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
|
module ActiveRecord
# Track unsaved attribute changes.
#
# A newly instantiated object is unchanged:
# person = Person.find_by_name('uncle bob')
# person.changed? # => false
#
# Change the name:
# person.name = 'Bob'
# person.changed? # => true
# person.name_changed? # => true
# person.name_was # => 'uncle bob'
# person.name_change # => ['uncle bob', 'Bob']
# person.name = 'Bill'
# person.name_change # => ['uncle bob', 'Bill']
#
# Save the changes:
# person.save
# person.changed? # => false
# person.name_changed? # => false
#
# Assigning the same value leaves the attribute unchanged:
# person.name = 'Bill'
# person.name_changed? # => false
# person.name_change # => nil
#
# Which attributes have changed?
# person.name = 'bob'
# person.changed # => ['name']
# person.changes # => { 'name' => ['Bill', 'bob'] }
#
# Before modifying an attribute in-place:
# person.name_will_change!
# person.name << 'by'
# person.name_change # => ['uncle bob', 'uncle bobby']
module Dirty
extend ActiveSupport::DependencyModule
DIRTY_SUFFIXES = ['_changed?', '_change', '_will_change!', '_was']
included do
attribute_method_suffix *DIRTY_SUFFIXES
alias_method_chain :write_attribute, :dirty
alias_method_chain :save, :dirty
alias_method_chain :save!, :dirty
alias_method_chain :update, :dirty
alias_method_chain :reload, :dirty
superclass_delegating_accessor :partial_updates
self.partial_updates = true
end
# Do any attributes have unsaved changes?
# person.changed? # => false
# person.name = 'bob'
# person.changed? # => true
def changed?
!changed_attributes.empty?
end
# List of attributes with unsaved changes.
# person.changed # => []
# person.name = 'bob'
# person.changed # => ['name']
def changed
changed_attributes.keys
end
# Map of changed attrs => [original value, new value].
# person.changes # => {}
# person.name = 'bob'
# person.changes # => { 'name' => ['bill', 'bob'] }
def changes
changed.inject({}) { |h, attr| h[attr] = attribute_change(attr); h }
end
# Attempts to +save+ the record and clears changed attributes if successful.
def save_with_dirty(*args) #:nodoc:
if status = save_without_dirty(*args)
changed_attributes.clear
end
status
end
# Attempts to <tt>save!</tt> the record and clears changed attributes if successful.
def save_with_dirty!(*args) #:nodoc:
status = save_without_dirty!(*args)
changed_attributes.clear
status
end
# <tt>reload</tt> the record and clears changed attributes.
def reload_with_dirty(*args) #:nodoc:
record = reload_without_dirty(*args)
changed_attributes.clear
record
end
private
# Map of change <tt>attr => original value</tt>.
def changed_attributes
@changed_attributes ||= {}
end
# Handle <tt>*_changed?</tt> for +method_missing+.
def attribute_changed?(attr)
changed_attributes.include?(attr)
end
# Handle <tt>*_change</tt> for +method_missing+.
def attribute_change(attr)
[changed_attributes[attr], __send__(attr)] if attribute_changed?(attr)
end
# Handle <tt>*_was</tt> for +method_missing+.
def attribute_was(attr)
attribute_changed?(attr) ? changed_attributes[attr] : __send__(attr)
end
# Handle <tt>*_will_change!</tt> for +method_missing+.
def attribute_will_change!(attr)
changed_attributes[attr] = clone_attribute_value(:read_attribute, attr)
end
# Wrap write_attribute to remember original attribute value.
def write_attribute_with_dirty(attr, value)
attr = attr.to_s
# The attribute already has an unsaved change.
if changed_attributes.include?(attr)
old = changed_attributes[attr]
changed_attributes.delete(attr) unless field_changed?(attr, old, value)
else
old = clone_attribute_value(:read_attribute, attr)
changed_attributes[attr] = old if field_changed?(attr, old, value)
end
# Carry on.
write_attribute_without_dirty(attr, value)
end
def update_with_dirty
if partial_updates?
# Serialized attributes should always be written in case they've been
# changed in place.
update_without_dirty(changed | self.class.serialized_attributes.keys)
else
update_without_dirty
end
end
def field_changed?(attr, old, value)
if column = column_for_attribute(attr)
if column.number? && column.null && (old.nil? || old == 0) && value.blank?
# For nullable numeric columns, NULL gets stored in database for blank (i.e. '') values.
# Hence we don't record it as a change if the value changes from nil to ''.
# If an old value of 0 is set to '' we want this to get changed to nil as otherwise it'll
# be typecast back to 0 (''.to_i => 0)
value = nil
else
value = column.type_cast(value)
end
end
old != value
end
module ClassMethods
def self.extended(base)
class << base
alias_method_chain :alias_attribute, :dirty
end
end
def alias_attribute_with_dirty(new_name, old_name)
alias_attribute_without_dirty(new_name, old_name)
DIRTY_SUFFIXES.each do |suffix|
module_eval <<-STR, __FILE__, __LINE__+1
def #{new_name}#{suffix}; self.#{old_name}#{suffix}; end # def subject_changed?; self.title_changed?; end
STR
end
end
end
end
end
|
