diff --git a/CHANGELOG.md b/CHANGELOG.md new file mode 100644 --- /dev/null +++ b/CHANGELOG.md @@ -0,0 +1,6 @@ +# Changelog + +## 1.0.0.0 + +* initial version + diff --git a/LICENSE b/LICENSE new file mode 100644 --- /dev/null +++ b/LICENSE @@ -0,0 +1,177 @@ + + Apache License + Version 2.0, January 2004 + http://www.apache.org/licenses/ + + TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION + + 1. Definitions. + + "License" shall mean the terms and conditions for use, reproduction, + and distribution as defined by Sections 1 through 9 of this document. + + "Licensor" shall mean the copyright owner or entity authorized by + the copyright owner that is granting the License. + + "Legal Entity" shall mean the union of the acting entity and all + other entities that control, are controlled by, or are under common + control with that entity. For the purposes of this definition, + "control" means (i) the power, direct or indirect, to cause the + direction or management of such entity, whether by contract or + otherwise, or (ii) ownership of fifty percent (50%) or more of the + outstanding shares, or (iii) beneficial ownership of such entity. + + "You" (or "Your") shall mean an individual or Legal Entity + exercising permissions granted by this License. + + "Source" form shall mean the preferred form for making modifications, + including but not limited to software source code, documentation + source, and configuration files. + + "Object" form shall mean any form resulting from mechanical + transformation or translation of a Source form, including but + not limited to compiled object code, generated documentation, + and conversions to other media types. + + "Work" shall mean the work of authorship, whether in Source or + Object form, made available under the License, as indicated by a + copyright notice that is included in or attached to the work + (an example is provided in the Appendix below). + + "Derivative Works" shall mean any work, whether in Source or Object + form, that is based on (or derived from) the Work and for which the + editorial revisions, annotations, elaborations, or other modifications + represent, as a whole, an original work of authorship. For the purposes + of this License, Derivative Works shall not include works that remain + separable from, or merely link (or bind by name) to the interfaces of, + the Work and Derivative Works thereof. + + "Contribution" shall mean any work of authorship, including + the original version of the Work and any modifications or additions + to that Work or Derivative Works thereof, that is intentionally + submitted to Licensor for inclusion in the Work by the copyright owner + or by an individual or Legal Entity authorized to submit on behalf of + the copyright owner. For the purposes of this definition, "submitted" + means any form of electronic, verbal, or written communication sent + to the Licensor or its representatives, including but not limited to + communication on electronic mailing lists, source code control systems, + and issue tracking systems that are managed by, or on behalf of, the + Licensor for the purpose of discussing and improving the Work, but + excluding communication that is conspicuously marked or otherwise + designated in writing by the copyright owner as "Not a Contribution." + + "Contributor" shall mean Licensor and any individual or Legal Entity + on behalf of whom a Contribution has been received by Licensor and + subsequently incorporated within the Work. + + 2. Grant of Copyright License. Subject to the terms and conditions of + this License, each Contributor hereby grants to You a perpetual, + worldwide, non-exclusive, no-charge, royalty-free, irrevocable + copyright license to reproduce, prepare Derivative Works of, + publicly display, publicly perform, sublicense, and distribute the + Work and such Derivative Works in Source or Object form. + + 3. Grant of Patent License. Subject to the terms and conditions of + this License, each Contributor hereby grants to You a