diff options
Diffstat (limited to 'venv/lib/python3.8/site-packages/werkzeug/local.py')
| -rw-r--r-- | venv/lib/python3.8/site-packages/werkzeug/local.py | 653 |
1 files changed, 653 insertions, 0 deletions
diff --git a/venv/lib/python3.8/site-packages/werkzeug/local.py b/venv/lib/python3.8/site-packages/werkzeug/local.py new file mode 100644 index 0000000..302589b --- /dev/null +++ b/venv/lib/python3.8/site-packages/werkzeug/local.py @@ -0,0 +1,653 @@ +from __future__ import annotations + +import copy +import math +import operator +import typing as t +from contextvars import ContextVar +from functools import partial +from functools import update_wrapper +from operator import attrgetter + +from .wsgi import ClosingIterator + +if t.TYPE_CHECKING: + from _typeshed.wsgi import StartResponse + from _typeshed.wsgi import WSGIApplication + from _typeshed.wsgi import WSGIEnvironment + +T = t.TypeVar("T") +F = t.TypeVar("F", bound=t.Callable[..., t.Any]) + + +def release_local(local: Local | LocalStack[t.Any]) -> None: + """Release the data for the current context in a :class:`Local` or + :class:`LocalStack` without using a :class:`LocalManager`. + + This should not be needed for modern use cases, and may be removed + in the future. + + .. versionadded:: 0.6.1 + """ + local.__release_local__() + + +class Local: + """Create a namespace of context-local data. This wraps a + :class:`ContextVar` containing a :class:`dict` value. + + This may incur a performance penalty compared to using individual + context vars, as it has to copy data to avoid mutating the dict + between nested contexts. + + :param context_var: The :class:`~contextvars.ContextVar` to use as + storage for this local. If not given, one will be created. + Context vars not created at the global scope may interfere with + garbage collection. + + .. versionchanged:: 2.0 + Uses ``ContextVar`` instead of a custom storage implementation. + """ + + __slots__ = ("__storage",) + + def __init__(self, context_var: ContextVar[dict[str, t.Any]] | None = None) -> None: + if context_var is None: + # A ContextVar not created at global scope interferes with + # Python's garbage collection. However, a local only makes + # sense defined at the global scope as well, in which case + # the GC issue doesn't seem relevant. + context_var = ContextVar(f"werkzeug.Local<{id(self)}>.storage") + + object.__setattr__(self, "_Local__storage", context_var) + + def __iter__(self) -> t.Iterator[tuple[str, t.Any]]: + return iter(self.__storage.get({}).items()) + + def __call__( + self, name: str, *, unbound_message: str | None = None + ) -> LocalProxy[t.Any]: + """Create a :class:`LocalProxy` that access an attribute on this + local namespace. + + :param name: Proxy this attribute. + :param unbound_message: The error message that the proxy will + show if the attribute isn't set. + """ + return LocalProxy(self, name, unbound_message=unbound_message) + + def __release_local__(self) -> None: + self.__storage.set({}) + + def __getattr__(self, name: str) -> t.Any: + values = self.__storage.get({}) + + if name in values: + return values[name] + + raise AttributeError(name) + + def __setattr__(self, name: str, value: t.Any) -> None: + values = self.__storage.get({}).copy() + values[name] = value + self.__storage.set(values) + + def __delattr__(self, name: str) -> None: + values = self.__storage.get({}) + + if name in values: + values = values.copy() + del values[name] + self.__storage.set(values) + else: + raise AttributeError(name) + + +class LocalStack(t.Generic[T]): + """Create a stack of context-local data. This wraps a + :class:`ContextVar` containing a :class:`list` value. + + This may incur a performance penalty compared to using individual + context vars, as it has to copy data to avoid mutating the list + between nested contexts. + + :param context_var: The :class:`~contextvars.ContextVar` to use as + storage for this local. If not given, one will be created. + Context vars not created at the global scope may interfere with + garbage collection. + + .. versionchanged:: 2.0 + Uses ``ContextVar`` instead of a custom storage