# Licensed 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.


from __future__ import absolute_import, division, print_function
from datetime import timedelta

from tornado import gen, locks
from tornado.gen import TimeoutError
from tornado.testing import gen_test, AsyncTestCase
from tornado.test.util import unittest, skipBefore35, exec_test


class ConditionTest(AsyncTestCase):
    def setUp(self):
        super(ConditionTest, self).setUp()
        self.history = []

    def record_done(self, future, key):
        """Record the resolution of a Future returned by Condition.wait."""
        def callback(_):
            if not future.result():
                # wait() resolved to False, meaning it timed out.
                self.history.append('timeout')
            else:
                self.history.append(key)
        future.add_done_callback(callback)

    def loop_briefly(self):
        """Run all queued callbacks on the IOLoop.

        In these tests, this method is used after calling notify() to
        preserve the pre-5.0 behavior in which callbacks ran
        synchronously.
        """
        self.io_loop.add_callback(self.stop)
        self.wait()

    def test_repr(self):
        c = locks.Condition()
        self.assertIn('Condition', repr(c))
        self.assertNotIn('waiters', repr(c))
        c.wait()
        self.assertIn('waiters', repr(c))

    @gen_test
    def test_notify(self):
        c = locks.Condition()
        self.io_loop.call_later(0.01, c.notify)
        yield c.wait()

    def test_notify_1(self):
        c = locks.Condition()
        self.record_done(c.wait(), 'wait1')
        self.record_done(c.wait(), 'wait2')
        c.notify(1)
        self.loop_briefly()
        self.history.append('notify1')
        c.notify(1)
        self.loop_briefly()
        self.history.append('notify2')
        self.assertEqual(['wait1', 'notify1', 'wait2', 'notify2'],
                         self.history)

    def test_notify_n(self):
        c = locks.Condition()
        for i in range(6):
            self.record_done(c.wait(), i)

        c.notify(3)
        self.loop_briefly()

        # Callbacks execute in the order they were registered.
        self.assertEqual(list(range(3)), self.history)
        c.notify(1)
        self.loop_briefly()
        self.assertEqual(list(range(4)), self.history)
        c.notify(2)
        self.loop_briefly()
        self.assertEqual(list(range(6)), self.history)

    def test_notify_all(self):
        c = locks.Condition()
        for i in range(4):
            self.record_done(c.wait(), i)

        c.notify_all()
        self.loop_briefly()
        self.history.append('notify_all')

        # Callbacks execute in the order they were registered.
        self.assertEqual(
            list(range(4)) + ['notify_all'],
            self.history)

    @gen_test
    def test_wait_timeout(self):
        c = locks.Condition()
        wait = c.wait(timedelta(seconds=0.01))
        self.io_loop.call_later(0.02, c.notify)  # Too late.
        yield gen.sleep(0.03)
        self.assertFalse((yield wait))

    @gen_test
    def test_wait_timeout_preempted(self):
        c = locks.Condition()

        # This fires before the wait times out.
        self.io_loop.call_later(0.01, c.notify)
        wait = c.wait(timedelta(seconds=0.02))
        yield gen.sleep(0.03)
        yield wait  # No TimeoutError.

    @gen_test
    def test_notify_n_with_timeout(self):
        # Register callbacks 0, 1, 2, and 3. Callback 1 has a timeout.
        # Wait for that timeout to expire, then do notify(2) and make
        # sure everyone runs. Verifies that a timed-out callback does
        # not count against the 'n' argument to notify().
        c = locks.Condition()
        self.record_done(c.wait(), 0)
        self.record_done(c.wait(timedelta(seconds=0.01)), 1)
        self.record_done(c.wait(), 2)
        self.record_done(c.wait(), 3)

