Make initiate_key_transfer() non-blocking

CHANGELOG.md

@@ -43,6 +43,9 @@
 - jsonrpc: add `last_seen` property to `Contact` #3590
 - breaking! jsonrpc: replace `Message.quoted_text` and `Message.quoted_message_id` with `Message.quote` #3590
 - add separate stock strings for actions done by contacts to make them easier to translate #3518
+- `dc_initiate_key_transfer()` is non-blocking now. #3553
+  UIs don't need to display a button to cancel sending Autocrypt Setup Message with
+  `dc_stop_ongoing_process()` anymore.
 
 ### Changes
 - order contact lists by "last seen";

deltachat-ffi/deltachat.h

@@ -2174,11 +2174,10 @@ char*           dc_imex_has_backup           (dc_context_t* context, const char*
  * ~~~
  *
  * After that, this function should be called to send the Autocrypt Setup Message.
- * The function creates the setup message and waits until it is really sent.
- * As this may take a while, it is recommended to start the function in a separate thread;
- * to interrupt it, you can use dc_stop_ongoing_process().
+ * The function creates the setup message and adds it to outgoing message queue.
+ * The message is sent asynchronously.
  *
- * After everything succeeded, the required setup code is returned in the following format:
+ * The required setup code is returned in the following format:
  *
  * ~~~
  * 1234-1234-1234-1234-1234-1234-1234-1234-1234
@@ -2244,8 +2243,8 @@ int             dc_continue_key_transfer     (dc_context_t* context, uint32_t ms
  * The ongoing process will return ASAP then, however, it may
  * still take a moment.
  *
- * Typical ongoing processes are started by dc_configure(),
- * dc_initiate_key_transfer() or dc_imex(). As there is always at most only
+ * Typical ongoing processes are started by dc_configure()
+ * or dc_imex(). As there is always at most only
  * one onging process at the same time, there is no need to define _which_ process to exit.
  *
  * @memberof dc_context_t

src/context.rs

@@ -346,6 +346,7 @@ impl Context {
         }
     }
 
+    #[allow(unused)]
     pub(crate) async fn shall_stop_ongoing(&self) -> bool {
         match &*self.running_state.read().await {
             RunningState::Running { .. } => false,

src/imex.rs

@@ -134,19 +134,9 @@ pub async fn has_backup(_context: &Context, dir_name: &Path) -> Result<String> {
 }
 
 /// Initiates key transfer via Autocrypt Setup Message.
+///
+/// Returns setup code.
 pub async fn initiate_key_transfer(context: &Context) -> Result<String> {
-    use futures::future::FutureExt;
-
-    let cancel = context.alloc_ongoing().await?;
-    let res = do_initiate_key_transfer(context)
-        .race(cancel.recv().map(|_| Err(format_err!("canceled"))))
-        .await;
-
-    context.free_ongoing().await;
-    res
-}
-
-async fn do_initiate_key_transfer(context: &Context) -> Result<String> {
     let setup_code = create_setup_code(context);
     /* this may require a keypair to be created. this may take a second ... */
     let setup_file_content = render_setup_file(context, &setup_code).await?;
@@ -171,17 +161,7 @@ async fn do_initiate_key_transfer(context: &Context) -> Result<String> {
     msg.force_plaintext();
     msg.param.set_int(Param::SkipAutocrypt, 1);
 
-    let msg_id = chat::send_msg(context, chat_id, &mut msg).await?;
-    info!(context, "Wait for setup message being sent ...",);
-    while !context.shall_stop_ongoing().await {
-        tokio::time::sleep(std::time::Duration::from_secs(1)).await;
-        if let Ok(msg) = Message::load_from_db(context, msg_id).await {
-            if msg.is_sent() {
-                info!(context, "... setup message sent.",);
-                break;
-            }
-        }
-    }
+    chat::send_msg(context, chat_id, &mut msg).await?;
     // no maybe_add_bcc_self_device_msg() here.
     // the ui shows the dialog with the setup code on this device,
     // it would be too much noise to have two things popping up at the same time.
@@ -980,16 +960,10 @@ mod tests {
     async fn test_key_transfer() -> Result<()> {
         let alice = TestContext::new_alice().await;
 
-        let alice_clone = alice.clone();
-        let key_transfer_task = tokio::task::spawn(async move {
-            let ctx = alice_clone;
-            initiate_key_transfer(&ctx).await
-        });
+        let setup_code = initiate_key_transfer(&alice).await?;
 
-        // Wait for the message to be added to the queue.
-        tokio::time::sleep(std::time::Duration::from_secs(1)).await;
+        // Get Autocrypt Setup Message.
         let sent = alice.pop_sent_msg().await;
-        let setup_code = key_transfer_task.await??;
 
         // Alice sets up a second device.
         let alice2 = TestContext::new().await;