feat(macOS): Replace UNIX sockets with XPC

AGENTS.md

@@ -69,6 +69,7 @@ The following details are important when working on the desktop client on macOS.
 - The PIMPL pattern is an established convention in the Objective-C++ source code files under `src/gui/macOS`.
 - To abstract macOS and Objective-C specific APIs, prefer to use Qt and C++ types in public identifiers declared in headers. Use and prefer Objective-C or native macOS features only internally in implementations. This rule applies only to the code in `src/gui/macOS`, though.
 - When writing code in Swift, respect strict concurrency rules and Swift 6 compatibility.
+- Manage memory explicitly and manually when writing or updating code located under `./src`. For example, do not use features like `__weak` from automatic reference counting in Objective-C because ARC is not used in this project.
 
 ### Tests
 

shell_integration/MacOSX/NextcloudIntegration/FileProviderExt/FileProviderExtension+CustomActions.swift

@@ -83,7 +83,7 @@ extension FileProviderExtension: NSFileProviderCustomAction {
                         }
                     }
 
-                    for try await result in group {
+                    for try await _ in group {
                         progress.completedUnitCount = 1
                     }
                 }

shell_integration/MacOSX/NextcloudIntegration/FileProviderExt/FileProviderExtension+NSXPCListenerDelegate.swift

@@ -29,6 +29,9 @@ extension FileProviderExtension: NSXPCListenerDelegate {
         if let appService = remoteObjectProxy as? AppProtocol {
             logger.info("Succeeded to cast remote object proxy, adopting it!")
             self.app = appService
+
+            // Initial status report as soon as the app service is available.
+            updatedSyncStateReporting(oldActions: Set<UUID>())
         } else {
             logger.error("Failed to cast remote object proxy to AppProtocol!")
             self.app = nil

shell_integration/MacOSX/NextcloudIntegration/FileProviderExt/FileProviderExtension.swift

@@ -2,7 +2,6 @@
 //  SPDX-License-Identifier: GPL-2.0-or-later
 
 import FileProvider
-import NCDesktopClientSocketKit
 import NextcloudKit
 import NextcloudFileProviderKit
 import OSLog
@@ -46,18 +45,6 @@ import OSLog
     var ignoredFiles: IgnoredFilesMatcher?
     lazy var ncKitBackground = NKBackground(nkCommonInstance: ncKit.nkCommonInstance)
 
-    lazy var socketClient: LocalSocketClient? = {
-        guard let containerUrl = FileManager.default.applicationGroupContainer() else {
-            logger.fault("Won't start socket client, no container URL available!")
-            return nil;
-        }
-
-        let socketPath = containerUrl.appendingPathComponent("fps", conformingTo: .archive)
-        let lineProcessor = FileProviderSocketLineProcessor(delegate: self, log: log)
-
-        return LocalSocketClient(socketPath: socketPath.path, lineProcessor: lineProcessor)
-    }()
-
     var syncActions = Set<UUID>()
     var errorActions = Set<UUID>()
     var actionsLock = NSLock()
@@ -101,7 +88,6 @@ import OSLog
         self.keychain = Keychain(log: log)
 
         super.init()
-        socketClient?.start()
     }
 
     func invalidate() {
@@ -548,13 +534,6 @@ import OSLog
         fpManager.signalEnumerator(for: .workingSet, completionHandler: completionHandler)
     }
 
-    @objc func sendFileProviderDomainIdentifier() {
-        let command = "FILE_PROVIDER_DOMAIN_IDENTIFIER_REQUEST_REPLY"
-        let argument = domain.identifier.rawValue
-        let message = command + ":" + argument + "\n"
-        socketClient?.sendMessage(message)
-    }
-
     private func signalEnumeratorAfterAccountSetup() {
         guard let fpManager = NSFileProviderManager(for: domain) else {
             logger.error("Could not get file provider manager for domain \(self.domain.displayName), cannot notify after account setup")