implementation. + + .. versionadded:: 0.6.1 + """ + + __slots__ = ("_storage",) + + def __init__(self, context_var: ContextVar[list[T]] | None = None) -> None: + if context_var is None: + # A ContextVar not created at global scope interferes with + # Python's garbage collection. However, a local only makes + # sense defined at the global scope as well, in which case + # the GC issue doesn't seem relevant. + context_var = ContextVar(f"werkzeug.LocalStack<{id(self)}>.storage") + + self._storage = context_var + + def __release_local__(self) -> None: + self._storage.set([]) + + def push(self, obj: T) -> list[T]: + """Add a new item to the top of the stack.""" + stack = self._storage.get([]).copy() + stack.append(obj) + self._storage.set(stack) + return stack + + def pop(self) -> T | None: + """Remove the top item from the stack and return it. If the + stack is empty, return ``None``. + """ + stack = self._storage.get([]) + + if len(stack) == 0: + return None + + rv = stack[-1] + self._storage.set(stack[:-1]) + return rv + + @property + def top(self) -> T | None: + """The topmost item on the stack. If the stack is empty, + `None` is returned. + """ + stack = self._storage.get([]) + + if len(stack) == 0: + return None + + return stack[-1] + + def __call__( + self, name: str | None = None, *, unbound_message: str | None = None + ) -> LocalProxy[t.Any]: + """Create a :class:`LocalProxy` that accesses the top of this + local stack. + + :param name: If given, the proxy access this attribute of the + top item, rather than the item itself. + :param unbound_message: The error message that the proxy will + show if the stack is empty. + """ + return LocalProxy(self, name, unbound_message=unbound_message) + + +class LocalManager: + """Manage releasing the data for the current context in one or more + :class:`Local` and :class:`LocalStack` objects. + + This should not be needed for modern use cases, and may be removed + in the future. + + :param locals: A local or list of locals to manage. + + .. versionchanged:: 2.1 + The ``ident_func`` was removed. + + .. versionchanged:: 0.7 + The ``ident_func`` parameter was added. + + .. versionchanged:: 0.6.1 + The :func:`release_local` function can be used instead of a + manager. + """ + + __slots__ = ("locals",) + + def __init__( + self, + locals: None + | (Local | LocalStack[t.Any] | t.Iterable[Local | LocalStack[t.Any]]) = None, + ) -> None: + if locals is None: + self.locals = [] + elif isinstance(locals, Local): + self.locals = [locals] + else: + self.locals = list(locals) # type: ignore[arg-type] + + def cleanup(self) -> None: + """Release the data in the locals for this context. Call this at + the end of each request or use :meth:`make_middleware`. + """ + for local in self.locals: + release_local(local) + + def make_middleware(self, app: WSGIApplication) -> WSGIApplication: + """Wrap a WSGI application so that local data is released + automatically after the response has been sent for a request. + """ + + def application( + environ: WSGIEnvironment, start_response: StartResponse + ) -> t.Iterable[bytes]: + return ClosingIterator(app(environ, start_response), self.cleanup) + + return application + + def middleware(self, func: WSGIApplication) -> WSGIApplication: + """Like :meth:`make_middleware` but used as a decorator on the + WSGI application function. + + .. code-block:: python + + @manager.middleware + def application(environ, start_response): + ... + """ + return update_wrapper(self.make_middleware(func), func) + + def __repr__(self) -> str: + return f"<{type(self).