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Diffstat (limited to 'activerecord/lib/active_record/relation/merger.rb')
-rw-r--r-- | activerecord/lib/active_record/relation/merger.rb | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/relation/merger.rb b/activerecord/lib/active_record/relation/merger.rb new file mode 100644 index 0000000000..36f98c6480 --- /dev/null +++ b/activerecord/lib/active_record/relation/merger.rb @@ -0,0 +1,122 @@ +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 |