X-Git-Url: https://sigrok.org/gitweb/?p=libsigrokdecode.git;a=blobdiff_plain;f=controller.c;h=e325e0a6208cf98248101673c0c9714c27ffdfc0;hp=f7ffb2567ca9cee480d8047bcc4daafd45947b8f;hb=7a1712c4fd07f64222079acd5ec3fa3348a5cb15;hpb=983cb0f5b49167328864d0878148a7407becd1c0

diff --git a/controller.c b/controller.c
index f7ffb25..e325e0a 100644
--- a/controller.c
+++ b/controller.c
@@ -18,25 +18,22 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include "config.h"
 #include "sigrokdecode.h" /* First, so we avoid a _POSIX_C_SOURCE warning. */
+#include "sigrokdecode-internal.h"
+#include "config.h"
 #include <glib.h>
 #include <inttypes.h>
+#include <stdlib.h>
 
 
-static GSList *callbacks = NULL;
+/* List of decoder instances. */
+static GSList *di_list = NULL;
 
-/* TODO
-static GSList *pipelines = NULL;
-struct srd_pipeline {
-	int id;
-	GSList *decoders;
-};
-*/
+/* List of frontend callbacks to receive PD output. */
+static GSList *callbacks = NULL;
 
 /* lives in decoder.c */
 extern GSList *pd_list;
-extern GSList *di_list;
 
 /* lives in module_sigrokdecode.c */
 extern PyMODINIT_FUNC PyInit_sigrokdecode(void);
@@ -59,7 +56,7 @@ extern PyTypeObject srd_logic_type;
  * The caller is responsible for calling the clean-up function srd_exit(),
  * which will properly shut down libsigrokdecode and free its allocated memory.
  *
- * Multiple calls to srd_init(), without calling srd_exit() inbetween,
+ * Multiple calls to srd_init(), without calling srd_exit() in between,
  * are not allowed.
  *
  * @return SRD_OK upon success, a (negative) error code otherwise.
@@ -71,9 +68,12 @@ int srd_init(void)
 {
 	int ret;
 
+	srd_dbg("Initializing libsigrokdecode.");
+
+	/* Add our own module to the list of built-in modules. */
 	PyImport_AppendInittab("sigrokdecode", PyInit_sigrokdecode);
 
-	/* Py_Initialize() returns void and usually cannot fail. */
+	/* Initialize the python interpreter. */
 	Py_Initialize();
 
 	if ((ret = set_modulepath()) != SRD_OK) {
@@ -98,14 +98,15 @@ int srd_init(void)
  *
  * This function should only be called if there was a (successful!) invocation
  * of srd_init() before. Calling this function multiple times in a row, without
- * any successful srd_init() calls inbetween, is not allowed.
+ * any successful srd_init() calls in between, is not allowed.
  *
  * @return SRD_OK upon success, a (negative) error code otherwise.
  */
 int srd_exit(void)
 {
-	/* Unload/free all decoders, and then the list of decoders itself. */
-	/* TODO: Error handling. */
+
+	srd_dbg("Exiting libsigrokdecode.");
+
 	srd_unload_all_decoders();
 	g_slist_free(pd_list);
 
@@ -117,221 +118,544 @@ int srd_exit(void)
 
