Persist swarm cache & make access modifiers explicit

Signal/src/AppDelegate.m

@@ -1204,6 +1204,8 @@ static NSTimeInterval launchStartedAt;
 {
     OWSAssertIsOnMainThread();
     OWSLogInfo(@"storageIsReady");
+    
+    [LokiAPI loadSwarmCache];
 
     [self checkIfAppIsReady];
 }

SignalServiceKit/src/Loki/API/LokiAPI+SwarmAPI.swift

@@ -1,6 +1,6 @@
 import PromiseKit
 
-extension LokiAPI {
+public extension LokiAPI {
     
     // MARK: Settings
     private static let minimumSnodeCount = 2
@@ -8,7 +8,26 @@ extension LokiAPI {
     private static let defaultSnodePort: UInt16 = 8080
     
     // MARK: Caching
-    fileprivate static var swarmCache: [String:[Target]] = [:] // TODO: Persist on disk
+    private static let swarmCacheKey = "swarmCacheKey"
+    private static let swarmCacheCollection = "swarmCacheCollection"
+    
+    fileprivate static var swarmCache: [String:[Target]] = [:]
+    
+    @objc public static func loadSwarmCache() {
+        var result: [String:[Target]]? = nil
+        storage.dbReadConnection.read { transaction in
+            let intermediate = transaction.object(forKey: swarmCacheKey, inCollection: swarmCacheCollection) as! [String:[TargetWrapper]]
+            result = intermediate.mapValues { $0.map { Target(from: $0) } }
+        }
+        swarmCache = result ?? [:]
+    }
+    
+    private static func saveSwarmCache() {
+        let intermediate = swarmCache.mapValues { $0.map { TargetWrapper(from: $0) } }
+        storage.dbReadWriteConnection.readWrite { transaction in
+            transaction.setObject(intermediate, forKey: swarmCacheKey, inCollection: swarmCacheCollection)
+        }
+    }
     
     // MARK: Internal API
     private static func getRandomSnode() -> Promise<Target> {
@@ -22,7 +41,10 @@ extension LokiAPI {
             return Promise<[Target]> { $0.fulfill(cachedSwarm) }
         } else {
             let parameters: [String:Any] = [ "pubKey" : hexEncodedPublicKey ]
-            return getRandomSnode().then { invoke(.getSwarm, on: $0, associatedWith: hexEncodedPublicKey, parameters: parameters) }.map { parseTargets(from: $0) }.get { swarmCache[hexEncodedPublicKey] = $0 }
+            return getRandomSnode().then { invoke(.getSwarm, on: $0, associatedWith: hexEncodedPublicKey, parameters: parameters) }.map { parseTargets(from: $0) }.get { swarm in
+                swarmCache[hexEncodedPublicKey] = swarm
+                saveSwarmCache()
+            }
         }
     }
     
@@ -46,9 +68,10 @@ extension LokiAPI {
     }
 }
 
+// MARK: Error Handling
 internal extension Promise {
     
-    func handlingSwarmSpecificErrorsIfNeeded(for target: LokiAPI.Target, associatedWith hexEncodedPublicKey: String) -> Promise<T> {
+    internal func handlingSwarmSpecificErrorsIfNeeded(for target: LokiAPI.Target, associatedWith hexEncodedPublicKey: String) -> Promise<T> {
         return recover { error -> Promise<T> in
             if let error = error as? NetworkManagerError {
                 switch error.statusCode {

SignalServiceKit/src/Loki/API/LokiAPI+Target.swift

@@ -0,0 +1,26 @@
+
+internal extension LokiAPI {
+    
+    internal struct Target : Hashable {
+        internal let address: String
+        internal let port: UInt16
+        
+        internal init(address: String, port: UInt16) {
+            self.address = address
+            self.port = port
+        }
+        
+        internal init(from targetWrapper: TargetWrapper) {
+            self.address = targetWrapper.address
+            self.port = targetWrapper.port
+        }
+        
+        internal enum Method : String {
+            /// Only supported by snode targets.
+            case getSwarm = "get_snodes_for_pubkey"
+            /// Only supported by snode targets.
+            case getMessages = "retrieve"
+            case sendMessage = "store"
+        }
+    }
+}

