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
|
module ActiveRecord
class Attribute # :nodoc:
class << self
def from_database(name, value, type)
FromDatabase.new(name, value, type)
end
def from_user(name, value, type)
FromUser.new(name, value, type)
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)
@name = name
@value_before_type_cast = value_before_type_cast
@type = type
end
def value
# `defined?` is cheaper than `||=` when we get back falsy values
@value = original_value unless defined?(@value)
@value
end
def original_value
type_cast(value_before_type_cast)
end
def value_for_database
type.type_cast_for_database(value)
end
def changed_from?(old_value)
type.changed?(old_value, value, value_before_type_cast)
end
def changed_in_place_from?(old_value)
has_been_read? && type.changed_in_place?(old_value, value)
end
def with_value_from_user(value)
self.class.from_user(name, value, type)
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 type_cast(*)
raise NotImplementedError
end
def initialized?
true
end
def came_from_user?
false
end
def ==(other)
self.class == other.class &&
name == other.name &&
value_before_type_cast == other.value_before_type_cast &&
type == other.type
end
protected
def initialize_dup(other)
if defined?(@value) && @value.duplicable?
@value = @value.dup
end
end
private
def has_been_read?
defined?(@value)
end
class FromDatabase < Attribute # :nodoc:
def type_cast(value)
type.type_cast_from_database(value)
end
end
class FromUser < Attribute # :nodoc:
def type_cast(value)
type.type_cast_from_user(value)
end
def came_from_user?
true
end
end
class WithCastValue < Attribute # :nodoc:
def type_cast(value)
value
end
def changed_in_place_from?(old_value)
false
end
end
class Null < Attribute # :nodoc:
def initialize(name)
super(name, nil, Type::Value.new)
end
def value
nil
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:
def initialize(name, type)
super(name, nil, type)
end
def value
if block_given?
yield name
end
end
def value_for_database
end
def initialized?
false
end
end
private_constant :FromDatabase, :FromUser, :Null, :Uninitialized
end
end
|
