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require 'active_support/core_ext/hash/keys'
require "set"
module ActiveRecord
class Relation
class HashMerger # :nodoc:
attr_reader :relation, :hash
def initialize(relation, hash)
hash.assert_valid_keys(*Relation::VALUE_METHODS)
@relation = relation
@hash = hash
end
def merge
Merger.new(relation, other).merge
end
# Applying values to a relation has some side effects. E.g.
# interpolation might take place for where values. So we should
# build a relation to merge in rather than directly merging
# the values.
def other
other = Relation.new(relation.klass, relation.table)
hash.each { |k, v|
if k == :joins
if Hash === v
other.joins!(v)
else
other.joins!(*v)
end
else
other.send("#{k}!", v)
end
}
other
end
end
class Merger # :nodoc:
attr_reader :relation, :values, :other
def initialize(relation, other)
if other.default_scoped? && other.klass != relation.klass
other = other.with_default_scope
end
@relation = relation
@values = other.values
@other = other
end
NORMAL_VALUES = Relation::SINGLE_VALUE_METHODS +
Relation::MULTI_VALUE_METHODS -
[:joins, :where, :order, :bind, :reverse_order, :lock, :create_with, :reordering, :from] # :nodoc:
def normal_values
NORMAL_VALUES
end
def merge
normal_values.each do |name|
value = values[name]
relation.send("#{name}!", *value) unless value.blank?
end
merge_multi_values
merge_single_values
merge_joins
relation
end
private
def merge_joins
return if values[:joins].blank?
if other.klass == relation.klass
relation.joins! *values[:joins]
else
joins_dependency, rest = values[:joins].partition do |join|
case join
when Hash, Symbol, Array
true
else
false
end
end
join_dependency = ActiveRecord::Associations::JoinDependency.new(other.klass,
joins_dependency,
[])
relation.joins! rest
join_dependency.join_associations.each do |association|
@relation = association.join_relation(relation)
end
end
end
def merge_multi_values
relation.where_values = merged_wheres
relation.bind_values = merged_binds
if values[:reordering]
# override any order specified in the original relation
relation.reorder! values[:order]
elsif values[:order]
# merge in order_values from r
relation.order! values[:order]
end
relation.extend(*values[:extending]) unless values[:extending].blank?
end
def merge_single_values
relation.from_value = values[:from] unless relation.from_value
relation.lock_value = values[:lock] unless relation.lock_value
relation.reverse_order_value = values[:reverse_order]
unless values[:create_with].blank?
relation.create_with_value = (relation.create_with_value || {}).merge(values[:create_with])
end
end
def merged_binds
if values[:bind]
(relation.bind_values + values[:bind]).uniq(&:first)
else
relation.bind_values
end
end
def merged_wheres
values[:where] ||= []
if values[:where].empty? || relation.where_values.empty?
relation.where_values + values[:where]
else
# Remove equalities from the existing relation with a LHS which is
# present in the relation being merged in.
seen = Set.new
values[:where].each { |w|
if w.respond_to?(:operator) && w.operator == :==
seen << w.left
end
}
relation.where_values.reject { |w|
w.respond_to?(:operator) &&
w.operator == :== &&
seen.include?(w.left)
} + values[:where]
end
end
end
end
end
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