python: Support the Assuan engine.

* lang/python/gpgme.i: Add typemaps for the Assuan protocol callbacks.
* lang/python/helpers.c (_pyme_assuan_{data,inquire,status}_cb): New
functions.
* lang/python/private.h (_pyme_assuan_{data,inquire,status}_cb): New
prototypes.
* lang/python/pyme/core.py (Context.assuan_transact): New method.
* lang/python/pyme/util.py (percent_escape): New function.
* lang/python/tests/Makefile.am (py_tests): Add new test.
* lang/python/tests/t-protocol-assuan.py: New file.

Signed-off-by: Justus Winter <justus@g10code.com>

lang/python/gpgme.i

@@ -443,6 +443,60 @@
   $2 = $input;
 }
 
+
+
+/* The assuan protocol callbacks.  */
+%typemap(in) (gpgme_assuan_data_cb_t data_cb, void *data_cb_value) {
+  if ($input == Py_None)
+    $1 = $2 = NULL;
+  else
+    {
+      if (! PyTuple_Check($input))
+        return PyErr_Format(PyExc_TypeError, "callback must be a tuple");
+      if (PyTuple_Size($input) != 2)
+        return PyErr_Format(PyExc_TypeError,
+                            "callback must be a tuple of size 2");
+      if (! PyCallable_Check(PyTuple_GetItem($input, 1)))
+        return PyErr_Format(PyExc_TypeError, "second item must be callable");
+      $1 = _pyme_assuan_data_cb;
+      $2 = $input;
+    }
+}
+
+%typemap(in) (gpgme_assuan_inquire_cb_t inq_cb, void *inq_cb_value) {
+  if ($input == Py_None)
+    $1 = $2 = NULL;
+  else
+    {
+      if (! PyTuple_Check($input))
+        return PyErr_Format(PyExc_TypeError, "callback must be a tuple");
+      if (PyTuple_Size($input) != 2)
+        return PyErr_Format(PyExc_TypeError,
+                            "callback must be a tuple of size 2");
+      if (! PyCallable_Check(PyTuple_GetItem($input, 1)))
+        return PyErr_Format(PyExc_TypeError, "second item must be callable");
+      $1 = _pyme_assuan_inquire_cb;
+      $2 = $input;
+    }
+}
+
+%typemap(in) (gpgme_assuan_status_cb_t stat_cb, void *stat_cb_value) {
+  if ($input == Py_None)
+    $1 = $2 = NULL;
+  else
+    {
+      if (! PyTuple_Check($input))
+        return PyErr_Format(PyExc_TypeError, "callback must be a tuple");
+      if (PyTuple_Size($input) != 2)
+        return PyErr_Format(PyExc_TypeError,
+                            "callback must be a tuple of size 2");
+      if (! PyCallable_Check(PyTuple_GetItem($input, 1)))
+        return PyErr_Format(PyExc_TypeError, "second item must be callable");
+      $1 = _pyme_assuan_status_cb;
+      $2 = $input;
+    }
+}
+
 /* Include the unmodified <gpgme.h> for cc, and the cleaned-up local
    version for SWIG.  We do, however, want to hide certain fields on
    some structs, which we provide prior to including the version for

