Initial revision
diff --git a/Lib/linecache.py b/Lib/linecache.py
new file mode 100644
index 0000000..4355f19
--- /dev/null
+++ b/Lib/linecache.py
@@ -0,0 +1,71 @@
+# Cache lines from files.
+
+import os
+from stat import *
+
+def getline(filename, lineno):
+ lines = getlines(filename)
+ if 1 <= lineno <= len(lines):
+ return lines[lineno-1]
+ else:
+ return ''
+
+
+# The cache
+
+cache = {} # The cache
+
+
+# Clear the cache entirely
+
+def clearcache():
+ global cache
+ cache = {}
+
+
+# Get the lines for a file from the cache.
+# Update the cache if it doesn't contain an entry for this file already.
+
+def getlines(filename):
+ if cache.has_key(filename):
+ return cache[filename][2]
+ else:
+ return updatecache(filename)
+
+
+# Discard cache entries that are out of date.
+# (This is not checked upon each call
+
+def checkcache():
+ for filename in cache.keys():
+ size, mtime, lines = cache[filename]
+ try: stat = os.stat(filename)
+ except os.error:
+ del cache[filename]
+ continue
+ if size <> stat[ST_SIZE] or mtime <> stat[ST_MTIME]:
+ del cache[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.
+
+def updatecache(filename):
+ try: del cache[filename]
+ except KeyError: pass
+ try: stat = os.stat(filename)
+ except os.error, msg:
+ if filename[0] + filename[-1] <> '<>':
+ print '*** Cannot stat', filename, ':', msg
+ return []
+ try:
+ fp = open(filename, 'r')
+ lines = fp.readlines()
+ fp.close()
+ except IOError, msg:
+ print '*** Cannot open', filename, ':', msg
+ return []
+ size, mtime = stat[ST_SIZE], stat[ST_MTIME]
+ cache[filename] = size, mtime, lines
+ return lines