slight performance improvement

7 files changed, 21 insertions, 20 deletions

diff --git a/lib/arel/extensions/class.rb b/lib/arel/extensions/class.rb
index fed2ef79c7..48d07a45f9 100644
--- a/lib/arel/extensions/class.rb
+++ b/lib/arel/extensions/class.rb
@@ -1,9 +1,11 @@
 class Class
-  def hash_on(delegatee)
+  def hash_on(*delegatees)
     define_method :eql? do |other|
       self == other
     end
     
-    delegate :hash, :to => delegatee
+    define_method :hash do
+      @hash ||= delegatees.map(&:hash).sum
+    end
   end
 end
\ No newline at end of file
diff --git a/lib/arel/primitives/attribute.rb b/lib/arel/primitives/attribute.rb
index bb951638e4..f3291b18da 100644
--- a/lib/arel/primitives/attribute.rb
+++ b/lib/arel/primitives/attribute.rb
@@ -46,8 +46,14 @@ module Arel
     end
 
     module Transformations
+      delegate :size, :to => :history
+      
       def self.included(klass)
-        klass.hash_on :name
+        klass.send :alias_method, :eql?, :==
+      end
+      
+      def hash
+        @hash ||= history.size + name.hash + relation.hash
       end
       
       def as(aliaz = nil)
diff --git a/lib/arel/relations/compound.rb b/lib/arel/relations/compound.rb
index 6f230c3f57..55b2bc80c7 100644
--- a/lib/arel/relations/compound.rb
+++ b/lib/arel/relations/compound.rb
@@ -10,12 +10,7 @@ module Arel
     def attributes
       @attributes ||= relation.attributes.collect { |a| a.bind(self) }
     end
-    
-    def selects
-      @selects ||= relation.selects.collect { |s| s.bind(self) }
-    end
-    
-    # XXX
+
     def relation_for(attribute)
       join? && relation.relation_for(attribute) || self[attribute] && self
     end
diff --git a/lib/arel/relations/order.rb b/lib/arel/relations/order.rb
index 662d3740df..2d72127722 100644
--- a/lib/arel/relations/order.rb
+++ b/lib/arel/relations/order.rb
@@ -6,14 +6,14 @@ module Arel
       @relation, @orderings = relation, orderings.collect { |o| o.bind(relation) }
     end
 
+    def orders
+      orderings + relation.orders
+    end
+    
     def ==(other)
       self.class  == other.class    and
       relation    == other.relation and
       orderings   == other.orderings
     end
-    
-    def orders
-      orderings + relation.orders
-    end
   end
 end
\ No newline at end of file
diff --git a/lib/arel/relations/selection.rb b/lib/arel/relations/selection.rb
index a37f51c9ec..c50db1c88a 100644
--- a/lib/arel/relations/selection.rb
+++ b/lib/arel/relations/selection.rb
@@ -9,7 +9,7 @@ module Arel
     end
 
     def selects
-      (relation.selects + [predicate]).collect { |p| p.bind(self) }
+      @selects ||= (relation.selects + [predicate]).collect { |p| p.bind(self) }
     end    
 
     def ==(other)
diff --git a/lib/arel/sessions/session.rb b/lib/arel/sessions/session.rb
index 9c61d0cba1..8b72fd1fe6 100644
--- a/lib/arel/sessions/session.rb
+++ b/lib/arel/sessions/session.rb
@@ -29,10 +29,9 @@ module Arel
       end
       
       def read(select)
-        @read ||= Hash.new do |hash, select|
+        (@read ||= Hash.new do |hash, select|
           hash[select] = select.call(select.engine.connection)
-        end
-        @read[select]
+        end)[select]
       end
       
       def update(update)
diff --git a/lib/arel/sql/christener.rb b/lib/arel/sql/christener.rb
index d0dbf47eaf..5883a75f41 100644
--- a/lib/arel/sql/christener.rb
+++ b/lib/arel/sql/christener.rb
@@ -3,11 +3,10 @@ module Arel
     class Christener
       def name_for(relation)
         @used_names ||= Hash.new(0)
-        @relation_names ||= Hash.new do |hash, relation|
+        (@relation_names ||= Hash.new do |hash, relation|
           @used_names[name = relation.name] += 1
           hash[relation] = name + (@used_names[name] > 1 ? "_#{@used_names[name]}" : '')
-        end
-        @relation_names[relation.table]
+        end)[relation.table]
       end
     end
   end