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Your IP : 3.137.170.76
"""
Internal hook annotation, representation and calling machinery.
"""
from __future__ import annotations
import inspect
import sys
import warnings
from types import ModuleType
from typing import AbstractSet
from typing import Any
from typing import Callable
from typing import Generator
from typing import List
from typing import Mapping
from typing import Optional
from typing import overload
from typing import Sequence
from typing import Tuple
from typing import TYPE_CHECKING
from typing import TypeVar
from typing import Union
from ._result import _Result
if TYPE_CHECKING:
from typing_extensions import TypedDict
from typing_extensions import Final
_T = TypeVar("_T")
_F = TypeVar("_F", bound=Callable[..., object])
_Namespace = Union[ModuleType, type]
_Plugin = object
_HookExec = Callable[
[str, Sequence["HookImpl"], Mapping[str, object], bool],
Union[object, List[object]],
]
_HookImplFunction = Callable[..., Union[_T, Generator[None, _Result[_T], None]]]
if TYPE_CHECKING:
class _HookSpecOpts(TypedDict):
firstresult: bool
historic: bool
warn_on_impl: Warning | None
class _HookImplOpts(TypedDict):
wrapper: bool
hookwrapper: bool
optionalhook: bool
tryfirst: bool
trylast: bool
specname: str | None
class HookspecMarker:
"""Decorator for marking functions as hook specifications.
Instantiate it with a project_name to get a decorator.
Calling :meth:`PluginManager.add_hookspecs` later will discover all marked
functions if the :class:`PluginManager` uses the same project_name.
"""
__slots__ = ("project_name",)
def __init__(self, project_name: str) -> None:
self.project_name: Final = project_name
@overload
def __call__(
self,
function: _F,
firstresult: bool = False,
historic: bool = False,
warn_on_impl: Warning | None = None,
) -> _F:
...
@overload # noqa: F811
def __call__( # noqa: F811
self,
function: None = ...,
firstresult: bool = ...,
historic: bool = ...,
warn_on_impl: Warning | None = ...,
) -> Callable[[_F], _F]:
...
def __call__( # noqa: F811
self,
function: _F | None = None,
firstresult: bool = False,
historic: bool = False,
warn_on_impl: Warning | None = None,
) -> _F | Callable[[_F], _F]:
"""If passed a function, directly sets attributes on the function
which will make it discoverable to :meth:`PluginManager.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``, every call to the hook will be memorized
and replayed on plugins registered after the call was made.
"""
def setattr_hookspec_opts(func: _F) -> _F:
if historic and firstresult:
raise ValueError("cannot have a historic firstresult hook")
opts: _HookSpecOpts = {
"firstresult": firstresult,
"historic": historic,
"warn_on_impl": warn_on_impl,
}
setattr(func, self.project_name + "_spec", opts)
return func
if function is not None:
return setattr_hookspec_opts(function)
else:
return setattr_hookspec_opts
class HookimplMarker:
"""Decorator for marking functions as hook implementations.
Instantiate it with a ``project_name`` to get a decorator.
Calling :meth:`PluginManager.register` later will discover all marked
functions if the :class:`PluginManager` uses the same project_name.
"""
__slots__ = ("project_name",)
def __init__(self, project_name: str) -> None:
self.project_name: Final = project_name
@overload
def __call__(
self,
function: _F,
hookwrapper: bool = ...,
optionalhook: bool = ...,
tryfirst: bool = ...,
trylast: bool = ...,
specname: str | None = ...,
wrapper: bool = ...,
) -> _F:
...
@overload # noqa: F811
def __call__( # noqa: F811
self,
function: None = ...,
hookwrapper: bool = ...,
optionalhook: bool = ...,
tryfirst: bool = ...,
trylast: bool = ...,
specname: str | None = ...,
wrapper: bool = ...,
) -> Callable[[_F], _F]:
...
def __call__( # noqa: F811
self,
function: _F | None = None,
hookwrapper: bool = False,
optionalhook: bool = False,
tryfirst: bool = False,
trylast: bool = False,
specname: str | None = None,
wrapper: bool = False,
) -> _F | Callable[[_F], _F]:
"""If passed a function, directly sets attributes on the function
which will make it discoverable to :meth:`PluginManager.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 ``wrapper`` is ``True``("new-style hook wrapper"), the hook
implementation needs to execute exactly one ``yield``. The code before
the ``yield`` is run early before any non-hook-wrapper function is run.
