merge: branch 'betterlib' into dev

move features and tools into codemp library, trying to decouple stuff
from nvim. also implemented a proper outgoing queue and operation
composing, making connections more reliable

src/client/nvim/codemp.lua

@@ -49,13 +49,13 @@ local function hook_callbacks(path, buffer)
 		{
 			callback = function(args)
 				local cursor = vim.api.nvim_win_get_cursor(0)
+				pcall(M.cursor, path, cursor[1], cursor[2]) -- TODO log errors
 				if cursor[1] == last_line then
 					return
 				end
 				last_line = cursor[1]
 				local lines = vim.api.nvim_buf_get_lines(args.buf, 0, -1, false)
 				pcall(M.replace, path, vim.fn.join(lines, "\n")) -- TODO log errors
-				pcall(M.cursor, path, cursor[1], cursor[2]) -- TODO log errors
 			end,
 			buffer = buffer,
 			group = codemp_autocmds,
@@ -111,6 +111,7 @@ vim.api.nvim_create_user_command('Connect',
 					-- print(vim.fn.join(data, "\n"))
 				end,
 				stderr_buffered = false,
+				env = { RUST_BACKTRACE = 1 }
 			}
 		)
 		if M.jobid <= 0 then

src/client/nvim/main.rs

@@ -1,6 +1,8 @@
-use std::{net::TcpStream, sync::Mutex};
+use std::sync::Arc;
+use std::{net::TcpStream, sync::Mutex, collections::BTreeMap};
 
-use codemp::client::CodempClient;
+use codemp::operation::{OperationController, OperationFactory};
+use codemp::{client::CodempClient, operation::OperationProcessor};
 use codemp::proto::buffer_client::BufferClient;
 use rmpv::Value;
 
@@ -9,12 +11,12 @@ use tokio::io::Stdout;
 use clap::Parser;
 
 use nvim_rs::{compat::tokio::Compat, create::tokio as create, Handler, Neovim};
-use tonic::async_trait;
 use tracing::{error, warn, debug, info};
 
 #[derive(Clone)]
 struct NeovimHandler {
 	client: CodempClient,
+	factories: Arc<Mutex<BTreeMap<String, Arc<OperationController>>>>,
 }
 
 fn nullable_optional_str(args: &Vec<Value>, index: usize) -> Option<String> {
@@ -33,7 +35,13 @@ fn default_zero_number(args: &Vec<Value>, index: usize) -> i64 {
 	nullable_optional_number(args, index).unwrap_or(0)
 }
 
-#[async_trait]
+impl NeovimHandler {
+	fn buffer_controller(&self, path: &String) -> Option<Arc<OperationController>> {
+		Some(self.factories.lock().unwrap().get(path)?.clone())
+	}
+}
+
+#[tonic::async_trait]
 impl Handler for NeovimHandler {
 	type Writer = Compat<Stdout>;
 
@@ -69,16 +77,18 @@ impl Handler for NeovimHandler {
 				}
 				let path = default_empty_str(&args, 0);
 				let txt = default_empty_str(&args, 1);
-				let pos = default_zero_number(&args, 2) as u64;
-				let mut c = self.client.clone();
-				match c.insert(path, txt, pos).await {
-					Ok(res) => {
-						match res {
-							true => Ok(Value::Nil),
-							false => Err(Value::from("rejected")),
+				let mut pos = default_zero_number(&args, 2) as i64;
+				
+				if pos <= 0 { pos = 0 } // TODO wtf vim??
+
+				match self.buffer_controller(&path) {
+					None => Err(Value::from("no controller for given path")),
+					Some(controller) => {
+						match controller.apply(controller.insert(&txt, pos as u64)).await {
+							Err(e) => Err(Value::from(format!("could not send insert: {}", e))),
+							Ok(_res) => Ok(Value::Nil),
 						}
-					},
-					Err(e) => Err(Value::from(format!("could not send insert: {}", e))),
+					}
 				}
 			},
 
@@ -90,13 +100,12 @@ impl Handler for NeovimHandler {
 				let pos = default_zero_number(&args, 1) as u64;
 				let count = default_zero_number(&args, 2) as u64;
 
-				let mut c = self.client.clone();
-				match c.delete(path, pos, count).await {
-					Ok(res) => match res {
-						true => Ok(Value::Nil),
-						false => Err(Value::from("rejected")),
-					},
-					Err(e) => Err(Value::from(format!("could not send insert: {}", e))),
+				match self.buffer_controller(&path) {
+					None => Err(Value::from("no controller for given path")),
+					Some(controller) => match controller.apply(controller.delete(pos, count)).await {
+						Err(e) => Err(Value::from(format!("could not send delete: {}", e))),
+						Ok(_res) => Ok(Value::Nil),
+					}
 				}
 			},
 
