Viewing file:  _discover.py (4.26 KB) -rw-r--r--
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import collections
import inspect
from automat import MethodicalMachine
from twisted.python.modules import PythonModule, getModule
def isOriginalLocation(attr):
"""
Attempt to discover if this appearance of a PythonAttribute
representing a class refers to the module where that class was
defined.
"""
sourceModule = inspect.getmodule(attr.load())
if sourceModule is None:
return False
currentModule = attr
while not isinstance(currentModule, PythonModule):
currentModule = currentModule.onObject
return currentModule.name == sourceModule.__name__
def findMachinesViaWrapper(within):
"""
Recursively yield L{MethodicalMachine}s and their FQPNs within a
L{PythonModule} or a L{twisted.python.modules.PythonAttribute}
wrapper object.
Note that L{PythonModule}s may refer to packages, as well.
The discovery heuristic considers L{MethodicalMachine} instances
that are module-level attributes or class-level attributes
accessible from module scope. Machines inside nested classes will
be discovered, but those returned from functions or methods will not be.
@type within: L{PythonModule} or L{twisted.python.modules.PythonAttribute}
@param within: Where to start the search.
@return: a generator which yields FQPN, L{MethodicalMachine} pairs.
"""
queue = collections.deque([within])
visited = set()
while queue:
attr = queue.pop()
value = attr.load()
if isinstance(value, MethodicalMachine) and value not in visited:
visited.add(value)
yield attr.name, value
elif (inspect.isclass(value) and isOriginalLocation(attr) and
value not in visited):
visited.add(value)
queue.extendleft(attr.iterAttributes())
elif isinstance(attr, PythonModule) and value not in visited:
visited.add(value)
queue.extendleft(attr.iterAttributes())
queue.extendleft(attr.iterModules())
class InvalidFQPN(Exception):
"""
The given FQPN was not a dot-separated list of Python objects.
"""
class NoModule(InvalidFQPN):
"""
A prefix of the FQPN was not an importable module or package.
"""
class NoObject(InvalidFQPN):
"""
A suffix of the FQPN was not an accessible object
"""
def wrapFQPN(fqpn):
"""
Given an FQPN, retrieve the object via the global Python module
namespace and wrap it with a L{PythonModule} or a
L{twisted.python.modules.PythonAttribute}.
"""
# largely cribbed from t.p.reflect.namedAny
if not fqpn:
raise InvalidFQPN("FQPN was empty")
components = collections.deque(fqpn.split('.'))
if '' in components:
raise InvalidFQPN(
"name must be a string giving a '.'-separated list of Python "
"identifiers, not %r" % (fqpn,))
component = components.popleft()
try:
module = getModule(component)
except KeyError:
raise NoModule(component)
# find the bottom-most module
while components:
component = components.popleft()
try:
module = module[component]
except KeyError:
components.appendleft(component)
break
else:
module.load()
else:
return module
# find the bottom-most attribute
attribute = module
for component in components:
try:
attribute = next(child for child in attribute.iterAttributes()
if child.name.rsplit('.', 1)[-1] == component)
except StopIteration:
raise NoObject('{}.{}'.format(attribute.name, component))
return attribute
def findMachines(fqpn):
"""
Recursively yield L{MethodicalMachine}s and their FQPNs in and
under the a Python object specified by an FQPN.
The discovery heuristic considers L{MethodicalMachine} instances
that are module-level attributes or class-level attributes
accessible from module scope. Machines inside nested classes will
be discovered, but those returned from functions or methods will not be.
@type within: an FQPN
@param within: Where to start the search.
@return: a generator which yields FQPN, L{MethodicalMachine} pairs.
"""
return findMachinesViaWrapper(wrapFQPN(fqpn))
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