This module is responsible for taking update selectors and switching out the indexes for the $ positional operator where appropriate.
@since 3.1.0
Takes the provided selector and atomic operations and replaces the indexes of the embedded documents with the positional operator when needed.
@note The only time we can accurately know when to use the positional
operator is at the exact time we are going to persist something. So we can tell by the selector that we are sending if it is actually possible to use the positional operator at all. For example, if the selector is: { "_id" => 1 }, then we could not use the positional operator for updating embedded documents since there would never be a match - we base whether we can based on the number of levels deep the selector goes, and if the id values are not nil.
@example Process the operations.
positionally( { "_id" => 1, "addresses._id" => 2 }, { "$set" => { "addresses.0.street" => "hobrecht" }} )
@param [ Hash ] selector The selector. @param [ Hash ] operations The update operations. @param [ Hash ] processed The processed update operations.
@return [ Hash ] The new operations.
@since 3.1.0
# File lib/mongoid/atomic/positionable.rb, line 36 def positionally(selector, operations, processed = {}) if selector.size == 1 || selector.values.any? { |val| val.nil? } return operations end keys = selector.keys.map{ |m| m.sub('._id','') } - ['_id'] keys = keys.sort_by { |s| s.length*-1 } process_operations(keys, operations, processed) end
# File lib/mongoid/atomic/positionable.rb, line 47 def process_operations(keys, operations, processed) operations.each_pair do |operation, update| processed[operation] = process_updates(keys, update) end processed end
# File lib/mongoid/atomic/positionable.rb, line 54 def process_updates(keys, update, updates = {}) update.each_pair do |position, value| updates[replace_index(keys, position)] = value end updates end
# File lib/mongoid/atomic/positionable.rb, line 61 def replace_index(keys, position) # replace to $ only if that key is on the selector keys.each do |kk| if position =~ /^#{kk}\.\d+\.(.*)/ return "#{kk}.$.#{$1}" end end position end