mysql: connection fixes (#18428)

examples/database/mysql.v

@@ -1,14 +1,13 @@
 import db.mysql
 
 fn main() {
-	mut conn := mysql.Connection{
+	mut conn := mysql.connect(
 		host: 'localhost'
 		port: 3306
 		username: 'root'
 		password: ''
 		dbname: 'mysql'
-	}
+	)!
-	conn.connect()!
 	res := conn.query('show tables')!
 	for row in res.rows() {
 		println(row.vals.join(', '))

examples/database/orm.v

@@ -102,14 +102,13 @@ fn sqlite3_array() ! {
 
 fn msql_array() ! {
 	eprintln('------------ ${@METHOD} -----------------')
-	mut db := mysql.Connection{
+	mut db := mysql.connect(
 		host: mysql_host
 		port: mysql_port
 		username: mysql_user
 		password: mysql_pass
 		dbname: mysql_db
-	}
+	)!
-	db.connect()!
 	defer {
 		sql db {
 			drop table Parent
@@ -213,14 +212,13 @@ fn sqlite3() ! {
 
 fn msql() ! {
 	eprintln('------------ ${@METHOD} -----------------')
-	mut conn := mysql.Connection{
+	mut conn := mysql.connect(
 		host: mysql_host
 		port: mysql_port
 		username: mysql_user
 		password: mysql_pass
 		dbname: mysql_db
-	}
+	)!
-	conn.connect()!
 	defer {
 		conn.query('DROP TABLE IF EXISTS Module') or { eprintln(err) }
 		conn.query('DROP TABLE IF EXISTS User') or { eprintln(err) }

vlib/db/mysql/mysql.v

@@ -21,7 +21,12 @@ struct SQLError {
 	MessageError
 }
 
-pub struct Connection {
+pub struct DB {
+mut:
+	conn &C.MYSQL = unsafe { nil }
+}
+
+pub struct Config {
 mut:
 	conn &C.MYSQL = C.mysql_init(0)
 pub mut:
@@ -34,27 +39,35 @@ pub mut:
 }
 
 // connect attempts to establish a connection to a MySQL server.
-pub fn (mut c Connection) connect() !bool {
+pub fn connect(config Config) !DB {
-	instance := C.mysql_init(c.conn)
+	mut db := DB{
-	c.conn = C.mysql_real_connect(instance, c.host.str, c.username.str, c.password.str,
+		conn: C.mysql_init(0)
-		c.dbname.str, c.port, 0, c.flag)
-
-	if isnil(c.conn) {
-		c.throw_mysql_error()!
 	}
 
-	return true
+	connection := C.mysql_real_connect(db.conn, config.host.str, config.username.str,
+		config.password.str, config.dbname.str, config.port, 0, config.flag)
+
+	if isnil(connection) {
+		db.throw_mysql_error()!
+	}
+
+	// Sets `db.conn` after checking for `null`
+	// because `throw_mysql_error` can't extract an error from a `null` connection,
+	// and `panic` will be with an empty message.
+	db.conn = connection
+
+	return db
 }
 
 // query executes the SQL statement pointed to by the string `q`.
 // It cannot be used for statements that contain binary data;
 // Use `real_query()` instead.
-pub fn (c &Connection) query(q string) !Result {
+pub fn (db &DB) query(q string) !Result {
-	if C.mysql_query(c.conn, q.str) != 0 {
+	if C.mysql_query(db.conn, q.str) != 0 {
-		c.throw_mysql_error()!
+		db.throw_mysql_error()!
 	}
 
-	result := C.mysql_store_result(c.conn)
+	result := C.mysql_store_result(db.conn)
 	return Result{result}
 }
 
@@ -66,8 +79,8 @@ pub fn (c &Connection) query(q string) !Result {
 // without storing it in a temporary table or local buffer,
 // mysql_use_result is faster and uses much less memory than C.mysql_store_result().
 // You must mysql_free_result() after you are done with the result set.
-pub fn (c &Connection) use_result() {
+pub fn (db &DB) use_result() {
-	C.mysql_use_result(c.conn)
+	C.mysql_use_result(db.conn)
 }
 
