From 0d0fc21e923c1645e860135d4c08490344ba1533 Mon Sep 17 00:00:00 2001
From: Jens Nolte <git@queezle.net>
Date: Wed, 25 Aug 2021 18:37:33 +0200
Subject: [PATCH] Fix (+rewrite) FnDisposable.dispose
---
src/Quasar/Disposable.hs | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/src/Quasar/Disposable.hs b/src/Quasar/Disposable.hs
index f33a1d4..d35f01f 100644
--- a/src/Quasar/Disposable.hs
+++ b/src/Quasar/Disposable.hs
@@ -80,13 +80,16 @@ instance IsAwaitable () Disposable where
newtype FnDisposable = FnDisposable (TMVar (Either (IO (Awaitable ())) (Awaitable ())))
instance IsDisposable FnDisposable where
- dispose (FnDisposable var) =
- bracketOnError
- do atomically $ takeTMVar var
- do atomically . putTMVar var
- \case
- Left action -> do
- awaitable <- action
+ dispose (FnDisposable var) = do
+ mask \restore -> do
+ eitherVal <- atomically do
+ takeTMVar var >>= \case
+ l@(Left _action) -> pure l
+ -- If the var contains an awaitable its put back immediately to save a second transaction
+ r@(Right _awaitable) -> r <$ putTMVar var r
+ case eitherVal of
+ l@(Left action) -> do
+ awaitable <- restore action `onException` atomically (putTMVar var l)
atomically $ putTMVar var $ Right awaitable
pure awaitable
Right awaitable -> pure awaitable
--
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