Merge pull request #34 from ruby-concurrency/map-merge

Added a #merge method to the map classes.

Author: jdantonio

lib/ref/abstract_reference_key_map.rb

@@ -72,6 +72,13 @@ def to_a
       array
     end
 
+    # Returns a hash containing the names and values for the struct’s members.
+    def to_h
+      hash = {}
+      each{|k,v| hash[k] = v}
+      hash
+    end
+
     # Iterate through all the key/value pairs in the map that have not been reclaimed
     # by the garbage collector.
     def each
@@ -89,6 +96,18 @@ def clear
       end
     end
 
+    # Returns a new struct containing the contents of `other` and the contents
+    # of `self`. If no block is specified, the value for entries with duplicate
+    # keys will be that of `other`. Otherwise the value for each duplicate key
+    # is determined by calling the block with the key, its value in `self` and
+    # its value in `other`.
+    def merge(other_hash, &block)
+      to_h.merge(other_hash, &block).reduce(self.class.new) do |map, pair|
+        map[pair.first] = pair.last
+        map
+      end
+    end
+
     # Merge the values from another hash into this map.
     def merge!(other_hash)
       @lock.synchronize do
@@ -123,20 +142,20 @@ def inspect
 
     private
 
-      def ref_key (key)
-        ref = @references_to_keys_map[key.__id__]
-        if ref && ref.object
-          ref.referenced_object_id
-        else
-          nil
-        end
+    def ref_key (key)
+      ref = @references_to_keys_map[key.__id__]
+      if ref && ref.object
+        ref.referenced_object_id
+      else
+        nil
       end
+    end
 
-      def remove_reference_to(object_id)
-        @lock.synchronize do
-          @references_to_keys_map.delete(object_id)
-          @values.delete(object_id)
-        end
+    def remove_reference_to(object_id)
+      @lock.synchronize do
+        @references_to_keys_map.delete(object_id)
+        @values.delete(object_id)
       end
+    end
   end
 end

lib/ref/abstract_reference_value_map.rb

@@ -84,6 +84,13 @@ def to_a
       array
     end
 
+    # Returns a hash containing the names and values for the struct’s members.
+    def to_h
+      hash = {}
+      each{|k,v| hash[k] = v}
+      hash
+    end
+
     # Iterate through all the key/value pairs in the map that have not been reclaimed
     # by the garbage collector.
     def each
@@ -101,6 +108,18 @@ def clear
       end
     end
 
+    # Returns a new struct containing the contents of `other` and the contents
+    # of `self`. If no block is specified, the value for entries with duplicate
+    # keys will be that of `other`. Otherwise the value for each duplicate key
+    # is determined by calling the block with the key, its value in `self` and
+    # its value in `other`.
+    def merge(other_hash, &block)
+      to_h.merge(other_hash, &block).reduce(self.class.new) do |map, pair|
+        map[pair.first] = pair.last
+        map
+      end
+    end
+
     # Merge the values from another hash into this map.
     def merge!(other_hash)
       @lock.synchronize do
@@ -136,16 +155,16 @@ def inspect
 
     private
 
-      def remove_reference_to(object_id)
-        @lock.synchronize do
-          keys = @references_to_keys_map[object_id]
-          if keys
-            keys.each do |key|
-              @references.delete(key)
-            end
-            @references_to_keys_map.delete(object_id)
+    def remove_reference_to(object_id)
+      @lock.synchronize do
+        keys = @references_to_keys_map[object_id]
+        if keys
+          keys.each do |key|
+            @references.delete(key)
           end
+          @references_to_keys_map.delete(object_id)
         end
       end
+    end
   end
 end

spec/ref/soft_value_map_spec.rb

@@ -9,7 +9,7 @@
   let(:key_3)    { Object.new }
   let(:hash)     { map_class.new }
 
-  describe 'keeps entries with strong references' do
+  context 'keeps entries with strong references' do
     specify do
       Ref::Mock.use do
         hash[key_1] = "value 1"
@@ -20,7 +20,7 @@
     end
   end
 