The code after the ``yield`` is run after all non-hook-wrapper functions
have run. The ``yield`` receives the result value of the inner calls, or
raises the exception of inner calls (including earlier hook wrapper
calls). The return value of the function becomes the return value of the
hook, and a raised exception becomes the exception of the hook.
If ``hookwrapper`` is ``True`` ("old-style hook wrapper"), the hook
implementation needs to execute exactly one ``yield``. The code before
the ``yield`` is run early before any non-hook-wrapper function is run.
The code after the ``yield`` is run after all non-hook-wrapper function
have run The ``yield`` receives a :class:`_Result` object representing
the exception or result outcome of the inner calls (including earlier
hook wrapper calls). This option is mutually exclusive with ``wrapper``.
If ``specname`` is provided, it will be used instead of the function
name when matching this hook implementation to a hook specification
during registration.
.. versionadded:: 1.2.0
The ``wrapper`` parameter.
"""
def setattr_hookimpl_opts(func: _F) -> _F:
opts: _HookImplOpts = {
"wrapper": wrapper,
"hookwrapper": hookwrapper,
"optionalhook": optionalhook,
"tryfirst": tryfirst,
"trylast": trylast,
"specname": specname,
}
setattr(func, self.project_name + "_impl", opts)
return func
if function is None:
return setattr_hookimpl_opts
else:
return setattr_hookimpl_opts(function)
def normalize_hookimpl_opts(opts: _HookImplOpts) -> None:
opts.setdefault("tryfirst", False)
opts.setdefault("trylast", False)
opts.setdefault("wrapper", False)
opts.setdefault("hookwrapper", False)
opts.setdefault("optionalhook", False)
opts.setdefault("specname", None)
_PYPY = hasattr(sys, "pypy_version_info")
def varnames(func: object) -> tuple[tuple[str, ...], tuple[str, ...]]:
"""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.
"""
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.
sig = inspect.signature(
func.__func__ if inspect.ismethod(func) else func # type:ignore[arg-type]
)
except TypeError:
return (), ()
_valid_param_kinds = (
inspect.Parameter.POSITIONAL_ONLY,
inspect.Parameter.POSITIONAL_OR_KEYWORD,
)
_valid_params = {
name: param
for name, param in sig.parameters.items()
if param.kind in _valid_param_kinds
}
args = tuple(_valid_params)
defaults = (
tuple(
param.default
for param in _valid_params.values()
if param.default is not param.empty
)
or None
)
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
if not _PYPY:
implicit_names: tuple[str, ...] = ("self",)
else:
implicit_names = ("self", "obj")
if args:
qualname: str = getattr(func, "__qualname__", "")
if inspect.ismethod(func) or ("." in qualname and args[0] in implicit_names):
args = args[1:]
return args, kwargs
class _HookRelay:
"""Hook holder object for performing 1:N hook calls where N is the number
of registered plugins."""
__slots__ = ("__dict__",)
if TYPE_CHECKING:
def __getattr__(self, name: str) -> _HookCaller:
...
