Next big patch for loadable storage engines!

Handlerton array is now created instead of using sys_table_types_st. All storage engines can now have inits and giant ifdef's are now gone for startup. No compeltely clean yet, handlertons will next be merged with sys_table_types. Federated and archive now have real cleanup if their inits fail. 

sql/examples/ha_archive.cc

@@ -116,7 +116,7 @@
 */
 
 /* If the archive storage engine has been inited */
-static bool archive_inited= 0;
+static bool archive_inited= FALSE;
 /* Variables for archive share methods */
 pthread_mutex_t archive_mutex;
 static HASH archive_open_tables;
@@ -138,6 +138,10 @@ static HASH archive_open_tables;
 /* dummy handlerton - only to have something to return from archive_db_init */
 handlerton archive_hton = {
   "archive",
+  SHOW_OPTION_YES,
+  "Archive storage engine", 
+  DB_TYPE_ARCHIVE_DB,
+  archive_db_init,
   0,       /* slot */
   0,       /* savepoint size. */
   NULL,    /* close_connection */
@@ -176,18 +180,29 @@ static byte* archive_get_key(ARCHIVE_SHARE *share,uint *length,
     void
 
   RETURN
-    &archive_hton OK
-    0             Error
+    FALSE       OK
+    TRUE        Error
 */
 
-handlerton *archive_db_init()
+bool archive_db_init()
 {
-  archive_inited= 1;
-  VOID(pthread_mutex_init(&archive_mutex, MY_MUTEX_INIT_FAST));
+  DBUG_ENTER("archive_db_init");
+  if (pthread_mutex_init(&archive_mutex, MY_MUTEX_INIT_FAST))
+    goto error;
   if (hash_init(&archive_open_tables, system_charset_info, 32, 0, 0,
                 (hash_get_key) archive_get_key, 0, 0))
-    return 0;
-  return &archive_hton;
+  {
+    VOID(pthread_mutex_destroy(&archive_mutex));
+  }
+  else
+  {
+    archive_inited= TRUE;
+    DBUG_RETURN(FALSE);
+  }
+error:
+  have_archive_db= SHOW_OPTION_DISABLED;	// If we couldn't use handler
+  archive_hton.state= SHOW_OPTION_DISABLED;
+  DBUG_RETURN(TRUE);
 }
 
 /*

sql/examples/ha_archive.h

@@ -105,6 +105,6 @@ public:
                              enum thr_lock_type lock_type);
 };
 
-handlerton *archive_db_init(void);
+bool archive_db_init(void);
 bool archive_db_end(void);
 

sql/examples/ha_example.cc

@@ -74,7 +74,11 @@
 
 
 handlerton example_hton= {
-  "CSV",
+  "EXAMPLE",
+  SHOW_OPTION_YES,
+  "Example storage engine", 
+  DB_TYPE_EXAMPLE_DB,
+  NULL,    /* We do need to write one! */
   0,       /* slot */
   0,       /* savepoint size. */
   NULL,    /* close_connection */

sql/examples/ha_tina.cc

@@ -56,6 +56,10 @@ static int tina_init= 0;
 
 handlerton tina_hton= {
   "CSV",
+  SHOW_OPTION_YES,
+  "CSV storage engine", 
+  DB_TYPE_CSV_DB,
+  NULL,    /* One needs to be written! */
   0,       /* slot */
   0,       /* savepoint size. */
   NULL,    /* close_connection */

sql/ha_berkeley.cc

@@ -109,6 +109,10 @@ static int berkeley_rollback(THD *thd, bool all);
 
 handlerton berkeley_hton = {
   "BerkeleyDB",
+  SHOW_OPTION_YES,
+  "Supports transactions and page-level locking", 
+  DB_TYPE_BERKELEY_DB,
+  berkeley_init,
   0, /* slot */
   0, /* savepoint size */
   berkeley_close_connection,
@@ -135,10 +139,13 @@ typedef struct st_berkeley_trx_data {
 
 /* General functions */
 
-handlerton *berkeley_init(void)
+bool berkeley_init(void)
 {
   DBUG_ENTER("berkeley_init");
 
