Permalink
Browse files

Use explicit delegations

This makes it easier to see what the documentation refers to.

It also means that we are not doing unnecessary work for delegations
that have no args / splats / block / etc.
  • Loading branch information...
1 parent 66aaca4 commit 26d3e325cb85884504564b8af07dd083fc47d2a8 @jonleighton jonleighton committed Aug 1, 2012
Showing with 79 additions and 119 deletions.
  1. +79 −119 activerecord/lib/active_record/associations/collection_proxy.rb
@@ -34,15 +34,25 @@ module Associations
# is computed directly through SQL and does not trigger by itself the
# instantiation of the actual post records.
class CollectionProxy < Relation
- delegate :target, :load_target, :loaded?, :to => :@association
+ def initialize(association) #:nodoc:
+ @association = association
+ super association.klass, association.klass.arel_table
+ merge! association.scoped
+ end
+
+ def target
+ @association.target
+ end
+
+ def load_target
+ @association.load_target
+ end
+
+ def loaded?
@stanio

stanio Oct 31, 2016

This appears to conflict with e1df4b9 (20 Jul 2010):

--- a/activerecord/lib/active_record/relation.rb
+++ b/activerecord/lib/active_record/relation.rb
@@ -13,14 +13,15 @@ class Relation
     delegate :to_xml, :to_yaml, :length, :collect, :map, :each, :all?, :include?, :to => :to_a
     delegate :insert, :to => :arel

-    attr_reader :table, :klass
+    attr_reader :table, :klass, :loaded
     attr_accessor :extensions
+    alias :loaded? :loaded

     def initialize(klass, table)
       @klass, @table = klass, table

The following gives unexpected results:

class MyRecord < ActiveRecord::Base
  has_many :my_items
end

class MyItem < ActiveRecord::Base
  belongs_to :my_record
end
rec = MyRecord.find(123) # MyRecord Load
rec.my_items.load    # MyItem Load
rec.my_items.loaded? # => false
rec.my_items.loaded  # => true
rec.my_items.to_a    # MyItem Load again
rec.my_items.loaded? # => true
rec.my_items.loaded  # => true
rec.my_items.to_a    # No database loading

The following behaves as expected regarding database loading, but still shows inconsistent loaded? vs. loaded:

rec = MyRecord.find(123) # MyRecord Load
rec.my_items.to_a    # MyItem Load
rec.my_items.loaded? # => true
rec.my_items.loaded  # => false
rec.my_items.to_a    # No database loading

or:

rec = MyRecord.find(123) # MyRecord Load
rec.my_items.reload  # MyItem Load
rec.my_items.loaded? # => true
rec.my_items.loaded  # => false
rec.my_items.to_a    # No database loading
@stanio

stanio Oct 31, 2016 edited

The more complex example I was after while I've encountered this is like:

class MyRecord < ActiveRecord::Base
  has_many :my_items
end

class MyItem < ActiveRecord::Base
  belongs_to :my_record
  belongs_to :my_type_info
end

class MyTypeInfo < ActiveRecord::Base; end
rec = MyRecord.find(123) # MyRecord Load
rec.my_items.eager_load!(:my_type_info)
rec.my_items.to_a # MyItem Load (no my_type_info loaded)

Then I've tried:

rec = MyRecord.find(123) # MyRecord Load
rec.my_items.eager_load!(:my_type_info)
rec.my_items.load    # MyItem Load with my_type_info
rec.my_items.loaded? # => false
rec.my_items.loaded  # => true
rec.my_items.to_a    # MyItem Load (no my_type_info loaded)
rec.my_items.loaded? # => true
rec.my_items.loaded  # => true
@stanio

stanio Oct 31, 2016

So this change may not be the root cause of my problem. I've found the following generally achieves the desired effect:

