mysql: simplify, add more functionality & documentation

vlib/mysql/_cdefs.c.v

@@ -33,7 +33,9 @@ fn C.mysql_change_user(mysql &C.MYSQL, user byteptr, password byteptr, db bytept
 fn C.mysql_affected_rows(mysql &C.MYSQL) u64
 fn C.mysql_options(mysql &C.MYSQL, option int, arg voidptr) int
 fn C.mysql_get_option(mysql &C.MYSQL, option int, arg voidptr) int
+fn C.mysql_list_tables(mysql &C.MYSQL, wild byteptr) &C.MYSQL_RES
 fn C.mysql_num_fields(res &C.MYSQL_RES) int
+fn C.mysql_num_rows(res &C.MYSQL_RES) u64
 fn C.mysql_autocommit(mysql MYSQL, mode bool)
 fn C.mysql_refresh(mysql MYSQL, options u32) int
 fn C.mysql_reset_connection(mysql MYSQL) int

vlib/mysql/mysql.v

@@ -4,35 +4,24 @@ module mysql
 #flag linux -I/usr/include/mysql
 #include <mysql.h>
 
+// TODO: Documentation
 pub struct Connection {
-	host     string
-	port     u32
+mut:
+	conn     &C.MYSQL = C.mysql_init(0)
+pub mut:
+	host     string		= '127.0.0.1'
+	port     u32		= 3306
 	username string
 	password string
 	dbname   string
 	flag     int
-mut:
-	conn     &C.MYSQL
-}
-
-pub fn new_connection(host, username, password, dbname string) ?Connection {
-	instance := C.mysql_init(0)
-	if isnil(instance) {
-		return error_with_code(get_error_msg(instance), get_errno(instance))
-	}
-	return Connection{ host, 0, username, password, dbname, 0, instance }
 }
 
+// connect Connects to a MySQL server
 pub fn (mut conn Connection) connect() ?bool {
-	mut instance := C.mysql_init(0)
-	if !isnil(conn.conn) {
-		instance = conn.conn
-	}
-	if isnil(instance) {
-		return error_with_code(get_error_msg(instance), get_errno(instance))
-	}
+	instance := C.mysql_init(conn.conn)
 	conn.conn = C.mysql_real_connect(
-		instance,
+		conn.conn,
 		conn.host.str,
 		conn.username.str,
 		conn.password.str,
@@ -47,6 +36,7 @@ pub fn (mut conn Connection) connect() ?bool {
 	return true
 }
 
+// query Performs a query on the database
 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))
@@ -55,6 +45,7 @@ pub fn (conn Connection) query(q string) ?Result {
 	return Result{res}
 }
 
+// select_db Selects the default database for database queries
 pub fn (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))
@@ -62,6 +53,9 @@ pub fn (conn Connection) select_db(dbname string) ?bool {
 	return true
 }
 
+// change_user Changes the user of the specified database connection.
+// If desired, the empty string value can be passed to the `dbname` parameter
+// resulting in only changing the user and not selecting a database
 pub fn (conn Connection) change_user(username, password, dbname string) ?bool {
 	mut ret := true
 	if dbname != '' {
@@ -75,15 +69,34 @@ pub fn (conn Connection) change_user(username, password, dbname string) ?bool {
 	return ret
 }
 
+// affected_rows Returns the number of rows changed/deleted/inserted
+// by the last UPDATE, DELETE, or INSERT query
 pub fn (conn Connection) affected_rows() u64 {
 	return C.mysql_affected_rows(conn.conn)
 }
 
+// autocommit Turns on or off auto-committing database modifications
 pub fn (conn Connection) autocommit(mode bool) {
 	C.mysql_autocommit(conn.conn, mode)
 }
 
+// tables Returns list of tables that match the `wildcard` parameter.
+// If empty string is passed, will return all tables
+pub fn (conn Connection) tables(wildcard string) ?[]string {
+	cres := C.mysql_list_tables(conn.conn, wildcard.str)
+	if isnil(cres) {
+		return error_with_code(get_error_msg(conn.conn), get_errno(conn.conn))
+	}
+	res :=  Result{cres}
+	mut tables := []string{}
+	for row in res.rows() {
+		tables << row.vals[0]
+	}
+	res.free()
+	return tables
+}
 
+// escape_string Creates a legal SQL string for use in an SQL statement
 pub fn (conn Connection) escape_string(s string) string {
     len := C.strlen(s.str)
     to := malloc(2 * len + 1)
@@ -93,10 +106,15 @@ pub fn (conn Connection) escape_string(s string) string {
     return string(to)
 }
 
+// set_option Can be used to set extra connect options and affect behavior for a connection.
+// This function may be called multiple times to set several options.
+// To retrieve option values, use `get_option()`
 pub fn (conn Connection) set_option(option_type int, val voidptr) {
 	C.mysql_options(conn.conn, option_type, val)
 }
 
+// get_option Returns the current value of an option settable `set_option`.
+// The value should be treated as read only
 pub fn (conn Connection) get_option(option_type int) ?voidptr {
 	ret := voidptr(0)
 	if C.mysql_get_option(conn.conn, option_type, &ret) != 0 {
@@ -105,6 +123,8 @@ pub fn (conn Connection) get_option(option_type int) ?voidptr {
 	return ret
 }
 
+// refresh Flushes tables or caches, or resets replication server information.
+// The connected user must have the `RELOAD` privilege
 pub fn (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))
@@ -112,6 +132,7 @@ pub fn (conn Connection) refresh(options u32) ?bool {
 	return true
 }
 
