Remove String::lex_string() and String::lex_cstring()

- Better to use 'String *' directly.
- Added String::get_value(LEX_STRING*) for the few cases where we want to
  convert a String to LEX_CSTRING.

Other things:
- Use StringBuffer for some functions to avoid mallocs

18 files changed, 85 insertions, 72 deletions

diff --git a/sql/field.cc b/sql/field.cc
index a067baee460..c5d72abc526 100644
--- a/sql/field.cc
+++ b/sql/field.cc
@@ -1078,17 +1078,16 @@ Field_longstr::make_packed_sort_key_part(uchar *buff,
     *buff++=1;
   }
   uchar *end= pack_sort_string(buff, sort_field);
-  return static_cast<int>(end-buff);
+  return (uint) (end-buff);
 }
 
 
 uchar*
 Field_longstr::pack_sort_string(uchar *to, const SORT_FIELD_ATTR *sort_field)
 {
-  String buf;
+  StringBuffer<LONGLONG_BUFFER_SIZE> buf;
   val_str(&buf, &buf);
-  return to + sort_field->pack_sort_string(to, buf.lex_cstring(),
-                                           field_charset());
+  return to + sort_field->pack_sort_string(to, &buf);
 }
 
 
@@ -2106,7 +2105,7 @@ void Field::make_send_field(Send_field *field)
     field->org_table_name= field->db_name= empty_clex_str;
   if (orig_table && orig_table->alias.ptr())
   {
-    field->table_name= orig_table->alias.lex_cstring();
+    orig_table->alias.get_value(&field->table_name);
     field->org_col_name= field_name;
   }
   else
diff --git a/sql/filesort.cc b/sql/filesort.cc
index 7a3f16e0ee4..3f99bebd0cc 100644
--- a/sql/filesort.cc
+++ b/sql/filesort.cc
@@ -2546,7 +2546,6 @@ Type_handler_string_result::make_packed_sort_key_part(uchar *to, Item *item,
                                             const SORT_FIELD_ATTR *sort_field,
                                             Sort_param *param) const
 {
-  CHARSET_INFO *cs= item->collation.collation;
   bool maybe_null= item->maybe_null;
 
   if (maybe_null)
@@ -2576,7 +2575,7 @@ Type_handler_string_result::make_packed_sort_key_part(uchar *to, Item *item,
       return sort_field->original_length;
     }
   }
-  return sort_field->pack_sort_string(to, res->lex_cstring(), cs);
+  return sort_field->pack_sort_string(to, res);
 }
 
 
@@ -2932,13 +2931,12 @@ int compare_packed_sort_keys(void *sort_param,
 */
 
 uint
-SORT_FIELD_ATTR::pack_sort_string(uchar *to, const LEX_CSTRING &str,
-                                  CHARSET_INFO *cs) const
+SORT_FIELD_ATTR::pack_sort_string(uchar *to, String *str) const
 {
   uchar *orig_to= to;
   uint32 length, data_length;
-  DBUG_ASSERT(str.length <= UINT32_MAX);
-  length= (uint32)str.length;
+  DBUG_ASSERT(str->length() <= UINT32_MAX);
+  length= (uint32) str->length();
 
   if (length + suffix_length <= original_length)
     data_length= length;
@@ -2949,13 +2947,13 @@ SORT_FIELD_ATTR::pack_sort_string(uchar *to, const LEX_CSTRING &str,
   store_key_part_length(data_length + suffix_length, to, length_bytes);
   to+= length_bytes;
   // copying data length bytes to the buffer
-  memcpy(to, (uchar*)str.str, data_length);
+  memcpy(to, (uchar*)str->ptr(), data_length);
   to+= data_length;
 
-  if (cs == &my_charset_bin && suffix_length)
+  if (str->charset() == &my_charset_bin && suffix_length)
   {
     // suffix length stored in bigendian form
-    store_bigendian(str.length, to, suffix_length);
+    store_bigendian(length, to, suffix_length);
     to+= suffix_length;
   }
   return static_cast<uint>(to - orig_to);
diff --git a/sql/item.cc b/sql/item.cc
index ca23fddff34..5c662e5e6ff 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -1394,7 +1394,7 @@ bool Item::get_date_from_real(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate
 
 bool Item::get_date_from_string(THD *thd, MYSQL_TIME *to, date_mode_t mode)
 {
-  StringBuffer<40> tmp;
+  StringBuffer<MAX_DATETIME_FULL_WIDTH+1> tmp;
   Temporal::Warn_push warn(thd, field_table_or_null(), field_name_or_null(),
                            to, mode);
   Temporal_hybrid *t= new(to) Temporal_hybrid(thd, &warn, val_str(&tmp), mode);
@@ -2076,7 +2076,7 @@ Item_name_const::Item_name_const(THD *thd, Item *name_arg, Item *val):
   Item::maybe_null= TRUE;
   if (name_item->basic_const_item() &&
       (name_str= name_item->val_str(&name_buffer))) // Can't have a NULL name
-    set_name(thd, name_str->lex_cstring(), name_str->charset());
+    set_name(thd, name_str);
 }
 