 
 /**
- * Add search directories for the protocol decoders.
+ * Add an additional search directory for the protocol decoders.
+ *
+ * The specified directory is prepended (not appended!) to Python's sys.path,
+ * in order to search for sigrok protocol decoders in the specified
+ * directories first, and in the generic Python module directories (and in
+ * the current working directory) last. This avoids conflicts if there are
+ * Python modules which have the same name as a sigrok protocol decoder in
+ * sys.path or in the current working directory.
  *
  * TODO: add path from env var SIGROKDECODE_PATH, config etc
+ * TODO: Should take directoryname/path as input.
+ *
+ * @return TODO.
  */
 int set_modulepath(void)
 {
 	int ret;
+	gchar *path, *s;
+
+#ifdef _WIN32
+	gchar **splitted;
+
+	/*
+	 * On Windows/MinGW, Python's sys.path needs entries of the form
+	 * 'C:\\foo\\bar' instead of '/foo/bar'.
+	 */
+
+	splitted = g_strsplit(DECODERS_DIR, "/", 0);
+	path = g_build_pathv("\\\\", splitted);
+	g_strfreev(splitted);
+#else
+	path = g_strdup(DECODERS_DIR);
+#endif
+
+	/* TODO: Sanity check on 'path' (length, escape special chars, ...). */
+	s = g_strdup_printf("import sys; sys.path.insert(0, r'%s')", path);
+
+	ret = PyRun_SimpleString(s);
+
+	g_free(path);
+	g_free(s);
+
+	return ret;
+}
+
+
+/**
+ * Set options in a decoder instance.
+ *
+ * @param di Decoder instance.
+ * @param options A GHashTable of options to set.
+ *
+ * Handled options are removed from the hash.
+ *
+ * @return SRD_OK upon success, a (negative) error code otherwise.
+ */
+int srd_instance_set_options(struct srd_decoder_instance *di,
+		GHashTable *options)
+{
+	PyObject *py_dec_options, *py_dec_optkeys, *py_di_options, *py_optval;
+	PyObject *py_optlist, *py_classval;
+	Py_UNICODE *py_ustr;
+	unsigned long long int val_ull;
+	int num_optkeys, ret, size, i;
+	char *key, *value;
+
+	if(!PyObject_HasAttrString(di->decoder->py_dec, "options")) {
+		/* Decoder has no options. */
+		if (g_hash_table_size(options) == 0) {
+			/* No options provided. */
+			return SRD_OK;
+		} else {
+			srd_err("Protocol decoder has no options.");
+			return SRD_ERR_ARG;
+		}
+		return SRD_OK;
+	}
+
+	ret = SRD_ERR_PYTHON;
+	key = NULL;
+	py_dec_options = py_dec_optkeys = py_di_options = py_optval = NULL;
+	py_optlist = py_classval = NULL;
+	py_dec_options = PyObject_GetAttrString(di->decoder->py_dec, "options");
+
+	/* All of these are synthesized objects, so they're good. */
+	py_dec_optkeys = PyDict_Keys(py_dec_options);
+	num_optkeys = PyList_Size(py_dec_optkeys);
+	if (!(py_di_options = PyObject_GetAttrString(di->py_instance, "options")))
+		goto err_out;
+	for (i = 0; i < num_optkeys; i++) {
+		/* Get the default class value for this option. */
+		py_str_as_str(PyList_GetItem(py_dec_optkeys, i), &key);
+		if (!(py_optlist = PyDict_GetItemString(py_dec_options, key)))
+			goto err_out;
+		if (!(py_classval = PyList_GetItem(py_optlist, 1)))
+			goto err_out;
+		if (!PyUnicode_Check(py_classval) && !PyLong_Check(py_classval)) {
+			srd_err("Options of type %s are not yet supported.", Py_TYPE(py_classval)->tp_name);
+			goto err_out;
+		}
+
+		if ((value = g_hash_table_lookup(options, key))) {
+			/* An override for this option was provided. */
+			if (PyUnicode_Check(py_classval)) {
+				if (!(py_optval = PyUnicode_FromString(value))) {
+					/* Some UTF-8 encoding error. */
+					PyErr_Clear();
+					goto err_out;
+				}
+			} else if (PyLong_Check(py_classval)) {
+				if (!(py_optval = PyLong_FromString(value, NULL, 0))) {
+					/* ValueError Exception */
+					PyErr_Clear();
+					srd_err("Option %s has invalid value %s: expected integer.",
+							key, value);
+					goto err_out;
+				}
+			}
+			g_hash_table_remove(options, key);
+		} else {
+			/* Use the class default for this option. */
+			if (PyUnicode_Check(py_classval)) {
+				/* Make a brand new copy of the string. */
+				py_ustr = PyUnicode_AS_UNICODE(py_classval);
+				size = PyUnicode_GET_SIZE(py_classval);
+				py_optval = PyUnicode_FromUnicode(py_ustr, size);
+			} else if (PyLong_Check(py_classval)) {
+				/* Make a brand new copy of the integer. */
+				val_ull = PyLong_AsUnsignedLongLong(py_classval);
+				if (val_ull == (unsigned long long)-1) {
+					/* OverFlowError exception */
+					PyErr_Clear();
+					srd_err("Invalid integer value for %s: expected integer.", key);
+					goto err_out;
+				}
+				if (!(py_optval = PyLong_FromUnsignedLongLong(val_ull)))
+					goto err_out;
+			}
+		}
 
