Add new VIEWED item in RecieptMessage enumeration.

Also includes necessary Database changes for supporting this as well as View-Once receipt support.

app/src/main/java/org/thoughtcrime/securesms/database/GroupReceiptDatabase.java

@@ -34,6 +34,7 @@ public class GroupReceiptDatabase extends Database {
   public static final int STATUS_UNDELIVERED = 0;
   public static final int STATUS_DELIVERED   = 1;
   public static final int STATUS_READ        = 2;
+  public static final int STATUS_VIEWED      = 3;
 
   public static final String CREATE_TABLE = "CREATE TABLE " + TABLE_NAME + " (" + ID + " INTEGER PRIMARY KEY, "                          +
       MMS_ID + " INTEGER, " + RECIPIENT_ID + " INTEGER, " + STATUS + " INTEGER, " + TIMESTAMP + " INTEGER, " + UNIDENTIFIED + " INTEGER DEFAULT 0);";

app/src/main/java/org/thoughtcrime/securesms/database/MessageDatabase.java

@@ -117,12 +117,14 @@ public abstract class MessageDatabase extends Database implements MmsSmsColumns
   public abstract void markDownloadState(long messageId, long state);
   public abstract void markIncomingNotificationReceived(long threadId);
 
-  public abstract boolean incrementReceiptCount(SyncMessageId messageId, long timestamp, boolean deliveryReceipt);
+  public abstract boolean incrementReceiptCount(SyncMessageId messageId, long timestamp, @NonNull ReceiptType receiptType);
   public abstract List<Pair<Long, Long>> setTimestampRead(SyncMessageId messageId, long proposedExpireStarted);
   public abstract List<MarkedMessageInfo> setEntireThreadRead(long threadId);
   public abstract List<MarkedMessageInfo> setMessagesReadSince(long threadId, long timestamp);
   public abstract List<MarkedMessageInfo> setAllMessagesRead();
   public abstract Pair<Long, Long> updateBundleMessageBody(long messageId, String body);
+  public abstract @NonNull List<MarkedMessageInfo> getViewedIncomingMessages(long threadId);
+  public abstract @Nullable MarkedMessageInfo setIncomingMessageViewed(long messageId);
 
   public abstract void addFailures(long messageId, List<NetworkFailure> failure);
   public abstract void removeFailure(long messageId, NetworkFailure failure);
@@ -555,6 +557,28 @@ public abstract class MessageDatabase extends Database implements MmsSmsColumns
     return -1;
   }
 
+  protected enum ReceiptType {
+    READ(READ_RECEIPT_COUNT, GroupReceiptDatabase.STATUS_READ),
+    DELIVERY(DELIVERY_RECEIPT_COUNT, GroupReceiptDatabase.STATUS_DELIVERED),
+    VIEWED(VIEWED_RECEIPT_COUNT, GroupReceiptDatabase.STATUS_VIEWED);
+
+    private final String columnName;
+    private final int    groupStatus;
+
+    ReceiptType(String columnName, int groupStatus) {
+      this.columnName  = columnName;
+      this.groupStatus = groupStatus;
+    }
+
+    public String getColumnName() {
+      return columnName;
+    }
+
+    public int getGroupStatus() {
+      return groupStatus;
+    }
+  }
+
   public static class SyncMessageId {
 
     private final RecipientId recipientId;

app/src/main/java/org/thoughtcrime/securesms/database/MmsDatabase.java

@@ -185,7 +185,8 @@ public class MmsDatabase extends MessageDatabase {
                                                                                   REACTIONS_LAST_SEEN    + " INTEGER DEFAULT -1, " +
                                                                                   REMOTE_DELETED         + " INTEGER DEFAULT 0, " +
                                                                                   MENTIONS_SELF          + " INTEGER DEFAULT 0, " +
-                                                                                  NOTIFIED_TIMESTAMP     + " INTEGER DEFAULT 0);";
+                                                                                  NOTIFIED_TIMESTAMP     + " INTEGER DEFAULT 0, " +
+                                                                                  VIEWED_RECEIPT_COUNT   + " INTEGER DEFAULT 0);";
 
   public static final String[] CREATE_INDEXS = {
     "CREATE INDEX IF NOT EXISTS mms_thread_id_index ON " + TABLE_NAME + " (" + THREAD_ID + ");",
@@ -210,7 +211,7 @@ public class MmsDatabase extends MessageDatabase {
       DELIVERY_RECEIPT_COUNT, READ_RECEIPT_COUNT, MISMATCHED_IDENTITIES, NETWORK_FAILURE, SUBSCRIPTION_ID,
       EXPIRES_IN, EXPIRE_STARTED, NOTIFIED, QUOTE_ID, QUOTE_AUTHOR, QUOTE_BODY, QUOTE_ATTACHMENT, QUOTE_MISSING, QUOTE_MENTIONS,
       SHARED_CONTACTS, LINK_PREVIEWS, UNIDENTIFIED, VIEW_ONCE, REACTIONS, REACTIONS_UNREAD, REACTIONS_LAST_SEEN,
-      REMOTE_DELETED, MENTIONS_SELF, NOTIFIED_TIMESTAMP,
+      REMOTE_DELETED, MENTIONS_SELF, NOTIFIED_TIMESTAMP, VIEWED_RECEIPT_COUNT,
       "json_group_array(json_object(" +
           "'" + AttachmentDatabase.ROW_ID + "', " + AttachmentDatabase.TABLE_NAME + "." + AttachmentDatabase.ROW_ID + ", " +
           "'" + AttachmentDatabase.UNIQUE_ID + "', " + AttachmentDatabase.TABLE_NAME + "." + AttachmentDatabase.UNIQUE_ID + ", " +
@@ -383,6 +384,69 @@ public class MmsDatabase extends MessageDatabase {
     throw new UnsupportedOperationException();
   }
 