_CallHistory = List[Tuple[Mapping[str, object], Optional[Callable[[Any], None]]]]
class _HookCaller:
__slots__ = (
"name",
"spec",
"_hookexec",
"_hookimpls",
"_call_history",
)
def __init__(
self,
name: str,
hook_execute: _HookExec,
specmodule_or_class: _Namespace | None = None,
spec_opts: _HookSpecOpts | None = None,
) -> None:
self.name: Final = name
self._hookexec: Final = hook_execute
self._hookimpls: Final[list[HookImpl]] = []
self._call_history: _CallHistory | None = None
self.spec: HookSpec | None = 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) -> bool:
return self.spec is not None
def set_specification(
self,
specmodule_or_class: _Namespace,
spec_opts: _HookSpecOpts,
) -> None:
if self.spec is not None:
raise ValueError(
f"Hook {self.spec.name!r} is already registered "
f"within namespace {self.spec.namespace}"
)
self.spec = HookSpec(specmodule_or_class, self.name, spec_opts)
if spec_opts.get("historic"):
self._call_history = []
def is_historic(self) -> bool:
return self._call_history is not None
def _remove_plugin(self, plugin: _Plugin) -> None:
for i, method in enumerate(self._hookimpls):
if method.plugin == plugin:
del self._hookimpls[i]
return
raise ValueError(f"plugin {plugin!r} not found")
def get_hookimpls(self) -> list[HookImpl]:
return self._hookimpls.copy()
def _add_hookimpl(self, hookimpl: HookImpl) -> None:
"""Add an implementation to the callback chain."""
for i, method in enumerate(self._hookimpls):
if method.hookwrapper or method.wrapper:
splitpoint = i
break
else:
splitpoint = len(self._hookimpls)
if hookimpl.hookwrapper or hookimpl.wrapper:
start, end = splitpoint, len(self._hookimpls)
else:
start, end = 0, splitpoint
if hookimpl.trylast:
self._hookimpls.insert(start, hookimpl)
elif hookimpl.tryfirst:
self._hookimpls.insert(end, hookimpl)
else:
# find last non-tryfirst method
i = end - 1
while i >= start and self._hookimpls[i].tryfirst:
i -= 1
self._hookimpls.insert(i + 1, hookimpl)
def __repr__(self) -> str:
return f"<_HookCaller {self.name!r}>"
def _verify_all_args_are_provided(self, kwargs: Mapping[str, object]) -> None:
# This is written to avoid expensive operations when not needed.
if self.spec:
for argname in self.spec.argnames:
if argname not in kwargs:
notincall = ", ".join(
repr(argname)
for argname in self.spec.argnames
# Avoid self.spec.argnames - kwargs.keys() - doesn't preserve order.
if argname not in kwargs.keys()
)
warnings.warn(
"Argument(s) {} which are declared in the hookspec "
"cannot be found in this hook call".format(notincall),
stacklevel=2,
)
break
def __call__(self, **kwargs: object) -> Any:
assert (
not self.is_historic()
), "Cannot directly call a historic hook - use call_historic instead."
self._verify_all_args_are_provided(kwargs)
firstresult = self.spec.opts.get("firstresult", False) if self.spec else False
return self._hookexec(self.name, self._hookimpls, kwargs, firstresult)
def call_historic(
self,
result_callback: Callable[[Any], None] | None = None,
kwargs: Mapping[str, object] | None = None,
) -> None:
"""Call the hook with given ``kwargs`` for all registered plugins and
for all plugins which will be registered afterwards.
If ``result_callback`` is provided, it will be called for each
non-``None`` result obtained from a hook implementation.
"""
assert self._call_history is not None
kwargs = kwargs or {}
self._verify_all_args_are_provided(kwargs)
self._call_history.append((kwargs, result_callback))
# Historizing hooks don't return results.
# Remember firstresult isn't compatible with historic.
res = self._hookexec(self.name, self._hookimpls, kwargs, False)
if result_callback is None:
return
if isinstance(res, list):
for x in res:
result_callback(x)
def call_extra(
self, methods: Sequence[Callable[..., object]], kwargs: Mapping[str, object]
) -> Any:
"""Call the hook with some additional temporarily participating
methods using the specified ``kwargs`` as call parameters."""
assert (
not self.is_historic()
), "Cannot directly call a historic hook - use call_historic instead."