-	PyRun_SimpleString("import sys");
-	ret = PyRun_SimpleString("sys.path.append(r'" DECODERS_DIR "');");
+		/* If we got here, py_optval holds a known good new reference
+		 * to the instance option to set.
+		 */
+		if (PyDict_SetItemString(py_di_options, key, py_optval) == -1)
+			goto err_out;
+	}
+
+	ret = SRD_OK;
+
+err_out:
+	Py_XDECREF(py_optlist);
+	Py_XDECREF(py_di_options);
+	Py_XDECREF(py_dec_optkeys);
+	Py_XDECREF(py_dec_options);
+	if (key)
+		g_free(key);
+	if (PyErr_Occurred())
+		catch_exception("Stray exception in srd_instance_set_options().");
 
 	return ret;
 }
 
+/* Helper GComparefunc for g_slist_find_custom() in srd_instance_set_probes() */
+static gint compare_probe_id(struct srd_probe *a, char *probe_id)
+{
+
+	return strcmp(a->id, probe_id);
+}
+
+/**
+ * Set probes in a decoder instance.
+ *
+ * @param di Decoder instance.
+ * @param probes A GHashTable of probes to set. Key is probe name, value is
+ * the probe number. Samples passed to this instance will be arranged in this
+ * order.
+ *
+ * @return SRD_OK upon success, a (negative) error code otherwise.
+ */
+int srd_instance_set_probes(struct srd_decoder_instance *di,
+		GHashTable *new_probes)
+{
+	GList *l;
+	GSList *sl;
+	struct srd_probe *p;
+	int *new_probemap, new_probenum;
+	char *probe_id, *probenum_str;
+
+	if (g_hash_table_size(new_probes) == 0)
+		/* No probes provided. */
+		return SRD_OK;
+
+	if(di->dec_num_probes == 0) {
+		/* Decoder has no probes. */
+		srd_err("Protocol decoder %s has no probes to define.",
+				di->decoder->name);
+		return SRD_ERR_ARG;
+	}
+
+	new_probemap = NULL;
+
+	if (!(new_probemap = g_try_malloc(sizeof(int) * di->dec_num_probes))) {
+		srd_err("Failed to malloc new probe map.");
+		return SRD_ERR_MALLOC;
+	}
+
+	for (l = g_hash_table_get_keys(new_probes); l; l = l->next) {
+		probe_id = l->data;
+		probenum_str = g_hash_table_lookup(new_probes, probe_id);
+		if (!probenum_str) {
+			/* Probe name was specified without a value. */
+			srd_err("No probe number was specified for %s.", probe_id);
+			g_free(new_probemap);
+			return SRD_ERR_ARG;
+		}
+		new_probenum = strtol(probenum_str, NULL, 10);
+		if (!(sl = g_slist_find_custom(di->decoder->probes, probe_id,
+				(GCompareFunc)compare_probe_id))) {
+			/* Fall back on optional probes. */
+			if (!(sl = g_slist_find_custom(di->decoder->extra_probes,
+					probe_id, (GCompareFunc)compare_probe_id))) {
+				srd_err("Protocol decoder %s has no probe '%s'.",
+						di->decoder->name, probe_id);
+				g_free(new_probemap);
+				return SRD_ERR_ARG;
+			}
+		}
+		p = sl->data;
+		new_probemap[p->order] = new_probenum;
+	}
+	g_free(di->dec_probemap);
+	di->dec_probemap = new_probemap;
+
+	return SRD_OK;
+}
 
-struct srd_decoder_instance *srd_instance_new(const char *id)
+/**
+ * Create a new protocol decoder instance.
+ *
+ * @param id Decoder 'id' field.
+ * @param options GHashtable of options which override the defaults set in
+ * 	    the decoder class.
+ * @return Pointer to a newly allocated struct srd_decoder_instance, or
+ * 		NULL in case of failure.
+ */
+struct srd_decoder_instance *srd_instance_new(const char *decoder_id,
+		GHashTable *options)
 {
 	struct srd_decoder *dec;
 	struct srd_decoder_instance *di;
-	PyObject *py_args;
+	int i;
+	char *instance_id;
 
