diff options
Diffstat (limited to 'activerecord/lib/active_record/relation/merger.rb')
| -rw-r--r-- | activerecord/lib/active_record/relation/merger.rb | 133 |
1 files changed, 86 insertions, 47 deletions
diff --git a/activerecord/lib/active_record/relation/merger.rb b/activerecord/lib/active_record/relation/merger.rb index 59226d316e..a27f990f74 100644 --- a/activerecord/lib/active_record/relation/merger.rb +++ b/activerecord/lib/active_record/relation/merger.rb @@ -1,4 +1,5 @@ require 'active_support/core_ext/hash/keys' +require "set" module ActiveRecord class Relation @@ -12,7 +13,7 @@ module ActiveRecord @hash = hash end - def merge + def merge #:nodoc: Merger.new(relation, other).merge end @@ -21,7 +22,7 @@ module ActiveRecord # build a relation to merge in rather than directly merging # the values. def other - other = Relation.new(relation.klass, relation.table) + other = Relation.create(relation.klass, relation.table) hash.each { |k, v| if k == :joins if Hash === v @@ -29,6 +30,8 @@ module ActiveRecord else other.joins!(*v) end + elsif k == :select + other._select!(v) else other.send("#{k}!", v) end @@ -38,20 +41,17 @@ module ActiveRecord end class Merger # :nodoc: - attr_reader :relation, :values + 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 - - [:where, :order, :bind, :reverse_order, :lock, :create_with, :reordering, :from] # :nodoc: + [:joins, :where, :order, :bind, :reverse_order, :lock, :create_with, :reordering, :from] # :nodoc: def normal_values NORMAL_VALUES @@ -60,70 +60,109 @@ module ActiveRecord def merge normal_values.each do |name| value = values[name] - relation.send("#{name}!", *value) unless value.blank? + # 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 - relation.where_values = merged_wheres - relation.bind_values = merged_binds + 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) - if values[:reordering] + 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! values[:order] - elsif values[:order] - # merge in order_values from r - relation.order! values[:order] + relation.reorder! other.order_values + elsif other.order_values + # merge in order_values from relation + relation.order! other.order_values end - relation.extend(*values[:extending]) unless values[:extending].blank? + relation.extend(*other.extending_values) unless other.extending_values.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] + relation.from_value = other.from_value unless relation.from_value + relation.lock_value = other.lock_value unless relation.lock_value - unless values[:create_with].blank? - relation.create_with_value = (relation.create_with_value || {}).merge(values[:create_with]) + unless other.create_with_value.blank? + relation.create_with_value = (relation.create_with_value || {}).merge(other.create_with_value) end end - def merged_binds - if values[:bind] - (relation.bind_values + values[:bind]).uniq(&:first) - else - relation.bind_values - 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 - def merged_wheres - if values[:where] - merged_wheres = relation.where_values + values[:where] - - unless relation.where_values.empty? - # Remove equalities with duplicated left-hand. Last one wins. - seen = {} - merged_wheres = merged_wheres.reverse.reject { |w| - nuke = false - if w.respond_to?(:operator) && w.operator == :== - nuke = seen[w.left] - seen[w.left] = true - end - nuke - }.reverse - 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 - merged_wheres - else - relation.where_values + 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 |