[libsigrokdecode.git] / session.c

/*
 * This file is part of the libsigrokdecode project.
 *
 * Copyright (C) 2010 Uwe Hermann <uwe@hermann-uwe.de>
 * Copyright (C) 2013 Bert Vermeulen <bert@biot.com>
 *
 * This program 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 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <config.h>
#include "libsigrokdecode-internal.h" /* First, so we avoid a _POSIX_C_SOURCE warning. */
#include "libsigrokdecode.h"
#include <inttypes.h>
#include <glib.h>

/**
 * @file
 *
 * Session handling.
 */

/**
 * @defgroup grp_session Session handling
 *
 * Starting and handling decoding sessions.
 *
 * @{
 */

/** @cond PRIVATE */

SRD_PRIV GSList *sessions = NULL;
SRD_PRIV int max_session_id = -1;

/** @endcond */

/** @private */
SRD_PRIV int session_is_valid(struct srd_session *sess)
{

	if (!sess || sess->session_id < 1)
		return SRD_ERR;

	return SRD_OK;
}

/**
 * Create a decoding session.
 *
 * A session holds all decoder instances, their stack relationships and
 * output callbacks.
 *
 * @param sess A pointer which will hold a pointer to a newly
 *             initialized session on return.
 *
 * @return SRD_OK upon success, a (negative) error code otherwise.
 *
 * @since 0.3.0
 */
SRD_API int srd_session_new(struct srd_session **sess)
{

	if (!sess) {
		srd_err("Invalid session pointer.");
		return SRD_ERR_ARG;
	}

	*sess = g_malloc(sizeof(struct srd_session));
	(*sess)->session_id = ++max_session_id;
	(*sess)->di_list = (*sess)->callbacks = NULL;

	/* Keep a list of all sessions, so we can clean up as needed. */
	sessions = g_slist_append(sessions, *sess);

	srd_dbg("Created session %d.", (*sess)->session_id);

	return SRD_OK;
}

/**
 * Start a decoding session.
 *
 * Decoders, instances and stack must have been prepared beforehand,
 * and all SRD_CONF parameters set.
 *
 * @param sess The session to start.
 *
 * @return SRD_OK upon success, a (negative) error code otherwise.
 *
 * @since 0.3.0
 */
SRD_API int srd_session_start(struct srd_session *sess)
{
	GSList *d;
	struct srd_decoder_inst *di;
	int ret;

	if (session_is_valid(sess) != SRD_OK) {
		srd_err("Invalid session pointer.");
		return SRD_ERR;
	}

	srd_dbg("Calling start() on all instances in session %d.", sess->session_id);

	/* Run the start() method on all decoders receiving frontend data. */
	ret = SRD_OK;
	for (d = sess->di_list; d; d = d->next) {
		di = d->data;
		if ((ret = srd_inst_start(di)) != SRD_OK)
			break;
	}

	return ret;
}

static int srd_inst_send_meta(struct srd_decoder_inst *di, int key,
		GVariant *data)
{
	PyObject *py_ret;
	GSList *l;
	struct srd_decoder_inst *next_di;
	int ret;
	PyGILState_STATE gstate;

	if (key != SRD_CONF_SAMPLERATE)
		/* This is the only key we pass on to the decoder for now. */
		return SRD_OK;

	gstate = PyGILState_Ensure();

	if (PyObject_HasAttrString(di->py_inst, "metadata")) {
		py_ret = PyObject_CallMethod(di->py_inst, "metadata", "lK",
				(long)SRD_CONF_SAMPLERATE,
				(unsigned long long)g_variant_get_uint64(data));
		Py_XDECREF(py_ret);
	}

	PyGILState_Release(gstate);

