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, 5 deletions

diff --git a/sql/item_create.h b/sql/item_create.h
index 05fe48f656a..a2d985dd3e8 100644
--- a/sql/item_create.h
+++ b/sql/item_create.h
@@ -56,7 +56,7 @@ public:
     @param item_list The list of arguments to the function, can be NULL
     @return An item representing the parsed function call, or NULL
   */
-  virtual Item *create_func(THD *thd, LEX_STRING name, List<Item> *item_list) = 0;
+  virtual Item *create_func(THD *thd, LEX_CSTRING *name, List<Item> *item_list) = 0;
 
 protected:
   /** Constructor */
@@ -83,7 +83,8 @@ public:
     @param item_list The list of arguments to the function, can be NULL
     @return An item representing the parsed function call
   */
-  virtual Item *create_func(THD *thd, LEX_STRING name, List<Item> *item_list);
+  virtual Item *create_func(THD *thd, LEX_CSTRING *name,
+                            List<Item> *item_list);
 
   /**
     The builder create method, for qualified functions.
@@ -94,7 +95,7 @@ public:
     @param item_list The list of arguments to the function, can be NULL
     @return An item representing the parsed function call
   */
-  virtual Item *create_with_db(THD *thd, LEX_STRING db, LEX_STRING name,
+  virtual Item *create_with_db(THD *thd, LEX_CSTRING *db, LEX_CSTRING *name,
                                bool use_explicit_name,
                                List<Item> *item_list) = 0;
 
@@ -112,7 +113,8 @@ protected:
   @param name The native function name
   @return The native function builder associated with the name, or NULL
 */
-extern Create_func * find_native_function_builder(THD *thd, LEX_STRING name);
+extern Create_func *find_native_function_builder(THD *thd,
+                                                 const LEX_CSTRING *name);
 
 
 /**
@@ -131,7 +133,8 @@ extern Create_qfunc * find_qualified_function_builder(THD *thd);
 class Create_udf_func : public Create_func
 {
 public:
-  virtual Item *create_func(THD *thd, LEX_STRING name, List<Item> *item_list);
+  virtual Item *create_func(THD *thd, LEX_CSTRING *name,
+                            List<Item> *item_list);
 
   /**
     The builder create method, for User Defined Functions.