Simplistic, experimental framework for Stored Procedures (SPs).

Implements creation and dropping of PROCEDUREs, IN, OUT, and INOUT parameters,
single-statement procedures, rudimentary multi-statement (begin-end) prodedures
(when the client can handle it), and local variables.
Missing most of the embedded SQL language, all attributes, FUNCTIONs, error handling,
reparses procedures at each call (no caching), etc, etc.
Certainly buggy too, but procedures can actually be created and called....


sql/Makefile.am:
  Added SP files.
sql/item.cc:
  Added this*_item() methods for Item_splocal. (SP local variable)
sql/item.h:
  Added this*_item() methods for SPs in Item, and the new Item_splocal
  class (SP local variable).
sql/lex.h:
  Added new symbols for SPs. (Note: SPSET is temporary and will go away later.)
sql/sql_class.cc:
  Initialize SP runtime context in THD.
sql/sql_class.h:
  Add SP runtime context to THD.
sql/sql_lex.cc:
  Init. buf pointer to beginning of command (needed by SPs).
  Also initialize SP head and parse time context.
sql/sql_lex.h:
  New SQLCOM_ tags for SPs, and added pointer to beginning of command pointer and
  SP head and parse-time context to LEX.
sql/sql_parse.cc:
  Added SQLCOM_CREATE_PROCEDURE, _CALL, _ALTER_PROCEDURE and _DROP_PROCEDURE cases.
  (Still rudimentary and lacking proper error handling...)
sql/sql_yacc.yy:
  Lots and lots of additions for SPs...
  (Still even more missing, and no error messages...)

sql/sp_pcontext.cc

@@ -0,0 +1,91 @@
+/* Copyright (C) 2002 MySQL AB
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
+
+#ifdef __GNUC__
+#pragma implementation
+#endif
+
+#if defined(WIN32) || defined(__WIN__)
+#undef SAFEMALLOC				/* Problems with threads */
+#endif
+
+#include "mysql_priv.h"
+#include "sp_pcontext.h"
+
+sp_pcontext::sp_pcontext()
+    : m_params(0), m_framesize(0), m_i(0)
+{
+  m_pvar_size = 16;
+  m_pvar = (sp_pvar_t *)my_malloc(m_pvar_size * sizeof(sp_pvar_t), MYF(MY_WME));
+  if (m_pvar)
+    memset(m_pvar, 0, m_pvar_size * sizeof(sp_pvar_t));
+}
+
+void
+sp_pcontext::grow()
+{
+  uint sz = m_pvar_size + 8;
+  sp_pvar_t *a = (sp_pvar_t *)my_realloc((char *)m_pvar,
+					 sz * sizeof(sp_pvar_t),
+					 MYF(MY_WME | MY_ALLOW_ZERO_PTR));
+
+  if (a)
+  {
+    m_pvar_size = sz;
+    m_pvar = a;
+  }
+}
+
+/* This does a linear search (from newer to older variables, in case
+** we have shadowed names).
+** It's possible to have a more efficient allocation and search method,
+** but it might not be worth it. The typical number of parameters and
+** variables will in most cases be low (a handfull).
+** And this is only called during parsing.
+*/
+sp_pvar_t *
+sp_pcontext::find_pvar(LEX_STRING *name)
+{
+  String n(name->str, name->length, default_charset_info);
+  uint i = m_i;
+
+  while (i-- > 0)
+  {
+    if (stringcmp(&n, m_pvar[i].name->const_string()) == 0)
+      return m_pvar + i;
+  }
+  return NULL;
+}
+
+void
+sp_pcontext::push(LEX_STRING *name, enum enum_field_types type,
+		  sp_param_mode_t mode)
+{
+  if (m_i >= m_pvar_size)
+    grow();
+  if (m_i < m_pvar_size)
+  {
+    if (m_i == m_framesize)
+      m_framesize += 1;
+    m_pvar[m_i].name= new Item_string(name->str, name->length,
+				      default_charset_info);
+    m_pvar[m_i].type= type;
+    m_pvar[m_i].mode= mode;
+    m_pvar[m_i].offset= m_i;
+    m_pvar[m_i].isset= (mode == sp_param_out ? FALSE : TRUE);
+    m_i += 1;
+  }
+}