cpython/Lib/linecache.py

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"""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.
"""
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import sys
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import os
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__all__ = ["getline", "clearcache", "checkcache"]
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def getline(filename, lineno, module_globals=None):
lines = getlines(filename, module_globals)
if 1 <= lineno <= len(lines):
return lines[lineno-1]
else:
return ''
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# The cache
cache = {} # The cache
def clearcache():
"""Clear the cache entirely."""
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global cache
cache = {}
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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."""
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if filename in cache:
return cache[filename][2]
else:
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return updatecache(filename, module_globals)
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def checkcache(filename=None):
"""Discard cache entries that are out of date.
(This is not checked upon each call!)"""
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if filename is None:
filenames = 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]
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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[0] + filename[-1] == '<>':
return []
fullname = filename
try:
stat = os.stat(fullname)
except os.error, msg:
Merged revisions 72319-72320,72467,72661,72675-72679,72703,72708,72710,72712,72801-72802,72820,72822,72824,72826-72828,72830 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r72319 | georg.brandl | 2009-05-05 10:28:49 +0200 (Di, 05 Mai 2009) | 1 line #1309567: fix linecache behavior of stripping subdirectories from paths when looking for relative filename matches. Also add a linecache test suite. ........ r72320 | georg.brandl | 2009-05-05 10:30:28 +0200 (Di, 05 Mai 2009) | 1 line Add a news entry for r72319. ........ r72467 | georg.brandl | 2009-05-08 14:17:34 +0200 (Fr, 08 Mai 2009) | 1 line Fix name. ........ r72661 | georg.brandl | 2009-05-15 10:03:03 +0200 (Fr, 15 Mai 2009) | 1 line Fix example output for doctest-like demos. ........ r72675 | georg.brandl | 2009-05-16 13:13:21 +0200 (Sa, 16 Mai 2009) | 1 line #6034: clarify __reversed__ doc. ........ r72676 | georg.brandl | 2009-05-16 13:14:46 +0200 (Sa, 16 Mai 2009) | 1 line #6025: fix signature of parse(). ........ r72677 | georg.brandl | 2009-05-16 13:18:55 +0200 (Sa, 16 Mai 2009) | 1 line #6009: undocument default argument of Option as deprecated. ........ r72678 | georg.brandl | 2009-05-16 13:21:29 +0200 (Sa, 16 Mai 2009) | 1 line #2856: document 2.x os.listdir() behavior for undecodable filenames. ........ r72679 | georg.brandl | 2009-05-16 13:24:41 +0200 (Sa, 16 Mai 2009) | 1 line Fix about and bugs pages to match real workflow. ........ r72703 | georg.brandl | 2009-05-17 10:10:27 +0200 (So, 17 Mai 2009) | 1 line part of #4144: fix exception message in console session. ........ r72708 | georg.brandl | 2009-05-17 10:24:29 +0200 (So, 17 Mai 2009) | 1 line #6017: better document behavior of dictiterators when the dict is changed. ........ r72710 | georg.brandl | 2009-05-17 10:36:04 +0200 (So, 17 Mai 2009) | 1 line #5942: Copy over flag table from dbm.rst which is clearer. ........ r72712 | georg.brandl | 2009-05-17 10:55:00 +0200 (So, 17 Mai 2009) | 1 line #5935: mention that BROWSER is looked for in PATH. ........ r72801 | georg.brandl | 2009-05-20 20:31:14 +0200 (Mi, 20 Mai 2009) | 1 line #6055: refer to "sqlite3" consistently. ........ r72802 | georg.brandl | 2009-05-20 20:35:27 +0200 (Mi, 20 Mai 2009) | 1 line #6051: refer to email examples for better way to construct email messages. ........ r72820 | georg.brandl | 2009-05-22 09:23:32 +0200 (Fr, 22 Mai 2009) | 1 line Use raise X(y). ........ r72822 | georg.brandl | 2009-05-22 11:33:25 +0200 (Fr, 22 Mai 2009) | 1 line #6084: fix example. ........ r72824 | georg.brandl | 2009-05-22 11:43:17 +0200 (Fr, 22 Mai 2009) | 1 line Fix references to file-related functions and methods (os.* vs file.*). ........ r72826 | georg.brandl | 2009-05-22 11:49:42 +0200 (Fr, 22 Mai 2009) | 1 line Fix confusing wording. ........ r72827 | georg.brandl | 2009-05-22 11:50:30 +0200 (Fr, 22 Mai 2009) | 1 line s/use/call/ ........ r72828 | georg.brandl | 2009-05-22 11:58:48 +0200 (Fr, 22 Mai 2009) | 1 line Correction in softspace behavior description. ........ r72830 | georg.brandl | 2009-05-22 12:40:00 +0200 (Fr, 22 Mai 2009) | 1 line #6086: fix spelling and use a better exception to catch. ........
