X-Git-Url: https://sigrok.org/gitweb/?p=libsigrokdecode.git;a=blobdiff_plain;f=instance.c;h=6fbdc01fe7e888c57b43e9ad2a3af6cd5dd2788a;hp=e80afd751469b7fb6d81acac51cdff3591131019;hb=9553e9622bb26dfbe6296ef6f330b1cf0f5b40e6;hpb=f98f41714fc5c7516f614e0d453f6226533d981d

diff --git a/instance.c b/instance.c
index e80afd7..6fbdc01 100644
--- a/instance.c
+++ b/instance.c
@@ -30,8 +30,10 @@
 
 extern SRD_PRIV GSList *sessions;
 
-/* module_sigrokdecode.c */
-extern SRD_PRIV PyObject *srd_logic_type;
+static void srd_inst_join_decode_thread(struct srd_decoder_inst *di);
+static void srd_inst_reset_state(struct srd_decoder_inst *di);
+SRD_PRIV void oldpins_array_seed(struct srd_decoder_inst *di);
+SRD_PRIV void oldpins_array_free(struct srd_decoder_inst *di);
 
 /** @endcond */
 
@@ -72,6 +74,7 @@ SRD_API int srd_inst_option_set(struct srd_decoder_inst *di,
 	gint64 val_int;
 	int ret;
 	const char *val_str;
+	PyGILState_STATE gstate;
 
 	if (!di) {
 		srd_err("Invalid decoder instance.");
@@ -83,8 +86,11 @@ SRD_API int srd_inst_option_set(struct srd_decoder_inst *di,
 		return SRD_ERR_ARG;
 	}
 
+	gstate = PyGILState_Ensure();
+
 	if (!PyObject_HasAttrString(di->decoder->py_dec, "options")) {
 		/* Decoder has no options. */
+		PyGILState_Release(gstate);
 		if (g_hash_table_size(options) == 0) {
 			/* No options provided. */
 			return SRD_OK;
@@ -166,6 +172,7 @@ err_out:
 		srd_exception_catch("Stray exception in srd_inst_option_set()");
 		ret = SRD_ERR_PYTHON;
 	}
+	PyGILState_Release(gstate);
 
 	return ret;
 }
@@ -249,14 +256,20 @@ SRD_API int srd_inst_channel_set_all(struct srd_decoder_inst *di,
 		}
 		pdch = sl->data;
 		new_channelmap[pdch->order] = new_channelnum;
-		srd_dbg("Setting channel mapping: %s (index %d) = channel %d.",
+		srd_dbg("Setting channel mapping: %s (PD ch idx %d) = input data ch idx %d.",
 			pdch->id, pdch->order, new_channelnum);
 	}
 
 	srd_dbg("Final channel map:");
 	num_required_channels = g_slist_length(di->decoder->channels);
 	for (i = 0; i < di->dec_num_channels; i++) {
-		srd_dbg(" - index %d = channel %d (%s)", i, new_channelmap[i],
+		GSList *l = g_slist_nth(di->decoder->channels, i);
+		if (!l)
+			l = g_slist_nth(di->decoder->opt_channels,
+				i - num_required_channels);
+		pdch = l->data;
+		srd_dbg(" - PD ch idx %d (%s) = input data ch idx %d (%s)", i,
+			pdch->id, new_channelmap[i],
 			(i < num_required_channels) ? "required" : "optional");
 	}
 
@@ -296,6 +309,7 @@ SRD_API struct srd_decoder_inst *srd_inst_new(struct srd_session *sess,
 	struct srd_decoder *dec;
 	struct srd_decoder_inst *di;
 	char *inst_id;
+	PyGILState_STATE gstate;
 
 	i = 1;
 	srd_dbg("Creating new %s instance.", decoder_id);
@@ -349,16 +363,24 @@ SRD_API struct srd_decoder_inst *srd_inst_new(struct srd_session *sess,
 		di->channel_samples = g_malloc(di->dec_num_channels);
 	}
 
