ShowWidget: Try to retain scrollbar adjustment.

hammond-gtk/src/app.rs

@@ -36,6 +36,7 @@ pub enum Action {
     HeaderBarHideUpdateIndicator,
     MarkAllPlayerNotification(Arc<Podcast>),
     RemoveShow(Arc<Podcast>),
+    SetShowWidgetAlignment(Arc<Podcast>),
 }
 
 #[derive(Debug)]
@@ -193,6 +194,13 @@ impl App {
                     let notif = remove_show_notif(pd, sender.clone());
                     notif.show(&overlay);
                 }
+                Ok(Action::SetShowWidgetAlignment(pd)) => {
+                    content
+                        .get_shows()
+                        .set_widget_scroll_alignment(pd)
+                        .map_err(|err| error!("Failed to set ShowWidget alignment: {}", err))
+                        .ok();
+                }
                 Err(_) => (),
             }
 

hammond-gtk/src/main.rs

@@ -5,7 +5,7 @@
     )
 )]
 #![allow(unknown_lints)]
-// #![deny(unused_extern_crates, unused)]
+#![deny(unused_extern_crates, unused)]
 
 extern crate gdk;
 extern crate gdk_pixbuf;

hammond-gtk/src/stacks/show.rs

@@ -3,6 +3,7 @@ use gtk::prelude::*;
 use gtk::Cast;
 
 use failure::Error;
+use send_cell::SendCell;
 
 use hammond_data::dbqueries;
 use hammond_data::Podcast;
@@ -13,7 +14,7 @@ use app::Action;
 use widgets::ShowWidget;
 
 use std::sync::mpsc::Sender;
-use std::sync::Arc;
+use std::sync::{Arc, Mutex};
 
 #[derive(Debug, Clone)]
 pub struct ShowStack {
@@ -21,6 +22,11 @@ pub struct ShowStack {
     sender: Sender<Action>,
 }
 
+lazy_static! {
+    static ref SHOW_WIDGET_VALIGNMENT: Mutex<Option<(i32, SendCell<gtk::Adjustment>)>> =
+        Mutex::new(None);
+}
+
 impl ShowStack {
     pub fn new(sender: Sender<Action>) -> Result<ShowStack, Error> {
         let stack = gtk::Stack::new();
@@ -99,31 +105,23 @@ impl ShowStack {
             .ok_or_else(|| format_err!("Faild to get \"widget\" child from the stack."))?
             .downcast::<gtk::Box>()
             .map_err(|_| format_err!("Failed to downcast stack child to a Box."))?;
-        debug!("Name: {:?}", WidgetExt::get_name(&old));
+
+        let oldname = WidgetExt::get_name(&old);
+        debug!("Name: {:?}", oldname);
+        oldname
+            .clone()
+            .and_then(|id| id.parse().ok())
+            .map(|id| save_alignment(id, &old));
 
         let new = ShowWidget::new(pd, self.sender.clone());
         // Each composite ShowWidget is a gtkBox with the Podcast.id encoded in the
         // gtk::Widget name. It's a hack since we can't yet subclass GObject
         // easily.
-        let oldid = WidgetExt::get_name(&old);
-        let newid = WidgetExt::get_name(&new.container);
-        debug!("Old widget Name: {:?}\nNew widget Name: {:?}", oldid, newid);
-
-        // Only copy the old scrollbar if both widget's represent the same podcast.
-        if newid == oldid {
-            let scrolled_window = old.get_children()
-                .first()
-                .ok_or_else(|| format_err!("Box container has no childs."))?
-                .clone()
-                .downcast::<gtk::ScrolledWindow>()
-                .map_err(|_| format_err!("Failed to downcast stack child to a ScrolledWindow."))?;
-            debug!("Name: {:?}", WidgetExt::get_name(&scrolled_window));
-
-            // Copy the vertical scrollbar adjustment from the old view into the new one.
-            scrolled_window
-                .get_vadjustment()
-                .map(|x| new.set_vadjustment(&x));
-        }
+        debug!(
+            "Old widget Name: {:?}\nNew widget Name: {:?}",
+            oldname,
+            WidgetExt::get_name(&new.container)
+        );
 
         self.stack.remove(&old);
         self.stack.add_named(&new.container, "widget");
@@ -165,6 +163,43 @@ impl ShowStack {
         self.update_widget()
     }
 
