use TList for ChangePool

Assistant/Changes.hs

@@ -1,6 +1,6 @@
 {- git-annex assistant change tracking
  -
- - Copyright 2012 Joey Hess <joey@kitenet.net>
+ - Copyright 2012-2013 Joey Hess <joey@kitenet.net>
  -
  - Licensed under the GNU GPL version 3 or higher.
  -}
@@ -9,7 +9,7 @@ module Assistant.Changes where
 
 import Assistant.Common
 import Assistant.Types.Changes
-import Utility.TSet
+import Utility.TList
 
 import Data.Time.Clock
 import Control.Concurrent.STM
@@ -28,17 +28,17 @@ pendingAddChange f = Just <$> (PendingAddChange <$> liftIO getCurrentTime <*> pu
 {- Gets all unhandled changes.
  - Blocks until at least one change is made. -}
 getChanges :: Assistant [Change]
-getChanges = fmap concat $ (atomically . getTSet) <<~ changeChan
+getChanges = (atomically . getTList) <<~ changePool
 
 {- Gets all unhandled changes, without blocking. -}
 getAnyChanges :: Assistant [Change]
-getAnyChanges = fmap concat $ (atomically . readTSet) <<~ changeChan
+getAnyChanges = (atomically . readTList) <<~ changePool
 
-{- Puts unhandled changes back into the channel.
+{- Puts unhandled changes back into the pool.
  - Note: Original order is not preserved. -}
 refillChanges :: [Change] -> Assistant ()
-refillChanges cs = (atomically . flip putTSet1 cs) <<~ changeChan
+refillChanges cs = (atomically . flip appendTList cs) <<~ changePool
 
-{- Records a change in the channel. -}
+{- Records a change to the pool. -}
 recordChange :: Change -> Assistant ()
-recordChange c = (atomically . flip putTSet1 [c]) <<~ changeChan
+recordChange c = (atomically . flip snocTList c) <<~ changePool

Assistant/Monad.hs

@@ -66,7 +66,7 @@ data AssistantData = AssistantData
 	, transferrerPool :: TransferrerPool
 	, failedPushMap :: FailedPushMap
 	, commitChan :: CommitChan
-	, changeChan :: ChangeChan
+	, changePool :: ChangePool
 	, branchChangeHandle :: BranchChangeHandle
 	, buddyList :: BuddyList
 	, netMessager :: NetMessager
@@ -83,7 +83,7 @@ newAssistantData st dstatus = AssistantData
 	<*> newTransferrerPool
 	<*> newFailedPushMap
 	<*> newCommitChan
-	<*> newChangeChan
+	<*> newChangePool
 	<*> newBranchChangeHandle
 	<*> newBuddyList
 	<*> newNetMessager

Assistant/Types/Changes.hs

@@ -1,6 +1,6 @@
 {- git-annex assistant change tracking
  -
- - Copyright 2012 Joey Hess <joey@kitenet.net>
+ - Copyright 2012-2013 Joey Hess <joey@kitenet.net>
  -
  - Licensed under the GNU GPL version 3 or higher.
  -}
@@ -9,23 +9,22 @@ module Assistant.Types.Changes where
 
 import Types.KeySource
 import Types.Key
-import Utility.TSet
+import Utility.TList
 
-import Data.Time.Clock
 import Control.Concurrent.STM
+import Data.Time.Clock
 
-data ChangeInfo = AddKeyChange Key | AddFileChange | LinkChange (Maybe Key) | RmChange
-	deriving (Show, Eq)
+{- An un-ordered pool of Changes that have been noticed and should be
+ - staged and committed. Changes will typically be in order, but ordering
+ - may be lost. In any case, order should not matter, as any given Change
+ - may later be reverted by a later Change (ie, a file is added and then
+ - deleted). Code that processes the changes needs to deal with such
+ - scenarios.
+ -}
+type ChangePool = TList Change
 
-changeInfoKey :: ChangeInfo -> Maybe Key
-changeInfoKey (AddKeyChange k) = Just k
-changeInfoKey (LinkChange (Just k)) = Just k
-changeInfoKey _ = Nothing
-
-type ChangeChan = TSet [Change]
-
-newChangeChan :: IO ChangeChan
-newChangeChan = atomically newTSet
+newChangePool :: IO ChangePool
+newChangePool = atomically newTList
 
 data Change
 	= Change 
@@ -43,6 +42,14 @@ data Change
 		}
 	deriving (Show)
 
+data ChangeInfo = AddKeyChange Key | AddFileChange | LinkChange (Maybe Key) | RmChange
+	deriving (Show, Eq, Ord)
+
+changeInfoKey :: ChangeInfo -> Maybe Key
+changeInfoKey (AddKeyChange k) = Just k
+changeInfoKey (LinkChange (Just k)) = Just k
+changeInfoKey _ = Nothing
+
 changeFile :: Change -> FilePath
 changeFile (Change _ f _) = f
 changeFile (PendingAddChange _ f) = f