From 3ddb523198def124bdd5f3170cf9f70ecd3f6d45 Mon Sep 17 00:00:00 2001
From: Nathan Rajlich <n@n8.io>
Date: Sun, 22 Dec 2024 15:43:55 -0800
Subject: [PATCH] Add `Switch.FileSystem.openWithId()`

---
 .changeset/grumpy-games-sleep.md           |  5 ++++
 packages/runtime/src/$.ts                  |  6 +++++
 packages/runtime/src/switch/file-system.ts | 28 ++++++++++++++++++++
 source/fsdev.c                             | 30 ++++++++++++++++++++++
 4 files changed, 69 insertions(+)
 create mode 100644 .changeset/grumpy-games-sleep.md

diff --git a/.changeset/grumpy-games-sleep.md b/.changeset/grumpy-games-sleep.md
new file mode 100644
index 00000000..3fbfdd03
--- /dev/null
+++ b/.changeset/grumpy-games-sleep.md
@@ -0,0 +1,5 @@
+---
+"@nx.js/runtime": patch
+---
+
+Add `Switch.FileSystem.openWithId()`
diff --git a/packages/runtime/src/$.ts b/packages/runtime/src/$.ts
index 71e2dfa2..c8333954 100644
--- a/packages/runtime/src/$.ts
+++ b/packages/runtime/src/$.ts
@@ -181,6 +181,12 @@ export interface Init {
 	fsMount(fs: FileSystem, name: string): void;
 	fsOpenBis(id: number): FileSystem;
 	fsOpenSdmc(): FileSystem;
+	fsOpenWithId(
+		titleId: bigint,
+		type: number,
+		path: string,
+		attributes: number,
+	): FileSystem;
 	saveDataInit(c: ClassOf<SaveData>): void;
 	saveDataCreateSync(info: SaveDataCreationInfo, nacp?: ArrayBuffer): void;
 	saveDataMount(saveData: SaveData, name: string): void;
diff --git a/packages/runtime/src/switch/file-system.ts b/packages/runtime/src/switch/file-system.ts
index 8dd64b91..d9598446 100644
--- a/packages/runtime/src/switch/file-system.ts
+++ b/packages/runtime/src/switch/file-system.ts
@@ -92,5 +92,33 @@ export class FileSystem {
 	static openSdmc(): FileSystem {
 		return proto($.fsOpenSdmc(), FileSystem);
 	}
+
+	/**
+	 * Opens a file system partition for the application with the specified title ID.
+	 * The file system type is specified by the `FsFileSystemType` parameter.
+	 *
+	 * @example
+	 *
+	 * ```typescript
+	 * import { FsFileSystemType } from '@nx.js/constants';
+	 *
+	 * // Open and mount the "User" partition
+	 * const fs = Switch.FileSystem.openWithId(
+	 *   0x0100000000001000n,
+	 *   FsFileSystemType.ContentMeta,
+	 * );
+	 * const url = fs.mount();
+	 *
+	 * // Read the file entries at the root of the file system
+	 * console.log(Switch.readDirSync(url));
+	 * ```
+	 *
+	 * @param titleId The title ID of the file system to open.
+	 * @param type The `FsFileSystemType` of the file system to open.
+	 * @param path The base path of the file system to open. Defaults to `/`.
+	 */
+	static openWithId(titleId: bigint, type: number, path?: string): FileSystem {
+		return proto($.fsOpenWithId(titleId, type, path ?? '/', 0), FileSystem);
+	}
 }
 $.fsInit(FileSystem);
diff --git a/source/fsdev.c b/source/fsdev.c
index 3583892d..6d559f47 100644
--- a/source/fsdev.c
+++ b/source/fsdev.c
@@ -116,6 +116,35 @@ static JSValue nx_fs_open_sdmc(JSContext *ctx, JSValueConst this_val, int argc,
 	return obj;
 }
 
+static JSValue nx_fs_open_with_id(JSContext *ctx, JSValueConst this_val,
+								  int argc, JSValueConst *argv) {
+	u64 title_id;
+	FsFileSystemType type;
+	FsContentAttributes attributes;
+	if (JS_ToBigUint64(ctx, &title_id, argv[0]) ||
+		JS_ToUint32(ctx, &type, argv[1]) ||
+		JS_ToUint32(ctx, &attributes, argv[3])) {
+		return JS_EXCEPTION;
+	}
+	const char *path = JS_ToCString(ctx, argv[2]);
+	if (!path) {
+		return JS_EXCEPTION;
+	}
+	nx_file_system_t *file_system = js_mallocz(ctx, sizeof(nx_file_system_t));
+	if (!file_system) {
+		JS_FreeCString(ctx, path);
+		return JS_EXCEPTION;
+	}
+	Result rc = fsOpenFileSystemWithId(&file_system->fs, title_id, type, path,
+									   attributes);
+	if (R_FAILED(rc)) {
+		return nx_throw_libnx_error(ctx, rc, "fsOpenFileSystemWithId()");
+	}
+	JSValue obj = JS_NewObjectClass(ctx, nx_file_system_class_id);
+	JS_SetOpaque(obj, file_system);
+	return obj;
+}
+
 static JSValue nx_fs_free_space(JSContext *ctx, JSValueConst this_val, int argc,
 								JSValueConst *argv) {
 	nx_file_system_t *file_system =
@@ -675,6 +704,7 @@ static const JSCFunctionListEntry function_list[] = {
 	JS_CFUNC_DEF("fsMount", 1, nx_fs_mount),
 	JS_CFUNC_DEF("fsOpenBis", 1, nx_fs_open_bis),
 	JS_CFUNC_DEF("fsOpenSdmc", 1, nx_fs_open_sdmc),
+	JS_CFUNC_DEF("fsOpenWithId", 1, nx_fs_open_with_id),
 
 	JS_CFUNC_DEF("saveDataInit", 1, nx_save_data_init),
 	JS_CFUNC_DEF("saveDataMount", 1, nx_save_data_mount),