Python code coverage for Lib/linecache.py

#	count	content
1	n/a	"""Cache lines from Python source files.
2	n/a
3	n/a	This is intended to read lines from modules imported -- hence if a filename
4	n/a	is not found, it will look down the module search path for a file by
5	n/a	that name.
6	n/a	"""
7	n/a
8	n/a	import functools
9	n/a	import sys
10	n/a	import os
11	n/a	import tokenize
12	n/a
13	n/a	__all__ = ["getline", "clearcache", "checkcache"]
14	n/a
15	n/a	def getline(filename, lineno, module_globals=None):
16	n/a	lines = getlines(filename, module_globals)
17	n/a	if 1 <= lineno <= len(lines):
18	n/a	return lines[lineno-1]
19	n/a	else:
20	n/a	return ''
21	n/a
22	n/a
23	n/a	# The cache
24	n/a
25	n/a	# The cache. Maps filenames to either a thunk which will provide source code,
26	n/a	# or a tuple (size, mtime, lines, fullname) once loaded.
27	n/a	cache = {}
28	n/a
29	n/a
30	n/a	def clearcache():
31	n/a	"""Clear the cache entirely."""
32	n/a
33	n/a	global cache
34	n/a	cache = {}
35	n/a
36	n/a
37	n/a	def getlines(filename, module_globals=None):
38	n/a	"""Get the lines for a Python source file from the cache.
39	n/a	Update the cache if it doesn't contain an entry for this file already."""
40	n/a
41	n/a	if filename in cache:
42	n/a	entry = cache[filename]
43	n/a	if len(entry) != 1:
44	n/a	return cache[filename][2]
45	n/a
46	n/a	try:
47	n/a	return updatecache(filename, module_globals)
48	n/a	except MemoryError:
49	n/a	clearcache()
50	n/a	return []
51	n/a
52	n/a
53	n/a	def checkcache(filename=None):
54	n/a	"""Discard cache entries that are out of date.
55	n/a	(This is not checked upon each call!)"""
56	n/a
57	n/a	if filename is None:
58	n/a	filenames = list(cache.keys())
59	n/a	else:
60	n/a	if filename in cache:
61	n/a	filenames = [filename]
62	n/a	else:
63	n/a	return
64	n/a
65	n/a	for filename in filenames:
66	n/a	entry = cache[filename]
67	n/a	if len(entry) == 1:
68	n/a	# lazy cache entry, leave it lazy.
69	n/a	continue
70	n/a	size, mtime, lines, fullname = entry
71	n/a	if mtime is None:
72	n/a	continue # no-op for files loaded via a __loader__
73	n/a	try:
74	n/a	stat = os.stat(fullname)
75	n/a	except OSError:
76	n/a	del cache[filename]
77	n/a	continue
78	n/a	if size != stat.st_size or mtime != stat.st_mtime:
79	n/a	del cache[filename]
80	n/a
81	n/a
82	n/a	def updatecache(filename, module_globals=None):
83	n/a	"""Update a cache entry and return its list of lines.
84	n/a	If something's wrong, print a message, discard the cache entry,
85	n/a	and return an empty list."""
86	n/a
87	n/a	if filename in cache:
88	n/a	if len(cache[filename]) != 1:
89	n/a	del cache[filename]
90	n/a	if not filename or (filename.startswith('<') and filename.endswith('>')):
91	n/a	return []
92	n/a
93	n/a	fullname = filename
94	n/a	try:
95	n/a	stat = os.stat(fullname)
96	n/a	except OSError:
97	n/a	basename = filename
98	n/a
99	n/a	# Realise a lazy loader based lookup if there is one
100	n/a	# otherwise try to lookup right now.
101	n/a	if lazycache(filename, module_globals):
102	n/a	try:
103	n/a	data = cache[filename][0]()
104	n/a	except (ImportError, OSError):
105	n/a	pass
106	n/a	else:
107	n/a	if data is None:
108	n/a	# No luck, the PEP302 loader cannot find the source
109	n/a	# for this module.
110	n/a	return []
111	n/a	cache[filename] = (
112	n/a	len(data), None,
113	n/a	[line+'\n' for line in data.splitlines()], fullname
114	n/a	)
115	n/a	return cache[filename][2]
116	n/a
117	n/a	# Try looking through the module search path, which is only useful
118	n/a	# when handling a relative filename.
119	n/a	if os.path.isabs(filename):
120	n/a	return []
121	n/a
122	n/a	for dirname in sys.path:
123	n/a	try:
124	n/a	fullname = os.path.join(dirname, basename)
125	n/a	except (TypeError, AttributeError):
126	n/a	# Not sufficiently string-like to do anything useful with.
127	n/a	continue
128	n/a	try:
129	n/a	stat = os.stat(fullname)
130	n/a	break
131	n/a	except OSError:
132	n/a	pass
133	n/a	else:
134	n/a	return []
135	n/a	try:
136	n/a	with tokenize.open(fullname) as fp:
137	n/a	lines = fp.readlines()
138	n/a	except OSError:
139	n/a	return []
140	n/a	if lines and not lines[-1].endswith('\n'):
141	n/a	lines[-1] += '\n'
142	n/a	size, mtime = stat.st_size, stat.st_mtime
143	n/a	cache[filename] = size, mtime, lines, fullname
144	n/a	return lines
145	n/a
146	n/a
147	n/a	def lazycache(filename, module_globals):
148	n/a	"""Seed the cache for filename with module_globals.
149	n/a
150	n/a	The module loader will be asked for the source only when getlines is
151	n/a	called, not immediately.
152	n/a
153	n/a	If there is an entry in the cache already, it is not altered.
154	n/a
155	n/a	:return: True if a lazy load is registered in the cache,
156	n/a	otherwise False. To register such a load a module loader with a
157	n/a	get_source method must be found, the filename must be a cachable
158	n/a	filename, and the filename must not be already cached.
159	n/a	"""
160	n/a	if filename in cache:
161	n/a	if len(cache[filename]) == 1:
162	n/a	return True
163	n/a	else:
164	n/a	return False
165	n/a	if not filename or (filename.startswith('<') and filename.endswith('>')):
166	n/a	return False
167	n/a	# Try for a __loader__, if available
168	n/a	if module_globals and '__loader__' in module_globals:
169	n/a	name = module_globals.get('__name__')
170	n/a	loader = module_globals['__loader__']
171	n/a	get_source = getattr(loader, 'get_source', None)
172	n/a
173	n/a	if name and get_source:
174	n/a	get_lines = functools.partial(get_source, name)
175	n/a	cache[filename] = (get_lines,)
176	n/a	return True
177	n/a	return False