srd: Prepend (not append) PD dirs to sys.path.

[libsigrokdecode.git] / controller.c

diff --git a/controller.c b/controller.c
index d2056915b831c961c90cc1373ecf395c89e7f478..f3c1446f9ac40a952180fad8415369965fb33b57 100644 (file)
--- a/controller.c
+++ b/controller.c
@@ -118,10 +118,19 @@ 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)
 {
@@ -143,9 +152,8 @@ int set_modulepath(void)
        path = g_strdup(DECODERS_DIR);
 #endif
 
-       /* TODO: Prepend instead of appending. */
        /* TODO: Sanity check on 'path' (length, escape special chars, ...). */
-       s = g_strdup_printf("import sys; sys.path.append(r'%s')", path);
+       s = g_strdup_printf("import sys; sys.path.insert(0, r'%s')", path);
 
        ret = PyRun_SimpleString(s);
 
@@ -266,11 +274,8 @@ err_out:
        Py_XDECREF(py_dec_options);
        if (key)
                g_free(key);
-       if (PyErr_Occurred()) {
-               srd_dbg("srd: stray exception!");
-               PyErr_Print();
-               PyErr_Clear();
-       }
+       if (PyErr_Occurred())
+               catch_exception("srd: stray exception in srd_instance_set_options()");
 
        return ret;
 }
@@ -299,7 +304,7 @@ int srd_instance_set_probes(struct srd_decoder_instance *di,
        GSList *sl;
        struct srd_probe *p;
        int *new_probemap, new_probenum;
-       char *probe_id;
+       char *probe_id, *probenum_str;
 
        if (g_hash_table_size(new_probes) == 0)
                /* No probes provided. */
@@ -321,7 +326,14 @@ int srd_instance_set_probes(struct srd_decoder_instance *di,
 
        for (l = g_hash_table_get_keys(new_probes); l; l = l->next) {
                probe_id = l->data;
-               new_probenum = strtol(g_hash_table_lookup(new_probes, probe_id), NULL, 10);
+               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. */
@@ -394,7 +406,7 @@ struct srd_decoder_instance *srd_instance_new(const char *decoder_id,
        /* Create a new instance of this decoder class. */
        if (!(di->py_instance = PyObject_CallObject(dec->py_dec, NULL))) {
                if (PyErr_Occurred())
-                       PyErr_Print();
+                       catch_exception("failed to create %s instance: ", decoder_id);
                g_free(di->dec_probemap);
                g_free(di);
                return NULL;
@@ -463,15 +475,13 @@ int srd_instance_start(struct srd_decoder_instance *di, PyObject *args)
 
        if (!(py_name = PyUnicode_FromString("start"))) {
                srd_err("Unable to build python object for 'start'.");
-               if (PyErr_Occurred())
-                       PyErr_Print();
+               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))) {
-               if (PyErr_Occurred())
-                       PyErr_Print();
+               catch_exception("Protocol decoder instance %s: ", di->instance_id);
                return SRD_ERR_PYTHON;
        }
 
@@ -533,9 +543,7 @@ int srd_instance_decode(uint64_t start_samplenum,
        end_samplenum = start_samplenum + inbuflen / di->data_unitsize;
        if (!(py_res = PyObject_CallMethod(di->py_instance, "decode",
                        "KKO", logic->start_samplenum, end_samplenum, logic))) {
-               if (PyErr_Occurred())
-                       PyErr_Print(); /* Returns void. */
-
+               catch_exception("Protocol decoder instance %s: ", di->instance_id);
                return SRD_ERR_PYTHON; /* TODO: More specific error? */
        }
        Py_DecRef(py_res);