From 18fa61c025aa0c1a2ae189cbc25bea0264ef9929 Mon Sep 17 00:00:00 2001
From: Aaron Miller <apage43@ninjawhale.com>
Date: Wed, 26 Apr 2023 17:57:25 -0700
Subject: [PATCH] download: atomically move tempfile when possible

should save unnecessary time and I/O and eliminate the possibility
of the file being improperly truncated when the temp file is on
the same filesystem as the destination path
---
 download.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/download.cpp b/download.cpp
index 0fb1d2e3..80dab3e2 100644
--- a/download.cpp
+++ b/download.cpp
@@ -286,6 +286,14 @@ void HashAndSaveFile::hashAndSave(const QString &expectedHash, const QString &sa
     // The file save needs the tempFile closed
     tempFile->close();
 
+    // Attempt to *move* the verified tempfile into place - this should be atomic
+    // but will only work if the destination is on the same filesystem
+    if (tempFile->rename(saveFilePath)) {
+        tempFile->setAutoRemove(false);
+        emit hashAndSaveFinished(true, tempFile, modelReply);
+        return;
+    }
+
     // Reopen the tempFile for copying
     if (!tempFile->open()) {
         qWarning() << "ERROR: Could not open temp file at finish:"