Fix message index ordering

submodules/Postbox/Sources/ChatListViewState.swift

@@ -242,11 +242,13 @@ private final class ChatListViewSpaceState {
             let allIndices = (lowerOrAtAnchorMessages + higherThanAnchorMessages).map { $0.entryIndex }
             let allEntityIds = (lowerOrAtAnchorMessages + higherThanAnchorMessages).map { $0.entityId }
             if Set(allIndices).count != allIndices.count {
+                var debugRepeatedIndices = Set<MutableChatListEntryIndex>()
                 var existingIndices = Set<MutableChatListEntryIndex>()
                 for i in (0 ..< lowerOrAtAnchorMessages.count).reversed() {
                     if !existingIndices.contains(lowerOrAtAnchorMessages[i].entryIndex) {
                         existingIndices.insert(lowerOrAtAnchorMessages[i].entryIndex)
                     } else {
+                        debugRepeatedIndices.insert(lowerOrAtAnchorMessages[i].entryIndex)
                         lowerOrAtAnchorMessages.remove(at: i)
                     }
                 }
@@ -254,10 +256,11 @@ private final class ChatListViewSpaceState {
                     if !existingIndices.contains(higherThanAnchorMessages[i].entryIndex) {
                         existingIndices.insert(higherThanAnchorMessages[i].entryIndex)
                     } else {
+                        debugRepeatedIndices.insert(higherThanAnchorMessages[i].entryIndex)
                         higherThanAnchorMessages.remove(at: i)
                     }
                 }
-                postboxLog("allIndices not unique: \(allIndices)")
+                postboxLog("allIndices not unique, repeated: \(debugRepeatedIndices)")
                 
                 assert(false)
                 //preconditionFailure()

submodules/Postbox/Sources/Message.swift

@@ -10,7 +10,7 @@ public struct MessageId: Hashable, Comparable, CustomStringConvertible, PostboxC
     
     public var description: String {
         get {
-            return "\(namespace)_\(id)"
+            return "\(peerId):\(namespace)_\(id)"
         }
     }
     
@@ -18,6 +18,9 @@ public struct MessageId: Hashable, Comparable, CustomStringConvertible, PostboxC
         self.peerId = peerId
         self.namespace = namespace
         self.id = id
+        if namespace == 0 && id == 0 {
+            assert(true)
+        }
     }
     
     public init(_ buffer: ReadBuffer) {
@@ -103,8 +106,11 @@ public struct MessageIndex: Comparable, Hashable {
     }
     
     public func predecessor() -> MessageIndex {
-        if self.id.id != 0 {
-            return MessageIndex(id: MessageId(peerId: self.id.peerId, namespace: self.id.namespace, id: self.id.id - 1), timestamp: self.timestamp)
+        let previousPeerId = self.id.peerId.predecessor
+        if previousPeerId != self.id.peerId {
+            return MessageIndex(id: MessageId(peerId: previousPeerId, namespace: self.id.namespace, id: self.id.id), timestamp: self.timestamp)
+        } else if self.id.id != 0 {
+            return MessageIndex(id: MessageId(peerId: self.id.peerId, namespace: self.id.namespace, id: self.id.id), timestamp: self.timestamp)
         } else if self.id.namespace != 0 {
             return MessageIndex(id: MessageId(peerId: self.id.peerId, namespace: self.id.namespace - 1, id: Int32.max - 1), timestamp: self.timestamp)
         } else if self.timestamp != 0 {
@@ -115,8 +121,13 @@ public struct MessageIndex: Comparable, Hashable {
     }
     
     public func successor() -> MessageIndex {
+        let nextPeerId = self.id.peerId.successor
+        if nextPeerId != self.id.peerId {
+            return MessageIndex(id: MessageId(peerId: nextPeerId, namespace: self.id.namespace, id: self.id.id), timestamp: self.timestamp)
+        } else {
             return MessageIndex(id: MessageId(peerId: self.id.peerId, namespace: self.id.namespace, id: self.id.id == Int32.max ? self.id.id : (self.id.id + 1)), timestamp: self.timestamp)
         }
+    }
     
     public static func absoluteUpperBound() -> MessageIndex {
         return MessageIndex(id: MessageId(peerId: PeerId.max, namespace: Int32(Int8.max), id: Int32.max), timestamp: Int32.max)

submodules/Postbox/Sources/Peer.swift

@@ -8,6 +8,22 @@ public struct PeerId: Hashable, CustomStringConvertible, Comparable, Codable {
 
         fileprivate var rawValue: UInt32
 
+        var predecessor: Namespace {
+            if self.rawValue != 0 {
+                return Namespace(rawValue: self.rawValue - 1)
+            } else {
+                return self
+            }
+        }
+
+        var successor: Namespace {
+            if self.rawValue != Namespace.max.rawValue {
+                return Namespace(rawValue: self.rawValue + 1)
+            } else {
+                return self
+            }
+        }
+
         fileprivate init(rawValue: UInt32) {
             precondition((rawValue | 0x7) == 0x7)
 
@@ -28,12 +44,32 @@ public struct PeerId: Hashable, CustomStringConvertible, Comparable, Codable {
     }
 
     public struct Id: Comparable, Hashable, Codable {
+        public static var min: Id {
+            return Id(rawValue: 0)
+        }
+
         public static var max: Id {
             return Id(rawValue: 0x000000007fffffff)
         }
 
         fileprivate var rawValue: UInt64
 
+        var predecessor: Id {
+            if self.rawValue != 0 {
+                return Id(rawValue: self.rawValue - 1)
+            } else {
+                return self
+            }
+        }
+
+        var successor: Id {
+            if self.rawValue != Id.max.rawValue {
+                return Id(rawValue: self.rawValue + 1)
+            } else {
+                return self
+            }
+        }
+
         fileprivate init(rawValue: UInt64) {
             precondition((rawValue | 0x000FFFFFFFFFFFFF) == 0x000FFFFFFFFFFFFF)
 
@@ -60,6 +96,34 @@ public struct PeerId: Hashable, CustomStringConvertible, Comparable, Codable {
     public let namespace: Namespace
     public let id: Id
 
+    var predecessor: PeerId {
+        let previousId = self.id.predecessor
+        if previousId != self.id {
+            return PeerId(namespace: self.namespace, id: previousId)
+        } else {
+            let previousNamespace = self.namespace.predecessor
+            if previousNamespace != self.namespace {
+                return PeerId(namespace: previousNamespace, id: .max)
+            } else {
+                return self
+            }
+        }
+    }
+
+    var successor: PeerId {
+        let nextId = self.id.successor
+        if nextId != self.id {
+            return PeerId(namespace: self.namespace, id: nextId)
+        } else {
+            let nextNamespace = self.namespace.successor
+            if nextNamespace != self.namespace {
+                return PeerId(namespace: nextNamespace, id: .min)
+            } else {
+                return self
+            }
+        }
+    }
+    
     public init(namespace: Namespace, id: Id) {
         self.namespace = namespace
         self.id = id