@@ -107,13 +116,12 @@ impl Handler for NeovimHandler {
 				let path = default_empty_str(&args, 0);
 				let txt = default_empty_str(&args, 1);
 
-				let mut c = self.client.clone();
-				match c.replace(path, txt).await {
-					Ok(res) => match res {
-						true => Ok(Value::Nil),
-						false => Err(Value::from("rejected")),
-					},
-					Err(e) => Err(Value::from(format!("could not send replace: {}", e))),
+				match self.buffer_controller(&path) {
+					None => Err(Value::from("no controller for given path")),
+					Some(controller) => match controller.apply(controller.replace(&txt)).await {
+						Err(e) => Err(Value::from(format!("could not send replace: {}", e))),
+						Ok(_res) => Ok(Value::Nil),
+					}
 				}
 			},
 
@@ -129,63 +137,72 @@ impl Handler for NeovimHandler {
 
 				let mut c = self.client.clone();
 
-				let buf = buffer.clone();
-				match c.attach(path, move |x| {
-					let lines : Vec<String> = x.split("\n").map(|x| x.to_string()).collect();
-					let b = buf.clone();
-					tokio::spawn(async move {
-						if let Err(e) = b.set_lines(0, -1, false, lines).await {
-							error!("could not update buffer: {}", e);
-						}
-					});
-				}).await {
+				match c.attach(path.clone()).await {
 					Err(e) => Err(Value::from(format!("could not attach to stream: {}", e))),
-					Ok(content) => {
-						let lines : Vec<String> = content.split("\n").map(|x| x.to_string()).collect();
-						if let Err(e) = buffer.set_lines(0, -1, false, lines).await {
-							error!("could not update buffer: {}", e);
+					Ok(controller) => {
+						let _controller = controller.clone();
+						let lines : Vec<String> = _controller.content().split("\n").map(|x| x.to_string()).collect();
+						match buffer.set_lines(0, -1, false, lines).await {
+							Err(e) => Err(Value::from(format!("could not sync buffer: {}", e))),
+							Ok(()) => {
+								tokio::spawn(async move {
+									loop {
+										_controller.wait().await;
+										let lines : Vec<String> = _controller.content().split("\n").map(|x| x.to_string()).collect();
+										if let Err(e) = buffer.set_lines(0, -1, false, lines).await {
+											error!("could not update buffer: {}", e);
+										}
+									}
+								});
+								self.factories.lock().unwrap().insert(path, controller);
+								Ok(Value::Nil)
+							}
 						}
-						Ok(Value::Nil)
 					},
 				}
 			},
 
 			"detach" => {
-				if args.len() < 1 {
-					return Err(Value::from("no path given"));
-				}
-				let path = default_empty_str(&args, 0);
-				let mut c = self.client.clone();
-				c.detach(path);
-				Ok(Value::Nil)
+				Err(Value::from("unimplemented! try with :q!"))
+				// if args.len() < 1 {
+				// 	return Err(Value::from("no path given"));
+				// }
+				// let path = default_empty_str(&args, 0);
+				// let mut c = self.client.clone();
+				// c.detach(path);
+				// Ok(Value::Nil)
 			},
 
 			"listen" => {
-				if args.len() < 1 {
-					return Err(Value::from("no path given"));
-				}
-				let path = default_empty_str(&args, 0);
-				let mut c = self.client.clone();
-
 				let ns = nvim.create_namespace("Cursor").await
 					.map_err(|e| Value::from(format!("could not create namespace: {}", e)))?;
 
 				let buf = nvim.get_current_buf().await
 					.map_err(|e| Value::from(format!("could not get current buf: {}", e)))?;
 				
-				match c.listen(path, move |cur| {
-					let _b = buf.clone();
-					tokio::spawn(async move {
-						if let Err(e) = _b.clear_namespace(ns, 0, -1).await {
-							error!("could not clear previous cursor highlight: {}", e);
-						}
-						if let Err(e) = _b.add_highlight(ns, "ErrorMsg", cur.row-1, cur.col, cur.col+1).await {
-							error!("could not create highlight for cursor: {}", e);
-						}
-					});
-				}).await {
-					Ok(()) => Ok(Value::Nil),
+				let mut c = self.client.clone();
+				match c.listen().await {
 					Err(e) => Err(Value::from(format!("could not listen cursors: {}", e))),
+					Ok(cursor) => {
+						let mut sub = cursor.sub();
+						debug!("spawning cursor processing worker");
+						tokio::spawn(async move {
+							loop {
+								match sub.recv().await {
+									Err(e) => return error!("error receiving cursor update from controller: {}", e),
+									Ok((_usr, cur)) => {
+										if let Err(e) = buf.clear_namespace(ns, 0, -1).await {
+											error!("could not clear previous cursor highlight: {}", e);
+										}
+										if let Err(e) = buf.add_highlight(ns, "ErrorMsg", cur.start.row-1, cur.start.col, cur.start.col+1).await {
+											error!("could not create highlight for cursor: {}", e);
+										}
+									}
+								}
+							}
+						});
+						Ok(Value::Nil)
+					},
 				}
 			},
 
