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require "active_support/core_ext/hash/keys"
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 #:nodoc:
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.create(relation.klass, relation.table, relation.predicate_builder)
hash.each { |k, v|
if k == :joins
if Hash === v
other.joins!(v)
else
other.joins!(*v)
end
elsif k == :select
other._select!(v)
else
other.send("#{k}!", v)
end
}
other
end
end
class Merger # :nodoc:
attr_reader :relation, :values, :other
def initialize(relation, other)
@relation = relation
@values = other.values
@other = other
end
NORMAL_VALUES = Relation::VALUE_METHODS -
Relation::CLAUSE_METHODS -
[:includes, :preload, :joins, :order, :reverse_order, :lock, :create_with, :reordering] # :nodoc:
def normal_values
NORMAL_VALUES
end
def merge
normal_values.each do |name|
value = values[name]
# The unless clause is here mostly for performance reasons (since the `send` call might be moderately
# expensive), most of the time the value is going to be `nil` or `.blank?`, the only catch is that
# `false.blank?` returns `true`, so there needs to be an extra check so that explicit `false` values
# don't fall through the cracks.
unless value.nil? || (value.blank? && false != value)
if name == :select
relation._select!(*value)
else
relation.send("#{name}!", *value)
end
end
end
merge_multi_values
merge_single_values
merge_clauses
merge_preloads
merge_joins
relation
end
private
def merge_preloads
return if other.preload_values.empty? && other.includes_values.empty?
if other.klass == relation.klass
relation.preload!(*other.preload_values) unless other.preload_values.empty?
relation.includes!(other.includes_values) unless other.includes_values.empty?
else
reflection = relation.klass.reflect_on_all_associations.find do |r|
r.class_name == other.klass.name
end || return
unless other.preload_values.empty?
relation.preload! reflection.name => other.preload_values
end
unless other.includes_values.empty?
relation.includes! reflection.name => other.includes_values
end
end
end
def merge_joins
return if other.joins_values.blank?
if other.klass == relation.klass
relation.joins!(*other.joins_values)
else
joins_dependency, rest = other.joins_values.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
@relation = relation.joins join_dependency
end
end
def merge_multi_values
if other.reordering_value
# override any order specified in the original relation
relation.reorder! other.order_values
elsif other.order_values
# merge in order_values from relation
relation.order! other.order_values
end
relation.extend(*other.extending_values) unless other.extending_values.blank?
end
def merge_single_values
if relation.from_clause.empty?
relation.from_clause = other.from_clause
end
relation.lock_value ||= other.lock_value
unless other.create_with_value.blank?
relation.create_with_value = (relation.create_with_value || {}).merge(other.create_with_value)
end
end
def merge_clauses
CLAUSE_METHODS.each do |method|
clause = relation.get_value(method)
other_clause = other.get_value(method)
relation.set_value(method, clause.merge(other_clause))
end
end
end
end
end
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