-	fprintf(stdout, "%s: %s\n", __func__, id);
+	srd_dbg("Creating new %s instance.", decoder_id);
 
-	if (!(dec = srd_get_decoder_by_id(id)))
+	if (!(dec = srd_get_decoder_by_id(decoder_id))) {
+		srd_err("Protocol decoder %s not found.", decoder_id);
 		return NULL;
+	}
 
-	/* TODO: Error handling. Use g_try_malloc(). */
-	di = g_malloc(sizeof(*di));
+	if (!(di = g_try_malloc0(sizeof(*di)))) {
+		srd_err("Failed to malloc instance.");
+		return NULL;
+	}
+
+	instance_id = g_hash_table_lookup(options, "id");
 	di->decoder = dec;
-	di->pd_output = NULL;
-	di->unitsize = 0;
+	di->instance_id = g_strdup(instance_id ? instance_id : decoder_id);
+	g_hash_table_remove(options, "id");
+
+	/* Prepare a default probe map, where samples come in the
+	 * order in which the decoder class defined them.
+	 */
+	di->dec_num_probes = g_slist_length(di->decoder->probes) +
+			g_slist_length(di->decoder->extra_probes);
+	if (di->dec_num_probes) {
+		if (!(di->dec_probemap = g_try_malloc(sizeof(int) * di->dec_num_probes))) {
+			srd_err("Failed to malloc probe map.");
+			g_free(di);
+			return NULL;
+		}
+		for (i = 0; i < di->dec_num_probes; i++)
+			di->dec_probemap[i] = i;
+	}
 
-	/* Create an empty Python tuple. */
-	if (!(py_args = PyTuple_New(0))) { /* NEWREF */
+	/* Create a new instance of this decoder class. */
+	if (!(di->py_instance = PyObject_CallObject(dec->py_dec, NULL))) {
 		if (PyErr_Occurred())
-			PyErr_Print(); /* Returns void. */
-
-		return NULL; /* TODO: More specific error? */
+			catch_exception("failed to create %s instance: ", decoder_id);
+		g_free(di->dec_probemap);
+		g_free(di);
+		return NULL;
 	}
 
-	/* Create an instance of the 'Decoder' class. */
-	di->py_instance = PyObject_Call(dec->py_decobj, py_args, NULL);
-	if (!di->py_instance) {
-		if (PyErr_Occurred())
-			PyErr_Print(); /* Returns void. */
-		Py_XDECREF(py_args);
-		return NULL; /* TODO: More specific error? */
+	if (srd_instance_set_options(di, options) != SRD_OK) {
+		g_free(di->dec_probemap);
+		g_free(di);
+		return NULL;
 	}
-	di_list = g_slist_append(di_list, di);
 
-	Py_XDECREF(py_args);
+	/* Instance takes input from a frontend by default. */
+	di_list = g_slist_append(di_list, di);
 
 	return di;
 }
 
-
-int srd_instance_set_probe(struct srd_decoder_instance *di,
-			   const char *probename, int num)
+int srd_instance_stack(struct srd_decoder_instance *di_from,
+		struct srd_decoder_instance *di_to)
 {
-	PyObject *probedict, *probenum;
 
-	probedict = PyObject_GetAttrString(di->py_instance, "probes"); /* NEWREF */
-	if (!probedict) {
-		if (PyErr_Occurred())
-			PyErr_Print(); /* Returns void. */
-
-		return SRD_ERR_PYTHON; /* TODO: More specific error? */
+	if (!di_from || !di_to) {
+		srd_err("Invalid from/to instance pair.");
+		return SRD_ERR_ARG;
 	}
 
-	probenum = PyLong_FromLong(num);
-	PyMapping_SetItemString(probedict, (char *)probename, probenum);
+	if (g_slist_find(di_list, di_to)) {
+		/* Remove from the unstacked list. */
+		di_list = g_slist_remove(di_list, di_to);
+	}
 
