Skip to content
This repository

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Octocat-spinner-32-eaf2f5

Cannot retrieve contributors at this time

file 584 lines (505 sloc) 19.472 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583
module ActiveRecord
  module Associations
    # = Active Record Association Collection
    #
    # CollectionAssociation is an abstract class that provides common stuff to
    # ease the implementation of association proxies that represent
    # collections. See the class hierarchy in AssociationProxy.
    #
    # CollectionAssociation:
    # HasAndBelongsToManyAssociation => has_and_belongs_to_many
    # HasManyAssociation => has_many
    # HasManyThroughAssociation + ThroughAssociation => has_many :through
    #
    # CollectionAssociation class provides common methods to the collections
    # defined by +has_and_belongs_to_many+, +has_many+ or +has_many+ with
    # +:through association+ option.
    #
    # 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 CollectionAssociation < Association #:nodoc:

      # Implements the reader method, e.g. foo.items for Foo.has_many :items
      def reader(force_reload = false)
        if force_reload
          klass.uncached { reload }
        elsif stale_target?
          reload
        end

        CollectionProxy.new(self)
      end

      # Implements the writer method, e.g. foo.items= for Foo.has_many :items
      def writer(records)
        replace(records)
      end

      # Implements the ids reader method, e.g. foo.item_ids for Foo.has_many :items
      def ids_reader
        if loaded? || options[:finder_sql]
          load_target.map do |record|
            record.send(reflection.association_primary_key)
          end
        else
          column = "#{reflection.quoted_table_name}.#{reflection.association_primary_key}"
          scope.pluck(column)
        end
      end

      # Implements the ids writer method, e.g. foo.item_ids= for Foo.has_many :items
      def ids_writer(ids)
        pk_column = reflection.primary_key_column
        ids = Array(ids).reject { |id| id.blank? }
        ids.map! { |i| pk_column.type_cast(i) }
        replace(klass.find(ids).index_by { |r| r.id }.values_at(*ids))
      end

      def reset
        super
        @target = []
      end

      def select(select = nil)
        if block_given?
          load_target.select.each { |e| yield e }
        else
          scope.select(select)
        end
      end

      def find(*args)
        if block_given?
          load_target.find(*args) { |*block_args| yield(*block_args) }
        else
          if options[:finder_sql]
            find_by_scan(*args)
          else
            scope.find(*args)
          end
        end
      end

      def first(*args)
        first_or_last(:first, *args)
      end

      def last(*args)
        first_or_last(:last, *args)
      end

      def build(attributes = {}, &block)
        if attributes.is_a?(Array)
          attributes.collect { |attr| build(attr, &block) }
        else
          add_to_target(build_record(attributes)) do |record|
            yield(record) if block_given?
          end
        end
      end

      def create(attributes = {}, &block)
        create_record(attributes, &block)
      end

      def create!(attributes = {}, &block)
        create_record(attributes, true, &block)
      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 concat(*records)
        load_target if owner.new_record?

        if owner.new_record?
          concat_records(records)
        else
          transaction { concat_records(records) }
        end
      end

      # 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
        delete(:all).tap do
          reset
          loaded!
        end
      end

      # Destroy all the records from this association.
      #
      # See destroy for more info.
      def destroy_all
        destroy(load_target).tap do
          reset
          loaded!
        end
      end

      # Calculate sum using SQL, not Enumerable.
      def sum(*args)
        if block_given?
          scope.sum(*args) { |*block_args| yield(*block_args) }
        else
          scope.sum(*args)
        end
      end

      # Count all records using SQL. If the +:counter_sql+ or +:finder_sql+ option is set for the
      # association, it will be used for the query. Otherwise, construct options and pass them with
      # scope to the target class's +count+.
      def count(column_name = nil, count_options = {})
        return 0 if owner.new_record?

