Added version of lex_string_eq that compares with const char *

Change all my_stcasecmp() calls that uses lexical keywords to use
lex_string_eq. This is faster as we only call strcasecmp() for
strings of different lengths.

Removed not used function lex_string_syseq()

sql/item_func.cc

@@ -62,9 +62,9 @@
 
 bool check_reserved_words(const LEX_CSTRING *name)
 {
-  if (!my_strcasecmp(system_charset_info, name->str, "GLOBAL") ||
+  if (lex_string_eq(name, STRING_WITH_LEN("GLOBAL")) ||
-      !my_strcasecmp(system_charset_info, name->str, "LOCAL") ||
+      lex_string_eq(name, STRING_WITH_LEN("LOCAL")) ||
-      !my_strcasecmp(system_charset_info, name->str, "SESSION"))
+      lex_string_eq(name, STRING_WITH_LEN("SESSION")))
     return TRUE;
   return FALSE;
 }

sql/lex_string.h

@@ -21,6 +21,7 @@
 typedef struct st_mysql_const_lex_string LEX_CSTRING;
 
 /* Functions to compare if two lex strings are equal */
+
 static inline bool lex_string_cmp(CHARSET_INFO *charset, const LEX_CSTRING *a,
                                   const LEX_CSTRING *b)
 {
@@ -30,6 +31,7 @@ static inline bool lex_string_cmp(CHARSET_INFO *charset, const LEX_CSTRING *a,
 /*
   Compare to LEX_CSTRING's and return 0 if equal
 */
+
 static inline bool cmp(const LEX_CSTRING *a, const LEX_CSTRING *b)
 {
   return (a->length != b->length ||
@@ -40,6 +42,7 @@ static inline bool cmp(const LEX_CSTRING *a, const LEX_CSTRING *b)
   Compare if two LEX_CSTRING are equal. Assumption is that
   character set is ASCII (like for plugin names)
 */
+
 static inline bool lex_string_eq(const LEX_CSTRING *a, const LEX_CSTRING *b)
 {
   if (a->length != b->length)
@@ -48,12 +51,15 @@ static inline bool lex_string_eq(const LEX_CSTRING *a, const LEX_CSTRING *b)
 }
 
 /*
-  Compare if two LEX_CSTRING are equal in system character set
+  To be used when calling lex_string_eq with STRING_WITH_LEN() as second
-  (field names, user variables, etc - but *not* table names)
+  argument
 */
-static inline bool lex_string_syseq(const LEX_CSTRING *a, const LEX_CSTRING *b)
+
+static inline bool lex_string_eq(const LEX_CSTRING *a, const char *b, size_t b_length)
 {
-  return lex_string_cmp(system_charset_info, a, b) == 0;
+  if (a->length != b_length)
+    return 0;                                   /* Different */
+  return strcasecmp(a->str, b) == 0;
 }
 
 #endif /* LEX_STRING_INCLUDED */

sql/sql_alter.cc

@@ -54,11 +54,11 @@ Alter_info::Alter_info(const Alter_info &rhs, MEM_ROOT *mem_root)
 bool Alter_info::set_requested_algorithm(const LEX_CSTRING *str)
 {
   // To avoid adding new keywords to the grammar, we match strings here.
-  if (!my_strcasecmp(system_charset_info, str->str, "INPLACE"))
+  if (lex_string_eq(str, STRING_WITH_LEN("INPLACE")))
     requested_algorithm= ALTER_TABLE_ALGORITHM_INPLACE;
-  else if (!my_strcasecmp(system_charset_info, str->str, "COPY"))
+  else if (lex_string_eq(str, STRING_WITH_LEN("COPY")))
     requested_algorithm= ALTER_TABLE_ALGORITHM_COPY;
-  else if (!my_strcasecmp(system_charset_info, str->str, "DEFAULT"))
+  else if (lex_string_eq(str, STRING_WITH_LEN("DEFAULT")))
     requested_algorithm= ALTER_TABLE_ALGORITHM_DEFAULT;
   else
     return true;
@@ -69,13 +69,13 @@ bool Alter_info::set_requested_algorithm(const LEX_CSTRING *str)
 bool Alter_info::set_requested_lock(const LEX_CSTRING *str)
 {
   // To avoid adding new keywords to the grammar, we match strings here.
-  if (!my_strcasecmp(system_charset_info, str->str, "NONE"))
+  if (lex_string_eq(str, STRING_WITH_LEN("NONE")))
     requested_lock= ALTER_TABLE_LOCK_NONE;
-  else if (!my_strcasecmp(system_charset_info, str->str, "SHARED"))
+  else if (lex_string_eq(str, STRING_WITH_LEN("SHARED")))
     requested_lock= ALTER_TABLE_LOCK_SHARED;
-  else if (!my_strcasecmp(system_charset_info, str->str, "EXCLUSIVE"))
+  else if (lex_string_eq(str, STRING_WITH_LEN("EXCLUSIVE")))
     requested_lock= ALTER_TABLE_LOCK_EXCLUSIVE;
-  else if (!my_strcasecmp(system_charset_info, str->str, "DEFAULT"))
+  else if (lex_string_eq(str, STRING_WITH_LEN("DEFAULT")))
     requested_lock= ALTER_TABLE_LOCK_DEFAULT;
   else
     return true;