	/* Push metadata to all the PDs stacked on top of this one. */
	for (l = di->next_di; l; l = l->next) {
		next_di = l->data;
		if ((ret = srd_inst_send_meta(next_di, key, data)) != SRD_OK)
			return ret;
	}

	return SRD_OK;
}

/**
 * Set a metadata configuration key in a session.
 *
 * @param sess The session to configure.
 * @param key The configuration key (SRD_CONF_*).
 * @param data The new value for the key, as a GVariant with GVariantType
 *             appropriate to that key. A floating reference can be passed
 *             in; its refcount will be sunk and unreferenced after use.
 *
 * @return SRD_OK upon success, a (negative) error code otherwise.
 *
 * @since 0.3.0
 */
SRD_API int srd_session_metadata_set(struct srd_session *sess, int key,
		GVariant *data)
{
	GSList *l;
	int ret;

	if (session_is_valid(sess) != SRD_OK) {
		srd_err("Invalid session.");
		return SRD_ERR_ARG;
	}

	if (!key) {
		srd_err("Invalid key.");
		return SRD_ERR_ARG;
	}

	if (!data) {
		srd_err("Invalid value.");
		return SRD_ERR_ARG;
	}

	/* Hardcoded to samplerate/uint64 for now. */

	if (key != SRD_CONF_SAMPLERATE) {
		srd_err("Unknown config key %d.", key);
		return SRD_ERR_ARG;
	}
	if (!g_variant_is_of_type(data, G_VARIANT_TYPE_UINT64)) {
		srd_err("Invalid value type: expected uint64, got %s",
				g_variant_get_type_string(data));
		return SRD_ERR_ARG;
	}

	srd_dbg("Setting session %d samplerate to %"G_GUINT64_FORMAT".",
			sess->session_id, g_variant_get_uint64(data));

	ret = SRD_OK;
	for (l = sess->di_list; l; l = l->next) {
		if ((ret = srd_inst_send_meta(l->data, key, data)) != SRD_OK)
			break;
	}

	g_variant_unref(data);

	return ret;
}

/**
 * Send a chunk of logic sample data to a running decoder session.
 *
 * If no channel map has been set up, the logic samples must be arranged
 * in channel order, in the least amount of space possible. The default
 * channel set consists of all required channels + all optional channels.
 *
 * The size of a sample in inbuf is 'unitsize' bytes. If no channel map
 * has been configured, it is the minimum number of bytes needed to store
 * the default channels.
 *
 * The calls to this function must provide the samples that shall be
 * used by the protocol decoder
 *  - in the correct order ([...]5, 6, 4, 7, 8[...] is a bug),
 *  - starting from sample zero (2, 3, 4, 5, 6[...] is a bug),
 *  - consecutively, with no gaps (0, 1, 2, 4, 5[...] is a bug).
 *
 * The start- and end-sample numbers are absolute sample numbers (relative
 * to the start of the whole capture/file/stream), i.e. they are not relative
 * sample numbers within the chunk specified by 'inbuf' and 'inbuflen'.
 *
 * Correct example (4096 samples total, 4 chunks @ 1024 samples each):
 *   srd_session_send(s, 0,    1023, inbuf, 1024, 1);
 *   srd_session_send(s, 1024, 2047, inbuf, 1024, 1);
 *   srd_session_send(s, 2048, 3071, inbuf, 1024, 1);
 *   srd_session_send(s, 3072, 4095, inbuf, 1024, 1);
 *
 * The chunk size ('inbuflen') can be arbitrary and can differ between calls.
 *
 * Correct example (4096 samples total, 7 chunks @ various samples each):
 *   srd_session_send(s, 0,    1023, inbuf, 1024, 1);
 *   srd_session_send(s, 1024, 1123, inbuf,  100, 1);
 *   srd_session_send(s, 1124, 1423, inbuf,  300, 1);
 *   srd_session_send(s, 1424, 1642, inbuf,  219, 1);
 *   srd_session_send(s, 1643, 2047, inbuf,  405, 1);
 *   srd_session_send(s, 2048, 3071, inbuf, 1024, 1);
 *   srd_session_send(s, 3072, 4095, inbuf, 1024, 1);
 *
 * INCORRECT example (4096 samples total, 4 chunks @ 1024 samples each, but
 * the start- and end-samplenumbers are not absolute):
 *   srd_session_send(s, 0,    1023, inbuf, 1024, 1);
 *   srd_session_send(s, 0,    1023, inbuf, 1024, 1);
 *   srd_session_send(s, 0,    1023, inbuf, 1024, 1);
 *   srd_session_send(s, 0,    1023, inbuf, 1024, 1);
 *
 * @param sess The session to use. Must not be NULL.
 * @param abs_start_samplenum The absolute starting sample number for the
 *              buffer's sample set, relative to the start of capture.
 * @param abs_end_samplenum The absolute ending sample number for the
 *              buffer's sample set, relative to the start of capture.
 * @param inbuf Pointer to sample data. Must not be NULL.
 * @param inbuflen Length in bytes of the buffer. Must be > 0.
 * @param unitsize The number of bytes per sample. Must be > 0.
 *
 * @return SRD_OK upon success, a (negative) error code otherwise.
 *
 * @since 0.4.0
 */
SRD_API int srd_session_send(struct srd_session *sess,
		uint64_t abs_start_samplenum, uint64_t abs_end_samplenum,
		const uint8_t *inbuf, uint64_t inbuflen, uint64_t unitsize)
{
	GSList *d;
	int ret;

