Cleanup of allocation strategy

storage/xpand/ha_xpand.cc

@@ -75,15 +75,7 @@ static MYSQL_SYSVAR_ENUM
 //current list of clx hosts
 static PSI_rwlock_key key_xpand_hosts;
 mysql_rwlock_t xpand_hosts_lock;
-xpand_host_list *xpand_hosts;
-
-//only call while holding lock
-static void clear_hosts()
-{
-  delete xpand_hosts;
-  xpand_hosts = NULL;
-  my_atomic_store32(&xpand_hosts_cur, 0);
-}
+xpand_host_list xpand_hosts;
 
 static int check_hosts(MYSQL_THD thd, struct st_mysql_sys_var *var,
                        void *save, struct st_mysql_value *value)
@@ -91,37 +83,38 @@ static int check_hosts(MYSQL_THD thd, struct st_mysql_sys_var *var,
   char b;
   int len = 0;
   const char *val = value->val_str(value, &b, &len);
-
   if (!val)
     return HA_ERR_OUT_OF_MEM;
 
+  xpand_host_list *list = static_cast<xpand_host_list*>(
+                          thd_calloc(thd, sizeof(xpand_host_list)));
+  if (!list)
+    return HA_ERR_OUT_OF_MEM;
+
   int error_code = 0;
-  xpand_host_list *host_list = xpand_host_list::create(val, thd, &error_code);
-  if (error_code)
+  if ((error_code = list->fill(val)))
     return error_code;
+  list->empty();
 
-  *static_cast<xpand_host_list**>(save) = host_list;
+  *static_cast<char**>(save) = thd_strdup(thd, val);
   return 0;
 }
 
 static void update_hosts(MYSQL_THD thd, struct st_mysql_sys_var *var,
                          void *var_ptr, const void *save)
 {
-  mysql_rwlock_wrlock(&xpand_hosts_lock);
+  char *from_save = *static_cast<char * const *>(save);
 
-  xpand_host_list *from_save = *static_cast<xpand_host_list * const *>(save);
-  char* raw = from_save->full_list;
+  mysql_rwlock_wrlock(&xpand_hosts_lock);
 
-  int error_code = 0;
-  xpand_host_list *new_hosts = xpand_host_list::create(raw, &error_code);
+  xpand_hosts.empty();
+  int error_code = xpand_hosts.fill(from_save);
   if (error_code) {
     my_printf_error(error_code, "Unhandled error setting xpand hostlist", MYF(0));
     return;
   }
 
-  clear_hosts();
-  xpand_hosts = new_hosts;
-  *static_cast<char**>(var_ptr) = new_hosts->full_list;
+  *static_cast<char**>(var_ptr) = my_strdup(from_save, MYF(MY_WME));
 
   mysql_rwlock_unlock(&xpand_hosts_lock);
 }
@@ -1481,8 +1474,7 @@ static int xpand_init(void *p)
 
   mysql_rwlock_init(key_xpand_hosts, &xpand_hosts_lock);
   mysql_rwlock_wrlock(&xpand_hosts_lock);
-  int error_code = 0;
-  xpand_hosts = xpand_host_list::create(xpand_hosts_str, &error_code);
+  int error_code = xpand_hosts.fill(xpand_hosts_str);
   mysql_rwlock_unlock(&xpand_hosts_lock);
   DBUG_RETURN(error_code);
 }
@@ -1491,7 +1483,7 @@ static int xpand_deinit(void *p)
 {
   DBUG_ENTER("xpand_deinit");
   mysql_rwlock_wrlock(&xpand_hosts_lock);
-  delete xpand_hosts;
+  xpand_hosts.empty();
   mysql_rwlock_destroy(&xpand_hosts_lock);
   DBUG_RETURN(0);
 }

storage/xpand/xpand_connection.cc

@@ -21,7 +21,6 @@ Copyright (c) 2019, MariaDB Corporation.
 extern int xpand_connect_timeout;
 extern int xpand_read_timeout;
 extern int xpand_write_timeout;
-extern char *xpand_host;
 extern char *xpand_username;
 extern char *xpand_password;
 extern uint xpand_port;
@@ -130,7 +129,7 @@ extern int xpand_hosts_cur;
 extern ulong xpand_balance_algorithm;
 
 extern mysql_rwlock_t xpand_hosts_lock;
-extern xpand_host_list *xpand_hosts;
+extern xpand_host_list xpand_hosts;
 
 int xpand_connection::connect()
 {
@@ -142,9 +141,9 @@ int xpand_connection::connect()
   mysql_rwlock_rdlock(&xpand_hosts_lock);
 