 // real_query makes an SQL query and receive the results.
@@ -75,20 +88,20 @@ pub fn (c &Connection) use_result() {
 // (Binary data may contain the `\0` character, which `query()`
 // interprets as the end of the statement string). In addition,
 // `real_query()` is faster than `query()`.
-pub fn (mut c Connection) real_query(q string) !Result {
+pub fn (mut db DB) real_query(q string) !Result {
-	if C.mysql_real_query(c.conn, q.str, q.len) != 0 {
+	if C.mysql_real_query(db.conn, q.str, q.len) != 0 {
-		c.throw_mysql_error()!
+		db.throw_mysql_error()!
 	}
 
-	result := C.mysql_store_result(c.conn)
+	result := C.mysql_store_result(db.conn)
 	return Result{result}
 }
 
 // select_db causes the database specified by `db` to become
 // the default (current) database on the connection specified by mysql.
-pub fn (mut c Connection) select_db(dbname string) !bool {
+pub fn (mut db DB) select_db(dbname string) !bool {
-	if C.mysql_select_db(c.conn, dbname.str) != 0 {
+	if C.mysql_select_db(db.conn, dbname.str) != 0 {
-		c.throw_mysql_error()!
+		db.throw_mysql_error()!
 	}
 
 	return true
@@ -97,16 +110,16 @@ pub fn (mut c Connection) select_db(dbname string) !bool {
 // change_user changes the mysql user for the connection.
 // Passing an empty string for the `dbname` parameter, resultsg in only changing
 // the user and not changing the default database for the connection.
-pub fn (mut c Connection) change_user(username string, password string, dbname string) !bool {
+pub fn (mut db DB) change_user(username string, password string, dbname string) !bool {
 	mut result := true
 
 	if dbname != '' {
-		result = C.mysql_change_user(c.conn, username.str, password.str, dbname.str)
+		result = C.mysql_change_user(db.conn, username.str, password.str, dbname.str)
 	} else {
-		result = C.mysql_change_user(c.conn, username.str, password.str, 0)
+		result = C.mysql_change_user(db.conn, username.str, password.str, 0)
 	}
 	if !result {
-		c.throw_mysql_error()!
+		db.throw_mysql_error()!
 	}
 
 	return result
@@ -114,28 +127,28 @@ pub fn (mut c Connection) change_user(username string, password string, dbname s
 
 // affected_rows returns the number of rows changed, deleted,
 // or inserted by the last statement if it was an `UPDATE`, `DELETE`, or `INSERT`.
-pub fn (c &Connection) affected_rows() u64 {
+pub fn (db &DB) affected_rows() u64 {
-	return C.mysql_affected_rows(c.conn)
+	return C.mysql_affected_rows(db.conn)
 }
 
 // autocommit turns on/off the auto-committing mode for the connection.
 // When it is on, then each query is committed right away.
-pub fn (mut c Connection) autocommit(mode bool) ! {
+pub fn (mut db DB) autocommit(mode bool) ! {
-	c.check_connection_is_established()!
+	db.check_connection_is_established()!
-	result := C.mysql_autocommit(c.conn, mode)
+	result := C.mysql_autocommit(db.conn, mode)
 
 	if result != 0 {
-		c.throw_mysql_error()!
+		db.throw_mysql_error()!
 	}
 }
 
 // commit commits the current transaction.
-pub fn (c &Connection) commit() ! {
+pub fn (db &DB) commit() ! {
-	c.check_connection_is_established()!
+	db.check_connection_is_established()!
-	result := C.mysql_commit(c.conn)
+	result := C.mysql_commit(db.conn)
 
 	if result != 0 {
-		c.throw_mysql_error()!
+		db.throw_mysql_error()!
 	}
 }
 
@@ -144,10 +157,10 @@ pub fn (c &Connection) commit() ! {
 // The `wildcard` parameter may contain the wildcard characters `%` or `_`.
 // If an empty string is passed, it will return all tables.
 // Calling `tables()` is similar to executing query `SHOW TABLES [LIKE wildcard]`.
-pub fn (c &Connection) tables(wildcard string) ![]string {
+pub fn (db &DB) tables(wildcard string) ![]string {
-	c_mysql_result := C.mysql_list_tables(c.conn, wildcard.str)
+	c_mysql_result := C.mysql_list_tables(db.conn, wildcard.str)
 	if isnil(c_mysql_result) {
-		c.throw_mysql_error()!
+		db.throw_mysql_error()!
 	}
 
