Dont use win32com to get file associations

src/calibre/gui2/actions/view.py

@@ -10,7 +10,7 @@ from functools import partial
 
 from PyQt5.Qt import Qt, QAction, pyqtSignal
 
-from calibre.constants import isosx, iswindows
+from calibre.constants import isosx, iswindows, plugins
 from calibre.gui2 import (
     error_dialog, Dispatcher, question_dialog, config, open_local_file,
     info_dialog, elided_text)
@@ -18,6 +18,7 @@ from calibre.gui2.dialogs.choose_format import ChooseFormatDialog
 from calibre.utils.config import prefs, tweaks
 from calibre.ptempfile import PersistentTemporaryFile
 from calibre.gui2.actions import InterfaceAction
+from polyglot.builtins import unicode_type
 
 
 class HistoryAction(QAction):
@@ -125,11 +126,11 @@ class ViewAction(InterfaceAction):
                         kwargs=dict(args=args))
             else:
                 if iswindows:
-                    from calibre.utils.file_associations import file_assoc_windows
+                    winutil = plugins['winutil'][0]
                     ext = name.rpartition('.')[-1]
                     if ext:
                         try:
-                            prog = file_assoc_windows(ext)
+                            prog = winutil.file_association(unicode_type('.' + ext))
                         except Exception:
                             prog = None
                         if prog and prog.lower().endswith('calibre.exe'):

src/calibre/utils/file_associations.py

@@ -1,15 +0,0 @@
-#!/usr/bin/env python2
-# vim:fileencoding=utf-8
-from __future__ import absolute_import, division, print_function, unicode_literals
-
-__license__ = 'GPL v3'
-__copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
-
-
-def file_assoc_windows(ft):
-    # See the IQueryAssociations::GetString method documentation on MSDN
-    from win32com.shell import shell, shellcon
-    a = shell.AssocCreate()
-    a.Init(0, '.' + ft.lower())
-    return a.GetString(0, shellcon.ASSOCSTR_EXECUTABLE)
-

src/calibre/utils/windows/wintest.py

@@ -23,6 +23,10 @@ class TestWinutil(unittest.TestCase):
         self.winutil.add_to_recent_docs(path, None)
         self.winutil.add_to_recent_docs(path, 'some-app-uid')
 
+    def test_file_association(self):
+        self.assertIn('notepad.exe', self.winutil.file_association('.txt'))
+        self.assertIsNone(self.winutil.file_association('.mkjsfks'))
+
 
 def find_tests():
     return unittest.defaultTestLoader.loadTestsFromTestCase(TestWinutil)

src/calibre/utils/windows/winutil.c

@@ -376,6 +376,7 @@ winutil_strftime(PyObject *self, PyObject *args)
 
 static char winutil_doc[] = "Defines utility methods to interface with windows.";
 extern PyObject *add_to_recent_docs(PyObject *self, PyObject *args);
+extern PyObject *file_association(PyObject *self, PyObject *args);
 
 static PyMethodDef winutil_methods[] = {
     {"special_folder_path", winutil_folder_path, METH_VARARGS,
@@ -447,6 +448,10 @@ be a unicode string. Returns unicode strings."
         "add_to_recent_docs()\n\nAdd a path to the recent documents list"
     },
 
+    {"file_association", (PyCFunction)file_association, METH_VARARGS,
+        "file_association()\n\nGet the executable associated with the given file extension"
+    },
+
     {NULL, NULL, 0, NULL}
 };
 

src/calibre/utils/windows/winutilpp.cpp

@@ -10,6 +10,7 @@
 #include <Windows.h>
 #include <combaseapi.h>
 #include <shlobj.h>
+#include <shlwapi.h>
 #include <atlbase.h>  // for CComPtr
 #include <Python.h>
 
@@ -60,4 +61,13 @@ add_to_recent_docs(PyObject *self, PyObject *args) {
 }
 
 
+PyObject *
+file_association(PyObject *self, PyObject *args) {
+	wchar_t *ext, buf[2048];
+	DWORD sz = sizeof(buf);
+	if (!PyArg_ParseTuple(args, "O&", py_to_wchar, &ext)) return NULL;
+	HRESULT hr = AssocQueryStringW(0, ASSOCSTR_EXECUTABLE, ext, NULL, buf, &sz);
+	free_wchar_buffer(&ext);
+	if (!SUCCEEDED(hr)) Py_RETURN_NONE;
+	return Py_BuildValue("u#", buf, (int)sz);
 }