self._verify_all_args_are_provided(kwargs)
opts: _HookImplOpts = {
"wrapper": False,
"hookwrapper": False,
"optionalhook": False,
"trylast": False,
"tryfirst": False,
"specname": None,
}
hookimpls = self._hookimpls.copy()
for method in methods:
hookimpl = HookImpl(None, "<temp>", method, opts)
# Find last non-tryfirst nonwrapper method.
i = len(hookimpls) - 1
while (
i >= 0
and hookimpls[i].tryfirst
and not (hookimpls[i].hookwrapper or hookimpls[i].wrapper)
):
i -= 1
hookimpls.insert(i + 1, hookimpl)
firstresult = self.spec.opts.get("firstresult", False) if self.spec else False
return self._hookexec(self.name, hookimpls, kwargs, firstresult)
def _maybe_apply_history(self, method: HookImpl) -> None:
"""Apply call history to a new hookimpl if it is marked as historic."""
if self.is_historic():
assert self._call_history is not None
for kwargs, result_callback in self._call_history:
res = self._hookexec(self.name, [method], kwargs, False)
if res and result_callback is not None:
# XXX: remember firstresult isn't compat with historic
assert isinstance(res, list)
result_callback(res[0])
class _SubsetHookCaller(_HookCaller):
"""A proxy to another HookCaller which manages calls to all registered
plugins except the ones from remove_plugins."""
# This class is unusual: in inhertits from `_HookCaller` so all of
# the *code* runs in the class, but it delegates all underlying *data*
# to the original HookCaller.
# `subset_hook_caller` used to be implemented by creating a full-fledged
# HookCaller, copying all hookimpls from the original. This had problems
# with memory leaks (#346) and historic calls (#347), which make a proxy
# approach better.
# An alternative implementation is to use a `_getattr__`/`__getattribute__`
# proxy, however that adds more overhead and is more tricky to implement.
__slots__ = (
"_orig",
"_remove_plugins",
)
def __init__(self, orig: _HookCaller, remove_plugins: AbstractSet[_Plugin]) -> None:
self._orig = orig
self._remove_plugins = remove_plugins
self.name = orig.name # type: ignore[misc]
self._hookexec = orig._hookexec # type: ignore[misc]
@property # type: ignore[misc]
def _hookimpls(self) -> list[HookImpl]:
return [
impl
for impl in self._orig._hookimpls
if impl.plugin not in self._remove_plugins
]
@property
def spec(self) -> HookSpec | None: # type: ignore[override]
return self._orig.spec
@property
def _call_history(self) -> _CallHistory | None: # type: ignore[override]
return self._orig._call_history
def __repr__(self) -> str:
return f"<_SubsetHookCaller {self.name!r}>"
class HookImpl:
__slots__ = (
"function",
"argnames",
"kwargnames",
"plugin",
"opts",
"plugin_name",
"wrapper",
"hookwrapper",
"optionalhook",
"tryfirst",
"trylast",
)
def __init__(
self,
plugin: _Plugin,
plugin_name: str,
function: _HookImplFunction[object],
hook_impl_opts: _HookImplOpts,
) -> None:
self.function: Final = function
self.argnames, self.kwargnames = varnames(self.function)
self.plugin = plugin
self.opts = hook_impl_opts
self.plugin_name = plugin_name
self.wrapper = hook_impl_opts["wrapper"]
self.hookwrapper = hook_impl_opts["hookwrapper"]
self.optionalhook = hook_impl_opts["optionalhook"]
self.tryfirst = hook_impl_opts["tryfirst"]
self.trylast = hook_impl_opts["trylast"]
def __repr__(self) -> str:
return f"<HookImpl plugin_name={self.plugin_name!r}, plugin={self.plugin!r}>"
class HookSpec:
__slots__ = (
"namespace",
"function",
"name",
"argnames",
"kwargnames",
"opts",
"warn_on_impl",
)
def __init__(self, namespace: _Namespace, name: str, opts: _HookSpecOpts) -> None:
self.namespace = namespace
self.function: Callable[..., object] = getattr(namespace, name)
self.name = name
self.argnames, self.kwargnames = varnames(self.function)
self.opts = opts
self.warn_on_impl = opts.get("warn_on_impl")