Split AssociationProxy into an Association class (and subclasses) which manages the association, and a CollectionProxy class which is *only* a proxy. Singular associations no longer have a proxy. See CHANGELOG for more.

1 files changed, 510 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/associations/collection_association.rb b/activerecord/lib/active_record/associations/collection_association.rb
new file mode 100644
index 0000000000..68631681e4
--- /dev/null
+++ b/activerecord/lib/active_record/associations/collection_association.rb
@@ -0,0 +1,510 @@
+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 CollectionAssociation < Association #:nodoc:
+      attr_reader :proxy
+
+      def initialize(owner, reflection)
+        # When scopes are created via method_missing on the proxy, they are stored so that
+        # any records fetched from the database are kept around for future use.
+        @scopes_cache = Hash.new do |hash, method|
+          hash[method] = { }
+        end
+
+        super
+
+        @proxy = CollectionProxy.new(self)
+      end
+
+      def reset
+        @loaded = false
+        @target = []
+        @scopes_cache.clear
+      end
+
+      def select(select = nil)
+        if block_given?
+          load_target.select.each { |e| yield e }
+        else
+          scoped.select(select)
+        end
+      end
+
+      def find(*args)
+        if @reflection.options[:finder_sql]
+          find_by_scan(*args)
+        else
+          scoped.find(*args)
+        end
+      end
+
+      def first(*args)
+        first_or_last(:first, *args)
+      end
+
+      def last(*args)
+        first_or_last(:last, *args)
+      end
+
+      def build(attributes = {}, &block)
+        build_or_create(attributes, :build, &block)
+      end
+
+      def create(attributes = {}, &block)
+        unless @owner.persisted?
+          raise ActiveRecord::RecordNotSaved, "You cannot call create unless the parent is saved"
+        end
+
+        build_or_create(attributes, :create, &block)
+      end
+
+      def create!(attrs = {}, &block)
+        record = create(attrs, &block)
+        Array.wrap(record).each(&:save!)
+        record
+      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)
+        result = true
+        load_target if @owner.new_record?
+
+        transaction do
+          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
+        end
+
+        result && records
+      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(load_target).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?
+          scoped.sum(*args) { |*block_args| yield(*block_args) }
+        else
+          scoped.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, options = {})
+        column_name, options = nil, column_name if column_name.is_a?(Hash)
+
+        if @reflection.options[:counter_sql] || @reflection.options[:finder_sql]
+          unless 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 @reflection.options[:uniq]
+            # This is needed because 'SELECT count(DISTINCT *)..' is not valid SQL.
+            column_name ||= @reflection.klass.primary_key
+            options.merge!(:distinct => true)
+          end
+
+          value = scoped.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)
+        delete_or_destroy(records, @reflection.options[:dependent])
+      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 @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?
+          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(collection = load_target)
+        seen = {}
+        collection.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
+
+        transaction do
+          delete(@target - other_array)
+
+          unless concat(other_array - @target)
+            @target = original_target
+            raise RecordNotSaved, "Failed to replace #{@reflection.name} because one or more of the " \
+                                  "new records could not be saved."
+          end
+        end
+      end
+
+      def include?(record)
+        if record.is_a?(@reflection.klass)
+          if record.new_record?
+            include_in_memory?(record)
+          else
+            load_target if @reflection.options[:finder_sql]
+            loaded? ? @target.include?(record) : scoped.exists?(record)
+          end
+        else
+          false
+        end
+      end
+
+      def cached_scope(method, args)
+        @scopes_cache[method][args] ||= scoped.readonly(nil).send(method, *args)
+      end
+
+      def association_scope
+        options = @reflection.options.slice(:order, :limit, :joins, :group, :having, :offset)
+        super.apply_finder_options(options)
+      end
+
+      def load_target
+        if find_target?
+          targets = []
+
+          begin
+            targets = find_target
+          rescue ActiveRecord::RecordNotFound
+            reset
+          end
+
+          @target = merge_target_lists(targets, @target)
+        end
+
+        loaded!
+        target
+      end
+
+      def add_to_target(record)
+        transaction do
+          callback(:before_add, record)
+          yield(record) if block_given?
+
+          if @reflection.options[:uniq] && index = @target.index(record)
+            @target[index] = record
+          else
+            @target << record
+          end
+
+          callback(:after_add, record)
+          set_inverse_instance(record)
+        end
+
+        record
+      end
+
+      private
+
+        def select_value
+          super || uniq_select_value
+        end
+
+        def uniq_select_value
+          @reflection.options[:uniq] && "DISTINCT #{@reflection.quoted_table_name}.*"
+        end
+
+        def custom_counter_sql
+          if @reflection.options[:counter_sql]
+            interpolate(@reflection.options[:counter_sql])
+          else
+            # replace the SELECT clause with COUNT(*), preserving any hints within /* ... */
+            interpolate(@reflection.options[:finder_sql]).sub(/SELECT\b(\/\*.*?\*\/ )?(.*)\bFROM\b/im) { "SELECT #{$1}COUNT(*) FROM" }
+          end
+        end
+
+        def custom_finder_sql
+          interpolate(@reflection.options[:finder_sql])
+        end
+
+        def find_target
+          records =
+            if @reflection.options[:finder_sql]
+              @reflection.klass.find_by_sql(custom_finder_sql)
+            else
+              find(:all)
+            end
+
+          records = @reflection.options[:uniq] ? uniq(records) : records
+          records.each { |record| set_inverse_instance(record) }
+          records
+        end
+
+        def merge_target_lists(loaded, existing)
+          return loaded if existing.empty?
+          return existing if loaded.empty?
+
+          loaded.map do |f|
+            i = existing.index(f)
+            if i
+              existing.delete_at(i).tap do |t|
+                keys = ["id"] + t.changes.keys + (f.attribute_names - t.attribute_names)
+                # FIXME: this call to attributes causes many NoMethodErrors
+                attributes = f.attributes
+                (attributes.keys - keys).each do |k|
+                  t.send("#{k}=", attributes[k])
+                end
+              end
+            else
+              f
+            end
+          end + existing
+        end
+
+        def build_or_create(attributes, method)
+          records = Array.wrap(attributes).map do |attrs|
+            record = build_record(attrs)
+
+            add_to_target(record) do
+              yield(record) if block_given?
+              insert_record(record) if method == :create
+            end
+          end
+
+          attributes.is_a?(Array) ? records : records.first
+        end
+
+        # Do the relevant stuff to insert the given record into the association collection.
+        def insert_record(record, validate = true)
+          raise NotImplementedError
+        end
+
+        def build_record(attributes)
+          @reflection.build_association(scoped.scope_for_create.merge(attributes))
+        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? }
+
+          transaction do
+            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
+        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 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? ||
+              @reflection.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.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
+        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) ? scoped : load_target
+          collection.send(type, *args)
+        end
+    end
+  end
+end