require 'set' module ActiveRecord module Associations # AssociationCollection is an abstract class that provides common stuff to # ease the implementation of association proxies that represent # collections. See the class hierarchy in AssociationProxy. # # You need to be careful with assumptions regarding the target: The proxy # does not fetch records from the database until it needs them, but new # ones created with +build+ are added to the target. So, the target may be # non-empty and still lack children waiting to be read from the database. # If you look directly to the database you cannot assume that's the entire # collection because new records may have been added to the target, etc. # # If you need to work on all current children, new and existing records, # +load_target+ and the +loaded+ flag are your friends. class AssociationCollection < AssociationProxy #:nodoc: def initialize(owner, reflection) super construct_sql end delegate :group, :order, :limit, :joins, :where, :preload, :eager_load, :includes, :from, :lock, :readonly, :having, :to => :scoped def select(select = nil, &block) if block_given? load_target @target.select(&block) else scoped.select(select) end end def scoped with_scope(construct_scope) { @reflection.klass.scoped } end def find(*args) options = args.extract_options! # If using a custom finder_sql, scan the entire collection. if @reflection.options[:finder_sql] expects_array = args.first.kind_of?(Array) ids = args.flatten.compact.uniq.map { |arg| arg.to_i } if ids.size == 1 id = ids.first record = load_target.detect { |r| id == r.id } expects_array ? [ record ] : record else load_target.select { |r| ids.include?(r.id) } end else merge_options_from_reflection!(options) construct_find_options!(options) find_scope = construct_scope[:find].slice(:conditions, :order) with_scope(:find => find_scope) do relation = @reflection.klass.send(:construct_finder_arel, options, @reflection.klass.send(:current_scoped_methods)) case args.first when :first, :last relation.send(args.first) when :all records = relation.all @reflection.options[:uniq] ? uniq(records) : records else relation.find(*args) end end end end # Fetches the first one 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 # Fetches the last one 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 if @target.is_a?(Array) @target.to_ary else Array(@target) end end alias_method :to_a, :to_ary def reset reset_target! @loaded = false end def build(attributes = {}, &block) if attributes.is_a?(Array) attributes.collect { |attr| build(attr, &block) } else build_record(attributes) do |record| block.call(record) if block_given? set_belongs_to_association_for(record) end end end # Add +records+ to this association. Returns +self+ so method calls may be chained. # Since << flattens its argument list and inserts each record, +push+ and +concat+ behave identically. def <<(*records) result = true load_target if @owner.new_record? transaction do flatten_deeper(records).each do |record| raise_on_type_mismatch(record) add_record_to_target_with_callbacks(record) do |r| result &&= insert_record(record) unless @owner.new_record? end end end result && self end alias_method :push, :<< alias_method :concat, :<< # Starts a transaction in the association class's database connection. # # class Author < ActiveRecord::Base # has_many :books # end # # Author.find(:first).books.transaction do # # same effect as calling Book.transaction # end def transaction(*args) @reflection.klass.transaction(*args) do yield end end # Remove all records from this association # # See delete for more info. def delete_all load_target delete(@target) reset_target! end # Calculate sum using SQL, not Enumerable def sum(*args) if block_given? calculate(:sum, *args) { |*block_args| yield(*block_args) } else calculate(:sum, *args) end end # Count all records using SQL. If the +:counter_sql+ option is set for the association, it will # be used for the query. If no +:counter_sql+ was supplied, but +:finder_sql+ was set, the # descendant's +construct_sql+ method will have set :counter_sql automatically. # Otherwise, construct options and pass them with scope to the target class's +count+. def count(column_name = nil, options = {}) if @reflection.options[:counter_sql] @reflection.klass.count_by_sql(@counter_sql) else column_name, options = nil, column_name if column_name.is_a?(Hash) if @reflection.options[:uniq] # This is needed because 'SELECT count(DISTINCT *)..' is not valid SQL. column_name = "#{@reflection.quoted_table_name}.#{@reflection.klass.primary_key}" unless column_name options.merge!(:distinct => true) end value = @reflection.klass.send(:with_scope, construct_scope) { @reflection.klass.count(column_name, options) } limit = @reflection.options[:limit] offset = @reflection.options[:offset] if limit || offset [ [value - offset.to_i, 0].max, limit.to_i ].min else value end end end # Removes +records+ from this association calling +before_remove+ and # +after_remove+ callbacks. # # This method is abstract in the sense that +delete_records+ has to be # provided by descendants. Note this method does not imply the records # are actually removed from the database, that depends precisely on # +delete_records+. They are in any case removed from the collection. def delete(*records) remove_records(records) do |records, old_records| delete_records(old_records) if old_records.any? records.each { |record| @target.delete(record) } end end # Destroy +records+ and remove them from this association calling # +before_remove+ and +after_remove+ callbacks. # # Note that this method will _always_ remove records from the database # ignoring the +:dependent+ option. def destroy(*records) records = find(records) if records.any? {|record| record.kind_of?(Fixnum) || record.kind_of?(String)} remove_records(records) do |records, old_records| old_records.each { |record| record.destroy } end load_target end # Removes all records from this association. Returns +self+ so method calls may be chained. def clear return self if length.zero? # forces load_target if it hasn't happened already if @reflection.options[:dependent] && @reflection.options[:dependent] == :destroy destroy_all else delete_all end self end # Destroy all the records from this association. # # See destroy for more info. def destroy_all load_target destroy(@target) reset_target! end def create(attrs = {}) if attrs.is_a?