dialplan: Allow re-pointing the default partition

This is useful in situations where script writers do not intend to cache
the default 'dialplan' table, rather only the named partitions.

Example syntax:
    db_default_url = "mysql://opensips:opensipsrw@127.0.0.1/opensips"
    ...
    modparam("dialplan", "partition", "
	pstn:
	    table_name = dialplan_pstn")
    modparam("dialplan", "partition", "default: pstn")

(cherry picked from commit efee343)
(cherry picked from commit 4abd261)

modules/dialplan/dialplan.c

@@ -259,6 +259,14 @@ static int dp_create_head(const str *in)
 		if (!params)
 			goto bad_input;
 
+		/* support for the "default: my_part" syntax */
+		if (!props->next && !params->next && !ZSTR(params->s)) {
+			dp_df_part = params->s;
+			LM_DBG("changing the default partition to '%.*s'\n",
+			       dp_df_part.len, dp_df_part.s);
+			return 0;
+		}
+
 		if (str_match(&params->s, _str(PARAM_URL))) {
 			have_db_url = 1;
 			dp_head_insert(DP_TYPE_URL, &params->next->s, &partition);
@@ -349,7 +357,7 @@ static int mod_init(void)
 	timerec_column.len      = strlen(timerec_column.s);
 	disabled_column.len 	= strlen(disabled_column.s);
 
-	if (!dp_df_head) {
+	if (!dp_df_head && str_match(&dp_df_part, _str(DEFAULT_PARTITION))) {
 		if (default_dp_db_url.s)
 			dp_head_insert(DP_TYPE_URL, &default_dp_db_url, &dp_df_part);
 
@@ -482,13 +490,12 @@ static int dp_update(struct sip_msg * msg, pv_spec_t * src, pv_spec_t * dest,
 
 static int fix_partition(void** param)
 {
-	str def_str = str_init(DEFAULT_PARTITION);
 	str *s=(str*)*param;
 
 	/* handle the special case when the fix is triggered for 
 	   missing parameter */
 	if (s==NULL)
-		s = &def_str;
+		s = &dp_df_part;
 
 	*param = (void*)dp_get_connection( s );
 	if (*param==NULL) {
@@ -842,10 +849,9 @@ static mi_response_t *mi_translate(const mi_params_t *params,
 static mi_response_t *mi_translate2(const mi_params_t *params,
 								struct mi_handler *async_hdl)
 {
-	str def_str = str_init(DEFAULT_PARTITION);
 	dp_connection_list_t *part;
 
-	part = dp_get_connection(&def_str);
+	part = dp_get_connection(&dp_df_part);
 	if (part==NULL){
 		LM_ERR("translating without partition, but no default defined\n");
 		return init_mi_error(404, MI_SSTR("'default' partition not found"));

modules/dialplan/doc/dialplan_admin.xml

@@ -346,15 +346,16 @@ modparam("dialplan", "partition", "
 		</example>
 
 		<example>
-		<title> The 'default' partition inherits its URL from <varname>'db_default_url'</varname></title>
+		<title> Define the 'pstn' partition and make it the 'default' partition, so we avoid loading the 'dialplan' table</title>
 		<programlisting format="linespecific">
 ...
 db_default_url = "mysql://opensips:opensipsrw@localhost/opensips"
 
 loadmodule "dialplan.so"
 modparam("dialplan", "partition", "
-	default:
-		table_name = dialplan")
+	pstn:
+		table_name = dialplan_pstn")
+modparam("dialplan", "partition", "default: pstn")
 ...
 		</programlisting>
 		</example>

modules/dialplan/dp_db.c

@@ -169,6 +169,7 @@ void dp_disconnect_db(dp_connection_list_p dp_conn)
 int init_data(void)
 {
 	dp_head_p start, tmp;
+	int found_df_part = 0;
 
 	start = dp_hlist;
 	if (!start) {
@@ -179,6 +180,10 @@ int init_data(void)
 	while (start) {
 		LM_DBG("Adding partition with name [%.*s]\n",
 				start->partition.len, start->partition.s);
+
+		if (str_match(&start->partition, &dp_df_part))
+			found_df_part = 1;
+
 		if (!dp_add_connection(start)) {
 			LM_ERR("failed to initialize partition '%.*s'\n",
 					start->partition.len, start->partition.s);
@@ -190,6 +195,12 @@ int init_data(void)
 		pkg_free(tmp);
 	}
 
+	if (!found_df_part) {
+		LM_ERR("partition '%.*s' is not defined\n",
+		       dp_df_part.len, dp_df_part.s);
+		return -1;
+	}
+
 	dp_hlist = NULL;
 	return 0;
 }