-  describe 'removes entries that have been garbage collected' do
+  context 'removes entries that have been garbage collected' do
     specify do
       Ref::Mock.use do
         hash[key_1] = value_1
@@ -34,7 +34,7 @@
     end
   end
 
-  describe 'can clear the map' do
+  context 'can clear the map' do
     specify do
       Ref::Mock.use do
         hash[key_1] = value_1
@@ -46,7 +46,7 @@
     end
   end
 
-  describe 'can delete entries' do
+  context 'can delete entries' do
     specify do
       Ref::Mock.use do
         hash[key_1] = value_1
@@ -59,7 +59,7 @@
     end
   end
 
-  describe 'can merge in another hash' do
+  context 'can merge in another hash' do
     specify do
       Ref::Mock.use do
         hash[key_1] = value_1
@@ -78,7 +78,7 @@
     end
   end
 
-  describe 'can get all keys' do
+  context 'can get all keys' do
     specify do
       Ref::Mock.use do
         hash[key_1] = value_1
@@ -91,7 +91,7 @@
     end
   end
 
-  describe 'can turn into an array' do
+  context 'can turn into an array' do
     specify do
       Ref::Mock.use do
         hash[key_1] = value_1
@@ -105,7 +105,21 @@
     end
   end
 
-  describe 'can interate over all entries' do
+  context 'can turn into a hash' do
+    specify do
+      Ref::Mock.use do
+        hash[key_1] = value_1
+        hash[key_2] = value_2
+        hash[key_3] = value_3
+        order = lambda{|a,b| a.last <=> b.last}
+        expect({key_1 => "value 1", key_2 => "value 2", key_3 => "value 3"}.sort(&order)).to eq hash.to_h.sort(&order)
+        Ref::Mock.gc(key_2)
+        expect({key_1 => "value 1", key_3 => "value 3"}.sort(&order)).to eq hash.to_h.sort(&order)
+      end
+    end
+  end
+
+  context 'can interate over all entries' do
     specify do
       Ref::Mock.use do
         hash[key_1] = value_1
@@ -126,7 +140,7 @@
     end
   end
 
-  describe 'size' do
+  context 'size' do
     specify do
       Ref::Mock.use do
         hash = map_class.new
@@ -144,12 +158,55 @@
     end
   end
 
-  describe 'inspect' do
+  context 'inspect' do
     specify do
       Ref::Mock.use do
         hash[Object.new] = "value 1"
         expect(hash.inspect).to_not be_nil
       end
     end
   end
+
+  context '#merge' do
+
+    let(:new_value){ Object.new }
+    let(:values){ {key_1 => value_1, key_2 => value_2, key_3 => value_3} }
+    let(:this) do
+      values.each{|k, v| hash[k] = v }
+      hash
+    end
+    let(:other){ {key_3 => new_value} }
+
+    it 'updates all members with the new values from a given hash' do
+      expect(this.merge(other)[key_3]).to eq new_value
+    end
+
+    it 'calls the given block for each key in `other`' do
+      actual = 0
+      this.merge(key_2 => 'yes', key_3 => 'no'){|member, thisval, otherval| actual += 1; Object.new }
+      expect(actual).to eq 2
+    end
+
+    it 'retains the value for all members without values in the given hash' do
+      expect(this.merge(other)[key_1]).to eq value_1
+    end
+
+    it 'adds members not in the original hash' do
+      new_key = Object.new
+      new_value = 'life, the universe, and everything'
+      expect(this.merge(new_key => new_value)[new_key]).to eq new_value
+    end
+
+    it 'returns a deep copy when merging an empty hash' do
+      other = this.merge({})
+      values.each do |key, value|
+        expect(other[key]).to eq value
+      end
+    end
+
+    it 'returns a new object' do
+      expect(this.merge(other).object_id).to_not eq this.object_id
+      expect(this.merge(other).object_id).to_not eq other.object_id
+    end
+  end
 end