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.create(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) @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 @relation = join_dependency.join_relation(relation) end end def merge_multi_values lhs_wheres = relation.where_values rhs_wheres = values[:where] || [] lhs_binds = relation.bind_values rhs_binds = values[:bind] || [] removed, kept = partition_overwrites(lhs_wheres, rhs_wheres) where_values = kept + rhs_wheres bind_values = filter_binds(lhs_binds, removed) + rhs_binds conn = relation.klass.connection bviter = bind_values.each.with_index where_values.map! do |node| if Arel::Nodes::Equality === node && Arel::Nodes::BindParam === node.right (column, _), i = bviter.next substitute = conn.substitute_at column, i Arel::Nodes::Equality.new(node.left, substitute) else node end end relation.where_values = where_values relation.bind_values = bind_values if values[:reordering] # override any order specified in the original relation relation.reorder! values[:order] elsif values[:order] # merge in order_values from relation 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 filter_binds(lhs_binds, removed_wheres) return lhs_binds if removed_wheres.empty? set = Set.new removed_wheres.map { |x| x.left.name } 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