 
@@ -6674,8 +6674,9 @@ int Item_string::save_in_field(Field *field, bool no_conversions)
 
 Item *Item_string::clone_item(THD *thd)
 {
-  return new (thd->mem_root)
-    Item_string(thd, name, str_value.lex_cstring(), collation.collation);
+  LEX_CSTRING val;
+  str_value.get_value(&val);
+  return new (thd->mem_root) Item_string(thd, name, val, collation.collation);
 }
 
 
diff --git a/sql/item.h b/sql/item.h
index 71d7549f72f..150d9cd215e 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -962,6 +962,10 @@ public:
 #endif
   }		/*lint -e1509 */
   void set_name(THD *thd, const char *str, size_t length, CHARSET_INFO *cs);
+  void set_name(THD *thd, String *str)
+  {
+    set_name(thd, str->ptr(), str->length(), str->charset());
+  }
   void set_name(THD *thd, const LEX_CSTRING &str,
                 CHARSET_INFO *cs= system_charset_info)
   {
@@ -4377,7 +4381,7 @@ protected:
                                    const Metadata metadata)
   {
     fix_from_value(dv, metadata);
-    set_name(thd, str_value.lex_cstring(), str_value.charset());
+    set_name(thd, &str_value);
   }
 protected:
   /* Just create an item and do not fill string representation */
diff --git a/sql/item_strfunc.cc b/sql/item_strfunc.cc
index bcc041ae9c6..7f853a73c71 100644
--- a/sql/item_strfunc.cc
+++ b/sql/item_strfunc.cc
@@ -1391,8 +1391,8 @@ String *Item_func_regexp_replace::val_str(String *str)
       !(replace= re.convert_if_needed(replace, &re.replace_converter)))
     goto err;
 
-  src= source->lex_cstring();
-  rpl= replace->lex_cstring();
+  source->get_value(&src);
+  replace->get_value(&rpl);
 
   str->length(0);
   str->set_charset(collation.collation);
diff --git a/sql/item_timefunc.cc b/sql/item_timefunc.cc
index 3425b293193..53fc7efac06 100644
--- a/sql/item_timefunc.cc
+++ b/sql/item_timefunc.cc
@@ -473,7 +473,7 @@ err:
   Create a formated date/time value in a string.
 */
 
-static bool make_date_time(const LEX_CSTRING &format, MYSQL_TIME *l_time,
+static bool make_date_time(String *format, MYSQL_TIME *l_time,
                            timestamp_type type, const MY_LOCALE *locale,
                            String *str)
 {
@@ -488,7 +488,7 @@ static bool make_date_time(const LEX_CSTRING &format, MYSQL_TIME *l_time,
   if (l_time->neg)
     str->append('-');
   
-  end= (ptr= format.str) + format.length;
+  end= (ptr= format->ptr()) + format->length();
   for (; ptr != end ; ptr++)
   {
     if (*ptr != '%' || ptr+1 == end)
@@ -1877,6 +1877,7 @@ String *Item_func_date_format::val_str(String *str)
   DBUG_ASSERT(fixed == 1);
   date_conv_mode_t mode= is_time_format ? TIME_TIME_ONLY : TIME_CONV_NONE;
   THD *thd= current_thd;
+
   if ((null_value= args[0]->get_date(thd, &l_time,
                                      Temporal::Options(mode, thd))))
     return 0;
@@ -1901,7 +1902,7 @@ String *Item_func_date_format::val_str(String *str)
 
   /* Create the result string */
   str->set_charset(collation.collation);
-  if (!make_date_time(format->lex_cstring(), &l_time,
+  if (!make_date_time(format, &l_time,
                       is_time_format ? MYSQL_TIMESTAMP_TIME :
                                        MYSQL_TIMESTAMP_DATE,
                       lc, str))
diff --git a/sql/protocol.cc b/sql/protocol.cc
index a97e0d0997d..55373bcd2b5 100644
--- a/sql/protocol.cc
+++ b/sql/protocol.cc
@@ -864,12 +864,13 @@ bool Protocol_text::store_field_metadata(const THD * thd,
     {
       Send_field_packed_extended_metadata metadata;
       metadata.pack(field);
+
       /*
         Don't apply character set conversion:
         extended metadata is a binary encoded data.
       */
-      if (store_lex_cstring(metadata.lex_cstring(), cs,
-                            MY_REPERTOIRE_UNICODE30, &my_charset_bin))
+      if (store_binary_string(&metadata, cs,
+                              MY_REPERTOIRE_UNICODE30))
         return true;
     }
     if (packet->realloc(packet->length() + 12))
diff --git a/sql/protocol.h b/sql/protocol.h
index 08f416fc9bf..18a01255708 100644
--- a/sql/protocol.h
+++ b/sql/protocol.h
@@ -149,18 +149,25 @@ public:
 