@@ -199,8 +216,8 @@ impl Handler for NeovimHandler {
 
 				let mut c = self.client.clone();
 				match c.cursor(path, row, col).await {
-					Ok(()) => Ok(Value::Nil),
-					Err(e) => Err(Value::from(format!("could not send cursor update: {}", e))),
+					Ok(_) => Ok(Value::Nil),
+					Err(e) => Err(Value:: from(format!("could not update cursor: {}", e))),
 				}
 			},
 
@@ -259,6 +276,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
 
 	let handler: NeovimHandler = NeovimHandler {
 		client: client.into(),
+		factories: Arc::new(Mutex::new(BTreeMap::new())),
 	};
 
 	let (_nvim, io_handler) = create::new_parent(handler).await;

src/lib/client.rs

@@ -1,194 +1,138 @@
-/// TODO better name for this file
+use std::sync::Arc;
 
-use std::{sync::{Arc, RwLock}, collections::BTreeMap};
-use tracing::{error, warn, info};
+use operational_transform::OperationSeq;
+use tonic::{transport::Channel, Status};
+use tracing::{error, warn};
 use uuid::Uuid;
 
 use crate::{
-	opfactory::AsyncFactory,
-	proto::{buffer_client::BufferClient, BufferPayload, OperationRequest, RawOp, CursorMov},
-	tonic::{transport::Channel, Status, Streaming},
+	cursor::{CursorController, CursorStorage},
+	operation::{OperationController, OperationProcessor},
+	proto::{buffer_client::BufferClient, BufferPayload, OperationRequest, CursorMov},
 };
 
-pub type FactoryStore = Arc<RwLock<BTreeMap<String, Arc<AsyncFactory>>>>;
-
-impl From::<BufferClient<Channel>> for CodempClient {
-	fn from(x: BufferClient<Channel>) -> CodempClient {
-		CodempClient {
-			id: Uuid::new_v4(),
-			client:x,
-			factories: Arc::new(RwLock::new(BTreeMap::new())),
-		}
-	}
-}
-
 #[derive(Clone)]
 pub struct CodempClient {
-	id: Uuid,
+	id: String,
 	client: BufferClient<Channel>,
-	factories: FactoryStore,
+}
+
+impl From::<BufferClient<Channel>> for CodempClient {
+	fn from(value: BufferClient<Channel>) -> Self {
+		CodempClient { id: Uuid::new_v4().to_string(), client: value }
+	}
 }
 
 impl CodempClient {
-	fn get_factory(&self, path: &String) -> Result<Arc<AsyncFactory>, Status> {
-		match self.factories.read().unwrap().get(path) {
-			Some(f) => Ok(f.clone()),
-			None => Err(Status::not_found("no active buffer for given path")),
-		}
-	}
-
-	pub fn add_factory(&self, path: String, factory:Arc<AsyncFactory>) {
-		self.factories.write().unwrap().insert(path, factory);
+	pub fn new(id: String, client: BufferClient<Channel>) -> Self {
+		CodempClient { id, client }
 	}
 
 	pub async fn create(&mut self, path: String, content: Option<String>) -> Result<bool, Status> {
 		let req = BufferPayload {
-			path: path.clone(),
-			content: content.clone(),
-			user: self.id.to_string(),
+			path, content,
+			user: self.id.clone(),
 		};
 
-		let res = self.client.create(req).await?.into_inner();
+		let res = self.client.create(req).await?;
 
-		Ok(res.accepted)
+		Ok(res.into_inner().accepted)
 	}
 
-	pub async fn insert(&mut self, path: String, txt: String, pos: u64) -> Result<bool, Status> {
-		let factory = self.get_factory(&path)?;
-		match factory.insert(txt, pos).await {
-			Err(e) => Err(Status::internal(format!("invalid operation: {}", e))),
-			Ok(op) => {
-				let req = OperationRequest {
-					path,
-					hash: "".into(),
-					user: self.id.to_string(),
-					opseq: serde_json::to_string(&op)
-						.map_err(|_| Status::invalid_argument("could not serialize opseq"))?,
-				};
-				let res = self.client.edit(req).await?.into_inner();
-				if let Err(e) = factory.ack(op.clone()).await {
-					error!("could not ack op '{:?}' : {}", op, e);
-				}
-				Ok(res.accepted)
-			},
-		}
-	}
-
-	pub async fn delete(&mut self, path: String, pos: u64, count: u64) -> Result<bool, Status> {
-		let factory = self.get_factory(&path)?;
-		match factory.delete(pos, count).await {
-			Err(e) => Err(Status::internal(format!("invalid operation: {}", e))),
-			Ok(op) => {
-				let req = OperationRequest {
-					path,
-					hash: "".into(),
-					user: self.id.to_string(),
-					opseq: serde_json::to_string(&op)
-						.map_err(|_| Status::invalid_argument("could not serialize opseq"))?,
-				};
-				let res = self.client.edit(req).await?.into_inner();
-				if let Err(e) = factory.ack(op.clone()).await {
-					error!("could not ack op '{:?}' : {}", op, e);
-				}
-				Ok(res.accepted)
-			},
-		}
-	}
-
-	pub async fn replace(&mut self, path: String, txt: String) -> Result<bool, Status> {
-		let factory = self.get_factory(&path)?;
-		match factory.replace(txt).await {
-			Err(e) => Err(Status::internal(format!("invalid operation: {}", e))),
-			Ok(op) => {
-				let req = OperationRequest {
-					path,
-					hash: "".into(),
-					user: self.id.to_string(),
-					opseq: serde_json::to_string(&op)
-						.map_err(|_| Status::invalid_argument("could not serialize opseq"))?,
-				};
-				let res = self.client.edit(req).await?.into_inner();
-				if let Err(e) = factory.ack(op.clone()).await {
-					error!("could not ack op '{:?}' : {}", op, e);
-				}
-				Ok(res.accepted)
-			},
-		}
-	}
-
-	pub async fn cursor(&mut self, path: String, row: i64, col: i64) -> Result<(), Status> {
-		let req = CursorMov {
-			path, user: self.id.to_string(),
-			row, col,
-		};
-		let _res = self.client.cursor(req).await?.into_inner();
-		Ok(())
-	}
-
-	pub async fn listen<F>(&mut self, path: String, callback: F) -> Result<(), Status>
-	where F : Fn(CursorMov) -> () + Send + 'static {
+	pub async fn listen(&mut self) -> Result<Arc<CursorController>, Status> {
 		let req = BufferPayload {
-			path,
+			path: "".into(),
 			content: None,
-			user: self.id.to_string(),
+			user: self.id.clone(),
 		};
+
 		let mut stream = self.client.listen(req).await?.into_inner();
+
+		let controller = Arc::new(CursorController::new());
+
+		let _controller = controller.clone();
 		tokio::spawn(async move {
-			// TODO catch some errors
-			while let Ok(Some(x)) = stream.message().await {
-				callback(x)
+			loop {
+				match stream.message().await {
+					Err(e)      => break error!("error receiving cursor: {}", e),
+					Ok(None)    => break,
+					Ok(Some(x)) => { _controller.update(x); },
+				}
 			}
 		});
-		Ok(())
+
+		Ok(controller)
 	}
 
-	pub async fn attach<F>(&mut self, path: String, callback: F) -> Result<String, Status>
-	where F : Fn(String) -> () + Send + 'static {
-		let content = self.sync(path.clone()).await?;
-		let factory = Arc::new(AsyncFactory::new(Some(content.clone())));
-		self.add_factory(path.clone(), factory.clone());
+	pub async fn attach(&mut self, path: String) -> Result<Arc<OperationController>, Status> {
 		let req = BufferPayload {
-			path,
+			path: path.clone(),
 			content: None,
-			user: self.id.to_string(),
+			user: self.id.clone(),
 		};
-		let stream = self.client.attach(req).await?.into_inner();
-		tokio::spawn(async move { Self::worker(stream, factory, callback).await } );
-		Ok(content)
-	}
 
-	pub fn detach(&mut self, path: String) {
-		self.factories.write().unwrap().remove(&path);
-		info!("|| detached from buffer");
-	}
+		let content = self.client.sync(req.clone())
+			.await?
+			.into_inner()
+			.content;
 
-	async fn sync(&mut self, path: String) -> Result<String, Status> {
-		let res = self.client.sync(
-			BufferPayload {
-				path, content: None, user: self.id.to_string(),
+		let mut stream = self.client.attach(req).await?.into_inner();
+
+		let factory = Arc::new(OperationController::new(content.unwrap_or("".into())));
+
+		let _factory = factory.clone();
+		tokio::spawn(async move {
+			loop {
+				match stream.message().await {
+					Err(e) => break error!("error receiving update: {}", e),
+					Ok(None) => break, // clean exit
+					Ok(Some(x)) => match serde_json::from_str::<OperationSeq>(&x.opseq) {
+						Err(e) => break error!("error deserializing opseq: {}", e),
+						Ok(v) => match _factory.process(v).await {
+							Err(e) => break error!("could not apply operation from server: {}", e),
+							Ok(_txt) => {
+								// send event containing where the change happened
+							}
+						}
+					},
+				}
 			}
-		).await?;
-		Ok(res.into_inner().content.unwrap_or("".into()))
+		});
+
+		let mut _client = self.client.clone();
+		let _uid = self.id.clone();
+		let _factory = factory.clone();
+		let _path = path.clone();
+		tokio::spawn(async move {
+			while let Some(op) = _factory.poll().await {
+				let req = OperationRequest {
+					hash: "".into(),
+					opseq: serde_json::to_string(&op).unwrap(),
+					path: _path.clone(),
+					user: _uid.clone(),
+				};
+				match _client.edit(req).await {
+					Ok(res) => match res.into_inner().accepted {
+						true => { _factory.ack().await; },
+						false => {
+							warn!("server rejected operation, retrying in 1s");
+							tokio::time::sleep(std::time::Duration::from_secs(1)).await;
+						}
+					},
+					Err(e) => error!("could not send edit: {}", e),
+				}
+			}
+		});
+
+		Ok(factory)
 	}
 