        # Wait for callback 1 to time out.
        yield gen.sleep(0.02)
        self.assertEqual(['timeout'], self.history)

        c.notify(2)
        yield gen.sleep(0.01)
        self.assertEqual(['timeout', 0, 2], self.history)
        self.assertEqual(['timeout', 0, 2], self.history)
        c.notify()
        yield
        self.assertEqual(['timeout', 0, 2, 3], self.history)

    @gen_test
    def test_notify_all_with_timeout(self):
        c = locks.Condition()
        self.record_done(c.wait(), 0)
        self.record_done(c.wait(timedelta(seconds=0.01)), 1)
        self.record_done(c.wait(), 2)

        # Wait for callback 1 to time out.
        yield gen.sleep(0.02)
        self.assertEqual(['timeout'], self.history)

        c.notify_all()
        yield
        self.assertEqual(['timeout', 0, 2], self.history)

    @gen_test
    def test_nested_notify(self):
        # Ensure no notifications lost, even if notify() is reentered by a
        # waiter calling notify().
        c = locks.Condition()

        # Three waiters.
        futures = [c.wait() for _ in range(3)]

        # First and second futures resolved. Second future reenters notify(),
        # resolving third future.
        futures[1].add_done_callback(lambda _: c.notify())
        c.notify(2)
        yield
        self.assertTrue(all(f.done() for f in futures))

    @gen_test
    def test_garbage_collection(self):
        # Test that timed-out waiters are occasionally cleaned from the queue.
        c = locks.Condition()
        for _ in range(101):
            c.wait(timedelta(seconds=0.01))

        future = c.wait()
        self.assertEqual(102, len(c._waiters))

        # Let first 101 waiters time out, triggering a collection.
        yield gen.sleep(0.02)
        self.assertEqual(1, len(c._waiters))

        # Final waiter is still active.
        self.assertFalse(future.done())
        c.notify()
        self.assertTrue(future.done())


class EventTest(AsyncTestCase):
    def test_repr(self):
        event = locks.Event()
        self.assertTrue('clear' in str(event))
        self.assertFalse('set' in str(event))
        event.set()
        self.assertFalse('clear' in str(event))
        self.assertTrue('set' in str(event))

    def test_event(self):
        e = locks.Event()
        future_0 = e.wait()
        e.set()
        future_1 = e.wait()
        e.clear()
        future_2 = e.wait()

        self.assertTrue(future_0.done())
        self.assertTrue(future_1.done())
        self.assertFalse(future_2.done())

    @gen_test
    def test_event_timeout(self):
        e = locks.Event()
        with self.assertRaises(TimeoutError):
            yield e.wait(timedelta(seconds=0.01))

        # After a timed-out waiter, normal operation works.
        self.io_loop.add_timeout(timedelta(seconds=0.01), e.set)
        yield e.wait(timedelta(seconds=1))

    def test_event_set_multiple(self):
        e = locks.Event()
        e.set()
        e.set()
        self.assertTrue(e.is_set())

    def test_event_wait_clear(self):
        e = locks.Event()
        f0 = e.wait()
        e.clear()
        f1 = e.wait()
        e.set()
        self.assertTrue(f0.done())
        self.assertTrue(f1.done())


class SemaphoreTest(AsyncTestCase):
    def test_negative_value(self):
        self.assertRaises(ValueError, locks.Semaphore, value=-1)

    def test_repr(self):
        sem = locks.Semaphore()
        self.assertIn('Semaphore', repr(sem))
        self.assertIn('unlocked,value:1', repr(sem))
        sem.acquire()
        self.assertIn('locked', repr(sem))
        self.assertNotIn('waiters', repr(sem))
        sem.acquire()
        self.assertIn('waiters', repr(sem))

    def test_acquire(self):
        sem = locks.Semaphore()
        f0 = sem.acquire()
        self.assertTrue(f0.done())

