MDEV-5816: Stored programs: validation of stored program statementsbb-10.11-MDEV-5816

This is the prerequisite patch introducing the class sp_lex_instr
that encapsulates access to an instance of the class sp_lex_keeper.
Every SP instruction that need to get access to a LEX object on its
processing should inherit this class and implement two abstract methods:
  is_invalid(),
  invalidate().

These methods will be used in subsequent patches to implement recompilation of
SP instructions on failure.

Currently, the following instructions are derived from the class sp_lex_instr:
  sp_instr_stmt,
  sp_instr_set,
  sp_instr_set_trigger_field,
  sp_instr_jump_if_not,
  sp_instr_freturn,
  sp_instr_cpush,
  sp_instr_cursor_copy_struct,
  sp_instr_set_case_expr

Additionally, this patch converts the class sp_instr_opt_meta
to base abstract class (that is, not inherited from the class
sp_instr). Since this class originally was designed to provide a way
for opimizer to update a destination address for jump SP-instructions,
the only useful method at the interface of this class is set_destination
and therefore inheritance from the class sp_instr is meaningless.

Every jump SP instruction now must be inhereted directly from
the class sp_instr_opt_meta and additionally from either the class
sp_lex_instr or sp_instr depending on whether this SP instruction
need to get access to a LEX object or not.

Moreover, the class sp_cursor doesn't own a data member of
the class sp_lex_keeper any more. Instead, the virtual method
get_lex_keeper() has been added to the class sp_cursor() that
returns nullptr and this method is overridden in the derived class
sp_instr_cpush to provide a pointer to a real instance of
the class sp_lex_keeper. Doing this way we exclude duplication
of a data member of the type sp_lex_keeper at the class sp_instr_cpush
since it is derived both from sp_lex_instr and sp_cursor, and sp_lex_instr
already encapsulates a data member of the class sp_lex_keeper.

1 files changed, 3 insertions, 7 deletions

diff --git a/sql/sql_class.h b/sql/sql_class.h
index 8fc1b5839a2..c0f0480faa5 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -5942,19 +5942,17 @@ private:
 public:
   sp_cursor()
    :result(NULL, false),
-    m_lex_keeper(NULL),
     server_side_cursor(NULL)
   { }
-  sp_cursor(THD *thd_arg, sp_lex_keeper *lex_keeper, bool view_structure_only)
+  sp_cursor(THD *thd_arg, bool view_structure_only)
    :result(thd_arg, view_structure_only),
-    m_lex_keeper(lex_keeper),
     server_side_cursor(NULL)
   {}
 
   virtual ~sp_cursor()
   { destroy(); }
 
-  sp_lex_keeper *get_lex_keeper() { return m_lex_keeper; }
+  virtual sp_lex_keeper *get_lex_keeper() { return nullptr; }
 
   int open(THD *thd);
 
@@ -5967,17 +5965,15 @@ public:
 
   bool export_structure(THD *thd, Row_definition_list *list);
 
-  void reset(THD *thd_arg, sp_lex_keeper *lex_keeper)
+  void reset(THD *thd_arg)
   {
     sp_cursor_statistics::reset();
     result.reset(thd_arg);
-    m_lex_keeper= lex_keeper;
     server_side_cursor= NULL;
   }
 
 private:
   Select_fetch_into_spvars result;
-  sp_lex_keeper *m_lex_keeper;
   Server_side_cursor *server_side_cursor;
   void destroy();
 };