57ddc6f · reflex · git.iko.soy

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Add NOINLINE pragma to mkFastWeakTicket

57ddc6fTom Smalley7 years ago

src/Reflex/FastWeak.hs+10

compare with develop

unifiedsplit

@@ -151,6 +151,16 @@ getFastWeakTicket w = do

151

152-- | Create a 'FastWeakTicket' directly from a value, creating a 'FastWeak' in the process

153-- which can be obtained with 'getFastWeakTicketValue'.

154+--

155+-- This function is marked NOINLINE so it is opaque to GHC.

156+-- If we do not do this, then GHC will sometimes fuse the constructor away

157+-- so any weak references that are attached to the ticket will have their

158+-- finalizer run. Using the opaque constructor, GHC does not see the

159+-- constructor application, so it behaves like an IORef and cannot be fused away.

160+--

161+-- The result is also evaluated to WHNF, since forcing a thunk invalidates

162+-- the weak pointer to it in some cases.

163+{-# NOINLINE mkFastWeakTicket #-}

154mkFastWeakTicket :: a -> IO (FastWeakTicket a)

164mkFastWeakTicket :: a -> IO (FastWeakTicket a)

155-- I think it's fine if this is lazy - it'll retain the 'a', but so would the output; we just need to make sure it's forced before we start relying on the

165-- I think it's fine if this is lazy - it'll retain the 'a', but so would the output; we just need to make sure it's forced before we start relying on the

156-- associated FastWeak to actually be weak

166-- associated FastWeak to actually be weak

src/Reflex/Spider/Internal.hs−10

@@ -450,16 +450,6 @@ data Subscriber x a = Subscriber

450 , subscriberRecalculateHeight :: !(Height -> IO ())

451 }

452

453−--TODO: Move this comment to WeakBag

454−-- These function are constructor functions that are marked NOINLINE so they are

455−-- opaque to GHC. If we do not do this, then GHC will sometimes fuse the constructor away

456−-- so any weak references that are attached to the constructors will have their

457−-- finalizer run. Using the opaque constructor, does not see the

458−-- constructor application, so it behaves like an IORef and cannot be fused away.

459−--

460−-- The result is also evaluated to WHNF, since forcing a thunk invalidates

461−-- the weak pointer to it in some cases.

462−

463newSubscriberHold :: (HasSpiderTimeline x, Patch p) => Hold x p -> IO (Subscriber x p)

453newSubscriberHold :: (HasSpiderTimeline x, Patch p) => Hold x p -> IO (Subscriber x p)

464newSubscriberHold h = return $ Subscriber

454newSubscriberHold h = return $ Subscriber

465 { subscriberPropagate = {-# SCC "traverseHold" #-} propagateSubscriberHold h

455 { subscriberPropagate = {-# SCC "traverseHold" #-} propagateSubscriberHold h