Organize Relation methods into separate modules

1 files changed, 120 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb
new file mode 100644
index 0000000000..7a1d6fc538
--- /dev/null
+++ b/activerecord/lib/active_record/relation/finder_methods.rb
@@ -0,0 +1,120 @@
+module ActiveRecord
+  module FinderMethods
+
+    def find(*ids, &block)
+      return to_a.find(&block) if block_given?
+
+      expects_array = ids.first.kind_of?(Array)
+      return ids.first if expects_array && ids.first.empty?
+
+      ids = ids.flatten.compact.uniq
+
+      case ids.size
+      when 0
+        raise RecordNotFound, "Couldn't find #{@klass.name} without an ID"
+      when 1
+        result = find_one(ids.first)
+        expects_array ? [ result ] : result
+      else
+        find_some(ids)
+      end
+    end
+
+    def exists?(id = nil)
+      relation = select("#{@klass.quoted_table_name}.#{@klass.primary_key}").limit(1)
+      relation = relation.where(@klass.primary_key => id) if id
+      relation.first ? true : false
+    end
+
+    def first
+      if loaded?
+        @records.first
+      else
+        @first ||= limit(1).to_a[0]
+      end
+    end
+
+    def last
+      if loaded?
+        @records.last
+      else
+        @last ||= reverse_order.limit(1).to_a[0]
+      end
+    end
+
+    protected
+
+    def find_by_attributes(match, attributes, *args)
+      conditions = attributes.inject({}) {|h, a| h[a] = args[attributes.index(a)]; h}
+      result = where(conditions).send(match.finder)
+
+      if match.bang? && result.blank?
+        raise RecordNotFound, "Couldn't find #{@klass.name} with #{conditions.to_a.collect {|p| p.join(' = ')}.join(', ')}"
+      else
+        result
+      end
+    end
+
+    def find_or_instantiator_by_attributes(match, attributes, *args)
+      guard_protected_attributes = false
+
+      if args[0].is_a?(Hash)
+        guard_protected_attributes = true
+        attributes_for_create = args[0].with_indifferent_access
+        conditions = attributes_for_create.slice(*attributes).symbolize_keys
+      else
+        attributes_for_create = conditions = attributes.inject({}) {|h, a| h[a] = args[attributes.index(a)]; h}
+      end
+
+      record = where(conditions).first
+
+      unless record
+        record = @klass.new { |r| r.send(:attributes=, attributes_for_create, guard_protected_attributes) }
+        yield(record) if block_given?
+        record.save if match.instantiator == :create
+      end
+
+      record
+    end
+
+    def find_one(id)
+      record = where(@klass.primary_key => id).first
+
+      unless record
+        conditions = where_clause(', ')
+        conditions = " [WHERE #{conditions}]" if conditions.present?
+        raise RecordNotFound, "Couldn't find #{@klass.name} with ID=#{id}#{conditions}"
+      end
+
+      record
+    end
+
+    def find_some(ids)
+      result = where(@klass.primary_key => ids).all
+
+      expected_size =
+        if @relation.taken && ids.size > @relation.taken
+          @relation.taken
+        else
+          ids.size
+        end
+
+      # 11 ids with limit 3, offset 9 should give 2 results.
+      if @relation.skipped && (ids.size - @relation.skipped < expected_size)
+        expected_size = ids.size - @relation.skipped
+      end
+
+      if result.size == expected_size
+        result
+      else
+        conditions = where_clause(', ')
+        conditions = " [WHERE #{conditions}]" if conditions.present?
+
+        error = "Couldn't find all #{@klass.name.pluralize} with IDs "
+        error << "(#{ids.join(", ")})#{conditions} (found #{result.size} results, but was looking for #{expected_size})"
+        raise RecordNotFound, error
+      end
+    end
+
+  end
+end