/
predicate_builder.rb
155 lines (132 loc) · 4.69 KB
/
predicate_builder.rb
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module ActiveRecord
class PredicateBuilder # :nodoc:
@handlers = []
autoload :RelationHandler, 'active_record/relation/predicate_builder/relation_handler'
autoload :ArrayHandler, 'active_record/relation/predicate_builder/array_handler'
def self.resolve_column_aliases(klass, hash)
# This method is a hot spot, so for now, use Hash[] to dup the hash.
# https://bugs.ruby-lang.org/issues/7166
hash = Hash[hash]
hash.keys.grep(Symbol) do |key|
if klass.attribute_alias? key
hash[klass.attribute_alias(key)] = hash.delete key
end
end
hash
end
def self.build_from_hash(klass, attributes, default_table)
queries = []
attributes.each do |column, value|
table = default_table
if value.is_a?(Hash)
if value.empty?
queries << '1=0'
else
table = Arel::Table.new(column, default_table.engine)
association = klass._reflect_on_association(column)
value.each do |k, v|
queries.concat expand(association && association.klass, table, k, v)
end
end
else
column = column.to_s
if column.include?('.')
table_name, column = column.split('.', 2)
table = Arel::Table.new(table_name, default_table.engine)
end
queries.concat expand(klass, table, column, value)
end
end
queries
end
def self.expand(klass, table, column, value)
queries = []
# Find the foreign key when using queries such as:
# Post.where(author: author)
#
# For polymorphic relationships, find the foreign key and type:
# PriceEstimate.where(estimate_of: treasure)
if klass && reflection = klass._reflect_on_association(column)
base_class = polymorphic_base_class_from_value(value)
if reflection.polymorphic? && base_class
queries << build(table[reflection.foreign_type], base_class)
end
column = reflection.foreign_key
if base_class
primary_key = reflection.association_primary_key(base_class)
value = convert_value_to_association_ids(value, primary_key)
end
end
queries << build(table[column], value)
queries
end
def self.polymorphic_base_class_from_value(value)
case value
when Relation
value.klass.base_class
when Array
val = value.compact.first
val.class.base_class if val.is_a?(Base)
when Base
value.class.base_class
end
end
def self.references(attributes)
attributes.map do |key, value|
if value.is_a?(Hash)
key
else
key = key.to_s
key.split('.').first if key.include?('.')
end
end.compact
end
# Define how a class is converted to Arel nodes when passed to +where+.
# The handler can be any object that responds to +call+, and will be used
# for any value that +===+ the class given. For example:
#
# MyCustomDateRange = Struct.new(:start, :end)
# handler = proc do |column, range|
# Arel::Nodes::Between.new(column,
# Arel::Nodes::And.new([range.start, range.end])
# )
# end
# ActiveRecord::PredicateBuilder.register_handler(MyCustomDateRange, handler)
def self.register_handler(klass, handler)
@handlers.unshift([klass, handler])
end
BASIC_OBJECT_HANDLER = ->(attribute, value) { attribute.eq(value) } # :nodoc:
register_handler(BasicObject, BASIC_OBJECT_HANDLER)
# FIXME: I think we need to deprecate this behavior
register_handler(Class, ->(attribute, value) { attribute.eq(value.name) })
register_handler(Base, ->(attribute, value) { attribute.eq(value.id) })
register_handler(Range, ->(attribute, value) { attribute.between(value) })
register_handler(Relation, RelationHandler.new)
register_handler(Array, ArrayHandler.new)
def self.build(attribute, value)
handler_for(value).call(attribute, value)
end
private_class_method :build
def self.handler_for(object)
@handlers.detect { |klass, _| klass === object }.last
end
private_class_method :handler_for
def self.convert_value_to_association_ids(value, primary_key)
case value
when Relation
value.select(primary_key)
when Array
value.map { |v| convert_value_to_association_ids(v, primary_key) }
when Base
value._read_attribute(primary_key)
else
value
end
end
def self.can_be_bound?(value) # :nodoc:
!value.nil? &&
!value.is_a?(Hash) &&
handler_for(value) == BASIC_OBJECT_HANDLER
end
end
end