From 6b9c8bced66853ed36379204a70b30ac5be223d2 Mon Sep 17 00:00:00 2001
From: Jakob Ackermann <jakob.ackermann@overleaf.com>
Date: Mon, 17 May 2021 14:18:07 +0100
Subject: [PATCH] [ContentCacheManager] write streams to disk atomically
Use an intermediate file for writing to disk, then rename to the target.
---
services/clsi/app/js/ContentCacheManager.js | 20 +++++++++++++++-----
1 file changed, 15 insertions(+), 5 deletions(-)
diff --git a/services/clsi/app/js/ContentCacheManager.js b/services/clsi/app/js/ContentCacheManager.js
index 94ed9ebc00..a32a952ca5 100644
--- a/services/clsi/app/js/ContentCacheManager.js
+++ b/services/clsi/app/js/ContentCacheManager.js
@@ -100,17 +100,27 @@ async function writePdfStream(dir, hash, buffers) {
// ETags used for client side caching via browser internals.
return false
} catch (e) {}
- const file = await fs.promises.open(filename, 'w')
+ const atomicWriteFilename = filename + '~'
+ const file = await fs.promises.open(atomicWriteFilename, 'w')
if (Settings.enablePdfCachingDark) {
// Write an empty file in dark mode.
buffers = []
}
try {
- for (const buffer of buffers) {
- await file.write(buffer)
+ try {
+ for (const buffer of buffers) {
+ await file.write(buffer)
+ }
+ } finally {
+ await file.close()
+ }
+ await fs.promises.rename(atomicWriteFilename, filename)
+ } catch (err) {
+ try {
+ await fs.promises.unlink(atomicWriteFilename)
+ } catch (_) {
+ throw err
}
- } finally {
- await file.close()
}
return true
}