From 758f3e1452af00ca875c10b2fe770f98a3af293b Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Fri, 23 Oct 2020 20:46:44 +0530
Subject: [PATCH] Dont use win32 API function to make long paths useable as it
 fails on older windows

---
 setup/extensions.json                 |  2 +-
 src/calibre/test_build.py             |  2 --
 src/calibre/utils/filenames.py        |  7 ++++---
 src/calibre/utils/windows/winutil.cpp | 20 --------------------
 4 files changed, 5 insertions(+), 26 deletions(-)

diff --git a/setup/extensions.json b/setup/extensions.json
index 4638e5046c..2c9d5187de 100644
--- a/setup/extensions.json
+++ b/setup/extensions.json
@@ -141,7 +141,7 @@
         "only": "windows",
         "headers": "calibre/utils/windows/common.h",
         "sources": "calibre/utils/windows/winutil.cpp",
-        "libraries": "shell32 wininet advapi32 Pathcch",
+        "libraries": "shell32 wininet advapi32",
         "cflags": "/X"
     },
     {
diff --git a/src/calibre/test_build.py b/src/calibre/test_build.py
index 8f583d32ba..190157e899 100644
--- a/src/calibre/test_build.py
+++ b/src/calibre/test_build.py
@@ -261,8 +261,6 @@ class BuildTest(unittest.TestCase):
         self.assertRaises(OSError, winutil.create_mutex, 'test-mutex', False)
         m.close()
         self.assertEqual(winutil.parse_cmdline('"c:\\test exe.exe" "some arg" 2'), ('c:\\test exe.exe', 'some arg', '2'))
-        q = 'c:/hello/{}.txt'.format('a' * 400)
-        self.assertEqual(winutil.canonicalize_path(q), '\\\\?\\' + q)
 
     def test_sqlite(self):
         import sqlite3
diff --git a/src/calibre/utils/filenames.py b/src/calibre/utils/filenames.py
index 8f340ac827..e8a75b646f 100644
--- a/src/calibre/utils/filenames.py
+++ b/src/calibre/utils/filenames.py
@@ -595,10 +595,11 @@ rmtree = shutil.rmtree
 
 
 if iswindows:
+    long_path_prefix = '\\\\?\\'
+
     def make_long_path_useable(path):
-        if len(path) > 200:
-            from calibre_extensions.winutil import canonicalize_path
-            path = canonicalize_path(path)
+        if len(path) > 200 and os.path.isabs(path) and not path.startswith(long_path_prefix):
+            path = long_path_prefix + os.path.normpath(path)
         return path
 else:
     def make_long_path_useable(path):
diff --git a/src/calibre/utils/windows/winutil.cpp b/src/calibre/utils/windows/winutil.cpp
index 17fa709359..125cdd5e85 100644
--- a/src/calibre/utils/windows/winutil.cpp
+++ b/src/calibre/utils/windows/winutil.cpp
@@ -15,7 +15,6 @@
 #include <shlguid.h>
 #include <shellapi.h>
 #include <shlwapi.h>
-#include <pathcch.h>
 #include <commoncontrols.h>
 #include <comip.h>
 #include <comdef.h>
@@ -725,24 +724,6 @@ get_long_path_name(PyObject *self, PyObject *args) {
     return ans;
 }
 
-static PyObject *
-canonicalize_path(PyObject *self, PyObject *args) {
-    wchar_raii path;
-    if (!PyArg_ParseTuple(args, "O&", py_to_wchar_no_none, &path)) return NULL;
-	size_t path_len = 0;
-	wchar_t *p = path.ptr();
-	while (p[path_len]) {
-		if (p[path_len] == '/') p[path_len] = '\\';
-		path_len++;
-	}
-	wchar_t *ans;
-	HRESULT hr = PathAllocCanonicalize(p, PATHCCH_ENSURE_IS_EXTENDED_LENGTH_PATH, &ans);
-	if (FAILED(hr)) return error_from_hresult(hr, "Failed to canonicalize path", PyTuple_GET_ITEM(args, 0));
-	PyObject *r = PyUnicode_FromWideChar(ans, -1);
-	LocalFree(ans);
-	return r;
-}
-
 static PyObject *
 get_process_times(PyObject *self, PyObject *pid) {
     HANDLE h = INVALID_HANDLE_VALUE;
@@ -1025,7 +1006,6 @@ static PyMethodDef winutil_methods[] = {
     M(set_handle_information, METH_VARARGS),
     M(get_long_path_name, METH_VARARGS),
     M(get_process_times, METH_O),
-    M(canonicalize_path, METH_VARARGS),
 	M(get_handle_information, METH_VARARGS),
 	M(get_last_error, METH_NOARGS),
 	M(load_library, METH_VARARGS),