Rename History to Rearview

I like colorful names

lib/core/src/Cardano/Wallet/Network.hs

@@ -30,7 +30,7 @@ module Cardano.Wallet.Network
 
     -- * Logging (for testing)
     , FollowStats (..)
-    , History (..)
+    , Rearview (..)
     , emptyStats
     , updateStats
     ) where
@@ -335,7 +335,7 @@ instance HasSeverityAnnotation (ChainSyncLog block point) where
 -- Includes computed statistics about synchronization progress.
 data ChainFollowLog
     = MsgChainSync (ChainSyncLog BlockHeader ChainPoint)
-    | MsgFollowStats (FollowStats History)
+    | MsgFollowStats (FollowStats Rearview)
     | MsgStartFollowing
     deriving (Show, Eq, Generic)
 
@@ -357,7 +357,7 @@ instance HasSeverityAnnotation ChainFollowLog where
 -------------------------------------------------------------------------------}
 -- | Statistics of interest from the follow-function.
 --
--- The @f@ allows us to use 'History' to keep track of both current and
+-- The @f@ allows us to use 'Rearview' to keep track of both current and
 -- previously logged stats, and perform operations over it in a nice way.
 data FollowStats f = FollowStats
     { blocksApplied :: !(f Int)
@@ -372,11 +372,11 @@ data FollowStats f = FollowStats
 -- It seems UTCTime contains thunks internally. This shouldn't matter as we
 -- 1. Change it seldom - from @flush@, not from @updateStats@
 -- 2. Set to a completely new value when we do change it.
-deriving via (AllowThunksIn '["time"] (FollowStats History))
-    instance (NoThunks (FollowStats History))
+deriving via (AllowThunksIn '["time"] (FollowStats Rearview))
+    instance (NoThunks (FollowStats Rearview))
 
-deriving instance Show (FollowStats History)
-deriving instance Eq (FollowStats History)
+deriving instance Show (FollowStats Rearview)
+deriving instance Eq (FollowStats Rearview)
 
 -- | Change the @f@ wrapping each record field.
 hoistStats
@@ -386,37 +386,37 @@ hoistStats
 hoistStats f (FollowStats a b c d e) =
     FollowStats (f a) (f b) (f c) (f d) (f e)
 
--- | A 'History' consists of a past value and a present value.
+-- | A 'Rearview' consists of a past value and a present value.
 -- Useful for keeping track of past logs.
 --
 -- The idea is to
 -- 1. Reconstruct a model of the @current@ @state@ using a @Trace@
 -- 2. Sometimes log the difference between the @current@ state and the most
 -- recently logged one.
-data History a = History
+data Rearview a = Rearview
     { past :: !a -- ^ Most previously logged state
     , current :: !a -- ^ Not-yet logged state
     } deriving (Eq, Show, Functor, Generic)
 
-instance NoThunks a => NoThunks (History a)
+instance NoThunks a => NoThunks (Rearview a)
 
-initHistory :: a -> History a
-initHistory a = History a a
+initRearview :: a -> Rearview a
+initRearview a = Rearview a a
 
--- | Modify the present state of a @History state@
-overCurrent :: (a -> a) -> History a -> History a
-overCurrent f (History pas cur) = History pas (f cur)
+-- | Modify the present state of a @Rearview state@
+overCurrent :: (a -> a) -> Rearview a -> Rearview a
+overCurrent f (Rearview pas cur) = Rearview pas (f cur)
 
-emptyStats :: UTCTime -> FollowStats History
+emptyStats :: UTCTime -> FollowStats Rearview
 emptyStats t = FollowStats (f 0) (f 0) (f ChainPointAtGenesis) (f t) (f p)
   where
-    f = initHistory
+    f = initRearview
     p = NotResponding -- Hijacked as an initial value for simplicity.
 
 -- | Update the current statistics based on a new log message.
 updateStats
     :: ChainSyncLog block ChainPoint
-    -> FollowStats History -> FollowStats History
+    -> FollowStats Rearview -> FollowStats Rearview
 updateStats msg s = case msg of
     MsgChainRollForward blocks _tip ->
         s { blocksApplied = overCurrent (+ NE.length blocks) (blocksApplied s) }
@@ -427,24 +427,24 @@ updateStats msg s = case msg of
         s { localTip = overCurrent (const point) (localTip s) }
     _ -> s
 
-instance ToText (FollowStats History) where
+instance ToText (FollowStats Rearview) where
     toText st@(FollowStats b r tip t progress) =
         syncStatus <> " " <> stats <> sevExpl
       where
         syncStatus = case progress of
-            History NotResponding Ready ->
+            Rearview NotResponding Ready ->
                 "In sync."
-            History Ready Ready ->
+            Rearview Ready Ready ->
                 "Still in sync."
-            History NotResponding NotResponding ->
+            Rearview NotResponding NotResponding ->
                 "Still not syncing."
-            History (Syncing _p) Ready ->
+            Rearview (Syncing _p) Ready ->
                 "In sync!"
-            History Ready (Syncing p) ->
+            Rearview Ready (Syncing p) ->
                 "Fell out of sync (" <> (pretty p) <> ")"
-            History _ (Syncing p) ->
+            Rearview _ (Syncing p) ->
                 "Syncing (" <> (pretty p) <> ")"
-            History past_ NotResponding ->
+            Rearview past_ NotResponding ->
                 "Not responding. Previously " <> (pretty past_) <> "."
         stats = mconcat
             [ "Applied " <> pretty (using (-) b) <> " blocks, "
@@ -466,7 +466,7 @@ instance ToText (FollowStats History) where
 -- But this check might be in the wrong place. Might be better to
 -- produce new logs from inside the updateStats function and immeditely
 -- warn there.
-explainedSeverityAnnotation :: FollowStats History -> (Severity, Maybe Text)
+explainedSeverityAnnotation :: FollowStats Rearview -> (Severity, Maybe Text)
 explainedSeverityAnnotation s
     | progressMovedBackwards = (Warning, Just "progress decreased")
     | noBlocks && notRestored = (Warning, Just "not applying blocks")
@@ -478,17 +478,17 @@ explainedSeverityAnnotation s
     notRestored = current (prog s) /= Ready
     noBlocks = (current (blocksApplied s) - past (blocksApplied s)) <= 0
 
-instance HasSeverityAnnotation (FollowStats History) where
+instance HasSeverityAnnotation (FollowStats Rearview) where
     getSeverityAnnotation = fst . explainedSeverityAnnotation
 
--- | Update the 'TMVar' holding the 'FollowStats'@ @'History'
+-- | Update the 'TMVar' holding the 'FollowStats'@ @'Rearview'
 -- to forget the 'past' values and replace them with the 'current' ones.
 -- Also update the time and sync process.
 flushStats
     :: UTCTime
     -> (SlotNo -> IO SyncProgress)
-    -> StrictTMVar IO (FollowStats History)
-    -> IO (FollowStats History)
+    -> StrictTMVar IO (FollowStats Rearview)
+    -> IO (FollowStats Rearview)
 flushStats t calcSyncProgress var = do
     s <- atomically $ takeTMVar var
     p <- calcSyncProgress $ pseudoPointSlot $ current $ localTip s
@@ -497,7 +497,7 @@ flushStats t calcSyncProgress var = do
     atomically $ putTMVar var $ hoistStats forgetPast s'
     return s'
   where
-    forgetPast (History _past curr) = initHistory curr
+    forgetPast (Rearview _past curr) = initRearview curr
 
     -- See NOTE [PointSlotNo].
     -- Fortunately, this is not important for the use here.