   // Various useful wrappers for the virtual store*() methods.
   // Backward wrapper for store_str()
-  bool store(const char *from, size_t length, CHARSET_INFO *cs,
-             my_repertoire_t repertoire= MY_REPERTOIRE_UNICODE30)
+  inline bool store(const char *from, size_t length, CHARSET_INFO *cs,
+                    my_repertoire_t repertoire= MY_REPERTOIRE_UNICODE30)
   {
     return store_str(from, length, cs, repertoire, character_set_results());
   }
-  bool store_lex_cstring(const LEX_CSTRING &s,
-                         CHARSET_INFO *fromcs,
-                         my_repertoire_t from_repertoire,
-                         CHARSET_INFO *tocs)
+  inline bool store_lex_cstring(const LEX_CSTRING &s,
+                                CHARSET_INFO *fromcs,
+                                my_repertoire_t from_repertoire,
+                                CHARSET_INFO *tocs)
   {
     return store_str(s.str, (uint) s.length, fromcs, from_repertoire, tocs);
   }
+  inline bool store_binary_string(Binary_string *str,
+                                  CHARSET_INFO *fromcs,
+                                  my_repertoire_t from_repertoire)
+  {
+    return store_str(str->ptr(), (uint) str->length(), fromcs, from_repertoire,
+                     &my_charset_bin);
+  }
   bool store_ident(const LEX_CSTRING &s,
                    my_repertoire_t repertoire= MY_REPERTOIRE_UNICODE30)
   {
diff --git a/sql/sp.cc b/sql/sp.cc
index 187e4b52394..3737bd11740 100644
--- a/sql/sp.cc
+++ b/sql/sp.cc
@@ -1286,7 +1286,7 @@ Sp_handler::sp_create_routine(THD *thd, const sp_head *sp) const
         if (type() == SP_TYPE_FUNCTION)
         {
           sp_returns_type(thd, retstr, sp);
-          returns= retstr.lex_cstring();
+          retstr.get_value(&returns);
         }
         goto log;
       }
@@ -1369,7 +1369,7 @@ Sp_handler::sp_create_routine(THD *thd, const sp_head *sp) const
     if (type() == SP_TYPE_FUNCTION)
     {
       sp_returns_type(thd, retstr, sp);
-      returns= retstr.lex_cstring();
+      retstr.get_value(&returns);
 
       store_failed= store_failed ||
         table->field[MYSQL_PROC_FIELD_RETURNS]->
@@ -2061,7 +2061,7 @@ Sp_handler::sp_clone_and_link_routine(THD *thd,
   if (type() == SP_TYPE_FUNCTION)
   {
     sp_returns_type(thd, retstr, sp);
-    returns= retstr.lex_cstring();
+    retstr.get_value(&returns);
   }
 
