WL#3337 (Event scheduler new architecture)

Post-review fixes. Mostly whitespace, int-to-bool return value, fixed comments


sql/Makefile.am:
  compile all submodules of Events before compiling the facade
sql/event_data_objects.cc:
  - Use initialization list
  - Clean whitespaces
  - Shorten comments
  - Fix comments
sql/event_data_objects.h:
  - Fix whitespace
sql/event_db_repository.cc:
  - Change return type from int to bool where only one error code is
    returned.
  - Don't use macros but get the maximal number of characters in a column
    from the column
  - Fix  comments
  - Make functions which has return value but it's not used - void.
sql/event_db_repository.h:
  - Methods with only one error code int -> bool return value
  - Remove declaration of fill_schema_events, a function that does not exist
sql/event_queue.cc:
  - Use initialization lists
  - Let find_n_remove_event delete the object thus making the code more robust.
    The caller could forget to destruct the object. In addition, find_n_remove_element()
    does not return a value.
  - Move check_system_tables() to class Events
  - Fix comments
sql/event_queue.h:
  - Whitespace changes
  - init_queue() should allow passing of THD
  - check_system_tables moved to class Events
  - find_n_remove_event() is now void
sql/event_scheduler.cc:
  - Initialize res before use
  - Remove end stop from message
sql/event_scheduler.h:
  Add uninitialized state. The scheduler is in it before init_scheduler()
  is called. The rationale is that otherwise state has no value before
  the call. If the system tables were damaged the scheduler won't be initialized
  but in Events::deinit() Event_scheduler::stop() will be called and this will
  touch state, generating valgrind warning at minimum.
sql/events.cc:
  - Whitespace changes
  - Fix comments
  - Make methods which have only one error code be bool instead of int
  - Create temporarily a THD to be used for the initialization of Event_queue
  - Event_queue::check_system_tables() moved to Events::check_system_tables
  - is_started() is renamed to is_execution_of_events_started()
sql/events.h:
  - Whitespace changes
  - When a method returns only one error code it should be bool, not int
  - is_started() renamed to is_execution_of_events_started()
sql/set_var.cc:
  is_started() is renamed to is_execution_of_events_started()
sql/sql_db.cc:
  The return code is not used, thus don't return anything and drop_schema_events()
  is now void.
sql/sql_yacc.yy:
  - Fix comments
  - Remove unneeded initialization which is performed in lex_init()
sql/share/errmsg.txt:
  New error message
sql/table.cc:
  - Fix comments
  - make table_check_intact() accespt const *table_def
sql/table.h:
  Make table_check_intact() accespt const *table_def

sql/events.h

@@ -42,59 +42,59 @@ sortcmp_lex_string(LEX_STRING s, LEX_STRING t, CHARSET_INFO *cs);
 class Events
 {
 public:
-  friend class Event_queue_element;
   /*
     Quite NOT the best practice and will be removed once
     Event_timed::drop() and Event_timed is fixed not do drop directly
     or other scheme will be found.
   */
+  friend class Event_queue_element;
 
   static ulong opt_event_scheduler;
   static TYPELIB opt_typelib;
 
   bool
   init();
-  
+
   void
   deinit();
 
   void
   init_mutexes();
-  
+
   void
   destroy_mutexes();
 
   bool
   start_execution_of_events();
-  
+
   bool
   stop_execution_of_events();
-  
-  bool
-  is_started();
 
-  static Events*
+  bool
+  is_execution_of_events_started();
+
+  static Events *
   get_instance();
 
-  int
+  bool
   create_event(THD *thd, Event_parse_data *parse_data, bool if_exists,
                uint *rows_affected);
 
-  int
+  bool
   update_event(THD *thd, Event_parse_data *parse_data, sp_name *rename_to,
                uint *rows_affected);
 
-  int
+  bool
   drop_event(THD *thd, LEX_STRING dbname, LEX_STRING name, bool if_exists,
              uint *rows_affected, bool only_from_disk);
 
-  int
+  void
   drop_schema_events(THD *thd, char *db);
 
   int
   open_event_table(THD *thd, enum thr_lock_type lock_type, TABLE **table);
 
-  int
+  bool
   show_create_event(THD *thd, LEX_STRING dbname, LEX_STRING name);
 
   /* Needed for both SHOW CREATE EVENT and INFORMATION_SCHEMA */
@@ -104,23 +104,28 @@ public:
 
   static int
   fill_schema_events(THD *thd, TABLE_LIST *tables, COND * /* cond */);
-  
+
   bool
   dump_internal_status(THD *thd);
 
 private:
+  bool
+  check_system_tables(THD *thd);
+
   /* Singleton DP is used */
-  Events(){}
+  Events();
   ~Events(){}
 
   /* Singleton instance */
   static Events singleton;
 
   Event_queue         *event_queue;
-  Event_scheduler  *scheduler;
+  Event_scheduler     *scheduler;
   Event_db_repository *db_repository;
 
-  pthread_mutex_t LOCK_event_metadata;  
+  pthread_mutex_t LOCK_event_metadata;
+
+  bool check_system_tables_error;
 
   /* Prevent use of these */
   Events(const Events &);