+    pub fn set_widget_scroll_alignment(&self, pd: Arc<Podcast>) -> Result<(), Error> {
+        let guard = SHOW_WIDGET_VALIGNMENT
+            .lock()
+            .map_err(|err| format_err!("Failed to lock widget align mutex: {}", err))?;
+
+        if let Some((oldid, ref sendcell)) = *guard {
+            // Only copy the old scrollbar if both widget's represent the same podcast.
+            debug!("PID: {}", pd.id());
+            debug!("OLDID: {}", oldid);
+            if pd.id() != oldid {
+                debug!("Early return");
+                return Ok(());
+            };
+
+            let widget = self.stack
+                .get_child_by_name("widget")
+                .ok_or_else(|| format_err!("Faild to get \"widget\" child from the stack."))?
+                .downcast::<gtk::Box>()
+                .map_err(|_| format_err!("Failed to downcast stack child to a Box."))?;
+
+            let scrolled_window = widget
+                .get_children()
+                .first()
+                .ok_or_else(|| format_err!("Box container has no childs."))?
+                .clone()
+                .downcast::<gtk::ScrolledWindow>()
+                .map_err(|_| format_err!("Failed to downcast stack child to a ScrolledWindow."))?;
+
+            // Copy the vertical scrollbar adjustment from the old view into the new one.
+            sendcell
+                .try_get()
+                .map(|x| scrolled_window.set_vadjustment(&x));
+        }
+
+        Ok(())
+    }
+
     pub fn switch_podcasts_animated(&self) {
         self.stack
             .set_visible_child_full("podcasts", gtk::StackTransitionType::SlideRight);
@@ -179,3 +214,24 @@ impl ShowStack {
         self.stack.clone()
     }
 }
+
+// ATTENTION: EXPECTS THE SHOW WIDGET CONTAINER
+fn save_alignment(oldid: i32, widget: &gtk::Box) -> Result<(), Error> {
+    let scrolled_window = widget
+        .get_children()
+        .first()
+        .ok_or_else(|| format_err!("Box container has no childs."))?
+        .clone()
+        .downcast::<gtk::ScrolledWindow>()
+        .map_err(|_| format_err!("Failed to downcast stack child to a ScrolledWindow."))?;
+
+    if let Ok(mut guard) = SHOW_WIDGET_VALIGNMENT.lock() {
+        let adj = scrolled_window
+            .get_vadjustment()
+            .ok_or_else(|| format_err!("Could not get the adjustment"))?;
+        *guard = Some((oldid, SendCell::new(adj)));
+        debug!("Widget Alignment was saved with ID: {}.", oldid);
+    }
+
+    Ok(())
+}

hammond-gtk/src/widgets/show.rs

@@ -132,12 +132,12 @@ impl ShowWidget {
         let count = dbqueries::get_pd_episodes_count(&pd)?;
 
         let (sender_, receiver) = bounded(1);
-        rayon::spawn(move || {
+        rayon::spawn(clone!(pd => move || {
             let episodes = dbqueries::get_pd_episodeswidgets(&pd).unwrap();
             // The receiver can be dropped if there's an early return
             // like on show without episodes for example.
             sender_.send(episodes).ok();
-        });
+        }));
 
         if count == 0 {
             let builder = gtk::Builder::new_from_resource("/org/gnome/hammond/gtk/empty_show.ui");
@@ -158,7 +158,13 @@ impl ShowWidget {
                 EpisodeWidget::new(ep, sender.clone()).container
             });
 
-            lazy_load(episodes, list.clone(), constructor, || {});
+            let callback = clone!(pd, sender => move || {
+                sender.send(Action::SetShowWidgetAlignment(pd.clone()))
+                    .map_err(|err| error!("Action Sender: {}", err))
+                    .ok();
+            });
+
+            lazy_load(episodes, list.clone(), constructor, callback);
 
             glib::Continue(false)
         });