   if (sp->m_parent)
diff --git a/sql/sql_class.h b/sql/sql_class.h
index 2e388ef7d72..36f98ce1a66 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -6447,8 +6447,7 @@ struct SORT_FIELD_ATTR
   */
   bool maybe_null;
   CHARSET_INFO *cs;
-  uint pack_sort_string(uchar *to, const LEX_CSTRING &str,
-                        CHARSET_INFO *cs) const;
+  uint pack_sort_string(uchar *to, String *str) const;
   int compare_packed_fixed_size_vals(uchar *a, size_t *a_len,
                                      uchar *b, size_t *b_len);
   int compare_packed_varstrings(uchar *a, size_t *a_len,
diff --git a/sql/sql_show.cc b/sql/sql_show.cc
index 64076197cf8..f72aa23a381 100644
--- a/sql/sql_show.cc
+++ b/sql/sql_show.cc
@@ -8215,7 +8215,7 @@ int make_schemata_old_format(THD *thd, ST_SCHEMA_TABLE *schema_table)
       buffer.append(lex->wild->ptr());
       buffer.append(')');
     }
-    field->set_name(thd, buffer.lex_cstring());
+    field->set_name(thd, &buffer);
   }
   return 0;
 }
@@ -8224,7 +8224,7 @@ int make_schemata_old_format(THD *thd, ST_SCHEMA_TABLE *schema_table)
 int make_table_names_old_format(THD *thd, ST_SCHEMA_TABLE *schema_table)
 {
   char tmp[128];
-  String buffer(tmp,sizeof(tmp), thd->charset());
+  String buffer(tmp, sizeof(tmp), system_charset_info);
   LEX *lex= thd->lex;
   Name_resolution_context *context= &lex->first_select_lex()->context;
   ST_FIELD_INFO *field_info= &schema_table->fields_info[2];
@@ -8242,7 +8242,7 @@ int make_table_names_old_format(THD *thd, ST_SCHEMA_TABLE *schema_table)
   Item_field *field= new (thd->mem_root) Item_field(thd, context, field_name);
   if (add_item_to_list(thd, field))
     return 1;
-  field->set_name(thd, buffer.lex_cstring());
+  field->set_name(thd, &buffer);
   if (thd->lex->verbose)
   {
     field_info= &schema_table->fields_info[3];
diff --git a/sql/sql_string.h b/sql/sql_string.h
index 2d38f6d5d13..274b1d9a5df 100644
--- a/sql/sql_string.h
+++ b/sql/sql_string.h
@@ -222,18 +222,6 @@ public:
   inline bool is_empty() const { return (str_length == 0); }
   inline const char *ptr() const { return Ptr; }
   inline const char *end() const { return Ptr + str_length; }
-
-  LEX_STRING lex_string() const
-  {
-    LEX_STRING str = { (char*) ptr(), length() };
-    return str;
-  }
-  LEX_CSTRING lex_cstring() const
-  {
-    LEX_CSTRING skr = { ptr(), length() };
-    return skr;
-  }
-
   bool has_8bit_bytes() const
   {
     for (const char *c= ptr(), *c_end= end(); c < c_end; c++)
@@ -488,6 +476,12 @@ public:
     if (str.Alloced_length)
       Alloced_length= (uint32) (str.Alloced_length - offset);
   }
+  inline LEX_CSTRING *get_value(LEX_CSTRING *res)
+  {
+    res->str=    Ptr;
+    res->length= str_length;
+    return res;
+  }
 
   /* Take over handling of buffer from some other object */
   void reset(char *ptr_arg, size_t length_arg, size_t alloced_length_arg)
@@ -888,13 +882,13 @@ public:
   {
     return Binary_string::append_hex((const char*)src, srclen);
   }
-  bool append_introducer_and_hex(CHARSET_INFO *cs, const LEX_CSTRING &str)
+  bool append_introducer_and_hex(String *str)
   {
     return
       append(STRING_WITH_LEN("_"))   ||
-      append(cs->csname)             ||
+      append(str->charset()->csname)  ||
       append(STRING_WITH_LEN(" 0x")) ||
-      append_hex(str.str, (uint32) str.length);
+      append_hex(str->ptr(), (uint32) str->length());
   }
   bool append(IO_CACHE* file, uint32 arg_length)
   {
diff --git a/sql/sql_type.cc b/sql/sql_type.cc
index aee9b4c165c..7345b1fb529 100644
--- a/sql/sql_type.cc
+++ b/sql/sql_type.cc
@@ -8981,8 +8981,8 @@ bool Type_handler::partition_field_append_value(
     uint cnverr2= 0;
     buf2.copy(res->ptr(), res->length(), res->charset(), field_cs, &cnverr2);
     if (!cnverr2)
-      return str->append_introducer_and_hex(buf2.charset(), buf2.lex_cstring());
-    return str->append_introducer_and_hex(res->charset(), res->lex_cstring());
+      return str->append_introducer_and_hex(&buf2);
+    return str->append_introducer_and_hex(res);
   }
 
   StringBuffer<64> val(system_charset_info);
diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index d8ad3aef7c3..b42d68c26e1 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -14698,13 +14698,15 @@ literal:
         | UNDERSCORE_CHARSET hex_or_bin_String
           {
             Item_string_with_introducer *item_str;
+            LEX_CSTRING tmp;
+            $2->get_value(&tmp);
             /*
               Pass NULL as name. Name will be set in the "select_item" rule and
               will include the introducer and the original hex/bin notation.
             */
             item_str= new (thd->mem_root)
                Item_string_with_introducer(thd, null_clex_str,
-                                           $2->lex_cstring(), $1);
+                                           tmp, $1);
             if (unlikely(!item_str ||
                          !item_str->check_well_formed_result(true)))
               MYSQL_YYABORT;
diff --git a/sql/unireg.cc b/sql/unireg.cc
index 525e7a8a56a..ae860f0143b 100644
--- a/sql/unireg.cc
+++ b/sql/unireg.cc
@@ -86,6 +86,13 @@ static uchar* extra2_write_str(uchar *pos, const LEX_CSTRING &str)
   return pos + str.length;
 }
 
