JezK
Edit File: rinda.rb
# frozen_string_literal: false require 'drb/drb' ## # A module to implement the Linda distributed computing paradigm in Ruby. # # Rinda is part of DRb (dRuby). # # == Example(s) # # See the sample/drb/ directory in the Ruby distribution, from 1.8.2 onwards. # #-- # TODO # == Introduction to Linda/rinda? # # == Why is this library separate from DRb? module Rinda ## # Rinda error base class class RindaError < RuntimeError; end ## # Raised when a hash-based tuple has an invalid key. class InvalidHashTupleKey < RindaError; end ## # Raised when trying to use a canceled tuple. class RequestCanceledError < ThreadError; end ## # Raised when trying to use an expired tuple. class RequestExpiredError < ThreadError; end ## # A tuple is the elementary object in Rinda programming. # Tuples may be matched against templates if the tuple and # the template are the same size. class Tuple ## # Creates a new Tuple from +ary_or_hash+ which must be an Array or Hash. def initialize(ary_or_hash) if hash?(ary_or_hash) init_with_hash(ary_or_hash) else init_with_ary(ary_or_hash) end end ## # The number of elements in the tuple. def size @tuple.size end ## # Accessor method for elements of the tuple. def [](k) @tuple[k] end ## # Fetches item +k+ from the tuple. def fetch(k) @tuple.fetch(k) end ## # Iterate through the tuple, yielding the index or key, and the # value, thus ensuring arrays are iterated similarly to hashes. def each # FIXME if Hash === @tuple @tuple.each { |k, v| yield(k, v) } else @tuple.each_with_index { |v, k| yield(k, v) } end end ## # Return the tuple itself def value @tuple end private def hash?(ary_or_hash) ary_or_hash.respond_to?(:keys) end ## # Munges +ary+ into a valid Tuple. def init_with_ary(ary) @tuple = Array.new(ary.size) @tuple.size.times do |i| @tuple[i] = ary[i] end end ## # Ensures +hash+ is a valid Tuple. def init_with_hash(hash) @tuple = Hash.new hash.each do |k, v| raise InvalidHashTupleKey unless String === k @tuple[k] = v end end end ## # Templates are used to match tuples in Rinda. class Template < Tuple ## # Matches this template against +tuple+. The +tuple+ must be the same # size as the template. An element with a +nil+ value in a template acts # as a wildcard, matching any value in the corresponding position in the # tuple. Elements of the template match the +tuple+ if the are #== or # #===. # # Template.new([:foo, 5]).match Tuple.new([:foo, 5]) # => true # Template.new([:foo, nil]).match Tuple.new([:foo, 5]) # => true # Template.new([String]).match Tuple.new(['hello']) # => true # # Template.new([:foo]).match Tuple.new([:foo, 5]) # => false # Template.new([:foo, 6]).match Tuple.new([:foo, 5]) # => false # Template.new([:foo, nil]).match Tuple.new([:foo]) # => false # Template.new([:foo, 6]).match Tuple.new([:foo]) # => false def match(tuple) return false unless tuple.respond_to?(:size) return false unless tuple.respond_to?(:fetch) return false unless self.size == tuple.size each do |k, v| begin it = tuple.fetch(k) rescue return false end next if v.nil? next if v == it next if v === it return false end return true end ## # Alias for #match. def ===(tuple) match(tuple) end end ## # <i>Documentation?</i> class DRbObjectTemplate ## # Creates a new DRbObjectTemplate that will match against +uri+ and +ref+. def initialize(uri=nil, ref=nil) @drb_uri = uri @drb_ref = ref end ## # This DRbObjectTemplate matches +ro+ if the remote object's drburi and # drbref are the same. +nil+ is used as a wildcard. def ===(ro) return true if super(ro) unless @drb_uri.nil? return false unless (@drb_uri === ro.__drburi rescue false) end unless @drb_ref.nil? return false unless (@drb_ref === ro.__drbref rescue false) end true end end ## # TupleSpaceProxy allows a remote Tuplespace to appear as local. class TupleSpaceProxy ## # A Port ensures that a moved tuple arrives properly at its destination # and does not get lost. # # See https://bugs.ruby-lang.org/issues/8125 class Port # :nodoc: attr_reader :value def self.deliver port = new begin yield(port) ensure port.close end port.value end def initialize @open = true @value = nil end ## # Don't let the DRb thread push to it when remote sends tuple def close @open = false end ## # Stores +value+ and ensure it does not get marshaled multiple times. def push value raise 'port closed' unless @open @value = value nil # avoid Marshal end end ## # Creates a new TupleSpaceProxy to wrap +ts+. def initialize(ts) @ts = ts end ## # Adds +tuple+ to the proxied TupleSpace. See TupleSpace#write. def write(tuple, sec=nil) @ts.write(tuple, sec) end ## # Takes +tuple+ from the proxied TupleSpace. See TupleSpace#take. def take(tuple, sec=nil, &block) Port.deliver do |port| @ts.move(DRbObject.new(port), tuple, sec, &block) end end ## # Reads +tuple+ from the proxied TupleSpace. See TupleSpace#read. def read(tuple, sec=nil, &block) @ts.read(tuple, sec, &block) end ## # Reads all tuples matching +tuple+ from the proxied TupleSpace. See # TupleSpace#read_all. def read_all(tuple) @ts.read_all(tuple) end ## # Registers for notifications of event +ev+ on the proxied TupleSpace. # See TupleSpace#notify def notify(ev, tuple, sec=nil) @ts.notify(ev, tuple, sec) end end ## # An SimpleRenewer allows a TupleSpace to check if a TupleEntry is still # alive. class SimpleRenewer include DRbUndumped ## # Creates a new SimpleRenewer that keeps an object alive for another +sec+ # seconds. def initialize(sec=180) @sec = sec end ## # Called by the TupleSpace to check if the object is still alive. def renew @sec end end end