# Copyright (c) 2013 Potential Ventures Ltd
# Copyright (c) 2013 SolarFlare Communications Inc
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#
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# names of its contributors may be used to endorse or promote products
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#
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import sys
import time
import logging
import functools
import inspect
import os
import warnings
import cocotb
from cocotb.log import SimLog
from cocotb.result import ReturnValue
from cocotb.utils import get_sim_time, lazy_property, remove_traceback_frames, extract_coro_stack
from cocotb import outcomes
# Sadly the Python standard logging module is very slow so it's better not to
# make any calls by testing a boolean flag first
if "COCOTB_SCHEDULER_DEBUG" in os.environ:
_debug = True
else:
_debug = False
def public(f):
"""Use a decorator to avoid retyping function/class names.
* Based on an idea by Duncan Booth:
http://groups.google.com/group/comp.lang.python/msg/11cbb03e09611b8a
* Improved via a suggestion by Dave Angel:
http://groups.google.com/group/comp.lang.python/msg/3d400fb22d8a42e1
"""
all = sys.modules[f.__module__].__dict__.setdefault('__all__', [])
if f.__name__ not in all: # Prevent duplicates if run from an IDE.
all.append(f.__name__)
return f
public(public) # Emulate decorating ourself
@public
class CoroutineComplete(Exception):
"""To ensure that a coroutine has completed before we fire any triggers
that are blocked waiting for the coroutine to end, we create a sub-class
exception that the scheduler catches and the callbacks are attached
here.
"""
def __init__(self, text=""):
Exception.__init__(self, text)
class RunningTask:
"""Per instance wrapper around a running generator.
Provides the following:
task.join() creates a Trigger that will fire when this coroutine
completes.
task.kill() will destroy a coroutine instance (and cause any Join
triggers to fire.
"""
_id_count = 0 # used by the scheduler for debug
def __init__(self, inst):
if inspect.iscoroutine(inst):
self._natively_awaitable = True
elif inspect.isgenerator(inst):
self._natively_awaitable = False
elif inspect.iscoroutinefunction(inst):
raise TypeError(
"Coroutine function {} should be called prior to being "
"scheduled."
.format(inst))
elif sys.version_info >= (3, 6) and inspect.isasyncgen(inst):
raise TypeError(
"{} is an async generator, not a coroutine. "
"You likely used the yield keyword instead of await.".format(
inst.__qualname__))
else:
raise TypeError(
"%s isn't a valid coroutine! Did you forget to use the yield keyword?" % inst)
self._coro = inst
self._started = False
self._callbacks = []
self._outcome = None
self._trigger = None
self._task_id = self._id_count
RunningTask._id_count += 1
self.__name__ = "Task %d" % self._task_id
self.__qualname__ = self.__name__
@lazy_property
def log(self):
# Creating a logger is expensive, only do it if we actually plan to
# log anything
return SimLog("cocotb.coroutine.%s" % self.__qualname__, id(self))
@property
def retval(self):
if self._outcome is None:
raise RuntimeError("coroutine is not complete")
return self._outcome.get()
@property
def _finished(self):
return self._outcome is not None
def __iter__(self):
return self
def __str__(self):
return "<{}>".format(self.__name__)
def _get_coro_stack(self):
"""Get the coroutine callstack of this Task."""
coro_stack = extract_coro_stack(self._coro)
# Remove Trigger.__await__() from the stack, as it's not really useful
if self._natively_awaitable and len(coro_stack):
if coro_stack[-1].name == '__await__':
coro_stack.pop()
return coro_stack
def __repr__(self):
coro_stack = self._get_coro_stack()
if cocotb.scheduler._current_task is self:
fmt = "<{name} running coro={coro}()>"
elif self._finished:
fmt = "<{name} finished coro={coro}() outcome={outcome}>"
elif self._trigger is not None:
fmt = "<{name} pending coro={coro}() trigger={trigger}>"
elif not self._started:
fmt = "<{name} created coro={coro}()>"
else:
fmt = "<{name} adding coro={coro}()>"
try:
coro_name = coro_stack[-1].name
# coro_stack may be empty if:
# - exhausted generator
# - finished coroutine
except IndexError:
coro_name = self._coro.__name__
repr_string = fmt.format(
name=self.__name__,
coro=coro_name,
trigger=self._trigger,
outcome=self._outcome
)
return repr_string
def _advance(self, outcome):
"""Advance to the next yield in this coroutine.
