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 #: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) 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::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] # 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_joins relation end private 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 lhs_wheres = relation.where_values rhs_wheres = other.where_values lhs_binds = relation.bind_values rhs_binds = other.bind_values removed, kept = partition_overwrites(lhs_wheres, rhs_wheres) where_values = kept + rhs_wheres bind_values = filter_binds(lhs_binds, removed) + rhs_binds relation.where_values = where_values relation.bind_values = bind_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 relation.from_value = other.from_value unless relation.from_value relation.lock_value = other.lock_value unless relation.lock_value unless other.create_with_value.blank? relation.create_with_value = (relation.create_with_value || {}).merge(other.create_with_value) end end def filter_binds(lhs_binds, removed_wheres) return lhs_binds if removed_wheres.empty? set = Set.new removed_wheres.map { |x| x.left.name.to_s } lhs_binds.dup.delete_if { |col,_| set.include? col.name } end # Remove equalities from the existing relation with a LHS which is # present in the relation being merged in. # returns [things_to_remove, things_to_keep] def partition_overwrites(lhs_wheres, rhs_wheres) if lhs_wheres.empty? || rhs_wheres.empty? return [[], lhs_wheres] end nodes = rhs_wheres.find_all do |w| w.respond_to?(:operator) && w.operator == :== end seen = Set.new(nodes) { |node| node.left } lhs_wheres.partition do |w| w.respond_to?(:operator) && w.operator == :== && seen.include?(w.left) end end end end end