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module ActiveRecord
class Relation
delegate :to_sql, :to => :relation
delegate :length, :collect, :find, :map, :each, :to => :to_a
attr_reader :relation, :klass
def initialize(klass, relation, readonly = false, preload = [], eager_load = [])
@klass, @relation = klass, relation
@readonly = readonly
@associations_to_preload = preload
@eager_load_associations = eager_load
@loaded = false
end
def preload(*associations)
create_new_relation(@relation, @readonly, @associations_to_preload + Array.wrap(associations))
end
def eager_load(*associations)
create_new_relation(@relation, @readonly, @associations_to_preload, @eager_load_associations + Array.wrap(associations))
end
def readonly
create_new_relation(@relation, true)
end
def select(selects)
create_new_relation(@relation.project(selects))
end
# TODO : This is temporary. We need .from in Arel.
attr_writer :from
def from(from)
relation = create_new_relation
relation.from = from
relation
end
def group(groups)
create_new_relation(@relation.group(groups))
end
def order(orders)
create_new_relation(@relation.order(orders))
end
def reverse_order
relation = create_new_relation
relation.instance_variable_set(:@orders, nil)
order_clause = @relation.send(:order_clauses).join(', ')
if order_clause.present?
relation.order(reverse_sql_order(order_clause))
else
relation.order("#{@klass.table_name}.#{@klass.primary_key} DESC")
end
end
def limit(limits)
create_new_relation(@relation.take(limits))
end
def offset(offsets)
create_new_relation(@relation.skip(offsets))
end
def on(join)
create_new_relation(@relation.on(join))
end
def joins(join, join_type = nil)
return self if join.blank?
join_relation = case join
when String
@relation.join(join)
when Hash, Array, Symbol
if @klass.send(:array_of_strings?, join)
@relation.join(join.join(' '))
else
@relation.join(@klass.send(:build_association_joins, join))
end
else
@relation.join(join, join_type)
end
create_new_relation(join_relation)
end
def where(*args)
return create_new_relation if args.blank?
if [String, Hash, Array].include?(args.first.class)
conditions = @klass.send(:merge_conditions, args.size > 1 ? Array.wrap(args) : args.first)
else
conditions = args.first
end
create_new_relation(@relation.where(conditions))
end
def respond_to?(method)
@relation.respond_to?(method) || Array.method_defined?(method) || super
end
def to_a
return @records if loaded?
@records = if @eager_load_associations.any?
catch :invalid_query do
return @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 => @from
},
ActiveRecord::Associations::ClassMethods::JoinDependency.new(@klass, @eager_load_associations, nil))
end
[]
else
@klass.find_by_sql(@relation.to_sql)
end
@associations_to_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 find(*ids, &block)
return to_a.find(&block) if block_given?
expects_array = ids.first.kind_of?(Array)
return ids.first if expects_array && ids.first.empty?
ids = ids.flatten.compact.uniq
case ids.size
when 0
raise RecordNotFound, "Couldn't find #{@klass.name} without an ID"
when 1
result = find_one(ids.first)
expects_array ? [ result ] : result
else
find_some(ids)
end
end
def exists?(id = nil)
relation = select("#{@klass.quoted_table_name}.#{@klass.primary_key}").limit(1)
relation = relation.where(@klass.primary_key => id) if id
relation.first ? true : false
end
def first
if loaded?
@records.first
else
@first ||= limit(1).to_a[0]
end
end
def last
if loaded?
@records.last
else
@last ||= reverse_order.limit(1).to_a[0]
end
end
def loaded?
@loaded
end
def reload
@loaded = false
@records = @first = @last = nil
self
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 find_by_attributes(match, attributes, *args)
conditions = attributes.inject({}) {|h, a| h[a] = args[attributes.index(a)]; h}
result = where(conditions).send(match.finder)
if match.bang? && result.blank?
raise RecordNotFound, "Couldn't find #{@klass.name} with #{conditions.to_a.collect {|p| p.join(' = ')}.join(', ')}"
else
result
end
end
def find_or_instantiator_by_attributes(match, attributes, *args)
guard_protected_attributes = false
if args[0].is_a?(Hash)
guard_protected_attributes = true
attributes_for_create = args[0].with_indifferent_access
conditions = attributes_for_create.slice(*attributes).symbolize_keys
else
attributes_for_create = conditions = attributes.inject({}) {|h, a| h[a] = args[attributes.index(a)]; h}
end
record = where(conditions).first
unless record
record = @klass.new { |r| r.send(:attributes=, attributes_for_create, guard_protected_attributes) }
yield(record) if block_given?
record.save if match.instantiator == :create
end
record
end
def find_one(id)
record = where(@klass.primary_key => id).first
unless record
conditions = where_clause(', ')
conditions = " [WHERE #{conditions}]" if conditions.present?
raise RecordNotFound, "Couldn't find #{@klass.name} with ID=#{id}#{conditions}"
end
record
end
def find_some(ids)
result = where(@klass.primary_key => ids).all
expected_size =
if @relation.taken && ids.size > @relation.taken
@relation.taken
else
ids.size
end
# 11 ids with limit 3, offset 9 should give 2 results.
if @relation.skipped && (ids.size - @relation.skipped < expected_size)
expected_size = ids.size - @relation.skipped
end
if result.size == expected_size
result
else
conditions = where_clause(', ')
conditions = " [WHERE #{conditions}]" if conditions.present?
error = "Couldn't find all #{@klass.name.pluralize} with IDs "
error << "(#{ids.join(", ")})#{conditions} (found #{result.size} results, but was looking for #{expected_size})"
raise RecordNotFound, error
end
end
def create_new_relation(relation = @relation, readonly = @readonly, preload = @associations_to_preload, eager_load = @eager_load_associations)
r = self.class.new(@klass, relation, readonly, preload, eager_load)
r.from = @from
r
end
def where_clause(join_string = "\n\tAND ")
@relation.send(:where_clauses).join(join_string)
end
def reverse_sql_order(order_query)
order_query.to_s.split(/,/).each { |s|
if s.match(/\s(asc|ASC)$/)
s.gsub!(/\s(asc|ASC)$/, ' DESC')
elsif s.match(/\s(desc|DESC)$/)
s.gsub!(/\s(desc|DESC)$/, ' ASC')
else
s.concat(' DESC')
end
}.join(',')
end
end
end
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