xet chunker is created for each file instead of reused (#1738)

We need to create a fresh Chunker object for each file we process to
avoid the last bytes from the previous file to impact the hash used to
generate chunk boundaries.

This gets ride of the `try {} finally {chunker.free()}` at the end of
file processing so this causes a lot of code to be de-indented, changes
are pretty minimal.

Co-authored-by: coyotte508 <coyotte508@protonmail.com>

Author: assafvayner

packages/hub/src/utils/createXorbs.ts

@@ -112,7 +112,6 @@ export async function* createXorbs(
 	let xorbId = 0;
 
 	await chunkModule.init();
-	const chunker = new chunkModule.Chunker(TARGET_CHUNK_SIZE);
 	const chunkCache = new ChunkCache();
 	let xorb = new CurrentXorbInfo();
 
@@ -147,8 +146,9 @@ export async function* createXorbs(
 
 	const remoteXorbHashes: string[] = [""]; // starts at index 1 (to simplify implem a bit)
 
-	try {
-		for await (const fileSource of fileSources) {
+	for await (const fileSource of fileSources) {
+		const chunker = new chunkModule.Chunker(TARGET_CHUNK_SIZE);
+		try {
 			xorb.fileSize[fileSource.path] = fileSource.content.size;
 
 			// Load dedup info for the first chunk of the file, if it's potentially modified by the splice
@@ -342,22 +342,22 @@ export async function* createXorbs(
 				dedupRatio,
 				representation: fileRepresentation,
 			});
+		} finally {
+			chunker.free();
+			// ^ is this really needed ?
 		}
+	}
 
-		if (xorb.offset > 0) {
-			yield xorb.event(chunkModule.compute_xorb_hash.bind(chunkModule));
-		}
+	if (xorb.offset > 0) {
+		yield xorb.event(chunkModule.compute_xorb_hash.bind(chunkModule));
+	}
 
-		for (const event of pendingFileEvents) {
-			event.representation = event.representation.map((rep) => ({
-				...rep,
-				xorbId: (rep.xorbId as number) >= 0 ? rep.xorbId : remoteXorbHashes[-rep.xorbId],
-			}));
-			yield event;
-		}
-	} finally {
-		chunker.free();
-		// ^ is this really needed ?
+	for (const event of pendingFileEvents) {
+		event.representation = event.representation.map((rep) => ({
+			...rep,
+			xorbId: (rep.xorbId as number) >= 0 ? rep.xorbId : remoteXorbHashes[-rep.xorbId],
+		}));
+		yield event;
 	}
 }