+// reset_connection Resets the connection to clear the session state
 pub fn (conn Connection) reset_connection() ?bool {
 	if C.mysql_reset_connection(conn.conn) != 0 {
 		return error_with_code(get_error_msg(conn.conn), get_errno(conn.conn))
@@ -119,6 +140,7 @@ pub fn (conn Connection) reset_connection() ?bool {
 	return true
 }
 
+// ping Pings a server connection, or tries to reconnect if the connection has gone down
 pub fn (conn Connection) ping() ?bool {
 	if C.mysql_ping(conn.conn) != 0 {
 		return error_with_code(get_error_msg(conn.conn), get_errno(conn.conn))
@@ -126,37 +148,48 @@ pub fn (conn Connection) ping() ?bool {
 	return true
 }
 
-pub fn (conn Connection) close() {
+// close Closes a previously opened database connection
+pub fn (conn &Connection) close() {
 	C.mysql_close(conn.conn)
 }
 
-/* MYSQL INFO & VERSION */
+/* -------------------------- MYSQL INFO & VERSION -------------------------- */
 
+// info Returns information about the most recently executed query
 pub fn (conn Connection) info() string {
-	return string(C.mysql_info(conn.conn))
+	return resolve_nil_str(C.mysql_info(conn.conn))
 }
 
+// get_host_info Returns a string describing the connection
 pub fn (conn Connection) get_host_info() string {
 	return string(C.mysql_get_host_info(conn.conn))
 }
 
+// get_server_info Returns the server version number as a string
 pub fn (conn Connection) get_server_info() string {
 	return string(C.mysql_get_server_info(conn.conn))
 }
 
+// get_server_version Returns the server version number as an integer
 pub fn (conn Connection) get_server_version() u64 {
 	return C.mysql_get_server_version(conn.conn)
 }
 
-pub fn get_client_version() u64 {
-	return C.mysql_get_client_version()
-}
+/* --------------------------------- CLIENT --------------------------------- */
 
+// get_client_info Returns client version information as a string
 pub fn get_client_info() string {
 	return string(C.mysql_get_client_info())
 }
 
-/* MYSQL DEBUG */
+// get_client_version Returns client version information as an integer
+pub fn get_client_version() u64 {
+	return C.mysql_get_client_version()
+}
+
+/* ------------------------------- MYSQL DEBUG ------------------------------ */
+
+// dump_debug_info Causes the server to write debug information to the log
 pub fn (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))
@@ -164,6 +197,8 @@ pub fn (conn Connection) dump_debug_info() ?bool {
 	return true
 }
 
+// debug Does a `DBUG_PUSH` with the given string.
+// See https://dev.mysql.com/doc/refman/5.7/en/mysql-debug.html
 pub fn debug(debug string) {
 	C.mysql_debug(debug.str)
 }

vlib/mysql/result.v

@@ -9,37 +9,22 @@ pub mut:
 	vals []string
 }
 
-pub struct Field {
-	name             string
-	org_name         string
-	table            string
-	org_table        string
-	db               string
-	catalog          string
-	def              string
-	length           int
-	max_length       int
-	name_length      u32
-	org_name_length  u32
-	table_length     u32
-	org_table_length u32
-	db_length        u32
-	catalog_length   u32
-	def_length       u32
-	flags            u32
-	decimals         u32
-	charsetnr        u32
-	type_            FieldType
-}
-
+// Fetches the next row from the result set
 pub fn (r Result) fetch_row() &byteptr {
 	return C.mysql_fetch_row(r.result)
 }
 
+// num_rows Returns the number of rows in the result set
+pub fn (r Result) num_rows() u64 {
+	return C.mysql_num_rows(r.result)
+}
+
+// num_fields Returns the number of columns in a result set
 pub fn (r Result) num_fields() int {
 	return C.mysql_num_fields(r.result)
 }
 
+// rows Returns rows with `array` of columns
 pub fn (r Result) rows() []Row {
 	mut rows := []Row{}
 	nr_cols := r.num_fields()
@@ -57,7 +42,7 @@ pub fn (r Result) rows() []Row {
 	return rows
 }
 
-// maps return rows with `map` of columns instead `array` of columns
+// maps Returns rows with `map` of columns instead `array` of columns
 pub fn (r Result) maps() []map[string]string {
 	mut array_map := []map[string]string{}
 	rows := r.rows()
@@ -72,6 +57,7 @@ pub fn (r Result) maps() []map[string]string {
 	return array_map
 }
 
+// fetch_fields Returns an array of all field structures
 pub fn (r Result) fetch_fields() []Field {
 	mut fields := []Field{}
 	nr_cols := r.num_fields()
@@ -103,6 +89,29 @@ pub fn (r Result) fetch_fields() []Field {
 	return fields
 }
 
+pub struct Field {
+	name             string
+	org_name         string
+	table            string
+	org_table        string
+	db               string
+	catalog          string
+	def              string
+	length           int
+	max_length       int
+	name_length      u32
+	org_name_length  u32
+	table_length     u32
+	org_table_length u32
+	db_length        u32
+	catalog_length   u32
+	def_length       u32
+	flags            u32
+	decimals         u32
+	charsetnr        u32
+	type_            FieldType
+}
+
 pub fn (f Field) str() string {
 	return '
 {
@@ -130,6 +139,7 @@ pub fn (f Field) str() string {
 '
 }
 
+// free Frees memory used by a result set
 pub fn (r Result) free() {
 	C.mysql_free_result(r.result)
 }