feat: very crude cursor implementation

proto/buffer.proto

@@ -6,6 +6,8 @@ service Buffer {
 	rpc Edit   (OperationRequest) returns (BufferResponse);
 	rpc Create (BufferPayload)    returns (BufferResponse);
 	rpc Sync   (BufferPayload)    returns (BufferResponse);
+	rpc Cursor (CursorMov)        returns (BufferResponse);
+	rpc Listen (BufferPayload)    returns (stream CursorMov);
 }
 
 message RawOp {
@@ -13,6 +15,13 @@ message RawOp {
 	string user = 2;
 }
 
+message CursorMov {
+	string user = 1;
+	string path = 2;
+	int64 row = 3;
+	int64 col = 4;
+}
+
 message OperationRequest {
 	string path  = 1;
 	string hash  = 2;

src/client/nvim/codemp.lua

@@ -4,8 +4,10 @@ local M = {}
 M.jobid = nil
 M.create = function(path, content) return vim.rpcrequest(M.jobid, "create", path, content) end
 M.insert = function(path, txt, pos) return vim.rpcrequest(M.jobid, "insert", path, txt, pos) end
+M.cursor = function(path, row, col) return vim.rpcrequest(M.jobid, "cursor", path, row, col) end
 M.delete = function(path, pos, count) return vim.rpcrequest(M.jobid, "delete", path, pos, count) end
 M.attach = function(path) return vim.rpcrequest(M.jobid, "attach", path) end
+M.listen = function(path) return vim.rpcrequest(M.jobid, "listen", path) end
 M.detach = function(path) return vim.rpcrequest(M.jobid, "detach", path) end
 
 local function cursor_offset()
@@ -24,6 +26,17 @@ local function hook_callbacks(path, buffer)
 			group = codemp_autocmds,
 		}
 	)
+	vim.api.nvim_create_autocmd(
+		{ "CursorMoved" },
+		{
+			callback = function(_)
+				local cursor = vim.api.nvim_win_get_cursor(0)
+				M.cursor(path, cursor[1], cursor[2])
+			end,
+			buffer = buffer,
+			group = codemp_autocmds,
+		}
+	)
 	vim.keymap.set('i', '<BS>', function() M.delete(path, cursor_offset(), 1) return '<BS>' end, {expr = true, buffer = buffer})
 	vim.keymap.set('i', '<Del>', function() M.delete(path, cursor_offset() + 1, 1) return '<Del>' end, {expr = true, buffer = buffer})
 	vim.keymap.set('i', '<CR>', function() M.insert(path, "\n", cursor_offset()) return '<CR>'end, {expr = true, buffer = buffer})
@@ -76,6 +89,7 @@ vim.api.nvim_create_user_command('Share',
 		M.create(path, vim.fn.join(lines, "\n"))
 		hook_callbacks(path, bufnr)
 		M.attach(path)
+		M.listen(path)
 	end,
 { nargs=1 })
 
@@ -85,6 +99,7 @@ vim.api.nvim_create_user_command('Join',
 		local bufnr = vim.api.nvim_get_current_buf()
 		hook_callbacks(path, bufnr)
 		M.attach(path)
+		M.listen(path)
 	end,
 { nargs=1 })
 

src/client/nvim/main.rs

@@ -25,11 +25,11 @@ fn default_empty_str(args: &Vec<Value>, index: usize) -> String {
 	nullable_optional_str(args, index).unwrap_or("".into())
 }
 
-fn nullable_optional_number(args: &Vec<Value>, index: usize) -> Option<u64> {
-	Some(args.get(index)?.as_u64()?)
+fn nullable_optional_number(args: &Vec<Value>, index: usize) -> Option<i64> {
+	Some(args.get(index)?.as_i64()?)
 }
 
-fn default_zero_number(args: &Vec<Value>, index: usize) -> u64 {
+fn default_zero_number(args: &Vec<Value>, index: usize) -> i64 {
 	nullable_optional_number(args, index).unwrap_or(0)
 }
 
@@ -69,7 +69,7 @@ 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);
+				let pos = default_zero_number(&args, 2) as u64;
 				let mut c = self.client.clone();
 				info!("correctly parsed arguments: {} - {} - {}", path, txt, pos);
 				match c.insert(path, txt, pos).await {
@@ -89,8 +89,8 @@ impl Handler for NeovimHandler {
 					return Err(Value::from("not enough arguments"));
 				}
 				let path = default_empty_str(&args, 0);
-				let pos = default_zero_number(&args, 1);
-				let count = default_zero_number(&args, 2);
+				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 {
@@ -145,6 +145,53 @@ impl Handler for NeovimHandler {
 				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 as i64 - 1, cur.col as i64 - 1, cur.col as i64
+						).await {
+							error!("could not create highlight for cursor: {}", e);
+						}
+					});
+				}).await {
+					Ok(()) => Ok(Value::Nil),
+					Err(e) => Err(Value::from(format!("could not listen cursors: {}", e))),
+				}
+			},
+
+			"cursor" => {
+				if args.len() < 3 {
+					return Err(Value::from("not enough args"));
+				}
+				let path = default_empty_str(&args, 0);
+				let row = default_zero_number(&args, 1);
+				let col = default_zero_number(&args, 2);
+
+				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))),
+				}
+			},
+
 			_ => Err(Value::from("unimplemented")),
 		}
 	}

src/lib/client.rs

@@ -6,7 +6,7 @@ use uuid::Uuid;
 
 use crate::{
 	opfactory::AsyncFactory,
-	proto::{buffer_client::BufferClient, BufferPayload, OperationRequest, RawOp},
+	proto::{buffer_client::BufferClient, BufferPayload, OperationRequest, RawOp, CursorMov},
 	tonic::{transport::Channel, Status, Streaming},
 };
 
