From bb33cb9cd3fa7f93ce895cc25ed00f5c5e9373f7 Mon Sep 17 00:00:00 2001
From: Bodigrim <andrew.lelechenko@gmail.com>
Date: Sat, 13 Dec 2025 23:46:05 +0000
Subject: [PATCH] Write database to a temporary file, then rename

So that hitting Ctrl+C does not leave you with a corrupted database.

This is using `withTempFile` from `temporary` and not from `extra`,
because it comes with more handy bells and whistles.
---
 hoogle.cabal         | 1 +
 src/General/Store.hs | 9 +++++++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/hoogle.cabal b/hoogle.cabal
index cf70b6a7..1f97e25a 100644
--- a/hoogle.cabal
+++ b/hoogle.cabal
@@ -80,6 +80,7 @@ library
         storable-tuple,
         tar,
         template-haskell,
+        temporary,
         text >= 2,
         time >= 1.5,
         transformers,
diff --git a/src/General/Store.hs b/src/General/Store.hs
index d37082ed..e145340b 100644
--- a/src/General/Store.hs
+++ b/src/General/Store.hs
@@ -33,8 +33,11 @@ import General.Util
 import Numeric.Extra
 import Paths_hoogle
 import Prelude
-import System.IO.Extra
+import System.Directory (renameFile)
+import System.FilePath (takeDirectory, takeFileName)
+import System.IO.Extra (Handle, hTell, hClose, hPutBuf)
 import System.IO.MMap
+import System.IO.Temp (withTempFile)
 import System.IO.Unsafe
 
 -- Ensure the string is always 25 chars long, so version numbers don't change its size
@@ -108,7 +111,7 @@ storeWriteFile :: FilePath -> (StoreWrite -> IO a) -> IO ([String], a)
 storeWriteFile file act = do
     atoms <- newIORef Map.empty
     parts <- newIORef Nothing
-    withBinaryFile file WriteMode $ \h -> do
+    withTempFile (takeDirectory file) (takeFileName file) $ \tmpFile h -> do
         -- put the version string at the start and end, so we can tell truncation vs wrong version
         BS.hPut h verString
         ref <- newIORef $ SW h (BS.length verString) []
@@ -130,6 +133,8 @@ storeWriteFile file act = do
         let stats = prettyTable 0 "Bytes" $
                 ("Overheads", intToDouble $ fromIntegral final - sum (map atomSize $ Map.elems atoms)) :
                 [(name ++ " :: " ++ atomType, intToDouble atomSize) | (name, Atom{..}) <- Map.toList atoms]
+        hClose h
+        renameFile tmpFile file
         pure (stats, res)
 
 storeWrite :: (Typeable (t a), Typeable a, Stored a) => StoreWrite -> t a -> a -> IO ()