let dc_marknoticed_chat() also handle the virtual deaddrop chat

deltachat-ffi/deltachat.h

@@ -1078,9 +1078,9 @@ int             dc_estimate_deletion_cnt    (dc_context_t* context, int from_ser
  * or badge counters eg. on the app-icon.
  * The list is already sorted and starts with the most recent fresh message.
  *
- * Messages belonging to muted chats are not returned,
- * as they should not be notified
- * and also a badge counters should not include messages of muted chats.
+ * Messages belonging to muted chats or to the deaddrop are not returned;
+ * these messages should not be notified
+ * and also badge counters should not include these messages.
  *
  * To get the number of fresh messages for a single chat, muted or not,
  * use dc_get_fresh_msg_cnt().
@@ -1104,7 +1104,8 @@ dc_array_t*     dc_get_fresh_msgs            (dc_context_t* context);
  *
  * @memberof dc_context_t
  * @param context The context object as returned from dc_context_new().
- * @param chat_id The chat ID of which all messages should be marked as being noticed.
+ * @param chat_id The chat ID of which all messages should be marked as being noticed
+ *     (this also works for the virtual chat ID DC_CHAT_ID_DEADDROP).
  */
 void            dc_marknoticed_chat          (dc_context_t* context, uint32_t chat_id);
 

src/chat.rs

@@ -1987,7 +1987,33 @@ pub(crate) async fn marknoticed_chat_if_older_than(
 }
 
 pub async fn marknoticed_chat(context: &Context, chat_id: ChatId) -> Result<(), Error> {
+    // for the virtual deaddrop chat-id,
+    // mark all messages that will appear in the deaddrop as noticed
+    if chat_id.is_deaddrop() {
+        if context
+            .sql
+            .execute(
+                "UPDATE msgs
+                        SET state=?1
+                      WHERE state=?2
+                        AND hidden=0
+                        AND chat_id IN (SELECT id FROM chats WHERE blocked=?3);",
+                paramsv![
+                    MessageState::InNoticed,
+                    MessageState::InFresh,
+                    Blocked::Deaddrop
+                ],
+            )
+            .await?
+            > 0
+        {
+            context.emit_event(EventType::MsgsNoticed(chat_id));
+        }
+        return Ok(());
+    }
+
     // "WHERE" below uses the index `(state, hidden, chat_id)`, see get_fresh_msg_cnt() for reasoning
+    // the additional SELECT statement may speed up things as no write-blocking is needed.
     let exists = context
         .sql
         .exists(