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feat(discovery): remember receivers independently of IP #197

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45 changes: 45 additions & 0 deletions TargetBridge-Receiver/TBReceiverC/src/main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -88,6 +88,7 @@ struct app {
char net_ip_text[64];
char ethernet_ip_text[64];
char wifi_ip_text[64];
char receiver_id[64];
char display_host[128]; /* short hostname (or hostname+IP), cached at startup */
char status_text[128];
char sender_text[128];
Expand Down Expand Up @@ -574,6 +575,41 @@ static void bonjour_deinit(struct app *a) {
}
}

static int tb_receiver_load_or_create_id(char *dest, size_t size, CFStringRef app_id) {
if (!dest || size == 0) return -1;
dest[0] = '\0';
if (size < 37 || !app_id) return -1;

CFStringRef key = CFSTR("receiverID");
CFPropertyListRef stored = CFPreferencesCopyAppValue(key, app_id);
CFUUIDRef uuid = NULL;
if (stored && CFGetTypeID(stored) == CFStringGetTypeID() &&
CFStringGetLength((CFStringRef)stored) == 36) {
uuid = CFUUIDCreateFromString(kCFAllocatorDefault, (CFStringRef)stored);
}
if (stored) CFRelease(stored);

const Boolean needs_persistence = uuid == NULL;
if (!uuid) uuid = CFUUIDCreate(kCFAllocatorDefault);
if (!uuid) return -1;
CFStringRef value = CFUUIDCreateString(kCFAllocatorDefault, uuid);
CFRelease(uuid);
if (!value) return -1;

const Boolean copied = CFStringGetCString(value, dest, (CFIndex)size, kCFStringEncodingUTF8);
Boolean persisted = true;
if (copied && dest[0] != '\0' && needs_persistence) {
CFPreferencesSetAppValue(key, value, app_id);
persisted = CFPreferencesAppSynchronize(app_id);
}
CFRelease(value);
if (!copied || !persisted) {
dest[0] = '\0';
return -1;
}
return dest[0] != '\0' ? 0 : -1;
}

static void on_bonjour_register(DNSServiceRef sdRef,
DNSServiceFlags flags,
DNSServiceErrorType errorCode,
Expand All @@ -599,6 +635,9 @@ static void bonjour_update(struct app *a, uint16_t port) {
TXTRecordRef txt;
TXTRecordCreate(&txt, 0, NULL);
TXTRecordSetValue(&txt, "name", (uint8_t)strlen(a->bonjour_name), a->bonjour_name);
if (a->receiver_id[0] != '\0') {
TXTRecordSetValue(&txt, "receiverID", (uint8_t)strlen(a->receiver_id), a->receiver_id);
}
TXTRecordSetValue(&txt, "ip", (uint8_t)strlen(a->ip_text), a->ip_text);
if (a->tb_ip_text[0] != '\0') {
TXTRecordSetValue(&txt, "tbIP", (uint8_t)strlen(a->tb_ip_text), a->tb_ip_text);
Expand Down Expand Up @@ -1960,6 +1999,12 @@ int main(int argc, char **argv) {
memset(&a, 0, sizeof(a));
a.server_fd = -1;
a.client_fd = -1;
if (tb_receiver_load_or_create_id(a.receiver_id, sizeof(a.receiver_id),
CFSTR("com.targetbridge.receiver")) == 0) {
fprintf(stderr, "[identity] receiver ID ready\n");
} else {
fprintf(stderr, "[identity] unable to persist receiver ID; using Bonjour name fallback\n");
}
{
char host[96] = {0};
if (gethostname(host, sizeof(host)) != 0 || host[0] == '\0') {
Expand Down
97 changes: 85 additions & 12 deletions TargetBridge-Sender/TBDisplaySender/TBDisplaySenderAutomation.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -193,9 +193,24 @@ enum TBSenderAutomation {
}