shell_integration/MacOSX/NextcloudIntegration/FinderSyncAppProtocol.h

@@ -0,0 +1,61 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef FinderSyncAppProtocol_h
+#define FinderSyncAppProtocol_h
+
+#import <Foundation/Foundation.h>
+
+/**
+ * @brief The main app APIs exposed through XPC.
+ *
+ * This protocol is implemented by the main Nextcloud app and allows the FinderSync
+ * extension to query file statuses, menu items, and execute commands via XPC.
+ */
+@protocol FinderSyncAppProtocol
+
+/**
+ * @brief Retrieve the sync status for a file.
+ * @param path The absolute path to the file.
+ * @param completionHandler Callback with status string (e.g., "SYNC", "OK", "ERROR") or error.
+ */
+- (void)retrieveFileStatusForPath:(NSString *)path
+                completionHandler:(void(^)(NSString *status, NSError *error))completionHandler;
+
+/**
+ * @brief Retrieve the sync status for a folder.
+ * @param path The absolute path to the folder.
+ * @param completionHandler Callback with status string (e.g., "SYNC", "OK", "ERROR") or error.
+ */
+- (void)retrieveFolderStatusForPath:(NSString *)path
+                  completionHandler:(void(^)(NSString *status, NSError *error))completionHandler;
+
+/**
+ * @brief Get localized strings for the FinderSync extension UI.
+ * @param completionHandler Callback with dictionary of string keys and localized values, or error.
+ */
+- (void)getLocalizedStringsWithCompletionHandler:(void(^)(NSDictionary<NSString *, NSString *> *strings, NSError *error))completionHandler;
+
+/**
+ * @brief Get context menu items for the given paths.
+ * @param paths Array of absolute paths for which to get menu items.
+ * @param completionHandler Callback with array of menu item dictionaries (command, flags, text) or error.
+ */
+- (void)getMenuItemsForPaths:(NSArray<NSString *> *)paths
+           completionHandler:(void(^)(NSArray<NSDictionary *> *menuItems, NSError *error))completionHandler;
+
+/**
+ * @brief Execute a menu command for the given paths.
+ * @param command The command identifier (e.g., "SHARE", "ACTIVITY").
+ * @param paths Array of absolute paths on which to execute the command.
+ * @param completionHandler Callback with error if execution failed, or nil on success.
+ */
+- (void)executeMenuCommand:(NSString *)command
+                  forPaths:(NSArray<NSString *> *)paths
+         completionHandler:(void(^)(NSError *error))completionHandler;
+
+@end
+
+#endif /* FinderSyncAppProtocol_h */

shell_integration/MacOSX/NextcloudIntegration/FinderSyncExt/FinderSync.h

@@ -4,16 +4,15 @@
  * SPDX-License-Identifier: GPL-2.0-or-later
  */
 
 #import <Cocoa/Cocoa.h>
 #import <FinderSync/FinderSync.h>
-#import <NCDesktopClientSocketKit/LocalSocketClient.h>
 
 #import "SyncClient.h"
-#import "FinderSyncSocketLineProcessor.h"
+
+@class FinderSyncXPCManager;
 
 @interface FinderSync : FIFinderSync <SyncClientDelegate>
 
-@property FinderSyncSocketLineProcessor *lineProcessor;
-@property LocalSocketClient *localSocketClient;
+@property FinderSyncXPCManager *xpcManager;
 
 @end

shell_integration/MacOSX/NextcloudIntegration/FinderSyncExt/FinderSync.m

@@ -5,6 +5,7 @@
  */
 
 #import "FinderSync.h"
+#import "FinderSyncXPCManager.h"
 
 @interface FinderSync()
 {
@@ -25,8 +26,6 @@ - (instancetype)init
     if (self) {
         FIFinderSyncController *syncController = [FIFinderSyncController defaultController];
         NSBundle *extBundle = [NSBundle bundleForClass:[self class]];
-        // This was added to the bundle's Info.plist to get it from the build system
-        NSString *socketApiPrefix = [extBundle objectForInfoDictionaryKey:@"SocketApiPrefix"];
 