+  if (have_berkeley_db != SHOW_OPTION_YES)
+    goto error;
+
   if (!berkeley_tmpdir)
     berkeley_tmpdir=mysql_tmpdir;
   if (!berkeley_home)
@@ -164,7 +171,7 @@ handlerton *berkeley_init(void)
   berkeley_log_file_size= max(berkeley_log_file_size, 10*1024*1024L);
 
   if (db_env_create(&db_env,0))
-    DBUG_RETURN(0);
+    goto error;
   db_env->set_errcall(db_env,berkeley_print_error);
   db_env->set_errpfx(db_env,"bdb");
   db_env->set_noticecall(db_env, berkeley_noticecall);
@@ -194,13 +201,17 @@ handlerton *berkeley_init(void)
   {
     db_env->close(db_env,0);
     db_env=0;
-    DBUG_RETURN(0);
+    goto error;
   }
 
   (void) hash_init(&bdb_open_tables,system_charset_info,32,0,0,
 		   (hash_get_key) bdb_get_key,0,0);
   pthread_mutex_init(&bdb_mutex,MY_MUTEX_INIT_FAST);
-  DBUG_RETURN(&berkeley_hton);
+  DBUG_RETURN(FALSE);
+error:
+  have_berkeley_db= SHOW_OPTION_DISABLED;	// If we couldn't use handler
+  berkeley_hton.state= SHOW_OPTION_DISABLED;
+  DBUG_RETURN(TRUE);
 }
 
 

sql/ha_berkeley.h

@@ -161,7 +161,7 @@ extern char *berkeley_home, *berkeley_tmpdir, *berkeley_logdir;
 extern long berkeley_lock_scan_time;
 extern TYPELIB berkeley_lock_typelib;
 
-handlerton *berkeley_init(void);
+bool berkeley_init(void);
 bool berkeley_end(void);
 bool berkeley_flush_logs(void);
 int berkeley_show_logs(Protocol *protocol);

sql/ha_blackhole.cc

@@ -28,6 +28,10 @@
 
 handlerton blackhole_hton= {
   "BLACKHOLE",
+  SHOW_OPTION_YES,
+  "/dev/null storage engine (anything you write to it disappears)",
+  DB_TYPE_BLACKHOLE_DB,
+  NULL,
   0,       /* slot */
   0,       /* savepoint size. */
   NULL,    /* close_connection */

sql/ha_federated.cc

@@ -363,6 +363,33 @@ pthread_mutex_t federated_mutex;                // This is the mutex we use to
 static int federated_init= FALSE;               // Variable for checking the
                                                 // init state of hash
 
+/* Federated storage engine handlerton */
+
+handlerton federated_hton= {
+  "FEDERATED",
+  SHOW_OPTION_YES,
+  "Federated MySQL storage engine", 
+  DB_TYPE_FEDERATED_DB,
+  federated_db_init,
+  0,       /* slot */
+  0,       /* savepoint size. */
+  NULL,    /* close_connection */
+  NULL,    /* savepoint */
+  NULL,    /* rollback to savepoint */
+  NULL,    /* release savepoint */
+  NULL,    /* commit */
+  NULL,    /* rollback */
+  NULL,    /* prepare */
+  NULL,    /* recover */
+  NULL,    /* commit_by_xid */
+  NULL,    /* rollback_by_xid */
+  NULL,    /* create_cursor_read_view */
+  NULL,    /* set_cursor_read_view */
+  NULL,    /* close_cursor_read_view */
+  HTON_NO_FLAGS
+};
+
+
 /* Function we use in the creation of our hash to get key.  */
 
 static byte *federated_get_key(FEDERATED_SHARE *share, uint *length,
@@ -386,10 +413,23 @@ static byte *federated_get_key(FEDERATED_SHARE *share, uint *length,
 