let receiver = params["receiver"].flatMap { $0.isEmpty ? nil : $0 } ?? "auto"
let discoveredReceivers = await waitForReceivers(
service,
preferredIdentity: receiver.lowercased() == "auto"
? session.selectedReceiverID
: receiver
)
if receiver.lowercased() == "auto" {
guard let discovered = await waitForReceiver(service) else {
NSLog("[automation] no receivers discovered; aborting connect")
guard let discovered = automaticReceiver(
in: discoveredReceivers,
preferredIdentity: session.selectedReceiverID
) else {
if !session.selectedReceiverID.isEmpty {
NSLog("[automation] preferred monitor unavailable or ambiguous; waiting for that monitor")
} else if discoveredReceivers.count > 1 {
NSLog("[automation] multiple receivers discovered and no preferred monitor is selected; waiting for user choice")
} else {
NSLog("[automation] no receivers discovered; aborting connect")
}
return nil
}
if let pathPreference {
Expand All @@ -211,8 +226,7 @@ enum TBSenderAutomation {
} else {
service.applyDiscoveredReceiver(discovered, to: session)
}
session.selectedReceiverID = discovered.id
} else if let discovered = service.discoveredReceivers.first(where: { matches(receiver, $0) }) {
} else if let discovered = discoveredReceivers.first(where: { matches(receiver, $0) }) {
if let pathPreference {
guard let selected = await selectConnectionPath(
receiver: discovered,
Expand All @@ -226,8 +240,11 @@ enum TBSenderAutomation {
} else {
service.applyDiscoveredReceiver(discovered, to: session)
}
session.selectedReceiverID = discovered.id
} else {
guard !isPersistedReceiverReference(receiver) else {
NSLog("[automation] requested monitor identity is not available; aborting connect")
return nil
}
// Treat as a raw IP / hostname (bypasses Bonjour).
session.receiverIP = receiver
session.selectedReceiverID = ""
Expand Down Expand Up @@ -329,13 +346,69 @@ enum TBSenderAutomation {
return nil
}

/// Discovery is async (Bonjour); briefly wait for the first receiver to appear.
private static func waitForReceiver(_ service: TBDisplaySenderService) async -> TBDiscoveredReceiver? {
for _ in 0..<20 {
if let first = service.discoveredReceivers.first { return first }
try? await Task.sleep(nanoseconds: 300_000_000)
/// Bonjour results arrive incrementally. Waiting for a short settled window
/// prevents `auto` from connecting to whichever of several displays happens
/// to advertise first. A previously selected stable identity may return
/// immediately because it is unambiguous.
private static func waitForReceivers(
_ service: TBDisplaySenderService,
preferredIdentity: String
) async -> [TBDiscoveredReceiver] {
var lastSignature: [String] = []
var unchangedIterations = 0
var firstNonEmptyIteration: Int?

for iteration in 0..<24 {
let receivers = service.discoveredReceivers
if !preferredIdentity.isEmpty,
receivers.contains(where: { $0.matchesPersistedIdentity(preferredIdentity) }) {
return receivers
}

if !receivers.isEmpty {
if firstNonEmptyIteration == nil { firstNonEmptyIteration = iteration }
let signature = receivers
.map { "\($0.stableIdentity)|\($0.preferredIP)" }
.sorted()
if signature == lastSignature {
unchangedIterations += 1
} else {
lastSignature = signature
unchangedIterations = 0
}

if let firstNonEmptyIteration,
iteration - firstNonEmptyIteration >= 6,
unchangedIterations >= 3 {
return receivers
}
}
try? await Task.sleep(nanoseconds: 250_000_000)
}
return service.discoveredReceivers.first
return service.discoveredReceivers
}

/// Automatic startup is safe only when the preferred display is present or
/// exactly one Receiver exists and no preference was saved. With multiple unpaired displays, returning
/// nil is intentional: silently choosing the first one would send the user's
/// desktop to the wrong Mac.
static func automaticReceiver(
in receivers: [TBDiscoveredReceiver],
preferredIdentity: String
) -> TBDiscoveredReceiver? {
if !preferredIdentity.isEmpty {
let preferred = receivers.filter {
$0.matchesPersistedIdentity(preferredIdentity)
}
return preferred.count == 1 ? preferred[0] : nil
}
return receivers.count == 1 ? receivers[0] : nil
}

static func isPersistedReceiverReference(_ value: String) -> Bool {
let value = value.trimmingCharacters(in: .whitespacesAndNewlines).lowercased()
return value.hasPrefix("receiver:") || value.hasPrefix("service:") ||
value.contains("|") || UUID(uuidString: value) != nil
}

