Use a single save_queue on the editor

2 files changed, 68 insertions, 151 deletions

diff --git a/helix-view/src/document.rs b/helix-view/src/document.rs
index 0774e516..9fa1241e 100644
--- a/helix-view/src/document.rs
+++ b/helix-view/src/document.rs
@@ -13,10 +13,6 @@ use std::future::Future;
 use std::path::{Path, PathBuf};
 use std::str::FromStr;
 use std::sync::Arc;
-use tokio::sync::mpsc::error::TryRecvError;
-use tokio::sync::mpsc::{UnboundedReceiver, UnboundedSender};
-
-use tokio::sync::Mutex;
 
 use helix_core::{
     encoding,
@@ -134,9 +130,6 @@ pub struct Document {
     last_saved_revision: usize,
     version: i32, // should be usize?
     pub(crate) modified_since_accessed: bool,
-    save_sender: Option<UnboundedSender<DocumentSavedEventFuture>>,
-    save_receiver: Option<UnboundedReceiver<DocumentSavedEventFuture>>,
-    current_save: Arc<Mutex<Option<DocumentSavedEventFuture>>>,
 
     diagnostics: Vec<Diagnostic>,
     language_server: Option<Arc<helix_lsp::Client>>,
@@ -357,7 +350,6 @@ impl Document {
         let encoding = encoding.unwrap_or(encoding::UTF_8);
         let changes = ChangeSet::new(&text);
         let old_state = None;
-        let (save_sender, save_receiver) = tokio::sync::mpsc::unbounded_channel();
 
         Self {
             id: DocumentId::default(),
@@ -378,9 +370,6 @@ impl Document {
             savepoint: None,
             last_saved_revision: 0,
             modified_since_accessed: false,
-            save_sender: Some(save_sender),
-            save_receiver: Some(save_receiver),
-            current_save: Arc::new(Mutex::new(None)),
             language_server: None,
         }
     }
@@ -519,21 +508,26 @@ impl Document {
         &mut self,
         path: Option<P>,
         force: bool,
-    ) -> Result<(), anyhow::Error> {
-        self.save_impl::<futures_util::future::Ready<_>, _>(path, force)
+    ) -> Result<
+        impl Future<Output = Result<DocumentSavedEvent, anyhow::Error>> + 'static + Send,
+        anyhow::Error,
+    > {
+        let path = path.map(|path| path.into());
+        self.save_impl(path, force)
+
+        // futures_util::future::Ready<_>,
     }
 
     /// The `Document`'s text is encoded according to its encoding and written to the file located
     /// at its `path()`.
-    fn save_impl<F, P>(&mut self, path: Option<P>, force: bool) -> Result<(), anyhow::Error>
-    where
-        F: Future<Output = Result<Transaction, FormatterError>> + 'static + Send,
-        P: Into<PathBuf>,
-    {
-        if self.save_sender.is_none() {
-            bail!("saves are closed for this document!");
-        }
-
+    fn save_impl(
+        &mut self,
+        path: Option<PathBuf>,
+        force: bool,
+    ) -> Result<
+        impl Future<Output = Result<DocumentSavedEvent, anyhow::Error>> + 'static + Send,
+        anyhow::Error,
+    > {
         log::debug!(
             "submitting save of doc '{:?}'",
             self.path().map(|path| path.to_string_lossy())
@@ -544,7 +538,7 @@ impl Document {
         let text = self.text().clone();
 
         let path = match path {
-            Some(path) => helix_core::path::get_canonicalized_path(&path.into())?,
+            Some(path) => helix_core::path::get_canonicalized_path(&path)?,
             None => {
                 if self.path.is_none() {
                     bail!("Can't save with no path set!");
@@ -564,7 +558,7 @@ impl Document {
         let encoding = self.encoding;
 
         // We encode the file according to the `Document`'s encoding.
-        let save_event = async move {
+        let future = async move {
             use tokio::fs::File;
             if let Some(parent) = path.parent() {
                 // TODO: display a prompt asking the user if the directories should be created
@@ -604,107 +598,15 @@ impl Document {
             Ok(event)
         };
 
