Changing field::field_name and Item::name to LEX_CSTRING

Benefits of this patch:
- Removed a lot of calls to strlen(), especially for field_string
- Strings generated by parser are now const strings, less chance of
  accidently changing a string
- Removed a lot of calls with LEX_STRING as parameter (changed to pointer)
- More uniform code
- Item::name_length was not kept up to date. Now fixed
- Several bugs found and fixed (Access to null pointers,
  access of freed memory, wrong arguments to printf like functions)
- Removed a lot of casts from (const char*) to (char*)

Changes:
- This caused some ABI changes
  - lex_string_set now uses LEX_CSTRING
  - Some fucntions are now taking const char* instead of char*
- Create_field::change and after changed to LEX_CSTRING
- handler::connect_string, comment and engine_name() changed to LEX_CSTRING
- Checked printf() related calls to find bugs. Found and fixed several
  errors in old code.
- A lot of changes from LEX_STRING to LEX_CSTRING, especially related to
  parsing and events.
- Some changes from LEX_STRING and LEX_STRING & to LEX_CSTRING*
- Some changes for char* to const char*
- Added printf argument checking for my_snprintf()
- Introduced null_clex_str, star_clex_string, temp_lex_str to simplify
  code
- Added item_empty_name and item_used_name to be able to distingush between
  items that was given an empty name and items that was not given a name
  This is used in sql_yacc.yy to know when to give an item a name.
- select table_name."*' is not anymore same as table_name.*
- removed not used function Item::rename()
- Added comparision of item->name_length before some calls to
  my_strcasecmp() to speed up comparison
- Moved Item_sp_variable::make_field() from item.h to item.cc
- Some minimal code changes to avoid copying to const char *
- Fixed wrong error message in wsrep_mysql_parse()
- Fixed wrong code in find_field_in_natural_join() where real_item() was
  set when it shouldn't
- ER_ERROR_ON_RENAME was used with extra arguments.
- Removed some (wrong) ER_OUTOFMEMORY, as alloc_root will already
  give the error.

TODO:
- Check possible unsafe casts in plugin/auth_examples/qa_auth_interface.c
- Change code to not modify LEX_CSTRING for database name
  (as part of lower_case_table_names)

1 files changed, 8 insertions, 7 deletions

diff --git a/sql/parse_file.cc b/sql/parse_file.cc
index 1cd294c1c7a..b091259d273 100644
--- a/sql/parse_file.cc
+++ b/sql/parse_file.cc
@@ -136,7 +136,7 @@ static ulonglong view_algo_from_frm(ulonglong val)
 
 
 static my_bool
-write_parameter(IO_CACHE *file, uchar* base, File_option *parameter)
+write_parameter(IO_CACHE *file, const uchar* base, File_option *parameter)
 {
   char num_buf[20];			// buffer for numeric operations
   // string for numeric operations
@@ -248,8 +248,9 @@ write_parameter(IO_CACHE *file, uchar* base, File_option *parameter)
 
 
 my_bool
-sql_create_definition_file(const LEX_STRING *dir, const LEX_STRING *file_name,
-			   const LEX_STRING *type,
+sql_create_definition_file(const LEX_CSTRING *dir,
+                           const LEX_CSTRING *file_name,
+			   const LEX_CSTRING *type,
 			   uchar* base, File_option *parameters)
 {
   File handler;
@@ -399,7 +400,7 @@ my_bool rename_in_schema_file(THD *thd,
 */
 
 File_parser * 
-sql_parse_prepare(const LEX_STRING *file_name, MEM_ROOT *mem_root,
+sql_parse_prepare(const LEX_CSTRING *file_name, MEM_ROOT *mem_root,
 		  bool bad_format_errors)
 {
   MY_STAT stat_info;
@@ -598,13 +599,13 @@ read_escaped_string(const char *ptr, const char *eol, LEX_STRING *str)
 
 const char *
 parse_escaped_string(const char *ptr, const char *end, MEM_ROOT *mem_root,
-                     LEX_STRING *str)
+                     LEX_CSTRING *str)
 {
   const char *eol= strchr(ptr, '\n');
 
   if (eol == 0 || eol >= end ||
       !(str->str= (char*) alloc_root(mem_root, (eol - ptr) + 1)) ||
-      read_escaped_string(ptr, eol, str))
+      read_escaped_string(ptr, eol, (LEX_STRING*) str))
     return 0;
     
   return eol+1;
@@ -802,7 +803,7 @@ File_parser::parse(uchar* base, MEM_ROOT *mem_root,
 	case FILE_OPTIONS_ESTRING:
 	{
 	  if (!(ptr= parse_escaped_string(ptr, end, mem_root,
-					  (LEX_STRING *)
+					  (LEX_CSTRING *)
 					  (base + parameter->offset))))
 	  {
 	    my_error(ER_FPARSER_ERROR_IN_PARAMETER, MYF(0),