{-# LANGUAGE TypeSynonymInstances, MultiParamTypeClasses, FunctionalDependencies, FlexibleInstances, UndecidableInstances #-} {- -------------------------------------------------------------------------------- -- -- Copyright (C) 2008 Martin Sulzmann, Edmund Lam. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of Isaac Jones nor the names of other contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -} module MultiSetRewrite.StoreRepresentation where -- An actual representation of the store import IO import Data.IORef import Control.Concurrent import Control.Concurrent.STM import GHC.Conc import System.IO.Unsafe import Data.List import qualified MultiSetRewrite.ConcurrentList as L import qualified MultiSetRewrite.ConcurrentBag as B import MultiSetRewrite.Base import MultiSetRewrite.RuleSyntax import MultiSetRewrite.RuleCompiler ---------------------------------------- -- primitives for hashing messages type HashIdx = Int data HashOp msg = HashOp { numberOfTables :: HashIdx , hashMsg :: msg -> HashIdx } -- store representation data Store msg = Store { msgTable :: [B.Bag (InternalMsg msg)], hashOp :: HashOp msg } type Location msg = IORef (L.List (InternalMsg msg)) -- we need the location (pointer ref) of the message in internal form -- for quick access (eg logical delete) -- internal details of the store distribution = 7 -- we assume that store is -- a bag of linked lists -- NOTE: we could assume a different distribution for -- the individual messages -- The run-time distribution is currently monolithic -- We simply take the threadId 'mod' distribution instance (EMatch msg, Eq msg, Show msg) => RuleCompiler (Store msg) msg (Location msg) HashIdx (B.Iterator (InternalMsg msg)) where --atomicVerifyAndDeleteCnt :: Store msg -> Code_RHS a -- -> [(Check (Location msg),IO (Maybe (Code_RHS a)))] -> IO (Maybe (Code_RHS a)) -- we don't need the store here, but otherwise the method's type is ambiguous atomicVerifyAndDeleteCnt _ body checks = let -- reverify that all verify fields are True -- starting with the first field, -- if unsuccessful, return the continuation of the first failed field reVerify [] = return Nothing reVerify ((n,cnt):rest) = do let n' = case n of Verify n -> n VerifyAndDelete n -> n b <- readTVar n' if b then reVerify rest else return (Just cnt) -- we check and set to False simplified heads -- we only check propagated heads reVerifyAndSetFalse [] = return Nothing reVerifyAndSetFalse ((n,cnt):rest) = do case n of Verify n -> do b <- readTVar n if b then reVerifyAndSetFalse rest else return (Just cnt) VerifyAndDelete n -> do b <- readTVar n if b then do writeTVar n False reVerifyAndSetFalse rest else return (Just cnt) -- set verify fields to False -- only those which actually need to be deleted (the simp heads) setFalse [] = return () setFalse ((Verify _,_):ns) = setFalse ns setFalse ((VerifyAndDelete n,_):ns) = do writeTVar n False setFalse ns -- accumulates all deletes (only simp heads) -- must be performed in IO accDeletes [] = return () accDeletes ((Verify _,_):ns) = accDeletes ns accDeletes ((VerifyAndDelete msg,_):ns) = do node <- readIORef msg writeIORef msg (L.DelNode {L.verify = L.verify node, L.next = L.next node}) accDeletes ns -- verify all atomic guards, return continuation if unsuccessful verifyAtomicGuard [] = return Nothing verifyAtomicGuard ((g,cnt):rest) = case g of AtomicGuardVerify g -> do b <- g if b then verifyAtomicGuard rest else return (Just cnt) selectNode = \n -> case n of (Verify _,_) -> True (VerifyAndDelete _,_) -> True _ -> False checkNodes = filter selectNode checks -- select the to be verified nodes checkAtomicGuards = filter (not.selectNode) checks -- select the atomic guards (those with side-effects) -- side-effect guards have already been check earlier in do ns <- -- extract the to be verified fields -- from the IORef nodes mapM (\ (m,cnt) -> case m of Verify msg -> do node <- readIORef msg return (Verify (L.verify node),cnt) VerifyAndDelete msg -> do node <- readIORef msg return (VerifyAndDelete (L.verify node),cnt)) checkNodes -- perform atomic re-verification -- check that nodes are still there and -- check that atomic guards are true, if successful -- set node flags to False -- we continue by actually deleting the nodes followed by -- executing the body -- otherwise, we abort and -- (1) either pick the continuation of the -- first node which couldn't be reverified (back-jumping!) -- (2) if all nodes could be verified but the atomic guard caused failure -- pick the continuation of the last node -- (NOTE: atomic guards must be the last match tasks, simply because -- they contain side-effects and therefore they must be atomically -- checked as part of the re-verification phase) -- Version1 (uses side-effect we communicate which retry failed): -- in the first transaction -- (1) we reverify and set to false the fields -- (a) in case of failure, we collect the continuation -- we retry (to cancel all the set to false effects) -- and pass the continuation (as a side-effect) to -- the 'else' transaction -- (b) if successful continue with (2) -- (2) verify the atomic guards (with side-effects) -- (a) in case of failure, we collect the continuation -- we retry (to cancel all the set to false effects) -- and pass the continuation (as a side-effect) to -- the 'else' transaction (see 1a). -- (b) if successful continue with (3) -- (3) on commit we perform the actual (logical) delete of the nodes retryRes <- newIORef Nothing -- introduce IORef to communicate which retry led to abort next <- atomically $ (do r <- reVerifyAndSetFalse ns -- (1) case r of Just cnt -> do unsafeIOToSTM $ writeIORef retryRes (Just cnt) -- pass info to else branch, the continuation -- of the first failed verify field retry Nothing -> do r2 <- verifyAtomicGuard checkAtomicGuards -- (2) case r2 of Just cnt -> do unsafeIOToSTM $ writeIORef retryRes (Just cnt) -- pass info to else branch, continuation of -- the last field (need to continue search) retry Nothing -> do return (return (Just (do {accDeletes checkNodes; body}))) -- (3) ) `orElse` (do x <- unsafeIOToSTM $ readIORef retryRes case x of Nothing -> error "impossible" Just cnt -> return cnt) next {- -- Version2 (pure version): -- in the first transaction -- (i) we reverify the fields (setting to false comes later!) -- (a) in case of failure, collect the continuation -- and return (commit) -- (no retry necessary cause no setting to false yet) -- (b) if ok go to (ii) -- (ii) (a) verify atomic guards (with side-effects) -- (a) in case of failure, we retry -- then second transaction will select the continuation -- of the last atomic guard -- (b) if successful continue with (3) -- (3) set fields to false -- on commit we perform the actual (logical) delete of the nodes next <- atomically $ (do r <- reVerify ns -- (i) case r of Just cnt -> return cnt Nothing -> do r2 <- verifyAtomicGuard checkAtomicGuards -- (ii) case r2 of Just cnt -> retry Nothing -> do setFalse ns return (return (Just (do {accDeletes checkNodes; body}))) -- (iii) ) `orElse` (do let (AtomicGuardVerify _, cnt) = last checkAtomicGuards return cnt) next -} --getIndex :: Store msg -> msg -> IO HashIdx getIndex act m = return ((hashMsg (hashOp act)) m) --initSearch :: Store msg -> HashIdx -> IO (B.Iterator (InternalMsg msg)) initSearch act idx = do let bag = (msgTable act) !! (idx -1) t_id <- myThreadId let no = threadIdToInt t_id let bagEntryIdx = no `mod` distribution it <- B.newIterator bag bagEntryIdx return it -- we use the iterator to scan through the queue --nextMsg :: Store msg -> (B.Iterator (InternalMsg msg)) -> IO (Maybe (Location msg)) nextMsg act curIterator = do res <- B.iterateBag curIterator return res --extractMsg :: Location msg -> IO (Maybe (InternalMsg msg)) extractMsg ptr = do node <- readIORef ptr case node of L.Node {} -> return (Just (L.val node)) _ -> return Nothing printMsg _ ptr = do do m <- readIORef ptr return (show (L.val m)) printReachMsg _ it = error "TODO" -- HACK!!!!! -- FIX -- length "ThreadId " = 9 threadIdToInt x = read (drop 9 (show x)) :: Int newStore :: (EMatch msg, Eq msg, Show msg) => HashOp msg -> IO (Store msg) newStore hash = do let n = numberOfTables hash mt <- mapM (\ _ -> B.newBag (distribution-1)) [1..n] -- distribution starts with 0 !!! return (Store {msgTable = mt, hashOp = hash}) compileRulePattern :: (EMatch msg, Eq msg, Show msg) => [([MatchTask msg], Code_RHS ())] -> [CompClause (Store msg) (Location msg) ()] compileRulePattern prog = let build [] = [] build ((tasks,body):rest) = (compileCnt body tasks) ++ (build rest) in build prog -- adds the message in external format and -- returns (added) message in internal format -- this is the format we need to perform the search addMsg :: (EMatch msg, Eq msg, Show msg) => (Store msg) -> msg -> IO (Location msg) addMsg (Store {msgTable = mt, hashOp = hash}) msg = do new_tag <- newTag let new_msg = InternalMsg {message = msg, msg_tag = new_tag} let hashIdx = (hashMsg hash) msg let bag = mt !! (hashIdx - 1) t_id <- myThreadId let no = threadIdToInt t_id let bagEntryIdx = no `mod` distribution loc <- B.addToBag bag bagEntryIdx new_msg return loc executeRules :: (EMatch msg, Eq msg, Show msg) => Store msg -> Location msg -> [CompClause (Store msg) (Location msg) ()] -> IO (Maybe (Code_RHS ())) executeRules store active_msg prog = select store active_msg prog {- ----------------------------------- -- some old stuff ----------------------------------- --atomicVerifyAndDeleteCnt :: Store msg -> Code_RHS a -- -> [(Check (Location msg),IO (Maybe (Code_RHS a)))] -> IO (Maybe (Code_RHS a)) -- we don't need the store here, but otherwise the method's type is ambiguous atomicVerifyAndDeleteCnt _ body checks = let -- reverify that all verify fields are True reVerify [] = return True reVerify (n:ns) = do let n' = case n of Verify n -> n VerifyAndDelete n -> n b <- readTVar n' if b then reVerify ns else return False -- build Boolean conjunction of all atomic guards verifyAtomicGuard gs = do bs <- mapM (\g -> case g of AtomicGuardVerify g -> do b <- g return b _ -> error "impossible: verifyAtomicGuard") gs return (and bs) -- set verify fields to False -- only those which actually need to be deleted (the simp heads) setFalse [] = return () setFalse ((Verify _):ns) = setFalse ns setFalse ((VerifyAndDelete n):ns) = do writeTVar n False setFalse ns -- accumulates all deletes (only simp heads) accDeletes [] = return () accDeletes ((Verify _,_):ns) = accDeletes ns accDeletes ((VerifyAndDelete msg,_):ns) = do node <- readIORef msg writeIORef msg (L.DelNode {L.verify = L.verify node, L.next = L.next node}) accDeletes ns -- in case of failure, pick the continuation of the node -- which failed (the earliest from left to right) checkNode (msg,cnt) = do node <- readIORef msg b <- atomically $ readTVar (L.verify node) if b then return Nothing else return (Just cnt) pickCont [] = error "pickCont: impossible, there must be a failed node" pickCont (c:rest) = do let (msg,cnt) = case c of (Verify msg, cnt) -> (msg, cnt) (VerifyAndDelete msg, cnt) -> (msg, cnt) res <- checkNode (msg,cnt) case res of Nothing -> pickCont rest Just cnt -> cnt selectNode = \n -> case n of Verify _ -> True VerifyAndDelete -> True _ -> False checkNodes = filter selectNode checks -- select to be verified nodes checkAtomicGuards = filter (not.nodeCheck) checks -- select the atomic guards (those with side-effects) -- side-effect guards have already been check earlier in do ns <- -- extract the to be verified fields mapM (\ (m,_) -> case m of Verify msg -> do node <- readIORef msg return (Verify (L.verify node)) VerifyAndDelete msg -> do node <- readIORef msg return (VerifyAndDelete (L.verify node))) checkNodes -- perform atomic re-verification -- check that nodes are still there and -- check that atomic guards are true, if successful -- set node flags to False -- we continue by actually deleting the nodes followed by -- executing the body -- otherwise, we abort and -- (1) either pick the continuation of the -- first node which couldn't be reverified (back-jumping!) -- (2) if all nodes could be verified but the atomic guard caused failure -- pick the continuation of the last node next <- atomically $ (do r <- reVerify ns r2 <- verifyAtomicGuarad checkAtomicGuards if (r && r2) then do setFalse ns return (return (Just (do {accDeletes checks; body}))) else retry ) `orElse` return (pickCont checks) next -}