msagent.js: misc cleanup

make wasm module stuff a bit less horrid and untyped so that it can maybe be reused for other things

msagent.js/core/package.json

@@ -1,5 +1,6 @@
 {
   "name": "@msagent.js/core",
+  "description": "msagent.js core. Provides structures, parsing, and bitmap utilties for higher level usage",
   "version": "0.1.0",
   "packageManager": "yarn@4.2.2",
   "devDependencies": {

msagent.js/core/src/decompress.ts

@@ -1,21 +1,19 @@
-// Please note that the "meaningless" shifts of 0 are to force
+import { WasmModule, WebassemblyOwnMemoryExports } from './wasm_module';
-// the value to be a 32-bit integer. Do not remove them.
 
-let compressWasm: WebAssembly.WebAssemblyInstantiatedSource;
+// WASM exports for the decompression module.
-
+interface CompressWasmExports extends WebassemblyOwnMemoryExports {
-interface CompressWasmExports {
+	agentDecompressWASM: (pSource: number, sourceLen: number, pDest: number, destLen: number) => number;
-	memory: WebAssembly.Memory;
-	agentDecompressWASM: any;
 }
 
+let compressWasm = new WasmModule<CompressWasmExports>(new URL('decompress.wasm', import.meta.url));
+
 // Initalize the decompression module
 export async function compressInit() {
-	let url = new URL('decompress.wasm', import.meta.url);
+	await compressWasm.Initalize();
-	compressWasm = await WebAssembly.instantiateStreaming(fetch(url));
 }
 
 function compressWasmGetExports() {
-	return compressWasm.instance.exports as any as CompressWasmExports;
+	return compressWasm.Exports;
 }
 
 function compressWASMGetMemory(): WebAssembly.Memory {
@@ -32,14 +30,9 @@ function compressWASMGetMemory(): WebAssembly.Memory {
 export function compressDecompress(src: Uint8Array, dest: Uint8Array) {
 	// Grow the WASM heap if needed. Funnily enough, this code is never hit in most
 	// ACSes, so IDK if it's even needed
-	let memory = compressWASMGetMemory();
+	compressWasm.growHeapTo(src.length + dest.length);
-	if (memory.buffer.byteLength < src.length + dest.length) {
-		// A WebAssembly page is 64kb, so we need to grow at least that much
-		let npages = Math.floor((src.length + dest.length) / 65535) + 1;
-		console.log('Need to grow WASM heap', npages, 'pages', '(current byteLength is', memory.buffer.byteLength, ', we need', src.length + dest.length, ')');
-		memory.grow(npages);
-	}
 
+	let memory = compressWASMGetMemory();
 	let copyBuffer = new Uint8Array(memory.buffer);
 
 	// Copy source to memory[0]. This will make things a bit simpler
@@ -50,6 +43,7 @@ export function compressDecompress(src: Uint8Array, dest: Uint8Array) {
 
 	if (nrBytesDecompressed != dest.length) throw new Error(`decompression failed: ${nrBytesDecompressed} != ${dest.length}`);
 
-	// Dest will be memory[src.length..dest.length]
+	// The uncompressed data is located at memory[src.length..dest.length].
+	// Copy it into the destination buffer.
 	dest.set(copyBuffer.slice(src.length, src.length + dest.length), 0);
 }

msagent.js/core/src/image.ts

@@ -38,7 +38,8 @@ export function imageDrawToBuffer(imageEntry: AcsImageEntry, palette: RGBAColor[
 		bufStream.seek(dwAlign(bufStream.tell()), SeekDir.BEG);
 	}
 