__name__} storages: {len(self.locals)}>" + + +class _ProxyLookup: + """Descriptor that handles proxied attribute lookup for + :class:`LocalProxy`. + + :param f: The built-in function this attribute is accessed through. + Instead of looking up the special method, the function call + is redone on the object. + :param fallback: Return this function if the proxy is unbound + instead of raising a :exc:`RuntimeError`. + :param is_attr: This proxied name is an attribute, not a function. + Call the fallback immediately to get the value. + :param class_value: Value to return when accessed from the + ``LocalProxy`` class directly. Used for ``__doc__`` so building + docs still works. + """ + + __slots__ = ("bind_f", "fallback", "is_attr", "class_value", "name") + + def __init__( + self, + f: t.Callable[..., t.Any] | None = None, + fallback: t.Callable[[LocalProxy[t.Any]], t.Any] | None = None, + class_value: t.Any | None = None, + is_attr: bool = False, + ) -> None: + bind_f: t.Callable[[LocalProxy[t.Any], t.Any], t.Callable[..., t.Any]] | None + + if hasattr(f, "__get__"): + # A Python function, can be turned into a bound method. + + def bind_f( + instance: LocalProxy[t.Any], obj: t.Any + ) -> t.Callable[..., t.Any]: + return f.__get__(obj, type(obj)) # type: ignore + + elif f is not None: + # A C function, use partial to bind the first argument. + + def bind_f( + instance: LocalProxy[t.Any], obj: t.Any + ) -> t.Callable[..., t.Any]: + return partial(f, obj) + + else: + # Use getattr, which will produce a bound method. + bind_f = None + + self.bind_f = bind_f + self.fallback = fallback + self.class_value = class_value + self.is_attr = is_attr + + def __set_name__(self, owner: LocalProxy[t.Any], name: str) -> None: + self.name = name + + def __get__(self, instance: LocalProxy[t.Any], owner: type | None = None) -> t.Any: + if instance is None: + if self.class_value is not None: + return self.class_value + + return self + + try: + obj = instance._get_current_object() + except RuntimeError: + if self.fallback is None: + raise + + fallback = self.fallback.__get__(instance, owner) + + if self.is_attr: + # __class__ and __doc__ are attributes, not methods. + # Call the fallback to get the value. + return fallback() + + return fallback + + if self.bind_f is not None: + return self.bind_f(instance, obj) + + return getattr(obj, self.name) + + def __repr__(self) -> str: + return f"proxy {self.name}" + + def __call__( + self, instance: LocalProxy[t.Any], *args: t.Any, **kwargs: t.Any + ) -> t.Any: + """Support calling unbound methods from the class. For example, + this happens with ``copy.copy``, which does + ``type(x).__copy__(x)``. ``type(x)`` can't be proxied, so it + returns the proxy type and descriptor. + """ + return self.__get__(instance, type(instance))(*args, **kwargs) + + +class _ProxyIOp(_ProxyLookup): + """Look up an augmented assignment method on a proxied object. The + method is wrapped to return the proxy instead of the object. + """ + + __slots__ = () + + def __init__( + self, + f: t.Callable[..., t.Any] | None = None, + fallback: t.Callable[[LocalProxy[t.Any]], t.Any] | None = None, + ) -> None: + super().__init__(f, fallback) + + def bind_f(instance: LocalProxy[t.Any], obj: t.Any) -> t.Callable[..., t.Any]: + def i_op(self: t.Any, other: t.Any) -> LocalProxy[t.Any]: + f(self, other) # type: ignore + return instance + + return i_op.__get__(obj, type(obj)) # type: ignore + + self.bind_f = bind_f + + +def _l_to_r_op(op: F) -> F: + """Swap the argument order to turn an l-op into an r-op.""" + + def r_op(obj: t.Any, other: t.Any) -> t.Any: + return op(other, obj) + + return t.cast(F, r_op) + + +def _identity(o: T) -> T: + return o + + +class LocalProxy(t.Generic[T]): + """A proxy to the object bound to a context-local object. All + operations on the proxy are forwarded to the bound object. If no + object is bound, a ``RuntimeError`` is raised. + + :param local: The context-local object that provides the proxied + object. + :param name: Proxy this attribute from the proxied object. + :param unbound_message: The error message to show if the + context-local object is unbound. + + Proxy a :class:`~contextvars.ContextVar` to make it easier to + access. Pass a name to proxy that attribute. + + .. code-block:: python + + _request_var = ContextVar("request") + request = LocalProxy(_request_var) + session = LocalProxy(_request_var, "session") + + Proxy an attribute on a :class:`Local` namespace by calling the + local with the attribute name: + + .. code-block:: python + + data = Local() + user = data("user") + + Proxy the top item on a :class:`LocalStack` by calling the local. + Pass a name to proxy that attribute. + + .. code-block:: + + app_stack = LocalStack() + current_app = app_stack() + g = app_stack("g") + + Pass a function to proxy the return value from that function. This + was previously used to access attributes of local objects before + that was supported directly. + + .. code-block:: python + + session = LocalProxy(lambda: request.session) + + ``__repr__`` and ``__class__`` are proxied, so ``repr(x)`` and + ``isinstance(x, cls)`` will look like the proxied object. Use + ``issubclass(type(x), LocalProxy)`` to check if an object is a + proxy. + + .. code-block:: python + + repr(user) # <User admin> + isinstance(user, User) # True + issubclass(type(user), LocalProxy) # True + + .. versionchanged:: 2.2.2 + ``__wrapped__`` is set when wrapping an object, not only when + wrapping a function, to prevent doctest from failing. + + .. versionchanged:: 2.2 + Can proxy a ``ContextVar`` or ``LocalStack`` directly. + + .. versionchanged:: 2.2 + The ``name`` parameter can be used with any proxied object, not + only ``Local``. + + .. versionchanged:: 2.2 + Added the ``unbound_message`` parameter. + + .. versionchanged:: 2.0 + Updated proxied attributes and methods to reflect the current + data model. + + .. versionchanged:: 0.6.1 + The class can be instantiated with a callable. + """ + + __slots__ = ("__wrapped", "_get_current_object") + + _get_current_object: t.Callable[[], T] + """Return the current object this proxy is bound to. If the proxy is + unbound, this raises a ``RuntimeError``. + + This should be used if you need to pass the object to something that + doesn't understand the proxy. It can also be useful for performance + if you are accessing the object multiple times in a function, rather + than going through the proxy multiple times. + """ + + def __init__( + self, + local: ContextVar[T] | Local | LocalStack[T] | t.Callable[[], T], + name: str | None = None, + *, + unbound_message: str | None = None, + ) -> None: + if name is None: + get_name = _identity + else: + get_name = attrgetter(name) # type: ignore[assignment] + + if unbound_message is None: + unbound_message = "object is not bound" + + if isinstance(local, Local): + if name is None: + raise TypeError("'name' is required when proxying a 'Local' object.") + + def _get_current_object() -> T: + try: + return get_name(local) # type: ignore[return-value] + except AttributeError: + raise RuntimeError(unbound_message) from None + + elif isinstance(local, LocalStack): + + def _get_current_object() -> T: + obj = local.top + + if obj is None: + raise RuntimeError(unbound_message) + + return get_name(obj) + + elif isinstance(local, ContextVar): + + def _get_current_object() -> T: + try: + obj = local.get() + except LookupError: + raise RuntimeError(unbound_message) from None + + return get_name(obj) + + elif callable(local): + + def _get_current_object() -> T: + return get_name(local()) + + else: + raise TypeError(f"Don't know how to proxy '{type(local)}'.") + + object.__setattr__(self, "_LocalProxy__wrapped", local) + object.__setattr__(self, "_get_current_object", _get_current_object) + + __doc__ = _ProxyLookup( # type: ignore[assignment] + class_value=__doc__, fallback=lambda self: type(self).__doc__, is_attr=True + ) + __wrapped__ = _ProxyLookup( + fallback=lambda self: self._LocalProxy__wrapped, # type: ignore[attr-defined] + is_attr=True, + ) + # __del__ should only delete the proxy + __repr__ = _ProxyLookup( # type: ignore[assignment] + repr, fallback=lambda self: f"<{type(self).__name__} unbound>" + ) + __str__ = _ProxyLookup(str) # type: ignore[assignment] + __bytes__ = _ProxyLookup(bytes) + __format__ = _ProxyLookup() # type: ignore[assignment] + __lt__ = _ProxyLookup(operator.lt) + __le__ = _ProxyLookup(operator.le) + __eq__ = _ProxyLookup(operator.eq) # type: ignore[assignment] + __ne__ = _ProxyLookup(operator.ne) # type: ignore[assignment] + __gt__ = _ProxyLookup(operator.gt) + __ge__ = _ProxyLookup(operator.ge) + __hash__ = _ProxyLookup(hash) # type: ignore[assignment] + __bool__ = _ProxyLookup(bool, fallback=lambda self: False) + __getattr__ = _ProxyLookup(getattr) + # __getattribute__ triggered through __getattr__ + __setattr__ = _ProxyLookup(setattr) # type: ignore[assignment] + __delattr__ = _ProxyLookup(delattr) # type: ignore[assignment] + __dir__ = _ProxyLookup(dir, fallback=lambda self: []) # type: ignore[assignment] + # __get__ (proxying descriptor not supported) + # __set__ (descriptor) + # __delete__ (descriptor) + # __set_name__ (descriptor) + # __objclass__ (descriptor) + # __slots__ used by proxy itself + # __dict__ (__getattr__) + # __weakref__ (__getattr__) + # __init_subclass__ (proxying metaclass not supported) + # __prepare__ (metaclass) + __class__ = _ProxyLookup(fallback=lambda self: type(self), is_attr=True) # type: ignore[assignment] + __instancecheck__ = _ProxyLookup(lambda self, other: isinstance(other, self)) + __subclasscheck__ = _ProxyLookup(lambda self, other: issubclass(other, self)) + # __class_getitem__ triggered through __getitem__ + __call__ = _ProxyLookup(lambda self, *args, **kwargs: self(*args, **kwargs)) + __len__ = _ProxyLookup(len) + __length_hint__ = _ProxyLookup(operator.length_hint) + __getitem__ = _ProxyLookup(operator.getitem) + __setitem__ = _ProxyLookup(operator.setitem) + __delitem__ = _ProxyLookup(operator.delitem) + # __missing__ triggered through __getitem__ + __iter__ = _ProxyLookup(iter) + __next__ = _ProxyLookup(next) + __reversed__ = _ProxyLookup(reversed) + __contains__ = _ProxyLookup(operator.contains) + __add__ = _ProxyLookup(operator.add) + __sub__ = _ProxyLookup(operator.sub) + __mul__ = _ProxyLookup(operator.mul) + __matmul__ = _ProxyLookup(operator.matmul) + __truediv__ = _ProxyLookup(operator.truediv) + __floordiv__ = _ProxyLookup(operator.floordiv) + __mod__ = _ProxyLookup(operator.mod) + __divmod__ = _ProxyLookup(divmod) + __pow__ = _ProxyLookup(pow) + __lshift__ = _ProxyLookup(operator.lshift) + __rshift__ = _ProxyLookup(operator.rshift) + __and__ = _ProxyLookup(operator.and_) + __xor__ = _ProxyLookup(operator.xor) + __or__ = _ProxyLookup(operator.or_) + __radd__ = _ProxyLookup(_l_to_r_op(operator.add)) + __rsub__ = _ProxyLookup(_l_to_r_op(operator.sub)) + __rmul__ = _ProxyLookup(_l_to_r_op(operator.mul)) + __rmatmul__ = _ProxyLookup(_l_to_r_op(operator.matmul)) + __rtruediv__ = _ProxyLookup(_l_to_r_op(operator.truediv)) + __rfloordiv__ = _ProxyLookup(_l_to_r_op(operator.floordiv)) + __rmod__ = _ProxyLookup(_l_to_r_op(operator.mod)) + __rdivmod__ = _ProxyLookup(_l_to_r_op(divmod)) + __rpow__ = _ProxyLookup(_l_to_r_op(pow)) + __rlshift__ = _ProxyLookup(_l_to_r_op(operator.lshift)) + __rrshift__ = _ProxyLookup(_l_to_r_op(operator.rshift)) + __rand__ = _ProxyLookup(_l_to_r_op(operator.and_)) + __rxor__ = _ProxyLookup(_l_to_r_op(operator.xor)) + __ror__ = _ProxyLookup(_l_to_r_op(operator.or_)) + __iadd__ = _ProxyIOp(operator.iadd) + __isub__ = _ProxyIOp(operator.isub) + __imul__ = _ProxyIOp(operator.imul) + __imatmul__ = _ProxyIOp(operator.imatmul) + __itruediv__ = _ProxyIOp(operator.itruediv) + __ifloordiv__ = _ProxyIOp(operator.ifloordiv) + __imod__ = _ProxyIOp(operator.imod) + __ipow__ = _ProxyIOp(operator.ipow) + __ilshift__ = _ProxyIOp(operator.ilshift) + __irshift__ = _ProxyIOp(operator.irshift) + __iand__ = _ProxyIOp(operator.iand) + __ixor__ = _ProxyIOp(operator.ixor) + __ior__ = _ProxyIOp(operator.ior) + __neg__ = _ProxyLookup(operator.neg) + __pos__ = _ProxyLookup(operator.pos) + __abs__ = _ProxyLookup(abs) + __invert__ = _ProxyLookup(operator.invert) + __complex__ = _ProxyLookup(complex) + __int__ = _ProxyLookup(int) + __float__ = _ProxyLookup(float) + __index__ = _ProxyLookup(operator.index) + __round__ = _ProxyLookup(round) + __trunc__ = _ProxyLookup(math.trunc) + __floor__ = _ProxyLookup(math.floor) + __ceil__ = _ProxyLookup(math.ceil) + __enter__ = _ProxyLookup() + __exit__ = _ProxyLookup() + __await__ = _ProxyLookup() + __aiter__ = _ProxyLookup() + __anext__ = _ProxyLookup() + __aenter__ = _ProxyLookup() + __aexit__ = _ProxyLookup() + __copy__ = _ProxyLookup(copy.copy) + __deepcopy__ = _ProxyLookup(copy.deepcopy) + # __getnewargs_ex__ (pickle through proxy not supported) + # __getnewargs__ (pickle) + # __getstate__ (pickle) + # __setstate__ (pickle) + # __reduce__ (pickle) + # __reduce_ex__ (pickle) |