Background execution (#100)

* #99 Implement background tasks * #99 Add changelog * #99 Fix some code smells * #99 Use background tasks in room timeline controller * #99 Move background task service into room proxy and media provider
2026-11-03 06:55:59 +00:00 · 2022-06-29 13:03:28 +03:00
parent d74158ced1
commit dbee1924eb
13 changed files with 619 additions and 9 deletions
@@ -0,0 +1,95 @@
+//
+//  UIKitBackgroundTask.swift
+//  ElementX
+//
+//  Created by Ismail on 28.06.2022.
+//  Copyright © 2022 Element. All rights reserved.
+//
+
+import Foundation
+import UIKit
+
+/// UIKitBackgroundTask is a concrete implementation of BackgroundTaskProtocol using UIApplication background task.
+class UIKitBackgroundTask: BackgroundTaskProtocol {
+    let name: String
+    var isRunning: Bool {
+        identifier != .invalid
+    }
+    let isReusable: Bool
+    let expirationHandler: BackgroundTaskExpirationHandler?
+    var elapsedTime: TimeInterval {
+        return Date().timeIntervalSince(startDate) * 1000
+    }
+
+    private let application: ApplicationProtocol
+    private var identifier: UIBackgroundTaskIdentifier = .invalid
+    private var useCounter: Int = 0
+    private let startDate: Date = Date()
+
+    /// Initializes and starts a new background task
+    /// - Parameters:
+    ///   - name: name
+    ///   - isReusable: flag indicating the task is reusable
+    ///   - application: application instance
+    ///   - expirationHandler: expiration handler
+    init?(name: String,
+          isReusable: Bool,
+          application: ApplicationProtocol,
+          expirationHandler: BackgroundTaskExpirationHandler?) {
+        self.name = name
+        self.isReusable = isReusable
+        self.application = application
+        self.expirationHandler = expirationHandler
+
+        // attempt to start
+        identifier = application.beginBackgroundTask(withName: name) { [weak self] in
+            guard let self = self else { return }
+            self.expirationHandler?(self)
+        }
+
+        if identifier == .invalid {
+            MXLog.debug("[UIKitBackgroundTask] Do not start background task: \(name), as OS declined")
+            //  call expiration handler immediately
+            expirationHandler?(self)
+            return nil
+        }
+
+        if isReusable {
+            //  creation itself is a use
+            reuse()
+        }
+
+        MXLog.debug("[UIKitBackgroundTask] Start background task #\(identifier.rawValue) - \(name)")
+    }
+
+    func reuse() {
+        guard isReusable else {
+            return
+        }
+        useCounter += 1
+    }
+
+    func stop() {
+        if isReusable {
+            useCounter -= 1
+            if useCounter <= 0 {
+                endTask()
+            }
+        } else {
+            endTask()
+        }
+    }
+
+    private func endTask() {
+        if identifier != .invalid {
+            MXLog.debug("[UIKitBackgroundTask] End background task #\(identifier.rawValue) - \(name) after \(readableElapsedTime)")
+
+            application.endBackgroundTask(identifier)
+            identifier = .invalid
+        }
+    }
+
+    private var readableElapsedTime: String {
+        String(format: "%.3fms", elapsedTime)
+    }
+}