perpetual, + worldwide, non-exclusive, no-charge, royalty-free, irrevocable + (except as stated in this section) patent license to make, have made, + use, offer to sell, sell, import, and otherwise transfer the Work, + where such license applies only to those patent claims licensable + by such Contributor that are necessarily infringed by their + Contribution(s) alone or by combination of their Contribution(s) + with the Work to which such Contribution(s) was submitted. If You + institute patent litigation against any entity (including a + cross-claim or counterclaim in a lawsuit) alleging that the Work + or a Contribution incorporated within the Work constitutes direct + or contributory patent infringement, then any patent licenses + granted to You under this License for that Work shall terminate + as of the date such litigation is filed. + + 4. Redistribution. You may reproduce and distribute copies of the + Work or Derivative Works thereof in any medium, with or without + modifications, and in Source or Object form, provided that You + meet the following conditions: + + (a) You must give any other recipients of the Work or + Derivative Works a copy of this License; and + + (b) You must cause any modified files to carry prominent notices + stating that You changed the files; and + + (c) You must retain, in the Source form of any Derivative Works + that You distribute, all copyright, patent, trademark, and + attribution notices from the Source form of the Work, + excluding those notices that do not pertain to any part of + the Derivative Works; and + + (d) If the Work includes a "NOTICE" text file as part of its + distribution, then any Derivative Works that You distribute must + include a readable copy of the attribution notices contained + within such NOTICE file, excluding those notices that do not + pertain to any part of the Derivative Works, in at least one + of the following places: within a NOTICE text file distributed + as part of the Derivative Works; within the Source form or + documentation, if provided along with the Derivative Works; or, + within a display generated by the Derivative Works, if and + wherever such third-party notices normally appear. The contents + of the NOTICE file are for informational purposes only and + do not modify the License. You may add Your own attribution + notices within Derivative Works that You distribute, alongside + or as an addendum to the NOTICE text from the Work, provided + that such additional attribution notices cannot be construed + as modifying the License. + + You may add Your own copyright statement to Your modifications and + may provide additional or different license terms and conditions + for use, reproduction, or distribution of Your modifications, or + for any such Derivative Works as a whole, provided Your use, + reproduction, and distribution of the Work otherwise complies with + the conditions stated in this License. + + 5. Submission of Contributions. Unless You explicitly state otherwise, + any Contribution intentionally submitted for inclusion in the Work + by You to the Licensor shall be under the terms and conditions of + this License, without any additional terms or conditions. + Notwithstanding the above, nothing herein shall supersede or modify + the terms of any separate license agreement you may have executed + with Licensor regarding such Contributions. + + 6. Trademarks. This License does not grant permission to use the trade + names, trademarks, service marks, or product names of the Licensor, + except as required for reasonable and customary use in describing the + origin of the Work and reproducing the content of the NOTICE file. + + 7. Disclaimer of Warranty. Unless required by applicable law or + agreed to in writing, Licensor provides the Work (and each + Contributor provides its Contributions) on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or + implied, including, without limitation, any warranties or conditions + of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A + PARTICULAR