A fix and a test case for Bug#6513 "Test Suite: Values inserted by using

cursor is interpreted latin1 character and Bug#9819 "Cursors: Mysql Server
Crash while fetching from table with 5 million records."
A fix for a possible memory leak when fetching into an SP cursor
in a long loop.
The patch uses a common implementation of cursors in the binary protocol and 
in stored procedures and implements materialized cursors.
For implementation details, see comments in sql_cursor.cc


include/my_sys.h:
  - declaration for multi_alloc_root
libmysqld/Makefile.am:
  - drop protocol_cursor.cc, add sql_cursor.cc (replaces the old
  implementation of cursors with a new one)
mysql-test/r/ctype_ujis.result:
  - test results fixed (a test case for Bug#6513)
mysql-test/r/sp-big.result:
  - test results fixed (a test case for Bug#9819)
mysql-test/t/ctype_ujis.test:
  Add a test case for Bug#6513 "Test Suite: Values inserted by using cursor is
   interpreted latin1 character"
mysql-test/t/sp-big.test:
  Add a restricted test case for Bug#9819 "Cursors: Mysql Server Crash
  while fetching from table with 5 million records."
mysys/my_alloc.c:
  - an implementation of multi_alloc_root; this is largely a copy-paste
    from mulalloc.c, but the function is small and there is no easy way
    to reuse the existing C function.
sql/Makefile.am:
  - add sql_cursor.h, sql_cursor.cc (a new implementation of stored procedure
  cursors) and drop protocol_cursor.cc (the old one)
sql/handler.cc:
  - now TABLE object has its mem_root always initialized.
    Adjust the implementation handler::ha_open
sql/item_subselect.cc:
  - adjust to the changed declaration of st_select_lex_unit::prepare
sql/protocol.h:
  - drop Protocol_cursor
sql/sp_head.cc:
  - move juggling with Query_arena::free_list and Item::next to
    sp_eval_func_item, as this is needed in 3 places already.
sql/sp_head.h:
  - declare a no-op implementation for cleanup_stmt in sp_instr_cpush.
    This method is needed for non-materializing cursors, which are yet not 
    used in stored procedures.
  - declaration for sp_eval_func_item
sql/sp_rcontext.cc:
  - reimplement sp_cursor using the new implementation of server side cursors.
  - use sp_eval_func_item to assign values of SP variables from the
    row fetched from a cursor. This should fix a possible memory leak in 
    the old implementation of sp_cursor::fetch
sql/sp_rcontext.h:
  - reimplement sp_cursor using the new implementation of server side cursors.
sql/sql_class.cc:
  - disable the functionality that closes transient cursors at commit/rollback;
    transient cursors are not used in 5.0, instead we use materialized ones.
    To be enabled in a later version.
sql/sql_class.h:
  - adjust to the rename Cursor -> Server_side_cursor
  - additional declarations of select_union used in materialized cursors
sql/sql_derived.cc:
  - reuse bits of tmp table code in UNION, derived tables, and materialized
    cursors
  - cleanup comments
sql/sql_lex.h:
  - declarations of auxiliary methods used by materialized cursors
  - a cleanup in st_select_lex_unit interface
sql/sql_list.h:
  - add an array operator new[] to class Sql_alloc
sql/sql_prepare.cc:
  - split the tight coupling of cursors and prepared statements to reuse 
    the same implementation in stored procedures
  - cleanups of error processing in Prepared_statement::{prepare,execute}
sql/sql_select.cc:
  - move the implementation of sensitive (non-materializing) cursors to 
    sql_cursor.cc
  - make temporary tables self-contained: the table, its record and fields
    are allocated in TABLE::mem_root. This implementation is not clean
    and resets thd->mem_root several times because of the way create_tmp_table 
    works (many additional things are done inside it).
  - adjust to the changed declaration of st_select_lex_unit::prepare
sql/sql_select.h:
  - move the declaration of sensitive (non-materializing) cursors to 
    sql_cursor.cc
sql/sql_union.cc:
  - move pieces of st_select_unit::prepare to select_union and st_table
    methods to be able to reuse code in the implementation of materialized
    cursors
sql/sql_view.cc:
  - adjust to the changed signature of st_select_lex_unit::prepare
sql/table.cc:
  - implement auxiliary st_table methods for use with temporary tables
sql/table.h:
  - add declarations for auxiliary methods of st_table used to work with 
   temporary tables
tests/mysql_client_test.c:
  - if cursors are materialized, a parallel update of the table used
    in the cursor may go through: update the test.
sql/sql_cursor.cc:
  New BitKeeper file ``sql/sql_cursor.cc'' -- implementation of server side
  cursors
sql/sql_cursor.h:
  New BitKeeper file ``sql/sql_cursor.h'' - declarations for
  server side cursors.

sql/table.cc

@@ -1687,6 +1687,63 @@ db_type get_table_type(THD *thd, const char *name)
   DBUG_RETURN(ha_checktype(thd,(enum db_type) (uint) *(head+3),0,0));
 }
 
+/*
+  Create Item_field for each column in the table.
+
+  SYNPOSIS
+    st_table::fill_item_list()
+      item_list          a pointer to an empty list used to store items
+
+  DESCRIPTION
+    Create Item_field object for each column in the table and
+    initialize it with the corresponding Field. New items are
+    created in the current THD memory root.
+
+  RETURN VALUE
+    0                    success
+    1                    out of memory
+*/
+
+bool st_table::fill_item_list(List<Item> *item_list) const
+{
+  /*
+    All Item_field's created using a direct pointer to a field
+    are fixed in Item_field constructor.
+  */
+  for (Field **ptr= field; *ptr; ptr++)
+  {
+    Item_field *item= new Item_field(*ptr);
+    if (!item || item_list->push_back(item))
+      return TRUE;
+  }
+  return FALSE;
+}
+
+/*
+  Reset an existing list of Item_field items to point to the
+  Fields of this table.
+
+  SYNPOSIS
+    st_table::fill_item_list()
+      item_list          a non-empty list with Item_fields
+
+  DESCRIPTION
+    This is a counterpart of fill_item_list used to redirect
+    Item_fields to the fields of a newly created table.
+    The caller must ensure that number of items in the item_list
+    is the same as the number of columns in the table.
+*/
+
+void st_table::reset_item_list(List<Item> *item_list) const
+{
+  List_iterator_fast<Item> it(*item_list);
+  for (Field **ptr= field; *ptr; ptr++)
+  {
+    Item_field *item_field= (Item_field*) it++;
+    DBUG_ASSERT(item_field != 0);
+    item_field->reset_field(*ptr);
+  }
+}
 
 /*
   calculate md5 of query