python: Robust exception handling in callbacks.

* lang/python/helpers.c (pygpgme_stash_callback_exception): New
function.
(pygpgme_raise_callback_exception): Likewise.
(pyPassphraseCb): Stash python errors.
* lang/python/helpers.h (pygpgme_raise_callback_exception): New
prototype.
* lang/python/pyme/core.py ({Context,Data}.__init__): Move common
initialization to superclass.
(Context.set_progress_cb): Hand in 'self'.
* lang/python/pyme/util.py (GpgmeWrapper.__init__): New function.
(GpgmeWrapper.__getattr__): Raise stashed exceptions.
* lang/python/tests/Makefile.am (py_tests): Add new test.
* lang/python/tests/t-callbacks.py: New file.

Signed-off-by: Justus Winter <[email protected]>

1 files changed, 77 insertions, 0 deletions

diff --git a/lang/python/tests/t-callbacks.py b/lang/python/tests/t-callbacks.py
new file mode 100755
index 00000000..e89fcb8d
--- /dev/null
+++ b/lang/python/tests/t-callbacks.py
@@ -0,0 +1,77 @@
+#!/usr/bin/env python3
+
+# Copyright (C) 2016 g10 Code GmbH
+#
+# This file is part of GPGME.
+#
+# GPGME is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# GPGME is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+# or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General
+# Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this program; if not, see <http://www.gnu.org/licenses/>.
+
+import os
+from pyme import core, constants
+import support
+
+support.init_gpgme(constants.PROTOCOL_OpenPGP)
+
+c = core.Context()
+c.set_pinentry_mode(constants.PINENTRY_MODE_LOOPBACK)
+
+source = core.Data("Hallo Leute\n")
+sink = core.Data()
+
+# Valid passphrases, both as string and bytes.
+for passphrase in ('foo', b'foo'):
+    def passphrase_cb(hint, desc, prev_bad, hook=None):
+        assert hook == passphrase
+        return hook
+
+    c.set_passphrase_cb(passphrase_cb, passphrase)
+    c.op_encrypt([], 0, source, sink)
+
+# Returning an invalid type.
+def passphrase_cb(hint, desc, prev_bad, hook=None):
+    return 0
+
+c.set_passphrase_cb(passphrase_cb, None)
+try:
+    c.op_encrypt([], 0, source, sink)
+except Exception as e:
+    assert type(e) == TypeError
+    assert str(e) == "expected str or bytes from passphrase callback, got int"
+else:
+    assert False, "Expected an error, got none"
+
+# Raising an exception inside callback.
+myException = Exception()
+def passphrase_cb(hint, desc, prev_bad, hook=None):
+    raise myException
+
+c.set_passphrase_cb(passphrase_cb, None)
+try:
+    c.op_encrypt([], 0, source, sink)
+except Exception as e:
+    assert e == myException
+else:
+    assert False, "Expected an error, got none"
+
+# Wrong kind of callback function.
+def bad_passphrase_cb():
+    pass
+
+c.set_passphrase_cb(bad_passphrase_cb, None)
+try:
+    c.op_encrypt([], 0, source, sink)
+except Exception as e:
+    assert type(e) == TypeError
+else:
+    assert False, "Expected an error, got none"