Optionally restore last session on start

Closes: #534

This patch adds a config option to restore closed sessions on start. So,
if a user had three tabs opened, all three tabs would be restored when
Files is launched again.

Updates
-------
* Searches and mounts aren't serialized anymore. I'm not sure if it
  makes sense to do so, but likely a user would raise an issue if they
  want it.

Author: joshuamegnauth54

i18n/en/cosmic_files.ftl

@@ -197,6 +197,10 @@ match-desktop = Match desktop
 dark = Dark
 light = Light
 
+### Session
+session = Session
+restore-session = Restore previous session on start
+
 # Context menu
 add-to-sidebar = Add to sidebar
 compress = Compress

src/app.rs

@@ -58,7 +58,7 @@ use wayland_client::{protocol::wl_output::WlOutput, Proxy};
 
 use crate::{
     clipboard::{ClipboardCopy, ClipboardKind, ClipboardPaste},
-    config::{AppTheme, Config, DesktopConfig, Favorite, IconSizes, TabConfig},
+    config::{AppTheme, Config, DesktopConfig, Favorite, IconSizes, SessionConfig, TabConfig},
     fl, home_dir,
     key_bind::key_binds,
     localize::LANGUAGE_SORTER,
@@ -69,7 +69,7 @@ use crate::{
     tab::{self, HeadingOptions, ItemMetadata, Location, Tab, HOVER_DURATION},
 };
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Copy, Debug, PartialEq)]
 pub enum Mode {
     App,
     Desktop,
@@ -303,9 +303,11 @@ pub enum Message {
     Rename(Option<Entity>),
     ReplaceResult(ReplaceResult),
     RestoreFromTrash(Option<Entity>),
+    SaveSession,
     SearchActivate,
     SearchClear,
     SearchInput(String),
+    SessionConfig(SessionConfig),
     SystemThemeModeChange(cosmic_theme::ThemeMode),
     TabActivate(Entity),
     TabNext,
@@ -1179,27 +1181,43 @@ impl App {
 
     fn settings(&self) -> Element<Message> {
         // TODO: Should dialog be updated here too?
-        widget::settings::view_column(vec![widget::settings::section()
-            .title(fl!("appearance"))
-            .add({
-                let app_theme_selected = match self.config.app_theme {
-                    AppTheme::Dark => 1,
-                    AppTheme::Light => 2,
-                    AppTheme::System => 0,
-                };
-                widget::settings::item::builder(fl!("theme")).control(widget::dropdown(
-                    &self.app_themes,
-                    Some(app_theme_selected),
-                    move |index| {
-                        Message::AppTheme(match index {
-                            1 => AppTheme::Dark,
-                            2 => AppTheme::Light,
-                            _ => AppTheme::System,
-                        })
-                    },
-                ))
-            })
-            .into()])
+        widget::settings::view_column(vec![
+            widget::settings::section()
+                .title(fl!("appearance"))
+                .add({
+                    let app_theme_selected = match self.config.app_theme {
+                        AppTheme::Dark => 1,
+                        AppTheme::Light => 2,
+                        AppTheme::System => 0,
+                    };
+                    widget::settings::item::builder(fl!("theme")).control(widget::dropdown(
+                        &self.app_themes,
+                        Some(app_theme_selected),
+                        move |index| {
+                            Message::AppTheme(match index {
+                                1 => AppTheme::Dark,
+                                2 => AppTheme::Light,
+                                _ => AppTheme::System,
+                            })
+                        },
+                    ))
+                })
+                .into(),
+            widget::settings::section()
+                .title(fl!("session"))
+                .add(
+                    widget::settings::item::builder(fl!("restore-session")).toggler(
+                        self.config.session.restore,
+                        move |restore| {
+                            Message::SessionConfig(SessionConfig {
+                                restore,
+                                ..Default::default()
+                            })
+                        },
+                    ),
+                )
+                .into(),
+        ])
         .into()
     }
 }
@@ -2355,6 +2373,35 @@ impl Application for App {
                     self.operation(Operation::Restore { paths });
                 }
             }
+            Message::SaveSession => {
+                if self.config.session.restore && self.mode == Mode::App {
+                    let session = SessionConfig {
+                        tabs: Some(
+                            self.tab_model
+                                .iter()
+                                .filter_map(|entity| {
+                                    match self
+                                        .tab_model
+                                        .data::<Tab>(entity)
+                                        .map(|tab| &tab.location)
+                                    {
+                                        // Location's serialization implementation skips variants
+                                        // such as mounts
+                                        // However, we'd still clone all Locations here only for
+                                        // some to be skipped, so it's best to avoid the clone
+                                        loc @ Location::Path(_)
+                                        | Location::Recents
+                                        | Location::Trash => Some(loc.clone()),
+                                        _ => None,
+                                    }
+                                })
+                                .collect(),
+                        ),
+                        ..self.config.session
+                    };
+                    config_set!(session, session);
+                }
+            }
             Message::SearchActivate => {
                 return if self.search_get().is_none() {
                     self.search_set(Some(String::new()))
@@ -2368,6 +2415,9 @@ impl Application for App {
             Message::SearchInput(input) => {
                 return self.search_set(Some(input));
             }
+            Message::SessionConfig(session) => {
+                config_set!(session, session);
+            }
             Message::SystemThemeModeChange(_theme_mode) => {
                 return self.update_config();
             }
@@ -2435,9 +2485,12 @@ impl Application for App {
                 // Remove item
                 self.tab_model.remove(entity);
 