+	/* Default to the initial pins being the same as in sample 0. */
+	oldpins_array_seed(di);
+
+	gstate = PyGILState_Ensure();
+
 	/* Create a new instance of this decoder class. */
 	if (!(di->py_inst = PyObject_CallObject(dec->py_dec, NULL))) {
 		if (PyErr_Occurred())
 			srd_exception_catch("Failed to create %s instance",
 					decoder_id);
+		PyGILState_Release(gstate);
 		g_free(di->dec_channelmap);
 		g_free(di);
 		return NULL;
 	}
 
+	PyGILState_Release(gstate);
+
 	if (options && srd_inst_option_set(di, options) != SRD_OK) {
 		g_free(di->dec_channelmap);
 		g_free(di);
@@ -372,10 +394,20 @@ SRD_API struct srd_decoder_inst *srd_inst_new(struct srd_session *sess,
 	di->inbuf = NULL;
 	di->inbuflen = 0;
 	di->abs_cur_samplenum = 0;
-	di->old_pins_array = NULL;
 	di->thread_handle = NULL;
 	di->got_new_samples = FALSE;
 	di->handled_all_samples = FALSE;
+	di->want_wait_terminate = FALSE;
+
+	/*
+	 * Strictly speaking initialization of statically allocated
+	 * condition and mutex variables (or variables allocated on the
+	 * stack) is not required, but won't harm either. Explicitly
+	 * running init() will better match subsequent clear() calls.
+	 */
+	g_cond_init(&di->got_new_samples_cond);
+	g_cond_init(&di->handled_all_samples_cond);
+	g_mutex_init(&di->data_mutex);
 
 	/* Instance takes input from a frontend by default. */
 	sess->di_list = g_slist_append(sess->di_list, di);
@@ -384,6 +416,66 @@ SRD_API struct srd_decoder_inst *srd_inst_new(struct srd_session *sess,
 	return di;
 }
 
+static void srd_inst_join_decode_thread(struct srd_decoder_inst *di)
+{
+	if (!di)
+		return;
+	if (!di->thread_handle)
+		return;
+
+	srd_dbg("%s: Joining decoder thread.", di->inst_id);
+
+	/*
+	 * Terminate potentially running threads which still
+	 * execute the decoder instance's decode() method.
+	 */
+	srd_dbg("%s: Raising want_term, sending got_new.", di->inst_id);
+	g_mutex_lock(&di->data_mutex);
+	di->want_wait_terminate = TRUE;
+	g_cond_signal(&di->got_new_samples_cond);
+	g_mutex_unlock(&di->data_mutex);
+
+	srd_dbg("%s: Running join().", di->inst_id);
+	(void)g_thread_join(di->thread_handle);
+	srd_dbg("%s: Call to join() done.", di->inst_id);
+	di->thread_handle = NULL;
+
+	/*
+	 * Reset condition and mutex variables, such that next
+	 * operations on them will find them in a clean state.
+	 */
+	g_cond_clear(&di->got_new_samples_cond);
+	g_cond_init(&di->got_new_samples_cond);
+	g_cond_clear(&di->handled_all_samples_cond);
+	g_cond_init(&di->handled_all_samples_cond);
+	g_mutex_clear(&di->data_mutex);
+	g_mutex_init(&di->data_mutex);
+}
+
+static void srd_inst_reset_state(struct srd_decoder_inst *di)
+{
+	if (!di)
+		return;
+
+	srd_dbg("%s: Resetting decoder state.", di->inst_id);
+
+	/*
+	 * Reset internal state of the decoder.
+	 */
+	condition_list_free(di);
+	match_array_free(di);
+	di->abs_start_samplenum = 0;
+	di->abs_end_samplenum = 0;
+	di->inbuf = NULL;
+	di->inbuflen = 0;
+	di->abs_cur_samplenum = 0;
+	oldpins_array_free(di);
+	di->got_new_samples = FALSE;
+	di->handled_all_samples = FALSE;
+	di->want_wait_terminate = FALSE;
+	/* Conditions and mutex got reset after joining the thread. */
+}
+
 /**
  * Stack a decoder instance on top of another.
  *
@@ -399,7 +491,6 @@ SRD_API int srd_inst_stack(struct srd_session *sess,
 		struct srd_decoder_inst *di_bottom,
 		struct srd_decoder_inst *di_top)
 {
-
 	if (session_is_valid(sess) != SRD_OK) {
 		srd_err("Invalid session.");
 		return SRD_ERR_ARG;
@@ -550,51 +641,83 @@ SRD_PRIV struct srd_decoder_inst *srd_inst_find_by_obj(const GSList *stack,
 /**
  * Set the list of initial (assumed) pin values.
  *
- * If the list already exists, do nothing.
- *
  * @param di Decoder instance to use. Must not be NULL.
+ * @param initial_pins A GArray of uint8_t values. Must not be NULL.
  *
- * @private
+ * @since 0.5.0
  */
-static void set_initial_pin_values(struct srd_decoder_inst *di)
+SRD_API int srd_inst_initial_pins_set_all(struct srd_decoder_inst *di, GArray *initial_pins)
 {
 	int i;
 	GString *s;
-	PyObject *py_initial_pins;
 
