Persist onion request paths to database

Signal/src/Loki/Components/PathStatusView.swift

@@ -16,6 +16,12 @@ final class PathStatusView : UIView {
     private func setUpViewHierarchy() {
         layer.cornerRadius = Values.pathStatusViewSize / 2
         layer.masksToBounds = false
+        if OnionRequestAPI.paths.count < OnionRequestAPI.pathCount {
+            let storage = OWSPrimaryStorage.shared()
+            storage.dbReadConnection.read { transaction in
+                OnionRequestAPI.paths = storage.getOnionRequestPaths(in: transaction)
+            }
+        }
         let color = (OnionRequestAPI.paths.count >= OnionRequestAPI.pathCount) ? Colors.accent : Colors.pathsBuilding
         setColor(to: color, isAnimated: false)
     }

SignalServiceKit/src/Loki/API/Onion Requests/OnionRequestAPI.swift

@@ -123,7 +123,13 @@ public enum OnionRequestAPI {
                 }
             }.map(on: LokiAPI.workQueue) { paths in
                 OnionRequestAPI.paths = paths
+                // Dispatch async on the main queue to avoid nested write transactions
                 DispatchQueue.main.async {
+                    let storage = OWSPrimaryStorage.shared()
+                    storage.dbReadWriteConnection.readWrite { transaction in
+                        print("[Loki] Persisting onion request paths to database.")
+                        storage.setOnionRequestPaths(paths, in: transaction)
+                    }
                     NotificationCenter.default.post(name: .pathsBuilt, object: nil)
                 }
                 return paths
@@ -136,6 +142,12 @@ public enum OnionRequestAPI {
     /// - Note: Exposed for testing purposes.
     internal static func getPath(excluding snode: LokiAPITarget) -> Promise<Path> {
         guard pathSize >= 1 else { preconditionFailure("Can't build path of size zero.") }
+        if paths.count < pathCount {
+            let storage = OWSPrimaryStorage.shared()
+            storage.dbReadConnection.read { transaction in
+                paths = storage.getOnionRequestPaths(in: transaction)
+            }
+        }
         // randomElement() uses the system's default random generator, which is cryptographically secure
         if paths.count >= pathCount {
             return Promise<Path> { seal in
@@ -148,8 +160,15 @@ public enum OnionRequestAPI {
         }
     }
 
-    private static func dropPath(containing snode: LokiAPITarget) {
+    private static func dropPaths() {
-        paths = paths.filter { !$0.contains(snode) }
+        paths.removeAll()
+        // Dispatch async on the main queue to avoid nested write transactions
+        DispatchQueue.main.async {
+            let storage = OWSPrimaryStorage.shared()
+            storage.dbReadWriteConnection.readWrite { transaction in
+                storage.clearOnionRequestPaths(in: transaction)
+            }
+        }
     }
 
     private static func dropGuardSnode(_ snode: LokiAPITarget) {
@@ -231,7 +250,7 @@ public enum OnionRequestAPI {
         }
         promise.catch(on: LokiAPI.workQueue) { error in // Must be invoked on LokiAPI.workQueue
             guard case HTTP.Error.httpRequestFailed(_, _) = error else { return }
-            dropPath(containing: guardSnode) // A snode in the path is bad; retry with a different path
+            dropPaths() // A snode in the path is bad; retry with a different path
             dropGuardSnode(guardSnode)
         }
         promise.handlingErrorsIfNeeded(forTargetSnode: snode, associatedWith: hexEncodedPublicKey)
@@ -262,7 +281,7 @@ private extension Promise where T == JSON {
                     DispatchQueue.main.async {
                         let storage = OWSPrimaryStorage.shared()
                         storage.dbReadWriteConnection.readWrite { transaction in
-                            storage.clearSnodePool(in: transaction)
+                            storage.dropSnode(snode, in: transaction)
                         }
                     }
                     LokiAPI.failureCount[snode] = 0

SignalServiceKit/src/Loki/Database/OWSPrimaryStorage+Loki.swift

@@ -30,6 +30,42 @@ public extension OWSPrimaryStorage {
 
 
 
+    // MARK: - Onion Request Path
+    private static let onionRequestPathCollection = "LokiOnionRequestPathCollection"
+
+    public func setOnionRequestPaths(_ paths: [OnionRequestAPI.Path], in transaction: YapDatabaseReadWriteTransaction) {
+        // FIXME: This is a bit of a dirty approach that assumes 2 paths of length 3 each. We should do better than this.
+        guard paths.count == 2 else { return }
+        let path0 = paths[0]
+        let path1 = paths[1]
+        guard path0.count == 3, path1.count == 3 else { return }
+        let collection = OWSPrimaryStorage.onionRequestPathCollection
+        transaction.setObject(path0[0], forKey: "0-0", inCollection: collection)
+        transaction.setObject(path0[1], forKey: "0-1", inCollection: collection)
+        transaction.setObject(path0[2], forKey: "0-2", inCollection: collection)
+        transaction.setObject(path1[0], forKey: "1-0", inCollection: collection)
+        transaction.setObject(path1[1], forKey: "1-1", inCollection: collection)
+        transaction.setObject(path1[2], forKey: "1-2", inCollection: collection)
+    }
+
+    public func getOnionRequestPaths(in transaction: YapDatabaseReadTransaction) -> [OnionRequestAPI.Path] {
+        let collection = OWSPrimaryStorage.onionRequestPathCollection
+        guard
+            let path0Snode0 = transaction.object(forKey: "0-0", inCollection: collection) as? LokiAPITarget,
+            let path0Snode1 = transaction.object(forKey: "0-1", inCollection: collection) as? LokiAPITarget,
+            let path0Snode2 = transaction.object(forKey: "0-2", inCollection: collection) as? LokiAPITarget,
+            let path1Snode0 = transaction.object(forKey: "1-0", inCollection: collection) as? LokiAPITarget,
+            let path1Snode1 = transaction.object(forKey: "1-1", inCollection: collection) as? LokiAPITarget,
+            let path1Snode2 = transaction.object(forKey: "1-2", inCollection: collection) as? LokiAPITarget else { return [] }
+        return [ [ path0Snode0, path0Snode1, path0Snode2 ], [ path1Snode0, path1Snode1, path1Snode2 ] ]
+    }
+
+    public func clearOnionRequestPaths(in transaction: YapDatabaseReadWriteTransaction) {
+        transaction.removeAllObjects(inCollection: OWSPrimaryStorage.onionRequestPathCollection)
+    }
+
+
+
     // MARK: - Session Requests
     private static let sessionRequestTimestampCollection = "LokiSessionRequestTimestampCollection"