From 13d465c1c45e649a702457d67476694aeb553704 Mon Sep 17 00:00:00 2001
From: Matt Strapp <matt@mattstrapp.net>
Date: Wed, 27 Sep 2023 16:16:10 -0500
Subject: Get rid of crc32, truncate instead

Signed-off-by: Matt Strapp <matt@mattstrapp.net>
---
 app/src/lib/ts/crc32.worker.ts    | 10 ----------
 app/src/lib/ts/download.ts        | 33 +++++++++++++++++++++++++++++++++
 app/src/lib/ts/truncate.worker.ts | 10 ++++++++++
 3 files changed, 43 insertions(+), 10 deletions(-)
 delete mode 100644 app/src/lib/ts/crc32.worker.ts
 create mode 100644 app/src/lib/ts/download.ts
 create mode 100644 app/src/lib/ts/truncate.worker.ts

(limited to 'app/src/lib/ts')

diff --git a/app/src/lib/ts/crc32.worker.ts b/app/src/lib/ts/crc32.worker.ts
deleted file mode 100644
index 57c1bc9..0000000
--- a/app/src/lib/ts/crc32.worker.ts
+++ /dev/null
@@ -1,10 +0,0 @@
-// TODO: Think about using a WebAssembly implementation of CRC32 instead of JavaScript.
-// WHY? The JavaScript implementation is not very extensible and is not very fast.
-import crc32 from 'crc/crc32';
-
-onmessage = async (message: MessageEvent<File>) => {
-  const file = message.data;
-  const buffer = await file.arrayBuffer();
-  const crc = crc32(buffer);
-  postMessage(crc);
-};
diff --git a/app/src/lib/ts/download.ts b/app/src/lib/ts/download.ts
new file mode 100644
index 0000000..a6167d7
--- /dev/null
+++ b/app/src/lib/ts/download.ts
@@ -0,0 +1,33 @@
+// Yoinked from https://web.dev/patterns/files/save-a-file/ for the polyfill
+
+export default async function saveFile(blob: ArrayBuffer, suggestedName: string | undefined) {
+	const supportsFSAccess = 'showSaveFilePicker' in window &&
+		(() => {
+			try {
+				return window.self === window.top;
+			} catch {
+				return false;
+			}
+		})();
+
+	if (supportsFSAccess) {
+		try {
+			const handle = await window.showSaveFilePicker({
+				suggestedName: suggestedName,
+			})
+			const writable = await handle.createWritable();
+			await writable.write(blob);
+			await writable.close();
+		} catch (err: unknown) {
+			// TypeScript
+			if ((err as Error)?.name !== 'AbortError') {
+				console.error(err);
+			}
+		}
+	} else {
+		const anchor = document.createElement('a');
+		anchor.download = suggestedName ?? 'truncated';
+		anchor.href = URL.createObjectURL(new Blob([blob]));
+		anchor.click();
+	}
+}
\ No newline at end of file
diff --git a/app/src/lib/ts/truncate.worker.ts b/app/src/lib/ts/truncate.worker.ts
new file mode 100644
index 0000000..52eebb7
--- /dev/null
+++ b/app/src/lib/ts/truncate.worker.ts
@@ -0,0 +1,10 @@
+import type { TruncateRequest, TruncateResponse } from '../types/truncate-worker';
+
+
+onmessage = async (message: MessageEvent<TruncateRequest>) => {
+	const file = message.data.file;
+	const buffer = await file.arrayBuffer();
+	const truncated = buffer.slice(0, message.data.size);
+
+	postMessage({ file: truncated } as TruncateResponse);
+}
\ No newline at end of file
-- 
cgit v1.2.3