blob: 85343040db2f67d17468fdd8c1fadb8570c7850b (
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
|
module ActiveRecord
module Associations
class Preloader
class Association #:nodoc:
attr_reader :owners, :reflection, :preload_scope, :model, :klass
attr_reader :preloaded_records
def initialize(klass, owners, reflection, preload_scope)
@klass = klass
@owners = owners
@reflection = reflection
@preload_scope = preload_scope
@model = owners.first && owners.first.class
@preloaded_records = []
end
def run(preloader)
preload(preloader)
end
def preload(preloader)
raise NotImplementedError
end
# The name of the key on the associated records
def association_key_name
raise NotImplementedError
end
# The name of the key on the model which declares the association
def owner_key_name
raise NotImplementedError
end
private
def options
reflection.options
end
def associated_records_by_owner(preloader)
records = load_records do |record|
owner = owners_by_key[convert_key(record[association_key_name])]
association = owner.association(reflection.name)
association.set_inverse_instance(record)
end
owners.each_with_object({}) do |owner, result|
result[owner] = records[convert_key(owner[owner_key_name])] || []
end
end
def owner_keys
unless defined?(@owner_keys)
@owner_keys = owners.map do |owner|
owner[owner_key_name]
end
@owner_keys.uniq!
@owner_keys.compact!
end
@owner_keys
end
def owners_by_key
unless defined?(@owners_by_key)
@owners_by_key = owners.each_with_object({}) do |owner, h|
h[convert_key(owner[owner_key_name])] = owner
end
end
@owners_by_key
end
def key_conversion_required?
@key_conversion_required ||= association_key_type != owner_key_type
end
def convert_key(key)
if key_conversion_required?
key.to_s
else
key
end
end
def association_key_type
@klass.type_for_attribute(association_key_name.to_s).type
end
def owner_key_type
@model.type_for_attribute(owner_key_name.to_s).type
end
def load_records(&block)
return {} if owner_keys.empty?
# Some databases impose a limit on the number of ids in a list (in Oracle it's 1000)
# Make several smaller queries if necessary or make one query if the adapter supports it
slices = owner_keys.each_slice(klass.connection.in_clause_length || owner_keys.size)
@preloaded_records = slices.flat_map do |slice|
records_for(slice, &block)
end
@preloaded_records.group_by do |record|
convert_key(record[association_key_name])
end
end
def records_for(ids, &block)
scope.where(association_key_name => ids).load(&block)
end
def scope
@scope ||= build_scope
end
def reflection_scope
@reflection_scope ||= reflection.scope_for(klass)
end
def build_scope
scope = klass.default_scoped
if reflection.type
scope.where!(reflection.type => model.base_class.sti_name)
end
scope.merge!(reflection_scope)
scope.merge!(preload_scope) if preload_scope
scope
end
end
end
end
end
|