+  @Override
+  public @NonNull List<MarkedMessageInfo> getViewedIncomingMessages(long threadId) {
+    SQLiteDatabase db      = databaseHelper.getReadableDatabase();
+    String[]       columns = new String[]{ID, RECIPIENT_ID, DATE_SENT, MESSAGE_BOX, THREAD_ID};
+    String         where   = THREAD_ID + " = ? AND " + VIEWED_RECEIPT_COUNT + " > 0 AND " + MESSAGE_BOX + " & " + Types.BASE_INBOX_TYPE + " = " + Types.BASE_INBOX_TYPE;
+    String[]       args    = SqlUtil.buildArgs(threadId);
+
+
+    try (Cursor cursor = db.query(getTableName(), columns, where, args, null, null, null, null)) {
+      if (cursor == null) {
+        return Collections.emptyList();
+      }
+
+      List<MarkedMessageInfo> results = new ArrayList<>(cursor.getCount());
+      while (cursor.moveToNext()) {
+        RecipientId    recipientId   = RecipientId.from(cursor.getLong(cursor.getColumnIndex(RECIPIENT_ID)));
+        long           dateSent      = cursor.getLong(cursor.getColumnIndex(DATE_SENT));
+        SyncMessageId  syncMessageId = new SyncMessageId(recipientId, dateSent);
+
+        results.add(new MarkedMessageInfo(threadId, syncMessageId, null));
+      }
+
+      return results;
+    }
+  }
+
+  @Override
+  public @Nullable MarkedMessageInfo setIncomingMessageViewed(long messageId) {
+    SQLiteDatabase database = databaseHelper.getWritableDatabase();
+    String[]       columns  = new String[]{ID, RECIPIENT_ID, DATE_SENT, MESSAGE_BOX, THREAD_ID};
+    String         where    = ID_WHERE + " AND " + VIEWED_RECEIPT_COUNT + " = 0";
+    String[]       args     = SqlUtil.buildArgs(messageId);
+
+    database.beginTransaction();
+    try (Cursor cursor = database.query(TABLE_NAME, columns, where, args, null, null, null)) {
+      if (cursor == null || !cursor.moveToFirst()) {
+        return null;
+      }
+
+      long type = CursorUtil.requireLong(cursor, MESSAGE_BOX);
+      if (Types.isSecureType(type) && Types.isInboxType(type)) {
+        long           threadId       = cursor.getLong(cursor.getColumnIndex(THREAD_ID));
+        RecipientId    recipientId    = RecipientId.from(cursor.getLong(cursor.getColumnIndex(RECIPIENT_ID)));
+        long           dateSent       = cursor.getLong(cursor.getColumnIndex(DATE_SENT));
+        SyncMessageId  syncMessageId  = new SyncMessageId(recipientId, dateSent);
+
+        MarkedMessageInfo result = new MarkedMessageInfo(threadId, syncMessageId, null);
+
+        ContentValues contentValues = new ContentValues();
+        contentValues.put(VIEWED_RECEIPT_COUNT, 1);
+
+        database.update(TABLE_NAME, contentValues, where, args);
+        database.setTransactionSuccessful();
+
+        return result;
+      } else {
+        return null;
+      }
+    } finally {
+      database.endTransaction();
+    }
+  }
+
   @Override
   public @NonNull Pair<Long, Long> insertReceivedCall(@NonNull RecipientId address, boolean isVideoOffer) {
     throw new UnsupportedOperationException();
@@ -540,23 +604,23 @@ public class MmsDatabase extends MessageDatabase {
   }
 
   @Override
-  public boolean incrementReceiptCount(SyncMessageId messageId, long timestamp, boolean deliveryReceipt) {
+  public boolean incrementReceiptCount(SyncMessageId messageId, long timestamp, @NonNull ReceiptType receiptType) {
     SQLiteDatabase database = databaseHelper.getWritableDatabase();
     boolean        found    = false;
 
-    try (Cursor cursor = database.query(TABLE_NAME, new String[] {ID, THREAD_ID, MESSAGE_BOX, RECIPIENT_ID, DELIVERY_RECEIPT_COUNT, READ_RECEIPT_COUNT},
+    try (Cursor cursor = database.query(TABLE_NAME, new String[] {ID, THREAD_ID, MESSAGE_BOX, RECIPIENT_ID, receiptType.getColumnName()},
                                         DATE_SENT + " = ?", new String[] {String.valueOf(messageId.getTimetamp())},
                                         null, null, null, null)) {
       while (cursor.moveToNext()) {
         if (Types.isOutgoingMessageType(cursor.getLong(cursor.getColumnIndexOrThrow(MESSAGE_BOX)))) {
           RecipientId theirRecipientId = RecipientId.from(cursor.getLong(cursor.getColumnIndexOrThrow(RECIPIENT_ID)));
           RecipientId ourRecipientId   = messageId.getRecipientId();
-          String      columnName       = deliveryReceipt ? DELIVERY_RECEIPT_COUNT : READ_RECEIPT_COUNT;
+          String      columnName       = receiptType.getColumnName();
 
           if (ourRecipientId.equals(theirRecipientId) || Recipient.resolved(theirRecipientId).isGroup()) {
             long    id               = cursor.getLong(cursor.getColumnIndexOrThrow(ID));
             long    threadId         = cursor.getLong(cursor.getColumnIndexOrThrow(THREAD_ID));
-            int     status           = deliveryReceipt ? GroupReceiptDatabase.STATUS_DELIVERED : GroupReceiptDatabase.STATUS_READ;
+            int     status           = receiptType.getGroupStatus();
             boolean isFirstIncrement = cursor.getLong(cursor.getColumnIndexOrThrow(columnName)) == 0;
 
             found = true;
@@ -577,7 +641,7 @@ public class MmsDatabase extends MessageDatabase {
         }
       }
 
-      if (!found && deliveryReceipt) {
+      if (!found && receiptType == ReceiptType.DELIVERY) {
         earlyDeliveryReceiptCache.increment(messageId.getTimetamp(), messageId.getRecipientId());
         return true;
       }
@@ -1808,6 +1872,7 @@ public class MmsDatabase extends MessageDatabase {
                                        Collections.emptyList(),
                                        false,
                                        false,
+                                       0,
                                        0);
     }
   }
@@ -1859,6 +1924,7 @@ public class MmsDatabase extends MessageDatabase {
       int       deliveryReceiptCount = cursor.getInt(cursor.getColumnIndexOrThrow(MmsDatabase.DELIVERY_RECEIPT_COUNT));
       int       readReceiptCount     = cursor.getInt(cursor.getColumnIndexOrThrow(MmsDatabase.READ_RECEIPT_COUNT));
       int       subscriptionId       = cursor.getInt(cursor.getColumnIndexOrThrow(MmsDatabase.SUBSCRIPTION_ID));
+      int       viewedReceiptCount   = cursor.getInt(cursor.getColumnIndexOrThrow(MmsSmsColumns.VIEWED_RECEIPT_COUNT));
 
       if (!TextSecurePreferences.isReadReceiptsEnabled(context)) {
         readReceiptCount = 0;
@@ -1880,7 +1946,7 @@ public class MmsDatabase extends MessageDatabase {
                                               addressDeviceId, dateSent, dateReceived, deliveryReceiptCount, threadId,
                                               contentLocationBytes, messageSize, expiry, status,
                                               transactionIdBytes, mailbox, subscriptionId, slideDeck,
-                                              readReceiptCount);
+                                              readReceiptCount, viewedReceiptCount);
     }
 
