Added method to retrieve legacy access challenge data

Postbox/MetadataTable.swift

@@ -5,6 +5,7 @@ private enum MetadataKey: Int32 {
     case State = 2
     case TransactionStateVersion = 3
     case MasterClientId = 4
+    case AccessChallenge = 5
     case RemoteContactCount = 6
 }
 
@@ -106,6 +107,17 @@ final class MetadataTable: Table {
         self.valueBox.set(self.table, key: self.key(.MasterClientId), value: buffer)
     }
     
+    func accessChallengeData() -> PostboxAccessChallengeData {
+        let encoder = PostboxEncoder()
+        PostboxAccessChallengeData.numericalPassword(value: "1111", timeout: nil, attempts: nil).encode(encoder)
+        self.valueBox.set(self.table, key: self.key(.AccessChallenge), value: encoder.makeReadBufferAndReset())
+        if let value = self.valueBox.get(self.table, key: self.key(.AccessChallenge)) {
+            return PostboxAccessChallengeData(decoder: PostboxDecoder(buffer: value))
+        } else {
+            return .none
+        }
+    }
+    
     func setRemoteContactCount(_ count: Int32) {
         self.cachedRemoteContactCount = count
         var mutableCount: Int32 = count

Postbox/Postbox.swift

@@ -769,6 +769,15 @@ public final class Transaction {
         }
     }
     
+    public func legacyGetAccessChallengeData() -> PostboxAccessChallengeData {
+        assert(!self.disposed)
+        if let postbox = self.postbox {
+            return postbox.metadataTable.accessChallengeData()
+        } else {
+            return .none
+        }
+    }
+    
     public func enumerateMedia(lowerBound: MessageIndex?, limit: Int) -> ([PeerId: Set<MediaId>], [MediaId: Media], MessageIndex?) {
         assert(!self.disposed)
         if let postbox = self.postbox {