lua: create vstream implementation for Lua

Thas patch creates vstream implementation for Lua and function
box.sql.new_execute() that uses this implementation. Also it
creates parameters binding for SQL statements executed through
box.

Part of #3505
Closes #3401

src/CMakeLists.txt

@@ -182,6 +182,7 @@ set (server_sources
      lua/crypto.c
      lua/httpc.c
      lua/utf8.c
+     lua/luastream.c
      ${lua_sources}
      ${PROJECT_SOURCE_DIR}/third_party/lua-yaml/lyaml.cc
      ${PROJECT_SOURCE_DIR}/third_party/lua-yaml/b64.c

src/box/execute.c

@@ -43,6 +43,8 @@
 #include "tuple.h"
 #include "sql/vdbe.h"
 #include "vstream.h"
+#include "lua/utils.h"
+#include "lua/msgpack.h"
 
 const char *sql_type_strs[] = {
 	NULL,
@@ -298,6 +300,195 @@ xrow_decode_sql(const struct xrow_header *row, struct sql_request *request,
 	return 0;
 }
 
+/**
+ * Decode a single bind column from Lua stack.
+ *
+ * @param L Lua stack.
+ * @param[out] bind Bind to decode to.
+ * @param idx Position of table with bind columns on Lua stack.
+ * @param i Ordinal bind number.
+ *
+ * @retval  0 Success.
+ * @retval -1 Memory or client error.
+ */
+static inline int
+lua_sql_bind_decode(struct lua_State *L, struct sql_bind *bind, int idx, int i)
+{
+	struct luaL_field field;
+	char *buf;
+	lua_rawgeti(L, idx, i + 1);
+	luaL_tofield(L, luaL_msgpack_default, -1, &field);
+	bind->pos = i + 1;
+	if (field.type == MP_MAP) {
+		/*
+		 * A named parameter is an MP_MAP with
+		 * one key - {'name': value}.
+		 * Report parse error otherwise.
+		 */
+		if (field.size != 1) {
+			diag_set(ClientError, ER_ILLEGAL_PARAMS, "SQL bind "\
+				 "parameter should be {'name': value}");
+			return -1;
+		}
+		/*
+		 * Get key and value of the only map element to
+		 * lua stack.
+		 */
+		lua_pushnil(L);
+		lua_next(L, lua_gettop(L) - 1);
+		/* At first we should deal with the value. */
+		luaL_tofield(L, luaL_msgpack_default, -1, &field);
+		lua_pop(L, 1);
+		/* Now key is on the top of Lua stack. */
+		size_t name_len = 0;
+		bind->name = luaL_checklstring(L, -1, &name_len);
+		if (bind->name == NULL) {
+			diag_set(ClientError, ER_ILLEGAL_PARAMS, "SQL bind "\
+				 "parameter should be {'name': value}");
+			return -1;
+		}
+		/*
+		 * Name should be saved in allocated memory as it
+		 * will be poped from Lua stack.
+		 */
+		buf = region_alloc(&fiber()->gc, name_len + 1);
+		if (buf == NULL) {
+			diag_set(OutOfMemory, name_len + 1, "region_alloc",
+				 "buf");
+			return -1;
+		}
+		memcpy(buf, bind->name, name_len + 1);
+		bind->name = buf;
+		bind->name_len = name_len;
+		lua_pop(L, 1);
+	} else {
+		bind->name = NULL;
+		bind->name_len = 0;
+	}
+	switch (field.type) {
+	case MP_UINT: {
+		bind->i64 = field.ival;
+		bind->type = SQLITE_INTEGER;
+		bind->bytes = sizeof(bind->i64);
+		break;
+	}
+	case MP_INT:
+		bind->i64 = field.ival;
+		bind->type = SQLITE_INTEGER;
+		bind->bytes = sizeof(bind->i64);
+		break;
+	case MP_STR:
+		/*
+		 * Data should be saved in allocated memory as it
+		 * will be poped from Lua stack.
+		 */
+		buf = region_alloc(&fiber()->gc, field.sval.len + 1);
+		if (buf == NULL) {
+			diag_set(OutOfMemory, field.sval.len + 1,
+				 "region_alloc", "buf");
+			return -1;
+		}
+		memcpy(buf, field.sval.data, field.sval.len + 1);
+		bind->s = buf;
+		bind->type = SQLITE_TEXT;
+		bind->bytes = field.sval.len;
+		break;
+	case MP_DOUBLE:
+		bind->d = field.dval;
+		bind->type = SQLITE_FLOAT;
+		bind->bytes = sizeof(bind->d);
+		break;
+	case MP_FLOAT:
+		bind->d = field.dval;
+		bind->type = SQLITE_FLOAT;
+		bind->bytes = sizeof(bind->d);
+		break;
+	case MP_NIL:
+		bind->type = SQLITE_NULL;
+		bind->bytes = 1;
+		break;
+	case MP_BOOL:
+		/* SQLite doesn't support boolean. Use int instead. */
+		bind->i64 = field.bval ? 1 : 0;
+		bind->type = SQLITE_INTEGER;
+		bind->bytes = sizeof(bind->i64);
+		break;
+	case MP_BIN:
+		bind->s = mp_decode_bin(&field.sval.data, &bind->bytes);
+		bind->type = SQLITE_BLOB;
+		break;
+	case MP_EXT:
+		/*
+		 * Data should be saved in allocated memory as it
+		 * will be poped from Lua stack.
+		 */
+		buf = region_alloc(&fiber()->gc, sizeof(field));
+		if (buf == NULL) {
+			diag_set(OutOfMemory, sizeof(field), "region_alloc",
+				 "buf");
+			return -1;
+		}
+		memcpy(buf, &field, sizeof(field));
+		bind->s = buf;
+		bind->bytes = sizeof(field);
+		bind->type = SQLITE_BLOB;
+		break;
+	case MP_ARRAY:
+		diag_set(ClientError, ER_SQL_BIND_TYPE, "ARRAY",
+			 sql_bind_name(bind));
+		return -1;
+	case MP_MAP:
+		diag_set(ClientError, ER_SQL_BIND_TYPE, "MAP",
+			 sql_bind_name(bind));
+		return -1;
+	default:
+		unreachable();
+	}
+	lua_pop(L, 1);
+	return 0;
+}
+
+int
+lua_sql_bind_list_decode(struct lua_State *L, struct sql_request *request,
+			 int idx)
+{
+	assert(request != NULL);
+	if (! lua_istable(L, idx)) {
+		diag_set(ClientError, ER_INVALID_MSGPACK, "SQL parameter list");
+		return -1;
+	}
+	uint32_t bind_count = lua_objlen(L, idx);
+	if (bind_count == 0)
+		return 0;
+	if (bind_count > SQL_BIND_PARAMETER_MAX) {
+		diag_set(ClientError, ER_SQL_BIND_PARAMETER_MAX,
+			 (int) bind_count);
+		return -1;
+	}
+	struct region *region = &fiber()->gc;
+	uint32_t used = region_used(region);
+	size_t size = sizeof(struct sql_bind) * bind_count;
+	/*
+	 * Memory allocated here will be freed in
+	 * sqlite3_finalize() or in txn_commit()/txn_rollback() if
+	 * there is an active transaction.
+	 */
+	struct sql_bind *bind = (struct sql_bind *) region_alloc(region, size);
+	if (bind == NULL) {
+		diag_set(OutOfMemory, size, "region_alloc", "bind");
+		return -1;
+	}
+	for (uint32_t i = 0; i < bind_count; ++i) {
+		if (lua_sql_bind_decode(L, &bind[i], idx, i) != 0) {
+			region_truncate(region, used);
+			return -1;
+		}
+	}
+	request->bind_count = bind_count;
+	request->bind = bind;
+	return 0;
+}
+
 /**
  * Serialize a single column of a result set row.
  * @param stmt Prepared and started statement. At least one

