1 files changed, 40 insertions, 101 deletions

diff --git a/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb b/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
index e2ce9aefcf..028630977d 100644
--- a/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
+++ b/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
@@ -1,134 +1,73 @@
 module ActiveRecord
   # = Active Record Has And Belongs To Many Association
   module Associations
-    class HasAndBelongsToManyAssociation < AssociationCollection #:nodoc:
-      def create(attributes = {})
-        create_record(attributes) { |record| insert_record(record) }
-      end
+    class HasAndBelongsToManyAssociation < CollectionAssociation #:nodoc:
+      attr_reader :join_table
 
-      def create!(attributes = {})
-        create_record(attributes) { |record| insert_record(record, true) }
+      def initialize(owner, reflection)
+        @join_table = Arel::Table.new(reflection.options[:join_table])
+        super
       end
 
-      def columns
-        @reflection.columns(@reflection.options[:join_table], "#{@reflection.options[:join_table]} Columns")
-      end
+      def insert_record(record, validate = true)
+        return if record.new_record? && !record.save(:validate => validate)
+
+        if options[:insert_sql]
+          owner.connection.insert(interpolate(options[:insert_sql], record))
+        else
+          stmt = join_table.compile_insert(
+            join_table[reflection.foreign_key]             => owner.id,
+            join_table[reflection.association_foreign_key] => record.id
+          )
 
-      def reset_column_information
-        @reflection.reset_column_information
+          owner.connection.insert stmt.to_sql
+        end
+
+        record
       end
 
-      def has_primary_key?
-        @has_primary_key ||= @owner.connection.supports_primary_key? && @owner.connection.primary_key(@reflection.options[:join_table])
+      def association_scope
+        super.joins(construct_joins)
       end
 
-      protected
-        def construct_find_options!(options)
-          options[:joins]      = Arel::SqlLiteral.new(@scope[:find][:joins])
-          options[:readonly]   = finding_with_ambiguous_select?(options[:select] || @reflection.options[:select])
-          options[:select]   ||= (@reflection.options[:select] || Arel::SqlLiteral.new('*'))
-        end
+      private
 
         def count_records
           load_target.size
         end
 
-        def insert_record(record, force = true, validate = true)
-          if record.new_record?
-            if force
-              record.save!
-            else
-              return false unless record.save(:validate => validate)
-            end
-          end
-
-          if @reflection.options[:insert_sql]
-            @owner.connection.insert(interpolate_sql(@reflection.options[:insert_sql], record))
+        def delete_records(records, method)
+          if sql = options[:delete_sql]
+            records.each { |record| owner.connection.delete(interpolate(sql, record)) }
           else
-            relation   = Arel::Table.new(@reflection.options[:join_table])
-            timestamps = record_timestamp_columns(record)
-            timezone   = record.send(:current_time_from_proper_timezone) if timestamps.any?
-
-            attributes = columns.map do |column|
-              name = column.name
-              value = case name.to_s
-                when @reflection.primary_key_name.to_s
-                  @owner.id
-                when @reflection.association_foreign_key.to_s
-                  record.id
-                when *timestamps
-                  timezone
-                else
-                  @owner.send(:quote_value, record[name], column) if record.has_attribute?(name)
-              end
-              [relation[name], value] unless value.nil?
-            end
-
-            stmt = relation.compile_insert Hash[attributes]
-            @owner.connection.insert stmt.to_sql
-          end
-
-          true
-        end
-
-        def delete_records(records)
-          if sql = @reflection.options[:delete_sql]
-            records.each { |record| @owner.connection.delete(interpolate_sql(sql, record)) }
-          else
-            relation = Arel::Table.new(@reflection.options[:join_table])
-            stmt = relation.where(relation[@reflection.primary_key_name].eq(@owner.id).
-              and(relation[@reflection.association_foreign_key].in(records.map { |x| x.id }.compact))
+            relation = join_table
+            stmt = relation.where(relation[reflection.foreign_key].eq(owner.id).
+              and(relation[reflection.association_foreign_key].in(records.map { |x| x.id }.compact))
             ).compile_delete
-            @owner.connection.delete stmt.to_sql
+            owner.connection.delete stmt.to_sql
           end
         end
 
         def construct_joins
-          "INNER JOIN #{@owner.connection.quote_table_name @reflection.options[:join_table]} ON #{@reflection.quoted_table_name}.#{@reflection.klass.primary_key} = #{@owner.connection.quote_table_name @reflection.options[:join_table]}.#{@reflection.association_foreign_key}"
-        end
+          right = join_table
+          left  = reflection.klass.arel_table
 
-        def construct_conditions
-          sql = "#{@owner.connection.quote_table_name @reflection.options[:join_table]}.#{@reflection.primary_key_name} = #{owner_quoted_id} "
-          sql << " AND (#{conditions})" if conditions
-          sql
-        end
+          condition = left[reflection.klass.primary_key].eq(
+            right[reflection.association_foreign_key])
 
-        def construct_find_scope
-          {
-            :conditions => construct_conditions,
-            :joins      => construct_joins,
-            :readonly   => false,
-            :order      => @reflection.options[:order],
-            :include    => @reflection.options[:include],
-            :limit      => @reflection.options[:limit]
-          }
+          right.create_join(right, right.create_on(condition))
         end
 
-        # Join tables with additional columns on top of the two foreign keys must be considered
-        # ambiguous unless a select clause has been explicitly defined. Otherwise you can get
-        # broken records back, if, for example, the join column also has an id column. This will
-        # then overwrite the id column of the records coming back.
-        def finding_with_ambiguous_select?(select_clause)
-          !select_clause && columns.size != 2
+        def construct_owner_conditions
+          super(join_table)
         end
 
-      private
-        def create_record(attributes, &block)
-          # Can't use Base.create because the foreign key may be a protected attribute.
-          ensure_owner_is_persisted!
-          if attributes.is_a?(Array)
-            attributes.collect { |attr| create(attr) }
-          else
-            build_record(attributes, &block)
-          end
+        def select_value
+          super || reflection.klass.arel_table[Arel.star]
         end
 
-        def record_timestamp_columns(record)
-          if record.record_timestamps
-            record.send(:all_timestamp_attributes).map { |x| x.to_s }
-          else
-            []
-          end
+        def invertible_for?(record)
+          false
         end
     end
   end