PURPOSE. You are solely responsible for determining the + appropriateness of using or redistributing the Work and assume any + risks associated with Your exercise of permissions under this License. + + 8. Limitation of Liability. In no event and under no legal theory, + whether in tort (including negligence), contract, or otherwise, + unless required by applicable law (such as deliberate and grossly + negligent acts) or agreed to in writing, shall any Contributor be + liable to You for damages, including any direct, indirect, special, + incidental, or consequential damages of any character arising as a + result of this License or out of the use or inability to use the + Work (including but not limited to damages for loss of goodwill, + work stoppage, computer failure or malfunction, or any and all + other commercial damages or losses), even if such Contributor + has been advised of the possibility of such damages. + + 9. Accepting Warranty or Additional Liability. While redistributing + the Work or Derivative Works thereof, You may choose to offer, + and charge a fee for, acceptance of support, warranty, indemnity, + or other liability obligations and/or rights consistent with this + License. However, in accepting such obligations, You may act only + on Your own behalf and on Your sole responsibility, not on behalf + of any other Contributor, and only if You agree to indemnify, + defend, and hold each Contributor harmless for any liability + incurred by, or claims asserted against, such Contributor by reason + of your accepting any such warranty or additional liability. + + END OF TERMS AND CONDITIONS diff --git a/NOTICE b/NOTICE new file mode 100644 --- /dev/null +++ b/NOTICE @@ -0,0 +1,14 @@ +Copyright 2019-2023 Input Output Global Inc (IOG) + + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. + diff --git a/README.md b/README.md new file mode 100644 --- /dev/null +++ b/README.md @@ -0,0 +1,21 @@ +# [SI] Timers + +The `si-timers` package provides delays & timeouts which are safe on 32-bit +systems; cancellable timeouts (see `registerDelayCancellable`); a refined +interface for monotonic `Time`. `Time` is given with left monoid action of +`DiffTime` (which encodes the notion of time differences). The +`MonadMonotonicTime`, `MonadDelay` type classes & `MonadTimers` (type synonym) +API provide a consistent interface for working with delays and timeouts. + +`si-timers` package also defined a low level `MonadTimout` type class. On +system with a native timer manager (e.g. `Linux`, `MacOS`, `FreeBSD`), it's +very efficient but for other platforms (e.g. `Windows`), it might not be the +right API for low latency timeouts needed for example for low level networking +code, because it relies on `GHC`'s `RTS` thread scheduling. + +`si-timers` are compatible with `io-sim`. + +The `SI` comes from the [International System of Units][SI]. + +[SI]: https://www.wikiwand.com/en/International_System_of_Units +[`io-sim`]: https://hackage.haskell.org/package/io-sim diff --git a/si-timers.cabal b/si-timers.cabal new file mode 100644 --- /dev/null +++ b/si-timers.cabal @@ -0,0 +1,82 @@ +cabal-version: 3.0 +name: si-timers +version: 1.0.0.0 +synopsis: timers using SI units (seconds) +description: + Timers using SI units (seconds) which are safe on 32-bit platforms and + compatible with [io-sim](https://hackage.haskell.org/package/io-sim). +license: Apache-2.0 +license-files: + LICENSE + NOTICE +copyright: 2022-2023 Input Output Global Inc (IOG) +author: Duncan Coutts, Neil Davis, Marcin Szamotulski +maintainer: Duncan Coutts duncan@well-typed.com, Marcin Szamotulski coot@coot.me +category: Control +build-type: Simple +extra-source-files: CHANGELOG.md + README.md +tested-with: GHC == { 8.10, 9.2, 9.4 } + +flag asserts + description: Enable assertions + manual: False + default: False + +source-repository head + type: git + location: https://github.com/input-output-hk/io-sim + subdir: io-sim + +common warnings + ghc-options: -Wall + -Wcompat + -Widentities + -Wincomplete-record-updates + -Wincomplete-uni-patterns + -Wno-unticked-promoted-constructors + -Wpartial-fields + -Wredundant-constraints + -Wunused-packages + +library + import: warnings + hs-source-dirs: src + exposed-modules: Control.Monad.Class.MonadTime.SI + Control.Monad.Class.MonadTimer.SI + other-modules: Control.Monad.Class.MonadTimer.NonStandard + default-language: Haskell2010 + other-extensions: BangPatterns, + CPP, + ConstraintKinds, + DefaultSignatures, + DeriveGeneric, + NumericUnderscores, + ScopedTypeVariables, + TypeFamilies + build-depends: base >=4.9 && <4.18, + mtl, + stm, + time >=1.9.1 && <1.13, + + io-classes ^>=1.0 + if flag(asserts) + ghc-options: -fno-ignore-asserts + +-- Since `io-sim` depends on `si-times` (`io-sim` depends on `Time`) some tests of +-- are in `io-sim:test`: this is a good enough reason to pull `io-sim:test` +-- into a seprate package. +test-suite test + import: warnings + type: exitcode-stdio-1.0 + hs-source-dirs: test + main-is: Main.hs + other-modules: Test.MonadTimer + default-language: Haskell2010 + build-depends: base, + + QuickCheck, + tasty, + tasty-quickcheck, + + si-timers diff --git a/src/Control/Monad/Class/MonadTime/SI.hs b/src/Control/Monad/Class/MonadTime/SI.hs new file mode 100644 --- /dev/null +++ b/src/Control/Monad/Class/MonadTime/SI.hs @@ -0,0 +1,69 @@ +{-# LANGUAGE DefaultSignatures #-} +{-# LANGUAGE DeriveGeneric #-} +{-# LANGUAGE NumericUnderscores #-} + +module Control.Monad.Class.MonadTime.SI + ( MonadTime (..) + , MonadMonotonicTime (..) + -- * 'DiffTime' and its action on 'Time' + , Time (..) + , diffTime + , addTime + , DiffTime + -- * 'NominalTime' and its action on 'UTCTime' + , UTCTime + , diffUTCTime + , addUTCTime + , NominalDiffTime + ) where + +import Control.Monad.Reader + +import Control.Monad.Class.MonadTime ( MonadMonotonicTimeNSec, + MonadTime (..), NominalDiffTime, UTCTime, diffUTCTime, + addUTCTime) +import qualified Control.Monad.Class.MonadTime as MonadTime + +import Data.Word (Word64) +import Data.Time.Clock (DiffTime) +import qualified Data.Time.Clock as Time +import GHC.Generics (Generic (..)) + + +-- | A point in time in a monotonic clock. +-- +-- The epoch for this clock is arbitrary and does not correspond to any wall +-- clock or calendar, and is /not guaranteed/ to be the same epoch across +-- program runs. It is represented as the 'DiffTime' from this arbitrary epoch. +-- +newtype Time = Time DiffTime + deriving (Eq, Ord, Show, Generic) + +-- | The time duration between two points in time (positive or negative). +diffTime :: Time -> Time -> DiffTime +diffTime (Time t) (Time t') = t - t' + +-- | Add a duration to a point in time, giving another time. +addTime :: DiffTime -> Time -> Time +addTime d (Time t) = Time (d + t) + +infixr 9 `addTime` + +class MonadMonotonicTimeNSec m => MonadMonotonicTime m where + getMonotonicTime :: m Time + + default getMonotonicTime :: m Time + getMonotonicTime = + conv <$> MonadTime.getMonotonicTimeNSec + where + conv :: Word64 -> Time + conv = Time . Time.picosecondsToDiffTime . (* 1_000) . toInteger + +instance MonadMonotonicTime IO where + +-- +-- MTL instances +-- + +instance MonadMonotonicTime m => MonadMonotonicTime (ReaderT r m) where + getMonotonicTime = lift getMonotonicTime diff --git a/src/Control/Monad/Class/MonadTimer/NonStandard.hs b/src/Control/Monad/Class/MonadTimer/NonStandard.hs new file mode 100644 --- /dev/null +++ b/src/Control/Monad/Class/MonadTimer/NonStandard.hs @@ -0,0 +1,168 @@ +{-# LANGUAGE CPP #-} +{-# LANGUAGE NumericUnderscores #-} +{-# LANGUAGE TypeFamilies #-} + +#if defined(__GLASGOW_HASKELL__) && \ + !defined(mingw32_HOST_OS) && \ + !defined(__GHCJS__) && \ + !defined(js_HOST_ARCH) && \ + !defined(wasm32_HOST_ARCH) +#define GHC_TIMERS_API +#endif + +-- | A non-standard interface for timer api. +-- +-- This module also provides a polyfill which allows to use timer api also on +-- non-threaded RTS regardless of the architecture \/ OS. Currently we support +-- `*nix`, `macOS`, `Windows` (and, unofficially `GHCJS`). +-- +-- We use it to