 bool federated_db_init()
 {
-  federated_init= 1;
-  VOID(pthread_mutex_init(&federated_mutex, MY_MUTEX_INIT_FAST));
-  return (hash_init(&federated_open_tables, system_charset_info, 32, 0, 0,
-                    (hash_get_key) federated_get_key, 0, 0));
+  DBUG_ENTER("federated_db_init");
+  if (pthread_mutex_init(&federated_mutex, MY_MUTEX_INIT_FAST))
+    goto error;
+  if (hash_init(&federated_open_tables, system_charset_info, 32, 0, 0,
+                    (hash_get_key) federated_get_key, 0, 0))
+  {
+    VOID(pthread_mutex_destroy(&federated_mutex));
+  }
+  else
+  {
+    federated_init= TRUE;
+    DBUG_RETURN(FALSE);
+  }
+error:
+  have_federated_db= SHOW_OPTION_DISABLED;	// If we couldn't use handler
+  federated_hton.state= SHOW_OPTION_DISABLED;
+  DBUG_RETURN(TRUE);
 }
 
 
@@ -694,29 +734,6 @@ error:
 }
 
 
-/* Federated storage engine handlerton */
-
-handlerton federated_hton= {
-  "FEDERATED",
-  0,       /* slot */
-  0,       /* savepoint size. */
-  NULL,    /* close_connection */
-  NULL,    /* savepoint */
-  NULL,    /* rollback to savepoint */
-  NULL,    /* release savepoint */
-  NULL,    /* commit */
-  NULL,    /* rollback */
-  NULL,    /* prepare */
-  NULL,    /* recover */
-  NULL,    /* commit_by_xid */
-  NULL,    /* rollback_by_xid */
-  NULL,    /* create_cursor_read_view */
-  NULL,    /* set_cursor_read_view */
-  NULL,    /* close_cursor_read_view */
-  HTON_NO_FLAGS
-};
-
-
 /*****************************************************************************
 ** FEDERATED tables
 *****************************************************************************/

sql/ha_heap.cc

@@ -25,6 +25,10 @@
 
 handlerton heap_hton= {
   "MEMORY",
+  SHOW_OPTION_YES,
+  "Hash based, stored in memory, useful for temporary tables", 
+  DB_TYPE_HEAP,
+  NULL,
   0,       /* slot */
   0,       /* savepoint size. */
   NULL,    /* close_connection */

sql/ha_innodb.cc

@@ -208,6 +208,10 @@ static int innobase_release_savepoint(THD* thd, void *savepoint);
 
 handlerton innobase_hton = {
   "InnoDB",
+  SHOW_OPTION_YES,
+  "Supports transactions, row-level locking, and foreign keys", 
+  DB_TYPE_INNODB,
+  innobase_init,
   0,				/* slot */
   sizeof(trx_named_savept_t),	/* savepoint size. TODO: use it */
   innobase_close_connection,
@@ -1188,7 +1192,7 @@ ha_innobase::init_table_handle_for_HANDLER(void)
 /*************************************************************************
 Opens an InnoDB database. */
 
-handlerton*
+bool
 innobase_init(void)
 /*===============*/
 			/* out: TRUE if error */
@@ -1200,6 +1204,9 @@ innobase_init(void)
 
   	DBUG_ENTER("innobase_init");
 
+         if (have_innodb != SHOW_OPTION_YES)
+           goto error;
+
 	ut_a(DATA_MYSQL_TRUE_VARCHAR == (ulint)MYSQL_TYPE_VARCHAR);
 
   	os_innodb_umask = (ulint)my_umask;
@@ -1267,7 +1274,7 @@ innobase_init(void)
 			"InnoDB: syntax error in innodb_data_file_path");
 	  	my_free(internal_innobase_data_file_path,
 						MYF(MY_ALLOW_ZERO_PTR));
-	  	DBUG_RETURN(0);
+                goto error;
 	}
 
 	/* -------------- Log files ---------------------------*/
@@ -1298,7 +1305,7 @@ innobase_init(void)
 
 	  	my_free(internal_innobase_data_file_path,
 						MYF(MY_ALLOW_ZERO_PTR));
-		DBUG_RETURN(0);
+                goto error;
 	}
 
 	/* --------------------------------------------------*/
@@ -1386,7 +1393,7 @@ innobase_init(void)
 	if (err != DB_SUCCESS) {
 	  	my_free(internal_innobase_data_file_path,
 						MYF(MY_ALLOW_ZERO_PTR));
-		DBUG_RETURN(0);
+                goto error;
 	}
 
 	(void) hash_init(&innobase_open_tables,system_charset_info, 32, 0, 0,
@@ -1413,7 +1420,11 @@ innobase_init(void)
 		glob_mi.pos = trx_sys_mysql_master_log_pos;
 	}
 */
-	DBUG_RETURN(&innobase_hton);
+	DBUG_RETURN(FALSE);
+error:
+        have_innodb= SHOW_OPTION_DISABLED;	// If we couldn't use handler
+        innobase_hton.state= SHOW_OPTION_DISABLED;
+        DBUG_RETURN(TRUE);
 }
 
 /***********************************************************************

sql/ha_innodb.h

@@ -241,7 +241,7 @@ extern ulong srv_commit_concurrency;
 
 extern TYPELIB innobase_lock_typelib;
 
-handlerton *innobase_init(void);
+bool innobase_init(void);
 bool innobase_end(void);
 bool innobase_flush_logs(void);
 uint innobase_get_free_space(void);

sql/ha_myisam.cc

@@ -54,6 +54,10 @@ TYPELIB myisam_stats_method_typelib= {
 
 handlerton myisam_hton= {
   "MyISAM",
+  SHOW_OPTION_YES,
+  "Default engine as of MySQL 3.23 with great performance", 
+  DB_TYPE_MYISAM,
+  NULL,
   0,       /* slot */
   0,       /* savepoint size. */
   NULL,    /* close_connection */

sql/ha_myisammrg.cc

@@ -36,6 +36,10 @@
 
 handlerton myisammrg_hton= {
   "MRG_MYISAM",
+  SHOW_OPTION_YES,
+  "Collection of identical MyISAM tables", 
+  DB_TYPE_MRG_MYISAM,
+  NULL,
   0,       /* slot */
   0,       /* savepoint size. */
   NULL,    /* close_connection */

sql/ha_ndbcluster.cc

@@ -51,6 +51,10 @@ static int ndbcluster_rollback(THD *thd, bool all);
 
 handlerton ndbcluster_hton = {
   "ndbcluster",
+  SHOW_OPTION_YES,
+  "Clustered, fault-tolerant, memory-based tables", 
+  DB_TYPE_NDBCLUSTER,
+  ndbcluster_init,
   0, /* slot */
   0, /* savepoint size */
   ndbcluster_close_connection,
@@ -4734,11 +4738,14 @@ static int connect_callback()
   return 0;
 }
 
-handlerton *
-ndbcluster_init()
+bool ndbcluster_init()
 {
   int res;
   DBUG_ENTER("ndbcluster_init");
+
+  if (have_ndbcluster != SHOW_OPTION_YES)
+    goto ndbcluster_init_error;
+
   // Set connectstring if specified
   if (opt_ndbcluster_connectstring != 0)
     DBUG_PRINT("connectstring", ("%s", opt_ndbcluster_connectstring));     
@@ -4819,16 +4826,18 @@ ndbcluster_init()
   }
   
   ndbcluster_inited= 1;
-  DBUG_RETURN(&ndbcluster_hton);
+  DBUG_RETURN(FALSE);
 
- ndbcluster_init_error:
+ndbcluster_init_error:
   if (g_ndb)
     delete g_ndb;
   g_ndb= NULL;
   if (g_ndb_cluster_connection)
     delete g_ndb_cluster_connection;
   g_ndb_cluster_connection= NULL;
-  DBUG_RETURN(NULL);
+  have_ndbcluster= SHOW_OPTION_DISABLED;	// If we couldn't use handler
+  ndbcluster_hton.state= SHOW_OPTION_DISABLED;
+  DBUG_RETURN(TRUE);
 }
 
 

sql/ha_ndbcluster.h

@@ -716,7 +716,7 @@ private:
 
 extern struct show_var_st ndb_status_variables[];
 
