From 23078698b3e1ac2066331e9c8fd4d51077be6866 Mon Sep 17 00:00:00 2001
From: Chris Kampmeier <chris@kampers.net>
Date: Sat, 29 Nov 2008 05:20:31 -0800
Subject: [PATCH] Add #hash and #eql? to ActiveSupport::Multibyte::Chars so you can use multibyte strings as hash keys without Ruby 1.9

---
 .../lib/active_support/multibyte/chars.rb          |   21 ++++++++++++++++
 activesupport/test/multibyte_chars_test.rb         |   25 ++++++++++++++++----
 2 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/activesupport/lib/active_support/multibyte/chars.rb b/activesupport/lib/active_support/multibyte/chars.rb
index be9c6d3..38d2e9d 100644
--- a/activesupport/lib/active_support/multibyte/chars.rb
+++ b/activesupport/lib/active_support/multibyte/chars.rb
@@ -165,6 +165,27 @@ module ActiveSupport #:nodoc:
         translate_offset(@wrapped_string =~ other)
       end
 
+      if RUBY_VERSION < '1.9'
+        # Returns a Fixnum unique to the string's length and content. This is
+        # used during hash insertion and comparison.
+        #
+        # Example:
+        #   'Café périferôl'.mb_chars.hash  # => 62351556
+        def hash
+          @wrapped_string.hash
+        end
+
+        # Returns +true+ if the Chars object has the same length and content as
+        # _other_, or +false+ otherwise. It accepts any object that implements +to_s+.
+        #
+        # Example:
+        #   'Café'.mb_chars.eql?('Café'.mb_chars)  # => true
+        #   'Café'.mb_chars.eql?('Cafe'.mb_chars)  # => false
+        def eql?(other)
+          @wrapped_string.eql?(other.to_s)
+        end
+      end
+
       # Works just like <tt>String#split</tt>, with the exception that the items in the resulting list are Chars
       # instances instead of String. This makes chaining methods easier.
       #
diff --git a/activesupport/test/multibyte_chars_test.rb b/activesupport/test/multibyte_chars_test.rb
index ca2af9b..0ce58c0 100644
--- a/activesupport/test/multibyte_chars_test.rb
+++ b/activesupport/test/multibyte_chars_test.rb
@@ -152,11 +152,26 @@ class MultibyteCharsUTF8BehaviourTest < Test::Unit::TestCase
   def test_identity
     assert_equal @chars, @chars
     assert @chars.eql?(@chars)
-    if RUBY_VERSION <= '1.9'
-      assert !@chars.eql?(UNICODE_STRING)
-    else
-      assert @chars.eql?(UNICODE_STRING)
-    end
+    assert @chars.eql?(UNICODE_STRING)
+    assert !@chars.eql?('other'.mb_chars)
+    assert !@chars.eql?('other')
+  end
+
+  def test_should_be_usable_as_hash_keys
+    @same_chars = UNICODE_STRING.dup.mb_chars
+    assert_equal({@chars => true}, {@same_chars => true})
+    assert_not_equal({@chars => true}, {'other'.mb_chars => true})
+    assert_equal({@chars => true}.merge(@same_chars => false), {@chars => false})
+    assert_equal({@chars => true}[@same_chars], true)
+  end
+
+  def test_hash_is_deferred_to_the_wrapped_string
+    assert_equal @chars.hash, UNICODE_STRING.hash
+  end
+
+  def test_hash_equality
+    assert_equal @chars.hash, UNICODE_STRING.mb_chars.hash
+    assert_not_equal @chars.hash, 'other'.mb_chars.hash
   end
 
   def test_string_methods_are_chainable
-- 
1.6.0.4