-                // If that was the last tab, close window
+                // If that was the last tab, close window and serialize empty session if necessary
                 if self.tab_model.iter().next().is_none() {
-                    return window::close(window::Id::MAIN);
+                    return Command::batch([
+                        self.update(Message::SaveSession),
+                        window::close(window::Id::MAIN),
+                    ]);
                 }
 
                 return Command::batch([self.update_title(), self.update_watcher()]);
@@ -2698,6 +2751,7 @@ impl Application for App {
                 if let Some(window_id) = self.window_id_opt.take() {
                     return Command::batch([
                         window::close(window_id),
+                        self.update(Message::SaveSession),
                         Command::perform(async move { message::app(Message::MaybeExit) }, |x| x),
                     ]);
                 }

src/config.rs

@@ -9,7 +9,10 @@ use cosmic::{
 };
 use serde::{Deserialize, Serialize};
 
-use crate::{app::App, tab::View};
+use crate::{
+    app::App,
+    tab::{Location, View},
+};
 
 pub const CONFIG_VERSION: u64 = 1;
 
@@ -97,6 +100,7 @@ pub struct Config {
     pub favorites: Vec<Favorite>,
     pub show_details: bool,
     pub tab: TabConfig,
+    pub session: SessionConfig,
 }
 
 impl Config {
@@ -144,6 +148,7 @@ impl Default for Config {
             ],
             show_details: false,
             tab: TabConfig::default(),
+            session: SessionConfig::default(),
         }
     }
 }
@@ -229,3 +234,9 @@ impl IconSizes {
         percent!(self.grid, ICON_SIZE_GRID) as _
     }
 }
+
+#[derive(Clone, Debug, Default, PartialEq, Eq, CosmicConfigEntry, Deserialize, Serialize)]
+pub struct SessionConfig {
+    pub restore: bool,
+    pub tabs: Option<Vec<Location>>,
+}

src/lib.rs

@@ -96,22 +96,25 @@ pub fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     localize::localize();
 
-    let (config_handler, config) = Config::load();
+    let (config_handler, mut config) = Config::load();
 
     let mut locations = Vec::new();
     for arg in env::args().skip(1) {
-        let location = if &arg == "--trash" {
-            Location::Trash
-        } else {
-            match fs::canonicalize(&arg) {
-                Ok(absolute) => Location::Path(absolute),
+        match &*arg {
+            "--trash" => locations.push(Location::Trash),
+            // Override session regardless of config
+            "--no-session" => _ = config.session.tabs.take(),
+            path => match fs::canonicalize(path) {
+                Ok(absolute) => locations.push(Location::Path(absolute)),
                 Err(err) => {
                     log::warn!("failed to canonicalize {:?}: {}", arg, err);
                     continue;
                 }
-            }
-        };
-        locations.push(location);
+            } 
+        }
+    }
+    if let Some(session) = config.session.restore.then(|| config.session.tabs.take()).flatten() {
+        locations.extend(session);
     }
 
     let mut settings = Settings::default();

src/tab.rs

@@ -861,12 +861,15 @@ pub fn scan_desktop(
     items
 }
 
-#[derive(Clone, Debug, Eq, Hash, PartialEq)]
+#[derive(Clone, Debug, Eq, Hash, PartialEq, Deserialize, Serialize)]
 pub enum Location {
+    #[serde(skip)]
     Desktop(PathBuf, String, DesktopConfig),
+    #[serde(skip)]
     Network(String, String),
     Path(PathBuf),
     Recents,
+    #[serde(skip)]
     Search(PathBuf, String, bool, Instant),
     Trash,
 }