provide @'Control.Monad.Class.MonadTimer.MonadTimer' 'IO'@ +-- instance and to implement a cancellable timers, see +-- 'Control.Monad.Class.MonadTimer.SI.registerDelayCancellable'. +-- +-- You can expect we will deprecate it at some point (e.g. once GHC gets +-- a better support for timers especially across different execution +-- environments). +-- +module Control.Monad.Class.MonadTimer.NonStandard + ( TimeoutState (..) + , newTimeout + , readTimeout + , cancelTimeout + , awaitTimeout + , NewTimeout + , ReadTimeout + , CancelTimeout + , AwaitTimeout + ) where + +import qualified Control.Concurrent.STM as STM +#ifndef GHC_TIMERS_API +import Control.Monad (when) +#endif +import Control.Monad.Class.MonadSTM + +#ifdef GHC_TIMERS_API +import qualified GHC.Event as GHC (TimeoutKey, getSystemTimerManager, + registerTimeout, unregisterTimeout) +#else +import qualified GHC.Conc.IO as GHC (registerDelay) +#endif + + +-- | State of a timeout: pending, fired or cancelled. +-- +data TimeoutState = TimeoutPending | TimeoutFired | TimeoutCancelled + deriving (Eq, Ord, Show) + + +-- | The type of the timeout handle, used with 'newTimeout', 'readTimeout', and +-- 'cancelTimeout'. +-- +#ifdef GHC_TIMERS_API +data Timeout = TimeoutIO !(STM.TVar TimeoutState) !GHC.TimeoutKey +#else +data Timeout = TimeoutIO !(STM.TVar (STM.TVar Bool)) !(STM.TVar Bool) +#endif + +-- | Create a new timeout which will fire at the given time duration in +-- the future. +-- +-- The timeout will start in the 'TimeoutPending' state and either +-- fire at or after the given time leaving it in the 'TimeoutFired' state, +-- or it may be cancelled with 'cancelTimeout', leaving it in the +-- 'TimeoutCancelled' state. +-- +-- Timeouts /cannot/ be reset to the pending state once fired or cancelled +-- (as this would be very racy). You should create a new timeout if you need +-- this functionality. +-- +-- When native timer manager is supported (on `*nix` systems), it only holds +-- a `TVar` with `TimeoutState` and `GHC.TimeoutKey`. +-- +newTimeout :: NewTimeout IO Timeout +type NewTimeout m timeout = Int -> m timeout + + +-- | Read the current state of a timeout. This does not block, but returns +-- the current state. It is your responsibility to use 'retry' to wait. +-- +-- Alternatively you may wish to use the convenience utility 'awaitTimeout' +-- to wait for just the fired or cancelled outcomes. +-- +-- You should consider the cancelled state if you plan to use 'cancelTimeout'. +-- +readTimeout :: ReadTimeout IO Timeout +type ReadTimeout m timeout = timeout -> STM m TimeoutState + + +-- | Cancel a timeout (unless it has already fired), putting it into the +-- 'TimeoutCancelled' state. Code reading and acting on the timeout state +-- need to handle such cancellation appropriately. +-- +-- It is safe to race this concurrently against the timer firing. It will +-- have no effect if the timer fires first. +-- +cancelTimeout :: CancelTimeout IO Timeout +type CancelTimeout m timeout = timeout -> m () + +-- | Returns @True@ when the timeout is fired, or @False@ if it is cancelled. +awaitTimeout :: AwaitTimeout IO Timeout +type AwaitTimeout m timeout = timeout -> STM m Bool + + +#ifdef GHC_TIMERS_API + +readTimeout (TimeoutIO var _key) = STM.readTVar var + +newTimeout = \d -> do + var <- STM.newTVarIO TimeoutPending + mgr <- GHC.getSystemTimerManager + key <- GHC.registerTimeout mgr d (STM.atomically (timeoutAction var)) + return (TimeoutIO var key) + where + timeoutAction var = do + x <- STM.readTVar var + case x of + TimeoutPending -> STM.writeTVar var TimeoutFired + TimeoutFired -> error "MonadTimer(IO): invariant violation" + TimeoutCancelled -> return () + +cancelTimeout (TimeoutIO var key) = do + STM.atomically $ do + x <- STM.readTVar var + case x of + TimeoutPending -> STM.writeTVar var TimeoutCancelled + TimeoutFired -> return () + TimeoutCancelled -> return () + mgr <- GHC.getSystemTimerManager + GHC.unregisterTimeout mgr key + +#else + +readTimeout (TimeoutIO timeoutvarvar cancelvar) = do + canceled <- STM.readTVar cancelvar + fired <- STM.readTVar =<< STM.readTVar timeoutvarvar + case (canceled, fired) of + (True, _) -> return TimeoutCancelled + (_, False) -> return TimeoutPending + (_, True) -> return TimeoutFired + +newTimeout d = do + timeoutvar <- GHC.registerDelay d + timeoutvarvar <- STM.newTVarIO timeoutvar + cancelvar <- STM.newTVarIO False + return (TimeoutIO timeoutvarvar cancelvar) + +cancelTimeout (TimeoutIO timeoutvarvar cancelvar) = + STM.atomically $ do + fired <- STM.readTVar =<< STM.readTVar timeoutvarvar + when (not fired) $ STM.writeTVar cancelvar True + +#endif + +awaitTimeout t = do s <- readTimeout t + case s of + TimeoutPending -> retry + TimeoutFired -> return True + TimeoutCancelled -> return False diff --git a/src/Control/Monad/Class/MonadTimer/SI.hs b/src/Control/Monad/Class/MonadTimer/SI.hs new file mode 100644 --- /dev/null +++ b/src/Control/Monad/Class/MonadTimer/SI.hs @@ -0,0 +1,262 @@ +{-# LANGUAGE ConstraintKinds #-} +{-# LANGUAGE InstanceSigs #-} +{-# LANGUAGE LambdaCase #-} +{-# LANGUAGE NumericUnderscores #-} +{-# LANGUAGE ScopedTypeVariables #-} + +module Control.Monad.Class.MonadTimer.SI + ( -- * Type classes + MonadDelay (..) + , MonadTimer (..) + -- * Auxiliary functions + , diffTimeToMicrosecondsAsInt + , microsecondsAsIntToDiffTime + -- * Re-exports + , DiffTime + , MonadFork + , MonadMonotonicTime + , MonadTime + , TimeoutState (..) + -- * Default implementations + , defaultRegisterDelay + , defaultRegisterDelayCancellable + ) where + +import Control.Concurrent.Class.MonadSTM +import Control.Exception (assert) +import Control.Monad.Class.MonadFork +import Control.Monad.Class.MonadTime.SI +import qualified Control.Monad.Class.MonadTimer as MonadTimer +import Control.Monad.Class.MonadTimer.NonStandard (TimeoutState (..)) +import qualified Control.Monad.Class.MonadTimer.NonStandard as NonStandard + +import Control.Monad.Reader + +import Data.Bifunctor (bimap) +import Data.Functor (($>)) +import Data.Time.Clock (diffTimeToPicoseconds) + + + +-- | Convert 'DiffTime' in seconds to microseconds represented by an 'Int'. +-- +-- Note that on 32bit systems it can only represent `2^31-1` seconds, which is +-- only ~35 minutes. +diffTimeToMicrosecondsAsInt :: DiffTime -> Int +diffTimeToMicrosecondsAsInt d = + let usec :: Integer + usec = diffTimeToPicoseconds d `div` 1_000_000 in + assert (usec <= fromIntegral (maxBound :: Int)) $ + fromIntegral usec + + +-- | Convert time in microseconds in 'DiffTime' (measured in seconds). +-- +microsecondsAsIntToDiffTime :: Int -> DiffTime +microsecondsAsIntToDiffTime = (/ 1_000_000) . fromIntegral + +class ( MonadTimer.MonadDelay m + , MonadMonotonicTime m + ) => MonadDelay m where + threadDelay :: DiffTime -> m () + +-- | Thread delay. When the delay is smaller than what `Int` can represent it +-- will use the `Control.Monad.Class.MonadTimer.threadDelay` (e.g. for the `IO` +-- monad it will use `Control.Concurrent.threadDelay`); otherwise it will +-- recursively call `Control.Monad.Class.MonadTimer.threadDelay`. +-- +instance MonadDelay IO where + threadDelay :: forall m. + MonadDelay m + => DiffTime -> m () + threadDelay d | d <= maxDelay = + MonadTimer.threadDelay (diffTimeToMicrosecondsAsInt d) + where + maxDelay :: DiffTime + maxDelay = microsecondsAsIntToDiffTime maxBound + + threadDelay d = do + c <- getMonotonicTime + let u = d `addTime` c + go c u + where + maxDelay :: DiffTime + maxDelay = microsecondsAsIntToDiffTime maxBound + + go :: Time -> Time -> m () + go c u = do + if d' >= maxDelay + then do + MonadTimer.threadDelay maxBound + c' <- getMonotonicTime + go c' u + else + MonadTimer.threadDelay (diffTimeToMicrosecondsAsInt d') + where + d' = u `diffTime` c + +instance MonadDelay m => MonadDelay (ReaderT r m) where + threadDelay = lift . threadDelay + +class ( MonadTimer.MonadTimer m + , MonadMonotonicTime m + ) => MonadTimer m where + + -- | A register delay function which safe on 32-bit systems. + registerDelay :: DiffTime -> m (TVar m Bool) + + -- | A cancellable register delay