[Tarantool-patches] [PATCH v2 07/16] port: add dump format and request type to port_sql

[Nikita Pettik <korablev@tarantool.org>]

Dump formats of DQL and DML queries are different: the last one contains
number of affected rows and optionally list of autoincremented ids; the
first one comprises all meta-information including column names of
resulting set and their types. What is more, dump format is going to be
different for execute and prepare requests. So let's introduce separate
member to struct port_sql responsible for dump format to be used.

What is more, prepared statement finalization is required only for
PREPARE-AND-EXECUTE requests. So let's keep request type in port as well.

Note that C standard specifies that enums are integers, but it does not
specify the size. Hence, let's use simple uint8 - mentioned enums are
small enough to fit into it.

Needed for #2592
---
 src/box/execute.c     | 32 +++++++++++++++++++++++---------
 src/box/execute.h     | 24 ++++++++++++++++++++++++
 src/box/lua/execute.c | 20 +++++++++++++-------
 3 files changed, 60 insertions(+), 16 deletions(-)

diff --git a/src/box/execute.c b/src/box/execute.c
index 83680b70f..d2a999099 100644
--- a/src/box/execute.c
+++ b/src/box/execute.c
@@ -100,7 +100,9 @@ static void
 port_sql_destroy(struct port *base)
 {
 	port_tuple_vtab.destroy(base);
-	sql_finalize(((struct port_sql *)base)->stmt);
+	struct port_sql *port_sql = (struct port_sql *) base;
+	if (port_sql->request == PREPARE_AND_EXECUTE)
+		sql_finalize(((struct port_sql *)base)->stmt);
 }
 
 const struct port_vtab port_sql_vtab = {
@@ -114,11 +116,15 @@ const struct port_vtab port_sql_vtab = {
 };
 
 static void
-port_sql_create(struct port *port, struct sql_stmt *stmt)
+port_sql_create(struct port *port, struct sql_stmt *stmt,
+		enum sql_dump_format dump_format, enum sql_request_type request)
 {
 	port_tuple_create(port);
-	((struct port_sql *)port)->stmt = stmt;
 	port->vtab = &port_sql_vtab;
+	struct port_sql *port_sql = (struct port_sql *) port;
+	port_sql->stmt = stmt;
+	port_sql->dump_format = dump_format;
+	port_sql->request = request;
 }
 
 /**
@@ -324,9 +330,10 @@ port_sql_dump_msgpack(struct port *port, struct obuf *out)
 {
 	assert(port->vtab == &port_sql_vtab);
 	sql *db = sql_get();
-	struct sql_stmt *stmt = ((struct port_sql *)port)->stmt;
-	int column_count = sql_column_count(stmt);
-	if (column_count > 0) {
+	struct port_sql *sql_port = (struct port_sql *)port;
+	struct sql_stmt *stmt = sql_port->stmt;
+	switch (sql_port->dump_format) {
+	case DQL_EXECUTE: {
 		int keys = 2;
 		int size = mp_sizeof_map(keys);
 		char *pos = (char *) obuf_alloc(out, size);
@@ -335,7 +342,7 @@ port_sql_dump_msgpack(struct port *port, struct obuf *out)
 			return -1;
 		}
 		pos = mp_encode_map(pos, keys);
-		if (sql_get_metadata(stmt, out, column_count) != 0)
+		if (sql_get_metadata(stmt, out, sql_column_count(stmt)) != 0)
 			return -1;
 		size = mp_sizeof_uint(IPROTO_DATA);
 		pos = (char *) obuf_alloc(out, size);
@@ -346,7 +353,9 @@ port_sql_dump_msgpack(struct port *port, struct obuf *out)
 		pos = mp_encode_uint(pos, IPROTO_DATA);
 		if (port_tuple_vtab.dump_msgpack(port, out) < 0)
 			return -1;
-	} else {
+		break;
+	}
+	case DML_EXECUTE: {
 		int keys = 1;
 		assert(((struct port_tuple *)port)->size == 0);
 		struct stailq *autoinc_id_list =
@@ -395,6 +404,9 @@ port_sql_dump_msgpack(struct port *port, struct obuf *out)
 				      mp_encode_int(buf, id_entry->id);
 			}
 		}
+		break;
+	}
+	default: unreachable();
 	}
 	return 0;
 }
@@ -445,7 +457,9 @@ sql_prepare_and_execute(const char *sql, int len, const struct sql_bind *bind,
 	if (sql_compile(sql, len, NULL, &stmt, NULL) != 0)
 		return -1;
 	assert(stmt != NULL);
-	port_sql_create(port, stmt);
+	enum sql_dump_format dump_format = sql_column_count(stmt) > 0 ?
+					   DQL_EXECUTE : DML_EXECUTE;
+	port_sql_create(port, stmt, dump_format, PREPARE_AND_EXECUTE);
 	if (sql_bind(stmt, bind, bind_count) == 0 &&
 	    sql_execute(stmt, port, region) == 0)
 		return 0;
diff --git a/src/box/execute.h b/src/box/execute.h
index a85fca5fc..6702a18cc 100644
--- a/src/box/execute.h
+++ b/src/box/execute.h
@@ -46,6 +46,23 @@ enum sql_info_key {
 	sql_info_key_MAX,
 };
 