-	Py_XDECREF(probenum);
-	Py_XDECREF(probedict);
+	/* Stack on top of source di. */
+	di_from->next_di = g_slist_append(di_from->next_di, di_to);
 
 	return SRD_OK;
 }
 
+/**
+ * Finds a decoder instance by its instance id, but only in the bottom
+ * level of instances -- instances already stacked on top of another one
+ * will not be found.
+ *
+ * @param instance_id The instance id to be found.
+ *
+ * @return Pointer to struct srd_decoder_instance, or NULL if not found.
+ */
+struct srd_decoder_instance *srd_instance_find_by_id(char *instance_id)
+{
+	GSList *l;
+	struct srd_decoder_instance *tmp, *di;
 
-int srd_session_start(int num_probes, int unitsize, uint64_t samplerate)
+	di = NULL;
+	for (l = di_list; l; l = l->next) {
+		tmp = l->data;
+		if (!strcmp(tmp->instance_id, instance_id)) {
+			di = tmp;
+			break;
+		}
+	}
+
+	return di;
+}
+
+/**
+ * Finds a decoder instance by its python object, i.e. that instance's
+ * instantiation of the sigrokdecode.Decoder class. This will recurse
+ * to find the instance anywhere in the stack tree.
+ *
+ * @param stack Pointer to a GSList of struct srd_decoder_instance,
+ * 		indicating the stack to search. To start searching at the bottom
+ * 		level of decoder instances, pass NULL.
+ * @param obj The python class instantiation.
+ *
+ * @return Pointer to struct srd_decoder_instance, or NULL if not found.
+ */
+struct srd_decoder_instance *srd_instance_find_by_obj(GSList *stack,
+		PyObject *obj)
 {
-	PyObject *py_res;
-	GSList *d;
-	struct srd_decoder_instance *di;
+	GSList *l;
+	struct srd_decoder_instance *tmp, *di;
+
+	di = NULL;
+	for (l = stack ? stack : di_list; di == NULL && l != NULL; l = l->next) {
+		tmp = l->data;
+		if (tmp->py_instance == obj)
+			di = tmp;
+		else if (tmp->next_di)
+			di = srd_instance_find_by_obj(tmp->next_di, obj);
+	}
 
-	fprintf(stdout, "%s\n", __func__);
+	return di;
+}
 
-	for (d = di_list; d; d = d->next) {
-		di = d->data;
-		di->num_probes = num_probes;
-		di->unitsize = unitsize;
-		di->samplerate = samplerate;
-		if (!(py_res = PyObject_CallMethod(di->py_instance, "start",
-				    "{s:l}",
-					"samplerate", (long)samplerate))) {
-			if (PyErr_Occurred())
-				PyErr_Print(); /* Returns void. */
-
-			return SRD_ERR_PYTHON; /* TODO: More specific error? */
-		}
-		Py_XDECREF(py_res);
+int srd_instance_start(struct srd_decoder_instance *di, PyObject *args)
+{
+	PyObject *py_name, *py_res;
+	GSList *l;
+	struct srd_decoder_instance *next_di;
+
+	srd_dbg("Calling start() method on protocol decoder instance %s.",
+		di->instance_id);
+
+	if (!(py_name = PyUnicode_FromString("start"))) {
+		srd_err("Unable to build python object for 'start'.");
+		catch_exception("Protocol decoder instance %s: ", di->instance_id);
+		return SRD_ERR_PYTHON;
+	}
+
+	if (!(py_res = PyObject_CallMethodObjArgs(di->py_instance,
+			py_name, args, NULL))) {
+		catch_exception("Protocol decoder instance %s: ", di->instance_id);
+		return SRD_ERR_PYTHON;
+	}
+
+	Py_DecRef(py_res);
+	Py_DecRef(py_name);
+
+	/* Start all the PDs stacked on top of this one. Pass along the
+	 * metadata all the way from the bottom PD, even though it's only
+	 * applicable to logic data for now.
+	 */
+	for (l = di->next_di; l; l = l->next) {
+		next_di = l->data;
+		srd_instance_start(next_di, args);
 	}
 
