WL#3337 (Event scheduler new architecture)

This is a post-review patch.

Fixes the typelib implementation, available only in 5.1.11.

--event-scheduler cmdline : DISABLED | ON | OFF | 0 | 1
DISABLED - makes the scheduler unavailable during the server run
(ON|1)-  When the server is started the scheduler will be started. It can
         be stopped and restarted by setting appropriate values to
         GLOBAL event_scheduler
(OFF|0)- When the server is started, the scheduler won't be started. It
         can be started and again stopped by setting appropriate values to
         GLOBAL event_scheduler. _DEFAULT_ value

The GLOBAL variable event_scheduler can have the following values:
OFF | ON | 0 | 1
DISABLED is not possible and every attempt will end with an error that
it's not a valid value for the variable.
OFF | 0 - This is the pre-5.1.11 behavior - The scheduler stops, if not
          already stopped, and can be started again  by setting
          the value of the variable to ON|1.
ON | 1  - This is the pre-5.1.11 behavior - The scheduler starts, if not
          already started, and can be stopped again by setting the value
          of the variable to OFF|0.


mysql-test/r/events.result:
  update result
mysql-test/r/events_bugs.result:
  update result
mysql-test/r/events_logs_tests.result:
  update result
mysql-test/r/events_restart_phase1.result:
  update result
mysql-test/r/events_restart_phase3.result:
  update result
mysql-test/r/events_scheduling.result:
  update result
mysql-test/r/events_stress.result:
  update result
mysql-test/t/events.test:
  update test:
  2 -> off
  1 -> on
mysql-test/t/events_bugs.test:
  update test:
  2 -> off
  1 -> on
mysql-test/t/events_logs_tests.test:
  update test:
  2 -> off
  1 -> on
mysql-test/t/events_restart_phase1.test:
  update test:
  2 -> off
  1 -> on
mysql-test/t/events_restart_phase2-master.opt:
  update master file : 1 => on
mysql-test/t/events_scheduling.test:
  update test:
  2 -> off
  1 -> on
  
  add tests for event_scheduler global variable representation from
  SHOW VARIABLES.
mysql-test/t/events_stress.test:
  update test:
  2 -> off
  1 -> on
sql/events.cc:
  Implement two different TYPELIBs for --event-scheduler cmd line
  option and for GLOBAL variable event_scheduler
  
  --event-scheduler cmdline : DISABLED | ON | OFF | 0 | 1
  DISABLED - makes the scheduler unavailable during the server run
  (ON|1)-  When the server is started the scheduler will be started. It can
           be stopped and restarted by setting appropriate values to
           GLOBAL event_scheduler
  (OFF|0)- When the server is started, the scheduler won't be started. It
           can be started and again stopped by setting appropriate values to
           GLOBAL event_scheduler. _DEFAULT_ value
  
  The GLOBAL variable event_scheduler can have the following values:
  OFF | ON | 0 | 1
  DISABLED is not possible and every attempt will end with an error that
  it's not a valid value for the variable.
  OFF | 0 - This is the pre-5.1.11 behavior - The scheduler stops, if not
            already stopped, and can be started again  by setting
            the value of the variable to ON|1.
  ON | 1  - This is the pre-5.1.11 behavior - The scheduler starts, if not
            already started, and can be stopped again by setting the value
            of the variable to OFF|0.
sql/events.h:
  additional TYPELIB for GLOBAL event_scheduler
sql/mysqld.cc:
  --event-scheduler should be checked against a TYPELIB and
  therefore should be GET_STR, as well as we make the parameter optional.
  When not provided OFF|0 is used.
sql/set_var.cc:
  Implement typelib for event_scheduler variable.
  If allows both INT_RESULT -> 0 | 1 
  and STRING_RESULT -> OFF | ON
  The variable is shown as DISABLED | ON | OFF
sql/set_var.h:
  Implement typelib, which expects both STRING and INT,
  for event_scheduler.

