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Contents
# frozen_string_literal: true
# Released under the MIT License.
# Copyright, 2018-2023, by Samuel Williams.
require_relative 'notification'
require 'thread'
module Async
module IO
# A cross-reactor/process notification pipe.
class Trap
def initialize(name)
@name = name
@notifications = []
@installed = false
@mutex = Mutex.new
end
def to_s
"\#<#{self.class} #{@name}>"
end
# Ignore the trap within the current process. Can be invoked before forking and/or invoking `install!` to assert default behaviour.
def ignore!
Signal.trap(@name, :IGNORE)
end
def default!
Signal.trap(@name, :DEFAULT)
end
# Install the trap into the current process. Thread safe.
# @return [Boolean] whether the trap was installed or not. If the trap was already installed, returns nil.
def install!
return if @installed
@mutex.synchronize do
return if @installed
Signal.trap(@name, &self.method(:trigger))
@installed = true
end
return true
end
# Wait until the signal occurs. If a block is given, execute in a loop.
# @yield [Async::Task] the current task.
def wait(task: Task.current, &block)
task.annotate("waiting for signal #{@name}")
notification = Notification.new
@notifications << notification
if block_given?
while true
notification.wait
yield task
end
else
notification.wait
end
ensure
if notification
notification.close
@notifications.delete(notification)
end
end
# Deprecated.
alias trap wait
# In order to avoid blocking the reactor, specify `transient: true` as an option.
def async(parent: Task.current, **options, &block)
parent.async(**options) do |task|
self.wait(task: task, &block)
end
end
# Signal all waiting tasks that the trap occurred.
# @return [void]
def trigger(signal_number = nil)
@notifications.each(&:signal)
end
end
end
end
Version data entries
12 entries across 12 versions & 1 rubygems