-	if (!di || !di->py_inst) {
+	if (!di) {
 		srd_err("Invalid decoder instance.");
-		return;
-	}
-
-	/* Nothing to do if di->old_pins_array is already != NULL. */
-	if (di->old_pins_array) {
-		srd_dbg("Initial pins already set, nothing to do.");
-		return;
+		return SRD_ERR_ARG;
 	}
 
-	/* Create an array of old (previous sample) pins, init to 0. */
-	di->old_pins_array = g_array_sized_new(FALSE, TRUE, sizeof(uint8_t), di->dec_num_channels);
-	g_array_set_size(di->old_pins_array, di->dec_num_channels);
+	if (!initial_pins)
+		return SRD_ERR_ARG;
 
-	/* Check if the decoder has set self.initial_pins. */
-	if (!PyObject_HasAttrString(di->py_inst, "initial_pins")) {
-		srd_dbg("Initial pins: all 0 (self.initial_pins not set).");
-		return;
+	if (initial_pins->len != (guint)di->dec_num_channels) {
+		srd_err("Incorrect number of channels (need %d, got %d).",
+			di->dec_num_channels, initial_pins->len);
+		return SRD_ERR_ARG;
 	}
 
-	/* Get self.initial_pins. */
-	py_initial_pins = PyObject_GetAttrString(di->py_inst, "initial_pins");
+	/* Sanity-check initial pin state values. */
+	for (i = 0; i < di->dec_num_channels; i++) {
+		if (initial_pins->data[i] <= 2)
+			continue;
+		srd_err("Invalid initial channel %d pin state: %d.",
+			i, initial_pins->data[i]);
+		return SRD_ERR_ARG;
+	}
 
-	/* Fill di->old_pins_array based on self.initial_pins. */
 	s = g_string_sized_new(100);
+	oldpins_array_seed(di);
 	for (i = 0; i < di->dec_num_channels; i++) {
-		di->old_pins_array->data[i] = PyLong_AsLong(PyList_GetItem(py_initial_pins, i));
+		di->old_pins_array->data[i] = initial_pins->data[i];
 		g_string_append_printf(s, "%d, ", di->old_pins_array->data[i]);
 	}
 	s = g_string_truncate(s, s->len - 2);
 	srd_dbg("Initial pins: %s.", s->str);
 	g_string_free(s, TRUE);
+
+	return SRD_OK;
+}
+
+/** @private */
+SRD_PRIV void oldpins_array_seed(struct srd_decoder_inst *di)
+{
+	size_t count;
+	GArray *arr;
+
+	if (!di)
+		return;
+	if (di->old_pins_array)
+		return;
+
+	srd_dbg("%s: Seeding old pins, %s().", di->inst_id, __func__);
+	count = di->dec_num_channels;
+	arr = g_array_sized_new(FALSE, TRUE, sizeof(uint8_t), count);
+	g_array_set_size(arr, count);
+	memset(arr->data, SRD_INITIAL_PIN_SAME_AS_SAMPLE0, count);
+	di->old_pins_array = arr;
+}
+
+/** @private */
+SRD_PRIV void oldpins_array_free(struct srd_decoder_inst *di)
+{
+	if (!di)
+		return;
+	if (!di->old_pins_array)
+		return;
+
+	srd_dbg("%s: Releasing initial pin state.", di->inst_id);
+
+	g_array_free(di->old_pins_array, TRUE);
+	di->old_pins_array = NULL;
 }
 