rec = MyRecord.find(123) # MyRecord Load
rec.my_items.proxy_association.association_scope.eager_load!(:my_type_info)
rec.my_items.each { }    # MyItem Load with my_type_info
rec.my_items.to_a        # No database loading
+ @association.loaded?
+ end
##
- # :method: select
- #
- # :call-seq:
- # select(select = nil)
- # select(&block)
- #
# Works in two ways.
#
# *First:* Specify a subset of fields to be selected from the result set.
@@ -96,13 +106,11 @@ class CollectionProxy < Relation
# # #<Pet id: 2, name: "Spook">,
# # #<Pet id: 3, name: "Choo-Choo">
# # ]
+ def select(select = nil, &block)
+ @association.select(select, &block)
+ end
##
- # :method: find
- #
- # :call-seq:
- # find(*args, &block)
- #
# Finds an object in the collection responding to the +id+. Uses the same
# rules as +ActiveRecord::Base.find+. Returns +ActiveRecord::RecordNotFound++
# error if the object can not be found.
@@ -129,13 +137,11 @@ class CollectionProxy < Relation
# # #<Pet id: 2, name: "Spook", person_id: 1>,
# # #<Pet id: 3, name: "Choo-Choo", person_id: 1>
# # ]
+ def find(*args, &block)
+ @association.find(*args, &block)
+ end
##
- # :method: first
- #
- # :call-seq:
- # first(limit = nil)
- #
# Returns the first record, or the first +n+ records, from the collection.
# If the collection is empty, the first form returns +nil+, and the second
# form returns an empty array.
@@ -162,13 +168,11 @@ class CollectionProxy < Relation
# another_person_without.pets # => []
# another_person_without.pets.first # => nil
# another_person_without.pets.first(3) # => []
+ def first(*args)
+ @association.first(*args)
+ end
##
- # :method: last
- #
- # :call-seq:
- # last(limit = nil)
- #
# Returns the last record, or the last +n+ records, from the collection.
# If the collection is empty, the first form returns +nil+, and the second
# form returns an empty array.
@@ -195,13 +199,11 @@ class CollectionProxy < Relation
# another_person_without.pets # => []
# another_person_without.pets.last # => nil
# another_person_without.pets.last(3) # => []
+ def last(*args)
+ @association.last(*args)
+ end
##
- # :method: build
- #
- # :call-seq:
- # build(attributes = {}, options = {}, &block)
- #
# Returns a new object of the collection type that has been instantiated
# with +attributes+ and linked to this object, but have not yet been saved.
# You can pass an array of attributes hashes, this will return an array
@@ -226,13 +228,11 @@ class CollectionProxy < Relation
#
# person.pets.size # => 5 # size of the collection
# person.pets.count # => 0 # count from database
+ def build(attributes = {}, options = {}, &block)
+ @association.build(attributes, options, &block)
+ end
##
- # :method: create
- #
- # :call-seq:
- # create(attributes = {}, options = {}, &block)
- #
# Returns a new object of the collection type that has been instantiated with
# attributes, linked to this object and that has already been saved (if it
# passes the validations).
@@ -259,13 +259,11 @@ class CollectionProxy < Relation
# # #<Pet id: 2, name: "Spook", person_id: 1>,
# # #<Pet id: 3, name: "Choo-Choo", person_id: 1>
# # ]
+ def create(attributes = {}, options = {}, &block)
+ @association.create(attributes, options, &block)
+ end
##
- # :method: create!
- #
- # :call-seq:
- # create!(attributes = {}, options = {}, &block)
- #
# Like +create+, except that if the record is invalid, raises an exception.
#
# class Person
@@ -279,13 +277,11 @@ class CollectionProxy < Relation
#
# person.pets.create!(name: nil)
# # => ActiveRecord::RecordInvalid: Validation failed: Name can't be blank
+ def create!(attributes = {}, options = {}, &block)
+ @association.create!(attributes, options, &block)
+ end
##
- # :method: concat
- #
- # :call-seq:
- # concat(*records)
- #
# Add one or more records to the collection by setting their foreign keys
# to the association's primary key. Since << flattens its argument list and
# inserts each record, +push+ and +concat+ behave identically. Returns +self+
@@ -310,13 +306,11 @@ class CollectionProxy < Relation
#
# person.pets.concat([Pet.new(name: 'Brain'), Pet.new(name: 'Benny')])
# person.pets.size # => 5
+ def concat(*records)
+ @association.concat(*records)
+ end
##
- # :method: replace
- #
- # :call-seq:
- # replace(other_array)
- #
# Replace this collection with +other_array+. This will perform a diff
# and delete/add only records that have changed.
#
@@ -339,13 +333,11 @@ class CollectionProxy < Relation
#
# person.pets.replace(["doo", "ggie", "gaga"])
# # => ActiveRecord::AssociationTypeMismatch: Pet expected, got String
+ def replace(other_array)
+ @association.replace(other_array)
+ end
##
- # :method: delete_all
- #
- # :call-seq:
- # delete_all()
- #
# Deletes all the records from the collection. For +has_many+ associations,
# the deletion is done according to the strategy specified by the <tt>:dependent</tt>
# option. Returns an array with the deleted records.
@@ -434,13 +426,11 @@ class CollectionProxy < Relation