-        self.save_sender
-            .as_mut()
-            .unwrap()
-            .send(Box::pin(save_event))
-            .map_err(|err| anyhow!("failed to send save event: {}", err))
-    }
-
-    pub async fn await_save(&mut self) -> Option<DocumentSavedEventResult> {
-        self.await_save_impl(true).await
-    }
-
-    async fn await_save_impl(&mut self, block: bool) -> Option<DocumentSavedEventResult> {
-        let mut current_save = self.current_save.lock().await;
-        if let Some(ref mut save) = *current_save {
-            log::trace!("reawaiting save of '{:?}'", self.path());
-            let result = save.await;
-            *current_save = None;
-            log::trace!("reawait save of '{:?}' result: {:?}", self.path(), result);
-            return Some(result);
-        }
-
-        // return early if the receiver is closed
-        let rx = self.save_receiver.as_mut()?;
-
-        let save_req = if block {
-            rx.recv().await
-        } else {
-            let msg = rx.try_recv();
-
-            if let Err(err) = msg {
-                match err {
-                    TryRecvError::Empty => return None,
-                    TryRecvError::Disconnected => None,
-                }
-            } else {
-                msg.ok()
-            }
-        };
-
-        let save = match save_req {
-            Some(save) => save,
-            None => {
-                self.save_receiver = None;
-                return None;
-            }
-        };
-
-        // save a handle to the future so that when a poll on this
-        // function gets cancelled, we don't lose it
-        *current_save = Some(save);
-        log::trace!("awaiting save of '{:?}'", self.path());
-
-        let result = (*current_save).as_mut().unwrap().await;
-        *current_save = None;
-
-        log::trace!("save of '{:?}' result: {:?}", self.path(), result);
-
-        Some(result)
-    }
-
-    /// Flushes the queue of pending writes. If any fail,
-    /// it stops early before emptying the rest of the queue.
-    pub async fn try_flush_saves(&mut self) -> Option<DocumentSavedEventResult> {
-        self.flush_saves_impl(false).await
-    }
-
-    async fn flush_saves_impl(&mut self, block: bool) -> Option<DocumentSavedEventResult> {
-        let mut final_result = None;
-
-        while let Some(save_event) = self.await_save_impl(block).await {
-            let is_err = match &save_event {
-                Ok(event) => {
-                    self.set_last_saved_revision(event.revision);
-                    false
-                }
-                Err(err) => {
-                    log::error!(
-                        "error saving document {:?}: {}",
-                        self.path().map(|path| path.to_string_lossy()),
-                        err
-                    );
-                    true
-                }
-            };
-
-            final_result = Some(save_event);
-
-            if is_err {
-                break;
-            }
-        }
-
-        final_result
+        Ok(future)
     }
 
     /// Prepares the Document for being closed by stopping any new writes
     /// and flushing through the queue of pending writes. If any fail,
     /// it stops early before emptying the rest of the queue.
     pub async fn close(&mut self) -> Option<DocumentSavedEventResult> {
-        self.save_sender.take();
-        self.flush_saves_impl(true).await
+        // TODO
+        None
     }
 
     /// Detect the programming language based on the file type.
diff --git a/helix-view/src/editor.rs b/helix-view/src/editor.rs
index fbd0b2b0..c4789ee2 100644
--- a/helix-view/src/editor.rs
+++ b/helix-view/src/editor.rs
@@ -1,6 +1,6 @@
 use crate::{
     clipboard::{get_clipboard_provider, ClipboardProvider},
-    document::{DocumentSavedEventResult, Mode},
+    document::{DocumentSavedEventFuture, DocumentSavedEventResult, Mode},
     graphics::{CursorKind, Rect},
     info::Info,
     input::KeyEvent,
@@ -9,7 +9,7 @@ use crate::{
     Document, DocumentId, View, ViewId,
 };
 
-use futures_util::stream::{select_all::SelectAll, FuturesUnordered};
+use futures_util::stream::select_all::SelectAll;
 use futures_util::{future, StreamExt};
 use helix_lsp::Call;
 use tokio_stream::wrappers::UnboundedReceiverStream;
@@ -29,7 +29,7 @@ use tokio::{
     time::{sleep, Duration, Instant, Sleep},
 };
 
-use anyhow::Error;
+use anyhow::{anyhow, Error};
 
 pub use helix_core::diagnostic::Severity;
 pub use helix_core::register::Registers;
@@ -644,12 +644,20 @@ pub struct Breakpoint {
     pub log_message: Option<String>,
 }
 
