84 lines
3.3 KiB
Swift
84 lines
3.3 KiB
Swift
import PromiseKit
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@objc(LKPoller)
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public final class LokiPoller : NSObject {
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private let onMessagesReceived: ([SSKProtoEnvelope]) -> Void
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private let storage = OWSPrimaryStorage.shared()
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private var hasStarted = false
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private var hasStopped = false
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private var usedSnodes = Set<LokiAPITarget>()
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// MARK: Settings
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private static let retryInterval: TimeInterval = 4
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// MARK: Initialization
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@objc public init(onMessagesReceived: @escaping ([SSKProtoEnvelope]) -> Void) {
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self.onMessagesReceived = onMessagesReceived
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super.init()
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}
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// MARK: Public API
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@objc public func startIfNeeded() {
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guard !hasStarted else { return }
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print("[Loki] Started polling.")
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hasStarted = true
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hasStopped = false
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setUpPolling()
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}
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@objc public func stopIfNeeded() {
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guard !hasStopped else { return }
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print("[Loki] Stopped polling.")
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hasStarted = false
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hasStopped = true
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usedSnodes.removeAll()
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}
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// MARK: Private API
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private func setUpPolling() {
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guard !hasStopped else { return }
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LokiAPI.getSwarm(for: getUserHexEncodedPublicKey()).then { [weak self] _ -> Promise<Void> in
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guard let strongSelf = self else { return Promise { $0.fulfill(()) } }
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strongSelf.usedSnodes.removeAll()
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let (promise, seal) = Promise<Void>.pending()
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strongSelf.pollNextSnode(seal: seal)
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return promise
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}.ensure { [weak self] in
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guard let strongSelf = self, !strongSelf.hasStopped else { return }
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Timer.scheduledTimer(withTimeInterval: LokiPoller.retryInterval, repeats: false) { _ in
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guard let strongSelf = self else { return }
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strongSelf.setUpPolling()
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}
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}
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}
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private func pollNextSnode(seal: Resolver<Void>) {
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let userHexEncodedPublicKey = getUserHexEncodedPublicKey()
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let swarm = LokiAPI.swarmCache[userHexEncodedPublicKey] ?? []
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let unusedSnodes = Set(swarm).subtracting(usedSnodes)
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if !unusedSnodes.isEmpty {
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// randomElement() uses the system's default random generator, which is cryptographically secure
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let nextSnode = unusedSnodes.randomElement()!
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usedSnodes.insert(nextSnode)
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poll(nextSnode, seal: seal).done(on: DispatchQueue.global()) {
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seal.fulfill(())
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}.catch(on: LokiAPI.errorHandlingQueue) { [weak self] error in
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print("[Loki] Polling \(nextSnode) failed; dropping it and switching to next snode.")
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LokiAPI.dropIfNeeded(nextSnode, hexEncodedPublicKey: userHexEncodedPublicKey)
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self?.pollNextSnode(seal: seal)
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}
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} else {
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seal.fulfill(())
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}
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}
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private func poll(_ target: LokiAPITarget, seal longTermSeal: Resolver<Void>) -> Promise<Void> {
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return LokiAPI.getRawMessages(from: target, usingLongPolling: false).then(on: DispatchQueue.global()) { [weak self] rawResponse -> Promise<Void> in
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guard let strongSelf = self, !strongSelf.hasStopped else { return Promise { $0.fulfill(()) } }
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let messages = LokiAPI.parseRawMessagesResponse(rawResponse, from: target)
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strongSelf.onMessagesReceived(messages)
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return strongSelf.poll(target, seal: longTermSeal)
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}
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}
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}
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