Add first/last methods to associations/named_scope. [#226 state:resolved]

Signed-off-by: Pratik Naik <pratiknaik@gmail.com>

2 files changed, 47 insertions, 2 deletions

diff --git a/activerecord/lib/active_record/associations/association_collection.rb b/activerecord/lib/active_record/associations/association_collection.rb
index 7e47bf7bdf..2d3750e107 100644
--- a/activerecord/lib/active_record/associations/association_collection.rb
+++ b/activerecord/lib/active_record/associations/association_collection.rb
@@ -48,6 +48,26 @@ module ActiveRecord
         end
       end
       
+      # fetch first using SQL if possible
+      def first(*args)
+        if fetch_first_or_last_using_find? args
+          find(:first, *args)
+        else
+          load_target unless loaded?
+          @target.first(*args)
+        end
+      end
+
+      # fetch last using SQL if possible
+      def last(*args)
+        if fetch_first_or_last_using_find? args
+          find(:last, *args)
+        else
+          load_target unless loaded?
+          @target.last(*args)
+        end
+      end
+
       def to_ary
         load_target
         @target.to_ary
@@ -330,7 +350,10 @@ module ActiveRecord
             raise ActiveRecord::RecordNotSaved, "You cannot call create unless the parent is saved"
           end
         end
-               
+
+        def fetch_first_or_last_using_find?(args)
+          args.first.kind_of?(Hash) || !(loaded? || @owner.new_record? || @reflection.options[:finder_sql] || !@target.blank? || args.first.kind_of?(Integer))
+        end
     end
   end
 end
diff --git a/activerecord/lib/active_record/named_scope.rb b/activerecord/lib/active_record/named_scope.rb
index 06edaed3d5..c7cf1731c1 100644
--- a/activerecord/lib/active_record/named_scope.rb
+++ b/activerecord/lib/active_record/named_scope.rb
@@ -102,7 +102,13 @@ module ActiveRecord
     
     class Scope
       attr_reader :proxy_scope, :proxy_options
-      [].methods.each { |m| delegate m, :to => :proxy_found unless m =~ /(^__|^nil\?|^send|^object_id$|class|extend|find|count|sum|average|maximum|minimum|paginate)/ }
+
+      [].methods.each do |m|
+        unless m =~ /(^__|^nil\?|^send|^object_id$|class|extend|find|count|sum|average|maximum|minimum|paginate|first|last)/
+          delegate m, :to => :proxy_found
+        end
+      end
+
       delegate :scopes, :with_scope, :to => :proxy_scope
 
       def initialize(proxy_scope, options, &block)
@@ -115,6 +121,22 @@ module ActiveRecord
         load_found; self
       end
 
+      def first(*args)
+        if args.first.kind_of?(Integer) || (@found && !args.first.kind_of?(Hash))
+          proxy_found.first(*args)
+        else
+          find(:first, *args)
+        end
+      end
+
+      def last(*args)
+        if args.first.kind_of?(Integer) || (@found && !args.first.kind_of?(Hash))
+          proxy_found.last(*args)
+        else
+          find(:last, *args)
+        end
+      end
+
       protected
       def proxy_found
         @found || load_found