@@ -89,6 +89,32 @@ impl CodempClient {
 		}
 	}
 
+	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 {
+		let req = BufferPayload {
+			path,
+			content: None,
+			user: self.id.to_string(),
+		};
+		let mut stream = self.client.listen(req).await?.into_inner();
+		tokio::spawn(async move {
+			// TODO catch some errors
+			while let Ok(Some(x)) = stream.message().await {
+				callback(x)
+			}
+		});
+		Ok(())
+	}
+
 	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?;

src/lib/opfactory.rs

@@ -70,6 +70,7 @@ impl OperationFactory {
 pub struct AsyncFactory {
 	run: watch::Sender<bool>,
 	ops: mpsc::Sender<OpMsg>,
+	#[allow(unused)] // TODO is this necessary?
 	content: watch::Receiver<String>,
 }
 
@@ -123,9 +124,6 @@ impl AsyncFactory {
 }
 
 
-
-
-
 #[derive(Debug)]
 enum OpMsg {
 	Exec(OpWrapper, oneshot::Sender<Result<OperationSeq, OTError>>),

src/server/buffer/service.rs

@@ -1,16 +1,17 @@
 use std::{pin::Pin, sync::{Arc, RwLock}, collections::HashMap};
 
-use tokio::sync::mpsc;
+use tokio::sync::{mpsc, broadcast};
 use tonic::{Request, Response, Status};
 
 use tokio_stream::{Stream, wrappers::ReceiverStream}; // TODO example used this?
 
-use codemp::proto::{buffer_server::{Buffer, BufferServer}, RawOp, BufferPayload, BufferResponse, OperationRequest};
+use codemp::proto::{buffer_server::{Buffer, BufferServer}, RawOp, BufferPayload, BufferResponse, OperationRequest, CursorMov};
 use tracing::info;
 
 use super::actor::{BufferHandle, BufferStore};
 
 type OperationStream = Pin<Box<dyn Stream<Item = Result<RawOp, Status>> + Send>>;
+type CursorStream    = Pin<Box<dyn Stream<Item = Result<CursorMov, Status>> + Send>>;
 
 struct BufferMap {
 	store: HashMap<String, BufferHandle>,
@@ -33,11 +34,22 @@ impl BufferStore<String> for BufferMap {
 
 pub struct BufferService {
 	map: Arc<RwLock<BufferMap>>,
+	cursor: broadcast::Sender<CursorMov>,
+}
+
+impl BufferService {
+	fn get_buffer(&self, path: &String) -> Result<BufferHandle, Status> {
+		match self.map.read().unwrap().get(path) {
+			Some(buf) => Ok(buf.clone()),
+			None => Err(Status::not_found("no buffer for given path")),
+		}
+	}
 }
 
 #[tonic::async_trait]
 impl Buffer for BufferService {
 	type AttachStream = OperationStream;
+	type ListenStream = CursorStream;
 
 	async fn attach(&self, req: Request<BufferPayload>) -> Result<tonic::Response<OperationStream>, Status> {
 		let request = req.into_inner();
@@ -65,6 +77,33 @@ impl Buffer for BufferService {
 		}
 	}
 
+	async fn listen(&self, req: Request<BufferPayload>) -> Result<tonic::Response<CursorStream>, Status> {
+		let mut sub = self.cursor.subscribe();
+		let myself = req.into_inner().user;
+		let (tx, rx) = mpsc::channel(128);
+		tokio::spawn(async move {
+			loop {
+				match sub.recv().await {
+					Ok(v) => {
+						if v.user == myself { continue }
+						tx.send(Ok(v)).await.unwrap(); // TODO unnecessary channel?
+					}
+					Err(_e) => break,
+				}
+			}
+		});
+		let output_stream = ReceiverStream::new(rx);
+		info!("registered new subscriber to cursor updates");
+		Ok(Response::new(Box::pin(output_stream)))
+	}
+
+	async fn cursor(&self, req:Request<CursorMov>) -> Result<Response<BufferResponse>, Status> {
+		match self.cursor.send(req.into_inner()) {
+			Ok(_) => Ok(Response::new(BufferResponse { accepted: true, content: None})),
+			Err(e) => Err(Status::internal(format!("could not broadcast cursor update: {}", e))),
+		}
+	}
+
 	async fn edit(&self, req:Request<OperationRequest>) -> Result<Response<BufferResponse>, Status> {
 		let request = req.into_inner();
 		let tx = match self.map.read().unwrap().get(&request.path) {
@@ -106,8 +145,10 @@ impl Buffer for BufferService {
 
 impl BufferService {
 	pub fn new() -> BufferService {
+		let (cur_tx, _cur_rx) = broadcast::channel(64); // TODO hardcoded capacity
 		BufferService {
 			map: Arc::new(RwLock::new(HashMap::new().into())),
+			cursor: cur_tx,
 		}
 	}