Args:
outcome: The :any:`outcomes.Outcome` object to resume with.
Returns:
The object yielded from the coroutine
Raises:
CoroutineComplete: If the coroutine returns or throws an error, self._outcome is set, and
:exc:`CoroutineComplete` is thrown.
"""
try:
self._started = True
return outcome.send(self._coro)
except ReturnValue as e:
self._outcome = outcomes.Value(e.retval)
raise CoroutineComplete()
except StopIteration as e:
self._outcome = outcomes.Value(e.value)
raise CoroutineComplete()
except BaseException as e:
self._outcome = outcomes.Error(remove_traceback_frames(e, ['_advance', 'send']))
raise CoroutineComplete()
def send(self, value):
return self._coro.send(value)
def throw(self, exc):
return self._coro.throw(exc)
def close(self):
return self._coro.close()
def kill(self):
"""Kill a coroutine."""
if self._outcome is not None:
# already finished, nothing to kill
return
if _debug:
self.log.debug("kill() called on coroutine")
# todo: probably better to throw an exception for anyone waiting on the coroutine
self._outcome = outcomes.Value(None)
cocotb.scheduler._unschedule(self)
def join(self):
"""Return a trigger that will fire when the wrapped coroutine exits."""
return cocotb.triggers.Join(self)
def has_started(self):
return self._started
def __bool__(self):
"""Provide boolean testing
if the coroutine has finished return false
otherwise return true"""
return not self._finished
def __await__(self):
# It's tempting to use `return (yield from self._coro)` here,
# which bypasses the scheduler. Unfortunately, this means that
# we can't keep track of the result or state of the coroutine,
# things which we expose in our public API. If you want the
# efficiency of bypassing the scheduler, remove the `@coroutine`
# decorator from your `async` functions.
# Hand the coroutine back to the scheduler trampoline.
return (yield self)
class RunningCoroutine(RunningTask):
"""
The result of calling a :any:`cocotb.coroutine` decorated coroutine.
All this class does is provide some extra attributes.
"""
def __init__(self, inst, parent):
RunningTask.__init__(self, inst)
self._parent = parent
self.__doc__ = parent._func.__doc__
self.module = parent._func.__module__
self.funcname = parent._func.__name__
class RunningTest(RunningCoroutine):
"""Add some useful Test functionality to a RunningCoroutine."""
class ErrorLogHandler(logging.Handler):
def __init__(self, fn):
self.fn = fn
logging.Handler.__init__(self, level=logging.DEBUG)
def handle(self, record):
# For historical reasons, only logs sent directly to the `cocotb`
# logger are recorded - logs to `cocotb.scheduler` for instance
# are not recorded. Changing this behavior may have significant
# memory usage implications, so should not be done without some
# thought.
if record.name == 'cocotb':
self.fn(self.format(record))
def __init__(self, inst, parent):
self.error_messages = []
RunningCoroutine.__init__(self, inst, parent)
self.log = SimLog("cocotb.test.%s" % inst.__qualname__, id(self))
self.started = False
self.start_time = 0
self.start_sim_time = 0
self.expect_fail = parent.expect_fail
self.expect_error = parent.expect_error
self.skip = parent.skip
self.stage = parent.stage
self.__name__ = "Test %s" % inst.__name__
self.__qualname__ = "Test %s" % inst.__qualname__
# make sure not to create a circular reference here
self.handler = RunningTest.ErrorLogHandler(self.error_messages.append)
def __str__(self):
return "<{}>".format(self.__name__)
def _advance(self, outcome):
if not self.started:
self.log.info("Starting test: \"%s\"\nDescription: %s" %
(self.funcname, self.__doc__))
self.start_time = time.time()
self.start_sim_time = get_sim_time('ns')
self.started = True
return super(RunningTest, self)._advance(outcome)
# like RunningTask.kill(), but with a way to inject a failure
def abort(self, exc):
"""Force this test to end early, without executing any cleanup.
