Support string / URL initialization parameter to new Switch.Application()

Author: TooTallNate

.changeset/slimy-goats-confess.md

@@ -0,0 +1,5 @@
+---
+"@nx.js/runtime": patch
+---
+
+Support string / URL initialization parameter to `new Switch.Application()`

packages/runtime/src/$.ts

@@ -220,7 +220,7 @@ export interface Init {
 	// ns.c
 	nsInitialize(): () => void;
 	nsAppInit(c: ClassOf<Application>): void;
-	nsAppNew(id: BigInt | ArrayBuffer | null): Application;
+	nsAppNew(id: string | bigint | ArrayBuffer | null): Application;
 	nsAppNext(index: number): bigint | null;
 
 	// software-keyboard.c

packages/runtime/src/switch/ns.ts

@@ -1,8 +1,13 @@
 import { $ } from '../$';
+import { URL } from '../polyfills/url';
 import { SaveData, SaveDataCreationInfoWithNacp } from './savedata';
 import { inspect } from './inspect';
-import { readFileSync } from '../fs';
-import { FunctionPrototypeWithIteratorHelpers, proto, stub } from '../utils';
+import {
+	FunctionPrototypeWithIteratorHelpers,
+	pathToString,
+	proto,
+	stub,
+} from '../utils';
 import type { Profile } from './profile';
 
 let init = false;
@@ -75,6 +80,20 @@ export class Application {
 	 * @param id The ID of the installed application.
 	 */
 	constructor(id: bigint);
+	/**
+	 * Creates an `Application` instance from the string path
+	 * containing the contents of a `.nro` homebrew application.
+	 *
+	 * @example
+	 *
+	 * ```typescript
+	 * const app = new Switch.Application('sdmc:/hbmenu.nro');
+	 * console.log(app.name);
+	 * ```
+	 *
+	 * @param path The path of the `.nro` file.
+	 */
+	constructor(path: string | URL);
 	/**
 	 * Creates an `Application` instance from an `ArrayBuffer`
 	 * containing the contents of a `.nro` homebrew application.
@@ -90,9 +109,12 @@ export class Application {
 	 * @param nro The contents of the `.nro` file.
 	 */
 	constructor(nro: ArrayBuffer);
-	constructor(v: bigint | ArrayBuffer) {
+	constructor(v: string | bigint | ArrayBuffer | URL) {
 		_init();
-		return proto($.nsAppNew(v), Application);
+		return proto(
+			$.nsAppNew(v instanceof URL ? pathToString(v) : v),
+			Application,
+		);
 	}
 
 	/**
@@ -167,11 +189,11 @@ export class Application {
 	static get self(): Application {
 		if (!self) {
 			_init();
-			let nro: ArrayBuffer | null = null;
+			let p: string | null = null;
 			if ($.argv.length) {
-				nro = readFileSync($.argv[0]);
+				p = $.argv[0];
 			}
-			self = proto($.nsAppNew(nro), Application);
+			self = proto($.nsAppNew(p), Application);
 		}
 		return self;
 	}

source/ns.c

@@ -1,6 +1,7 @@
 #include "ns.h"
 #include "applet.h"
 #include "error.h"
+#include <errno.h>
 
 static JSClassID nx_app_class_id;
 
@@ -51,6 +52,49 @@ static JSValue nx_ns_app_new(JSContext *ctx, JSValueConst this_val, int argc,
 		if (JS_ToBigUint64(ctx, &application_id, argv[0])) {
 			return JS_EXCEPTION;
 		}
+	} else if (JS_IsString(argv[0])) {
+		// Get app ID from opening the path specified at the string value, which
+		// contains an NRO file.
+		const char *path = JS_ToCString(ctx, argv[0]);
+		if (!path) {
+			return JS_EXCEPTION;
+		}
+		FILE *file = fopen(path, "rb");
+		JS_FreeCString(ctx, path);
+
+		if (file == NULL) {
+			return nx_throw_errno_error(ctx, errno, "fopen()");
+		}
+
+		// Seek to offset 0x18 and read a u32 from the NRO file, which
+		// contains the offset of the asset header.
+		u32 asset_header_offset;
+		fseek(file, 0x18, SEEK_SET);
+		fread(&asset_header_offset, sizeof(u32), 1, file);
+
+		// Seek the file to the asset header offset and allocate buffer
+		uint8_t *asset_header = malloc(0x28); // Size needed for header info
+		fseek(file, asset_header_offset, SEEK_SET);
+		fread(asset_header, 0x28, 1, file);
+
+		u32 icon_section_offset = *(u32 *)(asset_header + 0x8);
+		u32 icon_section_size = *(u32 *)(asset_header + 0x10);
+		u32 nacp_section_offset = *(u32 *)(asset_header + 0x18);
+		u32 nacp_section_size = *(u32 *)(asset_header + 0x20);
+
+		// Seek to the icon section offset and read the icon data
+		fseek(file, asset_header_offset + icon_section_offset, SEEK_SET);
+		fread(&data->data.icon, icon_section_size, 1, file);
+
+		// Seek to the nacp section offset and read the nacp data
+		fseek(file, asset_header_offset + nacp_section_offset, SEEK_SET);
+		fread(&data->data.nacp, nacp_section_size, 1, file);
+
+		free(asset_header);
+		fclose(file);
+
+		data->icon_size = icon_section_size;
+		loaded = true;
 	} else {
 		// Get app ID from parsing the array buffer which contains an NRO file.
 		// This is the case when running the NRO through hbmenu or a forwarder.