WIP: Make the relay acknowledge received commands

xP now slightly throttles activity notifications,
and indicates when there are unacknowledged commands.

Relay events have been reordered to improve forward compatibility.

As can be observed, even the smallest protocol change has
great consequences.

WIP:
 - xC: fix connection killing

1 files changed, 37 insertions, 9 deletions

diff --git a/xP/public/xP.js b/xP/public/xP.js
index 6035db3..33d7d2a 100644
--- a/xP/public/xP.js
+++ b/xP/public/xP.js
@@ -1,4 +1,4 @@
-// Copyright (c) 2022 - 2024, Přemysl Eric Janouch <p@janouch.name>
+// Copyright (c) 2022 - 2025, Přemysl Eric Janouch <p@janouch.name>
 // SPDX-License-Identifier: 0BSD
 import * as Relay from './proto.js'
 
@@ -67,18 +67,19 @@ class RelayRPC extends EventTarget {
 
 	_processOne(message) {
 		let e = message.data
+		let p
 		switch (e.event) {
 		case Relay.Event.Error:
-			if (this.promised[e.commandSeq] !== undefined)
-				this.promised[e.commandSeq].reject(e.error)
-			else
+			if ((p = this.promised[e.commandSeq]) === undefined)
 				console.error(`Unawaited error: ${e.error}`)
+			else if (p !== true)
+				p.reject(e.error)
 			break
 		case Relay.Event.Response:
-			if (this.promised[e.commandSeq] !== undefined)
-				this.promised[e.commandSeq].resolve(e.data)
-			else
+			if ((p = this.promised[e.commandSeq]) === undefined)
 				console.error("Unawaited response")
+			else if (p !== true)
+				p.resolve(e.data)
 			break
 		default:
 			e.eventSeq = message.eventSeq
@@ -95,6 +96,13 @@ class RelayRPC extends EventTarget {
 			this.promised[seq].reject("No response")
 			delete this.promised[seq]
 		}
+		m.redraw()
+	}
+
+	get busy() {
+		for (const seq in this.promised)
+			return true
+		return false
 	}
 
 	send(params) {
@@ -110,6 +118,9 @@ class RelayRPC extends EventTarget {
 
 		this.ws.send(JSON.stringify({commandSeq: seq, data: params}))
 
+		this.promised[seq] = true
+		m.redraw()
+
 		// Automagically detect if we want a result.
 		let data = undefined
 		const promise = new Promise(
@@ -191,6 +202,17 @@ let bufferAutoscroll = true
 
 let servers = new Map()
 
+let lastActive = undefined
+
+function notifyActive() {
+	// Reduce unnecessary traffic.
+	const now = Date.now()
+	if (lastActive === undefined || (now - lastActive >= 5000)) {
+		lastActive = now
+		rpc.send({command: 'Active'})
+	}
+}
+
 function bufferResetStats(b) {
 	b.newMessages = 0
 	b.newUnimportantMessages = 0
@@ -998,7 +1020,7 @@ let Input = {
 
 	onKeyDown: event => {
 		// TODO: And perhaps on other actions, too.
-		rpc.send({command: 'Active'})
+		notifyActive()
 
 		let b = buffers.get(bufferCurrent)
 		if (b === undefined || event.isComposing)
@@ -1103,7 +1125,13 @@ let Main = {
 
 		return m('.xP', {}, [
 			overlay,
-			m('.title', {}, [m('b', {}, `xP`), m(Topic)]),
+			m('.title', {}, [
+				m('span', [
+					rpc.busy ? '⋯ ' : undefined,
+					m('b', {}, `xP`),
+				]),
+				m(Topic),
+			]),
 			m('.middle', {}, [m(BufferList), m(BufferContainer)]),
 			m(Status),
 			m('.input', {}, [m(Prompt), m(Input)]),