SignalServiceKit/src/Loki/API/LokiAPI+TargetWrapper.swift

@@ -0,0 +1,22 @@
+
+@objc internal final class TargetWrapper : NSObject, NSCoding {
+    internal let address: String
+    internal let port: UInt16
+    
+    internal init(from target: LokiAPI.Target) {
+        address = target.address
+        port = target.port
+        super.init()
+    }
+    
+    internal init?(coder: NSCoder) {
+        address = coder.decodeObject(forKey: "address") as! String
+        port = coder.decodeObject(forKey: "port") as! UInt16
+        super.init()
+    }
+    
+    internal func encode(with coder: NSCoder) {
+        coder.encode(address, forKey: "address")
+        coder.encode(port, forKey: "port")
+    }
+}

SignalServiceKit/src/Loki/API/LokiAPI.swift

@@ -1,26 +1,15 @@
 import PromiseKit
 
 @objc public final class LokiAPI : NSObject {
-    private static let storage = OWSPrimaryStorage.shared()
+    internal static let storage = OWSPrimaryStorage.shared()
     
     // MARK: Settings
     private static let version = "v1"
     public static let defaultMessageTTL: UInt64 = 1 * 24 * 60 * 60
+    private static let receivedMessageHashValuesKey = "receivedMessageHashValuesKey"
+    private static let receivedMessageHashValuesCollection = "receivedMessageHashValuesCollection"
     
     // MARK: Types
-    internal struct Target : Hashable {
-        let address: String
-        let port: UInt16
-        
-        enum Method : String {
-            /// Only supported by snode targets.
-            case getSwarm = "get_snodes_for_pubkey"
-            /// Only supported by snode targets.
-            case getMessages = "retrieve"
-            case sendMessage = "store"
-        }
-    }
-    
     public typealias RawResponse = Any
     
     public enum Error : LocalizedError {
@@ -149,21 +138,21 @@ import PromiseKit
     private static func getReceivedMessageHashValues() -> Set<String>? {
         var result: Set<String>? = nil
         storage.dbReadConnection.read { transaction in
-            result = storage.getReceivedMessageHashes(with: transaction)
+            result = transaction.object(forKey: receivedMessageHashValuesKey, inCollection: receivedMessageHashValuesCollection) as! Set<String>?
         }
         return result
     }
     
     private static func setReceivedMessageHashValues(to receivedMessageHashValues: Set<String>) {
         storage.dbReadWriteConnection.readWrite { transaction in
-            storage.setReceivedMessageHashes(receivedMessageHashValues, with: transaction)
+            transaction.setObject(receivedMessageHashValues, forKey: receivedMessageHashValuesKey, inCollection: receivedMessageHashValuesCollection)
         }
     }
 }
 
 private extension AnyPromise {
     
-    static func from<T : Any>(_ promise: Promise<T>) -> AnyPromise {
+    fileprivate static func from<T : Any>(_ promise: Promise<T>) -> AnyPromise {
         let result = AnyPromise(promise)
         result.retainUntilComplete()
         return result

SignalServiceKit/src/Loki/Crypto/ECKeyPair+Loki.swift

@@ -1,11 +1,11 @@
 
 public extension ECKeyPair {
     
-    @objc var hexEncodedPrivateKey: String {
+    @objc public var hexEncodedPrivateKey: String {
         return privateKey.map { String(format: "%02hhx", $0) }.joined()
     }
     
-    @objc var hexEncodedPublicKey: String {
+    @objc public var hexEncodedPublicKey: String {
         // Prefixing with "05" is necessary for what seems to be a sort of Signal public key versioning system
         // Ref: [NSData prependKeyType] in AxolotKit
         return "05" + publicKey.map { String(format: "%02hhx", $0) }.joined()

SignalServiceKit/src/Loki/Crypto/FallbackSessionCipher.swift

@@ -4,7 +4,7 @@ import Curve25519Kit
 private extension String {
 
     // Convert hex string to Data
-    var hexData: Data {
+    fileprivate var hexData: Data {
         var hex = self
         var data = Data()
         while(hex.count > 0) {

