From 26079d118865874bf4b8185e7858e54d81df4163 Mon Sep 17 00:00:00 2001
From: Misode <misoloo64@gmail.com>
Date: Wed, 6 Nov 2024 06:53:05 +0100
Subject: [PATCH] Sort overlay file systems based on prefix length

---
 src/app/services/FileSystem.ts | 17 ++++++++++-------
 src/app/services/Spyglass.ts   |  6 ++++--
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/src/app/services/FileSystem.ts b/src/app/services/FileSystem.ts
index d7bf6659..1a09966a 100644
--- a/src/app/services/FileSystem.ts
+++ b/src/app/services/FileSystem.ts
@@ -46,19 +46,22 @@ export class MixedFileSystem implements core.ExternalFileSystem {
 
 	constructor(
 		public readonly base: core.ExternalFileSystem,
-		public readonly overlays: Map<string, core.ExternalFileSystem> = new Map(),
-	) {}
+		public readonly overlays: { prefix: string, fs: core.ExternalFileSystem }[] = [],
+	) {
+		this.overlays.sort((a, b) => b.prefix.length - a.prefix.length)
+	}
 
-	async setOverlay(prefix: string, fileSystem: core.ExternalFileSystem) {
-		this.overlays.set(prefix, fileSystem)
+	async setOverlay(prefix: string, fs: core.ExternalFileSystem) {
+		this.overlays.push({ prefix, fs })
+		this.overlays.sort((a, b) => b.prefix.length - a.prefix.length)
 		if (this.watcher) {
-			await this.watcher.withOverlay(prefix, fileSystem)
+			await this.watcher.withOverlay(prefix, fs)
 		}
 		return this
 	}
 
 	getFileSystem(location: core.FsLocation) {
-		for (const [prefix, fs] of this.overlays.entries()) {
+		for (const { prefix, fs } of this.overlays) {
 			if (location.toString().startsWith(prefix)) {
 				return fs
 			}
@@ -105,7 +108,7 @@ class MixedWatcher extends BrowserEventEmitter implements core.FsWatcher {
 		super()
 		Promise.all([
 			this.initWatcher(fs.base, locations, options),
-			...[...fs.overlays.values()].map(overlay => this.initWatcher(overlay, locations, options)),
+			...fs.overlays.map(overlay => this.initWatcher(overlay.fs, locations, options)),
 		]).then(() => {
 			this.emit('ready')
 		})
diff --git a/src/app/services/Spyglass.ts b/src/app/services/Spyglass.ts
index 7919b7d9..9424926e 100644
--- a/src/app/services/Spyglass.ts
+++ b/src/app/services/Spyglass.ts
@@ -17,7 +17,7 @@ import siteConfig from '../Config.js'
 import { computeIfAbsent, genPath, message } from '../Utils.js'
 import type { VersionMeta } from './DataFetcher.js'
 import { fetchBlockStates, fetchRegistries, fetchVanillaMcdoc, fetchVersions, getVersionChecksum } from './DataFetcher.js'
-import { IndexedDbFileSystem, MixedFileSystem } from './FileSystem.js'
+import { IndexedDbFileSystem, MemoryFileSystem, MixedFileSystem } from './FileSystem.js'
 import type { VersionId } from './Versions.js'
 
 const builtinMcdoc = `
@@ -46,7 +46,9 @@ interface ClientDocument {
 }
 
 export class SpyglassClient {
-	public readonly fs = new MixedFileSystem(new IndexedDbFileSystem())
+	public readonly fs = new MixedFileSystem(new IndexedDbFileSystem(), [
+		{ prefix: 'file:///project/mcdoc/', fs: new MemoryFileSystem() },
+	])
 	public readonly externals: core.Externals = {
 		...BrowserExternals,
 		archive: {