python: Wrap objects implementing the buffer protocol.

* lang/python/Makefile.am: Add the toplevel source directory to CFLAGS
when compiling the bindings so that we can use private header files.
* lang/python/gpgme.i (gpgme_data_t): Rework the object wrapping.  Do
not create a Python wrapper object, merely a gpgme_data_t object, and
keep references to buffer objects, if any.  If necessary, update the
buffer after the function call.
(pygpgme_wrap_gpgme_data_t): New function.
* lang/python/helpers.c (object_to_gpgme_data_t): Rework object
wrapping.  Also wrap objects implementing the buffer protocol.
* lang/python/helpers.h (object_to_gpgme_data_t): Update prototype.
(pygpgme_wrap_gpgme_data_t): New prototype.
* lang/python/tests/t-idiomatic.py: Demonstrate this.

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

1 files changed, 6 insertions, 1 deletions

diff --git a/lang/python/helpers.h b/lang/python/helpers.h
index 24502631..37362aee 100644
--- a/lang/python/helpers.h
+++ b/lang/python/helpers.h
@@ -1,4 +1,5 @@
 /*
+# Copyright (C) 2016 g10 Code GmbH
 # Copyright (C) 2004 Igor Belyi <[email protected]>
 # Copyright (C) 2002 John Goerzen <[email protected]>
 #
@@ -30,7 +31,8 @@ gpgme_error_t pygpgme_exception2code(void);
 
 PyObject *object_to_gpgme_t(PyObject *input, const char *objtype, int argnum);
 PyObject *object_to_gpgme_data_t(PyObject *input, int argnum,
-				 PyObject **wrapper);
+				 gpgme_data_t *wrapper,
+				 PyObject **bytesio, Py_buffer *view);
 
 void pygpgme_clear_generic_cb(PyObject **cb);
 PyObject *pygpgme_raise_callback_exception(PyObject *self);
@@ -47,3 +49,6 @@ gpgme_error_t pyEditCb(void *opaque, gpgme_status_code_t status,
 gpgme_error_t pygpgme_data_new_from_cbs(gpgme_data_t *r_data,
                                         PyObject *pycbs,
                                         PyObject **freelater);
+
+/* SWIG support for helpers.c  */
+PyObject *pygpgme_wrap_gpgme_data_t(gpgme_data_t data);