cleanup: create LEX_USER::reset_auth()

as this is used quite often

sql/sql_acl.cc

@@ -984,7 +984,7 @@ static bool fix_user_plugin_ptr(ACL_USER *user)
 
   - if user->plugin is specified, user->auth is the plugin auth data.
   - if user->plugin is mysql_native_password or mysql_old_password,
-    user->auth if the password hash, and LEX_USER is transformed
+    user->auth is the password hash, and LEX_USER is transformed
     to match the next case (that is, user->plugin is cleared).
   - if user->plugin is NOT specified, built-in auth is assumed, that is
     mysql_native_password or mysql_old_password. In that case,
@@ -10156,9 +10156,7 @@ bool sp_grant_privileges(THD *thd, const char *sp_db, const char *sp_name,
   thd->make_lex_string(&combo->user, combo->user.str, strlen(combo->user.str));
   thd->make_lex_string(&combo->host, combo->host.str, strlen(combo->host.str));
 
-  combo->password= null_lex_str;
-  combo->plugin= empty_lex_str;
-  combo->auth= empty_lex_str;
+  combo->reset_auth();
 
   if(au)
   {

sql/sql_class.cc

@@ -5160,9 +5160,7 @@ void THD::get_definer(LEX_USER *definer, bool role)
   {
     definer->user = invoker_user;
     definer->host= invoker_host;
-    definer->password= null_lex_str;
-    definer->plugin= empty_lex_str;
-    definer->auth= empty_lex_str;
+    definer->reset_auth();
   }
   else
 #endif

sql/sql_parse.cc

@@ -8949,9 +8949,7 @@ void get_default_definer(THD *thd, LEX_USER *definer, bool role)
   }
   definer->user.length= strlen(definer->user.str);
 
-  definer->password= null_lex_str;
-  definer->plugin= empty_lex_str;
-  definer->auth= empty_lex_str;
+  definer->reset_auth();
 }
 
 
@@ -9009,7 +9007,7 @@ LEX_USER *create_definer(THD *thd, LEX_STRING *user_name, LEX_STRING *host_name)
 
   definer->user= *user_name;
   definer->host= *host_name;
-  definer->password= null_lex_str;
+  definer->reset_auth();
 
   return definer;
 }

sql/sql_yacc.yy

@@ -14139,9 +14139,7 @@ user_maybe_role:
               MYSQL_YYABORT;
             $$->user = $1;
             $$->host= null_lex_str; // User or Role, see get_current_user()
-            $$->password= null_lex_str;
-            $$->plugin= empty_lex_str;
-            $$->auth= empty_lex_str;
+            $$->reset_auth();
 
             if (check_string_char_length(&$$->user, ER_USERNAME,
                                          username_char_length,
@@ -14153,9 +14151,7 @@ user_maybe_role:
             if (!($$=(LEX_USER*) thd->alloc(sizeof(st_lex_user))))
               MYSQL_YYABORT;
             $$->user = $1; $$->host=$3;
-            $$->password= null_lex_str;
-            $$->plugin= empty_lex_str;
-            $$->auth= empty_lex_str;
+            $$->reset_auth();
 
             if (check_string_char_length(&$$->user, ER_USERNAME,
                                          username_char_length,
@@ -15417,9 +15413,7 @@ current_role:
             if (!($$=(LEX_USER*) thd->calloc(sizeof(LEX_USER))))
               MYSQL_YYABORT;
             $$->user= current_role;
-            $$->password= null_lex_str;
-            $$->plugin= empty_lex_str;
-            $$->auth= empty_lex_str;
+            $$->reset_auth();
           }
           ;
 
@@ -15438,9 +15432,7 @@ grant_role:
               MYSQL_YYABORT;
             $$->user = $1;
             $$->host= empty_lex_str;
-            $$->password= null_lex_str;
-            $$->plugin= empty_lex_str;
-            $$->auth= empty_lex_str;
+            $$->reset_auth();
 
             if (check_string_char_length(&$$->user, ER_USERNAME,
                                          username_char_length,

sql/structs.h

@@ -211,6 +211,12 @@ typedef struct	st_lex_user {
     else
       l->length= strxmov(l->str= buf, user.str, "@", host.str, NullS) - buf;
   }
+  void reset_auth()
+  {
+    password.length= plugin.length= auth.length= 0;
+    password.str= 0;
+    plugin.str= auth.str= const_cast<char*>("");
+  }
 } LEX_USER;
 
 /*