MDEV-5816: Stored programs: validation of stored program statements

This is the prerequisite patch to move the data member
LEX::trg_table_fields to the class sp_head and rename it as
m_trg_table_fields.

This data member is used for handling OLD/NEW pseudo-rows inside
a trigger body and in order to be able to re-parse a trigger body
the data member must be moved from the struct LEX to the class sp_head.

sql/sp_head.cc

@@ -801,12 +801,6 @@ sp_head::init(LEX *lex)
   if (!lex->spcont)
     DBUG_VOID_RETURN;
 
-  /*
-    Altough trg_table_fields list is used only in triggers we init for all
-    types of stored procedures to simplify reset_lex()/restore_lex() code.
-  */
-  lex->trg_table_fields.empty();
-
   DBUG_VOID_RETURN;
 }
 
@@ -2492,8 +2486,6 @@ sp_head::merge_lex(THD *thd, LEX *oldlex, LEX *sublex)
 
   sublex->set_trg_event_type_for_tables();
 
-  oldlex->trg_table_fields.push_back(&sublex->trg_table_fields);
-
   /* If this substatement is unsafe, the entire routine is too. */
   DBUG_PRINT("info", ("sublex->get_stmt_unsafe_flags: 0x%x",
                       sublex->get_stmt_unsafe_flags()));

sql/sp_head.h

@@ -952,6 +952,15 @@ protected:
   push_backpatch(THD *thd, sp_instr *, sp_label *, List<bp_t> *list,
                  backpatch_instr_type itype);
 
+public:
+  /*
+    List of all items (Item_trigger_field objects) representing fields in
+    old/new version of row in trigger. We use this list for checking whenever
+    all such fields are valid at trigger creation time and for binding these
+    fields to TABLE object at table open (altough for latter pointer to table
+    being opened is probably enough).
+  */
+  SQL_I_List<Item_trigger_field> m_trg_table_fields;
 }; // class sp_head : public Sql_alloc
 
 

sql/sql_lex.cc

@@ -239,7 +239,7 @@ bool LEX::set_trigger_new_row(const LEX_CSTRING *name, Item *val)
     Let us add this item to list of all Item_trigger_field
     objects in trigger.
   */
-  trg_table_fields.link_in_list(trg_fld, &trg_fld->next_trg_field);
+  sphead->m_trg_table_fields.link_in_list(trg_fld, &trg_fld->next_trg_field);
 
   return sphead->add_instr(sp_fld);
 }
@@ -7883,7 +7883,7 @@ Item *LEX::create_and_link_Item_trigger_field(THD *thd,
     in trigger.
   */
   if (likely(trg_fld))
-    trg_table_fields.link_in_list(trg_fld, &trg_fld->next_trg_field);
+    sphead->m_trg_table_fields.link_in_list(trg_fld, &trg_fld->next_trg_field);
 
   return trg_fld;
 }

sql/sql_lex.h

@@ -3536,14 +3536,6 @@ public:
 
   /* Characterstics of trigger being created */
   st_trg_chistics trg_chistics;
-  /*
-    List of all items (Item_trigger_field objects) representing fields in
-    old/new version of row in trigger. We use this list for checking whenever
-    all such fields are valid at trigger creation time and for binding these
-    fields to TABLE object at table open (altough for latter pointer to table
-    being opened is probably enough).
-  */
-  SQL_I_List<Item_trigger_field> trg_table_fields;
 
   /*
     stmt_definition_begin is intended to point to the next word after
@@ -5102,7 +5094,6 @@ public:
     spcont= oldlex->spcont;
     /* Keep the parent trigger stuff too */
     trg_chistics= oldlex->trg_chistics;
-    trg_table_fields.empty();
     sp_lex_in_use= false;
   }
 };

sql/sql_trigger.cc

@@ -939,7 +939,7 @@ bool Table_triggers_list::create_trigger(THD *thd, TABLE_LIST *tables,
   */
   old_field= new_field= table->field;
 
-  for (trg_field= lex->trg_table_fields.first;
+  for (trg_field= lex->sphead->m_trg_table_fields.first;
        trg_field; trg_field= trg_field->next_trg_field)
   {
     /*
@@ -1797,7 +1797,7 @@ bool Table_triggers_list::check_n_load(THD *thd, const LEX_CSTRING *db,
           in old/new versions of row in trigger into lists containing all such
           objects for the trigger_list with same action and timing.
         */
-        trigger->trigger_fields= lex.trg_table_fields.first;
+        trigger->trigger_fields= sp->m_trg_table_fields.first;
         /*
           Also let us bind these objects to Field objects in table being
           opened.
@@ -1807,7 +1807,7 @@ bool Table_triggers_list::check_n_load(THD *thd, const LEX_CSTRING *db,
           SELECT)...
           Anyway some things can be checked only during trigger execution.
         */
-        for (Item_trigger_field *trg_field= lex.trg_table_fields.first;
+        for (Item_trigger_field *trg_field= sp->m_trg_table_fields.first;
              trg_field;
              trg_field= trg_field->next_trg_field)
         {