LibCore: Add swift bindings for EventLoop as an Executor and Actor

Author: https://github.com/ADKaster
Commit: c8787e6a9f
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/3880

Libraries/LibCore/EventLoopExecutor.swift

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2025, Andrew Kaster <andrew@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+import AK
+@_exported import CoreCxx
+
+extension Core.EventLoop: Equatable {
+    func deferred_invoke(_ task: @escaping () -> Void) {
+        Core.deferred_invoke_block(self, task)
+    }
+
+    public static func == (lhs: Core.EventLoop, rhs: Core.EventLoop) -> Bool {
+        Unmanaged.passUnretained(lhs).toOpaque() == Unmanaged.passUnretained(rhs).toOpaque()
+    }
+}
+
+public class EventLoopExecutor: SerialExecutor, TaskExecutor, @unchecked Sendable {
+    nonisolated private let eventLoop: Core.EventLoop
+
+    public init() {
+        eventLoop = Core.EventLoop.current()
+    }
+
+    public init(eventLoop: Core.EventLoop) {
+        self.eventLoop = eventLoop
+    }
+
+    public nonisolated func enqueue(_ job: consuming ExecutorJob) {
+        let job = UnownedJob(job)
+        eventLoop.deferred_invoke { [self, job] in
+            job.runSynchronously(
+                isolatedTo: self.asUnownedSerialExecutor(),
+                taskExecutor: self.asUnownedTaskExecutor())
+        }
+    }
+
+    public func checkIsolated() {
+        precondition(Core.EventLoop.current() == eventLoop)
+    }
+}
+
+public protocol EventLoopActor: Actor {
+    nonisolated var executor: EventLoopExecutor { get }  // impl with a let
+}
+
+extension EventLoopActor {
+    public nonisolated var unownedExecutor: UnownedSerialExecutor {
+        executor.asUnownedSerialExecutor()
+    }
+}