	if (session_is_valid(sess) != SRD_OK) {
		srd_err("Invalid session.");
		return SRD_ERR_ARG;
	}

	for (d = sess->di_list; d; d = d->next) {
		if ((ret = srd_inst_decode(d->data, abs_start_samplenum,
				abs_end_samplenum, inbuf, inbuflen, unitsize)) != SRD_OK)
			return ret;
	}

	return SRD_OK;
}

/**
 * Destroy a decoding session.
 *
 * All decoder instances and output callbacks are properly released.
 *
 * @param sess The session to be destroyed.
 *
 * @return SRD_OK upon success, a (negative) error code otherwise.
 *
 * @since 0.3.0
 */
SRD_API int srd_session_destroy(struct srd_session *sess)
{
	int session_id;

	if (!sess) {
		srd_err("Invalid session.");
		return SRD_ERR_ARG;
	}

	session_id = sess->session_id;
	if (sess->di_list)
		srd_inst_free_all(sess);
	if (sess->callbacks)
		g_slist_free_full(sess->callbacks, g_free);
	sessions = g_slist_remove(sessions, sess);
	g_free(sess);

	srd_dbg("Destroyed session %d.", session_id);

	return SRD_OK;
}

/**
 * Register/add a decoder output callback function.
 *
 * The function will be called when a protocol decoder sends output back
 * to the PD controller (except for Python objects, which only go up the
 * stack).
 *
 * @param sess The output session in which to register the callback.
 * @param output_type The output type this callback will receive. Only one
 *                    callback per output type can be registered.
 * @param cb The function to call. Must not be NULL.
 * @param cb_data Private data for the callback function. Can be NULL.
 *
 * @since 0.3.0
 */
SRD_API int srd_pd_output_callback_add(struct srd_session *sess,
		int output_type, srd_pd_output_callback cb, void *cb_data)
{
	struct srd_pd_callback *pd_cb;

	if (session_is_valid(sess) != SRD_OK) {
		srd_err("Invalid session.");
		return SRD_ERR_ARG;
	}

	srd_dbg("Registering new callback for output type %d.", output_type);

	pd_cb = g_malloc(sizeof(struct srd_pd_callback));
	pd_cb->output_type = output_type;
	pd_cb->cb = cb;
	pd_cb->cb_data = cb_data;
	sess->callbacks = g_slist_append(sess->callbacks, pd_cb);

	return SRD_OK;
}

/** @private */
SRD_PRIV struct srd_pd_callback *srd_pd_output_callback_find(
		struct srd_session *sess, int output_type)
{
	GSList *l;
	struct srd_pd_callback *tmp, *pd_cb;