+use futures_util::stream::{Flatten, Once};
+
 pub struct Editor {
     /// Current editing mode.
     pub mode: Mode,
     pub tree: Tree,
     pub next_document_id: DocumentId,
     pub documents: BTreeMap<DocumentId, Document>,
+
+    // We Flatten<> to resolve the inner DocumentSavedEventFuture. For that we need a stream of streams, hence the Once<>.
+    // https://stackoverflow.com/a/66875668
+    pub saves: HashMap<DocumentId, UnboundedSender<Once<DocumentSavedEventFuture>>>,
+    pub save_queue: SelectAll<Flatten<UnboundedReceiverStream<Once<DocumentSavedEventFuture>>>>,
+
     pub count: Option<std::num::NonZeroUsize>,
     pub selected_register: Option<char>,
     pub registers: Registers,
@@ -751,6 +759,8 @@ impl Editor {
             tree: Tree::new(area),
             next_document_id: DocumentId::default(),
             documents: BTreeMap::new(),
+            saves: HashMap::new(),
+            save_queue: SelectAll::new(),
             count: None,
             selected_register: None,
             macro_recording: None,
@@ -1083,6 +1093,12 @@ impl Editor {
             self.new_document(doc)
         };
 
+        let (save_sender, save_receiver) = tokio::sync::mpsc::unbounded_channel();
+        self.saves.insert(id, save_sender);
+
+        let stream = UnboundedReceiverStream::new(save_receiver).flatten();
+        self.save_queue.push(stream);
+
         self.switch(id, action);
         Ok(id)
     }
@@ -1095,38 +1111,21 @@ impl Editor {
         self._refresh();
     }
 
-    pub async fn close_document(
-        &mut self,
-        doc_id: DocumentId,
-        force: bool,
-    ) -> Result<(), CloseError> {
+    pub fn close_document(&mut self, doc_id: DocumentId, force: bool) -> Result<(), CloseError> {
         let doc = match self.documents.get_mut(&doc_id) {
             Some(doc) => doc,
             None => return Err(CloseError::DoesNotExist),
         };
-
-        // flush out any pending writes first to clear the modified status
-        if let Some(Err(err)) = doc.try_flush_saves().await {
-            return Err(CloseError::SaveError(err));
-        }
-
         if !force && doc.is_modified() {
             return Err(CloseError::BufferModified(doc.display_name().into_owned()));
         }
 
-        if let Some(Err(err)) = doc.close().await {
-            return Err(CloseError::SaveError(err));
-        }
+        // This will also disallow any follow-up writes
+        self.saves.remove(&doc_id);
 
-        // Don't fail the whole write because the language server could not
-        // acknowledge the close
         if let Some(language_server) = doc.language_server() {
-            if let Err(err) = language_server
-                .text_document_did_close(doc.identifier())
-                .await
-            {
-                log::error!("Error closing doc in language server: {}", err);
-            }
+            // TODO: track error
+            tokio::spawn(language_server.text_document_did_close(doc.identifier()));
         }
 
         enum Action {
@@ -1188,6 +1187,28 @@ impl Editor {
         Ok(())
     }
 
+    pub fn save<P: Into<PathBuf>>(
+        &mut self,
+        doc_id: DocumentId,
+        path: Option<P>,
+        force: bool,
+    ) -> anyhow::Result<()> {
+        // convert a channel of futures to pipe into main queue one by one
+        // via stream.then() ? then push into main future
+
+        let path = path.map(|path| path.into());
+        let doc = doc_mut!(self, &doc_id);
+        let future = doc.save(path, force)?;
+        // TODO: if no self.saves for that doc id then bail
+        // bail!("saves are closed for this document!");
+        use futures_util::stream;
+        self.saves[&doc_id]
+            .send(stream::once(Box::pin(future)))
+            .map_err(|err| anyhow!("failed to send save event: {}", err))?;
+
+        Ok(())
+    }
+
     pub fn resize(&mut self, area: Rect) {
         if self.tree.resize(area) {
             self._refresh();
@@ -1307,16 +1328,10 @@ impl Editor {
     }
 
     pub async fn wait_event(&mut self) -> EditorEvent {
-        let mut saves: FuturesUnordered<_> = self
-            .documents
-            .values_mut()
-            .map(Document::await_save)
-            .collect();
-
         tokio::select! {
             biased;
 
-            Some(Some(event)) = saves.next() => {
+            Some(event) = self.save_queue.next() => {
                 EditorEvent::DocumentSaved(event)
             }
             Some(config_event) = self.config_events.1.recv() => {