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require 'active_support/core_ext/object/blank'
require 'active_support/core_ext/hash/keys'
module ActiveRecord
class Relation
class HashMerger
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| other.send("#{k}!", v) }
other
end
end
class Merger
attr_reader :relation, :values
def initialize(relation, other)
if other.default_scoped? && other.klass != relation.klass
other = other.with_default_scope
end
@relation = relation
@values = other.values
end
def normal_values
Relation::SINGLE_VALUE_METHODS +
Relation::MULTI_VALUE_METHODS -
[:where, :order, :bind, :reverse_order, :lock, :create_with, :reordering, :from]
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
relation
end
private
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
if values[:where]
merged_wheres = relation.where_values + values[:where]
unless relation.where_values.empty?
# Remove duplicates, last one wins.
seen = Hash.new { |h,table| h[table] = {} }
merged_wheres = merged_wheres.reverse.reject { |w|
nuke = false
if w.respond_to?(:operator) && w.operator == :==
name = w.left.name
table = w.left.relation.name
nuke = seen[table][name]
seen[table][name] = true
end
nuke
}.reverse
end
merged_wheres
else
relation.where_values
end
end
end
end
end
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