-handlerton *ndbcluster_init(void);
+bool ndbcluster_init(void);
 bool ndbcluster_end(void);
 
 int ndbcluster_discover(THD* thd, const char* dbname, const char* name,

sql/handler.cc

@@ -63,6 +63,7 @@ extern handlerton federated_hton;
 extern handlerton myisam_hton;
 extern handlerton myisammrg_hton;
 extern handlerton heap_hton;
+extern handlerton binlog_hton;
 
 
 	/* static functions defined in this file */
@@ -80,41 +81,38 @@ ulong total_ha_2pc;
 ulong savepoint_alloc_size;
 
 /*
-  This structure will go away in the future.
+  This array is used for processing compiled in engines.
 */
-struct show_table_type_st sys_table_types[]=
-{
-  {"MyISAM",	&have_yes,
-   "Default engine as of MySQL 3.23 with great performance", DB_TYPE_MYISAM,
-   NULL},
-  {"MEMORY",	&have_yes,
-   "Hash based, stored in memory, useful for temporary tables", DB_TYPE_HEAP,
-   NULL},
-  {"MRG_MYISAM",	&have_yes,
-   "Collection of identical MyISAM tables", DB_TYPE_MRG_MYISAM, NULL},
-  {"ISAM",	&have_isam,
-   "Obsolete storage engine, now replaced by MyISAM", DB_TYPE_ISAM, NULL},
-  {"MRG_ISAM",  &have_isam,
-   "Obsolete storage engine, now replaced by MERGE", DB_TYPE_MRG_ISAM, NULL},
-  {"InnoDB",	&have_innodb,
-   "Supports transactions, row-level locking, and foreign keys", DB_TYPE_INNODB,
-   NULL},
-  {"BERKELEYDB",	&have_berkeley_db,
-   "Supports transactions and page-level locking", DB_TYPE_BERKELEY_DB, NULL},
-  {"NDBCLUSTER", &have_ndbcluster,
-   "Clustered, fault-tolerant, memory-based tables", DB_TYPE_NDBCLUSTER, NULL},
-  {"EXAMPLE",&have_example_db,
-   "Example storage engine", DB_TYPE_EXAMPLE_DB, NULL},
-  {"ARCHIVE",&have_archive_db,
-   "Archive storage engine", DB_TYPE_ARCHIVE_DB, NULL},
-  {"CSV",&have_csv_db,
-   "CSV storage engine", DB_TYPE_CSV_DB, NULL},
-  {"FEDERATED",&have_federated_db,
-   "Federated MySQL storage engine", DB_TYPE_FEDERATED_DB, NULL},
-  {"BLACKHOLE",&have_blackhole_db,
-   "/dev/null storage engine (anything you write to it disappears)",
-   DB_TYPE_BLACKHOLE_DB, NULL},
-  {NullS, NULL, NullS, DB_TYPE_UNKNOWN, NULL}
+handlerton *sys_table_types[]=
+{
+  &myisam_hton,
+  &heap_hton,
+#ifdef HAVE_INNOBASE_DB
+  &innobase_hton,
+#endif
+#ifdef HAVE_BERKELEY_DB
+  &berkeley_hton,
+#endif
+#ifdef HAVE_BLACKHOLE_DB
+  &blackhole_hton,
+#endif
+#ifdef HAVE_EXAMPLE_DB
+  &example_hton,
+#endif
+#ifdef HAVE_ARCHIVE_DB
+  &archive_hton,
+#endif
+#ifdef HAVE_CSV_DB
+  &tina_hton,
+#endif
+#ifdef HAVE_NDBCLUSTER_DB
+  &ndbcluster_hton,
+#endif
+#ifdef HAVE_FEDERATED_DB
+  &federated_hton,
+#endif
+  &myisammrg_hton,
+  NULL
 };
 
 struct show_table_alias_st sys_table_aliases[]=
@@ -144,17 +142,17 @@ enum db_type ha_resolve_by_name(const char *name, uint namelen)
 {
   THD *thd= current_thd;
   show_table_alias_st *table_alias;
-  show_table_type_st *types;
+  handlerton **types;
   const char *ptr= name;
 
