forked from enshahar/effectivepython_3rd_kor
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathitem_066.py
More file actions
executable file
·273 lines (212 loc) · 5.88 KB
/
item_066.py
File metadata and controls
executable file
·273 lines (212 loc) · 5.88 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
#!/usr/bin/env PYTHONHASHSEED=1234 python3
# Copyright 2014-2024 Brett Slatkin, Pearson Education Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
### 책 예제에 맞는 환경 설정을 시작함
import random
random.seed(1234)
import logging
from pprint import pprint
from sys import stdout as STDOUT
# 모든 출력을 임시 디렉터리로 보냄
import atexit
import gc
import io
import os
import tempfile
TEST_DIR = tempfile.TemporaryDirectory()
atexit.register(TEST_DIR.cleanup)
# 윈도우에서 프로세스가 제대로 종료되도록 함
OLD_CWD = os.getcwd()
atexit.register(lambda: os.chdir(OLD_CWD))
os.chdir(TEST_DIR.name)
def close_open_files():
everything = gc.get_objects()
for obj in everything:
if isinstance(obj, io.IOBase):
obj.close()
atexit.register(close_open_files)
### 책 예제에 맞는 환경설정 끝
print("아이템 66")
print("Example 1")
from functools import wraps
def trace_func(func):
if hasattr(func, "tracing"): # 단 한번만 데코레이터를 적용한다
return func
@wraps(func)
def wrapper(*args, **kwargs):
args_repr = repr(args)
kwargs_repr = repr(kwargs)
result = None
try:
result = func(*args, **kwargs)
return result
except Exception as e:
result = e
raise
finally:
print(
f"{func.__name__}"
f"({args_repr}, {kwargs_repr}) -> "
f"{result!r}"
)
wrapper.tracing = True
return wrapper
print("Example 2")
class TraceDict(dict):
@trace_func
def __init__(self, *args, **kwargs):
return super().__init__(*args, **kwargs)
@trace_func
def __setitem__(self, *args, **kwargs):
return super().__setitem__(*args, **kwargs)
@trace_func
def __getitem__(self, *args, **kwargs):
return super().__getitem__(*args, **kwargs)
print("Example 3")
trace_dict = TraceDict([("hi", 1)])
trace_dict["there"] = 2
trace_dict["hi"]
try:
trace_dict["존재하지 않음"]
except KeyError:
pass # 이 문장이 실행되리라 예상함
else:
assert False
print("Example 4")
import types
TRACE_TYPES = (
types.MethodType,
types.FunctionType,
types.BuiltinFunctionType,
types.BuiltinMethodType,
types.MethodDescriptorType,
types.ClassMethodDescriptorType,
types.WrapperDescriptorType,
)
IGNORE_METHODS = (
"__repr__",
"__str__",
)
class TraceMeta(type):
def __new__(meta, name, bases, class_dict):
klass = super().__new__(meta, name, bases, class_dict)
for key in dir(klass):
if key in IGNORE_METHODS:
continue
value = getattr(klass, key)
if not isinstance(value, TRACE_TYPES):
continue
wrapped = trace_func(value)
setattr(klass, key, wrapped)
return klass
print("Example 5")
class TraceDict(dict, metaclass=TraceMeta):
pass
trace_dict = TraceDict([("hi", 1)])
trace_dict["there"] = 2
trace_dict["hi"]
try:
trace_dict["존재하지 않음"]
except KeyError:
pass # 이 문장이 실행되리라 예상함
else:
assert False
print("Example 6")
try:
class OtherMeta(type):
pass
class SimpleDict(dict, metaclass=OtherMeta):
pass
class ChildTraceDict(SimpleDict, metaclass=TraceMeta):
pass
except:
logging.exception('이 예외가 발생해야 함')
else:
assert False
print("Example 7")
class TraceMeta(type):
def __new__(meta, name, bases, class_dict):
klass = super().__new__(meta, name, bases, class_dict)
for key in dir(klass):
if key in IGNORE_METHODS:
continue
value = getattr(klass, key)
if not isinstance(value, TRACE_TYPES):
continue
wrapped = trace_func(value)
setattr(klass, key, wrapped)
return klass
class OtherMeta(TraceMeta):
pass
class SimpleDict(dict, metaclass=OtherMeta):
pass
class ChildTraceDict(SimpleDict, metaclass=TraceMeta):
pass
trace_dict = ChildTraceDict([("hi", 1)])
trace_dict["there"] = 2
trace_dict["hi"]
try:
trace_dict["존재하지 않음"]
except KeyError:
pass # 이 문장이 실행되리라 예상함
else:
assert False
print("Example 8")
def my_class_decorator(klass):
klass.extra_param = "hello"
return klass
@my_class_decorator
class MyClass:
pass
print(MyClass)
print(MyClass.extra_param)
print("Example 9")
def trace(klass):
for key in dir(klass):
if key in IGNORE_METHODS:
continue
value = getattr(klass, key)
if not isinstance(value, TRACE_TYPES):
continue
wrapped = trace_func(value)
setattr(klass, key, wrapped)
return klass
print("Example 10")
@trace
class DecoratedTraceDict(dict):
pass
trace_dict = DecoratedTraceDict([("hi", 1)])
trace_dict["there"] = 2
trace_dict["hi"]
try:
trace_dict["존재하지 않음"]
except KeyError:
pass # 이 문장이 실행되리라 예상함
else:
assert False
print("Example 11")
class OtherMeta(type):
pass
@trace
class HasMetaTraceDict(dict, metaclass=OtherMeta):
pass
trace_dict = HasMetaTraceDict([("hi", 1)])
trace_dict["there"] = 2
trace_dict["hi"]
try:
trace_dict["존재하지 않음"]
except KeyError:
pass # 이 문장이 실행되리라 예상함
else:
assert False