 	result := Result{c_mysql_result}
@@ -163,10 +176,10 @@ pub fn (c &Connection) tables(wildcard string) ![]string {
 // escape_string creates a legal SQL string for use in an SQL statement.
 // The `s` argument is encoded to produce an escaped SQL string,
 // taking into account the current character set of the connection.
-pub fn (c &Connection) escape_string(s string) string {
+pub fn (db &DB) escape_string(s string) string {
 	unsafe {
 		to := malloc_noscan(2 * s.len + 1)
-		C.mysql_real_escape_string(c.conn, to, s.str, s.len)
+		C.mysql_real_escape_string(db.conn, to, s.str, s.len)
 		return to.vstring()
 	}
 }
@@ -174,16 +187,16 @@ pub fn (c &Connection) escape_string(s string) string {
 // set_option sets extra connect options that affect the behavior of
 // a connection. This function may be called multiple times to set several
 // options. To retrieve the current values for an option, use `get_option()`.
-pub fn (mut c Connection) set_option(option_type int, val voidptr) {
+pub fn (mut db DB) set_option(option_type int, val voidptr) {
-	C.mysql_options(c.conn, option_type, val)
+	C.mysql_options(db.conn, option_type, val)
 }
 
 // get_option returns the value of an option, settable by `set_option`.
 // https://dev.mysql.com/doc/c-api/5.7/en/mysql-get-option.html
-pub fn (c &Connection) get_option(option_type int) !voidptr {
+pub fn (db &DB) get_option(option_type int) !voidptr {
 	mysql_option := unsafe { nil }
-	if C.mysql_get_option(c.conn, option_type, &mysql_option) != 0 {
+	if C.mysql_get_option(db.conn, option_type, &mysql_option) != 0 {
-		c.throw_mysql_error()!
+		db.throw_mysql_error()!
 	}
 
 	return mysql_option
@@ -191,18 +204,18 @@ pub fn (c &Connection) get_option(option_type int) !voidptr {
 
 // refresh flush the tables or caches, or resets replication server
 // information. The connected user must have the `RELOAD` privilege.
-pub fn (mut c Connection) refresh(options u32) !bool {
+pub fn (mut db DB) refresh(options u32) !bool {
-	if C.mysql_refresh(c.conn, options) != 0 {
+	if C.mysql_refresh(db.conn, options) != 0 {
-		c.throw_mysql_error()!
+		db.throw_mysql_error()!
 	}
 
 	return true
 }
 
 // reset resets the connection, and clear the session state.
-pub fn (mut c Connection) reset() !bool {
+pub fn (mut db DB) reset() !bool {
-	if C.mysql_reset_connection(c.conn) != 0 {
+	if C.mysql_reset_connection(db.conn) != 0 {
-		c.throw_mysql_error()!
+		db.throw_mysql_error()!
 	}
 
 	return true
@@ -210,50 +223,50 @@ pub fn (mut c Connection) reset() !bool {
 
 // ping pings a server connection, or tries to reconnect if the connection
 // has gone down.
-pub fn (mut c Connection) ping() !bool {
+pub fn (mut db DB) ping() !bool {
-	if C.mysql_ping(c.conn) != 0 {
+	if C.mysql_ping(db.conn) != 0 {
-		c.throw_mysql_error()!
+		db.throw_mysql_error()!
 	}
 
 	return true
 }
 
 // close closes the connection.
-pub fn (mut c Connection) close() {
+pub fn (mut db DB) close() {
-	C.mysql_close(c.conn)
+	C.mysql_close(db.conn)
 }
 
 // info returns information about the most recently executed query.
 // See more on https://dev.mysql.com/doc/c-api/8.0/en/mysql-info.html
-pub fn (c &Connection) info() string {
+pub fn (db &DB) info() string {
-	return resolve_nil_str(C.mysql_info(c.conn))
+	return resolve_nil_str(C.mysql_info(db.conn))
 }
 
