1 files changed, 82 insertions, 0 deletions
diff --git a/Lib/dos-8x3/statcach.py b/Lib/dos-8x3/statcach.py
new file mode 100755
index 0000000..770aef0
--- /dev/null
+++ b/Lib/dos-8x3/statcach.py
@@ -0,0 +1,82 @@
+# Module 'statcache'
+#
+# Maintain a cache of file stats.
+# There are functions to reset the cache or to selectively remove items.
+
+import os
+from stat import *
+
+# The cache.
+# Keys are pathnames, values are `os.stat' outcomes.
+#
+cache = {}
+
+
+# Stat a file, possibly out of the cache.
+#
+def stat(path):
+	if cache.has_key(path):
+		return cache[path]
+	cache[path] = ret = os.stat(path)
+	return ret
+
+
+# Reset the cache completely.
+#
+def reset():
+	global cache
+	cache = {}
+
+
+# Remove a given item from the cache, if it exists.
+#
+def forget(path):
+	if cache.has_key(path):
+		del cache[path]
+
+
+# Remove all pathnames with a given prefix.
+#
+def forget_prefix(prefix):
+	n = len(prefix)
+	for path in cache.keys():
+		if path[:n] == prefix:
+			del cache[path]
+
+
+# Forget about a directory and all entries in it, but not about
+# entries in subdirectories.
+#
+def forget_dir(prefix):
+	if prefix[-1:] == '/' and prefix <> '/':
+		prefix = prefix[:-1]
+	forget(prefix)
+	if prefix[-1:] <> '/':
+		prefix = prefix + '/'
+	n = len(prefix)
+	for path in cache.keys():
+		if path[:n] == prefix:
+			rest = path[n:]
+			if rest[-1:] == '/': rest = rest[:-1]
+			if '/' not in rest:
+				del cache[path]
+
+
+# Remove all pathnames except with a given prefix.
+# Normally used with prefix = '/' after a chdir().
+#
+def forget_except_prefix(prefix):
+	n = len(prefix)
+	for path in cache.keys():
+		if path[:n] <> prefix:
+			del cache[path]
+
+
+# Check for directory.
+#
+def isdir(path):
+	try:
+		st = stat(path)
+	except os.error:
+		return 0
+	return S_ISDIR(st[ST_MODE])