This happens when a background task fails, and is consistent with
how the behavior has always been. In future, we may want to behave
more gracefully to allow the test body to clean up.
`exc` is the exception that the test should report as its reason for
aborting.
"""
if self._outcome is not None:
# imported here to avoid circular imports
from cocotb.scheduler import InternalError
raise InternalError("Outcome already has a value, but is being set again.")
outcome = outcomes.Error(exc)
if _debug:
self.log.debug("outcome forced to {}".format(outcome))
self._outcome = outcome
cocotb.scheduler._unschedule(self)
def sort_name(self):
if self.stage is None:
return "%s.%s" % (self.module, self.funcname)
else:
return "%s.%d.%s" % (self.module, self.stage, self.funcname)
[docs]class coroutine:
"""Decorator class that allows us to provide common coroutine mechanisms:
``log`` methods will log to ``cocotb.coroutine.name``.
:meth:`~cocotb.decorators.RunningTask.join` method returns an event which will fire when the coroutine exits.
Used as ``@cocotb.coroutine``.
"""
def __init__(self, func):
self._func = func
functools.update_wrapper(self, func)
@lazy_property
def log(self):
return SimLog("cocotb.coroutine.%s" % self._func.__qualname__, id(self))
def __call__(self, *args, **kwargs):
return RunningCoroutine(self._func(*args, **kwargs), self)
def __get__(self, obj, owner=None):
"""Permit the decorator to be used on class methods
and standalone functions"""
return type(self)(self._func.__get__(obj, owner))
def __iter__(self):
return self
def __str__(self):
return str(self._func.__qualname__)
[docs]@public
class function:
"""Decorator class that allows a function to block.
This allows a coroutine that consumes simulation time
to be called by a thread started with :class:`cocotb.external`;
in other words, to internally block while externally
appear to yield.
"""
def __init__(self, func):
self._coro = cocotb.coroutine(func)
@lazy_property
def log(self):
return SimLog("cocotb.function.%s" % self._coro.__qualname__, id(self))
def __call__(self, *args, **kwargs):
return cocotb.scheduler._queue_function(self._coro(*args, **kwargs))
def __get__(self, obj, owner=None):
"""Permit the decorator to be used on class methods
and standalone functions"""
return type(self)(self._coro._func.__get__(obj, owner))
[docs]@public
class external:
"""Decorator to apply to an external function to enable calling from cocotb.
This turns a normal function that isn't a coroutine into a blocking coroutine.
Currently, this creates a new execution thread for each function that is
called.
Scope for this to be streamlined to a queue in future.
"""
def __init__(self, func):
self._func = func
self._log = SimLog("cocotb.external.%s" % self._func.__qualname__, id(self))
def __call__(self, *args, **kwargs):
return cocotb.scheduler._run_in_executor(self._func, *args, **kwargs)
def __get__(self, obj, owner=None):
"""Permit the decorator to be used on class methods
and standalone functions"""
return type(self)(self._func.__get__(obj, owner))
class _decorator_helper(type):
"""
Metaclass that allows a type to be constructed using decorator syntax,
passing the decorated function as the first argument.
So:
@MyClass(construction, args='go here')
def this_is_passed_as_f(...):
pass
ends up calling
MyClass.__init__(this_is_passed_as_f, construction, args='go here')
"""
def __call__(cls, *args, **kwargs):
def decorator(f):
# fall back to the normal way of constructing an object, now that
# we have all the arguments
return type.__call__(cls, f, *args, **kwargs)
return decorator
[docs]@public
class hook(coroutine, metaclass=_decorator_helper):
r"""
Decorator to mark a function as a hook for cocotb.
