# frozen_string_literal: false
# Timeout long-running blocks
#
# == Synopsis
#
# require 'timeout'
# status = Timeout::timeout(5) {
# # Something that should be interrupted if it takes more than 5 seconds...
# }
#
# == Description
#
# Timeout provides a way to auto-terminate a potentially long-running
# operation if it hasn't finished in a fixed amount of time.
#
# Previous versions didn't use a module for namespacing, however
# #timeout is provided for backwards compatibility. You
# should prefer Timeout.timeout instead.
#
# == Copyright
#
# Copyright:: (C) 2000 Network Applied Communication Laboratory, Inc.
# Copyright:: (C) 2000 Information-technology Promotion Agency, Japan
module Timeout
VERSION = "0.2.0".freeze
# Raised by Timeout.timeout when the block times out.
class Error < RuntimeError
attr_reader :thread
def self.catch(*args)
exc = new(*args)
exc.instance_variable_set(:@thread, Thread.current)
exc.instance_variable_set(:@catch_value, exc)
::Kernel.catch(exc) {yield exc}
end
def exception(*)
# TODO: use Fiber.current to see if self can be thrown
if self.thread == Thread.current
bt = caller
begin
throw(@catch_value, bt)
rescue UncaughtThrowError
end
end
super
end
end
# :stopdoc:
THIS_FILE = /\A#{Regexp.quote(__FILE__)}:/o
CALLER_OFFSET = ((c = caller[0]) && THIS_FILE =~ c) ? 1 : 0
private_constant :THIS_FILE, :CALLER_OFFSET
# :startdoc:
# Perform an operation in a block, raising an error if it takes longer than
# +sec+ seconds to complete.
#
# +sec+:: Number of seconds to wait for the block to terminate. Any number
# may be used, including Floats to specify fractional seconds. A
# value of 0 or +nil+ will execute the block without any timeout.
# +klass+:: Exception Class to raise if the block fails to terminate
# in +sec+ seconds. Omitting will use the default, Timeout::Error
# +message+:: Error message to raise with Exception Class.
# Omitting will use the default, "execution expired"
#
# Returns the result of the block *if* the block completed before
# +sec+ seconds, otherwise throws an exception, based on the value of +klass+.
#
# The exception thrown to terminate the given block cannot be rescued inside
# the block unless +klass+ is given explicitly. However, the block can use
# ensure to prevent the handling of the exception. For that reason, this
# method cannot be relied on to enforce timeouts for untrusted blocks.
#
# If a scheduler is defined, it will be used to handle the timeout by invoking
# Scheduler#timeout_after.
#
# Note that this is both a method of module Timeout, so you can <tt>include
# Timeout</tt> into your classes so they have a #timeout method, as well as
# a module method, so you can call it directly as Timeout.timeout().
def timeout(sec, klass = nil, message = nil, &block) #:yield: +sec+
return yield(sec) if sec == nil or sec.zero?
message ||= "execution expired".freeze
if Fiber.respond_to?(:current_scheduler) && (scheduler = Fiber.current_scheduler)&.respond_to?(:timeout_after)
return scheduler.timeout_after(sec, klass || Error, message, &block)
end
from = "from #{caller_locations(1, 1)[0]}" if $DEBUG
e = Error
bl = proc do |exception|
begin
x = Thread.current
y = Thread.start {
Thread.current.name = from
begin
sleep sec
rescue => e
x.raise e
else
x.raise exception, message
end
}
return yield(sec)
ensure
if y
y.kill
y.join # make sure y is dead.
end
end
end
if klass
begin
bl.call(klass)
rescue klass => e
message = e.message
bt = e.backtrace
end
else
bt = Error.catch(message, &bl)
end
level = -caller(CALLER_OFFSET).size-2
while THIS_FILE =~ bt[level]
bt.delete_at(level)
end
raise(e, message, bt)
end
module_function :timeout
end
