MDEV-11245 Move prepare_create_field and sp_prepare_create_field() as methods to Column_definition

Some upcoming tasks, e.g.:
- MDEV-10577 sql_mode=ORACLE: %TYPE in variable declarations
- MDEV-10914 ROW data type for stored routine variables

will need to reuse the code implemented in prepare_create_field(),
sp_prepare_create_field(), prepare_blob_field().

Before reusing this code, it's a good idea to move these global functions
as methods to Column_definition.

This patch:
- actually moves prepare_create_field(), sp_prepare_create_field(),
  prepare_blob_field() as methods to Column_definition
- makes sp_prepare_create_field() call prepare_create_field() at the end,
  to avoid duplicate code in MDEV-10577 and MDEV-10914.
- changes the return data type for prepare_create_field() from int to bool,
  to make it consistent with all other functions returning "ok" or "error".
- moves the implementation sp_head::fill_field_definition() from sp_head.cc
  to sp_head.h, as it now uses globally visible Column_definition methods,
  and is very simple, so inlining is now possible.
- removes the unused "LEX*" argument from sp_head::fill_field_definition()

1 files changed, 1 insertions, 1 deletions

diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index 7c06ff96c32..728416c8df6 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -2874,7 +2874,7 @@ bool Column_definition::prepare_create_field(uint *blob_columns,
     if (!(table_flags & HA_CAN_GEOMETRY))
     {
       my_error(ER_CHECK_NOT_IMPLEMENTED, MYF(0), "GEOMETRY");
-      DBUG_RETURN(1);
+      DBUG_RETURN(true);
     }
     pack_flag= FIELDFLAG_GEOM |
       pack_length_to_packflag(pack_length - portable_sizeof_char_ptr);