Introduction of 'Sender' and 'Destination' for Sending and Receiving

default_handler.go

@@ -117,11 +117,24 @@ type exportedMethod struct {
 	reflect.Value
 }
 
-func (m exportedMethod) Call(args ...interface{}) ([]interface{}, error) {
+func (m exportedMethod) Call(sender Sender, args ...interface{}) ([]interface{}, error) {
 	t := m.Type()
 
-	params := make([]reflect.Value, len(args))
-	for i := 0; i < len(args); i++ {
+	hasSenderParam := false
+	if m.NumArguments() > 0 && m.Type().In(0) == reflect.TypeOf(sender) {
+		hasSenderParam = true
+	}
+
+	params := make([]reflect.Value, m.NumArguments())
+
+	startIdxForArgumentsCopy := 0
+	if hasSenderParam {
+		params[0] = reflect.ValueOf(sender)
+		startIdxForArgumentsCopy = 1
+	}
+
+	for i := startIdxForArgumentsCopy; i < m.NumArguments(); i++ {
+		reflect.TypeOf(&ErrMsgInvalidArg)
 		params[i] = reflect.ValueOf(args[i]).Elem()
 	}
 

export.go

@@ -59,6 +59,9 @@ func MakeFailedError(err error) *Error {
 // sender.
 type Sender string
 
+// Destination is a type which can be used to specify a receiver for signals.
+type Destination string
+
 func computeMethodName(name string, mapping map[string]string) string {
 	newname, ok := mapping[name]
 	if ok {
@@ -190,7 +193,7 @@ func (conn *Conn) handleCall(msg *Message) {
 		return
 	}
 
-	ret, err := m.Call(args...)
+	ret, err := m.Call(Sender(sender), args...)
 	if err != nil {
 		conn.sendError(err, sender, serial)
 		return
@@ -218,6 +221,23 @@ func (conn *Conn) handleCall(msg *Message) {
 	}
 }
 
+func (conn *Conn) EmitWithDestination(path ObjectPath, name string, dest Destination, values ...interface{}) error {
+	i := strings.LastIndex(name, ".")
+	if i == -1 {
+		return errors.New("dbus: invalid method name")
+	}
+	iface := name[:i]
+	member := name[i+1:]
+
+	headers := make(map[HeaderField]Variant)
+	headers[FieldInterface] = MakeVariant(iface)
+	headers[FieldMember] = MakeVariant(member)
+	headers[FieldPath] = MakeVariant(path)
+	headers[FieldDestination] = MakeVariant(string(dest))
+
+	return conn.emitWithHeaders(headers, values...)
+}
+
 // Emit emits the given signal on the message bus. The name parameter must be
 // formatted as "interface.member", e.g., "org.freedesktop.DBus.NameLost".
 func (conn *Conn) Emit(path ObjectPath, name string, values ...interface{}) error {
@@ -227,12 +247,21 @@ func (conn *Conn) Emit(path ObjectPath, name string, values ...interface{}) erro
 	}
 	iface := name[:i]
 	member := name[i+1:]
+
+	headers := make(map[HeaderField]Variant)
+	headers[FieldInterface] = MakeVariant(iface)
+	headers[FieldMember] = MakeVariant(member)
+	headers[FieldPath] = MakeVariant(path)
+
+	return conn.emitWithHeaders(headers, values...)
+}
+
+func (conn *Conn) emitWithHeaders(headers map[HeaderField]Variant, values ...interface{}) error {
+
 	msg := new(Message)
 	msg.Type = TypeSignal
-	msg.Headers = make(map[HeaderField]Variant)
-	msg.Headers[FieldInterface] = MakeVariant(iface)
-	msg.Headers[FieldMember] = MakeVariant(member)
-	msg.Headers[FieldPath] = MakeVariant(path)
+	msg.Headers = headers
+
 	msg.Body = values
 	if len(values) > 0 {
 		msg.Headers[FieldSignature] = MakeVariant(SignatureOf(values...))

server_interfaces.go

@@ -38,7 +38,7 @@ type Interface interface {
 // A Method represents the exposed methods on D-Bus.
 type Method interface {
 	// Call requires that all arguments are decoded before being passed to it.
-	Call(args ...interface{}) ([]interface{}, error)
+	Call(sender Sender, args ...interface{}) ([]interface{}, error)
 	NumArguments() int
 	NumReturns() int
 	// ArgumentValue returns a representative value for the argument at position

server_interfaces_test.go

@@ -109,7 +109,7 @@ func (t *tester) LookupMethod(name string) (Method, bool) {
 }
 
 // Method
-func (t *tester) Call(args ...interface{}) ([]interface{}, error) {
+func (t *tester) Call(sender Sender, args ...interface{}) ([]interface{}, error) {
 	return args, nil
 }
 
@@ -131,7 +131,7 @@ func (t *tester) ReturnValue(position int) interface{} {
 
 type terrfn func(in string) error
 
-func (t terrfn) Call(args ...interface{}) ([]interface{}, error) {
+func (t terrfn) Call(sender Sender, args ...interface{}) ([]interface{}, error) {
 	return nil, t(*args[0].(*string))
 }
 
@@ -194,7 +194,7 @@ func (t *tester) RetireSerial(serial uint32) {}
 
 type intro_fn func() string
 
-func (intro intro_fn) Call(args ...interface{}) ([]interface{}, error) {
+func (intro intro_fn) Call(sender Sender, args ...interface{}) ([]interface{}, error) {
 	return []interface{}{intro()}, nil
 }