make build work across server restart

tmp files disappear on server restart

src/file-utils.js

@@ -0,0 +1,23 @@
+import assert from 'node:assert';
+import { promises as fsPromises } from 'node:fs';
+import BoxError from './boxerror.js';
+import safe from 'safetydance';
+
+// cross device file rename
+async function renameFile(sourcePath, destPath) {
+    assert.strictEqual(typeof sourcePath, 'string');
+    assert.strictEqual(typeof destPath, 'string');
+    const [renameError] = await safe(fsPromises.rename(sourcePath, destPath));
+    if (renameError) {
+        if (renameError.code === 'EXDEV') {
+            const [copyError] = await safe(fsPromises.copyFile(sourcePath, destPath));
+            if (copyError) throw new BoxError(BoxError.FS_ERROR, copyError);
+            const [unlinkError] = await safe(fsPromises.unlink(sourcePath));
+            if (unlinkError) throw new BoxError(BoxError.FS_ERROR, unlinkError);
+        } else {
+            throw new BoxError(BoxError.FS_ERROR, renameError);
+        }
+    }
+}
+
+export default { renameFile };