Add the ability to prefetch CD-ROM chunks

Sends them to the service worker using the same mechanism as regular disk images.

Updates #382

Author: mihaip

src/Browser.tsx

@@ -322,6 +322,7 @@ function DiskContents({disk, onRun}: DiskContentsProps) {
             libraryDownloadURLs: [],
             machine: disk.preferredMachine,
             cdromURLs: [],
+            cdromPrefetchChunks: [],
             diskFiles: [],
         } satisfies RunDef;
         const inNewWindow =

src/Custom.tsx

@@ -33,6 +33,7 @@ export function Custom({
                   screenSize: "auto",
                   disks: [defaultDisk],
                   cdromURLs: [],
+                  cdromPrefetchChunks: [],
                   includeInfiniteHD: true,
                   includeSavedHD: canSaveDisks(),
                   includeLibrary: true,

src/Embed.tsx

@@ -38,6 +38,7 @@ export function Embed({
         screenSize: "auto",
         disks: [defaultDisk],
         cdromURLs: [],
+        cdromPrefetchChunks: [],
         includeInfiniteHD: true,
         includeSavedHD: false,
         includeLibrary: false,

src/RunDefMac.tsx

@@ -18,14 +18,23 @@ export default function RunDefMac({runDef, onDone}: RunDefMacProps) {
     );
     useEffect(() => {
         if (runDef.cdromURLs.length) {
-            Promise.all(runDef.cdromURLs.map(getCDROMInfo))
+            Promise.all(
+                runDef.cdromURLs.map(async (url, i) => {
+                    const info = await getCDROMInfo(url);
+                    const prefetchChunks = runDef.cdromPrefetchChunks[i];
+                    if (prefetchChunks?.length > 0) {
+                        return {...info, prefetchChunks};
+                    }
+                    return info;
+                })
+            )
                 .then(setCDROMs)
                 .catch(error => {
                     setCDROMErrorText(`Could not load the CD-ROM: ${error}`);
                     setCDROMs([]);
                 });
         }
-    }, [runDef.cdromURLs]);
+    }, [runDef.cdromURLs, runDef.cdromPrefetchChunks]);
     const disks = Array.from(new Set(runDef.disks));
     disks.forEach(disk => disk.generatedSpec()); // Prefetch the disk definition
     return cdroms ? (

src/emulator/emulator-common.ts

@@ -121,6 +121,9 @@ export function generateNextChunkUrl(
     url: string,
     specs: EmulatorChunkedFileSpec[]
 ): string | undefined {
+    if (url.includes("CD-ROM")) {
+        return undefined;
+    }
     const match = url.match(/.*\/([0-9a-f]+)\.chunk#(\d+)$/);
     if (!match) {
         console.warn(`Could not parse chunk URL ${url}`);
@@ -509,6 +512,38 @@ export type EmulatorCDROM = {
     platform?: "Macintosh" | "NeXT";
     fetchClientSide?: boolean;
     mountReadWrite?: boolean;
+    prefetchChunks?: number[];
 };
 
 export type EmulatorCDROMLibrary = {[path: string]: EmulatorCDROM};
+
+export function generateChunkedFileSpecForCDROM(
+    cdrom: EmulatorCDROM
+): EmulatorChunkedFileSpec {
+    const CHUNK_SIZE = 128 * 1024;
+
+    const {name, fileSize: totalSize} = cdrom;
+    let chunkStart = 0;
+    const chunks: string[] = [];
+    while (chunkStart < totalSize) {
+        const chunkEnd = Math.min(chunkStart + CHUNK_SIZE, totalSize);
+        chunks.push(`${chunkStart}-${chunkEnd}`);
+        chunkStart = chunkEnd;
+    }
+    // Minimal metadata for workers-site/cd-rom.ts to reconstruct
+    const encoded = btoa(
+        JSON.stringify({
+            srcUrl: cdrom.srcUrl,
+            totalSize,
+        })
+    );
+
+    return {
+        name,
+        baseUrl: `/CD-ROM/${encoded}`,
+        totalSize,
+        chunks,
+        chunkSize: CHUNK_SIZE,
+        prefetchChunks: cdrom.prefetchChunks ?? [0],
+    };
+}

src/emulator/emulator-ui.ts

@@ -6,6 +6,7 @@ import {
     type EmulatorWorkerConfig,
     type EmulatorWorkerVideoBlit,
     type EmulatorMouseEvent,
+    generateChunkedFileSpecForCDROM,
 } from "./emulator-common";
 import {
     emulatorUsesPlaceholderDisks,
@@ -462,7 +463,18 @@ export class Emulator {
 
         const serviceWorkerAvailable = await this.#serviceWorkerReady;
         if (serviceWorkerAvailable) {
-            for (const spec of config.disks.concat(config.delayedDisks ?? [])) {
+            const specs = [
+                ...config.disks,
+                ...(config.delayedDisks ?? []),
+                ...config.cdroms
+                    .filter(
+                        cdrom =>
+                            !cdrom.fetchClientSide &&
+                            cdrom.prefetchChunks?.length
+                    )
+                    .map(generateChunkedFileSpecForCDROM),
+            ];
+            for (const spec of specs) {
                 this.#serviceWorker!.postMessage({
                     type: "init-disk-cache",
                     spec,
@@ -788,7 +800,6 @@ export class Emulator {
 
