mysql: add the ability to commit transactions, some code improvements (#18268)

vlib/db/mysql/_cdefs.c.v

@@ -80,7 +80,10 @@ fn C.mysql_num_fields(res &C.MYSQL_RES) int
 fn C.mysql_num_rows(res &C.MYSQL_RES) u64
 
 // C.mysql_autocommit sets autocommit mode on if `mode` is 1, off if `mode` is 0.
-fn C.mysql_autocommit(mysql &C.MYSQL, mode bool)
+fn C.mysql_autocommit(mysql &C.MYSQL, mode bool) int
+
+// C.mysql_commit commits the current transaction.
+fn C.mysql_commit(mysql &C.MYSQL) int
 
 // C.mysql_refresh flush tables or caches, or resets replication server information.
 fn C.mysql_refresh(mysql &C.MYSQL, options u32) int

vlib/db/mysql/mysql.v

@@ -34,13 +34,13 @@ pub mut:
 }
 
 // connect attempts to establish a connection to a MySQL server.
-pub fn (mut conn Connection) connect() !bool {
-	instance := C.mysql_init(conn.conn)
-	conn.conn = C.mysql_real_connect(instance, conn.host.str, conn.username.str, conn.password.str,
-		conn.dbname.str, conn.port, 0, conn.flag)
+pub fn (mut c Connection) connect() !bool {
+	instance := C.mysql_init(c.conn)
+	c.conn = C.mysql_real_connect(instance, c.host.str, c.username.str, c.password.str,
+		c.dbname.str, c.port, 0, c.flag)
 
-	if isnil(conn.conn) {
-		return error_with_code(get_error_msg(instance), get_errno(instance))
+	if isnil(c.conn) {
+		c.throw_mysql_error()!
 	}
 
 	return true
@@ -49,12 +49,12 @@ pub fn (mut conn Connection) connect() !bool {
 // 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 (conn Connection) query(q string) !Result {
-	if C.mysql_query(conn.conn, q.str) != 0 {
-		return error_with_code(get_error_msg(conn.conn), get_errno(conn.conn))
+pub fn (c &Connection) query(q string) !Result {
+	if C.mysql_query(c.conn, q.str) != 0 {
+		c.throw_mysql_error()!
 	}
 
-	result := C.mysql_store_result(conn.conn)
+	result := C.mysql_store_result(c.conn)
 	return Result{result}
 }
 
@@ -66,8 +66,8 @@ pub fn (conn 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 (conn Connection) use_result() {
-	C.mysql_use_result(conn.conn)
+pub fn (c &Connection) use_result() {
+	C.mysql_use_result(c.conn)
 }
 
 // real_query makes an SQL query and receive the results.
@@ -75,20 +75,20 @@ pub fn (conn 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 conn Connection) real_query(q string) !Result {
-	if C.mysql_real_query(conn.conn, q.str, q.len) != 0 {
-		return error_with_code(get_error_msg(conn.conn), get_errno(conn.conn))
+pub fn (mut c Connection) real_query(q string) !Result {
+	if C.mysql_real_query(c.conn, q.str, q.len) != 0 {
+		c.throw_mysql_error()!
 	}
 
-	result := C.mysql_store_result(conn.conn)
+	result := C.mysql_store_result(c.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 conn Connection) select_db(dbname string) !bool {
-	if C.mysql_select_db(conn.conn, dbname.str) != 0 {
-		return error_with_code(get_error_msg(conn.conn), get_errno(conn.conn))
+pub fn (mut c Connection) select_db(dbname string) !bool {
+	if C.mysql_select_db(c.conn, dbname.str) != 0 {
+		c.throw_mysql_error()!
 	}
 
 	return true
@@ -97,16 +97,16 @@ pub fn (mut conn 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 conn Connection) change_user(username string, password string, dbname string) !bool {
+pub fn (mut c Connection) change_user(username string, password string, dbname string) !bool {
 	mut result := true
 
 	if dbname != '' {
-		result = C.mysql_change_user(conn.conn, username.str, password.str, dbname.str)
+		result = C.mysql_change_user(c.conn, username.str, password.str, dbname.str)
 	} else {
-		result = C.mysql_change_user(conn.conn, username.str, password.str, 0)
+		result = C.mysql_change_user(c.conn, username.str, password.str, 0)
 	}
 	if !result {
-		return error_with_code(get_error_msg(conn.conn), get_errno(conn.conn))
+		c.throw_mysql_error()!
 	}
 
 	return result
@@ -114,14 +114,29 @@ pub fn (mut conn Connection) change_user(username string, password string, dbnam
 
 // 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 (conn &Connection) affected_rows() u64 {
-	return C.mysql_affected_rows(conn.conn)
+pub fn (c &Connection) affected_rows() u64 {
+	return C.mysql_affected_rows(c.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 conn Connection) autocommit(mode bool) {
-	C.mysql_autocommit(conn.conn, mode)
+pub fn (mut c Connection) autocommit(mode bool) ! {
+	c.check_connection_is_established()!
+	result := C.mysql_autocommit(c.conn, mode)
+
+	if result != 0 {
+		c.throw_mysql_error()!
+	}
+}
+
+// commit commits the current transaction.
+pub fn (c &Connection) commit() ! {
+	c.check_connection_is_established()!
+	result := C.mysql_commit(c.conn)
+
+	if result != 0 {
+		c.throw_mysql_error()!
+	}
 }
 
