Move escape_once logic to ERB::Util, where it belongs to

All the logic is based on the HTML_ESCAPE constant available in
ERB::Util, so it seems more logic to have the entire method there and
just delegate the helper to use it.

4 files changed, 32 insertions, 1 deletions

diff --git a/actionpack/lib/action_view/helpers/tag_helper.rb b/actionpack/lib/action_view/helpers/tag_helper.rb
index d7a2651bad..ecd26891d6 100644
--- a/actionpack/lib/action_view/helpers/tag_helper.rb
+++ b/actionpack/lib/action_view/helpers/tag_helper.rb
@@ -118,7 +118,7 @@ module ActionView
       #   escape_once("<< Accept & Checkout")
       #   # => "<< Accept & Checkout"
       def escape_once(html)
-        html.to_s.gsub(/[\"><]|&(?!([a-zA-Z]+|(#\d+));)/) { |special| ERB::Util::HTML_ESCAPE[special] }
+        ERB::Util.html_escape_once(html)
       end
 
       private
diff --git a/actionpack/test/template/erb_util_test.rb b/actionpack/test/template/erb_util_test.rb
index eba2ef64e0..ca2710e9b3 100644
--- a/actionpack/test/template/erb_util_test.rb
+++ b/actionpack/test/template/erb_util_test.rb
@@ -44,4 +44,18 @@ class ErbUtilTest < ActiveSupport::TestCase
       assert_equal chr, html_escape(chr)
     end
   end
+
+  def test_html_escape_once
+    assert_equal '1 &lt; 2 &amp; 3', html_escape_once('1 < 2 &amp; 3')
+  end
+
+  def test_html_escape_once_returns_unsafe_strings_when_passed_unsafe_strings
+    value = html_escape_once('1 < 2 &amp; 3')
+    assert !value.html_safe?
+  end
+
+  def test_html_escape_once_returns_safe_strings_when_passed_safe_strings
+    value = html_escape_once('1 < 2 &amp; 3'.html_safe)
+    assert value.html_safe?
+  end
 end
diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index 5df3ec406f..ad9a12fc9b 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,5 +1,7 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*    Add html_escape_once to ERB::Util, and delegate escape_once tag helper to it. *Carlos Antonio da Silva*
+
 *    Remove ActiveSupport::TestCase#pending method, use `skip` instead. *Carlos Antonio da Silva*
 
 *    Deprecates the compatibility method Module#local_constant_names,
diff --git a/activesupport/lib/active_support/core_ext/string/output_safety.rb b/activesupport/lib/active_support/core_ext/string/output_safety.rb
index 73aa7dd89a..a8d51abbb5 100644
--- a/activesupport/lib/active_support/core_ext/string/output_safety.rb
+++ b/activesupport/lib/active_support/core_ext/string/output_safety.rb
@@ -33,6 +33,21 @@ class ERB
     singleton_class.send(:remove_method, :html_escape)
     module_function :html_escape
 
+    # Returns an escaped version of +html+ without affecting existing escaped entities.
+    #
+    # ==== Examples
+    #   html_escape_once("1 < 2 &amp; 3")
+    #   # => "1 &lt; 2 &amp; 3"
+    #
+    #   html_escape_once("&lt;&lt; Accept & Checkout")
+    #   # => "&lt;&lt; Accept &amp; Checkout"
+    def html_escape_once(s)
+      result = s.to_s.gsub(/[\"><]|&(?!([a-zA-Z]+|(#\d+));)/) { |special| HTML_ESCAPE[special] }
+      s.html_safe? ? result.html_safe : result
+    end
+
+    module_function :html_escape_once
+
     # A utility method for escaping HTML entities in JSON strings
     # using \uXXXX JavaScript escape sequences for string literals:
     #