     private MediaMmsMessageRecord getMediaMmsMessageRecord(Cursor cursor) {
@@ -1907,9 +1973,11 @@ public class MmsDatabase extends MessageDatabase {
       List<ReactionRecord> reactions            = parseReactions(cursor);
       boolean              mentionsSelf         = CursorUtil.requireBoolean(cursor, MENTIONS_SELF);
       long                 notifiedTimestamp    = CursorUtil.requireLong(cursor, NOTIFIED_TIMESTAMP);
+      int                  viewedReceiptCount   = cursor.getInt(cursor.getColumnIndexOrThrow(MmsSmsColumns.VIEWED_RECEIPT_COUNT));
 
       if (!TextSecurePreferences.isReadReceiptsEnabled(context)) {
-        readReceiptCount = 0;
+        readReceiptCount   = 0;
+        viewedReceiptCount = 0;
       }
 
       Recipient                 recipient          = Recipient.live(RecipientId.from(recipientId)).get();
@@ -1928,7 +1996,7 @@ public class MmsDatabase extends MessageDatabase {
                                        threadId, body, slideDeck, partCount, box, mismatches,
                                        networkFailures, subscriptionId, expiresIn, expireStarted,
                                        isViewOnce, readReceiptCount, quote, contacts, previews, unidentified, reactions,
-                                       remoteDelete, mentionsSelf, notifiedTimestamp);
+                                       remoteDelete, mentionsSelf, notifiedTimestamp, viewedReceiptCount);
     }
 
     private List<IdentityKeyMismatch> getMismatchedIdentities(String document) {

app/src/main/java/org/thoughtcrime/securesms/database/MmsSmsColumns.java

@@ -14,6 +14,7 @@ public interface MmsSmsColumns {
   public static final String ADDRESS_DEVICE_ID        = "address_device_id";
   public static final String DELIVERY_RECEIPT_COUNT   = "delivery_receipt_count";
   public static final String READ_RECEIPT_COUNT       = "read_receipt_count";
+  public static final String VIEWED_RECEIPT_COUNT     = "viewed_receipt_count";
   public static final String MISMATCHED_IDENTITIES    = "mismatched_identities";
   public static final String UNIQUE_ROW_ID            = "unique_row_id";
   public static final String SUBSCRIPTION_ID          = "subscription_id";

app/src/main/java/org/thoughtcrime/securesms/database/MmsSmsDatabase.java

@@ -101,7 +101,8 @@ public class MmsSmsDatabase extends Database {
                                               MmsSmsColumns.REACTIONS_LAST_SEEN,
                                               MmsSmsColumns.REMOTE_DELETED,
                                               MmsDatabase.MENTIONS_SELF,
-                                              MmsSmsColumns.NOTIFIED_TIMESTAMP};
+                                              MmsSmsColumns.NOTIFIED_TIMESTAMP,
+                                              MmsSmsColumns.VIEWED_RECEIPT_COUNT};
 
   public MmsSmsDatabase(Context context, SQLCipherOpenHelper databaseHelper) {
     super(context, databaseHelper);
@@ -339,8 +340,8 @@ public class MmsSmsDatabase extends Database {
 
     db.beginTransaction();
     try {
-      DatabaseFactory.getSmsDatabase(context).incrementReceiptCount(syncMessageId, timestamp, true);
+      DatabaseFactory.getSmsDatabase(context).incrementReceiptCount(syncMessageId, timestamp, MessageDatabase.ReceiptType.DELIVERY);
-      DatabaseFactory.getMmsDatabase(context).incrementReceiptCount(syncMessageId, timestamp, true);
+      DatabaseFactory.getMmsDatabase(context).incrementReceiptCount(syncMessageId, timestamp, MessageDatabase.ReceiptType.DELIVERY);
       db.setTransactionSuccessful();
     } finally {
       db.endTransaction();
@@ -379,8 +380,8 @@ public class MmsSmsDatabase extends Database {
     try {
       boolean handled = false;
 
-      handled |= DatabaseFactory.getSmsDatabase(context).incrementReceiptCount(syncMessageId, timestamp, false);
+      handled |= DatabaseFactory.getSmsDatabase(context).incrementReceiptCount(syncMessageId, timestamp, MessageDatabase.ReceiptType.READ);
-      handled |= DatabaseFactory.getMmsDatabase(context).incrementReceiptCount(syncMessageId, timestamp, false);
+      handled |= DatabaseFactory.getMmsDatabase(context).incrementReceiptCount(syncMessageId, timestamp, MessageDatabase.ReceiptType.READ);
 
       db.setTransactionSuccessful();
 
@@ -390,6 +391,35 @@ public class MmsSmsDatabase extends Database {
     }
   }
 
+  /**
+   * @return A list of ID's that were not updated.
+   */
+  public @NonNull Collection<SyncMessageId> incrementViewedReceiptCounts(@NonNull List<SyncMessageId> syncMessageIds, long timestamp) {
+    SQLiteDatabase      db        = databaseHelper.getWritableDatabase();
+    List<SyncMessageId> unhandled = new LinkedList<>();
+
+    db.beginTransaction();
+    try {
+      for (SyncMessageId id : syncMessageIds) {
+        boolean handled = incrementViewedReceiptCount(id, timestamp);
+
+        if (!handled) {
+          unhandled.add(id);
+        }
+      }
+
+      db.setTransactionSuccessful();
+    } finally {
+      db.endTransaction();
+    }
+
+    return unhandled;
+  }
+
+  public boolean incrementViewedReceiptCount(SyncMessageId syncMessageId, long timestamp) {
+    return DatabaseFactory.getMmsDatabase(context).incrementReceiptCount(syncMessageId, timestamp, MessageDatabase.ReceiptType.VIEWED);
+  }
+
   public int getQuotedMessagePosition(long threadId, long quoteId, @NonNull RecipientId recipientId) {
     String order     = MmsSmsColumns.NORMALIZED_DATE_RECEIVED + " DESC";
     String selection = MmsSmsColumns.THREAD_ID + " = " + threadId + " AND " + MmsSmsColumns.REMOTE_DELETED + " = 0";
@@ -546,7 +576,8 @@ public class MmsSmsDatabase extends Database {
                               MmsSmsColumns.DATE_SERVER,
                               MmsSmsColumns.REMOTE_DELETED,
                               MmsDatabase.MENTIONS_SELF,
-                              MmsSmsColumns.NOTIFIED_TIMESTAMP };
+                              MmsSmsColumns.NOTIFIED_TIMESTAMP,
+                              MmsSmsColumns.VIEWED_RECEIPT_COUNT};
 
