abstract jpeg encoding away from "WSServer"

Additionally make thumbnail encoding threadpooled as well, just so it (probably) doesn't block as much.

cvmts/src/JPEGEncoder.ts

@@ -0,0 +1,59 @@
+import path from 'node:path';
+import Piscina from 'piscina';
+
+import { Size, Rect } from '@cvmts/shared';
+
+const kMaxJpegThreads = 4;
+const kIdleTimeout = 25000;
+
+// Thread pool for doing JPEG encoding for rects.
+const TheJpegEncoderPool = new Piscina({
+	filename: path.join(import.meta.dirname + '/JPEGEncoderWorker.js'),
+	idleTimeout: kIdleTimeout,
+	maxThreads: kMaxJpegThreads
+});
+
+const TheThumbnailEncoderPool = new Piscina({
+	filename: path.join(import.meta.dirname + '/ThumbnailJPEGEncoderWorker.js'),
+	idleTimeout: kIdleTimeout,
+	maxThreads: kMaxJpegThreads
+});
+
+// A good balance. TODO: Configurable?
+let gJpegQuality = 35;
+
+export class JPEGEncoder {
+
+	static SetQuality(quality: number) {
+		gJpegQuality = quality;
+	}
+
+	static async EncodeJpeg(canvas: Buffer, displaySize: Size, rect: Rect): Promise<Buffer> {
+		let offset = (rect.y * displaySize.width + rect.x) * 4;
+
+		let res = await TheJpegEncoderPool.run({
+			buffer: canvas.subarray(offset),
+			width: rect.width,
+			height: rect.height,
+			stride: displaySize.width,
+			quality: gJpegQuality
+		});
+
+		// TODO: There's probably (definitely) a better way to fix this
+		if (res == undefined) return Buffer.from([]);
+
+		// have to manually turn it back into a buffer because
+		// Piscina for some reason turns it into a Uint8Array
+		return Buffer.from(res);
+	}
+
+	static async EncodeThumbnail(buffer: Buffer, size: Size) : Promise<Buffer>  {
+		let res = await TheThumbnailEncoderPool.run({
+			buffer: buffer,
+			size: size,
+			quality: gJpegQuality
+		});
+
+		return Buffer.from(res)
+	}
+}

cvmts/src/JPEGEncoderWorker.ts

@@ -9,7 +9,7 @@ export default async (opts: any) => {
 			height: opts.height,
 			subsampling: jpegTurbo.SAMP_422,
 			stride: opts.stride,
-			quality: opts.quality
+			quality: opts.quality || 75
 		});
 
 		return Piscina.move(res);

cvmts/src/ThumbnailJPEGEncoderWorker.ts

@@ -0,0 +1,31 @@
+import { Size } from '@cvmts/shared';
+import Piscina from 'piscina';
+import sharp from 'sharp';
+
+const kThumbnailSize: Size = {
+	width: 400,
+	height: 300
+};
+
+// this returns appropiate Sharp options to deal with CVMTS raw framebuffers
+// (which are RGBA bitmaps, essentially. We probably should abstract that out but
+// that'd mean having to introduce that to rfb and oihwekjtgferklds;./tghnredsltg;erhds)
+function GetRawSharpOptions(size: Size): sharp.CreateRaw {
+	return {
+		width: size.width,
+		height: size.height,
+		channels: 4
+	};
+}
+
+export default async (opts: any) => {
+	let out = await sharp(opts.buffer, { raw: GetRawSharpOptions(opts.size) })
+		.resize(kThumbnailSize.width, kThumbnailSize.height, { fit: 'fill' })
+		.jpeg({
+			quality: opts.quality || 75
+		})
+		.toFormat('jpeg')
+		.toBuffer();
+
+	return Piscina.move(out);
+};

cvmts/src/WSServer.ts

@@ -17,8 +17,7 @@ import path from 'node:path';
 import AuthManager from './AuthManager.js';
 import { Size, Rect, Logger } from '@cvmts/shared';
 
-import sharp from 'sharp';
+import { JPEGEncoder } from './JPEGEncoder.js';
-import Piscina from 'piscina';
 
 // Instead of strange hacks we can just use nodejs provided
 // import.meta properties, which have existed since LTS if not before
@@ -37,43 +36,8 @@ type VoteTally = {
 	no: number;
 };
 
-// A good balance. TODO: Configurable?
-const kJpegQuality = 35;
 
-// this returns appropiate Sharp options to deal with the framebuffer
-function GetRawSharpOptions(size: Size): sharp.CreateRaw {
-	return {
-		width: size.width,
-		height: size.height,
-		channels: 4
-	};
-}
 
-// Thread pool for doing JPEG encoding for rects.
-const TheJpegEncoderPool = new Piscina({
-	filename: path.join(import.meta.dirname + '/JPEGEncoderWorker.js'),
-	minThreads: 4,
-	maxThreads: 4
-});
-
-async function EncodeJpeg(canvas: Buffer, displaySize: Size, rect: Rect): Promise<Buffer> {
-	let offset = (rect.y * displaySize.width + rect.x) * 4;
-
-	let res = await TheJpegEncoderPool.run({
-		buffer: canvas.subarray(offset),
-		width: rect.width,
-		height: rect.height,
-		stride: displaySize.width,
-		quality: kJpegQuality
-	});
-
-	// TODO: There's probably (definitely) a better way to fix this
-	if (res == undefined) return Buffer.from([]);
-
-	// have to manually turn it back into a buffer because
-	// Piscina for some reason turns it into a Uint8Array
-	return Buffer.from(res);
-}
 
 export default class WSServer {
 	private Config: IConfig;
@@ -930,24 +894,17 @@ export default class WSServer {
 		let display = this.VM.GetDisplay();
 		let displaySize = display.Size();
 
-		let encoded = await EncodeJpeg(display.Buffer(), displaySize, rect);
+		let encoded = await JPEGEncoder.EncodeJpeg(display.Buffer(), displaySize, rect);
 
 		return encoded.toString('base64');
 	}
 
-	getThumbnail(): Promise<string> {
+	async getThumbnail(): Promise<string> {
-		return new Promise(async (res, rej) => {
 		let display = this.VM.GetDisplay();
-			if (display == null) return;
+		if (!display.Connected()) throw new Error('VM display is not connected');
 
-			// TODO: pass custom options to Sharp.resize() probably
+		let buf = await JPEGEncoder.EncodeThumbnail(display.Buffer(), display.Size());
-			let out = await sharp(display.Buffer(), { raw: GetRawSharpOptions(display.Size()) })
+		return buf.toString('base64');
-				.resize(400, 300, { fit: 'fill' })
-				.toFormat('jpeg')
-				.toBuffer();
-
-			res(out.toString('base64'));
-		});
 	}
 
 	startVote() {

qemu/src/QemuDisplay.ts

@@ -116,6 +116,10 @@ export class QemuDisplay extends EventEmitter {
 		this.displayVnc.disconnect();
 	}
 
+	Connected() {
+		return this.displayVnc.connected;
+	}
+
 	Buffer(): Buffer {
 		return this.displayVnc.fb;
 	}