chore: import upstream snapshot with attribution

plugins/file-synchronizer/src/sync-queue/queue-batching.ts

@@ -0,0 +1,41 @@
+import { MAX_BATCH_SIZE_BYTES } from '../consts'
+import type * as types from '../types'
+
+type SimpleFile = Pick<types.SyncQueueItem, 'sizeInBytes'>
+
+export const findBatchEndCursor = ({
+  startCursor: unsafeStartCursor,
+  files,
+}: {
+  startCursor: number
+  files: SimpleFile[]
+}): { endCursor: number } => {
+  const startCursor = Math.min(Math.max(unsafeStartCursor, 0), files.length - 1)
+  let currentBatchSize = 0
+  let endCursor = files.length
+
+  for (let newCursor = startCursor; newCursor < files.length; newCursor++) {
+    const fileToSync = files[newCursor]
+    const fileSizeInBytes = _getFileSize(fileToSync!)
+    currentBatchSize += fileSizeInBytes
+
+    // First file is always included even if it exceeds the batch size:
+    if (newCursor > startCursor && currentBatchSize > MAX_BATCH_SIZE_BYTES) {
+      endCursor = newCursor
+      break
+    }
+  }
+
+  return { endCursor }
+}
+
+const _getFileSize = (file: SimpleFile) => {
+  if (file.sizeInBytes === undefined) {
+    // If a file has no size, we assume it takes up half the batch size limit.
+    // This should be relatively safe, since we'd process at most two files of
+    // unknown size in a batch, and we don't want to just skip them.
+    return MAX_BATCH_SIZE_BYTES / 2
+  }
+
+  return file.sizeInBytes
+}