         NSImage *ok = [extBundle imageForResource:@"ok.icns"];
         NSImage *ok_swm = [extBundle imageForResource:@"ok_swm.icns"];
@@ -45,23 +44,11 @@ - (instancetype)init
         [syncController setBadgeImage:warning label:@"Ignored" forBadgeIdentifier:@"IGNORE+SWM"];
         [syncController setBadgeImage:error label:@"Error" forBadgeIdentifier:@"ERROR+SWM"];
 
-        NSURL *container = [[NSFileManager defaultManager] containerURLForSecurityApplicationGroupIdentifier:socketApiPrefix];
-        NSURL *library = [container URLByAppendingPathComponent:@"Library" isDirectory:true];
-        NSURL *applicationSupport = [library URLByAppendingPathComponent:@"Application Support" isDirectory:true];
-        NSURL *socketPath = [applicationSupport URLByAppendingPathComponent:@"s" isDirectory:NO];
-
-        NSLog(@"Socket path: %@", socketPath.path);
-
-        if (socketPath.path) {
-            self.lineProcessor = [[FinderSyncSocketLineProcessor alloc] initWithDelegate:self];
-            self.localSocketClient = [[LocalSocketClient alloc] initWithSocketPath:socketPath.path
-                                                                     lineProcessor:self.lineProcessor];
-            [self.localSocketClient start];
-            [self.localSocketClient askOnSocket:@"" query:@"GET_STRINGS"];
-        } else {
-            NSLog(@"No socket path. Not initiating local socket client.");
-            self.localSocketClient = nil;
-        }
+        // Initialize XPC manager instead of socket client
+        NSLog(@"Initializing FinderSync XPC manager");
+        self.xpcManager = [[FinderSyncXPCManager alloc] initWithDelegate:self];
+        [self.xpcManager start];
+        [self.xpcManager askOnSocket:@"" query:@"GET_STRINGS"];
 
         _registeredDirectories = NSMutableSet.set;
         _strings = NSMutableDictionary.dictionary;
@@ -82,7 +69,7 @@ - (void)requestBadgeIdentifierForURL:(NSURL *)url
 	}
 
 	NSString* normalizedPath = [[url path] decomposedStringWithCanonicalMapping];
-	[self.localSocketClient askForIcon:normalizedPath isDirectory:isDir];
+	[self.xpcManager askForIcon:normalizedPath isDirectory:isDir];
 }
 
 #pragma mark - Menu and toolbar item support
@@ -110,10 +97,10 @@ - (void)waitForMenuToArrive
 
 - (NSMenu *)menuForMenuKind:(FIMenuKind)whichMenu
 {
-    if(![self.localSocketClient isConnected]) {
+    if(![self.xpcManager isConnected]) {
         return nil;
     }
-    
+
 	FIFinderSyncController *syncController = [FIFinderSyncController defaultController];
 	NSMutableSet *rootPaths = [[NSMutableSet alloc] init];
 	[syncController.directoryURLs enumerateObjectsUsingBlock: ^(id obj, BOOL *stop) {
@@ -133,9 +120,9 @@ - (NSMenu *)menuForMenuKind:(FIMenuKind)whichMenu
 	}];
 
 	NSString *paths = [self selectedPathsSeparatedByRecordSeparator];
-	[self.localSocketClient askOnSocket:paths query:@"GET_MENU_ITEMS"];
-    
-    // Since the LocalSocketClient communicates asynchronously. wait here until the menu
+	[self.xpcManager askOnSocket:paths query:@"GET_MENU_ITEMS"];
+
+    // Since the XPC communication is asynchronous, wait here until the menu
     // is delivered by another thread
     [self waitForMenuToArrive];
 
@@ -171,7 +158,7 @@ - (void)subMenuActionClicked:(id)sender {
 	long idx = [(NSMenuItem*)sender tag];
 	NSString *command = [[_menuItems objectAtIndex:idx] valueForKey:@"command"];
 	NSString *paths = [self selectedPathsSeparatedByRecordSeparator];
-	[self.localSocketClient askOnSocket:paths query:command];
+	[self.xpcManager askOnSocket:paths query:command];
 }
 
 #pragma mark - SyncClientProxyDelegate implementation