lib/mongo/operation/aggregate/result.rb
# frozen_string_literal: true
# rubocop:todo all
# Copyright (C) 2014-2020 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 Mongo
module Operation
class Aggregate
# Defines custom behavior of results in an aggregation context.
#
# @since 2.0.0
# @api semiprivate
class Result < Operation::Result
# The field name for the aggregation explain information.
#
# @since 2.0.5
# @api private
EXPLAIN = 'stages'.freeze
# The legacy field name for the aggregation explain information.
#
# @since 2.0.5
# @api private
EXPLAIN_LEGACY = 'serverPipeline'.freeze
# Get the cursor id for the result.
#
# @example Get the cursor id.
# result.cursor_id
#
# @note Even though the wire protocol has a cursor_id field for all
# messages of type reply, it is always zero when using the
# aggregation framework and must be retrieved from the cursor
# document itself. Wahnsinn!
#
# @return [ Integer ] The cursor id.
#
# @since 2.0.0
# @api private
def cursor_id
cursor_document ? cursor_document[CURSOR_ID] : 0
end
# Get the post batch resume token for the result
#
# @return [ BSON::Document | nil ] The post batch resume token
#
# @api private
def post_batch_resume_token
cursor_document ? cursor_document['postBatchResumeToken'] : nil
end
# Get the documents for the aggregation result. This is either the
# first document's 'result' field, or if a cursor option was selected,
# it is the 'firstBatch' field in the 'cursor' field of the first
# document returned. Otherwise, it is an explain document.
#
# @example Get the documents.
# result.documents
#
# @return [ Array<BSON::Document> ] The documents.
#
# @since 2.0.0
# @api public
def documents
docs = reply.documents[0][RESULT]
docs ||= cursor_document[FIRST_BATCH] if cursor_document
docs ||= explain_document
docs
end
private
# This should only be called on explain responses; it will never
# return a nil result and will only be meaningful on explain responses
def explain_document
first_document[EXPLAIN] || first_document[EXPLAIN_LEGACY] || [first_document]
end
def cursor_document
@cursor_document ||= reply.documents[0][CURSOR]
end
def first_document
@first_document ||= reply.documents[0]
end
end
end
end
end