Decoder: check for duplicate register() calls in common backend code

Future implementations might call decoders' start() routine several
times, which makes them call register() again. It's desirable that the
common backend code copes with this condition, such that (the multitude
of) decoder implementations need not work around a specific constraint.

diff --git a/type_decoder.c b/type_decoder.c
index 7c711323a508436c9027ef526f9f3c446c1451ff..06842f9e9069230a44b03fef24e8cc5838a341c3 100644 (file)
--- a/type_decoder.c
+++ b/type_decoder.c
@@ -361,6 +361,9 @@ static PyObject *Decoder_register(PyObject *self, PyObject *args,
        char *proto_id, *meta_name, *meta_descr;
        char *keywords[] = {"output_type", "proto_id", "meta", NULL};
        PyGILState_STATE gstate;
+       gboolean is_meta;
+       GSList *l;
+       struct srd_pd_output *cmp;
 
        gstate = PyGILState_Ensure();
 
@@ -383,7 +386,8 @@ static PyObject *Decoder_register(PyObject *self, PyObject *args,
        }
 
        /* Check if the meta value's type is supported. */
-       if (output_type == SRD_OUTPUT_META) {
+       is_meta = output_type == SRD_OUTPUT_META;
+       if (is_meta) {
                if (meta_type_py == &PyLong_Type)
                        meta_type_gv = G_VARIANT_TYPE_INT64;
                else if (meta_type_py == &PyFloat_Type)
@@ -394,6 +398,30 @@ static PyObject *Decoder_register(PyObject *self, PyObject *args,
                }
        }
 
+       srd_dbg("Instance %s checking registration type %d for %s.",
+               di->inst_id, output_type, proto_id);
+       pdo = NULL;
+       for (l = di->pd_output; l; l = l->next) {
+               cmp = l->data;
+               if (cmp->output_type != output_type)
+                       continue;
+               if (strcmp(cmp->proto_id, proto_id) != 0)
+                       continue;
+               if (is_meta && cmp->meta_type != meta_type_gv)
+                       continue;
+               if (is_meta && strcmp(cmp->meta_name, meta_name) != 0)
+                       continue;
+               if (is_meta && strcmp(cmp->meta_descr, meta_descr) != 0)
+                       continue;
+               pdo = cmp;
+               break;
+       }
+       if (pdo) {
+               py_new_output_id = Py_BuildValue("i", pdo->pdo_id);
+               PyGILState_Release(gstate);
+               return py_new_output_id;
+       }
+
        srd_dbg("Instance %s creating new output type %d for %s.",
                di->inst_id, output_type, proto_id);