feat: propagate range of buffer affected by change

added some const functions to calculate leading and tailing noops, made
apply() and process() return Range<u64>. actors implementation is still
awful but will do them properly in the future

src/client/nvim/main.rs

@@ -147,7 +147,8 @@ impl Handler for NeovimHandler {
 							Ok(()) => {
 								tokio::spawn(async move {
 									loop {
-										_controller.wait().await;
+										let _span = _controller.wait().await;
+										// TODO only change lines affected!
 										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);

src/lib/client.rs

@@ -24,10 +24,6 @@ impl From::<BufferClient<Channel>> for CodempClient {
 }
 
 impl CodempClient {
-	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, content,
@@ -90,9 +86,7 @@ impl CodempClient {
 						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
-							}
+							Ok(_range) => { } // user gets this range by awaiting wait() so we can drop it here
 						}
 					},
 				}

src/lib/operation/mod.rs

@@ -1,5 +1,27 @@
 pub mod factory;
 pub mod processor;
 
+use std::ops::Range;
+
+use operational_transform::{Operation, OperationSeq};
 pub use processor::{OperationController, OperationProcessor};
 pub use factory::OperationFactory;
+
+pub const fn leading_noop(seq: &[Operation]) -> u64 { count_noop(seq.first()) }
+pub const fn tailing_noop(seq: &[Operation]) -> u64 { count_noop(seq.last())  }
+
+const fn count_noop(op: Option<&Operation>) -> u64 {
+	match op {
+		None => 0,
+		Some(op) => match op {
+			Operation::Retain(n) => *n,
+			_ => 0,
+		}
+	}
+}
+
+pub fn op_effective_range(op: &OperationSeq) -> Range<u64> {
+	let first = leading_noop(op.ops());
+	let last = op.base_len() as u64 - tailing_noop(op.ops());
+	first..last
+}

src/lib/operation/processor.rs

@@ -1,4 +1,4 @@
-use std::{sync::Mutex, collections::VecDeque};
+use std::{sync::Mutex, collections::VecDeque, ops::Range};
 
 use operational_transform::{OperationSeq, OTError};
 use tokio::sync::watch;
@@ -6,15 +6,17 @@ use tracing::warn;
 
 use crate::operation::factory::OperationFactory;
 
+use super::op_effective_range;
+
 
 #[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 apply(&self, op: OperationSeq) -> Result<Range<u64>, OTError>;
+	async fn process(&self, op: OperationSeq) -> Result<Range<u64>, OTError>;
 
 	async fn poll(&self) -> Option<OperationSeq>;
 	async fn ack(&self)  -> Option<OperationSeq>;
-	async fn wait(&self);
+	async fn wait(&self) -> Range<u64>;
 }
 
 
@@ -23,14 +25,14 @@ pub struct OperationController {
 	queue: Mutex<VecDeque<OperationSeq>>,
 	last: Mutex<watch::Receiver<OperationSeq>>,
 	notifier: watch::Sender<OperationSeq>,
-	changed: Mutex<watch::Receiver<()>>,
-	changed_notifier: watch::Sender<()>,
+	changed: Mutex<watch::Receiver<Range<u64>>>,
+	changed_notifier: watch::Sender<Range<u64>>,
 }
 
 impl OperationController {
 	pub fn new(content: String) -> Self {
 		let (tx, rx) = watch::channel(OperationSeq::default());
-		let (done, wait) = watch::channel(());
+		let (done, wait) = watch::channel(0..0);
 		OperationController {
 			text: Mutex::new(content),
 			queue: Mutex::new(VecDeque::new()),
@@ -60,32 +62,35 @@ fn ignore_and_log<T, E : std::fmt::Display>(x: Result<T, E>, msg: &str) {
 
 #[tonic::async_trait]
 impl OperationProcessor for OperationController {
-	async fn apply(&self, op: OperationSeq) -> Result<String, OTError> {
+	async fn apply(&self, op: OperationSeq) -> Result<Range<u64>, OTError> {
 		let txt = self.content();
 		let res = op.apply(&txt)?;
 		*self.text.lock().unwrap() = res.clone();
 		self.queue.lock().unwrap().push_back(op.clone());
-		ignore_and_log(self.notifier.send(op), "notifying of applied change");
-		Ok(res)
+		ignore_and_log(self.notifier.send(op.clone()), "notifying of applied change");
+		Ok(op_effective_range(&op))
 	}
 
-	async fn wait(&self) {
+	async fn wait(&self) -> Range<u64> {
 		let mut blocker = self.changed.lock().unwrap().clone();
 		// TODO less jank way
 		ignore_and_log(blocker.changed().await, "waiting for changed content #1");
 		ignore_and_log(blocker.changed().await, "waiting for changed content #2");
+		let span = blocker.borrow().clone();
+		span
 	}
 
-	async fn process(&self, mut op: OperationSeq) -> Result<String, OTError> {
+	async fn process(&self, mut op: OperationSeq) -> Result<Range<u64>, 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)?;
+		let span = op_effective_range(&op);
 		*self.text.lock().unwrap() = res.clone();
-		ignore_and_log(self.changed_notifier.send(()), "notifying of changed content");
-		Ok(res)
+		ignore_and_log(self.changed_notifier.send(span.clone()), "notifying of changed content");
+		Ok(span)
 	}
 
 	async fn poll(&self) -> Option<OperationSeq> {