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v0.5.1
v0.5.1
swh:1:snp:635f4099902912592851108bcac178ff574f7c5f
Tip revision: 74f4bd53e03ded8408bcc2de67cf0f5a4ac5b1a1 authored by Barry Warsaw on 23 February 2012, 15:59:38 UTC
Bump some more copyright years (as per PEP 101), since this is the first
Bump some more copyright years (as per PEP 101), since this is the first
Tip revision: 74f4bd5
linecache.py
"""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
__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"""Discard cache entries that are out of date.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 = 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[0] + filename[-1] == '<>':
return []
fullname = filename
try:
stat = os.stat(fullname)
except os.error, msg:
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:
# 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