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
|
"""Cache lines from files.
This is intended to read lines from modules imported -- hence if a filename
is not found, it will look down the module search path for a file by
that name.
"""
import sys
import os
import tokenize
__all__ = ["getline", "clearcache", "checkcache"]
def getline(filename, lineno, module_globals=None):
lines = getlines(filename, module_globals)
if 1 <= lineno <= len(lines):
return lines[lineno-1]
else:
return ''
# The cache
cache = {} # The cache
def clearcache():
"""Clear the cache entirely."""
global cache
cache = {}
def getlines(filename, module_globals=None):
"""Get the lines for a file from the cache.
Update the cache if it doesn't contain an entry for this file already."""
if filename in cache:
return cache[filename][2]
else:
return updatecache(filename, module_globals)
def checkcache(filename=None):
"""Discard cache entries that are out of date.
(This is not checked upon each call!)"""
if filename is None:
filenames = list(cache.keys())
else:
if filename in cache:
filenames = [filename]
else:
return
for filename in filenames:
size, mtime, lines, fullname = cache[filename]
if mtime is None:
continue # no-op for files loaded via a __loader__
try:
stat = os.stat(fullname)
except os.error:
del cache[filename]
continue
if size != stat.st_size or mtime != stat.st_mtime:
del cache[filename]
def updatecache(filename, module_globals=None):
"""Update a cache entry and return its list of lines.
If something's wrong, print a message, discard the cache entry,
and return an empty list."""
if filename in cache:
del cache[filename]
if not filename or (filename.startswith('<') and filename.endswith('>')):
return []
fullname = filename
try:
stat = os.stat(fullname)
except OSError:
basename = filename
# Try for a __loader__, if available
if module_globals and '__loader__' in module_globals:
name = module_globals.get('__name__')
loader = module_globals['__loader__']
get_source = getattr(loader, 'get_source', None)
if name and get_source:
try:
data = get_source(name)
except (ImportError, IOError):
pass
else:
if data is None:
# No luck, the PEP302 loader cannot find the source
# for this module.
return []
cache[filename] = (
len(data), None,
[line+'\n' for line in data.splitlines()], fullname
)
return cache[filename][2]
# Try looking through the module search path, which is only useful
# when handling a relative filename.
if os.path.isabs(filename):
return []
for dirname in sys.path:
try:
fullname = os.path.join(dirname, basename)
except (TypeError, AttributeError):
# Not sufficiently string-like to do anything useful with.
continue
try:
stat = os.stat(fullname)
break
except os.error:
pass
else:
return []
try:
with open(fullname, 'rb') as fp:
coding, line = tokenize.detect_encoding(fp.readline)
with open(fullname, 'r', encoding=coding) as fp:
lines = fp.readlines()
except IOError:
pass
if lines and not lines[-1].endswith('\n'):
lines[-1] += '\n'
size, mtime = stat.st_size, stat.st_mtime
cache[filename] = size, mtime, lines, fullname
return lines
|