-	async fn worker<F>(mut stream: Streaming<RawOp>, factory: Arc<AsyncFactory>, callback: F)
-	where F : Fn(String) -> () {
-		info!("|> buffer worker started");
-		loop {
-			match stream.message().await {
-				Err(e) => break error!("error receiving change: {}", e),
-				Ok(v) => match v {
-					None => break warn!("stream closed"),
-					Some(operation) => match serde_json::from_str(&operation.opseq) {
-						Err(e) => break error!("could not deserialize opseq: {}", e),
-						Ok(op) => match factory.process(op).await {
-							Err(e) => break error!("desynched: {}", e),
-							Ok(x) => callback(x),
-						},
-					}
-				},
-			}
-		}
-		info!("[] buffer worker stopped");
+	pub async fn cursor(&mut self, path: String, row: i64, col: i64) -> Result<bool, Status> {
+		let req = CursorMov {
+			path, row, col,
+			user: self.id.clone(),
+		};
+		let res = self.client.cursor(req).await?.into_inner();
+		Ok(res.accepted)
 	}
 }

src/lib/cursor.rs

@@ -0,0 +1,87 @@
+use std::{collections::HashMap, sync::Mutex};
+
+use tokio::sync::broadcast;
+use tracing::{info, error, debug, warn};
+
+use crate::proto::CursorMov;
+
+/// Note that this differs from any hashmap in its put method: no &mut!
+pub trait CursorStorage {
+	fn get(&self, id: &String) -> Option<Cursor>;
+	fn put(&self, id: String, val: Cursor);
+
+	fn update(&self, event: CursorMov) -> Option<Cursor> {
+		let mut cur = self.get(&event.user)?;
+		cur.buffer = event.path;
+		cur.start = (event.row, event.col).into();
+		self.put(event.user, cur.clone());
+		Some(cur)
+	}
+}
+
+#[derive(Copy, Clone, Debug, Default)]
+pub struct Position {
+	pub row: i64,
+	pub col: i64,
+}
+
+impl From::<(i64, i64)> for Position {
+	fn from((row, col): (i64, i64)) -> Self {
+		Position { row, col }
+	}
+}
+
+#[derive(Clone, Debug, Default)]
+pub struct Cursor {
+	pub buffer: String,
+	pub start: Position,
+	pub end:   Position,
+}
+
+pub struct CursorController {
+	users: Mutex<HashMap<String, Cursor>>,
+	bus: broadcast::Sender<(String, Cursor)>,
+	_bus_keepalive: Mutex<broadcast::Receiver<(String, Cursor)>>,
+}
+
+impl CursorController {
+	pub fn new() -> Self {
+		let (tx, _rx) = broadcast::channel(64);
+		CursorController {
+			users: Mutex::new(HashMap::new()),
+			bus: tx,
+			_bus_keepalive: Mutex::new(_rx),
+		}
+	}
+
+	pub fn sub(&self) -> broadcast::Receiver<(String, Cursor)> {
+		self.bus.subscribe()
+	}
+}
+
+impl CursorStorage for CursorController {
+	fn update(&self, event: CursorMov) -> Option<Cursor> {
+		debug!("processing cursor event: {:?}", event);
+		let mut cur = self.get(&event.user).unwrap_or(Cursor::default());
+		cur.buffer = event.path;
+		cur.start = (event.row, event.col).into();
+		cur.end = (event.row, event.col).into();
+		self.put(event.user.clone(), cur.clone());
+		if let Err(e) = self.bus.send((event.user, cur.clone())) {
+			error!("could not broadcast cursor event: {}", e);
+		} else { // this is because once there are no receivers, nothing else can be sent
+			if let Err(e) = self._bus_keepalive.lock().unwrap().try_recv() {
+				warn!("could not consume event: {}", e);
+			}
+		}
+		Some(cur)
+	}
+	
+	fn get(&self, id: &String) -> Option<Cursor> {
+		Some(self.users.lock().unwrap().get(id)?.clone())
+	}
+
+	fn put(&self, id: String, val: Cursor) {
+		self.users.lock().unwrap().insert(id, val);
+	}
+}

