Server list handling functions consistency

The functions handling servers lists now act with a bit more
consistency, always returning the array size instead of NULL-
terminating arrays.

server/core/config.c

@@ -1057,22 +1057,45 @@ SERVER* config_get_server(const MXS_CONFIG_PARAMETER *params, const char *key)
     return server_find_by_unique_name(value);
 }
 
-SERVER** config_get_serverlist(const MXS_CONFIG_PARAMETER *params, const char *key)
+int config_get_server_list(const MXS_CONFIG_PARAMETER *params, const char *key,
+                           SERVER*** output)
 {
     const char *value = config_get_value_string(params, key);
     char **server_names = NULL;
-    SERVER **servers = NULL;
-    int n_names = config_parse_server_list(value, &server_names);
+    int found = 0;
+    const int n_names = config_parse_server_list(value, &server_names);
     if (n_names > 0)
     {
-        servers = server_find_by_unique_names(server_names, n_names);
+        SERVER** servers;
+        found = server_find_by_unique_names(server_names, n_names, &servers);
         for (int i = 0; i < n_names; i++)
         {
             MXS_FREE(server_names[i]);
         }
         MXS_FREE(server_names);
+
+        if (found)
+        {
+            /* Fill in the result array */
+            SERVER** result = MXS_CALLOC(found, sizeof(SERVER*));
+            if (result)
+            {
+                int res_ind = 0;
+                for (int i = 0; i < n_names; i++)
+                {
+                    if (servers[i])
+                    {
+                        result[res_ind] = servers[i];
+                        res_ind++;
+                    }
+                }
+                *output = result;
+                ss_dassert(found == res_ind);
+            }
+            MXS_FREE(servers);
+        }
     }
-    return servers;
+    return found;
 }
 
 char* config_copy_string(const MXS_CONFIG_PARAMETER *params, const char *key)
@@ -3470,7 +3493,7 @@ bool config_param_is_valid(const MXS_MODULE_PARAM *params, const char *key,
     return valid;
 }
 
-static int config_parse_server_list(const char *servers, char ***output_array)
+int config_parse_server_list(const char *servers, char ***output_array)
 {
     ss_dassert(servers);
 
@@ -3486,7 +3509,7 @@ static int config_parse_server_list(const char *servers, char ***output_array)
     char **results = MXS_CALLOC(out_arr_size, sizeof(char*));
     if (!results)
     {
-        return -1;
+        return 0;
     }
 
     /* Parse the server names from the list. They are separated by ',' and will
@@ -3531,8 +3554,10 @@ static int config_parse_server_list(const char *servers, char ***output_array)
     if (output_ind == 0)
     {
         MXS_FREE(results);
-        results = NULL;
     }
-    *output_array = results;
+    else
+    {
+        *output_array = results;
+    }
     return output_ind;
 }

server/core/maxscale/config.h

@@ -111,15 +111,4 @@ SSL_LISTENER *make_ssl_structure(CONFIG_CONTEXT *obj, bool require_cert, int *er
  */
 bool config_have_required_ssl_params(CONFIG_CONTEXT *obj);
 
-/**
- * Parses a list of server names and writes the results in an array of strings
- * with one server in each. The output array and its elements should be deallocated
- * by the caller. The server names are not checked to be valid servers.
- *
- * @param servers A list of server names.
- * @param output_array Save location for the array of server names. Set to null if none found.
- * @return How many servers were found and set into the array.
- */
-static int config_parse_server_list(const char *servers, char ***output_array);
-
 MXS_END_DECLS

server/core/server.c

@@ -296,39 +296,45 @@ SERVER * server_find_by_unique_name(const char *name)
     return server;
 }
 
-
-
 /**
  * Find several servers with the names specified in an array with a given size.
- * The returned array (but not the elements) should be freed by the caller, and
- * is null-terminated.
+ * The returned array (but not the elements) should be freed by the caller.
+ * If no valid server names were found or in case of error, nothing is written
+ * to the output parameter.
  *
  * @param servers An array of server names
- * @param size number of elements in the server names array
- * @return A null-terminated array of SERVERs. May contain less elements than
- * requested if some server names are not found.
+ * @param size Number of elements in the input server names array, equal to output
+ * size if any servers are found.
+ * @param output Where to save the output. Contains null elements for invalid server
+ * names. If all were invalid, the output is left untouched.
+ * @return Number of valid server names found
  */
-SERVER** server_find_by_unique_names(char **server_names, int size)
+int server_find_by_unique_names(char **server_names, int size, SERVER*** output)
 {
-    ss_dassert(server_names);
+    ss_dassert(server_names && (size > 0));
 
-    SERVER **results = MXS_CALLOC(size + 1, sizeof(SERVER*)); // +1 for null
+    SERVER **results = MXS_CALLOC(size, sizeof(SERVER*));
     if (!results)
     {
-        return NULL;
+        return 0;
     }
 
-    int res_ind = 0;
-    for (int i = 0; server_names[i] != NULL; i++)
+    int found = 0;
+    for (int i = 0; i < size; i++)
     {
-        SERVER *serv = server_find_by_unique_name(server_names[i]);
-        if (serv)
-        {
-            results[res_ind] = serv;
-            res_ind++;
-        }
+        results[i] = server_find_by_unique_name(server_names[i]);
+        found += (results[i]) ? 1 : 0;
     }
-    return results;
+
+    if (found)
+    {
+        *output = results;
+    }
+    else
+    {
+        MXS_FREE(results);
+    }
+    return found;
 }
 
 /**