xP: implement buffer line leakage

Rather than on redisplay, these get cleared on reconnect.

xC-proto

@@ -60,6 +60,7 @@ struct EventMessage {
 		string buffer_name;
 	case BUFFER_LINE:
 		string buffer_name;
+		bool leak_to_active;
 		bool is_unimportant;
 		bool is_highlight;
 		enum Rendition {

xC.c

@@ -3097,7 +3097,7 @@ relay_prepare_buffer_activate (struct app_context *ctx, struct buffer *buffer)
 
 static void
 relay_prepare_buffer_line (struct app_context *ctx, struct buffer *buffer,
-	struct buffer_line *line)
+	struct buffer_line *line, bool leak_to_active)
 {
 	struct relay_event_message *m = relay_prepare (ctx);
 	struct relay_event_data_buffer_line *e = &m->data.buffer_line;
@@ -3107,6 +3107,7 @@ relay_prepare_buffer_line (struct app_context *ctx, struct buffer *buffer,
 	e->is_highlight = !!(line->flags & BUFFER_LINE_HIGHLIGHT);
 	e->rendition = 1 + line->r;
 	e->when = line->when * 1000;
+	e->leak_to_active = leak_to_active;
 
 	size_t len = 0;
 	for (size_t i = 0; line->items[i].type; i++)
@@ -4588,9 +4589,6 @@ log_formatter (struct app_context *ctx, struct buffer *buffer,
 	if (buffer->log_file)
 		buffer_line_write_to_log (ctx, line, buffer->log_file);
 
-	relay_prepare_buffer_line (ctx, buffer, line);
-	relay_broadcast (ctx);
-
 	bool unseen_pm = buffer->type == BUFFER_PM
 		&& buffer != ctx->current_buffer
 		&& !(flags & BUFFER_LINE_UNIMPORTANT);
@@ -4607,6 +4605,10 @@ log_formatter (struct app_context *ctx, struct buffer *buffer,
 		&& buffer == ctx->current_buffer->server->buffer))
 		can_leak = true;
 
+	relay_prepare_buffer_line
+		(ctx, buffer, line, can_leak && !ctx->isolate_buffers);
+	relay_broadcast (ctx);
+
 	bool displayed = true;
 	if (ctx->terminal_suspended > 0)
 		// Another process is using the terminal
@@ -5011,7 +5013,7 @@ buffer_merge (struct app_context *ctx,
 	// And since there is no log_*() call, send them to relays manually
 	LIST_FOR_EACH (struct buffer_line, line, start)
 	{
-		relay_prepare_buffer_line (ctx, buffer, line);
+		relay_prepare_buffer_line (ctx, buffer, line, false);
 		relay_broadcast (ctx);
 	}
 
@@ -15166,7 +15168,7 @@ client_resync (struct client *c)
 
 		LIST_FOR_EACH (struct buffer_line, line, buffer->lines)
 		{
-			relay_prepare_buffer_line (c->ctx, buffer, line);
+			relay_prepare_buffer_line (c->ctx, buffer, line, false);
 			relay_send (c);
 		}
 	}

xP/public/xP.css

@@ -63,6 +63,9 @@ body {
 	overflow-y: auto;
 }
 
+.leaked {
+	opacity: 50%;
+}
 .date {
 	padding: .3rem;
 	grid-column: span 2;

xP/public/xP.js

@@ -195,10 +195,12 @@ rpc.addEventListener('BufferActivate', event => {
 })
 
 rpc.addEventListener('BufferLine', event => {
-	let e = event.detail, b = buffers.get(e.bufferName)
+	let e = event.detail, b = buffers.get(e.bufferName),
-	if (b === undefined)
+		line = {when: e.when, rendition: e.rendition, items: e.items}
-		return
+	if (b !== undefined)
-	b.lines.push({when: e.when, rendition: e.rendition, items: e.items})
+		b.lines.push({...line})
+	if (e.leakToActive && (b = buffers.get(bufferCurrent)) !== undefined)
+		b.lines.push({leaked: true, ...line})
 })
 
 rpc.addEventListener('BufferClear', event => {
@@ -327,7 +329,7 @@ let Content = {
 				classes.add(c)
 		}
 		let fg = -1, bg = -1, inverse = false
-		return m('.content', {}, [mark, line.items.flatMap(item => {
+		return m('.content', vnode.attrs, [mark, line.items.flatMap(item => {
 			switch (item.kind) {
 			case 'Text':
 				return Content.linkify(item.text, {
@@ -393,8 +395,12 @@ let Buffer = {
 				lastDateMark = dateMark
 			}
 
-			lines.push(m('.time', {}, date.toLocaleTimeString()))
+			let attrs = {}
-			lines.push(m(Content, {}, line))
+			if (line.leaked)
+				attrs.class = 'leaked'
+
+			lines.push(m('.time', {...attrs}, date.toLocaleTimeString()))
+			lines.push(m(Content, {...attrs}, line))
 		})
 		return m('.buffer', {}, lines)
 	},