module Mongoid::Criteria::Queryable::Mergeable
Contains behavior for merging existing selection with new selection.
Attributes
@attribute [rw] strategy The name of the current strategy.
Public Instance Methods
Instruct the next mergeable call to use intersection.
@example Use intersection on the next call.
mergeable.intersect.in(field: [ 1, 2, 3 ])
@return [ Mergeable
] The intersect flagged mergeable.
@since 1.0.0
# File lib/mongoid/criteria/queryable/mergeable.rb, line 22 def intersect use(:__intersect__) end
Instruct the next mergeable call to use override.
@example Use override on the next call.
mergeable.override.in(field: [ 1, 2, 3 ])
@return [ Mergeable
] The override flagged mergeable.
@since 1.0.0
# File lib/mongoid/criteria/queryable/mergeable.rb, line 34 def override use(:__override__) end
Clear the current strategy and negating flag, used after cloning.
@example Reset the strategies.
mergeable.reset_strategies!
@return [ Criteria
] self.
@since 1.0.0
# File lib/mongoid/criteria/queryable/mergeable.rb, line 58 def reset_strategies! self.strategy = nil self.negating = nil self end
Instruct the next mergeable call to use union.
@example Use union on the next call.
mergeable.union.in(field: [ 1, 2, 3 ])
@return [ Mergeable
] The union flagged mergeable.
@since 1.0.0
# File lib/mongoid/criteria/queryable/mergeable.rb, line 46 def union use(:__union__) end
Private Instance Methods
Adds the criterion to the existing selection.
@api private
@example Add the criterion.
mergeable.__add__({ name: 1 }, "$in")
@param [ Hash ] criterion The criteria. @param [ String ] operator The MongoDB operator.
@return [ Mergeable
] The new mergeable.
@since 1.0.0
# File lib/mongoid/criteria/queryable/mergeable.rb, line 79 def __add__(criterion, operator) with_strategy(:__add__, criterion, operator) end
Adds the criterion to the existing selection.
@api private
@example Add the criterion.
mergeable.__expanded__([ 1, 10 ], "$within", "$center")
@param [ Hash ] criterion The criteria. @param [ String ] outer The outer MongoDB operator. @param [ String ] inner The inner MongoDB operator.
@return [ Mergeable
] The new mergeable.
@since 1.0.0
# File lib/mongoid/criteria/queryable/mergeable.rb, line 97 def __expanded__(criterion, outer, inner) selection(criterion) do |selector, field, value| selector.store(field, { outer => { inner => value }}) end end
Adds the criterion to the existing selection.
@api private
@example Add the criterion.
mergeable.__intersect__([ 1, 2 ], "$in")
@param [ Hash ] criterion The criteria. @param [ String ] operator The MongoDB operator.
@return [ Mergeable
] The new mergeable.
@since 1.0.0
# File lib/mongoid/criteria/queryable/mergeable.rb, line 135 def __intersect__(criterion, operator) with_strategy(:__intersect__, criterion, operator) end
Perform a straight merge of the criterion into the selection and let the symbol overrides do all the work.
@api private
@example Straight merge the expanded criterion.
mergeable.__merge__(location: [ 1, 10 ])
@param [ Hash ] criterion The criteria.
@return [ Mergeable
] The cloned object.
@since 2.0.0
# File lib/mongoid/criteria/queryable/mergeable.rb, line 116 def __merge__(criterion) selection(criterion) do |selector, field, value| selector.merge!(field.__expr_part__(value)) end end
Adds $and/$or/$nor criteria to a copy of this selection.
Each of the criteria can be a Hash of key/value pairs or MongoDB operators (keys beginning with $), or a Selectable
object (which typically will be a Criteria
instance).
@api private
@example Add the criterion.
mergeable.__multi__([ 1, 2 ], "$in")
@param [ Array<Hash | Criteria> ] criteria Multiple key/value pair
matches or Criteria objects.
@param [ String ] operator The MongoDB operator.
@return [ Mergeable
] The new mergeable.
@since 1.0.0
# File lib/mongoid/criteria/queryable/mergeable.rb, line 157 def __multi__(criteria, operator) clone.tap do |query| sel = query.selector criteria.flatten.each do |expr| next unless expr result_criteria = sel[operator] || [] if expr.is_a?(Selectable) expr = expr.selector end normalized = _mongoid_expand_keys(expr) sel.store(operator, result_criteria.push(normalized)) end end end
Adds the criterion to the existing selection.
@api private
@example Add the criterion.
mergeable.__override__([ 1, 2 ], "$in")
@param [ Hash | Criteria
] criterion The criteria. @param [ String ] operator The MongoDB operator.
@return [ Mergeable
] The new mergeable.
@since 1.0.0
# File lib/mongoid/criteria/queryable/mergeable.rb, line 342 def __override__(criterion, operator) if criterion.is_a?(Selectable) criterion = criterion.selector end selection(criterion) do |selector, field, value| expression = prepare(field, operator, value) existing = selector[field] if existing.respond_to?(:merge!) selector.store(field, existing.merge!(expression)) else selector.store(field, expression) end end end
Adds the criterion to the existing selection.
@api private
@example Add the criterion.
mergeable.__union__([ 1, 2 ], "$in")
@param [ Hash ] criterion The criteria. @param [ String ] operator The MongoDB operator.
@return [ Mergeable
] The new mergeable.
@since 1.0.0
# File lib/mongoid/criteria/queryable/mergeable.rb, line 370 def __union__(criterion, operator) with_strategy(:__union__, criterion, operator) end
Combines criteria into a MongoDB selector.
Criteria
is an array of criterions which will be flattened.
