lib/bson/array.rb
# frozen_string_literal: true
# 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.
# The top-level BSON module.
module BSON
# Injects behaviour for encoding and decoding arrays to
# and from raw bytes as specified by the BSON spec.
#
# @see http://bsonspec.org/#/specification
#
# @since 2.0.0
module Array
# An array is type 0x04 in the BSON spec.
#
# @since 2.0.0
BSON_TYPE = ::String.new(4.chr, encoding: BINARY).freeze
# Get the array as encoded BSON.
#
# @example Get the array as encoded BSON.
# [ 1, 2, 3 ].to_bson
#
# @note Arrays are encoded as documents, where the index of the value in
# the array is the actual key.
#
# @return [ BSON::ByteBuffer ] The buffer with the encoded object.
#
# @see http://bsonspec.org/#/specification
#
# @since 2.0.0
def to_bson(buffer = ByteBuffer.new)
if buffer.respond_to?(:put_array)
buffer.put_array(self)
else
position = buffer.length
buffer.put_int32(0)
each_with_index do |value, index|
unless value.respond_to?(:bson_type)
raise Error::UnserializableClass,
"Array element at position #{index} does not define its BSON serialized type: #{value}"
end
buffer.put_byte(value.bson_type)
buffer.put_cstring(index.to_s)
value.to_bson(buffer)
end
buffer.put_byte(NULL_BYTE)
buffer.replace_int32(position, buffer.length - position)
end
end
# Convert the array to an object id. This will only work for arrays of size
# 12 where the elements are all strings.
#
# @example Convert the array to an object id.
# array.to_bson_object_id
#
# @note This is used for repairing legacy bson data.
#
# @raise [ BSON::Error::InvalidObjectId ] If the array is not 12 elements.
#
# @return [ String ] The raw object id bytes.
#
# @since 2.0.0
def to_bson_object_id
ObjectId.repair(self) { pack('C*') }
end
# Converts the array to a normalized value in a BSON document.
#
# @example Convert the array to a normalized value.
# array.to_bson_normalized_value
#
# @return [ Array ] The normalized array.
#
# @since 3.0.0
def to_bson_normalized_value
map(&:to_bson_normalized_value)
end
# Converts this object to a representation directly serializable to
# Extended JSON (https://github.com/mongodb/specifications/blob/master/source/extended-json.rst).
#
# This method recursively invokes +as_extended_json+ with the provided
# options on each array element.
#
# @option opts [ nil | :relaxed | :legacy ] :mode Serialization mode
# (default is canonical extended JSON)
#
# @return [ Array ] This array converted to extended json representation.
def as_extended_json(**options)
map do |item|
item.as_extended_json(**options)
end
end
# Class-level methods to be added to the Array class.
module ClassMethods
# Deserialize the array from BSON.
#
# @note If the argument cannot be parsed, an exception will be raised
# and the argument will be left in an undefined state. The caller
# must explicitly call `rewind` on the buffer before trying to parse
# it again.
#
# @param [ ByteBuffer ] buffer The byte buffer.
#
# @option options [ nil | :bson ] :mode Decoding mode to use.
#
# @return [ Array ] The decoded array.
#
# @see http://bsonspec.org/#/specification
def from_bson(buffer, **options)
if buffer.respond_to?(:get_array)
buffer.get_array(**options)
else
parse_array_from_buffer(buffer, **options)
end
end
private
# Parse an array from the buffer.
#
# @param [ ByteBuf ] buffer the buffer to read from
# @param [ Hash ] options the optional keyword arguments
#
# @return [ Array ] the array that was parsed
#
# @raise [ BSON::Error::BSONDecodeError ] if the expected number of
# bytes were not read from the buffer
def parse_array_from_buffer(buffer, **options)
new.tap do |array|
start_position = buffer.read_position
expected_byte_size = buffer.get_int32
parse_array_elements_from_buffer(array, buffer, **options)
actual_byte_size = buffer.read_position - start_position
if actual_byte_size != expected_byte_size
raise Error::BSONDecodeError,
"Expected array to take #{expected_byte_size} bytes but it took #{actual_byte_size} bytes"
end
end
end
# Parse a sequence of array elements from the buffer.
#
# @param [ Array ] array the array to populate
# @param [ ByteBuf ] buffer the buffer to read from
# @param [ Hash ] options the optional keyword arguments
def parse_array_elements_from_buffer(array, buffer, **options)
while (type = buffer.get_byte) != NULL_BYTE
buffer.get_cstring
cls = BSON::Registry.get(type)
value = if options.empty?
cls.from_bson(buffer)
else
cls.from_bson(buffer, **options)
end
array << value
end
end
end
# Register this type when the module is loaded.
Registry.register(BSON_TYPE, ::Array)
end
# Enrich the core Array class with this module.
::Array.include Array
::Array.extend Array::ClassMethods
end