 	return SRD_OK;
 }
 
-
 /**
  * Run the specified decoder function.
  *
- * @param dec TODO
- * @param inbuf TODO
- * @param inbuflen TODO
+ * @param start_samplenum The starting sample number for the buffer's sample
+ * 			  set, relative to the start of capture.
+ * @param di The decoder instance to call. Must not be NULL.
+ * @param inbuf The buffer to decode. Must not be NULL.
+ * @param inbuflen Length of the buffer. Must be > 0.
  *
  * @return SRD_OK upon success, a (negative) error code otherwise.
  */
-int srd_run_decoder(uint64_t timeoffset, uint64_t duration,
-		struct srd_decoder_instance *di, uint8_t *inbuf, uint64_t inbuflen)
+int srd_instance_decode(uint64_t start_samplenum,
+	struct srd_decoder_instance *di, uint8_t *inbuf, uint64_t inbuflen)
 {
-	PyObject *py_instance, *py_res;
+	PyObject *py_res;
 	srd_logic *logic;
+	uint64_t end_samplenum;
 
-	/* Return an error upon unusable input. */
-	if (di == NULL)
-		return SRD_ERR_ARG; /* TODO: More specific error? */
-	if (inbuf == NULL)
-		return SRD_ERR_ARG; /* TODO: More specific error? */
-	if (inbuflen == 0) /* No point in working on empty buffers. */
-		return SRD_ERR_ARG; /* TODO: More specific error? */
+	srd_dbg("Calling decode() on instance %s with %d bytes starting "
+		"at sample %d.", di->instance_id, inbuflen, start_samplenum);
 
-	/* TODO: Error handling. */
-	py_instance = di->py_instance;
-	Py_XINCREF(py_instance);
+	/* Return an error upon unusable input. */
+	if (!di) {
+		srd_dbg("empty decoder instance");
+		return SRD_ERR_ARG;
+	}
+	if (!inbuf) {
+		srd_dbg("NULL buffer pointer");
+		return SRD_ERR_ARG;
+	}
+	if (inbuflen == 0) {
+		srd_dbg("empty buffer");
+		return SRD_ERR_ARG;
+	}
 
+	/* Create new srd_logic object. Each iteration around the PD's loop
+	 * will fill one sample into this object.
+	 */
 	logic = PyObject_New(srd_logic, &srd_logic_type);
 	Py_INCREF(logic);
 	logic->di = di;
+	logic->start_samplenum = start_samplenum;
 	logic->itercnt = 0;
 	logic->inbuf = inbuf;
 	logic->inbuflen = inbuflen;
 	logic->sample = PyList_New(2);
 	Py_INCREF(logic->sample);
 
-	if (!(py_res = PyObject_CallMethod(py_instance, "decode",
-			"KKO", timeoffset, duration, logic))) {
-		if (PyErr_Occurred())
-			PyErr_Print(); /* Returns void. */
-
+	Py_IncRef(di->py_instance);
+	end_samplenum = start_samplenum + inbuflen / di->data_unitsize;
+	if (!(py_res = PyObject_CallMethod(di->py_instance, "decode",
+			"KKO", logic->start_samplenum, end_samplenum, logic))) {
+		catch_exception("Protocol decoder instance %s: ", di->instance_id);
 		return SRD_ERR_PYTHON; /* TODO: More specific error? */
 	}
-
-	Py_XDECREF(py_res);
+	Py_DecRef(py_res);
 
 	return SRD_OK;
 }
 
 
-/* Feed logic samples to decoder session. */
-int srd_session_feed(uint64_t timeoffset, uint64_t duration, uint8_t *inbuf,
-		uint64_t inbuflen)
+int srd_session_start(int num_probes, int unitsize, uint64_t samplerate)
 {
+	PyObject *args;
 	GSList *d;
+	struct srd_decoder_instance *di;
 	int ret;
 
-//	fprintf(stdout, "%s: %d bytes\n", __func__, inbuflen);
+	srd_dbg("Calling start() on all instances with %d probes, "
+		"unitsize %d samplerate %d.", num_probes, unitsize, samplerate);
 