SignalServiceKit/src/Loki/Crypto/OWSPrimaryStorage+Loki.h

@@ -95,9 +95,6 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (void)setLastMessageHashForServiceNode:(NSString *)serviceNode hash:(NSString *)hash expiresAt:(u_int64_t)expiresAt transaction:(YapDatabaseReadWriteTransaction *)transaction NS_SWIFT_NAME(setLastMessageHash(forServiceNode:hash:expiresAt:transaction:));
 
-- (NSSet<NSString *> *_Nullable)getReceivedMessageHashesWithTransaction:(YapDatabaseReadTransaction *)transaction;
-- (void)setReceivedMessageHashes:(NSSet<NSString *> *)receivedMessageHashes withTransaction:(YapDatabaseReadWriteTransaction *)transaction;
-
 @end
 
 NS_ASSUME_NONNULL_END

SignalServiceKit/src/Loki/Crypto/OWSPrimaryStorage+Loki.m

@@ -153,12 +153,4 @@
     [transaction removeObjectForKey:serviceNode inCollection:LKLastMessageHashCollection];
 }
 
-- (NSSet<NSString *> *_Nullable)getReceivedMessageHashesWithTransaction:(YapDatabaseReadTransaction *)transaction {
-    return (NSSet *)[[transaction objectForKey:LKReceivedMessageHashesKey inCollection:LKReceivedMessageHashesCollection] as:NSSet.class];
-}
-
-- (void)setReceivedMessageHashes:(NSSet<NSString *> *)receivedMessageHashes withTransaction:(YapDatabaseReadWriteTransaction *)transaction {
-    [transaction setObject:receivedMessageHashes forKey:LKReceivedMessageHashesKey inCollection:LKReceivedMessageHashesCollection];
-}
-
 @end

SignalServiceKit/src/Loki/Crypto/ProofOfWork.swift

@@ -2,12 +2,12 @@ import CryptoSwift
 
 private extension UInt64 {
     
-    init(_ decimal: Decimal) {
+    fileprivate init(_ decimal: Decimal) {
         self.init(truncating: decimal as NSDecimalNumber)
     }
     
     // Convert a UInt8 array to a UInt64
-    init(_ bytes: [UInt8]) {
+    fileprivate init(_ bytes: [UInt8]) {
         precondition(bytes.count <= MemoryLayout<UInt64>.size)
         var value: UInt64 = 0
         for byte in bytes {
@@ -24,7 +24,7 @@ private extension MutableCollection where Element == UInt8, Index == Int {
     ///
     /// - Parameter amount: The amount to increment by
     /// - Returns: The incremented collection
-    func increment(by amount: Int) -> Self {
+    fileprivate func increment(by amount: Int) -> Self {
         var result = self
         var increment = amount
         for i in (0..<result.count).reversed() {

SignalServiceKit/src/Loki/Messages/FriendRequestExpirationJob.swift

@@ -156,7 +156,7 @@ public final class FriendRequestExpirationJob : NSObject {
 // MARK: Events
 private extension FriendRequestExpirationJob {
     
-    @objc func didBecomeActive() {
+    @objc fileprivate func didBecomeActive() {
         AssertIsOnMainThread()
         AppReadiness.runNowOrWhenAppDidBecomeReady {
             FriendRequestExpirationJob.serialQueue.async {
@@ -165,7 +165,7 @@ private extension FriendRequestExpirationJob {
         }
     }
     
-    @objc func willResignActive() {
+    @objc fileprivate func willResignActive() {
         AssertIsOnMainThread()
         resetNextExpireTimer()
     }
@@ -175,7 +175,7 @@ private extension FriendRequestExpirationJob {
 // MARK: Asserts
 private extension FriendRequestExpirationJob {
     
-    func AssertIsOnFriendRequestExpireQueue() {
+    fileprivate func AssertIsOnFriendRequestExpireQueue() {
         #if DEBUG
             guard #available(iOS 10.0, *) else { return }
             dispatchPrecondition(condition: .onQueue(FriendRequestExpirationJob.serialQueue))

SignalServiceKit/src/Loki/Utilities/Promise+Hashable.swift

@@ -1,6 +1,6 @@
 import PromiseKit
 
-extension Promise : Hashable {
+public extension Promise : Hashable {
     
     public func hash(into hasher: inout Hasher) {
         let reference = ObjectIdentifier(self).hashValue