#! /usr/bin/env python

"""
Task semaphore demo. Compare the runtimes:

	waf configure build --fast  # 0m08
	waf configure build         # 1m15
"""

import random, time
from waflib import Task, TaskGen, Utils

def options(opt):
	opt.add_option('--fast', action='store_true', default=False, help='Disable the semaphore to compare the runtime', dest='fast')

def configure(conf):
	pass

def build(bld):
	# max 20 jobs globally
	bld.jobs = 20

	bld(features='make_100')

	class Foo(Task.Task):
		always_run = True

		if not bld.options.fast:
			semaphore = Task.TaskSemaphore(2) # 2 jobs maximum

		def uid(self):
			# unique id for each object
			return Utils.h_list(self.num)

		def run(self):
			time.sleep(random.randint(1000, 2000) / 1000.)
			print("Task %r" % self.num)

	@TaskGen.feature('make_100')
	def make_100_bound_tasks(self):
		for x in range(100):
			tsk = self.create_task('Foo')
			tsk.num = x