5 files changed, 103 insertions, 44 deletions

diff --git a/sql/events.cc b/sql/events.cc
index f4b9b05179d..931ba17341f 100644
--- a/sql/events.cc
+++ b/sql/events.cc
@@ -59,17 +59,39 @@
   eligible for execution.
 */
 
-const char *event_scheduler_state_names[]=
-    { "OFF", "0", "ON", "1", "SUSPEND", "2", NullS };
+/*
+  Keep the order of the first to as in var_typelib
+  sys_var_event_scheduler::value_ptr() references this array. Keep in
+  mind!
+*/
+static const char *opt_event_scheduler_state_names[]=
+    { "OFF", "ON", "0", "1", "DISABLED", NullS };
 
 TYPELIB Events::opt_typelib=
 {
-  array_elements(event_scheduler_state_names)-1,
+  array_elements(opt_event_scheduler_state_names)-1,
   "",
-  event_scheduler_state_names,
+  opt_event_scheduler_state_names,
   NULL
 };
 
+
+/*
+  The order should not be changed. We consider OFF to be equivalent of INT 0
+  And ON of 1. If OFF & ON are interchanged the logic in
+  sys_var_event_scheduler::update() will be broken!
+*/
+static const char *var_event_scheduler_state_names[]= { "OFF", "ON", NullS };
+
+TYPELIB Events::var_typelib=
+{
+  array_elements(var_event_scheduler_state_names)-1,
+  "",
+  var_event_scheduler_state_names,
+  NULL
+};
+
+
 static
 Event_queue events_event_queue;
 
@@ -81,7 +103,8 @@ Event_db_repository events_event_db_repository;
 
 Events Events::singleton;
 
-ulong Events::opt_event_scheduler= 2;
+enum Events::enum_opt_event_scheduler Events::opt_event_scheduler=
+     Events::EVENTS_OFF;
 
 
 /*
@@ -607,6 +630,9 @@ Events::init()
   bool res= FALSE;
   DBUG_ENTER("Events::init");
 
+  if (opt_event_scheduler == Events::EVENTS_DISABLED)
+    DBUG_RETURN(FALSE);
+
   /* We need a temporary THD during boot */
   if (!(thd= new THD()))
   {
@@ -637,12 +663,10 @@ Events::init()
   }
   scheduler->init_scheduler(event_queue);
 
-  if (opt_event_scheduler)
-  {
-    DBUG_ASSERT(opt_event_scheduler == 1 || opt_event_scheduler == 2);
-    if (opt_event_scheduler == 1)
-      res= scheduler->start();
-  }
+  DBUG_ASSERT(opt_event_scheduler == Events::EVENTS_ON ||
+              opt_event_scheduler == Events::EVENTS_OFF);
+  if (opt_event_scheduler == Events::EVENTS_ON)
+    res= scheduler->start();
 
 end:
   delete thd;
@@ -667,10 +691,11 @@ void
 Events::deinit()
 {
   DBUG_ENTER("Events::deinit");
-
-  if (likely(!check_system_tables_error))
+  if (likely(!check_system_tables_error) &&
+      scheduler->get_state() > Event_scheduler::UNINITIALIZED)
   {
     scheduler->stop();
+    DBUG_ASSERT(scheduler->get_state() == Event_scheduler::INITIALIZED);  
     scheduler->deinit_scheduler();
 
     event_queue->deinit_queue();
diff --git a/sql/events.h b/sql/events.h
index 737044ad298..9a820b8521e 100644
--- a/sql/events.h
+++ b/sql/events.h
@@ -48,9 +48,18 @@ public:
     or other scheme will be found.
   */
   friend class Event_queue_element;
-
-  static ulong opt_event_scheduler;
+  
+  /* The order should match the order in opt_typelib */
+  enum enum_opt_event_scheduler
+  {
+    EVENTS_OFF= 0,
+    EVENTS_ON= 1,
+    EVENTS_DISABLED= 5,
+  };
+
+  static enum_opt_event_scheduler opt_event_scheduler;
   static TYPELIB opt_typelib;
+  static TYPELIB var_typelib;
 
