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, 8 deletions

diff --git a/sql/partition_element.h b/sql/partition_element.h
index b979b7a58e6..c774994b7f5 100644
--- a/sql/partition_element.h
+++ b/sql/partition_element.h
@@ -96,14 +96,14 @@ public:
   ha_rows part_max_rows;
   ha_rows part_min_rows;
   longlong range_value;
-  char *partition_name;
-  char *tablespace_name;
+  const char *partition_name;
+  const char *tablespace_name;
   struct st_ddl_log_memory_entry *log_entry;
-  char* part_comment;
-  char* data_file_name;
-  char* index_file_name;
+  const char* part_comment;
+  const char* data_file_name;
+  const char* index_file_name;
   handlerton *engine_type;
-  LEX_STRING connect_string;
+  LEX_CSTRING connect_string;
   enum partition_state part_state;
   uint16 nodegroup_id;
   bool has_null_value;
@@ -115,7 +115,7 @@ public:
     partition_name(NULL), tablespace_name(NULL),
     log_entry(NULL), part_comment(NULL),
     data_file_name(NULL), index_file_name(NULL),
-    engine_type(NULL), connect_string(null_lex_str), part_state(PART_NORMAL),
+    engine_type(NULL), connect_string(null_clex_str), part_state(PART_NORMAL),
     nodegroup_id(UNDEF_NODEGROUP), has_null_value(FALSE),
     signed_flag(FALSE), max_value(FALSE)
   {
@@ -129,7 +129,7 @@ public:
     data_file_name(part_elem->data_file_name),
     index_file_name(part_elem->index_file_name),
     engine_type(part_elem->engine_type),
-    connect_string(null_lex_str),
+    connect_string(null_clex_str),
     part_state(part_elem->part_state),
     nodegroup_id(part_elem->nodegroup_id),
     has_null_value(FALSE)