	if (session_is_valid(sess) != SRD_OK) {
		srd_err("Invalid session.");
		return NULL;
	}

	pd_cb = NULL;
	for (l = sess->callbacks; l; l = l->next) {
		tmp = l->data;
		if (tmp->output_type == output_type) {
			pd_cb = tmp;
			break;
		}
	}

	return pd_cb;
}

/** @} */
Commit	Line	Data
fe9d91a8 BV	1	/*
	2	* This file is part of the libsigrokdecode project.
	3	*
	4	* Copyright (C) 2010 Uwe Hermann <uwe@hermann-uwe.de>
	5	* Copyright (C) 2013 Bert Vermeulen <bert@biot.com>
	6	*
	7	* This program is free software: you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License as published by
	9	* the Free Software Foundation, either version 3 of the License, or
	10	* (at your option) any later version.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	19	*/
	20
36784362	21	#include <config.h>
f6c7eade MC	22	#include "libsigrokdecode-internal.h" /* First, so we avoid a _POSIX_C_SOURCE warning. */
f6c7eade MC	23	#include "libsigrokdecode.h"
d95f2888	24	#include <inttypes.h>
fe9d91a8 BV	25	#include <glib.h>
	26
	27	/**
	28	* @file
	29	*
	30	* Session handling.
	31	*/
	32
	33	/**
	34	* @defgroup grp_session Session handling
	35	*
	36	* Starting and handling decoding sessions.
	37	*
	38	* @{
	39	*/
	40
	41	/** @cond PRIVATE */
	42
	43	SRD_PRIV GSList *sessions = NULL;
23a29d24	44	SRD_PRIV int max_session_id = -1;
fe9d91a8 BV	45
	46	/** @endcond */
	47
	48	/** @private */
	49	SRD_PRIV int session_is_valid(struct srd_session *sess)
	50	{
	51
	52	if (!sess \|\| sess->session_id < 1)
	53	return SRD_ERR;
	54
	55	return SRD_OK;
	56	}
	57
	58	/**
	59	* Create a decoding session.
	60	*
	61	* A session holds all decoder instances, their stack relationships and
	62	* output callbacks.
	63	*
	64	* @param sess A pointer which will hold a pointer to a newly
	65	* initialized session on return.
	66	*
	67	* @return SRD_OK upon success, a (negative) error code otherwise.
	68	*
	69	* @since 0.3.0
	70	*/
	71	SRD_API int srd_session_new(struct srd_session **sess)
	72	{
	73
	74	if (!sess) {
	75	srd_err("Invalid session pointer.");
	76	return SRD_ERR_ARG;
	77	}
	78
077fa8ac	79	*sess = g_malloc(sizeof(struct srd_session));
fe9d91a8 BV	80	(*sess)->session_id = ++max_session_id;
	81	(sess)->di_list = (sess)->callbacks = NULL;
	82
	83	/* Keep a list of all sessions, so we can clean up as needed. */
	84	sessions = g_slist_append(sessions, *sess);
	85
	86	srd_dbg("Created session %d.", (*sess)->session_id);
	87
	88	return SRD_OK;
	89	}
	90
	91	/**
	92	* Start a decoding session.
	93	*
	94	* Decoders, instances and stack must have been prepared beforehand,
	95	* and all SRD_CONF parameters set.
	96	*
	97	* @param sess The session to start.
	98	*
	99	* @return SRD_OK upon success, a (negative) error code otherwise.
	100	*
	101	* @since 0.3.0
	102	*/
	103	SRD_API int srd_session_start(struct srd_session *sess)
	104	{
	105	GSList *d;
	106	struct srd_decoder_inst *di;
	107	int ret;
	108
	109	if (session_is_valid(sess) != SRD_OK) {
	110	srd_err("Invalid session pointer.");
	111	return SRD_ERR;
	112	}
	113
	114	srd_dbg("Calling start() on all instances in session %d.", sess->session_id);
	115
