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, 6 insertions, 5 deletions

diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index c497a41673e..915387d6ba9 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -297,6 +297,7 @@ static TYPELIB tc_heuristic_recover_typelib=
 
 const char *first_keyword= "first", *binary_keyword= "BINARY";
 const char *my_localhost= "localhost", *delayed_user= "DELAYED";
+const char *quoted_string= "%`s";
 
 bool opt_large_files= sizeof(my_off_t) > 4;
 static my_bool opt_autocommit; ///< for --autocommit command-line option
@@ -629,10 +630,10 @@ my_bool encrypt_binlog;
 my_bool encrypt_tmp_disk_tables, encrypt_tmp_files;
 
 /** name of reference on left expression in rewritten IN subquery */
-const char *in_left_expr_name= "<left expr>";
+const LEX_CSTRING in_left_expr_name= {STRING_WITH_LEN("<left expr>") };
 /** name of additional condition */
-const char *in_additional_cond= "<IN COND>";
-const char *in_having_cond= "<IN HAVING>";
+const LEX_CSTRING in_having_cond= {STRING_WITH_LEN("<IN HAVING>") };
+const LEX_CSTRING in_additional_cond= {STRING_WITH_LEN("<IN COND>") };
 
 /** Number of connection errors when selecting on the listening port */
 ulong connection_errors_select= 0;
@@ -4884,7 +4885,7 @@ static int init_default_storage_engine_impl(const char *opt_name,
     return 0;
   }
 
-  LEX_STRING name= { engine_name, strlen(engine_name) };
+  LEX_CSTRING name= { engine_name, strlen(engine_name) };
   plugin_ref plugin;
   handlerton *hton;
   if ((plugin= ha_resolve_by_name(0, &name, false)))
@@ -5323,7 +5324,7 @@ static int init_server_components()
   else
   {
     /* fall back to the log files if tables are not present */
-    LEX_STRING csv_name={C_STRING_WITH_LEN("csv")};
+    LEX_CSTRING csv_name={STRING_WITH_LEN("csv")};
     if (!plugin_is_ready(&csv_name, MYSQL_STORAGE_ENGINE_PLUGIN))
     {
       /* purecov: begin inspected */