Current File : //lib/python3/dist-packages/pluggy/hooks.py
"""
Internal hook annotation, representation and calling machinery.
"""
import inspect
import sys
import warnings
from .callers import _legacymulticall, _multicall
class HookspecMarker(object):
""" Decorator helper class for marking functions as hook specifications.
You can instantiate it with a project_name to get a decorator.
Calling PluginManager.add_hookspecs later will discover all marked functions
if the PluginManager uses the same project_name.
"""
def __init__(self, project_name):
self.project_name = project_name
def __call__(
self, function=None, firstresult=False, historic=False, warn_on_impl=None
):
""" if passed a function, directly sets attributes on the function
which will make it discoverable to add_hookspecs(). If passed no
function, returns a decorator which can be applied to a function
later using the attributes supplied.
If firstresult is True the 1:N hook call (N being the number of registered
hook implementation functions) will stop at I<=N when the I'th function
returns a non-None result.
If historic is True calls to a hook will be memorized and replayed
on later registered plugins.
"""
def setattr_hookspec_opts(func):
if historic and firstresult:
raise ValueError("cannot have a historic firstresult hook")
setattr(
func,
self.project_name + "_spec",
dict(
firstresult=firstresult,
historic=historic,
warn_on_impl=warn_on_impl,
),
)
return func
if function is not None:
return setattr_hookspec_opts(function)
else:
return setattr_hookspec_opts
class HookimplMarker(object):
""" Decorator helper class for marking functions as hook implementations.
You can instantiate with a project_name to get a decorator.
Calling PluginManager.register later will discover all marked functions
if the PluginManager uses the same project_name.
"""
def __init__(self, project_name):
self.project_name = project_name
def __call__(
self,
function=None,
hookwrapper=False,
optionalhook=False,
tryfirst=False,
trylast=False,
):
""" if passed a function, directly sets attributes on the function
which will make it discoverable to register(). If passed no function,
returns a decorator which can be applied to a function later using
the attributes supplied.
If optionalhook is True a missing matching hook specification will not result
in an error (by default it is an error if no matching spec is found).
If tryfirst is True this hook implementation will run as early as possible
in the chain of N hook implementations for a specification.
If trylast is True this hook implementation will run as late as possible
in the chain of N hook implementations.
If hookwrapper is True the hook implementations needs to execute exactly
one "yield". The code before the yield is run early before any non-hookwrapper
function is run. The code after the yield is run after all non-hookwrapper
function have run. The yield receives a ``_Result`` object representing
the exception or result outcome of the inner calls (including other hookwrapper
calls).
"""
def setattr_hookimpl_opts(func):
setattr(
func,
self.project_name + "_impl",
dict(
hookwrapper=hookwrapper,
optionalhook=optionalhook,
tryfirst=tryfirst,
trylast=trylast,
),
)
return func
if function is None:
return setattr_hookimpl_opts
else:
return setattr_hookimpl_opts(function)
def normalize_hookimpl_opts(opts):
opts.setdefault("tryfirst", False)
opts.setdefault("trylast", False)
opts.setdefault("hookwrapper", False)
opts.setdefault("optionalhook", False)
if hasattr(inspect, "getfullargspec"):
def _getargspec(func):
return inspect.getfullargspec(func)
else:
def _getargspec(func):
return inspect.getargspec(func)
_PYPY3 = hasattr(sys, "pypy_version_info") and sys.version_info.major == 3
def varnames(func):
"""Return tuple of positional and keywrord argument names for a function,
method, class or callable.
In case of a class, its ``__init__`` method is considered.
For methods the ``self`` parameter is not included.
"""
cache = getattr(func, "__dict__", {})
try:
return cache["_varnames"]
except KeyError:
pass
if inspect.isclass(func):
try:
func = func.__init__
except AttributeError:
return (), ()
elif not inspect.isroutine(func): # callable object?
try:
func = getattr(func, "__call__", func)
except Exception:
return (), ()
try: # func MUST be a function or method here or we won't parse any args
spec = _getargspec(func)
except TypeError:
return (), ()
args, defaults = tuple(spec.args), spec.defaults
if defaults:
index = -len(defaults)
args, kwargs = args[:index], tuple(args[index:])
else:
kwargs = ()
# strip any implicit instance arg
# pypy3 uses "obj" instead of "self" for default dunder methods
implicit_names = ("self",) if not _PYPY3 else ("self", "obj")
if args:
if inspect.ismethod(func) or (
"." in getattr(func, "__qualname__", ()) and args[0] in implicit_names
):
args = args[1:]
try:
cache["_varnames"] = args, kwargs
except TypeError:
pass
return args, kwargs
class _HookRelay(object):
""" hook holder object for performing 1:N hook calls where N is the number
of registered plugins.
