module ActiveRecord
class Relation
include QueryMethods, FinderMethods, CalculationMethods
delegate :length, :collect, :map, :each, :all?, :to => :to_a
attr_reader :relation, :klass
attr_writer :readonly, :table
attr_accessor :preload_associations, :eager_load_associations, :include_associations
def initialize(klass, relation)
@klass, @relation = klass, relation
@preload_associations = []
@eager_load_associations = []
@include_associations = []
@loaded, @readonly = false
end
def new(*args, &block)
with_create_scope { @klass.new(*args, &block) }
end
def create(*args, &block)
with_create_scope { @klass.create(*args, &block) }
end
def create!(*args, &block)
with_create_scope { @klass.create!(*args, &block) }
end
def merge(r)
raise ArgumentError, "Cannot merge a #{r.klass.name} relation with #{@klass.name} relation" if r.klass != @klass
merged_relation = spawn(table).eager_load(r.eager_load_associations).preload(r.preload_associations).includes(r.include_associations)
merged_relation.readonly = r.readonly
[self.relation, r.relation].each do |arel|
merged_relation = merged_relation.
joins(arel.joins(arel)).
group(arel.groupings).
order(arel.send(:order_clauses).join(', ')).
limit(arel.taken).
offset(arel.skipped).
select(arel.send(:select_clauses)).
from(arel.sources)
end
merged_wheres = @relation.wheres
r.wheres.each do |w|
if w.is_a?(Arel::Predicates::Equality)
merged_wheres = merged_wheres.reject {|p| p.is_a?(Arel::Predicates::Equality) && p.operand1.name == w.operand1.name }
end
merged_wheres << w
end
merged_relation.where(*merged_wheres)
end
alias :& :merge
def respond_to?(method, include_private = false)
return true if @relation.respond_to?(method, include_private) || Array.method_defined?(method)
if match = DynamicFinderMatch.match(method)
return true if @klass.send(:all_attributes_exists?, match.attribute_names)
elsif match = DynamicScopeMatch.match(method)
return true if @klass.send(:all_attributes_exists?, match.attribute_names)
else
super
end
end
def to_a
return @records if loaded?
find_with_associations = @eager_load_associations.any? || references_eager_loaded_tables?
@records = if find_with_associations
begin
@klass.send(:find_with_associations, {
:select => @relation.send(:select_clauses).join(', '),
:joins => @relation.joins(relation),
:group => @relation.send(:group_clauses).join(', '),
:order => @relation.send(:order_clauses).join(', '),
:conditions => where_clause,
:limit => @relation.taken,
:offset => @relation.skipped,
:from => (@relation.send(:from_clauses) if @relation.send(:sources).present?)
},
ActiveRecord::Associations::ClassMethods::JoinDependency.new(@klass, @eager_load_associations + @include_associations, nil))
rescue ThrowResult
[]
end
else
@klass.find_by_sql(@relation.to_sql)
end
preload = @preload_associations
preload += @include_associations unless find_with_associations
preload.each {|associations| @klass.send(:preload_associations, @records, associations) }
@records.each { |record| record.readonly! } if @readonly
@loaded = true
@records
end
alias all to_a
def size
loaded? ? @records.length : count
end
def empty?
loaded? ? @records.empty? : count.zero?
end
def any?
if block_given?
to_a.any? { |*block_args| yield(*block_args) }
else
!empty?
end
end
def many?
if block_given?
to_a.many? { |*block_args| yield(*block_args) }
else
@relation.send(:taken).present? ? to_a.many? : size > 1
end
end
def destroy_all
to_a.each {|object| object.destroy}
reset
end
def delete_all
@relation.delete.tap { reset }
end
def delete(id_or_array)
where(@klass.primary_key => id_or_array).delete_all
end
def loaded?
@loaded
end
def reload
@loaded = false
reset
end
def reset
@first = @last = @create_scope = @to_sql = nil
@records = []
self
end
def spawn(relation = @relation)
relation = Relation.new(@klass, relation)
relation.readonly = @readonly
relation.preload_associations = @preload_associations
relation.eager_load_associations = @eager_load_associations
relation.include_associations = @include_associations
relation.table = table
relation
end
def table
@table ||= Arel::Table.new(@klass.table_name, Arel::Sql::Engine.new(@klass))
end
def primary_key
@primary_key ||= table[@klass.primary_key]
end
def to_sql
@to_sql ||= @relation.to_sql
end
protected
def method_missing(method, *args, &block)
if @relation.respond_to?(method)
@relation.send(method, *args, &block)
elsif Array.method_defined?(method)
to_a.send(method, *args, &block)
elsif match = DynamicFinderMatch.match(method)
attributes = match.attribute_names
super unless @klass.send(:all_attributes_exists?, attributes)
if match.finder?
find_by_attributes(match, attributes, *args)
elsif match.instantiator?
find_or_instantiator_by_attributes(match, attributes, *args, &block)
end
else
super
end
end
def with_create_scope
@klass.send(:with_scope, :create => create_scope) { yield }
end
def create_scope
@create_scope ||= wheres.inject({}) do |hash, where|
hash[where.operand1.name] = where.operand2.value if where.is_a?(Arel::Predicates::Equality)
hash
end
end
def where_clause(join_string = " AND ")
@relation.send(:where_clauses).join(join_string)
end
def references_eager_loaded_tables?
joined_tables = (tables_in_string(@relation.joins(relation)) + [table.name, table.table_alias]).compact.uniq
(tables_in_string(to_sql) - joined_tables).any?
end
def tables_in_string(string)
return [] if string.blank?
string.scan(/([a-zA-Z_][\.\w]+).?\./).flatten.uniq
end
end
end