        column_name, count_options = nil, column_name if column_name.is_a?(Hash)

        if options[:counter_sql] || options[:finder_sql]
          unless count_options.blank?
            raise ArgumentError, "If finder_sql/counter_sql is used then options cannot be passed"
          end

          reflection.klass.count_by_sql(custom_counter_sql)
        else
          if association_scope.uniq_value
            # This is needed because 'SELECT count(DISTINCT *)..' is not valid SQL.
            column_name ||= reflection.klass.primary_key
            count_options[:distinct] = true
          end

          value = scope.count(column_name, count_options)

          limit = options[:limit]
          offset = 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)
        dependent = options[:dependent]

        if records.first == :all
          if loaded? || dependent == :destroy
            delete_or_destroy(load_target, dependent)
          else
            delete_records(:all, dependent)
          end
        else
          records = find(records) if records.any? { |record| record.kind_of?(Fixnum) || record.kind_of?(String) }
          delete_or_destroy(records, dependent)
        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) }
        delete_or_destroy(records, :destroy)
      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 !find_target? || loaded?
          if association_scope.uniq_value
            target.uniq.size
          else
            target.size
          end
        elsif !loaded? && !association_scope.group_values.empty?
          load_target.size
        elsif !loaded? && !association_scope.uniq_value && 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

      # Returns true if the collection is empty.
      #
      # If the collection has been loaded or the <tt>:counter_sql</tt> option
      # is provided, it is equivalent to <tt>collection.size.zero?</tt>. If the
      # collection has not been loaded, it is equivalent to
      # <tt>collection.exists?</tt>. If the collection has not already been
      # loaded and you are going to fetch the records anyway it is better to
      # check <tt>collection.length.zero?</tt>.
      def empty?
        if loaded? || options[:counter_sql]
          size.zero?
        else
          !scope.exists?
        end
      end

      # Returns true if the collections is not empty.
      # Equivalent to +!collection.empty?+.
      def any?
        if block_given?
          load_target.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?
          load_target.many? { |*block_args| yield(*block_args) }
        else
          size > 1
        end
      end

      def uniq
        seen = {}
        load_target.find_all do |record|
          seen[record.id] = true unless seen.key?(record.id)
        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) }
        original_target = load_target.dup

        if owner.new_record?
          replace_records(other_array, original_target)
        else
          transaction { replace_records(other_array, original_target) }
        end
      end

      def include?(record)
        if record.is_a?(reflection.klass)
          if record.new_record?
            include_in_memory?(record)
          else
            load_target if options[:finder_sql]
            loaded? ? target.include?(record) : scope.exists?(record)
          end
        else
          false
        end
      end

      def load_target
        if find_target?
          @target = merge_target_lists(find_target, target)
        end

        loaded!
        target
      end

      def add_to_target(record)
        callback(:before_add, record)
        yield(record) if block_given?

        if association_scope.uniq_value && index = @target.index(record)
          @target[index] = record
        else
          @target << record
        end

        callback(:after_add, record)
        set_inverse_instance(record)

        record
      end

      private

        def custom_counter_sql
          if options[:counter_sql]
            interpolate(options[:counter_sql])
          else
            # replace the SELECT clause with COUNT(SELECTS), preserving any hints within /* ... */
            interpolate(options[:finder_sql]).sub(/SELECT\b(\/\*.*?\*\/ )?(.*)\bFROM\b/im) do
              count_with = $2.to_s
              count_with = '*' if count_with.blank? || count_with =~ /,/ || count_with =~ /\.\*/
              "SELECT #{$1}COUNT(#{count_with}) FROM"
            end
          end
        end

        def custom_finder_sql
          interpolate(options[:finder_sql])
        end

        def find_target
          records =
            if options[:finder_sql]
              reflection.klass.find_by_sql(custom_finder_sql)
            else
              scope.to_a
            end

          records.each { |record| set_inverse_instance(record) }
          records
        end

        # We have some records loaded from the database (persisted) and some that are
        # in-memory (memory). The same record may be represented in the persisted array
        # and in the memory array.
        #
        # So the task of this method is to merge them according to the following rules:
        #
        # * The final array must not have duplicates
        # * The order of the persisted array is to be preserved
        # * Any changes made to attributes on objects in the memory array are to be preserved
        # * Otherwise, attributes should have the value found in the database
        def merge_target_lists(persisted, memory)
          return persisted if memory.empty?
          return memory if persisted.empty?

