merge pull request #52 from mariinkys/file_watcher

feat: detect external file modifications

Author: mariinkys

Cargo.lock

@@ -34,6 +34,7 @@ icu_collator.workspace = true
 icu_locale.workspace = true
 font-kit.workspace = true
 grep.workspace = true
+notify.workspace = true
 
 # PDF Generation Generation
 gotenberg_pdf.workspace = true
@@ -79,6 +80,7 @@ gotenberg_pdf = { git = "https://github.com/mariinkys/gotenberg_pdf" }
 font-kit = "0.14.3"
 image = { version= "0.25.10", default-features=false }
 grep = "0.4.1"
+notify = "8.2.0"
 
 [workspace.dependencies.libcosmic]
 git = "https://github.com/pop-os/libcosmic.git"

Cargo.toml

@@ -24,6 +24,9 @@ delete-confirmation = Are you sure you want to delete this file/folder and it's
 save-changes-closing = Save changes before closing?
 save-warning = You have unsaved changes. If you continue without saving, these changes will be lost.
 discard-changes = Discard Changes
+file-changed-externally = The file has been changed from another application
+reload = Reload File
+keep-my-version = Keep Current Version
 
 <#-- Appearance -->
 appearance = Appearance

i18n/en/cedilla.ftl

@@ -30,7 +30,7 @@ use slotmap::Key as SlotMapKey;
 use std::any::TypeId;
 use std::collections::{HashMap, VecDeque};
 use std::path::{Path, PathBuf};
-use std::sync::Arc;
+use std::sync::{Arc, Mutex};
 use widgets::{TextEditor, text_editor};
 
 pub mod app_menu;
@@ -162,9 +162,11 @@ pub enum Message {
     /// Callback after opening a new file
     OpenFile(Result<(PathBuf, Arc<String>), anywho::Error>),
     /// Callback after saving the current file
-    FileSaved(Result<PathBuf, anywho::Error>),
+    FileSaved(Option<Result<PathBuf, anywho::Error>>),
     /// Callback after asking to close a file discarding changes
     DiscardChanges(DiscardChangesAction),
+    /// Fired when the watcher detects an external change to the open file
+    ExternalFileChanged(PathBuf),
 
     /// Deletes the given node entity of the navbar folder or file
     DeleteNode(cosmic::widget::segmented_button::Entity),
@@ -649,6 +651,11 @@ impl cosmic::Application for AppModel {
         struct ConfigSubscription;
         struct ThemeSubscription;
 
+        let watched_path = match &self.state {
+            State::Ready { editor, .. } => editor.path.clone(),
+            _ => None,
+        };
+
         // Add subscriptions which are always active.
         let subscriptions = vec![
             // Watch for key_bind inputs
@@ -695,6 +702,8 @@ impl cosmic::Application for AppModel {
                 }
                 Message::ConfigInput(ConfigInput::SystemThemeModeChange)
             }),
+            // Watch for external file changes
+            file_watch_subscription(watched_path),
         ];
 
         Subscription::batch(subscriptions)
@@ -736,6 +745,7 @@ impl cosmic::Application for AppModel {
             Message::OpenFile(result) => self.handle_open_file(result),
             Message::FileSaved(result) => self.handle_file_saved(result),
             Message::DiscardChanges(action) => self.handle_discard_changes(action),
+            Message::ExternalFileChanged(path) => self.handle_external_file_changed(path),
 
             // Vault / Node
             Message::DeleteNode(entity) => self.handle_delete_node(entity),
@@ -1320,6 +1330,74 @@ fn cedilla_main_view<'a>(
     }
 }
 
