From 1175a5426622f685bd29bd667893eef478eac479 Mon Sep 17 00:00:00 2001
From: Timofey <ouxya@pm.me>
Date: Wed, 8 Jan 2020 22:32:43 +0300
Subject: [PATCH] Synchronize feed updates

---
 podcasts-gtk/src/app.rs    | 22 +++++++++++++++++++++-
 podcasts-gtk/src/utils.rs  | 19 ++++++++++---------
 podcasts-gtk/src/window.rs |  4 +++-
 3 files changed, 34 insertions(+), 11 deletions(-)

diff --git a/podcasts-gtk/src/app.rs b/podcasts-gtk/src/app.rs
index 4876bd0..5d34959 100644
--- a/podcasts-gtk/src/app.rs
+++ b/podcasts-gtk/src/app.rs
@@ -34,7 +34,7 @@ use gettextrs::{bindtextdomain, setlocale, textdomain, LocaleCategory};
 
 use crossbeam_channel::Receiver;
 use fragile::Fragile;
-use podcasts_data::Show;
+use podcasts_data::{Show, Source};
 
 use crate::settings;
 use crate::stacks::PopulatedState;
@@ -138,7 +138,9 @@ pub(crate) enum Action {
     HeaderBarShowTile(String),
     HeaderBarNormal,
     MarkAllPlayerNotification(Arc<Show>),
+    UpdateFeed(Option<Vec<Source>>),
     ShowUpdateNotif(Receiver<bool>),
+    StopUpdating,
     RemoveShow(Arc<Show>),
     ErrorNotification(String),
     InitEpisode(i32),
@@ -248,6 +250,17 @@ impl PdApplication {
                     let notif = InAppNotification::new(&err, 6000, callback, undo_cb);
                     notif.show(&window.overlay);
                 }
+                Action::UpdateFeed(source) => {
+                    if window.updating.get() {
+                        info!("Ignoring feed update request (another one is already running)")
+                    } else {
+                        window.updating.set(true);
+                        utils::refresh_feed(source, window.sender.clone())
+                    }
+                }
+                Action::StopUpdating => {
+                    window.updating.set(false);
+                }
                 Action::ShowUpdateNotif(receiver) => {
                     let sender = window.sender.clone();
                     let callback = move |revealer: gtk::Revealer| match receiver.try_recv() {
@@ -255,9 +268,15 @@ impl PdApplication {
                         Err(TryRecvError::Disconnected) => glib::Continue(false),
                         Ok(_) => {
                             revealer.set_reveal_child(false);
+
+                            sender
+                                .send(Action::StopUpdating)
+                                .expect("Action channel blew up somehow");
+
                             sender
                                 .send(Action::RefreshAllViews)
                                 .expect("Action channel blew up somehow");
+
                             glib::Continue(false)
                         }
                     };
@@ -269,6 +288,7 @@ impl PdApplication {
 
                     let old = window.updater.replace(Some(updater));
                     old.map(|i| i.destroy());
+
                     window
                         .updater
                         .borrow()
diff --git a/podcasts-gtk/src/utils.rs b/podcasts-gtk/src/utils.rs
index 981a3bd..77a81f1 100644
--- a/podcasts-gtk/src/utils.rs
+++ b/podcasts-gtk/src/utils.rs
@@ -203,10 +203,10 @@ pub(crate) fn cleanup(cleanup_date: DateTime<Utc>) {
         .ok();
 }
 
-pub(crate) fn refresh<S>(source: Option<S>, sender: Sender<Action>)
-where
-    S: IntoIterator<Item = Source> + Send + 'static,
-{
+/// Schedule feed refresh
+/// If `source` is None, Refreshes all sources in the database.
+/// Current implementation ignores update request if another update is already running
+pub(crate) fn refresh(source: Option<Vec<Source>>, sender: Sender<Action>) {
     // If we try to update the whole db,
     // Exit early if `source` table is empty
     if source.is_none() {
@@ -220,15 +220,16 @@ where
         };
     }
 
-    refresh_feed(source, sender)
+    sender
+        .send(Action::UpdateFeed(source))
+        .expect("Action channel blew up somehow")
 }
 
 /// Update the rss feed(s) originating from `source`.
 /// If `source` is None, Fetches all the `Source` entries in the database and updates them.
-fn refresh_feed<S>(source: Option<S>, sender: Sender<Action>)
-where
-    S: IntoIterator<Item = Source> + Send + 'static,
-{
+/// Do not call this function directly unless you are sure no other updates are running.
+/// Use `refresh()` instead
+pub(crate) fn refresh_feed(source: Option<Vec<Source>>, sender: Sender<Action>) {
     rayon::spawn(move || {
         let (up_sender, up_receiver) = bounded(1);
         sender
diff --git a/podcasts-gtk/src/window.rs b/podcasts-gtk/src/window.rs
index e73daa1..7227eb3 100644
--- a/podcasts-gtk/src/window.rs
+++ b/podcasts-gtk/src/window.rs
@@ -36,7 +36,7 @@ use crate::widgets::about_dialog;
 use crate::widgets::appnotif::InAppNotification;
 use crate::widgets::player;
 
-use std::cell::RefCell;
+use std::cell::{Cell, RefCell};
 use std::ops::Deref;
 use std::rc::Rc;
 
@@ -65,6 +65,7 @@ pub struct MainWindow {
     pub(crate) content: Rc<Content>,
     pub(crate) headerbar: Rc<Header>,
     pub(crate) player: player::PlayerWrapper,
+    pub(crate) updating: Cell<bool>,
     pub(crate) updater: RefCell<Option<InAppNotification>>,
     pub(crate) sender: Sender<Action>,
     pub(crate) receiver: Receiver<Action>,
@@ -158,6 +159,7 @@ impl MainWindow {
             headerbar: header,
             content,
             player,
+            updating: Cell::new(false),
             updater,
             sender,
             receiver,