lib/bson/code_with_scope.rb
# frozen_string_literal: true
# rubocop:todo all
# Copyright (C) 2009-2020 MongoDB Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
module BSON
# Represents a code with scope, which is a wrapper around javascript code
# with variable scope provided.
#
# @see http://bsonspec.org/#/specification
#
# @since 2.0.0
class CodeWithScope
include JSON
# A code with scope is type 0x0F in the BSON spec.
#
# @since 2.0.0
BSON_TYPE = ::String.new(15.chr, encoding: BINARY).freeze
# @!attribute javascript
# @return [ String ] The javascript code.
# @since 2.0.0
# @!attribute scope
# @return [ Hash ] The variable scope.
# @since 2.0.0
attr_reader :javascript, :scope
# Determine if this code with scope object is equal to another object.
#
# @example Check the code with scope equality.
# code_with_scope == other
#
# @param [ Object ] other The object to compare against.
#
# @return [ true, false ] If the objects are equal.
#
# @since 2.0.0
def ==(other)
return false unless other.is_a?(CodeWithScope)
javascript == other.javascript && scope == other.scope
end
# Return a representation of the object for use in
# application-level JSON serialization. Since BSON::CodeWithScope
# is used exclusively in BSON-related contexts, this
# method returns the canonical Extended JSON representation.
#
# @return [ Hash ] The extended json representation.
def as_json(*_args)
as_extended_json
end
# Converts this object to a representation directly serializable to
# Extended JSON (https://github.com/mongodb/specifications/blob/master/source/extended-json.rst).
#
# @option opts [ nil | :relaxed | :legacy ] :mode Serialization mode
# (default is canonical extended JSON)
#
# @return [ Hash ] The extended json representation.
def as_extended_json(**options)
{ "$code" => javascript, "$scope" => scope.as_extended_json(**options) }
end
# Instantiate the new code with scope.
#
# @example Instantiate the code with scope.
# BSON::CodeWithScope.new("this.value = name", name: "sid")
#
# @param [ String ] javascript The javascript code.
# @param [ Hash ] scope The variable scope.
#
# @since 2.0.0
def initialize(javascript = "", scope = {})
@javascript = javascript
@scope = scope
end
# Encode the javascript code with scope.
#
# @example Encode the code with scope.
# code_with_scope.to_bson
#
# @return [ BSON::ByteBuffer ] The buffer with the encoded object.
#
# @see http://bsonspec.org/#/specification
#
# @since 2.0.0
def to_bson(buffer = ByteBuffer.new)
position = buffer.length
buffer.put_int32(0)
buffer.put_string(javascript)
scope.to_bson(buffer)
buffer.replace_int32(position, buffer.length - position)
end
# Deserialize a code with scope from BSON.
#
# @param [ ByteBuffer ] buffer The byte buffer.
#
# @option options [ nil | :bson ] :mode Decoding mode to use.
#
# @return [ TrueClass, FalseClass ] The decoded code with scope.
#
# @see http://bsonspec.org/#/specification
#
# @since 2.0.0
def self.from_bson(buffer, **options)
# Code with scope has a length (?) field which is not needed for
# decoding, but spec tests want this field validated.
start_position = buffer.read_position
length = buffer.get_int32
javascript = buffer.get_string
scope = if options.empty?
::Hash.from_bson(buffer)
else
::Hash.from_bson(buffer, **options)
end
read_bytes = buffer.read_position - start_position
if read_bytes != length
raise Error::BSONDecodeError, "CodeWithScope invalid: claimed length #{length}, actual length #{read_bytes}"
end
new(javascript, scope)
end
# Register this type when the module is loaded.
#
# @since 2.0.0
Registry.register(BSON_TYPE, self)
end
end