-	// Next, draw the rows converted to RGBA, top down (so it's drawn as you'd expect)
+	// Next, draw the rows converted to RGBA, top down (so it's drawn correctly,
+	// and in the RGBA format we want to return)
 	for (let y = 0; y < imageEntry.image.height - 1; ++y) {
 		let row = rows[y];
 		for (let x = 0; x < imageEntry.image.width; ++x) {

msagent.js/core/src/wasm_module.ts

@@ -0,0 +1,44 @@
+export interface WebassemblyOwnMemoryExports extends WebAssembly.Exports {
+	memory: WebAssembly.Memory;
+}
+
+// A helper for WASM modules.
+// This currently only works for modules that export their own memory,
+// and do not import it.
+//
+// This covers all of the modules in the core so far, so
+// this is perfectly fine, but it's still worth noting.
+export class WasmModule<TExports extends WebassemblyOwnMemoryExports> {
+	private module: WebAssembly.WebAssemblyInstantiatedSource | null = null;
+	private url: URL;
+
+	constructor(url: URL) {
+		this.url = url;
+	}
+
+	async Initalize(): Promise<void> {
+		this.module = await WebAssembly.instantiateStreaming(fetch(this.url));
+	}
+
+	get Module() {
+		if (this.module == null) throw new Error('WasmModule<T> has not been initalized');
+		return this.module;
+	}
+
+	get Exports() {
+		let module = this.Module;
+		return module.instance.exports as TExports;
+	}
+
+    // Grows the WebAssembly heap if required.
+	growHeapTo(newSize: number) {
+		let exports = this.Exports;
+		let memory: WebAssembly.Memory = exports.memory;
+		if (memory.buffer.byteLength < newSize) {
+			// A WebAssembly page is 64kb, so we need to grow at least a single page,
+			// even if it would be relatively wasteful to do so.
+			let npages = Math.floor(newSize / 65535) + 1;
+			memory.grow(npages);
+		}
+	}
+}

msagent.js/web/src/character.ts

@@ -5,6 +5,11 @@ import { Agent } from './agent.js';
 let acsDataCache = new Map<string, AcsData>();
 
 // Purges the ACS cache.
+//
+// FIXME: A smarter way to do this would probably be instead reference count
+// AcsData instances, then when an agent is disposed decrement reference count
+// (or leave it at 0). Once it's 0 then a globally running interval can remove
+// all keys that have no refcount.
 export function agentPurgeACSCache() {
 	acsDataCache.clear();
 }

yarn.lock

@@ -3619,11 +3619,11 @@ __metadata:
   linkType: hard
 
 "node-abi@npm:^3.3.0":
-  version: 3.65.0
+  version: 3.67.0
-  resolution: "node-abi@npm:3.65.0"
+  resolution: "node-abi@npm:3.67.0"
   dependencies:
     semver: "npm:^7.3.5"
-  checksum: 10c0/112672015d8f27d6be2f18d64569f28f5d6a15a94cc510da513c69c3e3ab5df6dac196ef13ff115a8fadb69b554974c47ef89b4f6350a2b02de2bca5c23db1e5
+  checksum: 10c0/72ce2edbdfb84745bc201a4e48aa7146fd88a0d2c80046b6b17f28439c9a7683eab846f40f1e819349c31f7d9331ed5c50d1e741208d938dd5f38b29cab2275e
   languageName: node
   linkType: hard
 
@@ -4246,7 +4246,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"semver@npm:^7.3.5, semver@npm:^7.3.8, semver@npm:^7.5.2, semver@npm:^7.5.4, semver@npm:^7.6.0":
+"semver@npm:^7.3.5, semver@npm:^7.5.2, semver@npm:^7.5.4, semver@npm:^7.6.0":
   version: 7.6.2
   resolution: "semver@npm:7.6.2"
   bin:
@@ -4255,6 +4255,15 @@ __metadata:
   languageName: node
   linkType: hard
 
+"semver@npm:^7.3.8":
+  version: 7.6.3
+  resolution: "semver@npm:7.6.3"
+  bin:
+    semver: bin/semver.js
+  checksum: 10c0/88f33e148b210c153873cb08cfe1e281d518aaa9a666d4d148add6560db5cd3c582f3a08ccb91f38d5f379ead256da9931234ed122057f40bb5766e65e58adaf
+  languageName: node
+  linkType: hard
+
 "seq-queue@npm:^0.0.5":
   version: 0.0.5
   resolution: "seq-queue@npm:0.0.5"