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
|
module ActiveRecord
module Associations
class JoinDependency # :nodoc:
autoload :JoinBase, 'active_record/associations/join_dependency/join_base'
autoload :JoinAssociation, 'active_record/associations/join_dependency/join_association'
attr_reader :alias_tracker, :base_klass, :join_root
def self.make_tree(associations)
hash = {}
walk_tree associations, hash
hash
end
def self.walk_tree(associations, hash)
case associations
when Symbol, String
hash[associations.to_sym] ||= {}
when Array
associations.each do |assoc|
walk_tree assoc, hash
end
when Hash
associations.each do |k,v|
cache = hash[k] ||= {}
walk_tree v, cache
end
else
raise ConfigurationError, associations.inspect
end
end
# base is the base class on which operation is taking place.
# associations is the list of associations which are joined using hash, symbol or array.
# joins is the list of all string join commnads and arel nodes.
#
# Example :
#
# class Physician < ActiveRecord::Base
# has_many :appointments
# has_many :patients, through: :appointments
# end
#
# If I execute `@physician.patients.to_a` then
# base #=> Physician
# associations #=> []
# joins #=> [#<Arel::Nodes::InnerJoin: ...]
#
# However if I execute `Physician.joins(:appointments).to_a` then
# base #=> Physician
# associations #=> [:appointments]
# joins #=> []
#
def initialize(base, associations, joins)
@base_klass = base
@table_joins = joins
@join_root = JoinBase.new(base)
@alias_tracker = AliasTracker.new(base.connection, joins)
@alias_tracker.aliased_name_for(base.table_name) # Updates the count for base.table_name to 1
tree = self.class.make_tree associations
build tree, @join_root, Arel::InnerJoin
end
def reflections
join_root.drop(1).map!(&:reflection)
end
def merge_outer_joins!(other)
left = join_root
right = other.join_root
if left.match? right
merge_node left, right
else
# If the roots aren't the same, then deep copy the RHS to the LHS
left.children.concat right.children.map { |node|
deep_copy left, node
}
end
end
def join_constraints
join_root.flat_map(&:join_constraints)
end
def columns
join_root.collect { |join_part|
table = join_part.aliased_table
join_part.column_names_with_alias.collect{ |column_name, aliased_name|
table[column_name].as Arel.sql(aliased_name)
}
}.flatten
end
def instantiate(result_set)
primary_key = join_root.aliased_primary_key
parents = {}
type_caster = result_set.column_type primary_key
assoc = join_root.children
records = result_set.map { |row_hash|
primary_id = type_caster.type_cast row_hash[primary_key]
parent = parents[primary_id] ||= join_root.instantiate(row_hash)
construct(parent, assoc, row_hash, result_set)
parent
}.uniq
remove_duplicate_results!(base_klass, records, assoc)
records
end
private
def merge_node(left, right)
intersection, missing = right.children.map { |node1|
[left.children.find { |node2| node1.match? node2 }, node1]
}.partition(&:first)
intersection.each { |l,r| merge_node l, r }
left.children.concat missing.map { |_,node| deep_copy left, node }
end
def deep_copy(parent, node)
dup = build_join_association(node.reflection, parent, Arel::OuterJoin)
dup.children.concat node.children.map { |n| deep_copy dup, n }
dup
end
def remove_duplicate_results!(base, records, associations)
associations.each do |node|
reflection = base.reflect_on_association(node.name)
remove_uniq_by_reflection(reflection, records)
parent_records = []
records.each do |record|
if descendant = record.send(reflection.name)
if reflection.collection?
parent_records.concat descendant.target.uniq
else
parent_records << descendant
end
end
end
unless parent_records.empty?
remove_duplicate_results!(reflection.klass, parent_records, node.children)
end
end
end
def find_reflection(klass, name)
klass.reflect_on_association(name) or
raise ConfigurationError, "Association named '#{ name }' was not found on #{ klass.name }; perhaps you misspelled it?"
end
def build(associations, parent, join_type)
associations.each do |name, right|
reflection = find_reflection parent.base_klass, name
join_association = build_join_association reflection, parent, join_type
parent.children << join_association
build right, join_association, join_type
end
end
def build_scalar(reflection, parent, join_type)
join_association = build_join_association(reflection, parent, join_type)
parent.children << join_association
end
def remove_uniq_by_reflection(reflection, records)
if reflection && reflection.collection?
records.each { |record| record.send(reflection.name).target.uniq! }
end
end
def build_join_association(reflection, parent, join_type)
reflection.check_validity!
if reflection.options[:polymorphic]
raise EagerLoadPolymorphicError.new(reflection)
end
JoinAssociation.new(reflection, join_root.to_a.length, parent, join_type, alias_tracker)
end
def construct(parent, nodes, row, rs)
nodes.each do |node|
association = construct_association(parent, node, row, rs)
construct(association, node.children, row, rs) if association
end
end
def construct_association(record, join_part, row, rs)
caster = rs.column_type(join_part.parent.aliased_primary_key)
row_id = caster.type_cast row[join_part.parent.aliased_primary_key]
return if record.id != row_id
macro = join_part.reflection.macro
if macro == :has_one
return record.association(join_part.reflection.name).target if record.association_cache.key?(join_part.reflection.name)
association = join_part.instantiate(row) unless row[join_part.aliased_primary_key].nil?
set_target_and_inverse(join_part, association, record)
else
association = join_part.instantiate(row) unless row[join_part.aliased_primary_key].nil?
case macro
when :has_many
other = record.association(join_part.reflection.name)
other.loaded!
other.target.push(association) if association
other.set_inverse_instance(association)
when :belongs_to
set_target_and_inverse(join_part, association, record)
else
raise ConfigurationError, "unknown macro: #{join_part.reflection.macro}"
end
end
association
end
def set_target_and_inverse(join_part, association, record)
other = record.association(join_part.reflection.name)
other.target = association
other.set_inverse_instance(association)
end
end
end
end
|