internal/pipewire: implement Core::Destroy

This change also implements pending destructible check on Sync. Destruction method should always be implemented as a wrapper of destructible.destroy.

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

internal/pipewire/pipewire.go

@@ -60,6 +60,8 @@ type Context struct {
 	pendingIds map[Int]struct{}
 	// Smallest available Id for the next proxy.
 	nextId Int
+	// Proxies targeted by the [CoreDestroy] event pending until next [CoreSync].
+	pendingDestruction map[Int]struct{}
 	// Server side registry generation number.
 	generation Long
 	// Pending file descriptors to be sent with the next message.
@@ -121,6 +123,7 @@ func New(conn Conn, props SPADict) (*Context, error) {
 		PW_ID_CLIENT: {},
 	}
 	ctx.nextId = Int(len(ctx.proxy))
+	ctx.pendingDestruction = make(map[Int]struct{})
 
 	if err := ctx.core.hello(); err != nil {
 		return nil, err
@@ -503,13 +506,21 @@ func (e DanglingFilesError) Error() string {
 }
 
 // An UnacknowledgedProxyError holds newly allocated proxy ids that the server failed
-// to acknowledge after an otherwise successful [Context.Roundtrip].
+// to acknowledge after an otherwise successful [Core.Sync].
 type UnacknowledgedProxyError []Int
 
 func (e UnacknowledgedProxyError) Error() string {
 	return "server did not acknowledge " + strconv.Itoa(len(e)) + " proxies"
 }
 
+// An UnacknowledgedProxyDestructionError holds destroyed proxy ids that the server failed
+// to acknowledge after an otherwise successful [Core.Sync].
+type UnacknowledgedProxyDestructionError []Int
+
+func (e UnacknowledgedProxyDestructionError) Error() string {
+	return "server did not acknowledge " + strconv.Itoa(len(e)) + " proxy destructions"
+}
+
 // A ProxyFatalError describes an error that terminates event handling during a
 // [Context.Roundtrip] and makes further event processing no longer possible.
 type ProxyFatalError struct {