   if (thd && !my_strcasecmp(&my_charset_latin1, ptr, "DEFAULT"))
     return (enum db_type) thd->variables.table_type;
 
 retest:
-  for (types= sys_table_types; types->type; types++)
+  for (types= sys_table_types; *types; types++)
   {
-    if (!my_strcasecmp(&my_charset_latin1, ptr, types->type))
-      return (enum db_type) types->db_type;
+    if (!my_strcasecmp(&my_charset_latin1, ptr, (*types)->name))
+      return (enum db_type) (*types)->db_type;
   }
 
   /*
@@ -173,11 +171,11 @@ retest:
 }
 const char *ha_get_storage_engine(enum db_type db_type)
 {
-  show_table_type_st *types;
-  for (types= sys_table_types; types->type; types++)
+  handlerton **types;
+  for (types= sys_table_types; *types; types++)
   {
-    if (db_type == types->db_type)
-      return types->type;
+    if (db_type == (*types)->db_type)
+      return (*types)->name;
   }
 
   return "none";
@@ -186,18 +184,18 @@ const char *ha_get_storage_engine(enum db_type db_type)
 
 my_bool ha_storage_engine_is_enabled(enum db_type database_type)
 {
-  show_table_type_st *types;
-  for (types= sys_table_types; types->type; types++)
+  handlerton **types;
+  for (types= sys_table_types; *types; types++)
   {
-    if ((database_type == types->db_type) &&
-	(*types->value == SHOW_OPTION_YES))
+    if ((database_type == (*types)->db_type) &&
+	((*types)->state == SHOW_OPTION_YES))
       return TRUE;
   }
   return FALSE;
 }
 
 
-	/* Use other database handler if databasehandler is not incompiled */
+/* Use other database handler if databasehandler is not compiled in */
 
 enum db_type ha_checktype(THD *thd, enum db_type database_type,
                           bool no_substitute, bool report_error)
@@ -395,7 +393,7 @@ int ha_init()
 {
   int error= 0;
   handlerton **ht= handlertons;
-  show_table_type_st *types;
+  handlerton **types;
   show_table_alias_st *table_alias;
   total_ha= savepoint_alloc_size= 0;
 
