Add dircache module (#361)

Author: m4ns0ur

Makefile

@@ -96,6 +96,7 @@ STDLIB_TESTS := \
   test/test_colorsys \
   test/test_datetime \
   test/test_dict \
+  test/test_dircache \
   test/test_fpformat \
   test/test_genericpath \
   test/test_list \

third_party/stdlib/dircache.py

@@ -0,0 +1,41 @@
+"""Read and cache directory listings.
+
+The listdir() routine returns a sorted list of the files in a directory,
+using a cache to avoid reading the directory more often than necessary.
+The annotate() routine appends slashes to directories."""
+from warnings import warnpy3k
+warnpy3k("the dircache module has been removed in Python 3.0", stacklevel=2)
+del warnpy3k
+
+import os
+
+__all__ = ["listdir", "opendir", "annotate", "reset"]
+
+cache = {}
+
+def reset():
+    """Reset the cache completely."""
+    global cache
+    cache = {}
+
+def listdir(path):
+    """List directory contents, using cache."""
+    try:
+        cached_mtime, list = cache[path]
+        del cache[path]
+    except KeyError:
+        cached_mtime, list = -1, []
+    mtime = os.stat(path).st_mtime
+    if mtime != cached_mtime:
+        list = os.listdir(path)
+        list.sort()
+    cache[path] = mtime, list
+    return list
+
+opendir = listdir # XXX backward compatibility
+
+def annotate(head, list):
+    """Add '/' suffixes to directories."""
+    for i in range(len(list)):
+        if os.path.isdir(os.path.join(head, list[i])):
+            list[i] = list[i] + '/'

third_party/stdlib/test/test_dircache.py

@@ -0,0 +1,78 @@
+"""
+  Test cases for the dircache module
+  Nick Mathewson
+"""
+
+import unittest
+from test.test_support import run_unittest # , import_module
+# dircache = import_module('dircache', deprecated=True)
+import dircache
+import os, time, sys, tempfile
+
+
+class DircacheTests(unittest.TestCase):
+    def setUp(self):
+        self.tempdir = tempfile.mkdtemp()
+
+    def tearDown(self):
+        for fname in os.listdir(self.tempdir):
+            self.delTemp(fname)
+        os.rmdir(self.tempdir)
+
+    def writeTemp(self, fname):
+        f = open(os.path.join(self.tempdir, fname), 'w')
+        f.close()
+
+    def mkdirTemp(self, fname):
+        os.mkdir(os.path.join(self.tempdir, fname))
+
+    def delTemp(self, fname):
+        fname = os.path.join(self.tempdir, fname)
+        if os.path.isdir(fname):
+            os.rmdir(fname)
+        else:
+            os.unlink(fname)
+
+    def test_listdir(self):
+        ## SUCCESSFUL CASES
+        entries = dircache.listdir(self.tempdir)
+        self.assertEqual(entries, [])
+
+        # Check that cache is actually caching, not just passing through.
+        self.assertTrue(dircache.listdir(self.tempdir) is entries)
+
+        # Directories aren't "files" on Windows, and directory mtime has
+        # nothing to do with when files under a directory get created.
+        # That is, this test can't possibly work under Windows -- dircache
+        # is only good for capturing a one-shot snapshot there.
+
+        if sys.platform[:3] not in ('win', 'os2'):
+            # Sadly, dircache has the same granularity as stat.mtime, and so
+            # can't notice any changes that occurred within 1 sec of the last
+            # time it examined a directory.
+            time.sleep(1)
+            self.writeTemp("test1")
+            entries = dircache.listdir(self.tempdir)
+            self.assertEqual(entries, ['test1'])
+            self.assertTrue(dircache.listdir(self.tempdir) is entries)
+
+        ## UNSUCCESSFUL CASES
+        self.assertRaises(OSError, dircache.listdir, self.tempdir+"_nonexistent")
+
+    def test_annotate(self):
+        self.writeTemp("test2")
+        self.mkdirTemp("A")
+        lst = ['A', 'test2', 'test_nonexistent']
+        dircache.annotate(self.tempdir, lst)
+        self.assertEqual(lst, ['A/', 'test2', 'test_nonexistent'])
+
+
+def test_main():
+    try:
+        run_unittest(DircacheTests)
+    finally:
+        dircache.reset()
+
+
+if __name__ == "__main__":
+    test_main()