     #getAdbKeyCode(code: string): number | undefined {
         if (this.#delegate?.emulatorSettings?.(this).swapControlAndCommand) {
-            console.log("swapping control and command keys");
             if (code.startsWith("Control")) {
                 code = "Meta" + code.slice("Control".length);
             } else if (code.startsWith("Meta")) {

src/emulator/emulator-worker-cdrom-disk.ts

@@ -1,13 +1,14 @@
-import {type EmulatorCDROM} from "./emulator-common";
+import {
+    type EmulatorCDROM,
+    generateChunkedFileSpecForCDROM,
+} from "./emulator-common";
 import {
     EmulatorWorkerChunkedDisk,
     type EmulatorWorkerChunkedDiskDelegate,
 } from "./emulator-worker-chunked-disk";
 import {type EmulatorWorkerDisk} from "./emulator-worker-disks";
 import {EmulatorWorkerUploadDisk} from "./emulator-worker-upload-disk";
 
-const CHUNK_SIZE = 128 * 1024;
-
 export function createEmulatorWorkerCDROMDisk(
     cdrom: EmulatorCDROM,
     delegate: EmulatorWorkerChunkedDiskDelegate
@@ -22,29 +23,9 @@ export function createEmulatorWorkerCDROMDisk(
             delegate
         );
     }
-    const {name, fileSize: totalSize} = cdrom;
-    let chunkStart = 0;
-    const chunks: string[] = [];
-    while (chunkStart < totalSize) {
-        const chunkEnd = Math.min(chunkStart + CHUNK_SIZE, totalSize);
-        chunks.push(`${chunkStart}-${chunkEnd}`);
-        chunkStart = chunkEnd;
-    }
-    // Minimal metadata for workers-site/cd-rom.ts to reconstruct
-    const encoded = btoa(
-        JSON.stringify({
-            srcUrl: cdrom.srcUrl,
-            totalSize,
-        })
-    );
-    const spec = {
-        name,
-        baseUrl: `/CD-ROM/${encoded}`,
-        totalSize,
-        chunks,
-        chunkSize: CHUNK_SIZE,
-        prefetchChunks: [0],
-    };
+
+    const spec = generateChunkedFileSpecForCDROM(cdrom);
+
     let disk: EmulatorWorkerDisk = new EmulatorWorkerChunkedDisk(
         spec,
         delegate

src/emulator/emulator-worker-disks.ts

@@ -36,6 +36,9 @@ export class EmulatorWorkerDisksApi {
                 this.#removableDisks.push(new EmulatorRemovableDisk());
             }
         }
+        // Expose the validation function globally in case the user wants to
+        // re-validate prefetched chunks even later.
+        (globalThis as any)["validateDisks"] = this.validate.bind(this);
     }
 
     isMediaPresent(diskId: DiskId): boolean {

src/run-def.ts

@@ -28,6 +28,7 @@ export type RunDef = {
     disks: SystemDiskDef[];
     diskFiles: DiskFile[];
     cdromURLs: string[];
+    cdromPrefetchChunks: number[][];
     includeInfiniteHD: boolean;
     includeSavedHD: boolean;
     includeLibrary: boolean;
@@ -149,6 +150,16 @@ export function runDefFromUrl(urlString: string): RunDef | undefined {
         ...searchParams.getAll("cdrom"),
         ...searchParams.getAll("cdrom_url"),
     ];
+    const cdromPrefetchChunks: number[][] = [];
+    for (const cdromPrefetch of searchParams.getAll("cdrom_prefetch")) {
+        const chunks = cdromPrefetch
+            .split(",")
+            .map(s => parseInt(s))
+            .filter(n => !isNaN(n));
+        if (chunks.length > 0) {
+            cdromPrefetchChunks.push(chunks);
+        }
+    }
 
     let ethernetProvider;
     const appleTalkZoneName = searchParams.get("appleTalk");
@@ -197,6 +208,7 @@ export function runDefFromUrl(urlString: string): RunDef | undefined {
         screenScale,
         ethernetProvider,
         cdromURLs,
+        cdromPrefetchChunks,
         diskFiles: [],
         customDate,
         debugFallback,
@@ -250,6 +262,9 @@ export function runDefToUrl(runDef: RunDef, toEmbed: boolean = false): string {
     for (const cdromURL of runDef.cdromURLs) {
         url.searchParams.append("cdrom", cdromURL);
     }
+    for (const cdromPrefetch of runDef.cdromPrefetchChunks) {
+        url.searchParams.append("cdrom_prefetch", cdromPrefetch.join(","));
+    }
 
     if (
         toEmbed ||