 // get_host_info returns a string describing the type of connection in use,
 // including the server host name.
-pub fn (c &Connection) get_host_info() string {
+pub fn (db &DB) get_host_info() string {
-	return unsafe { C.mysql_get_host_info(c.conn).vstring() }
+	return unsafe { C.mysql_get_host_info(db.conn).vstring() }
 }
 
 // get_server_info returns a string representing the MySQL server version.
 // For example, `8.0.24`.
-pub fn (c &Connection) get_server_info() string {
+pub fn (db &DB) get_server_info() string {
-	return unsafe { C.mysql_get_server_info(c.conn).vstring() }
+	return unsafe { C.mysql_get_server_info(db.conn).vstring() }
 }
 
 // get_server_version returns an integer, representing the MySQL server
 // version. The value has the format `XYYZZ` where `X` is the major version,
 // `YY` is the release level (or minor version), and `ZZ` is the sub-version
 // within the release level. For example, `8.0.24` is returned as `80024`.
-pub fn (c &Connection) get_server_version() u64 {
+pub fn (db &DB) get_server_version() u64 {
-	return C.mysql_get_server_version(c.conn)
+	return C.mysql_get_server_version(db.conn)
 }
 
 // dump_debug_info instructs the server to write debugging information
 // to the error log. The connected user must have the `SUPER` privilege.
-pub fn (mut c Connection) dump_debug_info() !bool {
+pub fn (mut db DB) dump_debug_info() !bool {
-	if C.mysql_dump_debug_info(c.conn) != 0 {
+	if C.mysql_dump_debug_info(db.conn) != 0 {
-		c.throw_mysql_error()!
+		db.throw_mysql_error()!
 	}
 
 	return true
@@ -278,13 +291,13 @@ pub fn debug(debug string) {
 }
 
 [inline]
-fn (c &Connection) throw_mysql_error() ! {
+fn (db &DB) throw_mysql_error() ! {
-	return error_with_code(get_error_msg(c.conn), get_errno(c.conn))
+	return error_with_code(get_error_msg(db.conn), get_errno(db.conn))
 }
 
 [inline]
-fn (c &Connection) check_connection_is_established() ! {
+fn (db &DB) check_connection_is_established() ! {
-	if isnil(c.conn) {
+	if isnil(db.conn) {
 		return error('No connection to a MySQL server, use `connect()` to connect to a database for working with it')
 	}
 }

vlib/db/mysql/mysql_orm_test.v

@@ -36,14 +36,13 @@ struct TestDefaultAtribute {
 }
 
 fn test_mysql_orm() {
-	mut db := mysql.Connection{
+	mut db := mysql.connect(
 		host: 'localhost'
 		port: 3306
 		username: 'root'
 		password: ''
 		dbname: 'mysql'
-	}
+	)!
-	db.connect() or { panic(err) }
 	defer {
 		db.close()
 	}
@@ -124,7 +123,6 @@ fn test_mysql_orm() {
 		WHERE TABLE_NAME = 'TestCustomSqlType'
 		ORDER BY ORDINAL_POSITION
 	") or {
-		println(err)
 		panic(err)
 	}
 

vlib/db/mysql/orm.v

@@ -4,7 +4,7 @@ import orm
 import time
 
 // @select is used internally by V's ORM for processing `SELECT ` queries.
-pub fn (db Connection) @select(config orm.SelectConfig, data orm.QueryData, where orm.QueryData) ![][]orm.Primitive {
+pub fn (db DB) @select(config orm.SelectConfig, data orm.QueryData, where orm.QueryData) ![][]orm.Primitive {
 	query := orm.orm_select_gen(config, '`', false, '?', 0, where)
 	mut result := [][]orm.Primitive{}
 	mut stmt := db.init_stmt(query)
@@ -128,7 +128,7 @@ pub fn (db Connection) @select(config orm.SelectConfig, data orm.QueryData, wher
 }
 
 // insert is used internally by V's ORM for processing `INSERT ` queries
-pub fn (db Connection) insert(table string, data orm.QueryData) ! {
+pub fn (db DB) insert(table string, data orm.QueryData) ! {
 	mut converted_primitive_array := db.convert_query_data_to_primitives(table, data)!
 
 	converted_primitive_data := orm.QueryData{
@@ -145,20 +145,20 @@ pub fn (db Connection) insert(table string, data orm.QueryData) ! {
 }
 
