# Very rudimentary test of threading module

import test.test_support

from test.test_support import verbose

import random

import sys

import threading

import thread

import time

import unittest

# A trivial mutable counter.

class Counter(object):

    def __init__(self):

        self.value = 0

    def inc(self):

        self.value += 1

    def dec(self):

        self.value -= 1

    def get(self):

        return self.value

class TestThread(threading.Thread):

    def __init__(self, name, testcase, sema, mutex, nrunning):

        threading.Thread.__init__(self, name=name)

        self.testcase = testcase

        self.sema = sema

        self.mutex = mutex

        self.nrunning = nrunning

    def run(self):

        delay = random.random() * 2

        if verbose:

            print 'task', self.getName(), 'will run for', delay, 'sec'

        self.sema.acquire()

        self.mutex.acquire()

        self.nrunning.inc()

        if verbose:

            print self.nrunning.get(), 'tasks are running'

        self.testcase.assert_(self.nrunning.get() <= 3)

        self.mutex.release()

        time.sleep(delay)

        if verbose:

            print 'task', self.getName(), 'done'

        self.mutex.acquire()

        self.nrunning.dec()

        self.testcase.assert_(self.nrunning.get() >= 0)

        if verbose:

            print self.getName(), 'is finished.', self.nrunning.get(), \

                  'tasks are running'

        self.mutex.release()

        self.sema.release()

class ThreadTests(unittest.TestCase):

    # Create a bunch of threads, let each do some work, wait until all are

    # done.

    def test_various_ops(self):

        # This takes about n/3 seconds to run (about n/3 clumps of tasks,

        # times about 1 second per clump).

        NUMTASKS = 10

        # no more than 3 of the 10 can run at once

        sema = threading.BoundedSemaphore(value=3)

        mutex = threading.RLock()

        numrunning = Counter()

        threads = []

        for i in range(NUMTASKS):

            t = TestThread("<thread %d>"%i, self, sema, mutex, numrunning)

            threads.append(t)

            t.start()

        if verbose:

            print 'waiting for all tasks to complete'

        for t in threads:

            t.join(NUMTASKS)

            self.assert_(not t.isAlive())

        if verbose:

            print 'all tasks done'

        self.assertEqual(numrunning.get(), 0)

    # run with a small(ish) thread stack size (256kB)

    def test_various_ops_small_stack(self):

        if verbose:

            print 'with 256kB thread stack size...'

        try:

            threading.stack_size(262144)

        except thread.error:

            if verbose:

                print 'platform does not support changing thread stack size'

            return

        self.test_various_ops()

        threading.stack_size(0)

    # run with a large thread stack size (1MB)

    def test_various_ops_large_stack(self):

        if verbose:

            print 'with 1MB thread stack size...'

        try:

            threading.stack_size(0x100000)

        except thread.error:

            if verbose:

                print 'platform does not support changing thread stack size'

            return

        self.test_various_ops()

        threading.stack_size(0)

    def test_foreign_thread(self):

        # Check that a "foreign" thread can use the threading module.

        def f(mutex):

            # Acquiring an RLock forces an entry for the foreign

            # thread to get made in the threading._active map.

            r = threading.RLock()

            r.acquire()

            r.release()

            mutex.release()

        mutex = threading.Lock()

        mutex.acquire()

        tid = thread.start_new_thread(f, (mutex,))

        # Wait for the thread to finish.

        mutex.acquire()

        self.assert_(tid in threading._active)

        self.assert_(isinstance(threading._active[tid],

                                threading._DummyThread))

        del threading._active[tid]

    # PyThreadState_SetAsyncExc() is a CPython-only gimmick, not (currently)

    # exposed at the Python level.  This test relies on ctypes to get at it.

    def test_PyThreadState_SetAsyncExc(self):

        try:

            import ctypes

        except ImportError:

            if verbose:

                print "test_PyThreadState_SetAsyncExc can't import ctypes"

            return  # can't do anything

        set_async_exc = ctypes.pythonapi.PyThreadState_SetAsyncExc

        class AsyncExc(Exception):

            pass

        exception = ctypes.py_object(AsyncExc)

        # `worker_started` is set by the thread when it's inside a try/except

        # block waiting to catch the asynchronously set AsyncExc exception.

        # `worker_saw_exception` is set by the thread upon catching that

        # exception.

        worker_started = threading.Event()

        worker_saw_exception = threading.Event()

        class Worker(threading.Thread):

            def run(self):

                self.id = thread.get_ident()

                self.finished = False

                try:

                    while True:

                        worker_started.set()

                        time.sleep(0.1)

                except AsyncExc:

                    self.finished = True

                    worker_saw_exception.set()

        t = Worker()

        t.setDaemon(True) # so if this fails, we don't hang Python at shutdown

        t.start()

        if verbose:

            print "    started worker thread"

        # Try a thread id that doesn't make sense.

        if verbose:

            print "    trying nonsensical thread id"

        result = set_async_exc(ctypes.c_long(-1), exception)

        self.assertEqual(result, 0)  # no thread states modified

        # Now raise an exception in the worker thread.

        if verbose:

            print "    waiting for worker thread to get started"

        worker_started.wait()

        if verbose:

            print "    verifying worker hasn't exited"

        self.assert_(not t.finished)

        if verbose:

            print "    attempting to raise asynch exception in worker"

        result = set_async_exc(ctypes.c_long(t.id), exception)

        self.assertEqual(result, 1) # one thread state modified

        if verbose:

            print "    waiting for worker to say it caught the exception"

        worker_saw_exception.wait(timeout=10)

        self.assert_(t.finished)

        if verbose:

            print "    all OK -- joining worker"

        if t.finished:

            t.join()

        # else the thread is still running, and we have no way to kill it

    def test_enumerate_after_join(self):

        # Try hard to trigger #1703448: a thread is still returned in

        # threading.enumerate() after it has been join()ed.

        enum = threading.enumerate

        old_interval = sys.getcheckinterval()

        sys.setcheckinterval(1)

        try:

            for i in xrange(1, 1000):

                t = threading.Thread(target=lambda: None)

                t.start()

                t.join()

                l = enum()

                self.assertFalse(t in l,

                    "#1703448 triggered after %d trials: %s" % (i, l))

        finally:

            sys.setcheckinterval(old_interval)

def test_main():

    test.test_support.run_unittest(ThreadTests)

if __name__ == "__main__":

    test_main()