Files
python3-cookbook/cookbook/c10/p12_import_patch.py
2015-04-28 15:13:01 +08:00

67 lines
1.4 KiB
Python

#!/usr/bin/env python
# -*- encoding: utf-8 -*-
"""
Topic: sample
Desc :
"""
import importlib
import sys
from collections import defaultdict
_post_import_hooks = defaultdict(list)
class PostImportFinder:
def __init__(self):
self._skip = set()
def find_module(self, fullname, path=None):
if fullname in self._skip:
return None
self._skip.add(fullname)
return PostImportLoader(self)
class PostImportLoader:
def __init__(self, finder):
self._finder = finder
def load_module(self, fullname):
importlib.import_module(fullname)
module = sys.modules[fullname]
for func in _post_import_hooks[fullname]:
func(module)
self._finder._skip.remove(fullname)
return module
def when_imported(fullname):
def decorate(func):
if fullname in sys.modules:
func(sys.modules[fullname])
else:
_post_import_hooks[fullname].append(func)
return func
return decorate
sys.meta_path.insert(0, PostImportFinder())
from functools import wraps
def logged(func):
@wraps(func)
def wrapper(*args, **kwargs):
print('Calling', func.__name__, args, kwargs)
return func(*args, **kwargs)
return wrapper
# Example
@when_imported('math')
def add_logging(mod):
mod.cos = logged(mod.cos)
mod.sin = logged(mod.sin)