Used as ``@cocotb.hook()``.
All hooks are run at the beginning of a cocotb test suite, prior to any
test code being run.
.. deprecated:: 1.5
Hooks are deprecated.
Their functionality can be replaced with module-level Python code,
higher-priority tests using the ``stage`` argument to :func:`cocotb.test`\ s,
or custom decorators which perform work before and after the tests
they decorate.
"""
def __init__(self, f):
super(hook, self).__init__(f)
warnings.warn(
"Hooks have been deprecated. See the documentation for suggestions on alternatives.",
DeprecationWarning, stacklevel=2)
self.im_hook = True
self.name = self._func.__name__
[docs]@public
class test(coroutine, metaclass=_decorator_helper):
"""Decorator to mark a function as a test.
All tests are coroutines. The test decorator provides
some common reporting etc., a test timeout and allows
us to mark tests as expected failures.
Tests are evaluated in the order they are defined in a test module.
Used as ``@cocotb.test(...)``.
Args:
timeout_time (numbers.Real or decimal.Decimal, optional):
Simulation time duration before timeout occurs.
.. versionadded:: 1.3
.. note::
Test timeout is intended for protection against deadlock.
Users should use :class:`~cocotb.triggers.with_timeout` if they require a
more general-purpose timeout mechanism.
timeout_unit (str, optional):
Units of timeout_time, accepts any units that :class:`~cocotb.triggers.Timer` does.
.. versionadded:: 1.3
.. deprecated:: 1.5
Using None as the the *timeout_unit* argument is deprecated, use ``'step'`` instead.
expect_fail (bool, optional):
Don't mark the result as a failure if the test fails.
expect_error (exception type or tuple of exception types, optional):
Mark the result as a pass only if one of the exception types is raised in the test.
This is primarily for cocotb internal regression use for when a simulator error is expected.
Users are encouraged to use the following idiom instead::
@cocotb.test()
async def my_test(dut):
try:
await thing_that_should_fail()
except ExceptionIExpect:
pass
else:
assert False, "Exception did not occur"
.. versionchanged:: 1.3
Specific exception types can be expected
.. deprecated:: 1.5
Passing a :class:`bool` value is now deprecated.
Pass a specific :class:`Exception` or a tuple of Exceptions instead.
skip (bool, optional):
Don't execute this test as part of the regression. Test can still be run
manually by setting :make:var:`TESTCASE`.
stage (int, optional)
Order tests logically into stages, where multiple tests can share a stage.
"""
_id_count = 0 # used by the RegressionManager to sort tests in definition order
def __init__(self, f, timeout_time=None, timeout_unit="step",
expect_fail=False, expect_error=(),
skip=False, stage=None):
if timeout_unit is None:
warnings.warn(
'Using timeout_unit=None is deprecated, use timeout_unit="step" instead.',
DeprecationWarning, stacklevel=2)
timeout_unit="step" # don't propagate deprecated value
self._id = self._id_count
type(self)._id_count += 1
if timeout_time is not None:
co = coroutine(f)
@functools.wraps(f)
async def f(*args, **kwargs):
running_co = co(*args, **kwargs)
try:
res = await cocotb.triggers.with_timeout(running_co, self.timeout_time, self.timeout_unit)
except cocotb.result.SimTimeoutError:
running_co.kill()
raise
else:
return res
super(test, self).__init__(f)
self.timeout_time = timeout_time
self.timeout_unit = timeout_unit
self.expect_fail = expect_fail
if isinstance(expect_error, bool):
warnings.warn(
"Passing bool values to `except_error` option of `cocotb.test` is deprecated. "
"Pass a specific Exception type instead",
DeprecationWarning, stacklevel=2)
if expect_error is True:
expect_error = (Exception,)
elif expect_error is False:
expect_error = ()
self.expect_error = expect_error
self.skip = skip
self.stage = stage
self.im_test = True # For auto-regressions
self.name = self._func.__name__
def __call__(self, *args, **kwargs):
return RunningTest(self._func(*args, **kwargs), self)