box: don't apply space upgrade func to DML result except for DELETE

There's no need to apply a space upgrade function to the tuple returned
by INSERT, REPLACE, UPDATE, or UPSERT, because it must match the new
format anyway. We only need to process tuples returned by DELETE
requests. That being said, let's move the result processing from
box_process_rw() to memtx_space_execute_delete(). Note, we don't need to
patch vinyl_space_execute_delete(), because in Vinyl DELETE doesn't
return the deleted tuple.

Follow-up commit 21e2def ("box: introduce result processor").

NO_DOC=refactoring
NO_TEST=refactoring
NO_CHANGELOG=refactoring

Author: locker

src/box/box.cc

@@ -307,8 +307,6 @@ box_process_rw(struct request *request, struct space *space,
 	bool return_tuple = false;
 	struct txn *txn = in_txn();
 	bool is_autocommit = txn == NULL;
-	struct result_processor res_proc;
-	int rc;
 	if (is_autocommit && (txn = txn_begin()) == NULL)
 		return -1;
 	assert(iproto_type_is_dml(request->type));
@@ -317,19 +315,14 @@ box_process_rw(struct request *request, struct space *space,
 		goto rollback;
 	if (txn_begin_stmt(txn, space, request->type) != 0)
 		goto rollback;
-	result_process_prepare(&res_proc, space);
-	rc = space_execute_dml(space, txn, request, &tuple);
-	if (result == NULL)
-		tuple = NULL;
-	result_process_perform(&res_proc, &rc, &tuple);
-	if (rc != 0) {
+	if (space_execute_dml(space, txn, request, &tuple) != 0) {
 		txn_rollback_stmt(txn);
 		goto rollback;
 	}
 	if (result != NULL)
 		*result = tuple;
 
-	return_tuple = tuple != NULL;
+	return_tuple = result != NULL && tuple != NULL;
 	if (return_tuple) {
 		/*
 		 * Pin the tuple locally before the commit,

src/box/memtx_space.c

@@ -45,6 +45,7 @@
 #include "sequence.h"
 #include "memtx_tuple_compression.h"
 #include "schema.h"
+#include "result.h"
 
 /*
  * Yield every 1K tuples while building a new index or checking
@@ -437,8 +438,8 @@ memtx_space_execute_delete(struct space *space, struct txn *txn,
 	if (memtx_space_replace_tuple(space, stmt, old_tuple, NULL,
 				      DUP_REPLACE_OR_INSERT) != 0)
 		return -1;
-	*result = stmt->old_tuple;
-	return 0;
+	*result = result_process(space, stmt->old_tuple);
+	return *result == NULL ? -1 : 0;
 }
 
 static int

src/box/result.h

@@ -60,6 +60,23 @@ result_process_perform(struct result_processor *p, int *rc,
 	space_upgrade_unref(p->upgrade);
 }
 
+/**
+ * A shortcut for
+ *
+ *   int rc = 0;
+ *   struct result_processor res_proc;
+ *   result_process_prepare(&res_proc, space);
+ *   result_process_perform(&res_proc, &rc, &tuple);
+ */
+static inline struct tuple *
+result_process(struct space *space, struct tuple *tuple)
+{
+	if (unlikely(space->upgrade != NULL))
+		return space_upgrade_apply(space->upgrade, tuple);
+	else
+		return tuple;
+}
+
 #if defined(__cplusplus)
 } /* extern "C" */
 #endif /* defined(__cplusplus) */