        # Wait for release().
        f1 = sem.acquire()
        self.assertFalse(f1.done())
        f2 = sem.acquire()
        sem.release()
        self.assertTrue(f1.done())
        self.assertFalse(f2.done())
        sem.release()
        self.assertTrue(f2.done())

        sem.release()
        # Now acquire() is instant.
        self.assertTrue(sem.acquire().done())
        self.assertEqual(0, len(sem._waiters))

    @gen_test
    def test_acquire_timeout(self):
        sem = locks.Semaphore(2)
        yield sem.acquire()
        yield sem.acquire()
        acquire = sem.acquire(timedelta(seconds=0.01))
        self.io_loop.call_later(0.02, sem.release)  # Too late.
        yield gen.sleep(0.3)
        with self.assertRaises(gen.TimeoutError):
            yield acquire

        sem.acquire()
        f = sem.acquire()
        self.assertFalse(f.done())
        sem.release()
        self.assertTrue(f.done())

    @gen_test
    def test_acquire_timeout_preempted(self):
        sem = locks.Semaphore(1)
        yield sem.acquire()

        # This fires before the wait times out.
        self.io_loop.call_later(0.01, sem.release)
        acquire = sem.acquire(timedelta(seconds=0.02))
        yield gen.sleep(0.03)
        yield acquire  # No TimeoutError.

    def test_release_unacquired(self):
        # Unbounded releases are allowed, and increment the semaphore's value.
        sem = locks.Semaphore()
        sem.release()
        sem.release()

        # Now the counter is 3. We can acquire three times before blocking.
        self.assertTrue(sem.acquire().done())
        self.assertTrue(sem.acquire().done())
        self.assertTrue(sem.acquire().done())
        self.assertFalse(sem.acquire().done())

    @gen_test
    def test_garbage_collection(self):
        # Test that timed-out waiters are occasionally cleaned from the queue.
        sem = locks.Semaphore(value=0)
        futures = [sem.acquire(timedelta(seconds=0.01)) for _ in range(101)]

        future = sem.acquire()
        self.assertEqual(102, len(sem._waiters))

        # Let first 101 waiters time out, triggering a collection.
        yield gen.sleep(0.02)
        self.assertEqual(1, len(sem._waiters))

        # Final waiter is still active.
        self.assertFalse(future.done())
        sem.release()
        self.assertTrue(future.done())

        # Prevent "Future exception was never retrieved" messages.
        for future in futures:
            self.assertRaises(TimeoutError, future.result)


class SemaphoreContextManagerTest(AsyncTestCase):
    @gen_test
    def test_context_manager(self):
        sem = locks.Semaphore()
        with (yield sem.acquire()) as yielded:
            self.assertTrue(yielded is None)

        # Semaphore was released and can be acquired again.
        self.assertTrue(sem.acquire().done())

    @skipBefore35
    @gen_test
    def test_context_manager_async_await(self):
        # Repeat the above test using 'async with'.
        sem = locks.Semaphore()

        namespace = exec_test(globals(), locals(), """
        async def f():
            async with sem as yielded:
                self.assertTrue(yielded is None)
        """)
        yield namespace['f']()

        # Semaphore was released and can be acquired again.
        self.assertTrue(sem.acquire().done())

    @gen_test
    def test_context_manager_exception(self):
        sem = locks.Semaphore()
        with self.assertRaises(ZeroDivisionError):
            with (yield sem.acquire()):
                1 / 0

        # Semaphore was released and can be acquired again.
        self.assertTrue(sem.acquire().done())

    @gen_test
    def test_context_manager_timeout(self):
        sem = locks.Semaphore()
        with (yield sem.acquire(timedelta(seconds=0.01))):
            pass

        # Semaphore was released and can be acquired again.
        self.assertTrue(sem.acquire().done())

    @gen_test
    def test_context_manager_timeout_error(self):
        sem = locks.Semaphore(value=0)
        with self.assertRaises(gen.TimeoutError):
            with (yield sem.acquire(timedelta(seconds=0.01))):
                pass

