Delete expired messages on startup

Author: golf1052

Signal-Windows.Lib/DisappearingMessagesManager.cs

@@ -4,6 +4,7 @@
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
+using libsignalservice.util;
 using Signal_Windows.Models;
 using Signal_Windows.Storage;
 using Windows.UI.Core;
@@ -35,9 +36,14 @@ public static void RemoveFrontend(CoreDispatcher coreDispatcher)
             }
         }
 
-        public static void AddMessage(SignalMessage message)
+        /// <summary>
+        /// Queues a message for deletion.
+        /// </summary>
+        /// <param name="message">The message to queue for deletion</param>
+        /// <remarks>If the message expire time is 0 then the message will not be deleted.</remarks>
+        public static void QueueForDeletion(SignalMessage message)
         {
-            if (message.ExpiresAt == 0)
+            if (message.ExpiresAt <= 0)
             {
                 return;
             }
@@ -61,6 +67,19 @@ public static void AddMessage(SignalMessage message)
             Task.Run(deleteTask);
         }
 
+        /// <summary>
+        /// Deletes expired messages from the database.
+        /// </summary>
+        public static void DeleteExpiredMessages()
+        {
+            long currentTimeMillis = Util.CurrentTimeMillis();
+            List<SignalMessage> expiredMessages = SignalDBContext.GetExpiredMessages(currentTimeMillis);
+            foreach (var expiredMessage in expiredMessages)
+            {
+                DeleteFromDb(expiredMessage);
+            }
+        }
+
         private static async Task DeleteMessage(SignalMessage message)
         {
             List<Task> operations = new List<Task>();
@@ -89,6 +108,11 @@ await dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
                 await t;
             }
 
+            DeleteFromDb(message);
+        }
+
+        private static void DeleteFromDb(SignalMessage message)
+        {
             foreach (var attachment in message.Attachments)
             {
                 SignalDBContext.DeleteAttachment(attachment);

Signal-Windows.Lib/IncomingMessages.cs

@@ -686,7 +686,7 @@ private async Task HandleSignalMessage(SignalServiceEnvelope envelope, SignalSer
                 // Make sure to update attachments count
                 message.AttachmentsCount = (uint)attachments.Count;
             }
-            DisappearingMessagesManager.AddMessage(message);
+            DisappearingMessagesManager.QueueForDeletion(message);
             await SignalLibHandle.Instance.SaveAndDispatchSignalMessage(message, conversation);
         }
     }

Signal-Windows.Lib/OutgoingMessages.cs

@@ -81,7 +81,7 @@ public async Task HandleOutgoingMessages()
                         {
                             await MessageSender.SendMessage(Token, new SignalServiceAddress(outgoingSignalMessage.ThreadId), message);
                             UpdateExpiresAt(outgoingSignalMessage);
-                            DisappearingMessagesManager.AddMessage(outgoingSignalMessage);
+                            DisappearingMessagesManager.QueueForDeletion(outgoingSignalMessage);
                             outgoingSignalMessage.Status = SignalMessageStatus.Confirmed;
                         }
                     }
@@ -105,7 +105,7 @@ public async Task HandleOutgoingMessages()
                         {
                             await SendMessage(recipients, message);
                             UpdateExpiresAt(outgoingSignalMessage);
-                            DisappearingMessagesManager.AddMessage(outgoingSignalMessage);
+                            DisappearingMessagesManager.QueueForDeletion(outgoingSignalMessage);
                             outgoingSignalMessage.Status = SignalMessageStatus.Confirmed;
                         }
                     }

Signal-Windows.Lib/Storage/DB.cs

@@ -919,6 +919,29 @@ public static SignalMessage IncreaseReceiptCountLocked(SignalServiceEnvelope env
             return set_mark? m : null;
         }
 
+        /// <summary>
+        /// Gets messages older than the given timestamp.
+        /// </summary>
+        /// <param name="timestamp">Timestamp in millis</param>
+        /// <returns>Expired messages</returns>
+        public static List<SignalMessage> GetExpiredMessages(long timestampMillis)
+        {
+            lock (DBLock)
+            {
+                using (var ctx = new SignalDBContext())
+                {
+                    var messages = ctx.Messages
+                        .Where(m => m.ExpiresAt > 0)
+                        .Where(m => m.ExpiresAt < timestampMillis)
+                        .Include(m => m.Attachments)
+                        .Include(m => m.Content)
+                        .AsNoTracking()
+                        .ToList();
+                    return messages;
+                }
+            }
+        }
+
         public static void DeleteMessage(SignalMessage message)
         {
             lock (DBLock)

Signal-Windows.RC/SignalBackgroundTask.cs

@@ -30,7 +30,6 @@ public sealed class SignalBackgroundTask : IBackgroundTask
 
         public void Run(IBackgroundTaskInstance taskInstance)
         {
-            
             Logger.LogInformation("Background task starting");
             Deferral = taskInstance.GetDeferral();
             SignalLogging.SetupLogging(false);

Signal-Windows/App.xaml.cs

@@ -75,6 +75,7 @@ public static SignalWindowsFrontend CurrentSignalWindowsFrontend(int id)
         private async void App_Resuming(object sender, object e)
         {
             Logger.LogInformation("Resuming");
+            DisappearingMessagesManager.DeleteExpiredMessages();
             await Handle.Reacquire();
         }
 
@@ -96,6 +97,7 @@ private void OnUnhandledException(object sender, UnhandledExceptionEventArgs ex)
         protected override async void OnActivated(IActivatedEventArgs args)
         {
             Logger.LogInformation("OnActivated() {0}", args.GetType());
+            DisappearingMessagesManager.DeleteExpiredMessages();
             if (args is ToastNotificationActivatedEventArgs toastArgs)
             {
                 string requestedConversation = toastArgs.Argument;
@@ -148,6 +150,7 @@ await Views[currentId].Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
         protected override async void OnLaunched(LaunchActivatedEventArgs e)
         {
             Logger.LogInformation("Launching (PreviousExecutionState={0})", e.PreviousExecutionState);
+            DisappearingMessagesManager.DeleteExpiredMessages();
             try
             {
                 string taskName = "SignalMessageBackgroundTask";