(Array) attrs.collect { |attr| create(attr) } else create_record(attrs) do |record| yield(record) if block_given? record.save end end end def create!(attrs = {}) create_record(attrs) do |record| yield(record) if block_given? record.save! end end # Returns the size of the collection by executing a SELECT COUNT(*) # query if the collection hasn't been loaded, and calling # collection.size if it has. # # If the collection has been already loaded +size+ and +length+ are # equivalent. If not and you are going to need the records anyway # +length+ will take one less query. Otherwise +size+ is more efficient. # # This method is abstract in the sense that it relies on # +count_records+, which is a method descendants have to provide. def size if @owner.new_record? || (loaded? && !@reflection.options[:uniq]) @target.size elsif !loaded? && @reflection.options[:group] load_target.size elsif !loaded? && !@reflection.options[:uniq] && @target.is_a?(Array) unsaved_records = @target.select { |r| r.new_record? } unsaved_records.size + count_records else count_records end end # Returns the size of the collection calling +size+ on the target. # # If the collection has been already loaded +length+ and +size+ are # equivalent. If not and you are going to need the records anyway this # method will take one less query. Otherwise +size+ is more efficient. def length load_target.size end # Equivalent to collection.size.zero?. If the collection has # not been already loaded and you are going to fetch the records anyway # it is better to check collection.length.zero?. def empty? size.zero? end def any? if block_given? method_missing(:any?) { |*block_args| yield(*block_args) } else !empty? end end # Returns true if the collection has more than 1 record. Equivalent to collection.size > 1. def many? if block_given? method_missing(:many?) { |*block_args| yield(*block_args) } else size > 1 end end def uniq(collection = self) seen = Set.new collection.inject([]) do |kept, record| unless seen.include?(record.id) kept << record seen << record.id end kept end end # Replace this collection with +other_array+ # This will perform a diff and delete/add only records that have changed. def replace(other_array) other_array.each { |val| raise_on_type_mismatch(val) } load_target other = other_array.size < 100 ? other_array : other_array.to_set current = @target.size < 100 ? @target : @target.to_set transaction do delete(@target.select { |v| !other.include?(v) }) concat(other_array.select { |v| !current.include?(v) }) end end def include?(record) return false unless record.is_a?(@reflection.klass) load_target if @reflection.options[:finder_sql] && !loaded? return @target.include?(record) if loaded? exists?(record) end def proxy_respond_to?(method, include_private = false) super || @reflection.klass.respond_to?(method, include_private) end protected def construct_find_options!(options) end def construct_counter_sql if @reflection.options[:counter_sql] @counter_sql = interpolate_sql(@reflection.options[:counter_sql]) elsif @reflection.options[:finder_sql] # replace the SELECT clause with COUNT(*), preserving any hints within /* ... */ @reflection.options[:counter_sql] = @reflection.options[:finder_sql].sub(/SELECT\b(\/\*.*?\*\/ )?(.*)\bFROM\b/im) { "SELECT #{$1}COUNT(*) FROM" } @counter_sql = interpolate_sql(@reflection.options[:counter_sql]) else @counter_sql = @finder_sql end end def load_target if !@owner.new_record? || foreign_key_present begin if !loaded? if @target.is_a?(Array) && @target.any? @target = find_target + @target.find_all {|t| t.new_record? } else @target = find_target end end rescue ActiveRecord::RecordNotFound reset end end loaded if target target end def method_missing(method, *args) if @target.respond_to?(method) || (!@reflection.klass.respond_to?(method) && Class.respond_to?(method)) if block_given? super { |*block_args| yield(*block_args) } else super end else with_scope(construct_scope) do if block_given? @reflection.klass.send(method, *args) { |*block_args| yield(*block_args) } else @reflection.klass.send(method, *args) end end end end # overloaded in derived Association classes to provide useful scoping depending on association type. def construct_scope {} end def reset_target! @target = Array.new end def find_target records = if @reflection.options[:finder_sql] @reflection.klass.find_by_sql(@finder_sql) else find(:all) end records = @reflection.options[:uniq] ? uniq(records) : records records.each do |record| set_inverse_instance(record, @owner) end records end private def create_record(attrs) attrs.update(@reflection.options[:conditions]) if @reflection.options[:conditions].is_a?(Hash) ensure_owner_is_not_new record = @reflection.klass.send(:with_scope, :create => construct_scope[:create]) do @reflection.build_association(attrs) end if block_given? add_record_to_target_with_callbacks(record) { |*block_args| yield(*block_args) } else add_record_to_target_with_callbacks(record) end end def build_record(attrs) attrs.update(@reflection.options[:conditions]) if @reflection.options[:conditions].is_a?(Hash) record = @reflection.build_association(attrs) if block_given? add_record_to_target_with_callbacks(record) { |*block_args| yield(*block_args) } else add_record_to_target_with_callbacks(record) end end def add_record_to_target_with_callbacks(record) callback(:before_add, record) yield(record) if block_given? @target ||= [] unless loaded? @target << record unless @reflection.options[:uniq] && @target.include?(record) callback(:after_add, record) set_inverse_instance(record, @owner) record end def remove_records(*records) records = flatten_deeper(records) records.each { |record| raise_on_type_mismatch(record) } transaction do records.each { |record| callback(:before_remove, record) } old_records = records.reject { |r| r.new_record? } yield(records, old_records) records.each { |record| callback(:after_remove, record) } end end def callback(method, record) callbacks_for(method).each do |callback| case callback when Symbol @owner.send(callback, record) when Proc callback.call(@owner, record) else callback.send(method, @owner, record) end end end def callbacks_for(callback_name) full_callback_name = "#{callback_name}_for_#{@reflection.name}" @owner.class.read_inheritable_attribute(full_callback_name.to_sym) || [] end def ensure_owner_is_not_new if @owner.new_record? 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.any? { |record| record.new_record? } || args.first.kind_of?(Integer)) end end end end