     String[] smsProjection = {SmsDatabase.DATE_SENT + " AS " + MmsSmsColumns.NORMALIZED_DATE_SENT,
                               SmsDatabase.DATE_RECEIVED + " AS " + MmsSmsColumns.NORMALIZED_DATE_RECEIVED,
@@ -581,7 +612,8 @@ public class MmsSmsDatabase extends Database {
                               MmsSmsColumns.DATE_SERVER,
                               MmsSmsColumns.REMOTE_DELETED,
                               MmsDatabase.MENTIONS_SELF,
-                              MmsSmsColumns.NOTIFIED_TIMESTAMP };
+                              MmsSmsColumns.NOTIFIED_TIMESTAMP,
+                              MmsSmsColumns.VIEWED_RECEIPT_COUNT};
 
     SQLiteQueryBuilder mmsQueryBuilder = new SQLiteQueryBuilder();
     SQLiteQueryBuilder smsQueryBuilder = new SQLiteQueryBuilder();
@@ -637,6 +669,7 @@ public class MmsSmsDatabase extends Database {
     mmsColumnsPresent.add(MmsDatabase.REMOTE_DELETED);
     mmsColumnsPresent.add(MmsDatabase.MENTIONS_SELF);
     mmsColumnsPresent.add(MmsSmsColumns.NOTIFIED_TIMESTAMP);
+    mmsColumnsPresent.add(MmsSmsColumns.VIEWED_RECEIPT_COUNT);
 
     Set<String> smsColumnsPresent = new HashSet<>();
     smsColumnsPresent.add(MmsSmsColumns.ID);

app/src/main/java/org/thoughtcrime/securesms/database/SmsDatabase.java

@@ -471,7 +471,11 @@ public class SmsDatabase extends MessageDatabase {
   }
 
   @Override
-  public boolean incrementReceiptCount(SyncMessageId messageId, long timestamp, boolean deliveryReceipt) {
+  public boolean incrementReceiptCount(SyncMessageId messageId, long timestamp, @NonNull ReceiptType receiptType) {
+    if (receiptType == ReceiptType.VIEWED) {
+      return false;
+    }
+
     SQLiteDatabase database     = databaseHelper.getWritableDatabase();
     boolean        foundMessage = false;
 
@@ -483,7 +487,7 @@ public class SmsDatabase extends MessageDatabase {
         if (Types.isOutgoingMessageType(cursor.getLong(cursor.getColumnIndexOrThrow(TYPE)))) {
           RecipientId theirRecipientId = messageId.getRecipientId();
           RecipientId outRecipientId   = RecipientId.from(cursor.getLong(cursor.getColumnIndexOrThrow(RECIPIENT_ID)));
-          String      columnName       = deliveryReceipt ? DELIVERY_RECEIPT_COUNT : READ_RECEIPT_COUNT;
+          String      columnName       = receiptType.getColumnName();
           boolean     isFirstIncrement = cursor.getLong(cursor.getColumnIndexOrThrow(columnName)) == 0;
 
           if (outRecipientId.equals(theirRecipientId)) {
@@ -507,7 +511,7 @@ public class SmsDatabase extends MessageDatabase {
         }
       }
 
-      if (!foundMessage && deliveryReceipt) {
+      if (!foundMessage && receiptType == ReceiptType.DELIVERY) {
         earlyDeliveryReceiptCache.increment(messageId.getTimetamp(), messageId.getRecipientId());
         return true;
       }
@@ -623,6 +627,16 @@ public class SmsDatabase extends MessageDatabase {
     return updateMessageBodyAndType(messageId, body, Types.TOTAL_MASK, type);
   }
 
+  @Override
+  public @NonNull List<MarkedMessageInfo> getViewedIncomingMessages(long threadId) {
+    return Collections.emptyList();
+  }
+
+  @Override
+  public @Nullable MarkedMessageInfo setIncomingMessageViewed(long messageId) {
+    return null;
+  }
+
   private Pair<Long, Long> updateMessageBodyAndType(long messageId, String body, long maskOff, long maskOn) {
     SQLiteDatabase db = databaseHelper.getWritableDatabase();
     db.execSQL("UPDATE " + TABLE_NAME + " SET " + BODY + " = ?, " +

app/src/main/java/org/thoughtcrime/securesms/database/helpers/SQLCipherOpenHelper.java

@@ -160,8 +160,9 @@ public class SQLCipherOpenHelper extends SQLiteOpenHelper {
   private static final int GV1_MIGRATION                    = 80;
   private static final int NOTIFIED_TIMESTAMP               = 81;
   private static final int GV1_MIGRATION_LAST_SEEN          = 82;
+  private static final int VIEWED_RECEIPTS                  = 83;
 
-  private static final int    DATABASE_VERSION = 82;
+  private static final int    DATABASE_VERSION = 83;
   private static final String DATABASE_NAME    = "signal.db";
 
   private final Context        context;
@@ -1170,6 +1171,10 @@ public class SQLCipherOpenHelper extends SQLiteOpenHelper {
         db.execSQL("ALTER TABLE recipient ADD COLUMN last_gv1_migrate_reminder INTEGER DEFAULT 0");
       }
 
+      if (oldVersion < VIEWED_RECEIPTS) {
+        db.execSQL("ALTER TABLE mms ADD COLUMN viewed_receipt_count INTEGER DEFAULT 0");
+      }
+
       db.setTransactionSuccessful();
     } finally {
       db.endTransaction();

app/src/main/java/org/thoughtcrime/securesms/database/model/DisplayRecord.java

@@ -45,10 +45,11 @@ public abstract class DisplayRecord {
   private final int        deliveryStatus;
   private final int        deliveryReceiptCount;
   private final int        readReceiptCount;
+  private final int        viewReceiptCount;
 
   DisplayRecord(String body, Recipient recipient, long dateSent,
                 long dateReceived, long threadId, int deliveryStatus, int deliveryReceiptCount,
-                long type, int readReceiptCount)
+                long type, int readReceiptCount, int viewReceiptCount)
   {
     this.threadId             = threadId;
     this.recipient            = recipient;
@@ -59,6 +60,7 @@ public abstract class DisplayRecord {
     this.deliveryReceiptCount = deliveryReceiptCount;
     this.readReceiptCount     = readReceiptCount;
     this.deliveryStatus       = deliveryStatus;
+    this.viewReceiptCount     = viewReceiptCount;
   }
 
   public @NonNull String getBody() {
@@ -188,6 +190,17 @@ public abstract class DisplayRecord {
     return readReceiptCount;
   }
 
