# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
# 
#   http://www.apache.org/licenses/LICENSE-2.0
# 
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.    

import threading
import time
import Queue
import logging

_log = logging.getLogger('tashi.parallel')

def threaded(func):
	def fn(*args, **kwargs):
		thread = threading.Thread(target=func, args=args, kwargs=kwargs)
		thread.start()
		return thread
	return fn


class ThreadPool(Queue.Queue):
	def __init__(self, size=8, maxsize=0):
		Queue.Queue.__init__(self, maxsize)
		for i in range(size):
			thread = threading.Thread(target=self._worker)
			thread.setDaemon(True)
			thread.start()
	def _worker(self):
		while True:
			try:
				func, args, kwargs = self.get()
				func(*args, **kwargs)
			except Exception, e:
				_log.error(e)
				# FIXME: do something smarter here, backtrace, log,
				# allow user-defined error handling...
				
	def submit(self, func, *args, **kwargs):
		self.put((func, args, kwargs))
	def submitlist(self, func, args, kwargs):
		self.put((func, args, kwargs))

class ThreadPoolClass:
	def __init__(self, size=8, maxsize=0):
		self._threadpool_pool = ThreadPool(size=size, maxsize=maxsize)


def threadpool(pool):
	def dec(func):
		def fn(*args, **kwargs):
			pool.submit(func, *args, **kwargs)
		return fn
	return dec

def threadpoolmethod(meth):
	def fn(*args, **kwargs):
		try:
			pool = args[0]._threadpool_pool
		except AttributeError:
			pool = args[0].__dict__.setdefault('_threadpool_pool', ThreadPool())
		# FIXME: how do we check parent class?
#		assert args[0].__class__ == ThreadPoolClass, "Thread pool method must be in a ThreadPoolClass"
		pool.submit(meth, *args, **kwargs)
	return fn

def synchronized(lock=None):
	if lock==None:
		lock = threading.RLock()
	def dec(func):
		def fn(*args, **kwargs):
			lock.acquire()
			ex = None
			try:
				r = func(*args, **kwargs)
			except Exception, e:
				ex = e
			lock.release()
			if ex != None:
				raise e
			return r
		return fn
	return dec
			
def synchronizedmethod(func):
	def fn(*args, **kwargs):
		try:
			lock = args[0]._synchronized_lock
		except AttributeError:
			lock = args[0].__dict__.setdefault('_synchronized_lock', threading.RLock())
		lock.acquire()
		ex = None
		try:
			res = func(*args, **kwargs)
		except Exception, e:
			ex = e
		lock.release()
		if ex != None:
			raise e
		return res
	return fn
		

##############################
# Test Code
##############################
import unittest
#import sys
#import time

class TestThreadPool(unittest.TestCase):
	def setUp(self):
		self.errmargin = 0.5

	def testUnthreaded(self):
		queue = Queue.Queue()
		def slowfunc(sleep=1):
			time.sleep(sleep)
			queue.put(None)
		tt = time.time()
		for i in range(4):
			slowfunc()
		for i in range(4):
			queue.get()
		tt = time.time() - tt
		self.assertAlmostEqual(tt, 4, 1) 

	def testThreaded(self):
		queue = Queue.Queue()
		@threaded
		def slowthreadfunc(sleep=1):
			time.sleep(sleep)
			queue.put(None)
		tt = time.time()
		for i in range(8):
			slowthreadfunc()
		for i in range(8):
			queue.get()
		tt = time.time() - tt
		self.assertAlmostEqual(tt, 1, 1) 

	def testThreadPool(self):
		pool = ThreadPool(size=4)
		queue = Queue.Queue()
		@threadpool(pool)
		def slowpoolfunc(sleep=1):
			time.sleep(sleep)
			queue.put(None)
		tt = time.time()
		for i in range(8):
			slowpoolfunc()
		for i in range(8):
			queue.get()
		tt = time.time() - tt
		self.assertAlmostEqual(tt, 2, 1) 

	def testUnthreadedMethod(self):
		queue = Queue.Queue()
		class slowclass:
			def __init__(self, sleep=1):
				self.sleep=sleep
			def beslow(self):
				time.sleep(self.sleep)
				queue.put(None)
		sc = slowclass()
		tt = time.time()
		for i in range(4):
			sc.beslow()
		for i in range(4):
			queue.get()
		tt = time.time() - tt
		self.assertAlmostEqual(tt, 4, 1)
	
	def testThreadedMethod(self):
		queue = Queue.Queue()
		class slowclass:
			def __init__(self, sleep=1):
				self.sleep=sleep
			@threaded
			def beslow(self):
				time.sleep(self.sleep)
				queue.put(None)
		sc = slowclass()
		tt = time.time()
		for i in range(4):
			sc.beslow()
		for i in range(4):
			queue.get()
		tt = time.time() - tt
		self.assertAlmostEqual(tt, 1, 1)
	
	def testThreadPoolMethod(self):
		queue = Queue.Queue()
		class slowclass:
			def __init__(self, sleep=1):
				self.sleep=sleep
			@threadpoolmethod
			def beslow(self):
				time.sleep(self.sleep)
				queue.put(None)
		sc = slowclass()
		tt = time.time()
		for i in range(16):
			sc.beslow()
		for i in range(16):
			queue.get()
		tt = time.time() - tt
		self.assertAlmostEqual(tt, 2, 1)
	
	def testSynchronized(self):
		queue = Queue.Queue()
		@synchronized()
		def addtoqueue():
			time.sleep(1)
			queue.put(None)
		@threaded
		def slowthreadfunc():
			addtoqueue()
		tt = time.time()
		for i in range(4):
			slowthreadfunc()
		for i in range(4):
			queue.get()
		tt = time.time() - tt
		self.assertAlmostEqual(tt, 4, 1) 

	def testSynchronizedMethod(self):
		queue = Queue.Queue()
		class addtoqueue:
			@synchronizedmethod
			def addtoqueue1(self):
				time.sleep(1)
				queue.put(None)
			@synchronizedmethod
			def addtoqueue2(self):
				time.sleep(1)
				queue.put(None)
		atc = addtoqueue()
		@threaded
		def slowthreadfunc1():
			atc.addtoqueue1()
		@threaded
		def slowthreadfunc2():
			atc.addtoqueue2()
		tt = time.time()
		for i in range(4):
			slowthreadfunc1()
			slowthreadfunc2()
		for i in range(8):
			queue.get()
		tt = time.time() - tt
		self.assertAlmostEqual(tt, 8, 1) 

	def testUnsynchronizedMethod(self):
		queue = Queue.Queue()
		class addtoqueue:
			def addtoqueue1(self):
				time.sleep(1)
				queue.put(None)
			def addtoqueue2(self):
				time.sleep(1)
				queue.put(None)
		atc = addtoqueue()
		@threaded
		def slowthreadfunc1():
			atc.addtoqueue1()
		@threaded
		def slowthreadfunc2():
			atc.addtoqueue2()
		tt = time.time()
		for i in range(4):
			slowthreadfunc1()
			slowthreadfunc2()
		for i in range(8):
			queue.get()
		tt = time.time() - tt
		self.assertAlmostEqual(tt, 1, 1) 


if __name__=='__main__':
	import sys

	logging.basicConfig(level=logging.INFO,
	                    format="%(asctime)s %(levelname)s:\t %(message)s",
	                    stream=sys.stdout)

	suite = unittest.TestLoader().loadTestsFromTestCase(TestThreadPool)
	unittest.TextTestRunner(verbosity=2).run(suite)