which is safe on 32-bit systems and efficient + -- for delays smaller than what `Int` can represent (especially on systems which + -- support native timer manager). + -- + registerDelayCancellable :: DiffTime -> m (STM m TimeoutState, m ()) + + -- | A timeout function. + -- + -- TODO: 'IO' instance is not safe on 32-bit systems. + timeout :: DiffTime -> m a -> m (Maybe a) + + +-- | A default implementation of `registerDelay` which supports delays longer +-- then `Int`; this is especially important on 32-bit systems where maximum +-- delay expressed in microseconds is around 35 minutes. +-- +defaultRegisterDelay :: forall m timeout. + ( MonadFork m + , MonadMonotonicTime m + , MonadSTM m + ) + => NonStandard.NewTimeout m timeout + -> NonStandard.AwaitTimeout m timeout + -> DiffTime + -> m (TVar m Bool) +defaultRegisterDelay newTimeout awaitTimeout d = do + c <- getMonotonicTime + v <- atomically $ newTVar False + tid <- forkIO $ go v c (d `addTime` c) + labelThread tid "delay-thread" + return v + where + maxDelay :: DiffTime + maxDelay = microsecondsAsIntToDiffTime maxBound + + go :: TVar m Bool -> Time -> Time -> m () + go v c u | u `diffTime` c >= maxDelay = do + _ <- newTimeout maxBound >>= atomically . awaitTimeout + c' <- getMonotonicTime + go v c' u + + go v c u = do + t <- newTimeout (diffTimeToMicrosecondsAsInt $ u `diffTime` c) + atomically $ do + _ <- awaitTimeout t + writeTVar v True + + +-- | A cancellable register delay which is safe on 32-bit systems and efficient +-- for delays smaller than what `Int` can represent (especially on systems which +-- support native timer manager). +-- +defaultRegisterDelayCancellable :: forall m timeout. + ( MonadFork m + , MonadMonotonicTime m + , MonadSTM m + ) + => NonStandard.NewTimeout m timeout + -> NonStandard.ReadTimeout m timeout + -> NonStandard.CancelTimeout m timeout + -> NonStandard.AwaitTimeout m timeout + -> DiffTime + -> m (STM m TimeoutState, m ()) + +defaultRegisterDelayCancellable newTimeout readTimeout cancelTimeout _awaitTimeout d | d <= maxDelay = do + t <- newTimeout (diffTimeToMicrosecondsAsInt d) + return (readTimeout t, cancelTimeout t) + where + maxDelay :: DiffTime + maxDelay = microsecondsAsIntToDiffTime maxBound + +defaultRegisterDelayCancellable newTimeout _readTimeout _cancelTimeout awaitTimeout d = do + -- current time + c <- getMonotonicTime + -- timeout state + v <- newTVarIO TimeoutPending + tid <- forkIO $ go v c (d `addTime` c) + labelThread tid "delay-thread" + let cancel = atomically $ readTVar v >>= \case + TimeoutCancelled -> return () + TimeoutFired -> return () + TimeoutPending -> writeTVar v TimeoutCancelled + return (readTVar v, cancel) + where + maxDelay :: DiffTime + maxDelay = microsecondsAsIntToDiffTime maxBound + + go :: TVar m TimeoutState + -> Time + -> Time + -> m () + go v c u | u `diffTime` c >= maxDelay = do + t <- newTimeout maxBound + ts <- atomically $ do + (readTVar v >>= \case + a@TimeoutCancelled -> return a + TimeoutFired -> error "registerDelayCancellable: invariant violation!" + TimeoutPending -> retry) + `orElse` + -- the overall timeout is still pending when 't' fires + (awaitTimeout t $> TimeoutPending) + case ts of + TimeoutPending -> do + c' <- getMonotonicTime + go v c' u + _ -> return () + + go v c u = do + t <- newTimeout (diffTimeToMicrosecondsAsInt $ u `diffTime` c) + atomically $ do + ts <- (readTVar v >>= \case + a@TimeoutCancelled -> return a + TimeoutFired -> error "registerDelayCancellable: invariant violation!" + TimeoutPending -> retry) + `orElse` + -- the overall timeout fires when 't' fires + (awaitTimeout t $> TimeoutFired) + case ts of + TimeoutFired -> writeTVar v TimeoutFired + _ -> return () + + +-- | Like 'GHC.Conc.registerDelay' but safe on 32-bit systems. When the delay +-- is larger than what `Int` can represent it will fork a thread which will +-- write to the returned 'TVar' once the delay has passed. When the delay is +-- small enough it will use the `MonadTimer`'s `registerDelay` (e.g. for `IO` +-- monad it will use the `GHC`'s `GHC.Conc.registerDelay`). +-- +-- TODO: 'timeout' not safe on 32-bit systems. +instance MonadTimer IO where + registerDelay d + | d <= maxDelay = + MonadTimer.registerDelay (diffTimeToMicrosecondsAsInt d) + | otherwise = + defaultRegisterDelay + NonStandard.newTimeout + NonStandard.awaitTimeout + d + where + maxDelay :: DiffTime + maxDelay = microsecondsAsIntToDiffTime maxBound + + registerDelayCancellable = + defaultRegisterDelayCancellable + NonStandard.newTimeout + NonStandard.readTimeout + NonStandard.cancelTimeout + NonStandard.awaitTimeout + + timeout = MonadTimer.timeout . diffTimeToMicrosecondsAsInt + +instance MonadTimer m => MonadTimer (ReaderT r m) where + registerDelay = lift . registerDelay + registerDelayCancellable = fmap (bimap lift lift) . lift . registerDelayCancellable + timeout d f = ReaderT $ \r -> timeout d (runReaderT f r) diff --git a/test/Main.hs b/test/Main.hs new file mode 100644 --- /dev/null +++ b/test/Main.hs @@ -0,0 +1,15 @@ +module Main (main) where + +import Test.Tasty + +import qualified Test.MonadTimer + +main :: IO () +main = defaultMain tests + +tests :: TestTree +tests = + testGroup "io-classes" + [ Test.MonadTimer.tests + ] + diff --git a/test/Test/MonadTimer.hs b/test/Test/MonadTimer.hs new file mode 100644 --- /dev/null +++ b/test/Test/MonadTimer.hs @@ -0,0 +1,90 @@ +{-# LANGUAGE MultiWayIf #-} +{-# LANGUAGE NumericUnderscores #-} + +module Test.MonadTimer (tests) where + +import Control.Monad.Class.MonadTimer.SI +import GHC.Real + +import Test.QuickCheck +import Test.Tasty +import Test.Tasty.QuickCheck (testProperty) + +tests :: TestTree +tests = + testGroup "Control.Monad.Class.MonadTimer" + [ testProperty "diffTimeToMicroseconds left inverse" + prop_diffTimeToMicrosecondsAsIntLeftInverse + , testProperty "diffTimeToMicroseconds right inverse" + prop_diffTimeToMicrosecondsAsIntRightInverse + ] + +newtype IntDistr = IntDistr Int + deriving (Show, Eq) + +instance Arbitrary IntDistr where + arbitrary = oneof + [ IntDistr <$> arbitrary + , IntDistr . (maxBound - ) . getNonNegative <$> (arbitrary :: Gen (NonNegative Int)) + , IntDistr . (minBound + ) . getNonNegative <$> (arbitrary :: Gen (NonNegative Int)) + ] + + shrink (IntDistr a) = IntDistr `map` shrink a + +prop_diffTimeToMicrosecondsAsIntLeftInverse :: IntDistr -> Bool +prop_diffTimeToMicrosecondsAsIntLeftInverse (IntDistr usec) = + usec == diffTimeToMicrosecondsAsInt (microsecondsAsIntToDiffTime usec) + + +newtype DiffTimeDistr = DiffTimeDistr DiffTime + deriving (Show, Eq) + +instance Arbitrary DiffTimeDistr where + arbitrary = frequency + [ -- arbitrary DiffTime + (6, DiffTimeDistr . fromRational <$> arbitrary) + -- large positive DiffTimes, but smaller than `maxBound :: Int` microseconds + , (3, DiffTimeDistr + . (fromRational (toRational (maxBound :: Int) / 1_000_000) - ) + . fromRational + . getNonNegative + <$> resize 100 arbitrary + ) + -- large negative DiffTimes, but larger than `minBound :: Int` microseconds + , (3, DiffTimeDistr + . (fromRational (toRational (minBound :: Int) / 1_000_000) + ) + . fromRational + . getNonNegative + <$> arbitrary + ) + -- smaller than 1 :% 1_000_000 + , (1, DiffTimeDistr . fromRational . (/ 1_000_000) <$> resize 1 arbitrary) + ] + + shrink (DiffTimeDistr a) = (DiffTimeDistr . fromRational) `map` shrink (toRational a) + +prop_diffTimeToMicrosecondsAsIntRightInverse :: DiffTimeDistr -> Property +prop_diffTimeToMicrosecondsAsIntRightInverse (DiffTimeDistr a) = + label (labelRational (toRational a)) $ + abs (toRational a - a') < (1 :% 1_000_000) + .&&. + r === microsecondsAsIntToDiffTime (diffTimeToMicrosecondsAsInt r) + + + where + a' = toRational (microsecondsAsIntToDiffTime (diffTimeToMicrosecondsAsInt a)) + + -- 'a' rounded to microseconds + r :: DiffTime + r = fromRational (toRational x / 1_000_000) + where + x :: Integer + x = round $ (toRational a * 1_000_000) + + labelRational x = + if | abs x < 1 :% 1_000_000 + -> "small" + | abs x > toRational (maxBound :: Int) / 1_000_000 - 100 + -> "large" + | otherwise + -> "average"