Cache pluralizations in interpolations for speed

lib/paperclip.rb

@@ -35,6 +35,7 @@ require 'paperclip/geometry'
 require 'paperclip/processor'
 require 'paperclip/tempfile'
 require 'paperclip/thumbnail'
+require 'paperclip/interpolations/plural_cache'
 require 'paperclip/interpolations'
 require 'paperclip/tempfile_factory'
 require 'paperclip/style'

lib/paperclip/interpolations.rb

@@ -36,6 +36,10 @@ module Paperclip
       end
     end
 
+    def self.plural_cache
+      @plural_cache ||= PluralCache.new
+    end
+
     # Returns the filename, the same way as ":basename.:extension" would.
     def filename attachment, style_name
       [ basename(attachment, style_name), extension(attachment, style_name) ].reject(&:blank?).join(".")
@@ -81,7 +85,7 @@ module Paperclip
     # all class names. Calling #class will return the expected class.
     def class attachment = nil, style_name = nil
       return super() if attachment.nil? && style_name.nil?
-      attachment.instance.class.to_s.underscore.pluralize
+      plural_cache.underscore_and_pluralize(attachment.instance.class.to_s)
     end
 
     # Returns the basename of the file. e.g. "file" for "file.jpg"
@@ -169,7 +173,7 @@ module Paperclip
     # Returns the pluralized form of the attachment name. e.g.
     # "avatars" for an attachment of :avatar
     def attachment attachment, style_name
-      attachment.name.to_s.downcase.pluralize
+      plural_cache.pluralize(attachment.name.to_s.downcase)
     end
 
     # Returns the style, or the default style if nil is supplied.

lib/paperclip/interpolations/plural_cache.rb

+module Paperclip
+  module Interpolations
+    class PluralCache
+      def initialize
+        @cache = {}
+      end
+
+      def pluralize(word)
+        @cache[word] ||= word.pluralize
+      end
+
+      def underscore_and_pluralize(word)
+        @cache[word] ||= word.underscore.pluralize
+      end
+    end
+  end
+end

test/plural_cache_test.rb

+require './test/helper'
+
+class PluralCacheTest < Test::Unit::TestCase
+  should 'cache pluralizations' do
+    cache = Paperclip::Interpolations::PluralCache.new
+    word = "box"
+
+    word.expects(:pluralize).returns("boxes").once
+
+    cache.pluralize(word)
+    cache.pluralize(word)
+  end
+
+  should 'cache pluralizations and underscores' do
+    cache = Paperclip::Interpolations::PluralCache.new
+    word = "BigBox"
+
+    word.expects(:pluralize).returns(word).once
+    word.expects(:underscore).returns(word).once
+
+    cache.underscore_and_pluralize(word)
+    cache.underscore_and_pluralize(word)
+  end
+
+  should 'pluralize words' do
+    cache = Paperclip::Interpolations::PluralCache.new
+    word = "box"
+    assert_equal "boxes", cache.pluralize(word)
+  end
+
+  should 'pluralize and underscore words' do
+    cache = Paperclip::Interpolations::PluralCache.new
+    word = "BigBox"
+    assert_equal "big_boxes", cache.underscore_and_pluralize(word)
+  end
+end