Signal-iOS/SignalServiceKit/Util/DeviceSleepManager.swift
2024-04-03 12:12:19 -05:00

95 lines
2.8 KiB
Swift

//
// Copyright 2017 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only
//
import Foundation
import SignalCoreKit
// This entity has responsibility for blocking the device from sleeping if
// certain behaviors (e.g. recording or playing voice messages) are in progress.
//
// Sleep blocking is keyed using "block objects" whose lifetime corresponds to
// the duration of the block. For example, sleep blocking during audio playback
// can be keyed to the audio player. This provides a measure of robustness.
// On the one hand, we can use weak references to track block objects and stop
// blocking if the block object is deallocated even if removeBlock() is not
// called. On the other hand, we will also get correct behavior to addBlock()
// being called twice with the same block object.
public class DeviceSleepManager: Dependencies {
public static let shared = DeviceSleepManager()
let serialQueue = DispatchQueue(label: "org.signal.device-sleep")
private class SleepBlock: CustomDebugStringConvertible {
weak var blockObject: AnyObject?
var debugDescription: String {
return "SleepBlock(\(String(reflecting: blockObject)))"
}
init(blockObject: AnyObject) {
self.blockObject = blockObject
}
}
private var blocks: [SleepBlock] = []
private init() {
SwiftSingletons.register(self)
NotificationCenter.default.addObserver(
self,
selector: #selector(didEnterBackground),
name: .OWSApplicationDidEnterBackground,
object: nil
)
}
@objc
private func didEnterBackground() {
AssertIsOnMainThread()
serialQueue.sync {
ensureSleepBlocking()
}
}
public func addBlock(blockObject: AnyObject) {
serialQueue.sync {
blocks.append(SleepBlock(blockObject: blockObject))
ensureSleepBlocking()
}
}
public func removeBlock(blockObject: AnyObject) {
serialQueue.sync {
blocks.removeAll(where: { $0.blockObject === blockObject })
ensureSleepBlocking()
}
}
private func ensureSleepBlocking() {
assertOnQueue(serialQueue)
// Cull expired blocks.
blocks.removeAll(where: { $0.blockObject === nil })
let shouldBlock = !blocks.isEmpty
let description: String
switch blocks.count {
case 0:
description = "no blocking objects"
case 1:
description = "\(blocks[0])"
default:
description = "\(blocks[0]) and \(blocks.count - 1) others"
}
DispatchQueue.main.async {
CurrentAppContext().ensureSleepBlocking(shouldBlock, blockingObjectsDescription: description)
}
}
}