	116	/* Run the start() method on all decoders receiving frontend data. */
	117	ret = SRD_OK;
	118	for (d = sess->di_list; d; d = d->next) {
	119	di = d->data;
	120	if ((ret = srd_inst_start(di)) != SRD_OK)
	121	break;
	122	}
	123
	124	return ret;
	125	}
	126
4467372a	127	static int srd_inst_send_meta(struct srd_decoder_inst *di, int key,
fe9d91a8 BV	128	GVariant *data)
	129	{
	130	PyObject *py_ret;
937e4c51 SB	131	GSList *l;
	132	struct srd_decoder_inst *next_di;
	133	int ret;
514b2edc	134	PyGILState_STATE gstate;
fe9d91a8 BV	135
	136	if (key != SRD_CONF_SAMPLERATE)
	137	/* This is the only key we pass on to the decoder for now. */
	138	return SRD_OK;
	139
514b2edc UH	140	gstate = PyGILState_Ensure();
514b2edc UH	141
937e4c51 SB	142	if (PyObject_HasAttrString(di->py_inst, "metadata")) {
	143	py_ret = PyObject_CallMethod(di->py_inst, "metadata", "lK",
	144	(long)SRD_CONF_SAMPLERATE,
	145	(unsigned long long)g_variant_get_uint64(data));
	146	Py_XDECREF(py_ret);
	147	}
fe9d91a8	148
514b2edc UH	149	PyGILState_Release(gstate);
514b2edc UH	150
937e4c51 SB	151	/* Push metadata to all the PDs stacked on top of this one. */
	152	for (l = di->next_di; l; l = l->next) {
	153	next_di = l->data;
	154	if ((ret = srd_inst_send_meta(next_di, key, data)) != SRD_OK)
	155	return ret;
	156	}
fe9d91a8 BV	157
	158	return SRD_OK;
	159	}
	160
	161	/**
	162	* Set a metadata configuration key in a session.
	163	*
	164	* @param sess The session to configure.
	165	* @param key The configuration key (SRD_CONF_*).
	166	* @param data The new value for the key, as a GVariant with GVariantType
	167	* appropriate to that key. A floating reference can be passed
	168	* in; its refcount will be sunk and unreferenced after use.
	169	*
	170	* @return SRD_OK upon success, a (negative) error code otherwise.
	171	*
	172	* @since 0.3.0
	173	*/
	174	SRD_API int srd_session_metadata_set(struct srd_session *sess, int key,
	175	GVariant *data)
	176	{
	177	GSList *l;
	178	int ret;
	179
	180	if (session_is_valid(sess) != SRD_OK) {
	181	srd_err("Invalid session.");
	182	return SRD_ERR_ARG;
	183	}
	184
ca27aa8f BV	185	if (!key) {
	186	srd_err("Invalid key.");
	187	return SRD_ERR_ARG;
	188	}
	189
	190	if (!data) {
	191	srd_err("Invalid value.");
	192	return SRD_ERR_ARG;
	193	}
	194
	195	/* Hardcoded to samplerate/uint64 for now. */
	196
fe9d91a8 BV	197	if (key != SRD_CONF_SAMPLERATE) {
	198	srd_err("Unknown config key %d.", key);
	199	return SRD_ERR_ARG;
	200	}
ca27aa8f BV	201	if (!g_variant_is_of_type(data, G_VARIANT_TYPE_UINT64)) {
	202	srd_err("Invalid value type: expected uint64, got %s",
	203	g_variant_get_type_string(data));
	204	return SRD_ERR_ARG;
	205	}
fe9d91a8	206
23e806c2	207	srd_dbg("Setting session %d samplerate to %"G_GUINT64_FORMAT".",
fe9d91a8 BV	208	sess->session_id, g_variant_get_uint64(data));
	209
	210	ret = SRD_OK;
	211	for (l = sess->di_list; l; l = l->next) {
	212	if ((ret = srd_inst_send_meta(l->data, key, data)) != SRD_OK)
	213	break;
	214	}
	215
	216	g_variant_unref(data);
	217
	218	return ret;
	219	}
	220
	221	/**
	222	* Send a chunk of logic sample data to a running decoder session.
	223	*