@@ -405,132 +403,35 @@ int ha_init()
   /*
     This will go away soon.
   */
-  for (types= sys_table_types; types->type; types++)
-  {
-    switch (types->db_type) {
-    case DB_TYPE_HEAP:
-      types->ht= &heap_hton;
-      break;
-    case DB_TYPE_MYISAM:
-      types->ht= &myisam_hton;
-      break;
-    case DB_TYPE_MRG_MYISAM:
-      types->ht= &myisammrg_hton;
-      break;
-#ifdef HAVE_BERKELEY_DB
-    case DB_TYPE_BERKELEY_DB:
-      if (have_berkeley_db == SHOW_OPTION_YES)
-      {
-        if (!(*ht= berkeley_init()))
-        {
-          have_berkeley_db= SHOW_OPTION_DISABLED;	// If we couldn't use handler
-          error= 1;
-        }
-        else
-        {
-          types->ht= &berkeley_hton;
-          ha_was_inited_ok(ht++);
-        }
-      }
-      break;
-#endif
-#ifdef HAVE_INNOBASE_DB
-    case DB_TYPE_INNODB:
-      if (have_innodb == SHOW_OPTION_YES)
-      {
-        if (!(*ht= innobase_init()))
-        {
-          have_innodb= SHOW_OPTION_DISABLED;	// If we couldn't use handler
-          error= 1;
-        }
-        else
-        {
-          ha_was_inited_ok(ht++);
-          types->ht= &innobase_hton;
-        }
-      }
-      break;
-#endif
-#ifdef HAVE_NDBCLUSTER_DB
-    case DB_TYPE_NDBCLUSTER:
-      if (have_ndbcluster == SHOW_OPTION_YES)
-      {
-        if (!(*ht= ndbcluster_init()))
-        {
-          have_ndbcluster= SHOW_OPTION_DISABLED;
-          error= 1;
-        }
-        else
-        {
-          ha_was_inited_ok(ht++);
-          types->ht= &ndbcluster_hton;
-        }
-      }
-      break;
-#endif
-#ifdef HAVE_EXAMPLE_DB
-    case DB_TYPE_EXAMPLE_DB:
-      types->ht= &example_hton;
-      break;
-#endif
-#ifdef HAVE_ARCHIVE_DB
-    case DB_TYPE_ARCHIVE_DB:
-      if (have_archive_db == SHOW_OPTION_YES)
-      {
-        if (!(*ht= archive_db_init()))
-        {
-          have_archive_db= SHOW_OPTION_DISABLED;
-          error= 1;
-        }
-        else
-        {
-          ha_was_inited_ok(ht++);
-          types->ht= &archive_hton;
-        }
-      }
-      break;
-#endif
-#ifdef HAVE_CSV_DB
-    case DB_TYPE_CSV_DB:
-      types->ht= &tina_hton;
-      break;
-#endif
-#ifdef HAVE_FEDERATED_DB
-    case DB_TYPE_FEDERATED_DB:
-      if (have_federated_db == SHOW_OPTION_YES)
-      {
-        if (federated_db_init())
+  for (types= sys_table_types; *types; types++)
   {
-          have_federated_db= SHOW_OPTION_DISABLED;
-          error= 1;
-        }
-        else 
+    /*
+      FUTURE -
+      We need to collapse sys_table_types and handlertons variables into 
+      one variable.
+    */
+    *ht= *types;
+    ht++;
+    if ((*types)->init)
     {
-          types->ht= &federated_hton;
-        }
-      }
-      break;
-#endif
-#ifdef HAVE_BLACKHOLE_DB
-    case DB_TYPE_BLACKHOLE_DB:
-      types->ht= &blackhole_hton;
-      break;
-#endif
-    default:
-      types->ht= NULL;
+      if (!(*types)->init())
+        ha_was_inited_ok(types); 
     }
   }
 
   if (opt_bin_log)
   {
-    if (!(*ht= binlog_init()))                  // Always succeed
+    if (0) // Should fail until binlog is a bit more se like
     {
       mysql_bin_log.close(LOG_CLOSE_INDEX);     // Never used
       opt_bin_log= 0;                           // Never used
       error= 1;                                 // Never used
     }
     else
-      ha_was_inited_ok(ht++);
+    {
+      *types= &binlog_hton;
+      ha_was_inited_ok(types);
+    }
   }
   DBUG_ASSERT(total_ha < MAX_HA);
   /*
@@ -2525,7 +2426,7 @@ TYPELIB *ha_known_exts(void)
 {
   if (!known_extensions.type_names || mysys_usage_id != known_extensions_id)
   {
-    show_table_type_st *types;
+    handlerton **types;
     List<char> found_exts;
     List_iterator_fast<char> it(found_exts);
     const char **ext, *old_ext;
@@ -2533,11 +2434,11 @@ TYPELIB *ha_known_exts(void)
     known_extensions_id= mysys_usage_id;
     found_exts.push_back((char*) triggers_file_ext);
     found_exts.push_back((char*) trigname_file_ext);
-    for (types= sys_table_types; types->type; types++)
+    for (types= sys_table_types; *types; types++)
     {
-      if (*types->value == SHOW_OPTION_YES)
+      if ((*types)->state == SHOW_OPTION_YES)
       {
-	handler *file= get_new_handler(0,(enum db_type) types->db_type);
+	handler *file= get_new_handler(0,(enum db_type) (*types)->db_type);
 	for (ext= file->bas_ext(); *ext; ext++)
 	{
 	  while ((old_ext= it++))

sql/handler.h

@@ -297,6 +297,27 @@ typedef struct
     storage engine name as it should be printed to a user
   */
   const char *name;
+
+  /*
+    Historical marker for if the engine is available of not 
+  */
+  SHOW_COMP_OPTION state;
+
+  /*
+    A comment used by SHOW to describe an engine.
+  */
+  const char *comment;
+
+  /*
+    Historical number used for frm file to determine the correct storage engine.
+    This is going away and new engines will just use "name" for this.
+  */
+  enum db_type db_type;
+  /* 
+    Method that initizlizes a storage engine
+  */
+  bool (*init)();
+
   /*
     each storage engine has it's own memory area (actually a pointer)
     in the thd, for storing per-connection information.
@@ -356,14 +377,6 @@ typedef struct
    uint32 flags;                                /* global handler flags */
 } handlerton;
 
