breaking classes up in to respective files

1 files changed, 278 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/associations/class_methods/join_dependency/join_association.rb b/activerecord/lib/active_record/associations/class_methods/join_dependency/join_association.rb
new file mode 100644
index 0000000000..5e5c01c77a
--- /dev/null
+++ b/activerecord/lib/active_record/associations/class_methods/join_dependency/join_association.rb
@@ -0,0 +1,278 @@
+module ActiveRecord
+  module Associations
+    module ClassMethods
+      class JoinDependency # :nodoc:
+        class JoinAssociation < JoinPart # :nodoc:
+          # The reflection of the association represented
+          attr_reader :reflection
+
+          # The JoinDependency object which this JoinAssociation exists within. This is mainly
+          # relevant for generating aliases which do not conflict with other joins which are
+          # part of the query.
+          attr_reader :join_dependency
+
+          # A JoinBase instance representing the active record we are joining onto.
+          # (So in Author.has_many :posts, the Author would be that base record.)
+          attr_reader :parent
+
+          # What type of join will be generated, either Arel::InnerJoin (default) or Arel::OuterJoin
+          attr_accessor :join_type
+
+          # These implement abstract methods from the superclass
+          attr_reader :aliased_prefix, :aliased_table_name
+
+          delegate :options, :through_reflection, :source_reflection, :to => :reflection
+          delegate :table, :table_name, :to => :parent, :prefix => true
+
+          def initialize(reflection, join_dependency, parent = nil)
+            reflection.check_validity!
+
+            if reflection.options[:polymorphic]
+              raise EagerLoadPolymorphicError.new(reflection)
+            end
+
+            super(reflection.klass)
+
+            @reflection      = reflection
+            @join_dependency = join_dependency
+            @parent          = parent
+            @join_type       = Arel::InnerJoin
+
+            # This must be done eagerly upon initialisation because the alias which is produced
+            # depends on the state of the join dependency, but we want it to work the same way
+            # every time.
+            allocate_aliases
+          end
+
+          def ==(other)
+            other.class == self.class &&
+              other.reflection == reflection &&
+              other.parent == parent
+          end
+
+          def find_parent_in(other_join_dependency)
+            other_join_dependency.join_parts.detect do |join_part|
+              self.parent == join_part
+            end
+          end
+
+          def join_to(relation)
+            send("join_#{reflection.macro}_to", relation)
+          end
+
+          def join_relation(joining_relation)
+            self.join_type = Arel::OuterJoin
+            joining_relation.joins(self)
+          end
+
+          def table
+            @table ||= Arel::Table.new(
+              table_name, :as => aliased_table_name,
+              :engine => arel_engine, :columns => active_record.columns
+            )
+          end
+
+          # More semantic name given we are talking about associations
+          alias_method :target_table, :table
+
+          protected
+
+          def aliased_table_name_for(name, suffix = nil)
+            if @join_dependency.table_aliases[name].zero?
+              @join_dependency.table_aliases[name] = @join_dependency.count_aliases_from_table_joins(name)
+            end
+
+            if !@join_dependency.table_aliases[name].zero? # We need an alias
+              name = active_record.connection.table_alias_for "#{pluralize(reflection.name)}_#{parent_table_name}#{suffix}"
+              @join_dependency.table_aliases[name] += 1
+              if @join_dependency.table_aliases[name] == 1 # First time we've seen this name
+                # Also need to count the aliases from the table_aliases to avoid incorrect count
+                @join_dependency.table_aliases[name] += @join_dependency.count_aliases_from_table_joins(name)
+              end
+              table_index = @join_dependency.table_aliases[name]
+              name = name[0..active_record.connection.table_alias_length-3] + "_#{table_index}" if table_index > 1
+            else
+              @join_dependency.table_aliases[name] += 1
+            end
+
+            name
+          end
+
+          def pluralize(table_name)
+            ActiveRecord::Base.pluralize_table_names ? table_name.to_s.pluralize : table_name
+          end
+
+          def interpolate_sql(sql)
+            instance_eval("%@#{sql.gsub('@', '\@')}@", __FILE__, __LINE__)
+          end
+
+          private
+
+          def allocate_aliases
+            @aliased_prefix     = "t#{ join_dependency.join_parts.size }"
+            @aliased_table_name = aliased_table_name_for(table_name)
+
+            if reflection.macro == :has_and_belongs_to_many
+              @aliased_join_table_name = aliased_table_name_for(reflection.options[:join_table], "_join")
+            elsif [:has_many, :has_one].include?(reflection.macro) && reflection.options[:through]
+              @aliased_join_table_name = aliased_table_name_for(reflection.through_reflection.klass.table_name, "_join")
+            end
+          end
+
+          def process_conditions(conditions, table_name)
+            Arel.sql(interpolate_sql(sanitize_sql(conditions, table_name)))
+          end
+
+          def join_target_table(relation, *conditions)
+            relation = relation.join(target_table, join_type)
+
+            # If the target table is an STI model then we must be sure to only include records of
+            # its type and its sub-types.
