MDEV-21689 Add Sql_cmd for GRANT/REVOKE statements

Rewriting GRANT/REVOKE grammar to use more bison stack and use Sql_cmd_ style

1. Removing a few members from LEX:
   - uint grant, grant_to_col, which_columns
   - List<LEX_COLUMN> columns
   - bool all_privileges
2. Adding classes Grand_object_name, Lex_grant_object_name
3. Adding classes Grand_privilege, Lex_grand_privilege
4. Adding struct Lex_column_list_privilege_st, class Lex_column_list_privilege
5. Rewriting the GRANT/REVOKE grammar to use new classes and pass them through
   bison stack (rather than directly access LEX members)
6. Adding classes Sql_cmd_grant* and Sql_cmd_revoke*,
   changing GRANT/REVOKE to use LEX::m_sql_cmd.
7. Adding the "sp_handler" grammar rule and removing some duplicate grammar
   for GRANT/REVOKE for different kinds of SP objects.
8. Adding a new rule comma_separated_ident_list, reusing it in:
   - with_column_list
   - colum_list_privilege

sql/grant.cc

@@ -0,0 +1,108 @@
+/*
+   Copyright (c) 2009, 2020, MariaDB Corporation
+
+   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; version 2 of the License.
+
+   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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335  USA */
+
+#include "mariadb.h"
+#include "sql_acl.h"
+
+
+bool Grant_privilege::add_column_privilege(THD *thd,
+                                           const Lex_ident_sys &name,
+                                           uint which_grant)
+{
+  String *new_str= new (thd->mem_root) String((const char*) name.str,
+                                              name.length,
+                                              system_charset_info);
+  if (unlikely(new_str == NULL))
+    return true;
+  List_iterator <LEX_COLUMN> iter(m_columns);
+  class LEX_COLUMN *point;
+  while ((point=iter++))
+  {
+    if (!my_strcasecmp(system_charset_info,
+                       point->column.c_ptr(), new_str->c_ptr()))
+      break;
+  }
+  m_column_privilege_total|= which_grant;
+  if (point)
+  {
+    point->rights |= which_grant;
+    return false;
+  }
+
+  LEX_COLUMN *col= new (thd->mem_root) LEX_COLUMN(*new_str, which_grant);
+  if (unlikely(col == NULL))
+    return true;
+  return m_columns.push_back(col, thd->mem_root);
+}
+
+
+bool Grant_privilege::add_column_list_privilege(THD *thd,
+                                                List<Lex_ident_sys> &list,
+                                                uint privilege)
+{
+  Lex_ident_sys *col;
+  List_iterator<Lex_ident_sys> it(list);
+  while ((col= it++))
+  {
+    if (add_column_privilege(thd, *col, privilege))
+      return true;
+  }
+  return false;
+}
+
+
+uint Grant_object_name::all_privileges_by_type() const
+{
+  switch (m_type) {
+  case STAR:        return DB_ACLS & ~GRANT_ACL;
+  case IDENT_STAR:  return DB_ACLS & ~GRANT_ACL;
+  case STAR_STAR:   return GLOBAL_ACLS & ~GRANT_ACL;
+  case TABLE_IDENT: return TABLE_ACLS & ~GRANT_ACL;
+  }
+  return 0;
+}
+
+
+bool Grant_privilege::set_object_name(THD *thd,
+                                      const Grant_object_name &ident,
+                                      SELECT_LEX *sel,
+                                      uint with_grant_option)
+{
+  DBUG_ASSERT(!m_all_privileges || !m_columns.elements);
+
+  m_db= ident.m_db;
+  if (m_all_privileges)
+    m_object_privilege= ident.all_privileges_by_type();
+  m_object_privilege|= with_grant_option;
+  switch (ident.m_type)
+  {
+  case Lex_grant_object_name::STAR:
+  case Lex_grant_object_name::IDENT_STAR:
+  case Lex_grant_object_name::STAR_STAR:
+    if (!m_all_privileges && m_columns.elements)
+    {
+      // e.g. GRANT SELECT (a) ON db.*
+      my_error(ER_ILLEGAL_GRANT_FOR_TABLE, MYF(0));
+      return true;
+    }
+    return false;
+  case Lex_grant_object_name::TABLE_IDENT:
+    m_db= ident.m_table_ident->db;
+    return !sel->add_table_to_list(thd, ident.m_table_ident,
+                                   NULL, TL_OPTION_UPDATING);
+  }
+  return false; // Make gcc happy
+}