+/// Watches for external changes on the currently open file
+fn file_watch_subscription(path: Option<PathBuf>) -> Subscription<Message> {
+    use cosmic::iced::futures::SinkExt;
+    use cosmic::iced_futures::futures::channel::mpsc;
+    use notify::{EventKind, RecursiveMode, Watcher, recommended_watcher};
+
+    let Some(path) = path else {
+        return Subscription::none();
+    };
+
+    Subscription::run_with(path, |path| {
+        let path_owned = path.clone();
+
+        cosmic::iced_futures::stream::channel(
+            16,
+            move |mut output: mpsc::Sender<Message>| async move {
+                let (tx, rx) = std::sync::mpsc::channel::<PathBuf>();
+                let rx = Arc::new(Mutex::new(rx));
+
+                let mut watcher =
+                    match recommended_watcher(move |res: notify::Result<notify::Event>| {
+                        if let Ok(event) = res {
+                            let is_relevant =
+                                matches!(event.kind, EventKind::Modify(_) | EventKind::Create(_));
+                            if is_relevant {
+                                for p in event.paths {
+                                    let _ = tx.send(p);
+                                }
+                            }
+                        }
+                    }) {
+                        Ok(w) => w,
+                        Err(e) => {
+                            eprintln!("file_watcher: failed to create watcher: {e}");
+                            return;
+                        }
+                    };
+
+                if let Err(e) = watcher.watch(&path_owned, RecursiveMode::NonRecursive) {
+                    eprintln!("file_watcher: failed to watch {path_owned:?}: {e}");
+                    return;
+                }
+
+                let _watcher = watcher;
+
+                loop {
+                    let rx2 = Arc::clone(&rx);
+                    let changed_path =
+                        match tokio::task::spawn_blocking(move || rx2.lock().unwrap().recv()).await
+                        {
+                            Ok(Ok(p)) => p,
+                            _ => return,
+                        };
+
+                    if changed_path == path_owned {
+                        let _ = output
+                            .send(Message::ExternalFileChanged(changed_path))
+                            .await;
+
+                        tokio::time::sleep(std::time::Duration::from_millis(300)).await;
+                        while rx.lock().unwrap().try_recv().is_ok() {}
+                    }
+                }
+            },
+        )
+    })
+}
+
 /// Returns the text editor scrollable Id
 fn editor_scrollable_id() -> widget::Id {
     widget::Id::new("editor_scroll")

src/app.rs

@@ -20,6 +20,8 @@ pub struct EditorState {
     pub scroll: EditorScrollState,
     /// Holds the state of the search faetures of the editor
     pub search: EditorSearchState,
+    /// Helper field to not open the external changes dialog when we save a file, move, delete...
+    pub ignore_next_external_change: bool,
 }
 
 /// Allows us to correctly follow the cursor with the scrollbar

src/app/core/editor.rs

@@ -24,6 +24,8 @@ pub enum DialogPage {
     MoveNode(cosmic::widget::segmented_button::Entity, Option<PathBuf>),
     /// Dialog for when closing a file with pending changes
     ConfirmCloseFile(DiscardChangesAction),
+    /// Open file was modified externally
+    ExternalFileModified(PathBuf),
 }
 
 impl DialogPage {
@@ -194,6 +196,32 @@ impl DialogPage {
                     ])
                     .spacing(spacing.space_xxs),
                 ),
+            DialogPage::ExternalFileModified(path) => {
+                let file_name = path
+                    .file_name()
+                    .and_then(|n| n.to_str())
+                    .unwrap_or("this file");
+
+                widget::dialog()
+                    .title(fl!("file-changed-externally"))
+                    .primary_action(
+                        widget::button::suggested(fl!("reload"))
+                            .on_press(Message::DialogAction(DialogAction::DialogComplete)),
+                    )
+                    .secondary_action(
+                        widget::button::standard(fl!("keep-my-version"))
+                            .on_press(Message::DialogAction(DialogAction::KeepMyFile)),
+                    )
+                    .control(
+                        widget::column::with_children(vec![
+                            widget::text::body(format!(
+                                "\"{file_name}\" was modified by another program."
+                            ))
+                            .into(),
+                        ])
+                        .spacing(spacing.space_xxs),
+                    )
+            }
         };
 
         Some(dialog.into())
@@ -203,6 +231,8 @@ impl DialogPage {
 /// Represents an Action related to a Dialog
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub enum DialogAction {
+    /// File has been modified externally and user want's to keep it's version of the file
+    KeepMyFile,
     /// Asks to open the [`DialogPage`] for creating a new vault file
     OpenNewVaultFileDialog,
     /// Asks to open the [`DialogPage`] for creating a new vault folder
@@ -233,6 +263,10 @@ impl DialogAction {
         dialog_state: &DialogState,
     ) -> Task<cosmic::Action<Message>> {
         match self {
+            DialogAction::KeepMyFile => {
+                dialog_pages.pop_front();
+                Task::done(cosmic::action::app(Message::SaveFile))
+            }
             DialogAction::OpenNewVaultFileDialog => {
                 dialog_pages.push_back(DialogPage::NewVaultFile(String::new()));
                 widget::text_input::focus(dialog_state.dialog_text_input.clone())
@@ -283,6 +317,12 @@ impl DialogAction {
                                 return Task::done(cosmic::action::app(Message::SaveFile));
                             }
                         },
+
+                        DialogPage::ExternalFileModified(path) => {
+                            return Task::done(cosmic::action::app(Message::DiscardChanges(
+                                DiscardChangesAction::OpenFile(path.clone()),
+                            )));
+                        }
                     }
                 }
                 Task::none()