def make_wrapped_function():
"""Wraps a function in three stack contexts, and returns
the function along with the deactivation functions.
"""
# Remove the test's stack context to make sure we can cover
# the case where the last context is deactivated.
with NullContext():
partial = functools.partial
with StackContext(partial(self.context, 'c0')) as c0:
with StackContext(partial(self.context, 'c1')) as c1:
with StackContext(partial(self.context, 'c2')) as c2:
return (wrap(check_contexts), [c0, c1, c2])
def test_pre_wrap(self):
# A pre-wrapped callback is run in the context in which it was
# wrapped, not when it was added to the IOLoop.
def f1():
self.assertIn('c1', self.active_contexts)
self.assertNotIn('c2', self.active_contexts)
self.stop()
with StackContext(functools.partial(self.context, 'c1')):
wrapped = wrap(f1)
with StackContext(functools.partial(self.context, 'c2')):
self.add_callback(wrapped)
self.wait()
def f():
self.callback = yield gen.Callback('a')
with StackContext(functools.partial(self.context, 'c1')):
# This yield is a problem: the generator will be suspended
# and the StackContext's __exit__ is not called yet, so
# the context will be left on _state.contexts for anything
# that runs before the yield resolves.
yield gen.Wait('a')
def test_pre_wrap_with_args(self):
# Same as test_pre_wrap, but the function takes arguments.
# Implementation note: The function must not be wrapped in a
# functools.partial until after it has been passed through
# stack_context.wrap
def f1(foo, bar):
self.assertIn('c1', self.active_contexts)
self.assertNotIn('c2', self.active_contexts)
self.stop((foo, bar))
with StackContext(functools.partial(self.context, 'c1')):
wrapped = wrap(f1)
with StackContext(functools.partial(self.context, 'c2')):
self.add_callback(wrapped, 1, bar=2)
result = self.wait()
self.assertEqual(result, (1, 2))
def test_run_with_stack_context(self):
@gen.coroutine
def f1():
self.assertEqual(self.active_contexts, ['c1'])
yield run_with_stack_context(
StackContext(functools.partial(self.context, 'c2')),
f2)
self.assertEqual(self.active_contexts, ['c1'])
@gen.coroutine
def f2():
self.assertEqual(self.active_contexts, ['c1', 'c2'])
yield gen.Task(self.io_loop.add_callback)
self.assertEqual(self.active_contexts, ['c1', 'c2'])
self.assertEqual(self.active_contexts, [])
yield run_with_stack_context(
StackContext(functools.partial(self.context, 'c1')),
f1)
self.assertEqual(self.active_contexts, [])
def test_exit_library_context(self):
def library_function(callback):
# capture the caller's context before introducing our own
callback = wrap(callback)
with StackContext(functools.partial(self.context, 'library')):
self.io_loop.add_callback(
functools.partial(library_inner_callback, callback))
def library_inner_callback(callback):
self.assertEqual(self.active_contexts[-2:],
['application', 'library'])
callback()
def final_callback():
# implementation detail: the full context stack at this point
# is ['application', 'library', 'application']. The 'library'
# context was not removed, but is no longer innermost so
# the application context takes precedence.
self.assertEqual(self.active_contexts[-1], 'application')
self.stop()
with StackContext(functools.partial(self.context, 'application')):
library_function(final_callback)
self.wait()
def library_function(callback):
# capture the caller's context before introducing our own
callback = wrap(callback)
with StackContext(functools.partial(self.context, 'library')):
self.io_loop.add_callback(
functools.partial(library_inner_callback, callback))
def f1():
self.assertEqual(self.active_contexts, ['c1'])
yield run_with_stack_context(
StackContext(functools.partial(self.context, 'c2')),
f2)
self.assertEqual(self.active_contexts, ['c1'])
def test_yield_outside_with(self):
# This pattern avoids the problem in the previous test.
cb = yield gen.Callback('k1')
with StackContext(functools.partial(self.context, 'c1')):
self.io_loop.add_callback(cb)
yield gen.Wait('k1')
def f1():
with NullContext():
wrapped = wrap(f2)
with StackContext(functools.partial(self.context, 'c2')):
wrapped()
def f3():
with StackContext(functools.partial(self.context, 'c3')) as c3:
deactivate_callbacks.append(c3)
self.io_loop.add_callback(f4)
def f2():
with StackContext(functools.partial(self.context, 'c2')) as c2:
deactivate_callbacks.append(c2)
self.io_loop.add_callback(f3)
def f1():
with StackContext(functools.partial(self.context, 'c1')) as c1:
deactivate_callbacks.append(c1)
self.io_loop.add_callback(f2)