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
|
# frozen_string_literal: true
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)
end
def from_user(name, value, type, original_attribute = nil)
FromUser.new(name, value, type, original_attribute)
end
def with_cast_value(name, value, type)
WithCastValue.new(name, value, type)
end
def null(name)
Null.new(name)
end
def uninitialized(name, type)
Uninitialized.new(name, type)
end
end
attr_reader :name, :value_before_type_cast, :type
# This method should not be called directly.
# Use #from_database or #from_user
def initialize(name, value_before_type_cast, type, original_attribute = nil)
@name = name
@value_before_type_cast = value_before_type_cast
@type = type
@original_attribute = original_attribute
end
def value
# `defined?` is cheaper than `||=` when we get back falsy values
@value = type_cast(value_before_type_cast) unless defined?(@value)
@value
end
def original_value
if assigned?
original_attribute.original_value
else
type_cast(value_before_type_cast)
end
end
def value_for_database
type.serialize(value)
end
def changed?
changed_from_assignment? || changed_in_place?
end
def changed_in_place?
has_been_read? && type.changed_in_place?(original_value_for_database, value)
end
def forgetting_assignment
with_value_from_database(value_for_database)
end
def with_value_from_user(value)
type.assert_valid_value(value)
self.class.from_user(name, value, type, original_attribute || self)
end
def with_value_from_database(value)
self.class.from_database(name, value, type)
end
def with_cast_value(value)
self.class.with_cast_value(name, value, type)
end
def with_type(type)
if changed_in_place?
with_value_from_user(value).with_type(type)
else
self.class.new(name, value_before_type_cast, type, original_attribute)
end
end
def type_cast(*)
raise NotImplementedError
end
def initialized?
true
end
def came_from_user?
false
end
def has_been_read?
defined?(@value)
end
def ==(other)
self.class == other.class &&
name == other.name &&
value_before_type_cast == other.value_before_type_cast &&
type == other.type
end
alias eql? ==
def hash
[self.class, name, value_before_type_cast, type].hash
end
def init_with(coder)
@name = coder["name"]
@value_before_type_cast = coder["value_before_type_cast"]
@type = coder["type"]
@original_attribute = coder["original_attribute"]
@value = coder["value"] if coder.map.key?("value")
end
def encode_with(coder)
coder["name"] = name
coder["value_before_type_cast"] = value_before_type_cast unless value_before_type_cast.nil?
coder["type"] = type if type
coder["original_attribute"] = original_attribute if original_attribute
coder["value"] = value if defined?(@value)
end
protected
attr_reader :original_attribute
alias_method :assigned?, :original_attribute
def original_value_for_database
if assigned?
original_attribute.original_value_for_database
else
_original_value_for_database
end
end
private
def initialize_dup(other)
if defined?(@value) && @value.duplicable?
@value = @value.dup
end
end
def changed_from_assignment?
assigned? && type.changed?(original_value, value, value_before_type_cast)
end
def _original_value_for_database
type.serialize(original_value)
end
class FromDatabase < Attribute # :nodoc:
def type_cast(value)
type.deserialize(value)
end
def _original_value_for_database
value_before_type_cast
end
end
class FromUser < Attribute # :nodoc:
def type_cast(value)
type.cast(value)
end
def came_from_user?
!type.value_constructed_by_mass_assignment?(value_before_type_cast)
end
end
class WithCastValue < Attribute # :nodoc:
def type_cast(value)
value
end
def changed_in_place?
false
end
end
class Null < Attribute # :nodoc:
def initialize(name)
super(name, nil, Type.default_value)
end
def type_cast(*)
nil
end
def with_type(type)
self.class.with_cast_value(name, nil, type)
end
def with_value_from_database(value)
raise ActiveModel::MissingAttributeError, "can't write unknown attribute `#{name}`"
end
alias_method :with_value_from_user, :with_value_from_database
end
class Uninitialized < Attribute # :nodoc:
UNINITIALIZED_ORIGINAL_VALUE = Object.new
def initialize(name, type)
super(name, nil, type)
end
def value
if block_given?
yield name
end
end
def original_value
UNINITIALIZED_ORIGINAL_VALUE
end
def value_for_database
end
def initialized?
false
end
def with_type(type)
self.class.new(name, type)
end
end
private_constant :FromDatabase, :FromUser, :Null, :Uninitialized, :WithCastValue
end
end
|
