| 1 | import BackgroundTasks |
| 2 | import Foundation |
| 3 | import LChatCore |
| 4 | |
| 5 | // 🤖 Background App Refresh: iOS periodically wakes the app (cadence is the |
| 6 | // system's call — it learns from usage) and BackgroundSync pulls + decrypts + |
| 7 | // files new messages into the local store off the main thread. Together with |
| 8 | // the NSE's per-push ingest this keeps chats caught up before they're opened. |
| 9 | // |
| 10 | // The identifier must be listed in Info.plist's |
| 11 | // BGTaskSchedulerPermittedIdentifiers (project.yml), and registration must |
| 12 | // happen before didFinishLaunching returns (PushManager wires it). |
| 13 | enum BackgroundRefresh { |
| 14 | static var taskID: String { |
| 15 | (Bundle.main.bundleIdentifier ?? "com.elevenmessenger.messenger") + ".refresh" |
| 16 | } |
| 17 | |
| 18 | static func register() { |
| 19 | BGTaskScheduler.shared.register(forTaskWithIdentifier: taskID, using: nil) { task in |
| 20 | guard let refresh = task as? BGAppRefreshTask else { |
| 21 | task.setTaskCompleted(success: false) |
| 22 | return |
| 23 | } |
| 24 | handle(refresh) |
| 25 | } |
| 26 | } |
| 27 | |
| 28 | /// (Re)request the next wake. Cheap and idempotent — a duplicate submit |
| 29 | /// for a pending request just replaces it. Called when the app backgrounds |
| 30 | /// and from the handler itself, so the chain never breaks. |
| 31 | static func schedule() { |
| 32 | let req = BGAppRefreshTaskRequest(identifier: taskID) |
| 33 | req.earliestBeginDate = Date(timeIntervalSinceNow: 15 * 60) |
| 34 | try? BGTaskScheduler.shared.submit(req) |
| 35 | } |
| 36 | |
| 37 | private static func handle(_ task: BGAppRefreshTask) { |
| 38 | schedule() |
| 39 | // completed-once guard: the sync finishing and the expiration handler |
| 40 | // can race; BGTaskScheduler wants exactly one completion call. |
| 41 | let done = OneShot() |
| 42 | let work = Task { |
| 43 | // The app's background close gated the store (MessageStore.suspend); |
| 44 | // this pass is a legitimate write window, so open the bracket first. |
| 45 | await MessageStore.shared.resume() |
| 46 | await BackgroundSync.run(instances: InstancesStore.load()) |
| 47 | // Release the shared store's connection BEFORE declaring done — |
| 48 | // the process suspends any moment after, and a held app-group |
| 49 | // file lock at suspension is the 0xdead10cc kill. |
| 50 | await MessageStore.shared.suspend() |
| 51 | if done.claim() { task.setTaskCompleted(success: true) } |
| 52 | } |
| 53 | task.expirationHandler = { |
| 54 | work.cancel() |
| 55 | Task { |
| 56 | await MessageStore.shared.suspend() |
| 57 | if done.claim() { task.setTaskCompleted(success: false) } |
| 58 | } |
| 59 | } |
| 60 | } |
| 61 | |
| 62 | private final class OneShot: @unchecked Sendable { |
| 63 | private let lock = NSLock() |
| 64 | private var used = false |
| 65 | func claim() -> Bool { |
| 66 | lock.lock() |
| 67 | defer { lock.unlock() } |
| 68 | if used { return false } |
| 69 | used = true |
| 70 | return true |
| 71 | } |
| 72 | } |
| 73 | } |
| 74 | |
amadan