aboutsummaryrefslogtreecommitdiffstats
path: root/activemodel/lib/active_model/attribute_mutation_tracker.rb
blob: d8cd48a53b4c6e8182e00395647f092cb20720f7 (plain) (blame)
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
# frozen_string_literal: true

require "active_support/core_ext/hash/indifferent_access"
require "active_support/core_ext/object/duplicable"

module ActiveModel
  class AttributeMutationTracker # :nodoc:
    OPTION_NOT_GIVEN = Object.new

    def initialize(attributes, forced_changes = Set.new)
      @attributes = attributes
      @forced_changes = forced_changes
    end

    def changed_attribute_names
      attr_names.select { |attr_name| changed?(attr_name) }
    end

    def changed_values
      attr_names.each_with_object({}.with_indifferent_access) do |attr_name, result|
        if changed?(attr_name)
          result[attr_name] = original_value(attr_name)
        end
      end
    end

    def changes
      attr_names.each_with_object({}.with_indifferent_access) do |attr_name, result|
        if change = change_to_attribute(attr_name)
          result.merge!(attr_name => change)
        end
      end
    end

    def change_to_attribute(attr_name)
      if changed?(attr_name)
        [original_value(attr_name), fetch_value(attr_name)]
      end
    end

    def any_changes?
      attr_names.any? { |attr| changed?(attr) }
    end

    def changed?(attr_name, from: OPTION_NOT_GIVEN, to: OPTION_NOT_GIVEN)
      attribute_changed?(attr_name) &&
        (OPTION_NOT_GIVEN == from || original_value(attr_name) == from) &&
        (OPTION_NOT_GIVEN == to || fetch_value(attr_name) == to)
    end

    def changed_in_place?(attr_name)
      attributes[attr_name].changed_in_place?
    end

    def forget_change(attr_name)
      attributes[attr_name] = attributes[attr_name].forgetting_assignment
      forced_changes.delete(attr_name)
    end

    def original_value(attr_name)
      attributes[attr_name].original_value
    end

    def force_change(attr_name)
      forced_changes << attr_name
    end

    private
      attr_reader :attributes, :forced_changes

      def attr_names
        attributes.keys
      end

      def attribute_changed?(attr_name)
        forced_changes.include?(attr_name) || !!attributes[attr_name].changed?
      end

      def fetch_value(attr_name)
        attributes.fetch_value(attr_name)
      end
  end

  class ForcedMutationTracker < AttributeMutationTracker # :nodoc:
    def initialize(attributes, forced_changes = {})
      super
      @finalized_changes = nil
    end

    def changed_in_place?(attr_name)
      false
    end

    def change_to_attribute(attr_name)
      if finalized_changes&.include?(attr_name)
        finalized_changes[attr_name].dup
      else
        super
      end
    end

    def forget_change(attr_name)
      forced_changes.delete(attr_name)
    end

    def original_value(attr_name)
      if changed?(attr_name)
        forced_changes[attr_name]
      else
        fetch_value(attr_name)
      end
    end

    def force_change(attr_name)
      forced_changes[attr_name] = clone_value(attr_name) unless attribute_changed?(attr_name)
    end

    def finalize_changes
      @finalized_changes = changes
    end

    private
      attr_reader :finalized_changes

      def attr_names
        forced_changes.keys
      end

      def attribute_changed?(attr_name)
        forced_changes.include?(attr_name)
      end

      def fetch_value(attr_name)
        attributes.send(:_read_attribute, attr_name)
      end

      def clone_value(attr_name)
        value = fetch_value(attr_name)
        value.duplicable? ? value.clone : value
      rescue TypeError, NoMethodError
        value
      end
  end

  class NullMutationTracker # :nodoc:
    include Singleton

    def changed_attribute_names
      []
    end

    def changed_values
      {}
    end

    def changes
      {}
    end

    def change_to_attribute(attr_name)
    end

    def any_changes?
      false
    end

    def changed?(attr_name, **)
      false
    end

    def changed_in_place?(attr_name)
      false
    end

    def original_value(attr_name)
    end
  end
end