+/**
+ * One of possible formats used to dump msgpack/Lua.
+ * For details see port_sql_dump_msgpack() and port_sql_dump_lua().
+ */
+enum sql_dump_format {
+	DQL_EXECUTE = 0,
+	DML_EXECUTE = 1,
+	DQL_PREPARE = 2,
+	DML_PREPARE = 3,
+};
+
+enum sql_request_type {
+	PREPARE_AND_EXECUTE = 0,
+	PREPARE = 1,
+	EXECUTE_PREPARED = 2
+};
+
 extern const char *sql_info_key_strs[];
 
 struct region;
@@ -85,6 +102,13 @@ struct port_sql {
 	struct port_tuple port_tuple;
 	/* Prepared SQL statement. */
 	struct sql_stmt *stmt;
+	/**
+	 * Dump format depends on type of SQL query: DML or DQL;
+	 * and on type of SQL request: execute or prepare.
+	 */
+	uint8_t dump_format;
+	/** enum sql_request_type */
+	uint8_t request;
 };
 
 extern const struct port_vtab port_sql_vtab;
diff --git a/src/box/lua/execute.c b/src/box/lua/execute.c
index 76ecdd541..1b2f8d235 100644
--- a/src/box/lua/execute.c
+++ b/src/box/lua/execute.c
@@ -45,18 +45,21 @@ port_sql_dump_lua(struct port *port, struct lua_State *L, bool is_flat)
 	assert(is_flat == false);
 	assert(port->vtab == &port_sql_vtab);
 	struct sql *db = sql_get();
-	struct sql_stmt *stmt = ((struct port_sql *)port)->stmt;
-	int column_count = sql_column_count(stmt);
-	if (column_count > 0) {
+	struct port_sql *port_sql = (struct port_sql *)port;
+	struct sql_stmt *stmt = port_sql->stmt;
+	switch (port_sql->dump_format) {
+	case DQL_EXECUTE: {
 		lua_createtable(L, 0, 2);
-		lua_sql_get_metadata(stmt, L, column_count);
+		lua_sql_get_metadata(stmt, L, sql_column_count(stmt));
 		lua_setfield(L, -2, "metadata");
 		port_tuple_vtab.dump_lua(port, L, false);
 		lua_setfield(L, -2, "rows");
-	} else {
-		assert(((struct port_tuple *)port)->size == 0);
+		break;
+	}
+	case DML_EXECUTE: {
+		assert(((struct port_tuple *) port)->size == 0);
 		struct stailq *autoinc_id_list =
-			vdbe_autoinc_id_list((struct Vdbe *)stmt);
+			vdbe_autoinc_id_list((struct Vdbe *) stmt);
 		lua_createtable(L, 0, stailq_empty(autoinc_id_list) ? 1 : 2);
 
 		luaL_pushuint64(L, db->nChange);
@@ -77,6 +80,9 @@ port_sql_dump_lua(struct port *port, struct lua_State *L, bool is_flat)
 				sql_info_key_strs[SQL_INFO_AUTOINCREMENT_IDS];
 			lua_setfield(L, -2, field_name);
 		}
+		break;
+	}
+	default: unreachable();
 	}
 }
 
-- 
2.15.1