Cours/venv/lib/python3.12/site-packages/watchdog/utils/echo.py

157 lines
5.2 KiB
Python

# echo.py: Tracing function calls using Python decorators.
#
# Written by Thomas Guest <tag@wordaligned.org>
# Please see http://wordaligned.org/articles/echo
#
# Place into the public domain.
"""Echo calls made to functions and methods in a module.
"Echoing" a function call means printing out the name of the function
and the values of its arguments before making the call (which is more
commonly referred to as "tracing", but Python already has a trace module).
Example: to echo calls made to functions in "my_module" do:
import echo
import my_module
echo.echo_module(my_module)
Example: to echo calls made to functions in "my_module.my_class" do:
echo.echo_class(my_module.my_class)
Alternatively, echo.echo can be used to decorate functions. Calls to the
decorated function will be echoed.
Example:
-------
@echo.echo
def my_function(args):
pass
"""
from __future__ import annotations
import inspect
import sys
from typing import TYPE_CHECKING
if TYPE_CHECKING:
from types import MethodType
from typing import Any, Callable
def name(item: Callable) -> str:
"""Return an item's name."""
return item.__name__
def is_classmethod(instancemethod: MethodType, klass: type) -> bool:
"""Determine if an instancemethod is a classmethod."""
return inspect.ismethod(instancemethod) and instancemethod.__self__ is klass
def is_static_method(method: MethodType, klass: type) -> bool:
"""Returns True if method is an instance method of klass."""
return next(
(isinstance(c.__dict__[name(method)], staticmethod) for c in klass.mro() if name(method) in c.__dict__),
False,
)
def is_class_private_name(name: str) -> bool:
"""Determine if a name is a class private name."""
# Exclude system defined names such as __init__, __add__ etc
return name.startswith("__") and not name.endswith("__")
def method_name(method: MethodType) -> str:
"""Return a method's name.
This function returns the name the method is accessed by from
outside the class (i.e. it prefixes "private" methods appropriately).
"""
mname = name(method)
if is_class_private_name(mname):
mname = f"_{name(method.__self__.__class__)}{mname}"
return mname
def format_arg_value(arg_val: tuple[str, tuple[Any, ...]]) -> str:
"""Return a string representing a (name, value) pair."""
arg, val = arg_val
return f"{arg}={val!r}"
def echo(fn: Callable, write: Callable[[str], int | None] = sys.stdout.write) -> Callable:
"""Echo calls to a function.
Returns a decorated version of the input function which "echoes" calls
made to it by writing out the function's name and the arguments it was
called with.
"""
import functools
# Unpack function's arg count, arg names, arg defaults
code = fn.__code__
argcount = code.co_argcount
argnames = code.co_varnames[:argcount]
fn_defaults: tuple[Any] = fn.__defaults__ or ()
argdefs = dict(list(zip(argnames[-len(fn_defaults) :], fn_defaults)))
@functools.wraps(fn)
def wrapped(*v: Any, **k: Any) -> Callable:
# Collect function arguments by chaining together positional,
# defaulted, extra positional and keyword arguments.
positional = list(map(format_arg_value, list(zip(argnames, v))))
defaulted = [format_arg_value((a, argdefs[a])) for a in argnames[len(v) :] if a not in k]
nameless = list(map(repr, v[argcount:]))
keyword = list(map(format_arg_value, list(k.items())))
args = positional + defaulted + nameless + keyword
write(f"{name(fn)}({', '.join(args)})\n")
return fn(*v, **k)
return wrapped
def echo_instancemethod(klass: type, method: MethodType, write: Callable[[str], int | None] = sys.stdout.write) -> None:
"""Change an instancemethod so that calls to it are echoed.
Replacing a classmethod is a little more tricky.
See: http://www.python.org/doc/current/ref/types.html
"""
mname = method_name(method)
# Avoid recursion printing method calls
if mname in {"__str__", "__repr__"}:
return
if is_classmethod(method, klass):
setattr(klass, mname, classmethod(echo(method.__func__, write)))
else:
setattr(klass, mname, echo(method, write))
def echo_class(klass: type, write: Callable[[str], int | None] = sys.stdout.write) -> None:
"""Echo calls to class methods and static functions"""
for _, method in inspect.getmembers(klass, inspect.ismethod):
# In python 3 only class methods are returned here
echo_instancemethod(klass, method, write)
for _, fn in inspect.getmembers(klass, inspect.isfunction):
if is_static_method(fn, klass):
setattr(klass, name(fn), staticmethod(echo(fn, write)))
else:
# It's not a class or a static method, so it must be an instance method.
echo_instancemethod(klass, fn, write)
def echo_module(mod: MethodType, write: Callable[[str], int | None] = sys.stdout.write) -> None:
"""Echo calls to functions and methods in a module."""
for fname, fn in inspect.getmembers(mod, inspect.isfunction):
setattr(mod, fname, echo(fn, write))
for _, klass in inspect.getmembers(mod, inspect.isclass):
echo_class(klass, write)