1. sys_variables[] array is removed.

2. All have_xxx variables are now selectable.


sql/set_var.cc:
  1. sys_have_xxx variables added.
  2. Removed sys_var *sys_variables[] array as we don't need it any more.
  3. void set_var_init() changed to use sys_var_xxx chain insted of sys_variables[] array.
sql/set_var.h:
  1. add_sys_var() method added to the sys_var class. It's called from constructors
  to chain all successor objects. The first one is stored in the 'static sys_var *first'.
  The total number of variables is in the 'static uint sys_vars'. Each sys_var successor object
  has the 'sys_var *next' pointer to the next one in the chain. 
  2. sys_var_have_variable class introduced to make all have_xxx variables selectable.
sql/sql_lex.cc:
  trg_new_row_fake_var(0, 0) replaced with '(sys_var*) 0x01' as we don't want to have such fake variables in the sys_var_xxx chain.
sql/sql_lex.h:
  Proper use of the changed trg_new_row_fake_var.
sql/sql_yacc.yy:
  Proper use of the changed trg_new_row_fake_var.

1 files changed, 35 insertions, 2 deletions

diff --git a/sql/set_var.h b/sql/set_var.h
index c9566afed65..c1d91bb1973 100644
--- a/sql/set_var.h
+++ b/sql/set_var.h
@@ -39,6 +39,9 @@ typedef byte *(*sys_value_ptr_func)(THD *thd);
 class sys_var
 {
 public:
+  static sys_var *first;
+  static uint sys_vars;
+  sys_var *next;
   struct my_option *option_limits;	/* Updated by by set_var_init() */
   uint name_length;			/* Updated by by set_var_init() */
   const char *name;
@@ -48,12 +51,18 @@ public:
   sys_var(const char *name_arg)
     :name(name_arg), after_update(0)
     , no_support_one_shot(1)
-    {}
+  { add_sys_var(); }
   sys_var(const char *name_arg,sys_after_update_func func)
     :name(name_arg), after_update(func)
     , no_support_one_shot(1)
-  {}
+  { add_sys_var(); }
   virtual ~sys_var() {}
+  void add_sys_var()
+  {
+    next= first;
+    first= this;
+    sys_vars++;
+  }
   virtual bool check(THD *thd, set_var *var);
   bool check_enum(THD *thd, set_var *var, TYPELIB *enum_names);
   bool check_set(THD *thd, set_var *var, TYPELIB *enum_names);
@@ -701,6 +710,30 @@ public:
   bool is_readonly() const { return 1; }
 };
 
+
+class sys_var_have_variable: public sys_var
+{
+  SHOW_COMP_OPTION *have_variable;
+
+public:
+  sys_var_have_variable(const char *variable_name,
+                        SHOW_COMP_OPTION *have_variable_arg):
+    sys_var(variable_name),
+    have_variable(have_variable_arg)
+  { }
+  byte *value_ptr(THD *thd, enum_var_type type, LEX_STRING *base)
+  {
+    return (byte*) show_comp_option_name[*have_variable];
+  }
+  bool update(THD *thd, set_var *var) { return 1; }
+  bool check_default(enum_var_type type) { return 1; }
+  bool check_type(enum_var_type type) { return type != OPT_GLOBAL; }
+  bool check_update_type(Item_result type) { return 1; }
+  SHOW_TYPE type() { return SHOW_CHAR; }
+  bool is_readonly() const { return 1; }
+};
+
+
 class sys_var_thd_time_zone :public sys_var_thd
 {
 public: