internal/pipewire: optional final trailing garbage check

Omitting the check is only useful for custom unmarshaler.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/pipewire/client.go

@@ -50,10 +50,7 @@ type ClientInfo struct {
 func (c *ClientInfo) MarshalBinary() ([]byte, error) { return Marshal(c) }
 
 // UnmarshalBinary satisfies [encoding.BinaryUnmarshaler] via [Unmarshal].
-func (c *ClientInfo) UnmarshalBinary(data []byte) error {
+func (c *ClientInfo) UnmarshalBinary(data []byte) error { return Unmarshal(data, c) }
-	_, err := Unmarshal(data, c)
-	return err
-}
 
 // ClientUpdateProperties is used to update the properties of a client.
 type ClientUpdateProperties struct {
@@ -65,7 +62,4 @@ type ClientUpdateProperties struct {
 func (c *ClientUpdateProperties) MarshalBinary() ([]byte, error) { return Marshal(c) }
 
 // UnmarshalBinary satisfies [encoding.BinaryUnmarshaler] via [Unmarshal].
-func (c *ClientUpdateProperties) UnmarshalBinary(data []byte) error {
+func (c *ClientUpdateProperties) UnmarshalBinary(data []byte) error { return Unmarshal(data, c) }
-	_, err := Unmarshal(data, c)
-	return err
-}

internal/pipewire/core.go

@@ -106,10 +106,7 @@ type CoreInfo struct {
 func (c *CoreInfo) MarshalBinary() ([]byte, error) { return Marshal(c) }
 
 // UnmarshalBinary satisfies [encoding.BinaryUnmarshaler] via [Unmarshal].
-func (c *CoreInfo) UnmarshalBinary(data []byte) error {
+func (c *CoreInfo) UnmarshalBinary(data []byte) error { return Unmarshal(data, c) }
-	_, err := Unmarshal(data, c)
-	return err
-}
 
 // The CoreBoundProps event is emitted when a local object ID is bound to a global ID.
 // It is emitted before the global becomes visible in the registry.
@@ -126,10 +123,7 @@ type CoreBoundProps struct {
 func (c *CoreBoundProps) MarshalBinary() ([]byte, error) { return Marshal(c) }
 
 // UnmarshalBinary satisfies [encoding.BinaryUnmarshaler] via [Unmarshal].
-func (c *CoreBoundProps) UnmarshalBinary(data []byte) error {
+func (c *CoreBoundProps) UnmarshalBinary(data []byte) error { return Unmarshal(data, c) }
-	_, err := Unmarshal(data, c)
-	return err
-}
 
 // CoreHello is the first message sent by a client.
 type CoreHello struct {
@@ -143,10 +137,7 @@ func (c *CoreHello) MarshalBinary() ([]byte, error) {
 }
 
 // UnmarshalBinary satisfies [encoding.BinaryUnmarshaler] via [Unmarshal].
-func (c *CoreHello) UnmarshalBinary(data []byte) error {
+func (c *CoreHello) UnmarshalBinary(data []byte) error { return Unmarshal(data, c) }
-	_, err := Unmarshal(data, c)
-	return err
-}
 
 const (
 	// CoreSyncSequenceOffset is the offset to [Header.Sequence] to produce [CoreSync.Sequence].
@@ -157,11 +148,9 @@ const (
 // When the Done event is received, the client can be sure that all
 // operations before the Sync method have been completed.
 type CoreSync struct {
-	// The id will be returned in the Done event,
+	// The id will be returned in the Done event.
-	// ends up as [Header.ID] in a future message.
 	ID Int
-	// Usually generated automatically and will be
+	// Usually generated automatically and will be returned in the Done event.
-	// returned in the Done event.
 	Sequence Int
 }
 
@@ -171,10 +160,7 @@ func (c *CoreSync) MarshalBinary() ([]byte, error) {
 }
 
 // UnmarshalBinary satisfies [encoding.BinaryUnmarshaler] via [Unmarshal].
-func (c *CoreSync) UnmarshalBinary(data []byte) error {
+func (c *CoreSync) UnmarshalBinary(data []byte) error { return Unmarshal(data, c) }
-	_, err := Unmarshal(data, c)
-	return err
-}
 
 // CoreGetRegistry is sent when a client requests to bind to the
 // registry object and list the available objects on the server.
@@ -197,7 +183,4 @@ func (c *CoreGetRegistry) MarshalBinary() ([]byte, error) {
 }
 
 // UnmarshalBinary satisfies [encoding.BinaryUnmarshaler] via [Unmarshal].
-func (c *CoreGetRegistry) UnmarshalBinary(data []byte) error {
+func (c *CoreGetRegistry) UnmarshalBinary(data []byte) error { return Unmarshal(data, c) }
-	_, err := Unmarshal(data, c)
-	return err
-}

internal/pipewire/pod.go

@@ -204,7 +204,19 @@ func (e *InvalidUnmarshalError) Error() string {
 // Unmarshal parses the PipeWire POD encoded data and stores the result
 // in the value pointed to by v. If v is nil or not a pointer,
 // Unmarshal returns an [InvalidUnmarshalError].
-func Unmarshal(data []byte, v any) (size Word, err error) {
+func Unmarshal(data []byte, v any) error {
+	if n, err := UnmarshalNext(data, v); err != nil {
+		return err
+	} else if len(data) > int(n) {
+		return &TrailingGarbageError{data[int(n):]}
+	}
+
+	return nil
+}
+
+// UnmarshalNext implements [Unmarshal] but returns the size of message decoded
+// and skips the final trailing garbage check.
+func UnmarshalNext(data []byte, v any) (size Word, err error) {
 	rv := reflect.ValueOf(v)
 	if rv.Kind() != reflect.Pointer || rv.IsNil() {
 		return 0, &InvalidUnmarshalError{reflect.TypeOf(v)}
@@ -399,10 +411,7 @@ type Footer[T any] struct {
 func (f *Footer[T]) MarshalBinary() ([]byte, error) { return Marshal(f) }
 
 // UnmarshalBinary satisfies [encoding.BinaryUnmarshaler] via [Unmarshal].
-func (f *Footer[T]) UnmarshalBinary(data []byte) error {
+func (f *Footer[T]) UnmarshalBinary(data []byte) error { return Unmarshal(data, f) }
-	_, err := Unmarshal(data, f)
-	return err
-}
 
 // SPADictItem is an encoding-compatible representation of spa_dict_item.
 type SPADictItem struct{ Key, Value string }
@@ -445,7 +454,7 @@ func (d *SPADict) UnmarshalPOD(data []byte) (Word, error) {
 	// bounds check completed in successful call to unmarshalCheckTypeBounds
 	data = data[:wireSize]
 
-	if size, err := Unmarshal(data, &d.NItems); err != nil {
+	if size, err := UnmarshalNext(data, &d.NItems); err != nil {
 		return wireSize, err
 	} else {
 		// bounds check completed in successful call to Unmarshal
@@ -454,13 +463,13 @@ func (d *SPADict) UnmarshalPOD(data []byte) (Word, error) {
 
 	d.Items = make([]SPADictItem, d.NItems)
 	for i := range d.Items {
-		if size, err := Unmarshal(data, &d.Items[i].Key); err != nil {
+		if size, err := UnmarshalNext(data, &d.Items[i].Key); err != nil {
 			return wireSize, err
 		} else {
 			// bounds check completed in successful call to Unmarshal
 			data = data[size:]
 		}
-		if size, err := Unmarshal(data, &d.Items[i].Value); err != nil {
+		if size, err := UnmarshalNext(data, &d.Items[i].Value); err != nil {
 			return wireSize, err
 		} else {
 			// bounds check completed in successful call to Unmarshal