+            unless active_record.descends_from_active_record?
+              sti_column = target_table[active_record.inheritance_column]
+
+              sti_condition = sti_column.eq(active_record.sti_name)
+              active_record.descendants.each do |subclass|
+                sti_condition = sti_condition.or(sti_column.eq(subclass.sti_name))
+              end
+
+              conditions << sti_condition
+            end
+
+            # If the reflection has conditions, add them
+            if options[:conditions]
+              conditions << process_conditions(options[:conditions], aliased_table_name)
+            end
+
+            relation = relation.on(*conditions)
+          end
+
+          def join_has_and_belongs_to_many_to(relation)
+            join_table = Arel::Table.new(
+              options[:join_table], :engine => arel_engine,
+              :as => @aliased_join_table_name
+            )
+
+            fk       = options[:foreign_key]             || reflection.active_record.to_s.foreign_key
+            klass_fk = options[:association_foreign_key] || reflection.klass.to_s.foreign_key
+
+            relation = relation.join(join_table, join_type)
+            relation = relation.on(
+              join_table[fk].
+              eq(parent_table[reflection.active_record.primary_key])
+            )
+
+            join_target_table(
+              relation,
+              target_table[reflection.klass.primary_key].
+              eq(join_table[klass_fk])
+            )
+          end
+
+          def join_has_many_to(relation)
+            if reflection.options[:through]
+              join_has_many_through_to(relation)
+            elsif reflection.options[:as]
+              join_has_many_polymorphic_to(relation)
+            else
+              foreign_key = options[:foreign_key] || reflection.active_record.name.foreign_key
+              primary_key = options[:primary_key] || parent.primary_key
+
+              join_target_table(
+                relation,
+                target_table[foreign_key].
+                eq(parent_table[primary_key])
+              )
+            end
+          end
+          alias :join_has_one_to :join_has_many_to
+
+          def join_has_many_through_to(relation)
+            join_table = Arel::Table.new(
+              through_reflection.klass.table_name, :engine => arel_engine,
+              :as => @aliased_join_table_name
+            )
+
+            jt_conditions = []
+            jt_foreign_key = first_key = second_key = nil
+
+            if through_reflection.options[:as] # has_many :through against a polymorphic join
+              as_key         = through_reflection.options[:as].to_s
+              jt_foreign_key = as_key + '_id'
+
+              jt_conditions <<
+              join_table[as_key + '_type'].
+                eq(parent.active_record.base_class.name)
+            else
+              jt_foreign_key = through_reflection.primary_key_name
+            end
+
+            case source_reflection.macro
+            when :has_many
+              second_key = options[:foreign_key] || primary_key
+
+              if source_reflection.options[:as]
+                first_key = "#{source_reflection.options[:as]}_id"
+              else
+                first_key = through_reflection.klass.base_class.to_s.foreign_key
+              end
+
+              unless through_reflection.klass.descends_from_active_record?
+                jt_conditions <<
+                join_table[through_reflection.active_record.inheritance_column].
+                  eq(through_reflection.klass.sti_name)
+              end
+            when :belongs_to
+              first_key = primary_key
+
+              if reflection.options[:source_type]
+                second_key = source_reflection.association_foreign_key
+
+                jt_conditions <<
+                join_table[reflection.source_reflection.options[:foreign_type]].
+                  eq(reflection.options[:source_type])
+              else
+                second_key = source_reflection.primary_key_name
+              end
+            end
+
+            jt_conditions <<
+            parent_table[parent.primary_key].
+              eq(join_table[jt_foreign_key])
+
+            if through_reflection.options[:conditions]
+              jt_conditions << process_conditions(through_reflection.options[:conditions], aliased_table_name)
+            end
+
+            relation = relation.join(join_table, join_type).on(*jt_conditions)
+
+            join_target_table(
+              relation,
+              target_table[first_key].eq(join_table[second_key])
+            )
+          end
+
+          def join_has_many_polymorphic_to(relation)
+            join_target_table(
+              relation,
+              target_table["#{reflection.options[:as]}_id"].
+              eq(parent_table[parent.primary_key]),
+              target_table["#{reflection.options[:as]}_type"].
+              eq(parent.active_record.base_class.name)
+            )
+          end
+
+          def join_belongs_to_to(relation)
+            foreign_key = options[:foreign_key] || reflection.primary_key_name
+            primary_key = options[:primary_key] || reflection.klass.primary_key
+
+            join_target_table(
+              relation,
+              target_table[primary_key].eq(parent_table[foreign_key])
+            )
+          end
+        end
+      end
+    end
+  end
+end