src/lib/lib.rs

@@ -1,6 +1,7 @@
 pub mod proto;
-pub mod opfactory;
 pub mod client;
+pub mod operation;
+pub mod cursor;
 
 pub use tonic;
 pub use tokio;

src/lib/operation/factory.rs

@@ -0,0 +1,53 @@
+use operational_transform::OperationSeq;
+use similar::{TextDiff, ChangeTag};
+
+pub trait OperationFactory {
+	fn content(&self) -> String;
+
+	fn replace(&self, txt: &str) -> OperationSeq {
+		let mut out = OperationSeq::default();
+		let content = self.content();
+		if content == txt {
+			return out; // TODO this won't work, should we return a noop instead?
+		}
+
+		let diff = TextDiff::from_chars(content.as_str(), txt);
+
+		for change in diff.iter_all_changes() {
+			match change.tag() {
+				ChangeTag::Equal => out.retain(1),
+				ChangeTag::Delete => out.delete(1),
+				ChangeTag::Insert => out.insert(change.value()),
+			}
+		}
+
+		out
+	}
+
+	fn insert(&self, txt: &str, pos: u64) -> OperationSeq {
+		let mut out = OperationSeq::default();
+		let total = self.content().len() as u64;
+		out.retain(pos);
+		out.insert(txt);
+		out.retain(total - pos);
+		out
+	}
+
+	fn delete(&self, pos: u64, count: u64) -> OperationSeq {
+		let mut out = OperationSeq::default();
+		let len = self.content().len() as u64;
+		out.retain(pos - count);
+		out.delete(count);
+		out.retain(len - pos);
+		out
+	}
+
+	fn cancel(&self, pos: u64, count: u64) -> OperationSeq {
+		let mut out = OperationSeq::default();
+		let len = self.content().len() as u64;
+		out.retain(pos);
+		out.delete(count);
+		out.retain(len - (pos+count));
+		out
+	}
+}

src/lib/operation/mod.rs

@@ -0,0 +1,5 @@
+pub mod factory;
+pub mod processor;
+
+pub use processor::{OperationController, OperationProcessor};
+pub use factory::OperationFactory;

src/lib/operation/processor.rs

@@ -0,0 +1,93 @@
+use std::{sync::Mutex, collections::VecDeque};
+
+use operational_transform::{OperationSeq, OTError};
+use tokio::sync::watch;
+
+use crate::operation::factory::OperationFactory;
+
+
+#[tonic::async_trait]
+pub trait OperationProcessor : OperationFactory {
+	async fn apply(&self, op: OperationSeq) -> Result<String, OTError>;
+	async fn process(&self, op: OperationSeq) -> Result<String, OTError>;
+
+	async fn poll(&self) -> Option<OperationSeq>;
+	async fn ack(&self)  -> Option<OperationSeq>;
+	async fn wait(&self);
+}
+
+
+pub struct OperationController {
+	text: Mutex<String>,
+	queue: Mutex<VecDeque<OperationSeq>>,
+	last: Mutex<watch::Receiver<OperationSeq>>,
+	notifier: watch::Sender<OperationSeq>,
+	changed: Mutex<watch::Receiver<()>>,
+	changed_notifier: watch::Sender<()>,
+}
+
+impl OperationController {
+	pub fn new(content: String) -> Self {
+		let (tx, rx) = watch::channel(OperationSeq::default());
+		let (done, wait) = watch::channel(());
+		OperationController {
+			text: Mutex::new(content),
+			queue: Mutex::new(VecDeque::new()),
+			last: Mutex::new(rx),
+			notifier: tx,
+			changed: Mutex::new(wait),
+			changed_notifier: done,
+		}
+	}
+}
+
+impl OperationFactory for OperationController {
+	fn content(&self) -> String {
+		self.text.lock().unwrap().clone()
+	}
+}
+
+#[tonic::async_trait]
+impl OperationProcessor for OperationController {
+	async fn apply(&self, op: OperationSeq) -> Result<String, OTError> {
+		let txt = self.content();
+		let res = op.apply(&txt)?;
+		*self.text.lock().unwrap() = res.clone();
+		self.queue.lock().unwrap().push_back(op.clone());
+		self.notifier.send(op);
+		Ok(res)
+	}
+
+	async fn wait(&self) {
+		let mut blocker = self.changed.lock().unwrap().clone();
+		blocker.changed().await;
+		blocker.changed().await;
+	}
+
+	async fn process(&self, mut op: OperationSeq) -> Result<String, OTError> {
+		let mut queue = self.queue.lock().unwrap();
+		for el in queue.iter_mut() {
+			(op, *el) = op.transform(el)?;
+		}
+		let txt = self.content();
+		let res = op.apply(&txt)?;
+		*self.text.lock().unwrap() = res.clone();
+		self.changed_notifier.send(());
+		Ok(res)
+	}
+
+	async fn poll(&self) -> Option<OperationSeq> {
+		let len = self.queue.lock().unwrap().len();
+		if len <= 0 {
+			let mut recv = self.last.lock().unwrap().clone();
+			// TODO this is not 100% reliable
+			recv.changed().await; // acknowledge current state
+			recv.changed().await; // wait for a change in state
+		}
+		Some(self.queue.lock().unwrap().get(0)?.clone())
+	}
+
+	async fn ack(&self) -> Option<OperationSeq> {
+		self.queue.lock().unwrap().pop_front()
+	}
+}