          persisted.map! do |record|
            if mem_record = memory.delete(record)

              ((record.attribute_names & mem_record.attribute_names) - mem_record.changes.keys).each do |name|
                mem_record[name] = record[name]
              end

              mem_record
            else
              record
            end
          end

          persisted + memory
        end

        def create_record(attributes, raise = false, &block)
          unless owner.persisted?
            raise ActiveRecord::RecordNotSaved, "You cannot call create unless the parent is saved"
          end

          if attributes.is_a?(Array)
            attributes.collect { |attr| create_record(attr, raise, &block) }
          else
            transaction do
              add_to_target(build_record(attributes)) do |record|
                yield(record) if block_given?
                insert_record(record, true, raise)
              end
            end
          end
        end

        # Do the relevant stuff to insert the given record into the association collection.
        def insert_record(record, validate = true, raise = false)
          raise NotImplementedError
        end

        def create_scope
          scope.scope_for_create.stringify_keys
        end

        def delete_or_destroy(records, method)
          records = records.flatten
          records.each { |record| raise_on_type_mismatch(record) }
          existing_records = records.reject { |r| r.new_record? }

          if existing_records.empty?
            remove_records(existing_records, records, method)
          else
            transaction { remove_records(existing_records, records, method) }
          end
        end

        def remove_records(existing_records, records, method)
          records.each { |record| callback(:before_remove, record) }

          delete_records(existing_records, method) if existing_records.any?
          records.each { |record| target.delete(record) }

          records.each { |record| callback(:after_remove, record) }
        end

        # Delete the given records from the association, using one of the methods :destroy,
        # :delete_all or :nullify (or nil, in which case a default is used).
        def delete_records(records, method)
          raise NotImplementedError
        end

        def replace_records(new_target, original_target)
          delete(target - new_target)

          unless concat(new_target - target)
            @target = original_target
            raise RecordNotSaved, "Failed to replace #{reflection.name} because one or more of the " \
                                  "new records could not be saved."
          end

          target
        end

        def concat_records(records)
          result = true

          records.flatten.each do |record|
            raise_on_type_mismatch(record)
            add_to_target(record) do |r|
              result &&= insert_record(record) unless owner.new_record?
            end
          end

          result && records
        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.send(full_callback_name.to_sym) || []
        end

        # Should we deal with assoc.first or assoc.last by issuing an independent query to
        # the database, or by getting the target, and then taking the first/last item from that?
        #
        # If the args is just a non-empty options hash, go to the database.
        #
        # Otherwise, go to the database only if none of the following are true:
        # * target already loaded
        # * owner is new record
        # * custom :finder_sql exists
        # * target contains new or changed record(s)
        # * the first arg is an integer (which indicates the number of records to be returned)
        def fetch_first_or_last_using_find?(args)
          if args.first.is_a?(Hash)
            true
          else
            !(loaded? ||
              owner.new_record? ||
              options[:finder_sql] ||
              target.any? { |record| record.new_record? || record.changed? } ||
              args.first.kind_of?(Integer))
          end
        end

        def include_in_memory?(record)
          if reflection.is_a?(ActiveRecord::Reflection::ThroughReflection)
            owner.send(reflection.through_reflection.name).any? { |source|
              target = source.send(reflection.source_reflection.name)
              target.respond_to?(:include?) ? target.include?(record) : target == record
            } || target.include?(record)
          else
            target.include?(record)
          end
        end

        # If using a custom finder_sql, #find scans the entire collection.
        def find_by_scan(*args)
          expects_array = args.first.kind_of?(Array)
          ids = args.flatten.compact.map{ |arg| arg.to_i }.uniq

          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
        end

        # Fetches the first/last using SQL if possible, otherwise from the target array.
        def first_or_last(type, *args)
          args.shift if args.first.is_a?(Hash) && args.first.empty?

          collection = fetch_first_or_last_using_find?(args) ? scope : load_target
          collection.send(type, *args).tap {|it| set_inverse_instance it }
        end
    end
  end
end
Something went wrong with that request. Please try again.