lang/python/helpers.c

@@ -937,3 +937,119 @@ pygpgme_data_new_from_cbs(PyObject *self,
   Py_INCREF(Py_None);
   return Py_None;
 }
+
+
+
+/* The assuan callbacks.  */
+
+gpgme_error_t
+_pyme_assuan_data_cb (void *hook, const void *data, size_t datalen)
+{
+  gpgme_error_t err = 0;
+  PyObject *pyhook = (PyObject *) hook;
+  PyObject *self = NULL;
+  PyObject *func = NULL;
+  PyObject *py_data = NULL;
+  PyObject *retval = NULL;
+
+  assert (PyTuple_Check(pyhook));
+  assert (PyTuple_Size(pyhook) == 2);
+  self = PyTuple_GetItem(pyhook, 0);
+  func = PyTuple_GetItem(pyhook, 1);
+  assert (PyCallable_Check(func));
+
+  py_data = PyBytes_FromStringAndSize(data, datalen);
+  if (py_data == NULL)
+    return NULL;	/* raise */
+
+  retval = PyObject_CallFunctionObjArgs(func, py_data, NULL);
+  if (PyErr_Occurred())
+    err = pygpgme_exception2code();
+  Py_DECREF(py_data);
+  Py_XDECREF(retval);
+
+ leave:
+  if (err)
+    pygpgme_stash_callback_exception(self);
+  return err;
+}
+
+gpgme_error_t
+_pyme_assuan_inquire_cb (void *hook, const char *name, const char *args,
+                         gpgme_data_t *r_data)
+{
+  gpgme_error_t err = 0;
+  PyObject *pyhook = (PyObject *) hook;
+  PyObject *self = NULL;
+  PyObject *func = NULL;
+  PyObject *py_name = NULL;
+  PyObject *py_args = NULL;
+  PyObject *retval = NULL;
+
+  assert (PyTuple_Check(pyhook));
+  assert (PyTuple_Size(pyhook) == 2);
+  self = PyTuple_GetItem(pyhook, 0);
+  func = PyTuple_GetItem(pyhook, 1);
+  assert (PyCallable_Check(func));
+
+  py_name = PyUnicode_FromString(name);
+  if (py_name == NULL)
+    return NULL;	/* raise */
+
+  py_args = PyUnicode_FromString(args);
+  if (py_args == NULL)
+    return NULL;	/* raise */
+
+  retval = PyObject_CallFunctionObjArgs(func, py_name, py_args, NULL);
+  if (PyErr_Occurred())
+    err = pygpgme_exception2code();
+  Py_DECREF(py_name);
+  Py_DECREF(py_args);
+  Py_XDECREF(retval);
+
+  /* FIXME: Returning data is not yet implemented.  */
+  r_data = NULL;
+
+ leave:
+  if (err)
+    pygpgme_stash_callback_exception(self);
+  return err;
+}
+
+gpgme_error_t
+_pyme_assuan_status_cb (void *hook, const char *status, const char *args)
+{
+  gpgme_error_t err = 0;
+  PyObject *pyhook = (PyObject *) hook;
+  PyObject *self = NULL;
+  PyObject *func = NULL;
+  PyObject *py_status = NULL;
+  PyObject *py_args = NULL;
+  PyObject *retval = NULL;
+
+  assert (PyTuple_Check(pyhook));
+  assert (PyTuple_Size(pyhook) == 2);
+  self = PyTuple_GetItem(pyhook, 0);
+  func = PyTuple_GetItem(pyhook, 1);
+  assert (PyCallable_Check(func));
+
+  py_status = PyUnicode_FromString(status);
+  if (py_status == NULL)
+    return NULL;	/* raise */
+
+  py_args = PyUnicode_FromString(args);
+  if (py_args == NULL)
+    return NULL;	/* raise */
+
+  retval = PyObject_CallFunctionObjArgs(func, py_status, py_args, NULL);
+  if (PyErr_Occurred())
+    err = pygpgme_exception2code();
+  Py_DECREF(py_status);
+  Py_DECREF(py_args);
+  Py_XDECREF(retval);
+
+ leave:
+  if (err)
+    pygpgme_stash_callback_exception(self);
+  return err;
+}

lang/python/private.h

@@ -35,4 +35,12 @@ PyObject *pygpgme_wrap_fragile_result(PyObject *fragile, const char *classname);
 gpgme_error_t pyEditCb(void *opaque, gpgme_status_code_t status,
 		       const char *args, int fd);
 
+gpgme_error_t _pyme_assuan_data_cb (void *hook,
+				    const void *data, size_t datalen);
+gpgme_error_t _pyme_assuan_inquire_cb (void *hook,
+				       const char *name, const char *args,
+				       gpgme_data_t *r_data);
+gpgme_error_t _pyme_assuan_status_cb (void *hook,
+				      const char *status, const char *args);
+
 #endif /* _PYME_PRIVATE_H_ */

lang/python/pyme/core.py

@@ -31,6 +31,7 @@ from . import pygpgme
 from .errors import errorcheck, GPGMEError
 from . import constants
 from . import errors
+from . import util
 
 class GpgmeWrapper(object):
     """Base wrapper class
@@ -467,6 +468,55 @@ class Context(GpgmeWrapper):
             plainbytes = data.read()
         return plainbytes, result
 