Each criterion can be:
-
A hash
-
A
Criteria
instance -
nil, in which case it is ignored
@api private
# File lib/mongoid/criteria/queryable/mergeable.rb, line 182 def _mongoid_add_top_level_operation(operator, criteria) # Flatten the criteria. The idea is that predicates in MongoDB # are always hashes and are never arrays. This method additionally # allows Criteria instances as predicates. # The flattening is existing Mongoid behavior but we could possibly # get rid of it as applications can splat their predicates, or # flatten if needed. clone.tap do |query| sel = query.selector _mongoid_flatten_arrays(criteria).each do |criterion| if criterion.is_a?(Selectable) expr = _mongoid_expand_keys(criterion.selector) else expr = _mongoid_expand_keys(criterion) end if sel.empty? sel.store(operator, [expr]) elsif sel.keys == [operator] sel.store(operator, sel[operator] + [expr]) else operands = [sel.dup] + [expr] sel.clear sel.store(operator, operands) end end end end
Takes a criteria hash and expands Key
objects into hashes containing MQL corresponding to said key objects. Also converts the input to BSON::Document
to permit indifferent access.
The argument must be a hash containing key-value pairs of the following forms:
-
{field_name: value}
-
{‘field_name’ => value}
-
{key_instance: value}
-
{:$operator => operator_value_expression}
-
{‘$operator’ => operator_value_expression}
Ruby does not permit multiple symbol operators. For example, {:foo.gt => 1, :foo.gt => 2} is collapsed to {:foo.gt => 2} by the language. Therefore this method never has to deal with multiple identical operators.
Similarly, this method should never need to expand a literal value and an operator at the same time.
This method effectively converts symbol keys to string keys in the input expr
, such that the downstream code can assume that conditions always contain string keys.
@param [ Hash ] expr Criteria
including Key
instances.
@return [ BSON::Document
] The expanded criteria.
# File lib/mongoid/criteria/queryable/mergeable.rb, line 256 def _mongoid_expand_keys(expr) unless expr.is_a?(Hash) raise ArgumentError, 'Argument must be a Hash' end result = BSON::Document.new expr.each do |field, value| field.__expr_part__(value.__expand_complex__, negating?).each do |k, v| if existing = result[k] if existing.is_a?(Hash) # Existing value is an operator. # If new value is also an operator, ensure there are no # conflicts and add if v.is_a?(Hash) # The new value is also an operator. # If there are no conflicts, combine the hashes, otherwise # add new conditions to top level with $and. if (v.keys & existing.keys).empty? existing.update(v) else raise NotImplementedError, 'Ruby does not allow same symbol operator with different values' result['$and'] ||= [] result['$and'] << {k => v} end else # The new value is a simple value. # Transform the implicit equality to either $eq or $regexp # depending on the type of the argument. See # https://docs.mongodb.com/manual/reference/operator/query/eq/#std-label-eq-usage-examples # for the description of relevant server behavior. op = case v when Regexp, BSON::Regexp::Raw '$regex' else '$eq' end # If there isn't an $eq/$regex operator already in the # query, transform the new value into an operator # expression and add it to the existing hash. Otherwise # add the new condition with $and to the top level. if existing.key?(op) raise NotImplementedError, 'Ruby does not allow same symbol operator with different values' result['$and'] ||= [] result['$and'] << {k => v} else existing.update(op => v) end end else # Existing value is a simple value. # See the notes above about transformations to $eq/$regex. op = case existing when Regexp, BSON::Regexp::Raw '$regex' else '$eq' end if v.is_a?(Hash) && !v.key?(op) result[k] = {op => existing}.update(v) else raise NotImplementedError, 'Ruby does not allow same symbol operator with different values' result['$and'] ||= [] result['$and'] << {k => v} end end else result[k] = v end end end result end
Calling .flatten on an array which includes a Criteria
instance evaluates the criteria, which we do not want. Hence this method explicitly only expands Array objects and Array subclasses.
# File lib/mongoid/criteria/queryable/mergeable.rb, line 213 def _mongoid_flatten_arrays(array) out = [] pending = array.dup until pending.empty? item = pending.shift if item.nil? # skip elsif item.is_a?(Array) pending += item else out << item end end out end
Prepare the value for merging.
@api private
@example Prepare the value.
mergeable.prepare("field", "$gt", 10)
@param [ String ] field The name of the field. @param [ Object
] value The value.
@return [ Object
] The serialized value.
@since 1.0.0
# File lib/mongoid/criteria/queryable/mergeable.rb, line 428 def prepare(field, operator, value) unless operator =~ /exists|type|size/ value = value.__expand_complex__ field = field.to_s name = aliases[field] || field serializer = serializers[name] value = serializer ? serializer.evolve(value) : value end selection = { operator => value } negating? ? { "$not" => selection } : selection end
Use the named strategy for the next operation.
@api private
@example Use intersection.
mergeable.use(:__intersect__)
@param [ Symbol ] strategy The strategy to use.
@return [ Mergeable
] The existing mergeable.
@since 1.0.0
# File lib/mongoid/criteria/queryable/mergeable.rb, line 386 def use(strategy) tap do |mergeable| mergeable.strategy = strategy end end
Add criterion to the selection with the named strategy.
@api private
@example Add criterion with a strategy.
mergeable.with_strategy(:__union__, {field_name: [ 1, 2, 3 ]}, "$in")
@param [ Symbol ] strategy The name of the strategy method. @param [ Object
] criterion The criterion to add. @param [ String ] operator The MongoDB operator.
@return [ Mergeable
] The cloned query.
@since 1.0.0
# File lib/mongoid/criteria/queryable/mergeable.rb, line 406 def with_strategy(strategy, criterion, operator) selection(criterion) do |selector, field, value| selector.store( field, selector[field].send(strategy, prepare(field, operator, value)) ) end end