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.

1 files changed, 38 insertions, 13 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();