-	for (d = di_list; d; d = d->next) {
-		if ((ret = srd_run_decoder(timeoffset, duration, d->data, inbuf,
-				inbuflen)) != SRD_OK)
-			return ret;
+	/* Currently only one item of metadata is passed along to decoders,
+	 * samplerate. This can be extended as needed.
+	 */
+	if (!(args = Py_BuildValue("{s:l}", "samplerate", (long)samplerate))) {
+		srd_err("Unable to build python object for metadata.");
+		return SRD_ERR_PYTHON;
 	}
 
-	return SRD_OK;
-}
-
-
-int pd_output_new(struct srd_decoder_instance *di, int output_type,
-		char *protocol_id)
-{
-	struct srd_pd_output *pdo;
-
-	if (!(pdo = g_try_malloc(sizeof(struct srd_pd_output))))
-		return -1;
-
-	/* pdo_id is just a simple index, nothing is deleted from this list anway */
-	pdo->pdo_id = g_slist_length(di->pd_output);
-	pdo->output_type = output_type;
-	pdo->decoder = di->decoder;
-	pdo->protocol_id = g_strdup(protocol_id);
-	di->pd_output = g_slist_append(di->pd_output, pdo);
+	/* Run the start() method on all decoders receiving frontend data. */
+	for (d = di_list; d; d = d->next) {
+		di = d->data;
+		di->data_num_probes = num_probes;
+		di->data_unitsize = unitsize;
+		di->data_samplerate = samplerate;
+		if ((ret = srd_instance_start(di, args) != SRD_OK))
+			break;
+	}
 
-	fprintf(stdout, "%s: output type %d, protocol_id %s, id %d\n",
-			__func__, output_type, protocol_id, pdo->pdo_id);
+	Py_DecRef(args);
 
-	return pdo->pdo_id;
+	return ret;
 }
 
-struct srd_decoder_instance *get_di_by_decobject(void *decobject)
+/* Feed logic samples to decoder session. */
+int srd_session_feed(uint64_t start_samplenum, uint8_t *inbuf, uint64_t inbuflen)
 {
-	GSList *l;
-	struct srd_decoder_instance *di;
+	GSList *d;
+	int ret;
 
-	for (l = di_list; l; l = l->next) {
-		di = l->data;
-		if (decobject == di->py_instance)
-			return di;
+	srd_dbg("Calling decode() on all instances with starting sample "
+		"number %"PRIu64", %"PRIu64" bytes at 0x%p", start_samplenum,
+		inbuflen, inbuf);
+
+	for (d = di_list; d; d = d->next) {
+		if ((ret = srd_instance_decode(start_samplenum, d->data, inbuf,
+				inbuflen)) != SRD_OK)
+			return ret;
 	}
 
-	return NULL;
+	return SRD_OK;
 }
 
+
 int srd_register_callback(int output_type, void *cb)
 {
 	struct srd_pd_callback *pd_cb;
 
+	srd_dbg("Registering new callback for output type %d.", output_type);
+
 	if (!(pd_cb = g_try_malloc(sizeof(struct srd_pd_callback))))
 		return SRD_ERR_MALLOC;
 
@@ -339,7 +663,6 @@ int srd_register_callback(int output_type, void *cb)
 	pd_cb->callback = cb;
 	callbacks = g_slist_append(callbacks, pd_cb);
 
-	printf("got cb for %d: %p\n", output_type, cb);
 	return SRD_OK;
 }
 
@@ -361,12 +684,25 @@ void *srd_find_callback(int output_type)
 	return cb;
 }
 
-//int srd_pipeline_new(int plid)
-//{
-//
-//
-//}
 
+/* This is the backend function to python sigrokdecode.add() call. */
+int pd_add(struct srd_decoder_instance *di, int output_type, char *proto_id)
+{
+	struct srd_pd_output *pdo;
+
+	srd_dbg("Instance %s creating new output type %d for %s.",
+		di->instance_id, output_type, proto_id);
+
+	if (!(pdo = g_try_malloc(sizeof(struct srd_pd_output))))
+		return -1;
 
+	/* pdo_id is just a simple index, nothing is deleted from this list anyway. */
+	pdo->pdo_id = g_slist_length(di->pd_output);
+	pdo->output_type = output_type;
+	pdo->di = di;
+	pdo->proto_id = g_strdup(proto_id);
+	di->pd_output = g_slist_append(di->pd_output, pdo);
 
+	return pdo->pdo_id;
+}