sql/sql_lex.cc

@@ -7038,9 +7038,9 @@ Item *LEX::create_item_ident_sp(THD *thd, Lex_ident_sys_st *name,
 
   if (thd->variables.sql_mode & MODE_ORACLE)
   {
-    if (!my_strcasecmp(system_charset_info, name->str, "SQLCODE"))
+    if (lex_string_eq(name, STRING_WITH_LEN("SQLCODE")))
       return new (thd->mem_root) Item_func_sqlcode(thd);
-    if (!my_strcasecmp(system_charset_info, name->str, "SQLERRM"))
+    if (lex_string_eq(name, STRING_WITH_LEN("SQLERRM")))
       return new (thd->mem_root) Item_func_sqlerrm(thd);
   }
   return create_item_ident_nosp(thd, name);

sql/sql_trigger.cc

@@ -431,7 +431,7 @@ bool mysql_create_or_drop_trigger(THD *thd, TABLE_LIST *tables, bool create)
   /*
     We don't allow creating triggers on tables in the 'mysql' schema
   */
-  if (create && !my_strcasecmp(system_charset_info, "mysql", tables->db.str))
+  if (create && lex_string_eq(&tables->db, STRING_WITH_LEN("mysql")))
   {
     my_error(ER_NO_TRIGGERS_ON_SYSTEM_SCHEMA, MYF(0));
     DBUG_RETURN(TRUE);

sql/sql_yacc.yy

@@ -14106,9 +14106,9 @@ opt_format_json:
           /* empty */ {}
         | FORMAT_SYM '=' ident_or_text
           {
-            if (!my_strcasecmp(system_charset_info, $3.str, "JSON"))
+            if (lex_string_eq(&$3, STRING_WITH_LEN("JSON")))
               Lex->explain_json= true;
-            else if (!my_strcasecmp(system_charset_info, $3.str, "TRADITIONAL"))
+            else if (lex_string_eq(&$3, STRING_WITH_LEN("TRADITIONAL")))
               DBUG_ASSERT(Lex->explain_json==false);
             else
               my_yyabort_error((ER_UNKNOWN_EXPLAIN_FORMAT, MYF(0), "EXPLAIN",
@@ -17466,9 +17466,9 @@ opt_format_xid:
          /* empty */ { $$= false; }
         | FORMAT_SYM '=' ident_or_text
           {
-            if (!my_strcasecmp(system_charset_info, $3.str, "SQL"))
+            if (lex_string_eq(&$3, STRING_WITH_LEN("SQL")))
               $$= true;
-            else if (!my_strcasecmp(system_charset_info, $3.str, "RAW"))
+            else if (lex_string_eq(&$3, STRING_WITH_LEN("RAW")))
               $$= false;
             else
             {

sql/sql_yacc_ora.yy

@@ -13848,9 +13848,9 @@ opt_format_json:
           /* empty */ {}
         | FORMAT_SYM '=' ident_or_text
           {
-            if (!my_strcasecmp(system_charset_info, $3.str, "JSON"))
+            if (lex_string_eq(&$3, STRING_WITH_LEN("JSON")))
               Lex->explain_json= true;
-            else if (!my_strcasecmp(system_charset_info, $3.str, "TRADITIONAL"))
+            else if (lex_string_eq(&$3, STRING_WITH_LEN("TRADITIONAL")))
               DBUG_ASSERT(Lex->explain_json==false);
             else
               my_yyabort_error((ER_UNKNOWN_EXPLAIN_FORMAT, MYF(0), "EXPLAIN",
@@ -17332,9 +17332,9 @@ opt_format_xid:
          /* empty */ { $$= false; }
         | FORMAT_SYM '=' ident_or_text
           {
-            if (!my_strcasecmp(system_charset_info, $3.str, "SQL"))
+            if (lex_string_eq(&$3, STRING_WITH_LEN("SQL")))
               $$= true;
-            else if (!my_strcasecmp(system_charset_info, $3.str, "RAW"))
+            else if (lex_string_eq(&$3, STRING_WITH_LEN("RAW")))
               $$= false;
             else
             {