_cdata_section(content) #:nodoc:
         "\n//#{cdata_section("\n#{content}\n//")}\n"
       end
-      
+
     protected
       def options_for_javascript(options)
-        '{' + options.map {|k, v| "#{k}:#{v}"}.sort.join(', ') + '}'
+        if options.empty?
+          '{}'
+        else
+          "{#{options.keys.map { |k| "#{k}:#{options[k]}" }.sort.join(', ')}}"
+        end
       end
-      
+
       def array_or_string_for_javascript(option)
-        js_option = if option.kind_of?(Array)
+        if option.kind_of?(Array)
           "['#{option.join('\',\'')}']"
         elsif !option.nil?
           "'#{option}'"
         end
-        js_option
       end
     end
-    
+
     JavascriptHelper = JavaScriptHelper unless const_defined? :JavascriptHelper
   end
 end
diff --git a/actionpack/lib/action_view/helpers/tag_helper.rb b/actionpack/lib/action_view/helpers/tag_helper.rb
index 649ec87a24..aeafd3906d 100644
--- a/actionpack/lib/action_view/helpers/tag_helper.rb
+++ b/actionpack/lib/action_view/helpers/tag_helper.rb
@@ -115,7 +115,7 @@ module ActionView
         # can't take an <% end %> later on, so we have to use <% ... %>
         # and implicitly concat.
         def block_called_from_erb?(block)
-          eval(BLOCK_CALLED_FROM_ERB, block)
+          block && eval(BLOCK_CALLED_FROM_ERB, block)
         end
 
         def content_tag_string(name, content, options, escape = true)
diff --git a/actionpack/lib/action_view/helpers/url_helper.rb b/actionpack/lib/action_view/helpers/url_helper.rb
index baecd304cd..d5b7255642 100644
--- a/actionpack/lib/action_view/helpers/url_helper.rb
+++ b/actionpack/lib/action_view/helpers/url_helper.rb
@@ -535,7 +535,7 @@ module ActionView
             when method
               "#{method_javascript_function(method, url, href)}return false;"
             when popup
-              popup_javascript_function(popup) + 'return false;'
+              "#{popup_javascript_function(popup)}return false;"
             else
               html_options["onclick"]
           end