   //search for available host
-  int error_code = 0;
-  for (int i = 0; i < xpand_hosts->hosts_len; i++) {
-    char *host = xpand_hosts->hosts[(start + i) % xpand_hosts->hosts_len];
+  int error_code = ER_BAD_HOST_ERROR;
+  for (int i = 0; i < xpand_hosts.hosts_len; i++) {
+    char *host = xpand_hosts.hosts[(start + i) % xpand_hosts.hosts_len];
     error_code = connect_direct(host);
     if (!error_code)
       break;
@@ -1290,31 +1289,11 @@ int xpand_connection::add_command_operand_bitmap(MY_BITMAP *bitmap)
 ** Class xpand_host_list
 ****************************************************************************/
 
-xpand_host_list *xpand_host_list::create(const char *hosts, int *error_code)
+int xpand_host_list::fill(const char *hosts)
 {
-  return xpand_host_list::create(hosts, NULL, error_code);
-}
-
-xpand_host_list *xpand_host_list::create(const char *hosts, THD *thd, int *error_code)
-{
-  xpand_host_list *list = static_cast<xpand_host_list*>(
-                          thd ?
-                          thd_calloc(thd, sizeof(xpand_host_list)) :
-                          my_malloc(sizeof(xpand_host_list), MYF(MY_WME | MY_ZEROFILL)));
-  if (!list) {
-    *error_code = HA_ERR_OUT_OF_MEM;
-    return NULL;
-  }
-
-  list->full_list = thd ?
-                    thd_strdup(thd, hosts) :
-                    my_strdup(hosts, MYF(MY_WME));
-  list->strtok_buf = thd ?
-                     thd_strdup(thd, hosts) :
-                     my_strdup(hosts, MYF(MY_WME));
-  if (!list->full_list || !list->strtok_buf) {
-    *error_code = HA_ERR_OUT_OF_MEM;
-    return NULL;
+  strtok_buf = my_strdup(hosts, MYF(MY_WME));
+  if (!strtok_buf) {
+    return HA_ERR_OUT_OF_MEM;
   }
 
   const char *sep = ",; ";
@@ -1322,32 +1301,26 @@ xpand_host_list *xpand_host_list::create(const char *hosts, THD *thd, int *error
   int i = 0;
   char *cursor = NULL;
   char *token = NULL;
-  for (token = strtok_r(list->strtok_buf, sep, &cursor);
+  for (token = strtok_r(strtok_buf, sep, &cursor);
        token && i < max_host_count;
        token = strtok_r(NULL, sep, &cursor)) {
-    list->hosts[i] = token;
+    this->hosts[i] = token;
     i++;
   }
 
   //host count out of range
   if (i == 0 || token) {
-    my_free(list->full_list);
-    my_free(list->strtok_buf);
-    my_free(list);
-    *error_code = ER_BAD_HOST_ERROR;
-    return NULL;
+    my_free(strtok_buf);
+    return ER_BAD_HOST_ERROR;
   }
-  list->hosts_len = i;
+  hosts_len = i;
 
-  return list;
+  return 0;
 }
 
-void xpand_host_list::operator delete(void *p)
+void xpand_host_list::empty()
 {
-  xpand_host_list *list = static_cast<xpand_host_list*>(p);
-  if (list) {
-    my_free(list->full_list);
-    my_free(list->strtok_buf);
-  }
-  my_free(list);
+  my_free(strtok_buf);
+  strtok_buf = NULL;
+  hosts_len = 0;
 }

storage/xpand/xpand_connection.h

@@ -32,22 +32,6 @@ enum xpand_balance_algorithm_enum {
   XPAND_BALANCE_ROUND_ROBIN
 };
 
-static const int max_host_count = 128;
-class xpand_host_list {
-private:
-  char *strtok_buf;
-public:
-  char *full_list;
-  int hosts_len;
-  char *hosts[max_host_count];
-
-  static xpand_host_list *create(const char *hosts, int *error_code);
-  static xpand_host_list *create(const char *hosts, THD *thd, int *error_code);
-  xpand_host_list() = delete;
-  static void operator delete(void *p);
-};
-
-
 class xpand_connection_cursor;
 class xpand_connection
 {
@@ -147,4 +131,17 @@ class xpand_connection
   int send_command();
   int read_query_response();
 };
+
+static const int max_host_count = 128;
+class xpand_host_list {
+private:
+  char *strtok_buf;
+public:
+  int hosts_len;
+  char *hosts[max_host_count];
+
+  int fill(const char *hosts);
+  void empty();
+};
+
 #endif  // _xpand_connection_h