ios, core: better notifications processing to avoid contention for database (#3485)

* core: forward notifications about message processing (for iOS notifications) * simplexmq * the option to keep database key, to allow re-opening the database * export new init with keepKey and reopen DB api * stop remote ctrl when suspending chat * ios: close/re-open db on suspend/activate * allow activating chat without restoring (for NSE) * update NSE to suspend/activate (does not work) * simplexmq * suspend chat and close database when last notification in the process is processed * stop reading notifications on message markers * replace async stream with cancellable concurrent queue * better synchronization of app and NSE * remove outside of task * remove unused var * whitespace * more debug logging, handle cancelled read after dequeue * comments * more comments
2024-12-17 17:20:21 +01:00 · 2023-12-09 21:59:40 +00:00
parent 2f7632a70f
commit d3059afc99
29 changed files with 661 additions and 224 deletions
@@ -0,0 +1,64 @@
+//
+//  ConcurrentQueue.swift
+//  SimpleX NSE
+//
+//  Created by Evgeny on 08/12/2023.
+//  Copyright © 2023 SimpleX Chat. All rights reserved.
+//
+
+import Foundation
+
+struct DequeueElement<T> {
+    var elementId: UUID?
+    var task: Task<T?, Never>
+}
+
+class ConcurrentQueue<T> {
+    private var queue: [T] = []
+    private var queueLock = DispatchQueue(label: "chat.simplex.app.SimpleX-NSE.concurrent-queue.lock.\(UUID())")
+    private var continuations = [(elementId: UUID, continuation: CheckedContinuation<T?, Never>)]()
+
+    func enqueue(_ el: T) {
+        resumeContinuation(el) { self.queue.append(el) }
+    }
+
+    func frontEnqueue(_ el: T) {
+        resumeContinuation(el) { self.queue.insert(el, at: 0) }
+    }
+
+    private func resumeContinuation(_ el: T, add: @escaping () -> Void) {
+        queueLock.sync {
+            if let (_, cont) = continuations.first {
+                continuations.remove(at: 0)
+                cont.resume(returning: el)
+            } else {
+                add()
+            }
+        }
+    }
+
+    func dequeue() -> DequeueElement<T> {
+        queueLock.sync {
+            if queue.isEmpty {
+                let elementId = UUID()
+                let task = Task {
+                    await withCheckedContinuation { cont in
+                        continuations.append((elementId, cont))
+                    }
+                }
+                return DequeueElement(elementId: elementId, task: task)
+            } else {
+                let el = queue.remove(at: 0)
+                return DequeueElement(task: Task { el })
+            }
+        }
+    }
+
+    func cancelDequeue(_ elementId: UUID) {
+        queueLock.sync {
+            let cancelled = continuations.filter { $0.elementId == elementId }
+            continuations.removeAll { $0.elementId == elementId }
+            cancelled.forEach { $0.continuation.resume(returning: nil) }
+        }
+    }
+}