-struct show_table_type_st {
-  const char *type;
-  SHOW_COMP_OPTION *value;
-  const char *comment;
-  enum db_type db_type;
-  handlerton *ht;
-};
-
 struct show_table_alias_st {
   const char *alias;
   const char *type;
@@ -828,7 +841,7 @@ public:
 
 	/* Some extern variables used with handlers */
 
-extern struct show_table_type_st sys_table_types[];
+extern handlerton *sys_table_types[];
 extern const char *ha_row_type[];
 extern TYPELIB tx_isolation_typelib;
 extern TYPELIB myisam_stats_method_typelib;

sql/log.cc

@@ -38,6 +38,7 @@ ulong sync_binlog_counter= 0;
 
 static bool test_if_number(const char *str,
 			   long *res, bool allow_wildcards);
+static bool binlog_init();
 static int binlog_close_connection(THD *thd);
 static int binlog_savepoint_set(THD *thd, void *sv);
 static int binlog_savepoint_rollback(THD *thd, void *sv);
@@ -45,8 +46,12 @@ static int binlog_commit(THD *thd, bool all);
 static int binlog_rollback(THD *thd, bool all);
 static int binlog_prepare(THD *thd, bool all);
 
-static handlerton binlog_hton = {
+handlerton binlog_hton = {
   "binlog",
+  SHOW_OPTION_YES,
+  "This is a meta storage engine to represent the binlog in a transaction",
+  DB_TYPE_UNKNOWN,              /* IGNORE  for now */
+  binlog_init,
   0,
   sizeof(my_off_t),             /* savepoint size = binlog offset */
   binlog_close_connection,
@@ -71,9 +76,9 @@ static handlerton binlog_hton = {
   should be moved here.
 */
 
-handlerton *binlog_init()
+bool binlog_init()
 {
-  return &binlog_hton;
+  return false;
 }
 
 static int binlog_close_connection(THD *thd)

sql/mysql_priv.h

@@ -1069,7 +1069,6 @@ bool fn_format_relative_to_data_home(my_string to, const char *name,
 				     const char *dir, const char *extension);
 File open_binlog(IO_CACHE *log, const char *log_file_name,
                  const char **errmsg);
-handlerton *binlog_init();
 
 /* mysqld.cc */
 extern void yyerror(const char*);

sql/sql_show.cc

@@ -67,18 +67,18 @@ bool mysqld_show_storage_engines(THD *thd)
   const char *default_type_name= 
     ha_get_storage_engine((enum db_type)thd->variables.table_type);
 
-  show_table_type_st *types;
-  for (types= sys_table_types; types->type; types++)
+  handlerton **types;
+  for (types= sys_table_types; *types; types++)
   {
     protocol->prepare_for_resend();
-    protocol->store(types->type, system_charset_info);
-    const char *option_name= show_comp_option_name[(int) *types->value];
+    protocol->store((*types)->name, system_charset_info);
+    const char *option_name= show_comp_option_name[(int) (*types)->state];
 
-    if (*types->value == SHOW_OPTION_YES &&
-	!my_strcasecmp(system_charset_info, default_type_name, types->type))
+    if ((*types)->state == SHOW_OPTION_YES &&
+	!my_strcasecmp(system_charset_info, default_type_name, (*types)->name))
       option_name= "DEFAULT";
     protocol->store(option_name, system_charset_info);
-    protocol->store(types->comment, system_charset_info);
+    protocol->store((*types)->comment, system_charset_info);
     if (protocol->write())
       DBUG_RETURN(TRUE);
   }