MDEV-31992 Automatic conversion from LEX_STRING to LEX_CSTRING

- Adding automatic conversion operator from LEX_STRING to LEX_CSTRING
  Now a LEX_STRING can be passed directly to any function expecting
  a LEX_CSTRING parameter passed by value or by reference.
- Removing a number of duplicate methods accepting LEX_STRING.
  Now the code used the LEX_CSTRING version.

include/mysql/plugin_audit.h.pp

@@ -301,18 +301,22 @@ void my_sha512_input(void *context, const unsigned char *buf, size_t len);
 void my_sha512_result(void *context, unsigned char *digest);
 }
 extern "C" {
-struct st_mysql_lex_string
-{
-  char *str;
-  size_t length;
-};
-typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 struct st_mysql_const_lex_string
 {
   const char *str;
   size_t length;
 };
 typedef struct st_mysql_const_lex_string MYSQL_CONST_LEX_STRING;
+struct st_mysql_lex_string
+{
+  char *str;
+  size_t length;
+  operator struct st_mysql_const_lex_string() const
+  {
+    return {str, length};
+  }
+};
+typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 extern struct thd_alloc_service_st {
   void *(*thd_alloc_func)(const THD*, size_t);
   void *(*thd_calloc_func)(const THD*, size_t);

include/mysql/plugin_auth.h.pp

@@ -301,18 +301,22 @@ void my_sha512_input(void *context, const unsigned char *buf, size_t len);
 void my_sha512_result(void *context, unsigned char *digest);
 }
 extern "C" {
-struct st_mysql_lex_string
-{
-  char *str;
-  size_t length;
-};
-typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 struct st_mysql_const_lex_string
 {
   const char *str;
   size_t length;
 };
 typedef struct st_mysql_const_lex_string MYSQL_CONST_LEX_STRING;
+struct st_mysql_lex_string
+{
+  char *str;
+  size_t length;
+  operator struct st_mysql_const_lex_string() const
+  {
+    return {str, length};
+  }
+};
+typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 extern struct thd_alloc_service_st {
   void *(*thd_alloc_func)(const THD*, size_t);
   void *(*thd_calloc_func)(const THD*, size_t);

include/mysql/plugin_data_type.h.pp

@@ -301,18 +301,22 @@ void my_sha512_input(void *context, const unsigned char *buf, size_t len);
 void my_sha512_result(void *context, unsigned char *digest);
 }
 extern "C" {
-struct st_mysql_lex_string
-{
-  char *str;
-  size_t length;
-};
-typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 struct st_mysql_const_lex_string
 {
   const char *str;
   size_t length;
 };
 typedef struct st_mysql_const_lex_string MYSQL_CONST_LEX_STRING;
+struct st_mysql_lex_string
+{
+  char *str;
+  size_t length;
+  operator struct st_mysql_const_lex_string() const
+  {
+    return {str, length};
+  }
+};
+typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 extern struct thd_alloc_service_st {
   void *(*thd_alloc_func)(const THD*, size_t);
   void *(*thd_calloc_func)(const THD*, size_t);

include/mysql/plugin_encryption.h.pp

@@ -301,18 +301,22 @@ void my_sha512_input(void *context, const unsigned char *buf, size_t len);
 void my_sha512_result(void *context, unsigned char *digest);
 }
 extern "C" {
-struct st_mysql_lex_string
-{
-  char *str;
-  size_t length;
-};
-typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 struct st_mysql_const_lex_string
 {
   const char *str;
   size_t length;
 };
 typedef struct st_mysql_const_lex_string MYSQL_CONST_LEX_STRING;
+struct st_mysql_lex_string
+{
+  char *str;
+  size_t length;
+  operator struct st_mysql_const_lex_string() const
+  {
+    return {str, length};
+  }
+};
+typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 extern struct thd_alloc_service_st {
   void *(*thd_alloc_func)(const THD*, size_t);
   void *(*thd_calloc_func)(const THD*, size_t);

include/mysql/plugin_ftparser.h.pp

@@ -301,18 +301,22 @@ void my_sha512_input(void *context, const unsigned char *buf, size_t len);
 void my_sha512_result(void *context, unsigned char *digest);
 }
 extern "C" {
-struct st_mysql_lex_string
-{
-  char *str;
-  size_t length;
-};
-typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 struct st_mysql_const_lex_string
 {
   const char *str;
   size_t length;
 };
 typedef struct st_mysql_const_lex_string MYSQL_CONST_LEX_STRING;
+struct st_mysql_lex_string
+{
+  char *str;
+  size_t length;
+  operator struct st_mysql_const_lex_string() const
+  {
+    return {str, length};
+  }
+};
+typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 extern struct thd_alloc_service_st {
   void *(*thd_alloc_func)(const THD*, size_t);
   void *(*thd_calloc_func)(const THD*, size_t);

include/mysql/plugin_function.h.pp

@@ -301,18 +301,22 @@ void my_sha512_input(void *context, const unsigned char *buf, size_t len);
 void my_sha512_result(void *context, unsigned char *digest);
 }
 extern "C" {
-struct st_mysql_lex_string
-{
-  char *str;
-  size_t length;
-};
-typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 struct st_mysql_const_lex_string
 {
   const char *str;
   size_t length;
 };
 typedef struct st_mysql_const_lex_string MYSQL_CONST_LEX_STRING;
+struct st_mysql_lex_string
+{
+  char *str;
+  size_t length;
+  operator struct st_mysql_const_lex_string() const
+  {
+    return {str, length};
+  }
+};
+typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 extern struct thd_alloc_service_st {
   void *(*thd_alloc_func)(const THD*, size_t);
   void *(*thd_calloc_func)(const THD*, size_t);

