]> sigrok.org Git - libsigrokdecode.git/blobdiff - controller.c
edid: move PD docstring to __init__.py
[libsigrokdecode.git] / controller.c
index a0e8bfe8d13b240a16dee82c66b4d564d58c323d..20927cf9b80525a32b5b60f960dc60471cbd6734 100644 (file)
  * 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);
 
@@ -117,212 +118,547 @@ 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
 
-       PyRun_SimpleString("import sys");
-       ret = PyRun_SimpleString("sys.path.append(r'" DECODERS_DIR "');");
+       /* 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;
 }
 
 
-struct srd_decoder_instance *srd_instance_new(const char *id)
+/**
+ * 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;
+                       }
+               }
+
+               /* 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);
+       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;
+
+       srd_dbg("set probes called for instance %s with list of %d probes",
+                       di->instance_id, g_hash_table_size(new_probes));
+
+       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;
+               srd_dbg("setting probe mapping for %d = probe %d", p->order, new_probenum);
+       }
+       g_free(di->dec_probemap);
+       di->dec_probemap = new_probemap;
+
+       return SRD_OK;
+}
+
+/**
+ * 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;
+
+       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;
 }
 
-
-int srd_session_start(int num_probes, int unitsize, uint64_t samplerate)
+/**
+ * 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)
 {
-       PyObject *py_res;
-       GSList *d;
-       struct srd_decoder_instance *di;
+       GSList *l;
+       struct srd_decoder_instance *tmp, *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? */
+       di = NULL;
+       for (l = di_list; l; l = l->next) {
+               tmp = l->data;
+               if (!strcmp(tmp->instance_id, instance_id)) {
+                       di = tmp;
+                       break;
                }
-               Py_XDECREF(py_res);
        }
 
-       return SRD_OK;
+       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)
+{
+       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);
+       }
+
+       return di;
+}
+
+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;
 
-       for (d = di_list; d; d = d->next) {
-               if ((ret = srd_run_decoder(timeoffset, duration, d->data, inbuf,
-                               inbuflen)) != SRD_OK)
-                       return ret;
-       }
+       srd_dbg("Calling start() on all instances with %d probes, "
+               "unitsize %d samplerate %d.", num_probes, unitsize, samplerate);
 
-       return SRD_OK;
-}
-
-
-int pd_add(struct srd_decoder_instance *di, int output_type,
-               char *protocol_id)
-{
-       struct srd_pd_output *pdo;
+       /* 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;
+       }
 
-       if (!(pdo = g_try_malloc(sizeof(struct srd_pd_output))))
-               return -1;
+       /* 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;
+       }
 
-       /* 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->decoder = di->decoder;
-       pdo->protocol_id = g_strdup(protocol_id);
-       di->pd_output = g_slist_append(di->pd_output, pdo);
+       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;
 
@@ -351,12 +687,25 @@ 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;
+}