diff options
Diffstat (limited to 'lib/timeout.rb')
| -rw-r--r-- | lib/timeout.rb | 266 |
1 files changed, 182 insertions, 84 deletions
diff --git a/lib/timeout.rb b/lib/timeout.rb index dc92964c0b..7f40bafa4d 100644 --- a/lib/timeout.rb +++ b/lib/timeout.rb @@ -1,105 +1,203 @@ -#-- -# = timeout.rb +# frozen_string_literal: true +# Timeout long-running blocks # -# execution timeout +# == Synopsis # -# = Copyright -# -# Copyright:: (C) 2000 Network Applied Communication Laboratory, Inc. -# Copyright:: (C) 2000 Information-technology Promotion Agency, Japan -# -#++ -# -# = Description +# require 'timeout' +# status = Timeout::timeout(5) { +# # Something that should be interrupted if it takes more than 5 seconds... +# } # -# A way of performing a potentially long-running operation in a thread, and -# terminating it's execution if it hasn't finished within fixed amount of -# time. +# == Description # -# Previous versions of timeout didn't use a module for namespace. This version -# provides both Timeout.timeout, and a backwards-compatible #timeout. +# Timeout provides a way to auto-terminate a potentially long-running +# operation if it hasn't finished in a fixed amount of time. # -# = Synopsis +# Previous versions didn't use a module for namespacing, however +# #timeout is provided for backwards compatibility. You +# should prefer Timeout.timeout instead. # -# require 'timeout' -# status = Timeout::timeout(5) { -# # Something that should be interrupted if it takes too much time... -# } +# == Copyright # +# Copyright:: (C) 2000 Network Applied Communication Laboratory, Inc. +# Copyright:: (C) 2000 Information-technology Promotion Agency, Japan module Timeout + VERSION = "0.3.1" - ## - # Raised by Timeout#timeout when the block times out. + # Raised by Timeout.timeout when the block times out. + class Error < RuntimeError + attr_reader :thread - class Error<Interrupt + 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 - ## - # Executes the method's block. If the block execution terminates before +sec+ - # seconds has passed, it returns true. If not, it terminates the execution - # and raises +exception+ (which defaults to Timeout::Error). - # - # Note that this is both a method of module Timeout, so you can 'include - # Timeout' 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, exception=Error) - return yield if sec == nil or sec.zero? - raise ThreadError, "timeout within critical session" if Thread.critical - begin - x = Thread.current - y = Thread.start { - sleep sec - x.raise exception, "execution expired" if x.alive? - } - yield sec - # return true - ensure - y.kill if y and y.alive? + # :stopdoc: + CONDVAR = ConditionVariable.new + QUEUE = Queue.new + QUEUE_MUTEX = Mutex.new + TIMEOUT_THREAD_MUTEX = Mutex.new + @timeout_thread = nil + private_constant :CONDVAR, :QUEUE, :QUEUE_MUTEX, :TIMEOUT_THREAD_MUTEX + + class Request + attr_reader :deadline + + def initialize(thread, timeout, exception_class, message) + @thread = thread + @deadline = GET_TIME.call(Process::CLOCK_MONOTONIC) + timeout + @exception_class = exception_class + @message = message + + @mutex = Mutex.new + @done = false # protected by @mutex + end + + def done? + @mutex.synchronize do + @done + end + end + + def expired?(now) + now >= @deadline + end + + def interrupt + @mutex.synchronize do + unless @done + @thread.raise @exception_class, @message + @done = true + end + end + end + + def finished + @mutex.synchronize do + @done = true + end end end + private_constant :Request - module_function :timeout + def self.create_timeout_thread + watcher = Thread.new do + requests = [] + while true + until QUEUE.empty? and !requests.empty? # wait to have at least one request + req = QUEUE.pop + requests << req unless req.done? + end + closest_deadline = requests.min_by(&:deadline).deadline -end + now = 0.0 + QUEUE_MUTEX.synchronize do + while (now = GET_TIME.call(Process::CLOCK_MONOTONIC)) < closest_deadline and QUEUE.empty? + CONDVAR.wait(QUEUE_MUTEX, closest_deadline - now) + end + end -## -# Identical to: -# -# Timeout::timeout(n, e, &block). -# -# Defined for backwards compatibility with earlier versions of timeout.rb, see -# Timeout#timeout. + requests.each do |req| + req.interrupt if req.expired?(now) + end + requests.reject!(&:done?) + end + end + ThreadGroup::Default.add(watcher) + watcher.name = "Timeout stdlib thread" + watcher.thread_variable_set(:"\0__detached_thread__", true) + watcher + end + private_class_method :create_timeout_thread -def timeout(n, e=Timeout::Error, &block) # :nodoc: - Timeout::timeout(n, e, &block) -end + def self.ensure_timeout_thread_created + unless @timeout_thread and @timeout_thread.alive? + TIMEOUT_THREAD_MUTEX.synchronize do + unless @timeout_thread and @timeout_thread.alive? + @timeout_thread = create_timeout_thread + end + end + end + end -## -# Another name for Timeout::Error, defined for backwards compatibility with -# earlier versions of timeout.rb. - -TimeoutError = Timeout::Error # :nodoc: - -if __FILE__ == $0 - p timeout(5) { - 45 - } - p timeout(5, TimeoutError) { - 45 - } - p timeout(nil) { - 54 - } - p timeout(0) { - 54 - } - p timeout(5) { - loop { - p 10 - sleep 1 - } - } -end + # We keep a private reference so that time mocking libraries won't break + # Timeout. + GET_TIME = Process.method(:clock_gettime) + private_constant :GET_TIME + # :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" + + if Fiber.respond_to?(:current_scheduler) && (scheduler = Fiber.current_scheduler)&.respond_to?(:timeout_after) + return scheduler.timeout_after(sec, klass || Error, message, &block) + end + + Timeout.ensure_timeout_thread_created + perform = Proc.new do |exc| + request = Request.new(Thread.current, sec, exc, message) + QUEUE_MUTEX.synchronize do + QUEUE << request + CONDVAR.signal + end + begin + return yield(sec) + ensure + request.finished + end + end + + if klass + perform.call(klass) + else + backtrace = Error.catch(&perform) + raise Error, message, backtrace + end + end + module_function :timeout +end |