Added ability to check the size of a reference map

Author: ianunruh

lib/ref/abstract_reference_key_map.rb

@@ -88,6 +88,20 @@ def merge!(other_hash)
       end
     end
 
+    # The number of entries in the map
+    def size
+      @references_to_keys_map.count do |rkey, ref|
+        ref.object
+      end
+    end
+
+    alias_method :length, :size
+
+    # True if there are entries that exist in the map
+    def empty?
+      size == 0
+    end
+
     def inspect
       live_entries = {}
       each do |key, value|

lib/ref/abstract_reference_value_map.rb

@@ -102,6 +102,20 @@ def merge!(other_hash)
       end
     end
 
+    # The number of entries in the map
+    def size
+      @references.count do |key, ref|
+        ref.object
+      end
+    end
+
+    alias_method :length, :size
+
+    # True if there are entries that exist in the map
+    def empty?
+      size == 0
+    end
+
     def inspect
       live_entries = {}
       each do |key, value|

test/reference_key_map_behavior.rb

@@ -145,6 +145,21 @@ def test_can_iterate_over_all_entries
     end
   end
 
+  def test_size
+    Ref::Mock.use do
+      hash = map_class.new
+      assert_true hash.empty?
+      assert_equal 0, hash.size
+      key_2 = Object.new
+      hash[key_1] = "value 1"
+      assert_false hash.empty?
+      assert_equal 2, hash.size
+      Ref::Mock.gc(key_2)
+      assert_false hash.empty?
+      assert_equal 1, hash.size
+    end
+  end
+
   def test_inspect
     Ref::Mock.use do
       hash = map_class.new

test/reference_value_map_behavior.rb

@@ -125,6 +125,23 @@ def test_can_iterate_over_all_entries
     end
   end
 
+  def test_size
+    Ref::Mock.use do
+      hash = map_class.new
+      assert_true hash.empty?
+      assert_equal 0, hash.size
+      value_1 = "value 1"
+      value_2 = "value 2"
+      hash["key 1"] = value_1
+      hash["key 2"] = value_2
+      assert_false hash.empty?
+      assert_equal 2, hash.size
+      Ref::Mock.gc(value_2)
+      assert_false hash.empty?
+      assert_equal 1, hash.size
+    end
+  end
+
   def test_inspect
     Ref::Mock.use do
       hash = map_class.new