+static uchar* extra2_write_str(uchar *pos, Binary_string *str)
+{
+  pos= extra2_write_len(pos, str->length());
+  memcpy(pos, str->ptr(), str->length());
+  return pos + str->length();
+}
+
 static uchar *extra2_write(uchar *pos, enum extra2_frm_value_type type,
                            const LEX_CSTRING &str)
 {
@@ -178,11 +185,11 @@ class Field_data_type_info_image: public BinaryStringBuffer<512>
   {
     return net_store_length(pos, length);
   }
-  static uchar *store_string(uchar *pos, const LEX_CSTRING &str)
+  static uchar *store_string(uchar *pos, Binary_string *str)
   {
-    pos= store_length(pos, str.length);
-    memcpy(pos, str.str, str.length);
-    return pos + str.length;
+    pos= store_length(pos, str->length());
+    memcpy(pos, str->ptr(), str->length());
+    return pos + str->length();
   }
   static uint store_length_required_length(ulonglong length)
   {
@@ -206,7 +213,7 @@ public:
       return true; // Error
     uchar *pos= (uchar *) end();
     pos= store_length(pos, fieldnr);
-    pos= store_string(pos, type_info.lex_cstring());
+    pos= store_string(pos, &type_info);
     size_t new_length= (const char *) pos - ptr();
     DBUG_ASSERT(new_length < alloced_length());
     length((uint32) new_length);
@@ -471,7 +478,7 @@ LEX_CUSTRING build_frm_image(THD *thd, const LEX_CSTRING &table,
       goto err;
     }
     *pos= EXTRA2_FIELD_DATA_TYPE_INFO;
-    pos= extra2_write_str(pos + 1, field_data_type_info_image.lex_cstring());
+    pos= extra2_write_str(pos + 1, &field_data_type_info_image);
   }
 
   // PERIOD
diff --git a/sql/wsrep_mysqld.cc b/sql/wsrep_mysqld.cc
index 0c31631d19b..9a2d5e635a5 100644
--- a/sql/wsrep_mysqld.cc
+++ b/sql/wsrep_mysqld.cc
@@ -1968,7 +1968,7 @@ static int wsrep_create_sp(THD *thd, uchar** buf, size_t* buf_len)
   if (sp->m_handler->type() == SP_TYPE_FUNCTION)
   {
     sp_returns_type(thd, retstr, sp);
-    returns= retstr.lex_cstring();
+    retstr.get_value(&returns);
   }
   if (sp->m_handler->
       show_create_sp(thd, &log_query,
diff --git a/sql/wsrep_schema.cc b/sql/wsrep_schema.cc
index 80bc53b1790..7a3519d51f3 100644
--- a/sql/wsrep_schema.cc
+++ b/sql/wsrep_schema.cc
@@ -492,12 +492,11 @@ static int scan(TABLE* table, uint field, INTTYPE& val)
 
 static int scan(TABLE* table, uint field, char* strbuf, uint strbuf_len)
 {
-  String str;
-  (void)table->field[field]->val_str(&str);
-  LEX_CSTRING tmp= str.lex_cstring();
-  uint len = tmp.length;
-  strncpy(strbuf, tmp.str, std::min(len, strbuf_len));
-  strbuf[strbuf_len - 1]= '\0';
+  uint len;
+  StringBuffer<STRING_BUFFER_USUAL_SIZE> str;
+  (void) table->field[field]->val_str(&str);
+  len= str.length();
+  strmake(strbuf, str.ptr(), MY_MIN(len, strbuf_len-1));
   return 0;
 }
 
diff --git a/storage/spider/spd_malloc.cc b/storage/spider/spd_malloc.cc
index 9f4203ae33d..a9438f2ac58 100644
--- a/storage/spider/spd_malloc.cc
+++ b/storage/spider/spd_malloc.cc
@@ -476,9 +476,10 @@ char *spider_string::c_ptr_safe()
 
 LEX_STRING spider_string::lex_string() const
 {
+  LEX_STRING res= { (char*) str.ptr(), str.length() };
   DBUG_ENTER("spider_string::lex_string");
   DBUG_PRINT("info",("spider this=%p", this));
-  DBUG_RETURN(str.lex_string());
+  DBUG_RETURN(res);
 }
 
 void spider_string::set(