#
# Pet.find(1, 2, 3)
# # => ActiveRecord::RecordNotFound
+ def delete_all
+ @association.delete_all
+ end
##
- # :method: destroy_all
- #
- # :call-seq:
- # destroy_all()
- #
# Deletes the records of the collection directly from the database.
# This will _always_ remove the records ignoring the +:dependent+
# option.
@@ -463,15 +453,11 @@ class CollectionProxy < Relation
# person.pets # => []
#
# Pet.find(1) # => Couldn't find Pet with id=1
+ def destroy_all
+ @association.destroy_all
+ end
##
- # :method: delete
- #
- # :call-seq:
- # delete(*records)
- # delete(*fixnum_ids)
- # delete(*string_ids)
- #
# Deletes the +records+ supplied and removes them from the collection. For
# +has_many+ associations, the deletion is done according to the strategy
# specified by the <tt>:dependent</tt> option. Returns an array with the
@@ -586,13 +572,11 @@ class CollectionProxy < Relation
# # #<Pet id: 2, name: "Spook", person_id: 1>,
# # #<Pet id: 3, name: "Choo-Choo", person_id: 1>
# # ]
+ def delete(*records)
+ @association.delete(*records)
+ end
##
- # :method: destroy
- #
- # :call-seq:
- # destroy(*records)
- #
# Destroys the +records+ supplied and removes them from the collection.
# This method will _always_ remove record from the database ignoring
# the +:dependent+ option. Returns an array with the removed records.
@@ -661,13 +645,11 @@ class CollectionProxy < Relation
# person.pets # => []
#
# Pet.find(4, 5, 6) # => ActiveRecord::RecordNotFound: Couldn't find all Pets with IDs (4, 5, 6)
+ def destroy(*records)
+ @association.destroy(*records)
+ end
##
- # :method: uniq
- #
- # :call-seq:
- # uniq()
- #
# Specifies whether the records should be unique or not.
#
# class Person < ActiveRecord::Base
@@ -682,13 +664,11 @@ class CollectionProxy < Relation
#
# person.pets.select(:name).uniq
# # => [#<Pet name: "Fancy-Fancy">]
+ def uniq
+ @association.uniq
+ end
##
- # :method: count
- #
- # :call-seq:
- # count()
- #
# Count all records using SQL.
#
# class Person < ActiveRecord::Base
@@ -702,13 +682,11 @@ class CollectionProxy < Relation
# # #<Pet id: 2, name: "Spook", person_id: 1>,
# # #<Pet id: 3, name: "Choo-Choo", person_id: 1>
# # ]
+ def count(column_name = nil, options = {})
+ @association.count(column_name, options)
+ end
##
- # :method: size
- #
- # :call-seq:
- # size()
- #
# Returns the size of the collection. If the collection hasn't been loaded,
# it executes a <tt>SELECT COUNT(*)</tt> query.
#
@@ -729,13 +707,11 @@ class CollectionProxy < Relation
# person.pets.size # => 3
# # Because the collection is already loaded, this will behave like
# # collection.size and no SQL count query is executed.
+ def size
+ @association.size
+ end
##
- # :method: length
- #
- # :call-seq:
- # length()
- #
# Returns the size of the collection calling +size+ on the target.
# If the collection has been already loaded, +length+ and +size+ are
# equivalent.
@@ -755,10 +731,11 @@ class CollectionProxy < Relation
# # #<Pet id: 2, name: "Spook", person_id: 1>,
# # #<Pet id: 3, name: "Choo-Choo", person_id: 1>
# # ]
+ def length
+ @association.length
+ end
##
- # :method: empty?
- #
# Returns +true+ if the collection is empty.
#
# class Person < ActiveRecord::Base
@@ -772,14 +749,11 @@ class CollectionProxy < Relation
#
# person.pets.count # => 0
# person.pets.empty? # => true
+ def empty?
+ @association.empty?
+ end
##
- # :method: any?
- #
- # :call-seq:
- # any?
- # any?{|item| block}
- #
# Returns +true+ if the collection is not empty.
#
# class Person < ActiveRecord::Base
@@ -809,14 +783,11 @@ class CollectionProxy < Relation
# pet.group == 'dogs'
# end
# # => true
+ def any?(&block)
+ @association.any?(&block)
+ end
##
- # :method: many?
- #
- # :call-seq:
- # many?
- # many?{|item| block}
- #
# Returns true if the collection has more than one record.
# Equivalent to <tt>collection.size > 1</tt>.
#
@@ -851,13 +822,11 @@ class CollectionProxy < Relation
# pet.group == 'cats'
# end
# # => true
+ def many?(&block)
+ @association.many?(&block)
+ end
##
- # :method: include?
- #
- # :call-seq:
- # include?(record)
- #
# Returns +true+ if the given object is present in the collection.
#
# class Person < ActiveRecord::Base
@@ -868,17 +837,8 @@ class CollectionProxy < Relation
#
# person.pets.include?(Pet.find(20)) # => true
# person.pets.include?(Pet.find(21)) # => false
- delegate :select, :find, :first, :last,
- :build, :create, :create!,
- :concat, :replace, :delete_all, :destroy_all, :delete, :destroy, :uniq,
- :sum, :count, :size, :length, :empty?,
- :any?, :many?, :include?,
- :to => :@association
-
- def initialize(association) #:nodoc:
- @association = association
- super association.klass, association.klass.arel_table
- merge! association.scoped
+ def include?(record)
+ @association.include?(record)
end
alias_method :new, :build

0 comments on commit 26d3e32

Please sign in to comment.