+  /**
+   * For outgoing messages, this is incremented whenever a remote recipient has viewed our message
+   * and sends us a VIEWED receipt. For incoming messages, this is an indication of whether local
+   * user has viewed a piece of content.
+   *
+   * @return the number of times this has been viewed.
+   */
+  public int getViewedReceiptCount() {
+    return viewReceiptCount;
+  }
+
   public boolean isDelivered() {
     return (deliveryStatus >= SmsDatabase.Status.STATUS_COMPLETE &&
             deliveryStatus < SmsDatabase.Status.STATUS_PENDING) || deliveryReceiptCount > 0;

app/src/main/java/org/thoughtcrime/securesms/database/model/MediaMmsMessageRecord.java

@@ -74,12 +74,13 @@ public class MediaMmsMessageRecord extends MmsMessageRecord {
                                @NonNull List<ReactionRecord> reactions,
                                boolean remoteDelete,
                                boolean mentionsSelf,
-                               long notifiedTimestamp)
+                               long notifiedTimestamp,
+                               int viewedReceiptCount)
   {
     super(id, body, conversationRecipient, individualRecipient, recipientDeviceId, dateSent,
           dateReceived, dateServer, threadId, Status.STATUS_NONE, deliveryReceiptCount, mailbox, mismatches, failures,
           subscriptionId, expiresIn, expireStarted, viewOnce, slideDeck,
-          readReceiptCount, quote, contacts, linkPreviews, unidentified, reactions, remoteDelete, notifiedTimestamp);
+          readReceiptCount, quote, contacts, linkPreviews, unidentified, reactions, remoteDelete, notifiedTimestamp, viewedReceiptCount);
     this.partCount    = partCount;
     this.mentionsSelf = mentionsSelf;
   }

app/src/main/java/org/thoughtcrime/securesms/database/model/MessageRecord.java

@@ -93,10 +93,12 @@ public abstract class MessageRecord extends DisplayRecord {
                 List<NetworkFailure> networkFailures,
                 int subscriptionId, long expiresIn, long expireStarted,
                 int readReceiptCount, boolean unidentified,
-                @NonNull List<ReactionRecord> reactions, boolean remoteDelete, long notifiedTimestamp)
+                @NonNull List<ReactionRecord> reactions, boolean remoteDelete, long notifiedTimestamp,
+                int viewedReceiptCount)
   {
     super(body, conversationRecipient, dateSent, dateReceived,
-          threadId, deliveryStatus, deliveryReceiptCount, type, readReceiptCount);
+          threadId, deliveryStatus, deliveryReceiptCount, type,
+          readReceiptCount, viewedReceiptCount);
     this.id                  = id;
     this.individualRecipient = individualRecipient;
     this.recipientDeviceId   = recipientDeviceId;

app/src/main/java/org/thoughtcrime/securesms/database/model/MmsMessageRecord.java

@@ -33,9 +33,10 @@ public abstract class MmsMessageRecord extends MessageRecord {
                    @NonNull SlideDeck slideDeck, int readReceiptCount,
                    @Nullable Quote quote, @NonNull List<Contact> contacts,
                    @NonNull List<LinkPreview> linkPreviews, boolean unidentified,
-                   @NonNull List<ReactionRecord> reactions, boolean remoteDelete, long notifiedTimestamp)
+                   @NonNull List<ReactionRecord> reactions, boolean remoteDelete, long notifiedTimestamp,
+                   int viewedReceiptCount)
   {
-    super(id, body, conversationRecipient, individualRecipient, recipientDeviceId, dateSent, dateReceived, dateServer, threadId, deliveryStatus, deliveryReceiptCount, type, mismatches, networkFailures, subscriptionId, expiresIn, expireStarted, readReceiptCount, unidentified, reactions, remoteDelete, notifiedTimestamp);
+    super(id, body, conversationRecipient, individualRecipient, recipientDeviceId, dateSent, dateReceived, dateServer, threadId, deliveryStatus, deliveryReceiptCount, type, mismatches, networkFailures, subscriptionId, expiresIn, expireStarted, readReceiptCount, unidentified, reactions, remoteDelete, notifiedTimestamp, viewedReceiptCount);
 
     this.slideDeck = slideDeck;
     this.quote     = quote;

app/src/main/java/org/thoughtcrime/securesms/database/model/NotificationMmsMessageRecord.java

@@ -50,13 +50,14 @@ public class NotificationMmsMessageRecord extends MmsMessageRecord {
                                       long dateSent, long dateReceived, int deliveryReceiptCount,
                                       long threadId, byte[] contentLocation, long messageSize,
                                       long expiry, int status, byte[] transactionId, long mailbox,
-                                      int subscriptionId, SlideDeck slideDeck, int readReceiptCount)
+                                      int subscriptionId, SlideDeck slideDeck, int readReceiptCount,
+                                      int viewedReceiptCount)
   {
     super(id, "", conversationRecipient, individualRecipient, recipientDeviceId,
           dateSent, dateReceived, -1, threadId, Status.STATUS_NONE, deliveryReceiptCount, mailbox,
           new LinkedList<>(), new LinkedList<>(), subscriptionId,
           0, 0, false, slideDeck, readReceiptCount, null, Collections.emptyList(), Collections.emptyList(), false,
-          Collections.emptyList(), false, 0);
+          Collections.emptyList(), false, 0, viewedReceiptCount);
 
     this.contentLocation = contentLocation;
     this.messageSize     = messageSize;

app/src/main/java/org/thoughtcrime/securesms/database/model/SmsMessageRecord.java

@@ -55,7 +55,7 @@ public class SmsMessageRecord extends MessageRecord {
     super(id, body, recipient, individualRecipient, recipientDeviceId,
           dateSent, dateReceived, dateServer, threadId, status, deliveryReceiptCount, type,
           mismatches, new LinkedList<>(), subscriptionId,
-          expiresIn, expireStarted, readReceiptCount, unidentified, reactions, remoteDelete, notifiedTimestamp);
+          expiresIn, expireStarted, readReceiptCount, unidentified, reactions, remoteDelete, notifiedTimestamp, 0);
   }
 
   public long getType() {

app/src/main/java/org/thoughtcrime/securesms/jobmanager/Data.java

@@ -8,9 +8,11 @@ import com.fasterxml.jackson.annotation.JsonProperty;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 
 public class Data {
 
