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require 'set'
require 'active_support/core_ext/array/wrap'
module ActiveRecord
module Associations
# = Active Record Association Collection
#
# 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.wrap(@target)
end
end
alias_method :to_a, :to_ary
def reset
reset_target!
reset_named_scopes_cache!
@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.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!
reset_named_scopes_cache!
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!
reset_named_scopes_cache!
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
# <tt>collection.size</tt> 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 <tt>collection.size.zero?</tt>. If the collection has
# not been already loaded and you are going to fetch the records anyway
# it is better to check <tt>collection.length.zero?</tt>.
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
elsif @reflection.klass.scopes[method]
@_named_scopes_cache ||= {}
@_named_scopes_cache[method] ||= {}
@_named_scopes_cache[method][args] ||= with_scope(construct_scope) { @reflection.klass.send(method, *args) }
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 reset_named_scopes_cache!
@_named_scopes_cache = {}
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
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
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 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
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