 /** @private */
@@ -604,27 +727,30 @@ SRD_PRIV int srd_inst_start(struct srd_decoder_inst *di)
 	GSList *l;
 	struct srd_decoder_inst *next_di;
 	int ret;
+	PyGILState_STATE gstate;
 
 	srd_dbg("Calling start() method on protocol decoder instance %s.",
 			di->inst_id);
 
+	gstate = PyGILState_Ensure();
+
 	/* Run self.start(). */
 	if (!(py_res = PyObject_CallMethod(di->py_inst, "start", NULL))) {
 		srd_exception_catch("Protocol decoder instance %s",
 				di->inst_id);
+		PyGILState_Release(gstate);
 		return SRD_ERR_PYTHON;
 	}
 	Py_DecRef(py_res);
 
-	/* Set the initial pins based on self.initial_pins. */
-	set_initial_pin_values(di);
-
 	/* Set self.samplenum to 0. */
 	PyObject_SetAttrString(di->py_inst, "samplenum", PyLong_FromLong(0));
 
 	/* Set self.matched to None. */
 	PyObject_SetAttrString(di->py_inst, "matched", Py_None);
 
+	PyGILState_Release(gstate);
+
 	/* Start all the PDs stacked on top of this one. */
 	for (l = di->next_di; l; l = l->next) {
 		next_di = l->data;
@@ -653,8 +779,7 @@ SRD_PRIV int srd_inst_start(struct srd_decoder_inst *di)
  */
 static gboolean sample_matches(uint8_t old_sample, uint8_t sample, struct srd_term *term)
 {
-	if (!term)
-		return FALSE;
+	/* Caller ensures term != NULL. */
 
 	switch (term->type) {
 	case SRD_TERM_HIGH:
@@ -694,6 +819,7 @@ static gboolean sample_matches(uint8_t old_sample, uint8_t sample, struct srd_te
 	return FALSE;
 }
 
+/** @private */
 SRD_PRIV void match_array_free(struct srd_decoder_inst *di)
 {
 	if (!di || !di->match_array)
@@ -703,6 +829,7 @@ SRD_PRIV void match_array_free(struct srd_decoder_inst *di)
 	di->match_array = NULL;
 }
 
+/** @private */
 SRD_PRIV void condition_list_free(struct srd_decoder_inst *di)
 {
 	GSList *l, *ll;
@@ -744,6 +871,7 @@ static void update_old_pins_array(struct srd_decoder_inst *di,
 	if (!di || !di->dec_channelmap || !sample_pos)
 		return;
 
+	oldpins_array_seed(di);
 	for (i = 0; i < di->dec_num_channels; i++) {
 		byte_offset = di->dec_channelmap[i] / 8;
 		bit_offset = di->dec_channelmap[i] % 8;
@@ -752,25 +880,44 @@ static void update_old_pins_array(struct srd_decoder_inst *di,
 	}
 }
 