src/box/execute.h

@@ -52,6 +52,7 @@ struct region;
 struct sql_bind;
 struct xrow_header;
 struct vstream;
+struct lua_State;
 
 /** EXECUTE request. */
 struct sql_request {
@@ -141,6 +142,20 @@ int
 xrow_decode_sql(const struct xrow_header *row, struct sql_request *request,
 		struct region *region);
 
+/**
+ * Parse Lua table of SQL parameters and store a result
+ * into the @request->bind, bind_count.
+ * @param L Lua stack to get data from.
+ * @param request Request to save decoded parameters.
+ * @param idx Position of table with parameters on Lua stack.
+ *
+ * @retval  0 Success.
+ * @retval -1 Client or memory error.
+ */
+int
+lua_sql_bind_list_decode(struct lua_State *L, struct sql_request *request,
+			 int idx);
+
 /**
  * Prepare and execute an SQL statement.
  * @param request IProto request.

src/box/lua/sql.c

@@ -5,7 +5,10 @@
 #include "box/sql/sqliteInt.h"
 #include "box/info.h"
 #include "lua/utils.h"
+#include "lua/luastream.h"
 #include "info.h"
+#include "box/execute.h"
+#include "vstream.h"
 
 static void
 lua_push_column_names(struct lua_State *L, struct sqlite3_stmt *stmt)
@@ -110,6 +113,38 @@ lua_sql_execute(struct lua_State *L)
 	return lua_error(L);
 }
 
+static int
+lbox_execute(struct lua_State *L)
+{
+	struct sqlite3 *db = sql_get();
+	if (db == NULL)
+		return luaL_error(L, "not ready");
+
+	size_t length;
+	const char *sql = lua_tolstring(L, 1, &length);
+	if (sql == NULL)
+		return luaL_error(L, "usage: box.execute(sqlstring)");
+
+	struct sql_request request = {};
+	request.sql_text = sql;
+	request.sql_text_len = length;
+	if (lua_gettop(L) == 2 && lua_sql_bind_list_decode(L, &request, 2) != 0)
+		return luaT_error(L);
+	struct sql_response response = {.is_info_flattened = true};
+	if (sql_prepare_and_execute(&request, &response, &fiber()->gc) != 0)
+		return luaT_error(L);
+
+	int keys;
+	struct vstream vstream;
+	luavstream_init(&vstream, L);
+	lua_newtable(L);
+	if (sql_response_dump(&response, &keys, &vstream) != 0) {
+		lua_pop(L, 1);
+		return luaT_error(L);
+	}
+	return 1;
+}
+
 static int
 lua_sql_debug(struct lua_State *L)
 {
@@ -124,6 +159,7 @@ box_lua_sqlite_init(struct lua_State *L)
 {
 	static const struct luaL_Reg module_funcs [] = {
 		{"execute", lua_sql_execute},
+		{"new_execute", lbox_execute},
 		{"debug", lua_sql_debug},
 		{NULL, NULL}
 	};

src/box/lua/sql.h

@@ -36,9 +36,13 @@ extern "C" {
 #endif
 
 struct lua_State;
+struct luastream;
 
 void box_lua_sqlite_init(struct lua_State *L);
 
+void
+luastream_init(struct luastream *stream, struct lua_State *L);
+
 #ifdef __cplusplus
 }
 #endif