lib/thread_safe/synchronized_delegator.rb
require 'delegate'
require 'monitor'
# This class provides a trivial way to synchronize all calls to a given object
# by wrapping it with a `Delegator` that performs `Monitor#enter/exit` calls
# around the delegated `#send`. Example:
#
# array = [] # not thread-safe on many impls
# array = SynchronizedDelegator.new([]) # thread-safe
#
# A simple `Monitor` provides a very coarse-grained way to synchronize a given
# object, in that it will cause synchronization for methods that have no need
# for it, but this is a trivial way to get thread-safety where none may exist
# currently on some implementations.
#
# This class is currently being considered for inclusion into stdlib, via
# https://bugs.ruby-lang.org/issues/8556
class SynchronizedDelegator < SimpleDelegator
def setup
@old_abort = Thread.abort_on_exception
Thread.abort_on_exception = true
end
def teardown
Thread.abort_on_exception = @old_abort
end
def initialize(obj)
__setobj__(obj)
@monitor = Monitor.new
end
def method_missing(method, *args, &block)
monitor = @monitor
begin
monitor.enter
super
ensure
monitor.exit
end
end
end unless defined?(SynchronizedDelegator)