+static void update_old_pins_array_initial_pins(struct srd_decoder_inst *di)
+{
+	uint8_t sample;
+	int i, byte_offset, bit_offset;
+	const uint8_t *sample_pos;
+
+	if (!di || !di->dec_channelmap)
+		return;
+
+	sample_pos = di->inbuf + ((di->abs_cur_samplenum - di->abs_start_samplenum) * di->data_unitsize);
+
+	oldpins_array_seed(di);
+	for (i = 0; i < di->dec_num_channels; i++) {
+		if (di->old_pins_array->data[i] != SRD_INITIAL_PIN_SAME_AS_SAMPLE0)
+			continue;
+		byte_offset = di->dec_channelmap[i] / 8;
+		bit_offset = di->dec_channelmap[i] % 8;
+		sample = *(sample_pos + byte_offset) & (1 << bit_offset) ? 1 : 0;
+		di->old_pins_array->data[i] = sample;
+	}
+}
+
 static gboolean term_matches(const struct srd_decoder_inst *di,
 		struct srd_term *term, const uint8_t *sample_pos)
 {
 	uint8_t old_sample, sample;
 	int byte_offset, bit_offset, ch;
 
-	if (!di || !di->dec_channelmap || !term || !sample_pos)
-		return FALSE;
+	/* Caller ensures di, di->dec_channelmap, term, sample_pos != NULL. */
 
-	/* Overwritten below (or ignored for SRD_TERM_SKIP). */
-	old_sample = sample = 0;
+	if (term->type == SRD_TERM_SKIP)
+		return sample_matches(0, 0, term);
 
-	if (term->type != SRD_TERM_SKIP) {
-		ch = term->channel;
-		byte_offset = di->dec_channelmap[ch] / 8;
-		bit_offset = di->dec_channelmap[ch] % 8;
-		sample = *(sample_pos + byte_offset) & (1 << bit_offset) ? 1 : 0;
-		old_sample = di->old_pins_array->data[ch];
-	}
+	ch = term->channel;
+	byte_offset = di->dec_channelmap[ch] / 8;
+	bit_offset = di->dec_channelmap[ch] % 8;
+	sample = *(sample_pos + byte_offset) & (1 << bit_offset) ? 1 : 0;
+	old_sample = di->old_pins_array->data[ch];
 
 	return sample_matches(old_sample, sample, term);
 }
@@ -781,8 +928,7 @@ static gboolean all_terms_match(const struct srd_decoder_inst *di,
 	const GSList *l;
 	struct srd_term *term;
 
-	if (!di || !cond || !sample_pos)
-		return FALSE;
+	/* Caller ensures di, cond, sample_pos != NULL. */
 
 	for (l = cond; l; l = l->next) {
 		term = l->data;
@@ -798,8 +944,7 @@ static gboolean at_least_one_condition_matched(
 {
 	unsigned int i;
 
-	if (!di)
-		return FALSE;
+	/* Caller ensures di != NULL. */
 
 	for (i = 0; i < num_conditions; i++) {
 		if (di->match_array->data[i])
@@ -811,12 +956,13 @@ static gboolean at_least_one_condition_matched(
 
 static gboolean find_match(struct srd_decoder_inst *di)
 {
-	static uint64_t s = 0;
 	uint64_t i, j, num_samples_to_process;
 	GSList *l, *cond;
 	const uint8_t *sample_pos;
 	unsigned int num_conditions;
 
+	/* Caller ensures di != NULL. */
+
 	/* Check whether the condition list is NULL/empty. */
 	if (!di->condition_list) {
 		srd_dbg("NULL/empty condition list, automatic match.");
@@ -836,7 +982,11 @@ static gboolean find_match(struct srd_decoder_inst *di)
 	di->match_array = g_array_sized_new(FALSE, TRUE, sizeof(gboolean), num_conditions);
 	g_array_set_size(di->match_array, num_conditions);
 
