Fix #11583. Changed os.path.isdir to use GetFileAttributes instead of os.stat.
By changing to the Windows GetFileAttributes API in nt._isdir we can figure
out if the path is a directory without opening the file via os.stat. This has
the minor benefit of speeding up os.path.isdir by at least 2x for regular
files and 10-15x improvements were seen on symbolic links (which opened the
file multiple times during os.stat). Since os.path.isdir is used in
several places on interpreter startup, we get a minor speedup in startup time.
diff --git a/Lib/ntpath.py b/Lib/ntpath.py
index ec8a7ab..2483ced 100644
--- a/Lib/ntpath.py
+++ b/Lib/ntpath.py
@@ -672,3 +672,16 @@
def sameopenfile(f1, f2):
"""Test whether two file objects reference the same file"""
return _getfileinformation(f1) == _getfileinformation(f2)
+
+
+try:
+ # The genericpath.isdir implementation uses os.stat and checks the mode
+ # attribute to tell whether or not the path is a directory.
+ # This is overkill on Windows - just pass the path to GetFileAttributes
+ # and check the attribute from there.
+ from nt import _isdir
+except ImportError:
+ from genericpath import isdir as _isdir
+
+def isdir(path):
+ return _isdir(path)
diff --git a/Misc/NEWS b/Misc/NEWS
index 16a0f29..15ed46f 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -22,6 +22,9 @@
Library
-------
+- Issue #11583: Speed up os.path.isdir on Windows by using GetFileAttributes
+ instead of os.stat.
+
- Named tuples now work correctly with vars().
- Issue #12085: Fix an attribute error in subprocess.Popen destructor if the
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 89d3f2f..767ed61 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -2819,6 +2819,42 @@
info.nFileIndexHigh,
info.nFileIndexLow);
}
+
+static PyObject *
+posix__isdir(PyObject *self, PyObject *args)
+{
+ PyObject *opath;
+ char *path;
+ PyUnicodeObject *po;
+ DWORD attributes;
+
+ if (PyArg_ParseTuple(args, "U|:_isdir", &po)) {
+ Py_UNICODE *wpath = PyUnicode_AS_UNICODE(po);
+
+ attributes = GetFileAttributesW(wpath);
+ if (attributes == INVALID_FILE_ATTRIBUTES)
+ Py_RETURN_FALSE;
+ goto check;
+ }
+ /* Drop the argument parsing error as narrow strings
+ are also valid. */
+ PyErr_Clear();
+
+ if (!PyArg_ParseTuple(args, "O&:_isdir",
+ PyUnicode_FSConverter, &opath))
+ return NULL;
+
+ path = PyBytes_AsString(opath);
+ attributes = GetFileAttributesA(path);
+ if (attributes == INVALID_FILE_ATTRIBUTES)
+ Py_RETURN_FALSE;
+
+check:
+ if (attributes & FILE_ATTRIBUTE_DIRECTORY)
+ Py_RETURN_TRUE;
+ else
+ Py_RETURN_FALSE;
+}
#endif /* MS_WINDOWS */
PyDoc_STRVAR(posix_mkdir__doc__,
@@ -8055,6 +8091,7 @@
{"_getfullpathname", posix__getfullpathname, METH_VARARGS, NULL},
{"_getfinalpathname", posix__getfinalpathname, METH_VARARGS, NULL},
{"_getfileinformation", posix__getfileinformation, METH_VARARGS, NULL},
+ {"_isdir", posix__isdir, METH_VARARGS, NULL},
#endif
#ifdef HAVE_GETLOADAVG
{"getloadavg", posix_getloadavg, METH_NOARGS, posix_getloadavg__doc__},