@@ -138,6 +140,19 @@ public class Data {
     return longArrays.get(key);
   }
 
+  public List<Long> getLongArrayAsList(@NonNull String key) {
+    throwIfAbsent(longArrays, key);
+
+    long[]     array = Objects.requireNonNull(longArrays.get(key));
+    List<Long> longs = new ArrayList<>(array.length);
+
+    for (long l : array) {
+      longs.add(l);
+    }
+
+    return longs;
+  }
+
 
   public boolean hasFloat(@NonNull String key) {
     return floats.containsKey(key);
@@ -295,6 +310,17 @@ public class Data {
       return this;
     }
 
+    public Builder putLongListAsArray(@NonNull String key, @NonNull List<Long> value) {
+      long[] longs = new long[value.size()];
+
+      for (int i = 0; i < value.size(); i++) {
+        longs[i] = value.get(i);
+      }
+
+      longArrays.put(key, longs);
+      return this;
+    }
+
     public Builder putFloat(@NonNull String key, float value) {
       floats.put(key, value);
       return this;

app/src/main/java/org/thoughtcrime/securesms/jobmanager/workmanager/WorkManagerFactoryMappings.java

@@ -39,6 +39,7 @@ import org.thoughtcrime.securesms.jobs.RotateProfileKeyJob;
 import org.thoughtcrime.securesms.jobs.RotateSignedPreKeyJob;
 import org.thoughtcrime.securesms.jobs.SendDeliveryReceiptJob;
 import org.thoughtcrime.securesms.jobs.SendReadReceiptJob;
+import org.thoughtcrime.securesms.jobs.SendViewedReceiptJob;
 import org.thoughtcrime.securesms.jobs.ServiceOutageDetectionJob;
 import org.thoughtcrime.securesms.jobs.SmsReceiveJob;
 import org.thoughtcrime.securesms.jobs.SmsSendJob;
@@ -90,6 +91,7 @@ public class WorkManagerFactoryMappings {
     put("RotateSignedPreKeyJob", RotateSignedPreKeyJob.KEY);
     put("SendDeliveryReceiptJob", SendDeliveryReceiptJob.KEY);
     put("SendReadReceiptJob", SendReadReceiptJob.KEY);
+    put("SendViewedReceiptJob", SendViewedReceiptJob.KEY);
     put("ServiceOutageDetectionJob", ServiceOutageDetectionJob.KEY);
     put("SmsReceiveJob", SmsReceiveJob.KEY);
     put("SmsSendJob", SmsSendJob.KEY);

app/src/main/java/org/thoughtcrime/securesms/jobs/JobManagerFactories.java

@@ -120,6 +120,7 @@ public final class JobManagerFactories {
       put(RotateSignedPreKeyJob.KEY,                 new RotateSignedPreKeyJob.Factory());
       put(SendDeliveryReceiptJob.KEY,                new SendDeliveryReceiptJob.Factory());
       put(SendReadReceiptJob.KEY,                    new SendReadReceiptJob.Factory(application));
+      put(SendViewedReceiptJob.KEY,                  new SendViewedReceiptJob.Factory(application));
       put(ServiceOutageDetectionJob.KEY,             new ServiceOutageDetectionJob.Factory());
       put(SmsReceiveJob.KEY,                         new SmsReceiveJob.Factory());
       put(SmsSendJob.KEY,                            new SmsSendJob.Factory());

app/src/main/java/org/thoughtcrime/securesms/jobs/PushMediaSendJob.java

@@ -137,6 +137,7 @@ public class PushMediaSendJob extends PushSendJob {
         SyncMessageId id = new SyncMessageId(recipient.getId(), message.getSentTimeMillis());
         DatabaseFactory.getMmsSmsDatabase(context).incrementDeliveryReceiptCount(id, System.currentTimeMillis());
         DatabaseFactory.getMmsSmsDatabase(context).incrementReadReceiptCount(id, System.currentTimeMillis());
+        DatabaseFactory.getMmsSmsDatabase(context).incrementViewedReceiptCount(id, System.currentTimeMillis());
       }
 
       if (unidentified && accessMode == UnidentifiedAccessMode.UNKNOWN && profileKey == null) {

app/src/main/java/org/thoughtcrime/securesms/jobs/PushProcessMessageJob.java

@@ -433,6 +433,7 @@ public final class PushProcessMessageJob extends BaseJob {
 
         if      (message.isReadReceipt())     handleReadReceipt(content, message);
         else if (message.isDeliveryReceipt()) handleDeliveryReceipt(content, message);
+        else if (message.isViewedReceipt())   handleViewedReceipt(content, message);
       } else if (content.getTypingMessage().isPresent()) {
         handleTypingMessage(content, content.getTypingMessage().get());
       } else {
@@ -1572,6 +1573,29 @@ public final class PushProcessMessageJob extends BaseJob {
     ApplicationDependencies.getJobManager().add(new SendDeliveryReceiptJob(RecipientId.fromHighTrust(content.getSender()), message.getTimestamp()));
   }
 
+  private void handleViewedReceipt(@NonNull SignalServiceContent content,
+                                   @NonNull SignalServiceReceiptMessage message)
+  {
+    if (!TextSecurePreferences.isReadReceiptsEnabled(context)) {
+      log(TAG, "Ignoring viewed receipts for IDs: " + Util.join(message.getTimestamps(), ", "));
+      return;
+    }
+
+    log(TAG, "Processing viewed reciepts for IDs: " + Util.join(message.getTimestamps(), ","));
+
+    Recipient                 sender    = Recipient.externalHighTrustPush(context, content.getSender());
+    List<SyncMessageId>       ids       = Stream.of(message.getTimestamps())
+                                                .map(t -> new SyncMessageId(sender.getId(), t))
+                                                .toList();
+    Collection<SyncMessageId> unhandled = DatabaseFactory.getMmsSmsDatabase(context)
+                                                         .incrementViewedReceiptCounts(ids, content.getTimestamp());
+
+    for (SyncMessageId id : unhandled) {
+      warn(TAG, String.valueOf(content.getTimestamp()), "[handleViewedReceipt] Could not find matching message! timestamp: " + id.getTimetamp() + "  author: " + sender.getId());
+      ApplicationDependencies.getEarlyMessageCache().store(sender.getId(), id.getTimetamp(), content);
+    }
+  }
+
   @SuppressLint("DefaultLocale")
   private void handleDeliveryReceipt(@NonNull SignalServiceContent content,
                                      @NonNull SignalServiceReceiptMessage message)