+    def assuan_transact(self, command,
+                        data_cb=None, inquire_cb=None, status_cb=None):
+        """Issue a raw assuan command
+
+        This function can be used to issue a raw assuan command to the
+        engine.
+
+        If command is a string or bytes, it will be used as-is.  If it
+        is an iterable of strings, it will be properly escaped and
+        joined into an well-formed assuan command.
+
+        Keyword arguments:
+        data_cb		-- a callback receiving data lines
+        inquire_cb	-- a callback providing more information
+        status_cb	-- a callback receiving status lines
+
+        Returns:
+        result		-- the result of command as GPGMEError
+
+        Raises:
+        GPGMEError	-- as signaled by the underlying library
+
+        """
+
+        if isinstance(command, (str, bytes)):
+            cmd = command
+        else:
+            cmd = " ".join(util.percent_escape(f) for f in command)
+
+        errptr = pygpgme.new_gpgme_error_t_p()
+
+        err = pygpgme.gpgme_op_assuan_transact_ext(
+            self.wrapped,
+            cmd,
+            (weakref.ref(self), data_cb) if data_cb else None,
+            (weakref.ref(self), inquire_cb) if inquire_cb else None,
+            (weakref.ref(self), status_cb) if status_cb else None,
+            errptr)
+
+        if self._callback_excinfo:
+            pygpgme.pygpgme_raise_callback_exception(self)
+
+        errorcheck(err)
+
+        status = pygpgme.gpgme_error_t_p_value(errptr)
+        pygpgme.delete_gpgme_error_t_p(errptr)
+
+        return GPGMEError(status) if status != 0 else None
+
     @property
     def signers(self):
         """Keys used for signing"""

lang/python/pyme/util.py

@@ -31,3 +31,9 @@ def process_constants(prefix, scope):
                  if identifier.startswith(prefix)}
     scope.update(constants)
     return list(constants.keys())
+
+def percent_escape(s):
+    return ''.join(
+        '%{0:2x}'.format(ord(c))
+        if c == '+' or c == '"' or c == '%' or ord(c) <= 0x20 else c
+        for c in s)

lang/python/tests/Makefile.am

@@ -49,7 +49,8 @@ py_tests = t-wrapper.py \
 	t-wait.py \
 	t-encrypt-large.py \
 	t-file-name.py \
-	t-idiomatic.py
+	t-idiomatic.py \
+	t-protocol-assuan.py
 
 TESTS = initial.py $(py_tests) final.py
 EXTRA_DIST = support.py $(TESTS) encrypt-only.asc sign-only.asc

lang/python/tests/t-protocol-assuan.py

@@ -0,0 +1,66 @@
+#!/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 pyme
+
+with pyme.Context(protocol=pyme.constants.PROTOCOL_ASSUAN) as c:
+    # Do nothing.
+    c.assuan_transact('nop')
+    c.assuan_transact('NOP')
+    c.assuan_transact(['NOP'])
+
+    err = c.assuan_transact('idontexist')
+    assert err.getsource() == pyme.errors.SOURCE_GPGAGENT
+    assert err.getcode() == pyme.errors.ASS_UNKNOWN_CMD
+
+    # Invoke the pinentry to get a confirmation.
+    c.assuan_transact(['GET_CONFIRMATION', 'Hello there'])
+
+    data = []
+    def data_cb(line):
+        data.append(line)
+
+    err = c.assuan_transact(['GETINFO', 'version'], data_cb=data_cb)
+    assert not err
+    assert len(data) == 1
+
+    data = []
+    err = c.assuan_transact(['GETINFO', 's2k_count'], data_cb=data_cb)
+    if not err:
+        assert len(data) == 1
+        assert int(data[0]) > 0
+
+    # XXX HELP sends status lines if we could use ASSUAN_CONVEY_COMMENTS.
+
+    status = []
+    def status_cb(line, args):
+        status.append((line, args))
+
+    alphas_grip = '76F7E2B35832976B50A27A282D9B87E44577EB66'
+    err = c.assuan_transact(['KEYINFO', alphas_grip], status_cb=status_cb)
+    if not err:
+        assert len(status) == 1
+        line, args = status[0]
+        assert line.startswith('KEYINFO')
+        assert args.startswith(alphas_grip)
+
+    # XXX: test these callbacks, e.g. using PRESET_PASSPHRASE
+    # XXX: once issue2428 is resolved
+    def inq_cb(name, args):
+        print("inq_cb", name, args)