 // tables returns a list of the names of the tables in the current database,
@@ -129,10 +144,10 @@ pub fn (mut conn Connection) autocommit(mode bool) {
 // 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 (conn &Connection) tables(wildcard string) ![]string {
-	c_mysql_result := C.mysql_list_tables(conn.conn, wildcard.str)
+pub fn (c &Connection) tables(wildcard string) ![]string {
+	c_mysql_result := C.mysql_list_tables(c.conn, wildcard.str)
 	if isnil(c_mysql_result) {
-		return error_with_code(get_error_msg(conn.conn), get_errno(conn.conn))
+		c.throw_mysql_error()!
 	}
 
 	result := Result{c_mysql_result}
@@ -148,10 +163,10 @@ pub fn (conn &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 (conn &Connection) escape_string(s string) string {
+pub fn (c &Connection) escape_string(s string) string {
 	unsafe {
 		to := malloc_noscan(2 * s.len + 1)
-		C.mysql_real_escape_string(conn.conn, to, s.str, s.len)
+		C.mysql_real_escape_string(c.conn, to, s.str, s.len)
 		return to.vstring()
 	}
 }
@@ -159,16 +174,16 @@ pub fn (conn &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 conn Connection) set_option(option_type int, val voidptr) {
-	C.mysql_options(conn.conn, option_type, val)
+pub fn (mut c Connection) set_option(option_type int, val voidptr) {
+	C.mysql_options(c.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 (conn &Connection) get_option(option_type int) !voidptr {
+pub fn (c &Connection) get_option(option_type int) !voidptr {
 	mysql_option := unsafe { nil }
-	if C.mysql_get_option(conn.conn, option_type, &mysql_option) != 0 {
-		return error_with_code(get_error_msg(conn.conn), get_errno(conn.conn))
+	if C.mysql_get_option(c.conn, option_type, &mysql_option) != 0 {
+		c.throw_mysql_error()!
 	}
 
 	return mysql_option
@@ -176,18 +191,18 @@ pub fn (conn &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 conn Connection) refresh(options u32) !bool {
-	if C.mysql_refresh(conn.conn, options) != 0 {
-		return error_with_code(get_error_msg(conn.conn), get_errno(conn.conn))
+pub fn (mut c Connection) refresh(options u32) !bool {
+	if C.mysql_refresh(c.conn, options) != 0 {
+		c.throw_mysql_error()!
 	}
 
 	return true
 }
 
 // reset resets the connection, and clear the session state.
-pub fn (mut conn Connection) reset() !bool {
-	if C.mysql_reset_connection(conn.conn) != 0 {
-		return error_with_code(get_error_msg(conn.conn), get_errno(conn.conn))
+pub fn (mut c Connection) reset() !bool {
+	if C.mysql_reset_connection(c.conn) != 0 {
+		c.throw_mysql_error()!
 	}
 
 	return true
@@ -195,50 +210,50 @@ pub fn (mut conn Connection) reset() !bool {
 
 // ping pings a server connection, or tries to reconnect if the connection
 // has gone down.
-pub fn (mut conn Connection) ping() !bool {
-	if C.mysql_ping(conn.conn) != 0 {
-		return error_with_code(get_error_msg(conn.conn), get_errno(conn.conn))
+pub fn (mut c Connection) ping() !bool {
+	if C.mysql_ping(c.conn) != 0 {
+		c.throw_mysql_error()!
 	}
 
 	return true
 }
 
 // close closes the connection.
-pub fn (mut conn Connection) close() {
-	C.mysql_close(conn.conn)
+pub fn (mut c Connection) close() {
+	C.mysql_close(c.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 (conn &Connection) info() string {
-	return resolve_nil_str(C.mysql_info(conn.conn))
+pub fn (c &Connection) info() string {
+	return resolve_nil_str(C.mysql_info(c.conn))
 }
 
 // get_host_info returns a string describing the type of connection in use,
 // including the server host name.
-pub fn (conn &Connection) get_host_info() string {
-	return unsafe { C.mysql_get_host_info(conn.conn).vstring() }
+pub fn (c &Connection) get_host_info() string {
+	return unsafe { C.mysql_get_host_info(c.conn).vstring() }
 }
 
 // get_server_info returns a string representing the MySQL server version.
 // For example, `8.0.24`.
-pub fn (conn &Connection) get_server_info() string {
-	return unsafe { C.mysql_get_server_info(conn.conn).vstring() }
+pub fn (c &Connection) get_server_info() string {
+	return unsafe { C.mysql_get_server_info(c.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 (conn &Connection) get_server_version() u64 {
-	return C.mysql_get_server_version(conn.conn)
+pub fn (c &Connection) get_server_version() u64 {
+	return C.mysql_get_server_version(c.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 conn Connection) dump_debug_info() !bool {
-	if C.mysql_dump_debug_info(conn.conn) != 0 {
-		return error_with_code(get_error_msg(conn.conn), get_errno(conn.conn))
+pub fn (mut c Connection) dump_debug_info() !bool {
+	if C.mysql_dump_debug_info(c.conn) != 0 {
+		c.throw_mysql_error()!
 	}
 
 	return true
@@ -261,3 +276,15 @@ pub fn get_client_version() u64 {
 pub fn debug(debug string) {
 	C.mysql_debug(debug.str)
 }
+
+[inline]
+fn (c &Connection) throw_mysql_error() ! {
+	return error_with_code(get_error_msg(c.conn), get_errno(c.conn))
+}
+
+[inline]
+fn (c &Connection) check_connection_is_established() ! {
+	if isnil(c.conn) {
+		return error('No connection to a MySQL server, use `connect()` to connect to a database for working with it')
+	}
+}