Merge pull request #39612 from kamipo/faster_attributes

PERF: 45% faster attributes for readonly usage

activemodel/lib/active_model/attribute.rb

@@ -5,16 +5,16 @@ require "active_support/core_ext/object/duplicable"
 module ActiveModel
   class Attribute # :nodoc:
     class << self
-      def from_database(name, value, type)
-        FromDatabase.new(name, value, type)
+      def from_database(name, value_before_type_cast, type, value = nil)
+        FromDatabase.new(name, value_before_type_cast, type, nil, value)
       end
 
-      def from_user(name, value, type, original_attribute = nil)
-        FromUser.new(name, value, type, original_attribute)
+      def from_user(name, value_before_type_cast, type, original_attribute = nil)
+        FromUser.new(name, value_before_type_cast, type, original_attribute)
       end
 
-      def with_cast_value(name, value, type)
-        WithCastValue.new(name, value, type)
+      def with_cast_value(name, value_before_type_cast, type)
+        WithCastValue.new(name, value_before_type_cast, type)
       end
 
       def null(name)
@@ -30,11 +30,12 @@ module ActiveModel
 
     # This method should not be called directly.
     # Use #from_database or #from_user
-    def initialize(name, value_before_type_cast, type, original_attribute = nil)
+    def initialize(name, value_before_type_cast, type, original_attribute = nil, value = nil)
       @name = name
       @value_before_type_cast = value_before_type_cast
       @type = type
       @original_attribute = original_attribute
+      @value = value unless value.nil?
     end
 
     def value

activemodel/lib/active_model/attribute_set.rb

@@ -13,11 +13,11 @@ module ActiveModel
     end
 
     def [](name)
-      attributes[name] || Attribute.null(name)
+      @attributes[name] || default_attribute(name)
     end
 
     def []=(name, value)
-      attributes[name] = value
+      @attributes[name] = value
     end
 
     def values_before_type_cast
@@ -25,9 +25,9 @@ module ActiveModel
     end
 
     def to_hash
-      initialized_attributes.transform_values(&:value)
+      keys.index_with { |name| self[name].value }
     end
-    alias_method :to_h, :to_hash
+    alias :to_h :to_hash
 
     def key?(name)
       attributes.key?(name) && self[name].initialized?
@@ -42,38 +42,36 @@ module ActiveModel
     end
 
     def write_from_database(name, value)
-      attributes[name] = self[name].with_value_from_database(value)
+      @attributes[name] = self[name].with_value_from_database(value)
     end
 
     def write_from_user(name, value)
       raise FrozenError, "can't modify frozen attributes" if frozen?
-      attributes[name] = self[name].with_value_from_user(value)
+      @attributes[name] = self[name].with_value_from_user(value)
       value
     end
 
     def write_cast_value(name, value)
-      attributes[name] = self[name].with_cast_value(value)
+      @attributes[name] = self[name].with_cast_value(value)
       value
     end
 
     def freeze
-      @attributes.freeze
+      attributes.freeze
       super
     end
 
     def deep_dup
-      self.class.allocate.tap do |copy|
-        copy.instance_variable_set(:@attributes, attributes.deep_dup)
-      end
+      AttributeSet.new(attributes.deep_dup)
     end
 
     def initialize_dup(_)
-      @attributes = attributes.dup
+      @attributes = @attributes.dup
       super
     end
 
     def initialize_clone(_)
-      @attributes = attributes.clone
+      @attributes = @attributes.clone
       super
     end
 
@@ -84,7 +82,7 @@ module ActiveModel
     end
 
     def accessed
-      attributes.select { |_, attr| attr.has_been_read? }.keys
+      attributes.each_key.select { |name| self[name].has_been_read? }
     end
 
     def map(&block)
@@ -100,8 +98,8 @@ module ActiveModel
       attr_reader :attributes
 
     private
-      def initialized_attributes
-        attributes.select { |_, attr| attr.initialized? }
+      def default_attribute(name)
+        Attribute.null(name)
       end
   end
 end

activemodel/lib/active_model/attribute_set/builder.rb

@@ -13,14 +13,86 @@ module ActiveModel
       end
 
       def build_from_database(values = {}, additional_types = {})
-        attributes = LazyAttributeHash.new(types, values, additional_types, default_attributes)
-        AttributeSet.new(attributes)
+        LazyAttributeSet.new(values, types, additional_types, default_attributes)
       end
     end
   end
 
+  class LazyAttributeSet < AttributeSet # :nodoc:
+    def initialize(values, types, additional_types, default_attributes, attributes = {})
+      super(attributes)
+      @values = values
+      @types = types
+      @additional_types = additional_types
+      @default_attributes = default_attributes
+      @casted_values = {}
+      @materialized = false
+    end
+
+    def key?(name)
+      (values.key?(name) || types.key?(name) || @attributes.key?(name)) && self[name].initialized?
+    end
+
+    def keys
+      keys = values.keys | types.keys | @attributes.keys
+      keys.keep_if { |name| self[name].initialized? }
+    end
+
+    def fetch_value(name, &block)
+      if attr = @attributes[name]
+        return attr.value(&block)
+      end
+
+      @casted_values.fetch(name) do
+        value_present = true
+        value = values.fetch(name) { value_present = false }
+
+        if value_present
+          type = additional_types.fetch(name, types[name])
+          @casted_values[name] = type.deserialize(value)
+        else
+          attr = default_attribute(name, value_present, value)
+          attr.value(&block)
+        end
+      end
+    end
+
+    protected
+      def attributes
+        unless @materialized
+          values.each_key { |key| self[key] }
+          types.each_key { |key| self[key] }
+          @materialized = true
+        end
+        @attributes
+      end
+
+    private
+      attr_reader :values, :types, :additional_types, :default_attributes
+
+      def default_attribute(
+        name,
+        value_present = true,
+        value = values.fetch(name) { value_present = false }
+      )
+        type = additional_types.fetch(name, types[name])
+
+        if value_present
+          @attributes[name] = Attribute.from_database(name, value, type, @casted_values[name])
+        elsif types.key?(name)
+          if attr = default_attributes[name]
+            @attributes[name] = attr.dup
+          else
+            @attributes[name] = Attribute.uninitialized(name, type)
+          end
+        else
+          Attribute.null(name)
+        end
+      end
+  end
+
   class LazyAttributeHash # :nodoc:
-    delegate :transform_values, :each_key, :each_value, :fetch, :except, to: :materialize
+    delegate :transform_values, :each_value, :fetch, :except, to: :materialize
 
     def initialize(types, values, additional_types, default_attributes, delegate_hash = {})
       @types = types
@@ -54,14 +126,9 @@ module ActiveModel
       super
     end
 
-    def select
+    def each_key(&block)
       keys = types.keys | values.keys | delegate_hash.keys
-      keys.each_with_object({}) do |key, hash|
-        attribute = self[key]
-        if yield(key, attribute)
-          hash[key] = attribute
-        end
-      end
+      keys.each(&block)
     end
 
     def ==(other)

activemodel/test/cases/attribute_set_test.rb

@@ -219,6 +219,12 @@ module ActiveModel
 
     test "marshalling dump/load legacy materialized attribute hash" do
       builder = AttributeSet::Builder.new(foo: Type::String.new)
+
+      def builder.build_from_database(values = {}, additional_types = {})
+        attributes = LazyAttributeHash.new(types, values, additional_types, default_attributes)
+        AttributeSet.new(attributes)
+      end
+
       attributes = builder.build_from_database(foo: "1")
 
       attributes.instance_variable_get(:@attributes).instance_eval do