private static func selectConnectionPath(
Expand Down Expand Up @@ -425,7 +498,7 @@ enum TBSenderAutomation {
// unit-test bundle can exercise them directly.
static func matches(_ value: String, _ receiver: TBDiscoveredReceiver) -> Bool {
let needle = value.lowercased()
if receiver.id.lowercased() == needle { return true }
if receiver.matchesPersistedIdentity(needle) { return true }
if receiver.receiverName.lowercased() == needle { return true }
if let host = receiver.shortHostName?.lowercased(), host == needle { return true }
return receiver.preferredIP.lowercased() == needle
Expand Down
12 changes: 6 additions & 6 deletions TargetBridge-Sender/TBDisplaySender/TBDisplaySenderManager.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -474,6 +474,7 @@ final class TBDisplaySenderService: ObservableObject {
}

func applyDiscoveredReceiver(_ receiver: TBDiscoveredReceiver, to session: TBDisplaySenderSession) {
session.selectedReceiverID = receiver.stableIdentity
session.receiverIP = receiver.ip(for: session.transportKind)
session.receiverSupportsHEVCDecodeHint = receiver.supportsHEVCDecode
if session.localInterfaceIP.isEmpty {
Expand All @@ -493,16 +494,13 @@ final class TBDisplaySenderService: ObservableObject {
!session.selectedReceiverID.isEmpty &&
!session.isConnected &&
!session.isStreaming {
let savedServiceName = String(
session.selectedReceiverID.split(separator: "|", maxSplits: 1).first ?? ""
)
guard let receiver = receivers.first(where: {
$0.id == session.selectedReceiverID || $0.serviceName == savedServiceName
$0.matchesPersistedIdentity(session.selectedReceiverID)
}) else {
continue
}

session.selectedReceiverID = receiver.id
session.selectedReceiverID = receiver.stableIdentity
session.receiverIP = receiver.ip(for: session.transportKind)
session.receiverSupportsHEVCDecodeHint = receiver.supportsHEVCDecode
}
Expand Down Expand Up @@ -570,7 +568,9 @@ final class TBDisplaySenderService: ObservableObject {

func transportDidChange(for session: TBDisplaySenderSession) {
session.localInterfaceIP = defaultLocalInterfaceIP(for: session.transportKind)
if let receiver = discoveredReceivers.first(where: { $0.id == session.selectedReceiverID }) {
if let receiver = discoveredReceivers.first(where: {
$0.matchesPersistedIdentity(session.selectedReceiverID)
}) {
session.receiverIP = receiver.ip(for: session.transportKind)
}
objectWillChange.send()
Expand Down
15 changes: 10 additions & 5 deletions TargetBridge-Sender/TBDisplaySender/TBDisplaySenderService.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -1082,7 +1082,7 @@ final class TBDisplaySenderSession: NSObject, ObservableObject, Identifiable, @u
}
var shortHostName: String? {
if let receiver = TBDisplaySenderService.shared.discoveredReceivers.first(where: {
$0.id == selectedReceiverID ||
$0.matchesPersistedIdentity(selectedReceiverID) ||
$0.preferredIP == receiverIP ||
$0.thunderboltIP == receiverIP ||
$0.networkIP == receiverIP
Expand Down Expand Up @@ -1767,7 +1767,7 @@ final class TBDisplaySenderSession: NSObject, ObservableObject, Identifiable, @u
// changes. Using the address here made macOS forget a receiver's virtual
// display identity and saved placement after a wake or reconnect.
if let receiver = TBDisplaySenderService.shared.discoveredReceivers.first(where: {
$0.id == selectedReceiverID ||
$0.matchesPersistedIdentity(selectedReceiverID) ||
$0.preferredIP == receiverIP ||
$0.thunderboltIP == receiverIP ||
$0.networkIP == receiverIP
Expand All @@ -1776,9 +1776,14 @@ final class TBDisplaySenderSession: NSObject, ObservableObject, Identifiable, @u
}

let selectedID = selectedReceiverID.trimmingCharacters(in: .whitespacesAndNewlines)
if let serviceName = selectedID.split(separator: "|", maxSplits: 1).first,
!serviceName.isEmpty {
return "service:\(serviceName)"
if !selectedID.isEmpty {
if selectedID.hasPrefix("receiver:") || selectedID.hasPrefix("service:") {
return selectedID
}
if let serviceName = selectedID.split(separator: "|", maxSplits: 1).first,
!serviceName.isEmpty {
return "service:\(serviceName)"
}
}