6a15597a UH	224	* If no channel map has been set up, the logic samples must be arranged
	225	* in channel order, in the least amount of space possible. The default
	226	* channel set consists of all required channels + all optional channels.
fe9d91a8	227	*
cda2d36c UH	228	* The size of a sample in inbuf is 'unitsize' bytes. If no channel map
	229	* has been configured, it is the minimum number of bytes needed to store
	230	* the default channels.
fe9d91a8	231	*
4564e8e5 UH	232	* The calls to this function must provide the samples that shall be
	233	* used by the protocol decoder
	234	* - in the correct order ([...]5, 6, 4, 7, 8[...] is a bug),
	235	* - starting from sample zero (2, 3, 4, 5, 6[...] is a bug),
	236	* - consecutively, with no gaps (0, 1, 2, 4, 5[...] is a bug).
	237	*
	238	* The start- and end-sample numbers are absolute sample numbers (relative
	239	* to the start of the whole capture/file/stream), i.e. they are not relative
	240	* sample numbers within the chunk specified by 'inbuf' and 'inbuflen'.
	241	*
	242	* Correct example (4096 samples total, 4 chunks @ 1024 samples each):
	243	* srd_session_send(s, 0, 1023, inbuf, 1024, 1);
	244	* srd_session_send(s, 1024, 2047, inbuf, 1024, 1);
	245	* srd_session_send(s, 2048, 3071, inbuf, 1024, 1);
	246	* srd_session_send(s, 3072, 4095, inbuf, 1024, 1);
	247	*
	248	* The chunk size ('inbuflen') can be arbitrary and can differ between calls.
	249	*
	250	* Correct example (4096 samples total, 7 chunks @ various samples each):
	251	* srd_session_send(s, 0, 1023, inbuf, 1024, 1);
	252	* srd_session_send(s, 1024, 1123, inbuf, 100, 1);
	253	* srd_session_send(s, 1124, 1423, inbuf, 300, 1);
	254	* srd_session_send(s, 1424, 1642, inbuf, 219, 1);
	255	* srd_session_send(s, 1643, 2047, inbuf, 405, 1);
	256	* srd_session_send(s, 2048, 3071, inbuf, 1024, 1);
	257	* srd_session_send(s, 3072, 4095, inbuf, 1024, 1);
	258	*
	259	* INCORRECT example (4096 samples total, 4 chunks @ 1024 samples each, but
	260	* the start- and end-samplenumbers are not absolute):
	261	* srd_session_send(s, 0, 1023, inbuf, 1024, 1);
	262	* srd_session_send(s, 0, 1023, inbuf, 1024, 1);
	263	* srd_session_send(s, 0, 1023, inbuf, 1024, 1);
	264	* srd_session_send(s, 0, 1023, inbuf, 1024, 1);
	265	*
e27347a4	266	* @param sess The session to use. Must not be NULL.
4564e8e5 UH	267	* @param abs_start_samplenum The absolute starting sample number for the
	268	* buffer's sample set, relative to the start of capture.
	269	* @param abs_end_samplenum The absolute ending sample number for the
	270	* buffer's sample set, relative to the start of capture.
e27347a4 UH	271	* @param inbuf Pointer to sample data. Must not be NULL.
	272	* @param inbuflen Length in bytes of the buffer. Must be > 0.
	273	* @param unitsize The number of bytes per sample. Must be > 0.
fe9d91a8 BV	274	*
	275	* @return SRD_OK upon success, a (negative) error code otherwise.
	276	*
cda2d36c	277	* @since 0.4.0
fe9d91a8 BV	278	*/
fe9d91a8 BV	279	SRD_API int srd_session_send(struct srd_session *sess,
4564e8e5	280	uint64_t abs_start_samplenum, uint64_t abs_end_samplenum,