app/src/main/java/org/thoughtcrime/securesms/jobs/SendViewedReceiptJob.java

@@ -0,0 +1,152 @@
+package org.thoughtcrime.securesms.jobs;
+
+
+import android.app.Application;
+
+import androidx.annotation.NonNull;
+
+import org.thoughtcrime.securesms.crypto.UnidentifiedAccessUtil;
+import org.thoughtcrime.securesms.dependencies.ApplicationDependencies;
+import org.thoughtcrime.securesms.jobmanager.Data;
+import org.thoughtcrime.securesms.jobmanager.Job;
+import org.thoughtcrime.securesms.jobmanager.impl.NetworkConstraint;
+import org.thoughtcrime.securesms.logging.Log;
+import org.thoughtcrime.securesms.recipients.Recipient;
+import org.thoughtcrime.securesms.recipients.RecipientId;
+import org.thoughtcrime.securesms.recipients.RecipientUtil;
+import org.thoughtcrime.securesms.util.TextSecurePreferences;
+import org.whispersystems.signalservice.api.SignalServiceMessageSender;
+import org.whispersystems.signalservice.api.crypto.UntrustedIdentityException;
+import org.whispersystems.signalservice.api.messages.SignalServiceReceiptMessage;
+import org.whispersystems.signalservice.api.push.SignalServiceAddress;
+import org.whispersystems.signalservice.api.push.exceptions.PushNetworkException;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+public class SendViewedReceiptJob extends BaseJob {
+
+  public static final String KEY = "SendViewedReceiptJob";
+
+  private static final String TAG = SendViewedReceiptJob.class.getSimpleName();
+
+  private static final String KEY_THREAD          = "thread";
+  private static final String KEY_ADDRESS         = "address";
+  private static final String KEY_RECIPIENT       = "recipient";
+  private static final String KEY_SYNC_TIMESTAMPS = "message_ids";
+  private static final String KEY_TIMESTAMP       = "timestamp";
+
+  private long        threadId;
+  private RecipientId recipientId;
+  private List<Long>  syncTimestamps;
+  private long        timestamp;
+
+  public SendViewedReceiptJob(long threadId, @NonNull RecipientId recipientId, long syncTimestamp) {
+    this(threadId, recipientId, Collections.singletonList(syncTimestamp));
+  }
+
+  public SendViewedReceiptJob(long threadId, @NonNull RecipientId recipientId, @NonNull List<Long> syncTimestamps) {
+    this(new Parameters.Builder()
+                           .addConstraint(NetworkConstraint.KEY)
+                           .setLifespan(TimeUnit.DAYS.toMillis(1))
+                           .setMaxAttempts(Parameters.UNLIMITED)
+                           .build(),
+         threadId,
+         recipientId,
+         syncTimestamps,
+         System.currentTimeMillis());
+  }
+
+  private SendViewedReceiptJob(@NonNull Parameters parameters,
+                               long threadId,
+                               @NonNull RecipientId recipientId,
+                               @NonNull List<Long> syncTimestamps,
+                               long timestamp)
+  {
+    super(parameters);
+
+    this.threadId       = threadId;
+    this.recipientId    = recipientId;
+    this.syncTimestamps = syncTimestamps;
+    this.timestamp      = timestamp;
+  }
+
+  @Override
+  public @NonNull Data serialize() {
+    return new Data.Builder().putString(KEY_RECIPIENT, recipientId.serialize())
+                             .putLongListAsArray(KEY_SYNC_TIMESTAMPS, syncTimestamps)
+                             .putLong(KEY_TIMESTAMP, timestamp)
+                             .putLong(KEY_THREAD, threadId)
+                             .build();
+  }
+
+  @Override
+  public @NonNull String getFactoryKey() {
+    return KEY;
+  }
+
+  @Override
+  public void onRun() throws IOException, UntrustedIdentityException {
+    if (!TextSecurePreferences.isReadReceiptsEnabled(context) || syncTimestamps.isEmpty()) return;
+
+    if (!RecipientUtil.isMessageRequestAccepted(context, threadId)) {
+      Log.w(TAG, "Refusing to send receipts to untrusted recipient");
+      return;
+    }
+
+    Recipient recipient = Recipient.resolved(recipientId);
+    if (recipient.isBlocked()) {
+      Log.w(TAG, "Refusing to send receipts to blocked recipient");
+      return;
+    }
+
+    if (recipient.isGroup()) {
+      Log.w(TAG, "Refusing to send receipts to group");
+      return;
+    }
+
+    SignalServiceMessageSender  messageSender  = ApplicationDependencies.getSignalServiceMessageSender();
+    SignalServiceAddress        remoteAddress  = RecipientUtil.toSignalServiceAddress(context, recipient);
+    SignalServiceReceiptMessage receiptMessage = new SignalServiceReceiptMessage(SignalServiceReceiptMessage.Type.VIEWED,
+                                                                                 syncTimestamps,
+                                                                                 timestamp);
+
+    messageSender.sendReceipt(remoteAddress,
+                              UnidentifiedAccessUtil.getAccessFor(context, Recipient.resolved(recipientId)),
+                              receiptMessage);
+  }
+
+  @Override
+  public boolean onShouldRetry(@NonNull Exception e) {
+    if (e instanceof PushNetworkException) return true;
+    return false;
+  }
+
+  @Override
+  public void onFailure() {
+    Log.w(TAG, "Failed to send read receipts to: " + recipientId);
+  }
+
+  public static final class Factory implements Job.Factory<SendViewedReceiptJob> {
+
+    private final Application application;
+
+    public Factory(@NonNull Application application) {
+      this.application = application;
+    }
+
+    @Override
+    public @NonNull
+    SendViewedReceiptJob create(@NonNull Parameters parameters, @NonNull Data data) {
+      long        timestamp      = data.getLong(KEY_TIMESTAMP);
+      List<Long>  syncTimestamps = data.getLongArrayAsList(KEY_SYNC_TIMESTAMPS);
+      RecipientId recipientId    = data.hasString(KEY_RECIPIENT) ? RecipientId.from(data.getString(KEY_RECIPIENT))
+                                                                 : Recipient.external(application, data.getString(KEY_ADDRESS)).getId();
+      long        threadId       = data.getLong(KEY_THREAD);
+
+      return new SendViewedReceiptJob(parameters, threadId, recipientId, syncTimestamps, timestamp);
+    }
+  }
+}

app/src/main/java/org/thoughtcrime/securesms/messagerequests/MessageRequestRepository.java