src/lib/opfactory.rs

@@ -1,234 +0,0 @@
-use std::collections::VecDeque;
-
-use operational_transform::{OperationSeq, OTError};
-use similar::TextDiff;
-use tokio::sync::{mpsc, watch, oneshot};
-use tracing::{error, warn};
-
-#[derive(Clone)]
-pub struct OperationFactory {
-	content: String,
-	queue: VecDeque<OperationSeq>,
-}
-
-impl OperationFactory {
-	pub fn new(init: Option<String>) -> Self {
-		OperationFactory {
-			content: init.unwrap_or(String::new()),
-			queue: VecDeque::new(),
-		}
-	}
-
-	fn apply(&mut self, op: OperationSeq) -> Result<OperationSeq, OTError> {
-		if op.is_noop() { return Err(OTError) }
-		self.content = op.apply(&self.content)?;
-		self.queue.push_back(op.clone());
-		Ok(op)
-	}
-
-	// TODO remove the need for this
-	pub fn content(&self) -> String {
-		self.content.clone()
-	}
-
-	pub fn check(&self, txt: &str) -> bool {
-		self.content == txt
-	}
-
-	pub fn replace(&mut self, txt: &str) -> Result<OperationSeq, OTError> {
-		let mut out = OperationSeq::default();
-		if self.content == txt { // TODO throw and error rather than wasting everyone's resources
-			return Err(OTError); // nothing to do
-		}
-
-		let diff = TextDiff::from_chars(self.content.as_str(), txt);
-
-		for change in diff.iter_all_changes() {
-			match change.tag() {
-				similar::ChangeTag::Equal => out.retain(1),
-				similar::ChangeTag::Delete => out.delete(1),
-				similar::ChangeTag::Insert => out.insert(change.value()),
-			}
-		}
-
-		self.content = out.apply(&self.content)?;
-		Ok(out)
-	}
-
-	pub fn insert(&mut self, txt: &str, pos: u64) -> Result<OperationSeq, OTError> {
-		let mut out = OperationSeq::default();
-		let total = self.content.len() as u64;
-		out.retain(pos);
-		out.insert(txt);
-		out.retain(total - pos);
-		Ok(self.apply(out)?)
-	}
-
-	pub fn delete(&mut self, pos: u64, count: u64) -> Result<OperationSeq, OTError> {
-		let mut out = OperationSeq::default();
-		let len = self.content.len() as u64;
-		out.retain(pos - count);
-		out.delete(count);
-		out.retain(len - pos);
-		Ok(self.apply(out)?)
-	}
-
-	pub fn cancel(&mut self, pos: u64, count: u64) -> Result<OperationSeq, OTError> {
-		let mut out = OperationSeq::default();
-		let len = self.content.len() as u64;
-		out.retain(pos);
-		out.delete(count);
-		out.retain(len - (pos+count));
-		Ok(self.apply(out)?)
-	}
-
-	pub fn ack(&mut self, op: OperationSeq) -> Result<(), OTError> { // TODO use a different error?
-		// TODO is manually iterating from behind worth the manual search boilerplate?
-		for (i, o) in self.queue.iter().enumerate().rev() {
-			if o == &op {
-				self.queue.remove(i);
-				return Ok(());
-			}
-		}
-		warn!("could not ack op {:?} from {:?}", op, self.queue);
-		Err(OTError)
-	}
-
-	pub fn process(&mut self, mut op: OperationSeq) -> Result<String, OTError> {
-		for o in self.queue.iter_mut() {
-			(op, *o) = op.transform(o)?;
-		}
-		self.content = op.apply(&self.content)?;
-		Ok(self.content.clone())
-	}
-}
-
-
-pub struct AsyncFactory {
-	run: watch::Sender<bool>,
-	ops: mpsc::Sender<OpMsg>,
-	#[allow(unused)] // TODO is this necessary?
-	content: watch::Receiver<String>,
-}
-
-impl Drop for AsyncFactory {
-	fn drop(&mut self) {
-		self.run.send(false).unwrap_or(());
-	}
-}
-
-impl AsyncFactory {
-	pub fn new(init: Option<String>) -> Self {
-		let (run_tx, run_rx) = watch::channel(true);
-		let (ops_tx, ops_rx) = mpsc::channel(64); // TODO hardcoded size
-		let (txt_tx, txt_rx) = watch::channel("".into());