 // update is used internally by V's ORM for processing `UPDATE ` queries
-pub fn (db Connection) update(table string, data orm.QueryData, where orm.QueryData) ! {
+pub fn (db DB) update(table string, data orm.QueryData, where orm.QueryData) ! {
 	query, _ := orm.orm_stmt_gen(.default, table, '`', .update, false, '?', 1, data, where)
 	mysql_stmt_worker(db, query, data, where)!
 }
 
 // delete is used internally by V's ORM for processing `DELETE ` queries
-pub fn (db Connection) delete(table string, where orm.QueryData) ! {
+pub fn (db DB) delete(table string, where orm.QueryData) ! {
 	query, _ := orm.orm_stmt_gen(.default, table, '`', .delete, false, '?', 1, orm.QueryData{},
 		where)
 	mysql_stmt_worker(db, query, orm.QueryData{}, where)!
 }
 
 // last_id is used internally by V's ORM for post-processing `INSERT ` queries
-pub fn (db Connection) last_id() int {
+pub fn (db DB) last_id() int {
 	query := 'SELECT last_insert_id();'
 	id := db.query(query) or { return 0 }
 
@@ -166,7 +166,7 @@ pub fn (db Connection) last_id() int {
 }
 
 // create is used internally by V's ORM for processing table creation queries (DDL)
-pub fn (db Connection) create(table string, fields []orm.TableField) ! {
+pub fn (db DB) create(table string, fields []orm.TableField) ! {
 	query := orm.orm_table_gen(table, '`', true, 0, fields, mysql_type_from_v, false) or {
 		return err
 	}
@@ -174,7 +174,7 @@ pub fn (db Connection) create(table string, fields []orm.TableField) ! {
 }
 
 // drop is used internally by V's ORM for processing table destroying queries (DDL)
-pub fn (db Connection) drop(table string) ! {
+pub fn (db DB) drop(table string) ! {
 	query := 'DROP TABLE `${table}`;'
 	mysql_stmt_worker(db, query, orm.QueryData{}, orm.QueryData{})!
 }
@@ -182,7 +182,7 @@ pub fn (db Connection) drop(table string) ! {
 // mysql_stmt_worker executes the `query` with the provided `data` and `where` parameters
 // without returning the result.
 // This is commonly used for `INSERT`, `UPDATE`, `CREATE`, `DROP`, and `DELETE` queries.
-fn mysql_stmt_worker(db Connection, query string, data orm.QueryData, where orm.QueryData) ! {
+fn mysql_stmt_worker(db DB, query string, data orm.QueryData, where orm.QueryData) ! {
 	mut stmt := db.init_stmt(query)
 	stmt.prepare()!
 
@@ -360,7 +360,7 @@ fn mysql_type_from_v(typ int) !string {
 
 // convert_query_data_to_primitives converts the `data` representing the `QueryData`
 // into an array of `Primitive`.
-fn (db Connection) convert_query_data_to_primitives(table string, data orm.QueryData) ![]orm.Primitive {
+fn (db DB) convert_query_data_to_primitives(table string, data orm.QueryData) ![]orm.Primitive {
 	mut column_type_map := db.get_table_column_type_map(table)!
 	mut converted_data := []orm.Primitive{}
 
@@ -381,7 +381,7 @@ fn (db Connection) convert_query_data_to_primitives(table string, data orm.Query
 
 // get_table_column_type_map returns a map where the key represents the column name,
 // and the value represents its data type.
-fn (db Connection) get_table_column_type_map(table string) !map[string]string {
+fn (db DB) get_table_column_type_map(table string) !map[string]string {
 	data_type_query := "SELECT COLUMN_NAME, DATA_TYPE FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = '${table}'"
 	mut column_type_map := map[string]string{}
 	results := db.query(data_type_query)!

vlib/db/mysql/stmt.c.v

@@ -77,7 +77,7 @@ pub fn (s &Stmt) str() string {
 }
 
 // init_stmt creates a new statement, given the `query`.
-pub fn (db Connection) init_stmt(query string) Stmt {
+pub fn (db DB) init_stmt(query string) Stmt {
 	return Stmt{
 		stmt: C.mysql_stmt_init(db.conn)
 		query: query