@@ -6,6 +6,8 @@ import androidx.annotation.NonNull;
 import androidx.annotation.WorkerThread;
 import androidx.core.util.Consumer;
 
+import com.annimon.stream.Stream;
+
 import org.signal.storageservice.protos.groups.local.DecryptedGroup;
 import org.thoughtcrime.securesms.database.DatabaseFactory;
 import org.thoughtcrime.securesms.database.GroupDatabase;
@@ -19,6 +21,7 @@ import org.thoughtcrime.securesms.groups.GroupManager;
 import org.thoughtcrime.securesms.groups.ui.GroupChangeErrorCallback;
 import org.thoughtcrime.securesms.groups.ui.GroupChangeFailureReason;
 import org.thoughtcrime.securesms.jobs.MultiDeviceMessageRequestResponseJob;
+import org.thoughtcrime.securesms.jobs.SendViewedReceiptJob;
 import org.thoughtcrime.securesms.logging.Log;
 import org.thoughtcrime.securesms.notifications.MarkReadReceiver;
 import org.thoughtcrime.securesms.recipients.LiveRecipient;
@@ -140,6 +143,16 @@ final class MessageRequestRepository {
         ApplicationDependencies.getMessageNotifier().updateNotification(context);
         MarkReadReceiver.process(context, messageIds);
 
+        List<MessageDatabase.MarkedMessageInfo> viewedInfos = DatabaseFactory.getMmsDatabase(context)
+                                                                             .getViewedIncomingMessages(threadId);
+
+        ApplicationDependencies.getJobManager()
+                               .add(new SendViewedReceiptJob(threadId,
+                                                             liveRecipient.getId(),
+                                                             Stream.of(viewedInfos)
+                                                                   .map(info -> info.getSyncMessageId().getTimetamp())
+                                                                   .toList()));
+
         if (TextSecurePreferences.isMultiDevice(context)) {
           ApplicationDependencies.getJobManager().add(MultiDeviceMessageRequestResponseJob.forAccept(liveRecipient.getId()));
         }

app/src/main/java/org/thoughtcrime/securesms/revealable/ViewOnceMessageRepository.java

@@ -8,6 +8,8 @@ import org.thoughtcrime.securesms.database.DatabaseFactory;
 import org.thoughtcrime.securesms.database.MessageDatabase;
 import org.thoughtcrime.securesms.database.MmsDatabase;
 import org.thoughtcrime.securesms.database.model.MmsMessageRecord;
+import org.thoughtcrime.securesms.dependencies.ApplicationDependencies;
+import org.thoughtcrime.securesms.jobs.SendViewedReceiptJob;
 import org.thoughtcrime.securesms.logging.Log;
 import org.thoughtcrime.securesms.util.concurrent.SignalExecutors;
 import org.whispersystems.libsignal.util.guava.Optional;
@@ -26,6 +28,12 @@ class ViewOnceMessageRepository {
     SignalExecutors.BOUNDED.execute(() -> {
       try (MmsDatabase.Reader reader = MmsDatabase.readerFor(mmsDatabase.getMessageCursor(messageId))) {
         MmsMessageRecord record = (MmsMessageRecord) reader.getNext();
+        MessageDatabase.MarkedMessageInfo info = mmsDatabase.setIncomingMessageViewed(record.getId());
+        if (info != null) {
+          ApplicationDependencies.getJobManager().add(new SendViewedReceiptJob(record.getThreadId(),
+                                                                               info.getSyncMessageId().getRecipientId(),
+                                                                               info.getSyncMessageId().getTimetamp()));
+        }
         callback.onComplete(Optional.fromNullable(record));
       }
     });

app/src/main/java/org/thoughtcrime/securesms/sms/MessageSender.java

@@ -505,6 +505,7 @@ public class MessageSender {
 
       mmsSmsDatabase.incrementDeliveryReceiptCount(syncId, System.currentTimeMillis());
       mmsSmsDatabase.incrementReadReceiptCount(syncId, System.currentTimeMillis());
+      mmsSmsDatabase.incrementViewedReceiptCount(syncId, System.currentTimeMillis());
 
       if (message.getExpiresIn() > 0 && !message.isExpirationUpdate()) {
         mmsDatabase.markExpireStarted(messageId);

libsignal/service/src/main/java/org/whispersystems/signalservice/api/SignalServiceMessageSender.java

@@ -534,6 +534,7 @@ public class SignalServiceMessageSender {
 
     if      (message.isDeliveryReceipt()) builder.setType(ReceiptMessage.Type.DELIVERY);
     else if (message.isReadReceipt())     builder.setType(ReceiptMessage.Type.READ);
+    else if (message.isViewedReceipt())   builder.setType(ReceiptMessage.Type.VIEWED);
 
     return container.setReceiptMessage(builder).build().toByteArray();
   }

libsignal/service/src/main/java/org/whispersystems/signalservice/api/messages/SignalServiceContent.java

@@ -632,6 +632,7 @@ public final class SignalServiceContent {
 
     if      (content.getType() == SignalServiceProtos.ReceiptMessage.Type.DELIVERY) type = SignalServiceReceiptMessage.Type.DELIVERY;
     else if (content.getType() == SignalServiceProtos.ReceiptMessage.Type.READ)     type = SignalServiceReceiptMessage.Type.READ;
+    else if (content.getType() == SignalServiceProtos.ReceiptMessage.Type.VIEWED)   type = SignalServiceReceiptMessage.Type.VIEWED;
     else                                                        type = SignalServiceReceiptMessage.Type.UNKNOWN;
 
     return new SignalServiceReceiptMessage(type, content.getTimestampList(), metadata.getTimestamp());

libsignal/service/src/main/java/org/whispersystems/signalservice/api/messages/SignalServiceReceiptMessage.java

@@ -6,7 +6,7 @@ import java.util.List;
 public class SignalServiceReceiptMessage {
 
   public enum Type {
-    UNKNOWN, DELIVERY, READ
+    UNKNOWN, DELIVERY, READ, VIEWED
   }
 
   private final Type       type;
@@ -38,4 +38,8 @@ public class SignalServiceReceiptMessage {
   public boolean isReadReceipt() {
     return type == Type.READ;
   }
+
+  public boolean isViewedReceipt() {
+    return type == Type.VIEWED;
+  }
 }

libsignal/service/src/main/proto/SignalService.proto

@@ -279,6 +279,7 @@ message ReceiptMessage {
   enum Type {
     DELIVERY = 0;
     READ     = 1;
+    VIEWED   = 2;
   }
 
   optional Type   type      = 1;