if let host = shortHostName?.trimmingCharacters(in: .whitespacesAndNewlines),
Expand Down
46 changes: 41 additions & 5 deletions TargetBridge-Sender/TBDisplaySender/TBReceiverDiscovery.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@ import Foundation
struct TBDiscoveredReceiver: Identifiable, Equatable {
let serviceName: String
let receiverName: String
let receiverID: String
let preferredIP: String
let thunderboltIP: String
let usbIP: String
Expand All @@ -18,6 +19,7 @@ struct TBDiscoveredReceiver: Identifiable, Equatable {
init(
serviceName: String,
receiverName: String,
receiverID: String = "",
preferredIP: String,
thunderboltIP: String,
usbIP: String = "",
Expand All @@ -32,6 +34,7 @@ struct TBDiscoveredReceiver: Identifiable, Equatable {
) {
self.serviceName = serviceName
self.receiverName = receiverName
self.receiverID = UUID(uuidString: receiverID)?.uuidString ?? ""
self.preferredIP = preferredIP
self.thunderboltIP = thunderboltIP
self.usbIP = usbIP
Expand All @@ -45,11 +48,37 @@ struct TBDiscoveredReceiver: Identifiable, Equatable {
self.hostName = hostName
}

var id: String { "\(serviceName)|\(preferredIP)" }
/// SwiftUI selection and persisted sessions both use this stable identity.
/// New receivers advertise a UUID; older receivers fall back to their
/// Bonjour service name so existing installations remain selectable.
var id: String { stableIdentity }

/// Bonjour service names survive link-local IP address changes after wake.
/// Use this only for persisted receiver preferences, not Picker selection.
var stableIdentity: String { "service:\(serviceName)" }
var legacyID: String { "\(serviceName)|\(preferredIP)" }

/// Stable across network changes, and across renaming for UUID receivers.
var stableIdentity: String {
receiverID.isEmpty ? "service:\(serviceName)" : "receiver:\(receiverID)"
}

/// Accept the stable UUID, the previous service-name identity, and the
/// oldest `service|ip` picker value. This migrates saved sessions without
/// ever treating a changed IP as a different physical display.
func matchesPersistedIdentity(_ value: String) -> Bool {
let needle = value.trimmingCharacters(in: .whitespacesAndNewlines).lowercased()
guard !needle.isEmpty else { return false }

if needle == id.lowercased() ||
needle == stableIdentity.lowercased() ||
needle == legacyID.lowercased() ||
needle == receiverID.lowercased() ||
needle == serviceName.lowercased() ||
needle == "service:\(serviceName)".lowercased() {
return true
}

let legacyServiceName = needle.split(separator: "|", maxSplits: 1).first.map(String.init) ?? ""
return !legacyServiceName.isEmpty && legacyServiceName == serviceName.lowercased()
}

var shortHostName: String? {
guard let host = hostName, !host.isEmpty else { return nil }
Expand Down Expand Up @@ -158,6 +187,7 @@ final class TBReceiverDiscovery: NSObject, ObservableObject {
}

let receiverName = stringValue("name").isEmpty ? service.name : stringValue("name")
let receiverID = stringValue("receiverID")
let receiverIP = stringValue("ip")
let thunderboltIP = stringValue("tbIP")
let usbIP = stringValue("usbIP")
Expand Down Expand Up @@ -194,6 +224,7 @@ final class TBReceiverDiscovery: NSObject, ObservableObject {
let receiver = TBDiscoveredReceiver(
serviceName: service.name,
receiverName: receiverName,
receiverID: receiverID,
preferredIP: preferredIP,
thunderboltIP: thunderboltIP,
usbIP: usbIP,
Expand All @@ -207,7 +238,12 @@ final class TBReceiverDiscovery: NSObject, ObservableObject {
hostName: service.hostName
)

if let index = receivers.firstIndex(where: { $0.serviceName == receiver.serviceName }) {
if let index = receivers.firstIndex(where: {
if !receiver.receiverID.isEmpty && !$0.receiverID.isEmpty {
return $0.receiverID == receiver.receiverID
}
return $0.serviceName == receiver.serviceName
}) {
receivers[index] = receiver
} else {
receivers.append(receiver)
Expand Down
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