mail/view: cancel previous jobs on MailView drop/update

When MailView loads a new thread or gets dropped, cancel all pending
jobs.

Signed-off-by: Manos Pitsidianakis <manos@pitsidianak.is>

meli/src/jobs.rs

@@ -40,7 +40,7 @@ pub use futures::channel::oneshot;
 use indexmap::IndexMap;
 use melib::{log, smol, utils::datetime, uuid::Uuid, UnixTimestamp};
 
-use crate::types::{ThreadEvent, UIEvent};
+use crate::types::{StatusEvent, ThreadEvent, UIEvent};
 
 type AsyncTask = async_task::Runnable;
 
@@ -425,8 +425,14 @@ pub struct JoinHandle<T> {
 }
 
 impl<T> JoinHandle<T> {
-    pub fn cancel(&self) {
-        *self.cancel.lock().unwrap() = true;
+    pub fn cancel(&self) -> Option<StatusEvent> {
+        let mut lck = self.cancel.lock().unwrap();
+        if !*lck {
+            *lck = true;
+            Some(StatusEvent::JobCanceled(self.job_id))
+        } else {
+            None
+        }
     }
 }
 

meli/src/mail/view.rs

@@ -53,7 +53,7 @@ pub use envelope::EnvelopeView;
 
 /// Contains an Envelope view, with sticky headers, a pager for the body, and
 /// subviews for more menus
-#[derive(Debug, Default)]
+#[derive(Debug)]
 pub struct MailView {
     coordinates: Option<(AccountHash, MailboxHash, EnvelopeHash)>,
     dirty: bool,
@@ -62,6 +62,7 @@ pub struct MailView {
     theme_default: ThemeAttribute,
     active_jobs: HashSet<JobId>,
     state: MailViewState,
+    main_loop_handler: MainLoopHandler,
     id: ComponentId,
 }
 
@@ -72,6 +73,7 @@ impl Clone for MailView {
             forward_dialog: None,
             state: MailViewState::default(),
             active_jobs: self.active_jobs.clone(),
+            main_loop_handler: self.main_loop_handler.clone(),
             ..*self
         }
     }
@@ -83,6 +85,17 @@ impl std::fmt::Display for MailView {
     }
 }
 
+impl Drop for MailView {
+    fn drop(&mut self) {
+        if let MailViewState::LoadingBody { ref mut handle, .. } = self.state {
+            if let Some(canceled) = handle.cancel() {
+                self.main_loop_handler
+                    .send(UIEvent::StatusEvent(canceled).into());
+            }
+        }
+    }
+}
+
 impl MailView {
     pub fn new(
         coordinates: Option<(AccountHash, MailboxHash, EnvelopeHash)>,
@@ -96,6 +109,7 @@ impl MailView {
             theme_default: crate::conf::value(context, "mail.view.body"),
             active_jobs: Default::default(),
             state: MailViewState::default(),
+            main_loop_handler: context.main_loop_handler.clone(),
             id: ComponentId::default(),
         };
 
@@ -222,6 +236,11 @@ impl MailView {
         new_coordinates: (AccountHash, MailboxHash, EnvelopeHash),
         context: &mut Context,
     ) {
+        if let MailViewState::LoadingBody { ref mut handle, .. } = self.state {
+            if let Some(canceled) = handle.cancel() {
+                context.replies.push_back(UIEvent::StatusEvent(canceled));
+            }
+        }
         if self.coordinates != Some(new_coordinates) {
             self.coordinates = Some(new_coordinates);
             self.init_futures(context);

meli/src/types.rs

@@ -84,7 +84,13 @@ pub enum ThreadEvent {
 
 impl From<RefreshEvent> for ThreadEvent {
     fn from(event: RefreshEvent) -> Self {
-        ThreadEvent::RefreshMailbox(Box::new(event))
+        Self::RefreshMailbox(Box::new(event))
+    }
+}
+
+impl From<UIEvent> for ThreadEvent {
+    fn from(event: UIEvent) -> Self {
+        Self::UIEvent(event)
     }
 }