   bool
   init();
diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index 58697202461..b8626623b59 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -5072,9 +5072,9 @@ Disable with --skip-bdb (will save memory).",
    (gptr*) &global_system_variables.engine_condition_pushdown,
    (gptr*) &global_system_variables.engine_condition_pushdown,
    0, GET_BOOL, NO_ARG, 0, 0, 0, 0, 0, 0},
+  /* See how it's handled in get_one_option() */
   {"event-scheduler", OPT_EVENT_SCHEDULER, "Enable/disable the event scheduler.",
-   (gptr*) &Events::opt_event_scheduler, (gptr*) &Events::opt_event_scheduler, 0, GET_ULONG,
-    REQUIRED_ARG, 2/*default*/, 0/*min-value*/, 2/*max-value*/, 0, 0, 0},
+   NULL,  NULL, 0, GET_STR, OPT_ARG, 0, 0, 0, 0, 0, 0},
   {"exit-info", 'T', "Used for debugging;  Use at your own risk!", 0, 0, 0,
    GET_LONG, OPT_ARG, 0, 0, 0, 0, 0, 0},
   {"external-locking", OPT_USE_LOCKING, "Use system (external) locking (disabled by default).  With this option enabled you can run myisamchk to test (not repair) tables while the MySQL server is running. Disable with --skip-external-locking.",
@@ -7423,20 +7423,33 @@ get_one_option(int optid, const struct my_option *opt __attribute__((unused)),
 #endif
   case OPT_EVENT_SCHEDULER:
     if (!argument)
-      Events::opt_event_scheduler= 2;
+      Events::opt_event_scheduler= Events::EVENTS_DISABLED;
     else
     {
       int type;
-      if ((type=find_type(argument, &Events::opt_typelib, 1)) <= 0)
-      {
-	fprintf(stderr,"Unknown option to event-scheduler: %s\n",argument);
-	exit(1);
-      }
       /* 
-        type=  1     2      3   4     5    6
-             (OFF |  0) - (ON | 1) - (2 | SUSPEND)
+        type=     5          1   2      3   4
+             (DISABLE ) - (OFF | ON) - (0 | 1)
       */
-      Events::opt_event_scheduler= (type-1) / 2;
+      switch ((type=find_type(argument, &Events::opt_typelib, 1))) {
+      case 0:
+	fprintf(stderr, "Unknown option to event-scheduler: %s\n",argument);
+	exit(1);
+      case 5: /* OPT_DISABLED */
+        Events::opt_event_scheduler= Events::EVENTS_DISABLED;
+        break;
+      case 2: /* OPT_ON  */
+      case 4: /* 1   */
+        Events::opt_event_scheduler= Events::EVENTS_ON;
+        break;
+      case 1: /* OPT_OFF */
+      case 3: /*  0  */
+        Events::opt_event_scheduler= Events::EVENTS_OFF;
+        break;
+      default:
+        DBUG_ASSERT(0);
+        unireg_abort(1);
+      }
     }
     break;
   case (int) OPT_SKIP_NEW:
diff --git a/sql/set_var.cc b/sql/set_var.cc
index f10df7fa6f8..d2764e13ae3 100644
--- a/sql/set_var.cc
+++ b/sql/set_var.cc
@@ -3914,6 +3914,7 @@ bool sys_var_thd_dbug::update(THD *thd, set_var *var)
   return 0;
 }
 
+
 byte *sys_var_thd_dbug::value_ptr(THD *thd, enum_var_type type, LEX_STRING *b)
 {
   char buf[256];
@@ -3925,6 +3926,12 @@ byte *sys_var_thd_dbug::value_ptr(THD *thd, enum_var_type type, LEX_STRING *b)
 }
 