        # Counter is still 0.
        self.assertFalse(sem.acquire().done())

    @gen_test
    def test_context_manager_contended(self):
        sem = locks.Semaphore()
        history = []

        @gen.coroutine
        def f(index):
            with (yield sem.acquire()):
                history.append('acquired %d' % index)
                yield gen.sleep(0.01)
                history.append('release %d' % index)

        yield [f(i) for i in range(2)]

        expected_history = []
        for i in range(2):
            expected_history.extend(['acquired %d' % i, 'release %d' % i])

        self.assertEqual(expected_history, history)

    @gen_test
    def test_yield_sem(self):
        # Ensure we catch a "with (yield sem)", which should be
        # "with (yield sem.acquire())".
        with self.assertRaises(gen.BadYieldError):
            with (yield locks.Semaphore()):
                pass

    def test_context_manager_misuse(self):
        # Ensure we catch a "with sem", which should be
        # "with (yield sem.acquire())".
        with self.assertRaises(RuntimeError):
            with locks.Semaphore():
                pass


class BoundedSemaphoreTest(AsyncTestCase):
    def test_release_unacquired(self):
        sem = locks.BoundedSemaphore()
        self.assertRaises(ValueError, sem.release)
        # Value is 0.
        sem.acquire()
        # Block on acquire().
        future = sem.acquire()
        self.assertFalse(future.done())
        sem.release()
        self.assertTrue(future.done())
        # Value is 1.
        sem.release()
        self.assertRaises(ValueError, sem.release)


class LockTests(AsyncTestCase):
    def test_repr(self):
        lock = locks.Lock()
        # No errors.
        repr(lock)
        lock.acquire()
        repr(lock)

    def test_acquire_release(self):
        lock = locks.Lock()
        self.assertTrue(lock.acquire().done())
        future = lock.acquire()
        self.assertFalse(future.done())
        lock.release()
        self.assertTrue(future.done())

    @gen_test
    def test_acquire_fifo(self):
        lock = locks.Lock()
        self.assertTrue(lock.acquire().done())
        N = 5
        history = []

        @gen.coroutine
        def f(idx):
            with (yield lock.acquire()):
                history.append(idx)

        futures = [f(i) for i in range(N)]
        self.assertFalse(any(future.done() for future in futures))
        lock.release()
        yield futures
        self.assertEqual(list(range(N)), history)

    @skipBefore35
    @gen_test
    def test_acquire_fifo_async_with(self):
        # Repeat the above test using `async with lock:`
        # instead of `with (yield lock.acquire()):`.
        lock = locks.Lock()
        self.assertTrue(lock.acquire().done())
        N = 5
        history = []

        namespace = exec_test(globals(), locals(), """
        async def f(idx):
            async with lock:
                history.append(idx)
        """)
        futures = [namespace['f'](i) for i in range(N)]
        lock.release()
        yield futures
        self.assertEqual(list(range(N)), history)

    @gen_test
    def test_acquire_timeout(self):
        lock = locks.Lock()
        lock.acquire()
        with self.assertRaises(gen.TimeoutError):
            yield lock.acquire(timeout=timedelta(seconds=0.01))

        # Still locked.
        self.assertFalse(lock.acquire().done())

    def test_multi_release(self):
        lock = locks.Lock()
        self.assertRaises(RuntimeError, lock.release)
        lock.acquire()
        lock.release()
        self.assertRaises(RuntimeError, lock.release)

    @gen_test
    def test_yield_lock(self):
        # Ensure we catch a "with (yield lock)", which should be
        # "with (yield lock.acquire())".
        with self.assertRaises(gen.BadYieldError):
            with (yield locks.Lock()):
                pass

    def test_context_manager_misuse(self):
        # Ensure we catch a "with lock", which should be
        # "with (yield lock.acquire())".
        with self.assertRaises(RuntimeError):
            with locks.Lock():
                pass


if __name__ == '__main__':
    unittest.main()
