handle webxdc updates for not downloaded instances (#3487)

* save webxdc-updates for not yet downloaded messages, that are probably webxdc instances then

* test webxdc updates received while instance is not yet downloaded

* keep msg_id on downloading messages

keeping msg_id on downloading messages
has the advantage that webxdc updates and other references to the msg_id
can be processed as usual.

if a message expands to multiple msg_id,
the last one is kept,
however, this does not affect webxdc at all.

(alternatives may be to update `msgs_status_updates`
but that seems more complicated and even less elegant,
another alternative would be to use different keys (eg. `rfc274_mid`),
but that also seems not to be much easier and would waste space as well.
also both alternatives would need adaption for other foreign keys)

* update CHANGELOG

* do not emit WebxdcStatusUpdate event in case the message is not yet downloaded

* move DELETE/UPDATE to an transaction

* make merge_msg_id() a little less confusing

* use some webxdc-update-param from placeholder

(the placeholder may be updated,
the just downloaded messages is not)

* more precise function name

* test not directly downloading status updates

* test not directly downloading mdn

src/webxdc.rs

@@ -14,6 +14,7 @@ use tokio::io::AsyncReadExt;
 use crate::chat::Chat;
 use crate::contact::ContactId;
 use crate::context::Context;
+use crate::download::DownloadState;
 use crate::message::{Message, MessageState, MsgId, Viewtype};
 use crate::mimeparser::SystemMessage;
 use crate::param::Param;
@@ -330,10 +331,12 @@ impl Context {
 
         let status_update_serial = StatusUpdateSerial(u32::try_from(rowid)?);
 
-        self.emit_event(EventType::WebxdcStatusUpdate {
-            msg_id: instance.id,
-            status_update_serial,
-        });
+        if instance.viewtype == Viewtype::Webxdc {
+            self.emit_event(EventType::WebxdcStatusUpdate {
+                msg_id: instance.id,
+                status_update_serial,
+            });
+        }
 
         Ok(status_update_serial)
     }
@@ -475,6 +478,8 @@ impl Context {
         } else if let Some(parent) = msg.parent(self).await? {
             if parent.viewtype == Viewtype::Webxdc {
                 (msg.timestamp_sort, parent, true)
+            } else if parent.download_state() != DownloadState::Done {
+                (msg.timestamp_sort, parent, false)
             } else {
                 bail!("receive_status_update: message is not the child of a webxdc message.")
             }
@@ -730,7 +735,7 @@ mod tests {
     use crate::chatlist::Chatlist;
     use crate::config::Config;
     use crate::contact::Contact;
-    use crate::receive_imf::receive_imf;
+    use crate::receive_imf::{receive_imf, receive_imf_inner};
     use crate::test_utils::TestContext;
 
     use super::*;
@@ -1038,6 +1043,71 @@ mod tests {
         Ok(())
     }
 
+    #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+    async fn test_webxdc_update_for_not_downloaded_instance() -> Result<()> {
+        // Alice sends a larger instance and an update
+        let alice = TestContext::new_alice().await;
+        let bob = TestContext::new_bob().await;
+        let chat = alice.create_chat(&bob).await;
+        bob.set_config(Config::DownloadLimit, Some("40000")).await?;
+        let mut alice_instance = create_webxdc_instance(
+            &alice,
+            "chess.xdc",
+            include_bytes!("../test-data/webxdc/chess.xdc"),
+        )
+        .await?;
+        let sent1 = alice.send_msg(chat.id, &mut alice_instance).await;
+        let alice_instance = Message::load_from_db(&alice, sent1.sender_msg_id).await?;
+        alice
+            .send_webxdc_status_update(
+                alice_instance.id,
+                r#"{"payload": 7, "summary":"sum", "document":"doc"}"#,
+                "bla",
+            )
+            .await?;
+        alice.flush_status_updates().await?;
+        let sent2 = alice.pop_sent_msg().await;
+
+        // Bob does not download instance but already receives update
+        receive_imf_inner(
+            &bob,
+            &alice_instance.rfc724_mid,
+            sent1.payload().as_bytes(),
+            false,
+            Some(70790),
+            false,
+        )
+        .await?;
+        let bob_instance = bob.get_last_msg().await;
+        bob_instance.chat_id.accept(&bob).await?;
+        bob.recv_msg(&sent2).await;
+        assert_eq!(bob_instance.download_state, DownloadState::Available);
+
+        // Bob downloads instance, updates should be assigned correctly
+        receive_imf_inner(
+            &bob,
+            &alice_instance.rfc724_mid,
+            sent1.payload().as_bytes(),
+            false,
+            None,
+            false,
+        )
+        .await?;
+        let bob_instance = bob.get_last_msg().await;
+        assert_eq!(bob_instance.viewtype, Viewtype::Webxdc);
+        assert_eq!(bob_instance.download_state, DownloadState::Done);
+        assert_eq!(
+            bob.get_webxdc_status_updates(bob_instance.id, StatusUpdateSerial(0))
+                .await?,
+            r#"[{"payload":7,"document":"doc","summary":"sum","serial":1,"max_serial":1}]"#
+        );
+        let info = bob_instance.get_webxdc_info(&bob).await?;
+        assert_eq!(info.document, "doc");
+        assert_eq!(info.summary, "sum");
+
+        Ok(())
+    }
+
     #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
     async fn test_delete_webxdc_instance() -> Result<()> {
         let t = TestContext::new_alice().await;