Gtk And Ruby Threading Issues

In one of my classes, we used Ruby and Gtk, but some issues popped up. The most obvious is using a block to do GUI update stuff and the like, from another thread. Things die. Puppies are killed.

I found this post on Ruby Forum which fixed the problem.

Relevant code.

	require "thread"

	module Gtk
	# Thread-safety stuff.
	# Loosely based on booh, by Guillaume Cottenceau.

	PENDING_CALLS_MUTEX = Mutex.new
	PENDING_CALLS = []

	def self.thread_protect(&proc)
	if Thread.current == Thread.main
	proc.call
	else
	PENDING_CALLS_MUTEX.synchronize do
	PENDING_CALLS << proc
	end
	end
	end

	def self.thread_flush
	if PENDING_CALLS_MUTEX.try_lock
	for closure in PENDING_CALLS
	closure.call
	end
	PENDING_CALLS.clear
	PENDING_CALLS_MUTEX.unlock
	end
	end

	def self.init_thread_protect
	Gtk.timeout_add(100) do
	PENDING_CALLS_MUTEX.synchronize do
	for closure in PENDING_CALLS
	closure.call
	end
	PENDING_CALLS.clear
	end
	true
	end
	end
	end

view raw gtk.rb hosted with ❤ by GitHub

Basically, you call the Gtk.init_thread_protect method first when you start things up, then, whenever you need to do GUI update stuff, just wrap it in a Gtk.thread_protect {} block. Voila! It works. No more crashes. In looking at this code again now, some things could be made more Rubyesque, but we'll go with it.

My version with minor changes:

	require "thread"

	module Gtk
	PENDING_CALLS_MUTEX = Mutex.new
	PENDING_CALLS = []

	def self.thread_protect(&proc)
	if Thread.current == Thread.main
	proc.call
	else
	PENDING_CALLS_MUTEX.synchronize do
	PENDING_CALLS << proc
	end
	end
	end

	def self.thread_flush
	if PENDING_CALLS_MUTEX.try_lock
	PENDING_CALLS.each { \|closure\| closure.call }
	PENDING_CALLS.clear
	PENDING_CALLS_MUTEX.unlock
	end
	end

	def self.init_thread_protect
	Gtk.timeout_add(100) do
	PENDING_CALLS_MUTEX.synchronize do
	PENDING_CALLS.each { \|closure\| closure.call }
	PENDING_CALLS.clear
	end
	true
	end
	end
	end

view raw gtk-mod.rb hosted with ❤ by GitHub