cda2d36c	281	const uint8_t *inbuf, uint64_t inbuflen, uint64_t unitsize)
fe9d91a8 BV	282	{
	283	GSList *d;
	284	int ret;
	285
	286	if (session_is_valid(sess) != SRD_OK) {
	287	srd_err("Invalid session.");
	288	return SRD_ERR_ARG;
	289	}
	290
fe9d91a8	291	for (d = sess->di_list; d; d = d->next) {
4564e8e5 UH	292	if ((ret = srd_inst_decode(d->data, abs_start_samplenum,
4564e8e5 UH	293	abs_end_samplenum, inbuf, inbuflen, unitsize)) != SRD_OK)
fe9d91a8 BV	294	return ret;
	295	}
	296
	297	return SRD_OK;
	298	}
	299
	300	/**
	301	* Destroy a decoding session.
	302	*
	303	* All decoder instances and output callbacks are properly released.
	304	*
	305	* @param sess The session to be destroyed.
	306	*
	307	* @return SRD_OK upon success, a (negative) error code otherwise.
	308	*
	309	* @since 0.3.0
	310	*/
	311	SRD_API int srd_session_destroy(struct srd_session *sess)
	312	{
	313	int session_id;
	314
	315	if (!sess) {
	316	srd_err("Invalid session.");
	317	return SRD_ERR_ARG;
	318	}
	319
	320	session_id = sess->session_id;
	321	if (sess->di_list)
3262ef02	322	srd_inst_free_all(sess);
fe9d91a8 BV	323	if (sess->callbacks)
	324	g_slist_free_full(sess->callbacks, g_free);
	325	sessions = g_slist_remove(sessions, sess);
	326	g_free(sess);
	327
	328	srd_dbg("Destroyed session %d.", session_id);
	329
	330	return SRD_OK;
	331	}
	332
	333	/**
	334	* Register/add a decoder output callback function.
	335	*
	336	* The function will be called when a protocol decoder sends output back
	337	* to the PD controller (except for Python objects, which only go up the
	338	* stack).
	339	*
	340	* @param sess The output session in which to register the callback.
	341	* @param output_type The output type this callback will receive. Only one
	342	* callback per output type can be registered.
	343	* @param cb The function to call. Must not be NULL.
	344	* @param cb_data Private data for the callback function. Can be NULL.
	345	*
	346	* @since 0.3.0
	347	*/
	348	SRD_API int srd_pd_output_callback_add(struct srd_session *sess,
2372b199	349	int output_type, srd_pd_output_callback cb, void *cb_data)
fe9d91a8 BV	350	{
	351	struct srd_pd_callback *pd_cb;
	352
	353	if (session_is_valid(sess) != SRD_OK) {
	354	srd_err("Invalid session.");
	355	return SRD_ERR_ARG;
	356	}
	357
	358	srd_dbg("Registering new callback for output type %d.", output_type);
	359
077fa8ac	360	pd_cb = g_malloc(sizeof(struct srd_pd_callback));
fe9d91a8 BV	361	pd_cb->output_type = output_type;
	362	pd_cb->cb = cb;
	363	pd_cb->cb_data = cb_data;
	364	sess->callbacks = g_slist_append(sess->callbacks, pd_cb);
	365
	366	return SRD_OK;
	367	}
	368
	369	/** @private */
	370	SRD_PRIV struct srd_pd_callback *srd_pd_output_callback_find(
	371	struct srd_session *sess, int output_type)
	372	{
	373	GSList *l;
	374	struct srd_pd_callback tmp, pd_cb;
	375
	376	if (session_is_valid(sess) != SRD_OK) {
	377	srd_err("Invalid session.");
	378	return NULL;
	379	}
	380
	381	pd_cb = NULL;
	382	for (l = sess->callbacks; l; l = l->next) {
	383	tmp = l->data;
	384	if (tmp->output_type == output_type) {
	385	pd_cb = tmp;
	386	break;
	387	}
	388	}
	389
	390	return pd_cb;
	391	}
	392
	393	/** @} */