-	for (i = 0, s = 0; i < num_samples_to_process; i++, s++, (di->abs_cur_samplenum)++) {
+	/* Sample 0: Set di->old_pins_array for SRD_INITIAL_PIN_SAME_AS_SAMPLE0 pins. */
+	if (di->abs_cur_samplenum == 0)
+		update_old_pins_array_initial_pins(di);
+
+	for (i = 0; i < num_samples_to_process; i++, (di->abs_cur_samplenum)++) {
 
 		sample_pos = di->inbuf + ((di->abs_cur_samplenum - di->abs_start_samplenum) * di->data_unitsize);
 
@@ -865,6 +1015,8 @@ static gboolean find_match(struct srd_decoder_inst *di)
  *
  * This function returns if there is an error, or when a match is found, or
  * when all samples have been processed (whether a match was found or not).
+ * This function immediately terminates when the decoder's wait() method
+ * invocation shall get terminated.
  *
  * @param di The decoder instance to use. Must not be NULL.
  * @param found_match Will be set to TRUE if at least one condition matched,
@@ -880,6 +1032,10 @@ SRD_PRIV int process_samples_until_condition_match(struct srd_decoder_inst *di,
 	if (!di || !found_match)
 		return SRD_ERR_ARG;
 
+	*found_match = FALSE;
+	if (di->want_wait_terminate)
+		return SRD_OK;
+
 	/* Check if any of the current condition(s) match. */
 	while (TRUE) {
 		/* Feed the (next chunk of the) buffer to find_match(). */
@@ -916,20 +1072,81 @@ static gpointer di_thread(gpointer data)
 {
 	PyObject *py_res;
 	struct srd_decoder_inst *di;
+	int wanted_term;
+	PyGILState_STATE gstate;
 
 	if (!data)
 		return NULL;
 
 	di = data;
 
-	/* Call self.decode(). Only returns if the PD throws an exception. */
+	srd_dbg("%s: Starting thread routine for decoder.", di->inst_id);
+
+	gstate = PyGILState_Ensure();
+
+	/*
+	 * Call self.decode(). Only returns if the PD throws an exception.
+	 * "Regular" termination of the decode() method is not expected.
+	 */
 	Py_IncRef(di->py_inst);
-	if (!(py_res = PyObject_CallMethod(di->py_inst, "decode", NULL))) {
+	srd_dbg("%s: Calling decode() method.", di->inst_id);
+	py_res = PyObject_CallMethod(di->py_inst, "decode", NULL);
+	srd_dbg("%s: decode() method terminated.", di->inst_id);
+
+	/*
+	 * Make sure to unblock potentially pending srd_inst_decode()
+	 * calls in application threads after the decode() method might
+	 * have terminated, while it neither has processed sample data
+	 * nor has terminated upon request. This happens e.g. when "need
+	 * a samplerate to decode" exception is thrown.
+	 */
+	g_mutex_lock(&di->data_mutex);
+	wanted_term = di->want_wait_terminate;
+	di->want_wait_terminate = TRUE;
+	di->handled_all_samples = TRUE;
+	g_cond_signal(&di->handled_all_samples_cond);
+	g_mutex_unlock(&di->data_mutex);
+
+	/*
+	 * Check for the termination cause of the decode() method.
+	 * Though this is mostly for information.
+	 */
+	if (!py_res && wanted_term) {
+		/*
+		 * Silently ignore errors upon return from decode() calls
+		 * when termination was requested. Terminate the thread
+		 * which executed this instance's decode() logic.
+		 */
+		srd_dbg("%s: Thread done (!res, want_term).", di->inst_id);
+		PyErr_Clear();
+		PyGILState_Release(gstate);
+		return NULL;
+	}
+	if (!py_res) {
+		/*
+		 * The decode() invocation terminated unexpectedly. Have
+		 * the back trace printed, and terminate the thread which
+		 * executed the decode() method.
+		 */
+		srd_dbg("%s: decode() terminated unrequested.", di->inst_id);
 		srd_exception_catch("Protocol decoder instance %s: ", di->inst_id);
-		exit(1); /* TODO: Proper shutdown. This is a hack. */
+		srd_dbg("%s: Thread done (!res, !want_term).", di->inst_id);
+		PyGILState_Release(gstate);
 		return NULL;
 	}
+
+	/*
+	 * TODO: By design the decode() method is not supposed to terminate.
+	 * Nevertheless we have the thread joined, and srd backend calls to
+	 * decode() will re-start another thread transparently.
+	 */
+	srd_dbg("%s: decode() terminated (req %d).", di->inst_id, wanted_term);
 	Py_DecRef(py_res);
+	PyErr_Clear();
+
+	PyGILState_Release(gstate);
+
+	srd_dbg("%s: Thread done (with res).", di->inst_id);
 