-
-		let worker = AsyncFactoryWorker {
-			factory: OperationFactory::new(init),
-			ops: ops_rx,
-			run: run_rx,
-			content: txt_tx,
-		};
-
-		tokio::spawn(async move { worker.work().await });
-
-		AsyncFactory { run: run_tx, ops: ops_tx, content: txt_rx }
-	}
-
-	pub async fn insert(&self, txt: String, pos: u64) -> Result<OperationSeq, OTError> {
-		let (tx, rx) = oneshot::channel();
-		self.ops.send(OpMsg::Exec(OpWrapper::Insert(txt, pos), tx)).await.map_err(|_| OTError)?;
-		rx.await.map_err(|_| OTError)?
-	}
-
-	pub async fn delete(&self, pos: u64, count: u64) -> Result<OperationSeq, OTError> {
-		let (tx, rx) = oneshot::channel();
-		self.ops.send(OpMsg::Exec(OpWrapper::Delete(pos, count), tx)).await.map_err(|_| OTError)?;
-		rx.await.map_err(|_| OTError)?
-	}
-
-	pub async fn cancel(&self, pos: u64, count: u64) -> Result<OperationSeq, OTError> {
-		let (tx, rx) = oneshot::channel();
-		self.ops.send(OpMsg::Exec(OpWrapper::Cancel(pos, count), tx)).await.map_err(|_| OTError)?;
-		rx.await.map_err(|_| OTError)?
-	}
-
-	pub async fn replace(&self, txt: String) -> Result<OperationSeq, OTError> {
-		let (tx, rx) = oneshot::channel();
-		self.ops.send(OpMsg::Exec(OpWrapper::Replace(txt), tx)).await.map_err(|_| OTError)?;
-		rx.await.map_err(|_| OTError)?
-	}
-
-	pub async fn process(&self, opseq: OperationSeq) -> Result<String, OTError> {
-		let (tx, rx) = oneshot::channel();
-		self.ops.send(OpMsg::Process(opseq, tx)).await.map_err(|_| OTError)?;
-		rx.await.map_err(|_| OTError)?
-	}
-
-	pub async fn ack(&self, opseq: OperationSeq) -> Result<(), OTError> {
-		let (tx, rx) = oneshot::channel();
-		self.ops.send(OpMsg::Ack(opseq, tx)).await.map_err(|_| OTError)?;
-		rx.await.map_err(|_| OTError)?
-	}
-}
-
-
-#[derive(Debug)]
-enum OpMsg {
-	Exec(OpWrapper, oneshot::Sender<Result<OperationSeq, OTError>>),
-	Process(OperationSeq, oneshot::Sender<Result<String, OTError>>),
-	Ack(OperationSeq, oneshot::Sender<Result<(), OTError>>),
-}
-
-#[derive(Debug)]
-enum OpWrapper {
-	Insert(String, u64),
-	Delete(u64, u64),
-	Cancel(u64, u64),
-	Replace(String),
-}
-
-struct AsyncFactoryWorker {
-	factory: OperationFactory,
-	ops: mpsc::Receiver<OpMsg>,
-	run: watch::Receiver<bool>,
-	content: watch::Sender<String>
-}
-
-impl AsyncFactoryWorker {
-	async fn work(mut self) {
-		while *self.run.borrow() {
-			tokio::select! { // periodically check run so that we stop cleanly
-
-				recv = self.ops.recv() => {
-					match recv {
-						Some(msg) => {
-							match msg {
-								OpMsg::Exec(op, tx) => tx.send(self.exec(op)).unwrap_or(()),
-								OpMsg::Process(opseq, tx) => tx.send(self.factory.process(opseq)).unwrap_or(()),
-								OpMsg::Ack(opseq, tx) => tx.send(self.factory.ack(opseq)).unwrap_or(()),
-							}
-							if let Err(e) = self.content.send(self.factory.content()) {
-								error!("error updating content: {}", e);
-								break;
-							}
-						},
-						None => break,
-					}
-				},
-
-				_ = tokio::time::sleep(std::time::Duration::from_secs(1)) => {},
-
-			};
-		}
-	}
-
-	fn exec(&mut self, op: OpWrapper) -> Result<OperationSeq, OTError> {
-		match op {
-			OpWrapper::Insert(txt, pos) => Ok(self.factory.insert(&txt, pos)?),
-			OpWrapper::Delete(pos, count) => Ok(self.factory.delete(pos, count)?),
-			OpWrapper::Cancel(pos, count) => Ok(self.factory.cancel(pos, count)?),
-			OpWrapper::Replace(txt) => Ok(self.factory.replace(&txt)?),
-		}
-	}
-}