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
|
module ActiveRecord
module Associations
class AssociationScope #:nodoc:
def self.scope(association, connection)
INSTANCE.scope(association, connection)
end
def self.create(&block)
block ||= lambda { |val| val }
new(block)
end
def initialize(value_transformation)
@value_transformation = value_transformation
end
INSTANCE = create
def scope(association, connection)
klass = association.klass
reflection = association.reflection
scope = klass.unscoped
owner = association.owner
alias_tracker = AliasTracker.create connection, association.klass.table_name, klass.type_caster
chain_head, chain_tail = get_chain(reflection, association, alias_tracker)
scope.extending! Array(reflection.options[:extend])
add_constraints(scope, owner, klass, reflection, chain_head, chain_tail)
end
def join_type
Arel::Nodes::InnerJoin
end
def self.get_bind_values(owner, chain)
binds = []
last_reflection = chain.last
binds << last_reflection.join_id_for(owner)
if last_reflection.type
binds << owner.class.base_class.name
end
chain.each_cons(2).each do |reflection, next_reflection|
if reflection.type
binds << next_reflection.klass.base_class.name
end
end
binds
end
protected
attr_reader :value_transformation
private
def join(table, constraint)
table.create_join(table, table.create_on(constraint), join_type)
end
def last_chain_scope(scope, table, reflection, owner, association_klass)
join_keys = reflection.join_keys(association_klass)
key = join_keys.key
foreign_key = join_keys.foreign_key
value = transform_value(owner[foreign_key])
scope = scope.where(table.name => { key => value })
if reflection.type
polymorphic_type = transform_value(owner.class.base_class.name)
scope = scope.where(table.name => { reflection.type => polymorphic_type })
end
scope
end
def transform_value(value)
value_transformation.call(value)
end
def next_chain_scope(scope, table, reflection, association_klass, foreign_table, next_reflection)
join_keys = reflection.join_keys(association_klass)
key = join_keys.key
foreign_key = join_keys.foreign_key
constraint = table[key].eq(foreign_table[foreign_key])
if reflection.type
value = transform_value(next_reflection.klass.base_class.name)
scope = scope.where(table.name => { reflection.type => value })
end
scope = scope.joins(join(foreign_table, constraint))
end
class ReflectionProxy < SimpleDelegator # :nodoc:
attr_accessor :next
attr_reader :alias_name
def initialize(reflection, alias_name)
super(reflection)
@alias_name = alias_name
end
def all_includes; nil; end
end
def get_chain(reflection, association, tracker)
name = reflection.name
runtime_reflection = Reflection::RuntimeReflection.new(reflection, association)
previous_reflection = runtime_reflection
reflection.chain.drop(1).each do |refl|
alias_name = tracker.aliased_table_for(refl.table_name, refl.alias_candidate(name))
proxy = ReflectionProxy.new(refl, alias_name)
previous_reflection.next = proxy
previous_reflection = proxy
end
[runtime_reflection, previous_reflection]
end
def add_constraints(scope, owner, association_klass, refl, chain_head, chain_tail)
owner_reflection = chain_tail
table = owner_reflection.alias_name
scope = last_chain_scope(scope, table, owner_reflection, owner, association_klass)
reflection = chain_head
while reflection
table = reflection.alias_name
unless reflection == chain_tail
next_reflection = reflection.next
foreign_table = next_reflection.alias_name
scope = next_chain_scope(scope, table, reflection, association_klass, foreign_table, next_reflection)
end
# Exclude the scope of the association itself, because that
# was already merged in the #scope method.
reflection.constraints.each do |scope_chain_item|
item = eval_scope(reflection.klass, scope_chain_item, owner)
if scope_chain_item == refl.scope
scope.merge! item.except(:where, :includes)
end
reflection.all_includes do
scope.includes! item.includes_values
end
scope.unscope!(*item.unscope_values)
scope.where_clause += item.where_clause
scope.order_values |= item.order_values
end
reflection = reflection.next
end
scope
end
def eval_scope(klass, scope, owner)
klass.unscoped.instance_exec(owner, &scope)
end
end
end
end
|