include/mysql/plugin_password_validation.h.pp

@@ -301,18 +301,22 @@ void my_sha512_input(void *context, const unsigned char *buf, size_t len);
 void my_sha512_result(void *context, unsigned char *digest);
 }
 extern "C" {
-struct st_mysql_lex_string
-{
-  char *str;
-  size_t length;
-};
-typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 struct st_mysql_const_lex_string
 {
   const char *str;
   size_t length;
 };
 typedef struct st_mysql_const_lex_string MYSQL_CONST_LEX_STRING;
+struct st_mysql_lex_string
+{
+  char *str;
+  size_t length;
+  operator struct st_mysql_const_lex_string() const
+  {
+    return {str, length};
+  }
+};
+typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 extern struct thd_alloc_service_st {
   void *(*thd_alloc_func)(const THD*, size_t);
   void *(*thd_calloc_func)(const THD*, size_t);

include/mysql/service_thd_alloc.h

@@ -35,19 +35,26 @@
 extern "C" {
 #endif
 
-struct st_mysql_lex_string
+struct st_mysql_const_lex_string
 {
-  char *str;
+  const char *str;
   size_t length;
 };
-typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
+typedef struct st_mysql_const_lex_string MYSQL_CONST_LEX_STRING;
 
-struct st_mysql_const_lex_string
+struct st_mysql_lex_string
 {
-  const char *str;
+  char *str;
   size_t length;
+#ifdef __cplusplus
+  // Allow automatic cast from LEX_STRING to LEX_CSTRING in c++.
+  operator struct st_mysql_const_lex_string() const
+  {
+    return {str, length};
+  }
+#endif
 };
-typedef struct st_mysql_const_lex_string MYSQL_CONST_LEX_STRING;
+typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 
 extern struct thd_alloc_service_st {
   void *(*thd_alloc_func)(const MYSQL_THD, size_t);

plugin/metadata_lock_info/metadata_lock_info.cc

@@ -70,7 +70,7 @@ int i_s_metadata_lock_info_fill_row(
     DBUG_RETURN(0);
   table->field[0]->store((longlong) mdl_ctx->get_thread_id(), TRUE);
   table->field[1]->set_notnull();
-  table->field[1]->store(mdl_ticket->get_type_name(), system_charset_info);
+  table->field[1]->store(*mdl_ticket->get_type_name(), system_charset_info);
   table->field[2]->set_null();
   table->field[3]->set_notnull();
   table->field[3]->store(

sql/field.h

@@ -981,11 +981,6 @@ class Field: public Value_source
             enum_check_fields check_level);
   int store_text(const char *to, size_t length, CHARSET_INFO *cs,
                  enum_check_fields check_level);
-  int store(const LEX_STRING *ls, CHARSET_INFO *cs)
-  {
-    DBUG_ASSERT(ls->length < UINT_MAX32);
-    return store(ls->str, (uint) ls->length, cs);
-  }
   int store(const LEX_CSTRING *ls, CHARSET_INFO *cs)
   {
     DBUG_ASSERT(ls->length < UINT_MAX32);

sql/sp_instr.h

@@ -514,7 +514,7 @@ class sp_instr_stmt : public sp_lex_instr
 protected:
   LEX_CSTRING get_expr_query() const override
   {
-    return LEX_CSTRING{m_query.str, m_query.length};
+    return m_query;
   }
 
   bool on_after_expr_parsing(THD *) override

sql/sql_cmd.h

@@ -133,11 +133,6 @@ class Storage_engine_name
   Storage_engine_name(const LEX_CSTRING &name)
    :m_storage_engine_name(name)
   { }
-  Storage_engine_name(const LEX_STRING &name)
-  {
-    m_storage_engine_name.str= name.str;
-    m_storage_engine_name.length= name.length;
-  }
   bool resolve_storage_engine_with_error(THD *thd,
                                          handlerton **ha,
                                          bool tmp_table);

sql/sql_string.h

@@ -1052,13 +1052,6 @@ class String: public Charset, public Binary_string
   }
 
   // Append with optional character set conversion from ASCII (e.g. to UCS2)
-  bool append(const LEX_STRING *ls)
-  {
-    DBUG_ASSERT(ls->length < UINT_MAX32 &&
-                ((ls->length == 0 && !ls->str) ||
-                 ls->length == strlen(ls->str)));
-    return append(ls->str, (uint32) ls->length);
-  }
   bool append(const LEX_CSTRING *ls)
   {
     DBUG_ASSERT(ls->length < UINT_MAX32 &&

sql/vers_string.h

@@ -57,9 +57,6 @@ struct Lex_cstring_with_compare : public Lex_cstring
   Lex_cstring_with_compare(const char *_str, size_t _len) :
     Lex_cstring(_str, _len)
   { }
-  Lex_cstring_with_compare(const LEX_STRING src) :
-    Lex_cstring(src.str, src.length)
-  { }
   Lex_cstring_with_compare(const LEX_CSTRING src) : Lex_cstring(src.str, src.length)
   { }
   Lex_cstring_with_compare(const char *_str) : Lex_cstring(_str, strlen(_str))

storage/spider/spd_malloc.cc

@@ -861,7 +861,7 @@ bool spider_string::append(
   DBUG_ASSERT(mem_calc_inited);
   DBUG_ASSERT((!current_alloc_mem && !str.is_alloced()) ||
     current_alloc_mem == str.alloced_length());
-  bool res = str.append(ls);
+  bool res = str.append(*ls);
   SPIDER_STRING_CALC_MEM;
   DBUG_RETURN(res);
 }