"""
class _HookCaller(object):
def __init__(self, name, hook_execute, specmodule_or_class=None, spec_opts=None):
self.name = name
self._wrappers = []
self._nonwrappers = []
self._hookexec = hook_execute
self.argnames = None
self.kwargnames = None
self.multicall = _multicall
self.spec = None
if specmodule_or_class is not None:
assert spec_opts is not None
self.set_specification(specmodule_or_class, spec_opts)
def has_spec(self):
return self.spec is not None
def set_specification(self, specmodule_or_class, spec_opts):
assert not self.has_spec()
self.spec = HookSpec(specmodule_or_class, self.name, spec_opts)
if spec_opts.get("historic"):
self._call_history = []
def is_historic(self):
return hasattr(self, "_call_history")
def _remove_plugin(self, plugin):
def remove(wrappers):
for i, method in enumerate(wrappers):
if method.plugin == plugin:
del wrappers[i]
return True
if remove(self._wrappers) is None:
if remove(self._nonwrappers) is None:
raise ValueError("plugin %r not found" % (plugin,))
def get_hookimpls(self):
# Order is important for _hookexec
return self._nonwrappers + self._wrappers
def _add_hookimpl(self, hookimpl):
"""Add an implementation to the callback chain.
"""
if hookimpl.hookwrapper:
methods = self._wrappers
else:
methods = self._nonwrappers
if hookimpl.trylast:
methods.insert(0, hookimpl)
elif hookimpl.tryfirst:
methods.append(hookimpl)
else:
# find last non-tryfirst method
i = len(methods) - 1
while i >= 0 and methods[i].tryfirst:
i -= 1
methods.insert(i + 1, hookimpl)
if "__multicall__" in hookimpl.argnames:
warnings.warn(
"Support for __multicall__ is now deprecated and will be"
"removed in an upcoming release.",
DeprecationWarning,
)
self.multicall = _legacymulticall
def __repr__(self):
return "<_HookCaller %r>" % (self.name,)
def __call__(self, *args, **kwargs):
if args:
raise TypeError("hook calling supports only keyword arguments")
assert not self.is_historic()
if self.spec and self.spec.argnames:
notincall = (
set(self.spec.argnames) - set(["__multicall__"]) - set(kwargs.keys())
)
if notincall:
warnings.warn(
"Argument(s) {} which are declared in the hookspec "
"can not be found in this hook call".format(tuple(notincall)),
stacklevel=2,
)
return self._hookexec(self, self.get_hookimpls(), kwargs)
def call_historic(self, result_callback=None, kwargs=None, proc=None):
"""Call the hook with given ``kwargs`` for all registered plugins and
for all plugins which will be registered afterwards.
If ``result_callback`` is not ``None`` it will be called for for each
non-None result obtained from a hook implementation.
.. note::
The ``proc`` argument is now deprecated.
"""
if proc is not None:
warnings.warn(
"Support for `proc` argument is now deprecated and will be"
"removed in an upcoming release.",
DeprecationWarning,
)
result_callback = proc
self._call_history.append((kwargs or {}, result_callback))
# historizing hooks don't return results
res = self._hookexec(self, self.get_hookimpls(), kwargs)
if result_callback is None:
return
# XXX: remember firstresult isn't compat with historic
for x in res or []:
result_callback(x)
def call_extra(self, methods, kwargs):
""" Call the hook with some additional temporarily participating
methods using the specified kwargs as call parameters. """
old = list(self._nonwrappers), list(self._wrappers)
for method in methods:
opts = dict(hookwrapper=False, trylast=False, tryfirst=False)
hookimpl = HookImpl(None, "<temp>", method, opts)
self._add_hookimpl(hookimpl)
try:
return self(**kwargs)
finally:
self._nonwrappers, self._wrappers = old
def _maybe_apply_history(self, method):
"""Apply call history to a new hookimpl if it is marked as historic.
"""
if self.is_historic():
for kwargs, result_callback in self._call_history:
res = self._hookexec(self, [method], kwargs)
if res and result_callback is not None:
result_callback(res[0])
class HookImpl(object):
def __init__(self, plugin, plugin_name, function, hook_impl_opts):
self.function = function
self.argnames, self.kwargnames = varnames(self.function)
self.plugin = plugin
self.opts = hook_impl_opts
self.plugin_name = plugin_name
self.__dict__.update(hook_impl_opts)
def __repr__(self):
return "<HookImpl plugin_name=%r, plugin=%r>" % (self.plugin_name, self.plugin)
class HookSpec(object):
def __init__(self, namespace, name, opts):
self.namespace = namespace
self.function = function = getattr(namespace, name)
self.name = name
self.argnames, self.kwargnames = varnames(function)
self.opts = opts
self.argnames = ["__multicall__"] + list(self.argnames)
self.warn_on_impl = opts.get("warn_on_impl")
Mini Shell