Implement closed group logic changes

SessionMessagingKit/Database/Storage+ClosedGroups.swift

@@ -8,6 +8,8 @@ extension Storage {
     private static let closedGroupPublicKeyCollection = "SNClosedGroupPublicKeyCollection"
     
     private static let closedGroupFormationTimestampCollection = "SNClosedGroupFormationTimestampCollection"
+    
+    private static let closedGroupZombieMembersCollection = "SNClosedGroupZombieMembersCollection"
 
     public func getClosedGroupEncryptionKeyPairs(for groupPublicKey: String) -> [ECKeyPair] {
         let collection = Storage.getClosedGroupEncryptionKeyPairCollection(for: groupPublicKey)
@@ -35,6 +37,14 @@ extension Storage {
         let collection = Storage.getClosedGroupEncryptionKeyPairCollection(for: groupPublicKey)
         (transaction as! YapDatabaseReadWriteTransaction).removeAllObjects(inCollection: collection)
     }
+    
+    public func getUserClosedGroupPublicKeys() -> Set<String> {
+        var result: Set<String> = []
+        Storage.read { transaction in
+            result = Set(transaction.allKeys(inCollection: Storage.closedGroupPublicKeyCollection))
+        }
+        return result
+    }
 
     public func addClosedGroupPublicKey(_ groupPublicKey: String, using transaction: Any) {
         (transaction as! YapDatabaseReadWriteTransaction).setObject(groupPublicKey, forKey: groupPublicKey, inCollection: Storage.closedGroupPublicKeyCollection)
@@ -55,14 +65,20 @@ extension Storage {
     public func setClosedGroupFormationTimestamp(to timestamp: UInt64, for groupPublicKey: String, using transaction: Any) {
         (transaction as! YapDatabaseReadWriteTransaction).setObject(timestamp, forKey: groupPublicKey, inCollection: Storage.closedGroupFormationTimestampCollection)
     }
-
-    public func getUserClosedGroupPublicKeys() -> Set<String> {
+    
+    public func getZombieMembers(for groupPublicKey: String) -> Set<String> {
         var result: Set<String> = []
         Storage.read { transaction in
-            result = result.union(Set(transaction.allKeys(inCollection: Storage.closedGroupPublicKeyCollection)))
+            if let zombies = transaction.object(forKey: groupPublicKey, inCollection: Storage.closedGroupZombieMembersCollection) as? Set<String> {
+                result = zombies
+            }
         }
         return result
     }
+    
+    public func setZombieMembers(for groupPublicKey: String, to zombies: Set<String>, using transaction: Any) {
+        (transaction as! YapDatabaseReadWriteTransaction).setObject(zombies, forKey: groupPublicKey, inCollection: Storage.closedGroupZombieMembersCollection)
+    }
 
     public func isClosedGroup(_ publicKey: String) -> Bool {
         getUserClosedGroupPublicKeys().contains(publicKey)

SessionMessagingKit/Sending & Receiving/MessageReceiver+Handling.swift

@@ -512,7 +512,8 @@ extension MessageReceiver {
         guard let groupPublicKey = message.groupPublicKey else { return }
         performIfValid(for: message, using: transaction) { groupID, thread, group in
             // Check that the admin wasn't removed
-            let members = Set(group.groupMemberIds).subtracting(membersAsData.map { $0.toHexString() })
+            let removedMembers = membersAsData.map { $0.toHexString() }
+            let members = Set(group.groupMemberIds).subtracting(removedMembers)
             guard members.contains(group.groupAdminIds.first!) else {
                 return SNLog("Ignoring invalid closed group update.")
             }
@@ -531,7 +532,9 @@ extension MessageReceiver {
                 Storage.shared.removeAllClosedGroupEncryptionKeyPairs(for: groupPublicKey, using: transaction)
                 let _ = PushNotificationAPI.performOperation(.unsubscribe, for: groupPublicKey, publicKey: userPublicKey)
             }
-            // TODO: Remove from zombie list
+            let storage = SNMessagingKitConfiguration.shared.storage
+            let zombies = storage.getZombieMembers(for: groupPublicKey).subtracting(removedMembers)
+            storage.setZombieMembers(for: groupPublicKey, to: zombies, using: transaction)
             // Update the group
             let newGroupModel = TSGroupModel(title: group.groupName, memberIds: [String](members), image: nil, groupId: groupID, groupType: .closedGroup, adminIds: group.groupAdminIds)
             thread.setGroupModel(newGroupModel, with: transaction)
@@ -561,7 +564,9 @@ extension MessageReceiver {
                 Storage.shared.removeClosedGroupPublicKey(groupPublicKey, using: transaction)
                 let _ = PushNotificationAPI.performOperation(.unsubscribe, for: groupPublicKey, publicKey: getUserHexEncodedPublicKey())
             } else {
-                // TODO: Mark as zombie
+                let storage = SNMessagingKitConfiguration.shared.storage
+                let zombies = storage.getZombieMembers(for: groupPublicKey).union([ message.sender! ])
+                storage.setZombieMembers(for: groupPublicKey, to: zombies, using: transaction)
             }
             // Update the group
             let newGroupModel = TSGroupModel(title: group.groupName, memberIds: [String](members), image: nil, groupId: groupID, groupType: .closedGroup, adminIds: group.groupAdminIds)

SessionMessagingKit/Sending & Receiving/MessageSender+ClosedGroups.swift

@@ -216,6 +216,10 @@ extension MessageSender {
             return Promise(error: Error.invalidClosedGroupUpdate)
         }
         let members = Set(group.groupMemberIds).subtracting(membersToRemove)
+        // Update zombie list
+        let storage = SNMessagingKitConfiguration.shared.storage
+        let zombies = storage.getZombieMembers(for: groupPublicKey).subtracting(membersToRemove)
+        storage.setZombieMembers(for: groupPublicKey, to: zombies, using: transaction)
         // Send the update to the group and generate + distribute a new encryption key pair
         let closedGroupControlMessage = ClosedGroupControlMessage(kind: .membersRemoved(members: membersToRemove.map { Data(hex: $0) }))
         let promise = MessageSender.sendNonDurably(closedGroupControlMessage, in: thread, using: transaction).map {

SessionMessagingKit/Storage.swift

@@ -22,6 +22,8 @@ public protocol SessionMessagingKitStorageProtocol {
     // MARK: - Closed Groups
 
     func getUserClosedGroupPublicKeys() -> Set<String>
+    func getZombieMembers(for groupPublicKey: String) -> Set<String>
+    func setZombieMembers(for groupPublicKey: String, to zombies: Set<String>, using transaction: Any)
     func isClosedGroup(_ publicKey: String) -> Bool
 
     // MARK: - Jobs