mirror of
https://github.com/python/cpython.git
synced 2024-11-25 02:44:06 +08:00
135 lines
3.8 KiB
Python
135 lines
3.8 KiB
Python
"""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"""Discard cache entries that are out of date.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 tokenize.open(fullname) as fp:
|
|
lines = fp.readlines()
|
|
except IOError:
|
|
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
|