 	return NULL;
 }
@@ -988,10 +1205,6 @@ SRD_PRIV int srd_inst_decode(struct srd_decoder_inst *di,
 		uint64_t abs_start_samplenum, uint64_t abs_end_samplenum,
 		const uint8_t *inbuf, uint64_t inbuflen, uint64_t unitsize)
 {
-	PyObject *py_res;
-	srd_logic *logic;
-	long apiver;
-
 	/* Return an error upon unusable input. */
 	if (!di) {
 		srd_dbg("empty decoder instance");
@@ -1026,56 +1239,96 @@ SRD_PRIV int srd_inst_decode(struct srd_decoder_inst *di,
 		abs_end_samplenum - abs_start_samplenum, inbuflen, di->data_unitsize,
 		di->inst_id);
 
-	apiver = srd_decoder_apiver(di->decoder);
+	/* If this is the first call, start the worker thread. */
+	if (!di->thread_handle) {
+		srd_dbg("No worker thread for this decoder stack "
+			"exists yet, creating one: %s.", di->inst_id);
+		di->thread_handle = g_thread_new(di->inst_id,
+						 di_thread, di);
+	}
 
-	if (apiver == 2) {
-		/*
-		 * Create new srd_logic object. Each iteration around the PD's
-		 * loop will fill one sample into this object.
-		 */
-		logic = PyObject_New(srd_logic, (PyTypeObject *)srd_logic_type);
-		Py_INCREF(logic);
-		logic->di = (struct srd_decoder_inst *)di;
-		logic->abs_start_samplenum = abs_start_samplenum;
-		logic->itercnt = 0;
-		logic->inbuf = (uint8_t *)inbuf;
-		logic->inbuflen = inbuflen;
-		logic->sample = PyList_New(2);
-		Py_INCREF(logic->sample);
-
-		Py_IncRef(di->py_inst);
-		if (!(py_res = PyObject_CallMethod(di->py_inst, "decode",
-			"KKO", abs_start_samplenum, abs_end_samplenum, logic))) {
-			srd_exception_catch("Protocol decoder instance %s",
-					di->inst_id);
-			return SRD_ERR_PYTHON;
-		}
-		di->abs_cur_samplenum = abs_end_samplenum;
-		Py_DecRef(py_res);
-	} else {
-		/* If this is the first call, start the worker thread. */
-		if (!di->thread_handle)
-			di->thread_handle = g_thread_new("di_thread",
-							 di_thread, di);
-
-		/* Push the new sample chunk to the worker thread. */
-		g_mutex_lock(&di->data_mutex);
-		di->abs_start_samplenum = abs_start_samplenum;
-		di->abs_end_samplenum = abs_end_samplenum;
-		di->inbuf = inbuf;
-		di->inbuflen = inbuflen;
-		di->got_new_samples = TRUE;
-		di->handled_all_samples = FALSE;
-
-		/* Signal the thread that we have new data. */
-		g_cond_signal(&di->got_new_samples_cond);
-		g_mutex_unlock(&di->data_mutex);
-
-		/* When all samples in this chunk were handled, return. */
-		g_mutex_lock(&di->data_mutex);
-		while (!di->handled_all_samples)
-			g_cond_wait(&di->handled_all_samples_cond, &di->data_mutex);
-		g_mutex_unlock(&di->data_mutex);
+	/* Push the new sample chunk to the worker thread. */
+	g_mutex_lock(&di->data_mutex);
+	di->abs_start_samplenum = abs_start_samplenum;
+	di->abs_end_samplenum = abs_end_samplenum;
+	di->inbuf = inbuf;
+	di->inbuflen = inbuflen;
+	di->got_new_samples = TRUE;
+	di->handled_all_samples = FALSE;
+	di->want_wait_terminate = FALSE;
+
+	/* Signal the thread that we have new data. */