 
+bool sys_var_event_scheduler::check(THD *thd, set_var *var)
+{
+  return check_enum(thd, var, &Events::var_typelib);
+}
+
+
 /*
    The update method of the global variable event_scheduler.
    If event_scheduler is switched from 0 to 1 then the scheduler main
@@ -3946,29 +3953,27 @@ sys_var_event_scheduler::update(THD *thd, set_var *var)
   int res;
   /* here start the thread if not running. */
   DBUG_ENTER("sys_var_event_scheduler::update");
-  if (Events::opt_event_scheduler == 0)
+  if (Events::opt_event_scheduler == Events::EVENTS_DISABLED)
   {
-    my_error(ER_OPTION_PREVENTS_STATEMENT, MYF(0), "--event-scheduler=0");
+    my_error(ER_OPTION_PREVENTS_STATEMENT, MYF(0), "--event-scheduler=DISABLED");
     DBUG_RETURN(TRUE);
   }
 
   DBUG_PRINT("new_value", ("%lu", (bool)var->save_result.ulong_value));
 
-  if (var->save_result.ulonglong_value < 1 ||
-      var->save_result.ulonglong_value > 2)
-  {
-    char buf[64];
-    my_error(ER_WRONG_VALUE_FOR_VAR, MYF(0), "event_scheduler",
-             llstr(var->save_result.ulonglong_value, buf));
-    DBUG_RETURN(TRUE);
-  }
-  if (var->save_result.ulonglong_value == 1)
+  Item_result var_type= var->value->result_type();
+
+  if (var->save_result.ulong_value == Events::EVENTS_ON)
     res= Events::get_instance()->start_execution_of_events();
-  else
+  else if (var->save_result.ulong_value == Events::EVENTS_OFF)
     res= Events::get_instance()->stop_execution_of_events();
-
+  else
+  {
+    DBUG_ASSERT(0);
+  }
   if (res)
     my_error(ER_EVENT_SET_VAR_ERROR, MYF(0));
+
   DBUG_RETURN((bool) res);
 }
 
@@ -3976,14 +3981,15 @@ sys_var_event_scheduler::update(THD *thd, set_var *var)
 byte *sys_var_event_scheduler::value_ptr(THD *thd, enum_var_type type,
                                          LEX_STRING *base)
 {
-  if (Events::opt_event_scheduler == 0)
-    thd->sys_var_tmp.long_value= 0;
+  int state;
+  if (Events::opt_event_scheduler == Events::EVENTS_DISABLED)
+    state= Events::EVENTS_DISABLED;              // This should be DISABLED
   else if (Events::get_instance()->is_execution_of_events_started())
-    thd->sys_var_tmp.long_value= 1;
+    state= Events::EVENTS_ON;                    // This should be ON
   else
-    thd->sys_var_tmp.long_value= 2;
+    state= Events::EVENTS_OFF;                   // This should be OFF
 
-  return (byte*) &thd->sys_var_tmp;
+  return (byte*) Events::opt_typelib.type_names[state];
 }
 
 
diff --git a/sql/set_var.h b/sql/set_var.h
index a63bcc4a55d..01669b378e1 100644
--- a/sql/set_var.h
+++ b/sql/set_var.h
@@ -932,6 +932,12 @@ public:
     sys_var_long_ptr(name_arg, NULL, NULL) {};
   bool update(THD *thd, set_var *var);
   byte *value_ptr(THD *thd, enum_var_type type, LEX_STRING *base);
+  SHOW_TYPE type() { return SHOW_CHAR; }
+  bool check(THD *thd, set_var *var);
+  bool check_update_type(Item_result type)
+  {
+    return type != STRING_RESULT && type != INT_RESULT;
+  }
 };
 
 #ifdef HAVE_ROW_BASED_REPLICATION