python: Fix writing to data buffers.

* lang/python/gpgme.i: Add typemap for buffers.
* lang/python/pyme/core.py (Data.write): Fix function.
* lang/python/tests/Makefile.am: Add new test.
* lang/python/tests/t-data.py: New file.

Signed-off-by: Justus Winter <justus@gnupg.org>

lang/python/gpgme.i

@@ -173,6 +173,23 @@ PyObject* object_to_gpgme_t(PyObject* input, const char* objtype, int argnum) {
   free($1);
 }
 
+/* For gpgme_data_write, but should be universal.  */
+%typemap(in) (const void *buffer, size_t size) {
+  if ($input == Py_None)
+    $1 = NULL, $2 = 0;
+  else if (PyUnicode_Check($input))
+    $1 = PyUnicode_AsUTF8AndSize($input, (size_t *) &$2);
+  else if (PyBytes_Check($input))
+    PyBytes_AsStringAndSize($input, (char **) &$1, (size_t *) &$2);
+  else {
+    PyErr_Format(PyExc_TypeError,
+                 "arg %d: expected str, bytes, or None, got %s",
+		 $argnum, $input->ob_type->tp_name);
+    return NULL;
+  }
+}
+%typemap(freearg) (const void *buffer, size_t size) "";
+
 // Make types containing 'next' field to be lists
 %ignore next;
 %typemap(out) gpgme_sig_notation_t, gpgme_engine_info_t, gpgme_subkey_t, gpgme_key_sig_t,

lang/python/pyme/core.py

@@ -391,8 +391,10 @@ class Data(GpgmeWrapper):
         self.new_from_fd(file)
 
     def write(self, buffer):
-        """Write buffer given as bytes."""
-        errorcheck(pygpgme.gpgme_data_write(self.wrapped, buffer, len(buffer)))
+        """Write buffer given as string or bytes.
+
+        If a string is given, it is implicitly encoded using UTF-8."""
+        return pygpgme.gpgme_data_write(self.wrapped, buffer)
 
     def read(self, size = -1):
         """Read at most size bytes, returned as bytes.

lang/python/tests/Makefile.am

@@ -19,4 +19,4 @@
 TESTS_ENVIRONMENT = GNUPGHOME=$(abs_builddir) \
 	PYTHONPATH=`echo $(abs_builddir)/../build/lib.*`
 
-TESTS = t-wrapper.py
+TESTS = t-wrapper.py t-data.py

lang/python/tests/t-data.py

@@ -0,0 +1,49 @@
+#!/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
+
+data = core.Data('Hello world!')
+assert data.read() == b'Hello world!'
+assert data.read() == b''
+
+data.seek(0, os.SEEK_SET)
+assert data.read() == b'Hello world!'
+assert data.read() == b''
+
+data = core.Data(b'Hello world!')
+assert data.read() == b'Hello world!'
+
+data = core.Data()
+data.write('Hello world!')
+data.seek(0, os.SEEK_SET)
+assert data.read() == b'Hello world!'
+
+data = core.Data()
+data.write(b'Hello world!')
+data.seek(0, os.SEEK_SET)
+assert data.read() == b'Hello world!'
+
+binjunk = bytes(range(256))
+data = core.Data()
+data.write(binjunk)
+data.seek(0, os.SEEK_SET)
+assert data.read() == binjunk