+	g_cond_signal(&di->got_new_samples_cond);
+	g_mutex_unlock(&di->data_mutex);
+
+	/* When all samples in this chunk were handled, return. */
+	g_mutex_lock(&di->data_mutex);
+	while (!di->handled_all_samples && !di->want_wait_terminate)
+		g_cond_wait(&di->handled_all_samples_cond, &di->data_mutex);
+	g_mutex_unlock(&di->data_mutex);
+
+	return SRD_OK;
+}
+
+/**
+ * Terminate current decoder work, prepare for re-use on new input data.
+ *
+ * Terminates all decoder operations in the specified decoder instance
+ * and the instances stacked on top of it. Resets internal state such
+ * that the previously constructed stack can process new input data that
+ * is not related to previously processed input data. This avoids the
+ * expensive and complex re-construction of decoder stacks.
+ *
+ * Callers are expected to follow up with start, metadata, and decode
+ * calls like they would for newly constructed decoder stacks.
+ *
+ * @param di The decoder instance to call. Must not be NULL.
+ * @return SRD_OK upon success, a (negative) error code otherwise.
+ * @private
+ */
+SRD_PRIV int srd_inst_terminate_reset(struct srd_decoder_inst *di)
+{
+	PyGILState_STATE gstate;
+	PyObject *py_ret;
+	GSList *l;
+	int ret;
+
+	if (!di)
+		return SRD_ERR_ARG;
+
+	/*
+	 * Request termination and wait for previously initiated
+	 * background operation to finish. Reset internal state, but
+	 * do not start releasing resources yet. This shall result in
+	 * decoders' state just like after creation. This block handles
+	 * the C language library side.
+	 */
+	srd_dbg("Terminating instance %s", di->inst_id);
+	srd_inst_join_decode_thread(di);
+	srd_inst_reset_state(di);
+
+	/*
+	 * Have the Python side's .reset() method executed (if the PD
+	 * implements it). It's assumed that .reset() assigns variables
+	 * very much like __init__() used to do in the past. Thus memory
+	 * that was allocated in previous calls gets released by Python
+	 * as it's not referenced any longer.
+	 */
+	gstate = PyGILState_Ensure();
+	if (PyObject_HasAttrString(di->py_inst, "reset")) {
+		srd_dbg("Calling .reset() of instance %s", di->inst_id);
+		py_ret = PyObject_CallMethod(di->py_inst, "reset", NULL);
+		Py_XDECREF(py_ret);
+	}
+	PyGILState_Release(gstate);
+
+	/*
+	 * Pass the "restart" request to all stacked decoders.
+	 */
+	for (l = di->next_di; l; l = l->next) {
+		ret = srd_inst_terminate_reset(l->data);
+		if (ret != SRD_OK)
+			return ret;
 	}
 
 	return SRD_OK;
@@ -1086,10 +1339,18 @@ SRD_PRIV void srd_inst_free(struct srd_decoder_inst *di)
 {
 	GSList *l;
 	struct srd_pd_output *pdo;
+	PyGILState_STATE gstate;
 
 	srd_dbg("Freeing instance %s", di->inst_id);
 
+	srd_inst_join_decode_thread(di);
+
+	srd_inst_reset_state(di);
+
+	gstate = PyGILState_Ensure();
 	Py_DecRef(di->py_inst);
+	PyGILState_Release(gstate);
+
 	g_free(di->inst_id);
 	g_free(di->dec_channelmap);
 	g_free(di->channel_samples);