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basename = filename
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# Try for a __loader__, if available
if module_globals and '__loader__' in module_globals:
name = module_globals.get('__name__')
loader = module_globals['__loader__']
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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]
Merged revisions 72319-72320,72467,72661,72675-72679,72703,72708,72710,72712,72801-72802,72820,72822,72824,72826-72828,72830 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r72319 | georg.brandl | 2009-05-05 10:28:49 +0200 (Di, 05 Mai 2009) | 1 line #1309567: fix linecache behavior of stripping subdirectories from paths when looking for relative filename matches. Also add a linecache test suite. ........ r72320 | georg.brandl | 2009-05-05 10:30:28 +0200 (Di, 05 Mai 2009) | 1 line Add a news entry for r72319. ........ r72467 | georg.brandl | 2009-05-08 14:17:34 +0200 (Fr, 08 Mai 2009) | 1 line Fix name. ........ r72661 | georg.brandl | 2009-05-15 10:03:03 +0200 (Fr, 15 Mai 2009) | 1 line Fix example output for doctest-like demos. ........ r72675 | georg.brandl | 2009-05-16 13:13:21 +0200 (Sa, 16 Mai 2009) | 1 line #6034: clarify __reversed__ doc. ........ r72676 | georg.brandl | 2009-05-16 13:14:46 +0200 (Sa, 16 Mai 2009) | 1 line #6025: fix signature of parse(). ........ r72677 | georg.brandl | 2009-05-16 13:18:55 +0200 (Sa, 16 Mai 2009) | 1 line #6009: undocument default argument of Option as deprecated. ........ r72678 | georg.brandl | 2009-05-16 13:21:29 +0200 (Sa, 16 Mai 2009) | 1 line #2856: document 2.x os.listdir() behavior for undecodable filenames. ........ r72679 | georg.brandl | 2009-05-16 13:24:41 +0200 (Sa, 16 Mai 2009) | 1 line Fix about and bugs pages to match real workflow. ........ r72703 | georg.brandl | 2009-05-17 10:10:27 +0200 (So, 17 Mai 2009) | 1 line part of #4144: fix exception message in console session. ........ r72708 | georg.brandl | 2009-05-17 10:24:29 +0200 (So, 17 Mai 2009) | 1 line #6017: better document behavior of dictiterators when the dict is changed. ........ r72710 | georg.brandl | 2009-05-17 10:36:04 +0200 (So, 17 Mai 2009) | 1 line #5942: Copy over flag table from dbm.rst which is clearer. ........ r72712 | georg.brandl | 2009-05-17 10:55:00 +0200 (So, 17 Mai 2009) | 1 line #5935: mention that BROWSER is looked for in PATH. ........ r72801 | georg.brandl | 2009-05-20 20:31:14 +0200 (Mi, 20 Mai 2009) | 1 line #6055: refer to "sqlite3" consistently. ........ r72802 | georg.brandl | 2009-05-20 20:35:27 +0200 (Mi, 20 Mai 2009) | 1 line #6051: refer to email examples for better way to construct email messages. ........ r72820 | georg.brandl | 2009-05-22 09:23:32 +0200 (Fr, 22 Mai 2009) | 1 line Use raise X(y). ........ r72822 | georg.brandl | 2009-05-22 11:33:25 +0200 (Fr, 22 Mai 2009) | 1 line #6084: fix example. ........ r72824 | georg.brandl | 2009-05-22 11:43:17 +0200 (Fr, 22 Mai 2009) | 1 line Fix references to file-related functions and methods (os.* vs file.*). ........ r72826 | georg.brandl | 2009-05-22 11:49:42 +0200 (Fr, 22 Mai 2009) | 1 line Fix confusing wording. ........ r72827 | georg.brandl | 2009-05-22 11:50:30 +0200 (Fr, 22 Mai 2009) | 1 line s/use/call/ ........ r72828 | georg.brandl | 2009-05-22 11:58:48 +0200 (Fr, 22 Mai 2009) | 1 line Correction in softspace behavior description. ........ r72830 | georg.brandl | 2009-05-22 12:40:00 +0200 (Fr, 22 Mai 2009) | 1 line #6086: fix spelling and use a better exception to catch. ........
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# 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:
# When using imputil, sys.path may contain things other than
# strings; ignore them when it happens.
try:
fullname = os.path.join(dirname, basename)
except (TypeError, AttributeError):
# Not sufficiently string-like to do anything useful with.
pass
else:
try:
stat = os.stat(fullname)
break
except os.error:
pass
else:
# No luck
## print '*** Cannot stat', filename, ':', msg
return []
try:
fp = open(fullname, 'rU')
lines = fp.readlines()
fp.close()
except IOError, msg:
## print '*** Cannot open', fullname, ':', msg
return []
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