require 'active_support/core_ext/object/blank'
module ActiveRecord
module SpawnMethods
def merge(r)
return self unless r
return to_a & r if r.is_a?(Array)
merged_relation = clone
r = r.with_default_scope if r.default_scoped? && r.klass != klass
Relation::ASSOCIATION_METHODS.each do |method|
value = r.send(:"#{method}_values")
unless value.empty?
if method == :includes
merged_relation = merged_relation.includes(value)
else
merge_relation_method(merged_relation, method, value)
end
end
end
(Relation::MULTI_VALUE_METHODS - [:joins, :where, :order]).each do |method|
value = r.send(:"#{method}_values")
merge_relation_method(merged_relation, method, value) if value.present?
end
merge_joins(merged_relation, r)
merged_wheres = @where_values + r.where_values
unless @where_values.empty?
# Remove duplicate ARel attributes. 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 == :== &&
w.left.respond_to?(:relation)
name = w.left.name
table = w.left.relation.name
nuke = seen[table][name]
seen[table][name] = true
end
nuke
}.reverse
end
merged_relation.where_values = merged_wheres
(Relation::SINGLE_VALUE_METHODS - [:lock, :create_with, :reordering]).each do |method|
value = r.send(:"#{method}_value")
merged_relation.send(:"#{method}_value=", value) unless value.nil?
end
merged_relation.lock_value = r.lock_value unless merged_relation.lock_value
merged_relation = merged_relation.create_with(r.create_with_value) unless r.create_with_value.empty?
if (r.reordering_value)
# override any order specified in the original relation
merged_relation.reordering_value = true
merged_relation.order_values = r.order_values
else
# merge in order_values from r
merged_relation.order_values += r.order_values
end
# Apply scope extension modules
merged_relation.send :apply_modules, r.extensions
merged_relation
end
# Removes from the query the condition(s) specified in +skips+.
#
# Example:
#
# Post.order('id asc').except(:order) # discards the order condition
# Post.where('id > 10').order('id asc').except(:where) # discards the where condition but keeps the order
#
def except(*skips)
result = self.class.new(@klass, table)
result.default_scoped = default_scoped
((Relation::ASSOCIATION_METHODS + Relation::MULTI_VALUE_METHODS) - skips).each do |method|
result.send(:"#{method}_values=", send(:"#{method}_values"))
end
(Relation::SINGLE_VALUE_METHODS - skips).each do |method|
result.send(:"#{method}_value=", send(:"#{method}_value"))
end
# Apply scope extension modules
result.send(:apply_modules, extensions)
result
end
# Removes any condition from the query other than the one(s) specified in +onlies+.
#
# Example:
#
# Post.order('id asc').only(:where) # discards the order condition
# Post.order('id asc').only(:where, :order) # uses the specified order
#
def only(*onlies)
result = self.class.new(@klass, table)
result.default_scoped = default_scoped
((Relation::ASSOCIATION_METHODS + Relation::MULTI_VALUE_METHODS) & onlies).each do |method|
result.send(:"#{method}_values=", send(:"#{method}_values"))
end
(Relation::SINGLE_VALUE_METHODS & onlies).each do |method|
result.send(:"#{method}_value=", send(:"#{method}_value"))
end
# Apply scope extension modules
result.send(:apply_modules, extensions)
result
end
VALID_FIND_OPTIONS = [ :conditions, :include, :joins, :limit, :offset, :extend,
:order, :select, :readonly, :group, :having, :from, :lock ]
def apply_finder_options(options)
relation = clone
return relation unless options
options.assert_valid_keys(VALID_FIND_OPTIONS)
finders = options.dup
finders.delete_if { |key, value| value.nil? && key != :limit }
([:joins, :select, :group, :order, :having, :limit, :offset, :from, :lock, :readonly] & finders.keys).each do |finder|
relation = relation.send(finder, finders[finder])
end
relation = relation.where(finders[:conditions]) if options.has_key?(:conditions)
relation = relation.includes(finders[:include]) if options.has_key?(:include)
relation = relation.extending(finders[:extend]) if options.has_key?(:extend)
relation
end
private
def merge_joins(relation, other)
values = other.joins_values
return if values.blank?
if other.klass >= relation.klass
relation.joins_values += values
else
joins_dependency, rest = 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_values += join_dependency.join_associations + rest
end
end
def merge_relation_method(relation, method, value)
relation.send(:"#{method}_values=", relation.send(:"#{method}_values") + value)
end
end
end