Viewing file: linecache.py (2.81 KB) -rw-r--r-- Select action/file-type: (+) | (+) | (+) | Code (+) | Session (+) | (+) | SDB (+) | (+) | (+) | (+) | (+) | (+) |
"""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): lines = getlines(filename) 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): """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)
def checkcache(filename=None): """Discard cache entries that are out of date.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] 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): """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: # Try looking through the module search path. basename = os.path.split(filename)[1] 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 [] size, mtime = stat.st_size, stat.st_mtime cache[filename] = size, mtime, lines, fullname return lines
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