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# frozen_string_literal: true
# rubocop:todo all
# Copyright (C) 2019-2020 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
# ClusterTime encapsulates cluster time storage and operations.
#
# The primary operation performed on the cluster time is advancing it:
# given another cluster time, pick the newer of the two.
#
# This class provides comparison methods that are used to figure out which
# cluster time is newer, and provides diagnostics in lint mode when
# the actual time is missing from a cluster time document.
#
# @api private
class ClusterTime < BSON::Document
def initialize(elements = nil)
super
if Lint.enabled? && !self['clusterTime']
raise ArgumentError, 'Creating a cluster time without clusterTime field'
end
end
# Advances the cluster time in the receiver to the cluster time in +other+.
#
# +other+ can be nil or be behind the cluster time in the receiver; in
# these cases the receiver is returned unmodified. If receiver is advanced,
# a new ClusterTime object is returned.
#
# Return value is nil or a ClusterTime instance.
def advance(other)
if self['clusterTime'] && other['clusterTime'] &&
other['clusterTime'] > self['clusterTime']
then
ClusterTime[other]
else
self
end
end
# Compares two ClusterTime instances by comparing their timestamps.
def <=>(other)
if self['clusterTime'] && other['clusterTime']
self['clusterTime'] <=> other['clusterTime']
elsif !self['clusterTime']
raise ArgumentError, "Cannot compare cluster times when receiver is missing clusterTime key: #{inspect}"
else other['clusterTime']
raise ArgumentError, "Cannot compare cluster times when other is missing clusterTime key: #{other.inspect}"
end
end
# Older Rubies do not implement other logical operators through <=>.
# TODO revise whether these methods are needed when
# https://jira.mongodb.org/browse/RUBY-1622 is implemented.
def >=(other)
(self <=> other) != -1
end
def >(other)
(self <=> other) == 1
end
def <=(other)
(self <=> other) != 1
end
def <(other)
(self <=> other) == -1
end
# Compares two ClusterTime instances by comparing their timestamps.
def ==(other)
if self['clusterTime'] && other['clusterTime'] &&
self['clusterTime'] == other['clusterTime']
then
true
else
false
end
end
class << self
# Converts a BSON::Document to a ClusterTime.
#
# +doc+ can be nil, in which case nil is returned.
def [](doc)
if doc.nil? || doc.is_a?(ClusterTime)
doc
else
ClusterTime.new(doc)
end
end
end
# This module provides common cluster time tracking behavior.
#
# @note Although attributes and methods defined in this module are part of
# the public API for the classes including this module, the fact that
# the methods are defined on this module and not directly on the
# including classes is not part of the public API.
module Consumer
# The cluster time tracked by the object including this module.
#
# @return [ nil | ClusterTime ] The cluster time.
#
# Changed in version 2.9.0: This attribute became an instance of
# ClusterTime, which is a subclass of BSON::Document.
# Previously it was an instance of BSON::Document.
#
# @since 2.5.0
attr_reader :cluster_time
# Advance the tracked cluster time document for the object including
# this module.
#
# @param [ BSON::Document ] new_cluster_time The new cluster time document.
#
# @return [ ClusterTime ] The resulting cluster time.
#
# @since 2.5.0
def advance_cluster_time(new_cluster_time)
if @cluster_time
@cluster_time = @cluster_time.advance(new_cluster_time)
else
@cluster_time = ClusterTime[new_cluster_time]
end
end
end
end
end
|
