PerasWeightSnapshot: minimize API

Author: amesgen

ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Peras/Weight.hs

@@ -12,7 +12,7 @@ module Ouroboros.Consensus.Peras.Weight
   , mkPerasWeightSnapshot
   , perasWeightSnapshotToList
   , addToPerasWeightSnapshot
-  , removeFromPerasWeightSnapshot
+  , prunePerasWeightSnapshot
   , weightBoostOfPoint
   , weightBoostOfFragment
   ) where
@@ -57,19 +57,15 @@ addToPerasWeightSnapshot ::
 addToPerasWeightSnapshot pt weight =
   PerasWeightSnapshot . Map.insertWith (<>) pt weight . getPerasWeightSnapshot
 
-removeFromPerasWeightSnapshot ::
-  StandardHash blk =>
-  Point blk ->
-  PerasWeight ->
+prunePerasWeightSnapshot ::
+  SlotNo ->
   PerasWeightSnapshot blk ->
   PerasWeightSnapshot blk
-removeFromPerasWeightSnapshot pt (PerasWeight weight) =
-  PerasWeightSnapshot . Map.update subtractWeight pt . getPerasWeightSnapshot
+prunePerasWeightSnapshot slot =
+  PerasWeightSnapshot . Map.dropWhileAntitone isTooOld . getPerasWeightSnapshot
  where
-  subtractWeight :: PerasWeight -> Maybe PerasWeight
-  subtractWeight (PerasWeight w)
-    | w > weight = Just $ PerasWeight (w - weight)
-    | otherwise = Nothing
+  isTooOld :: Point blk -> Bool
+  isTooOld pt = pointSlot pt < NotOrigin slot
 
 weightBoostOfPoint ::
   forall blk.

ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/PerasCertDB/Impl.hs

@@ -21,7 +21,6 @@ module Ouroboros.Consensus.Storage.PerasCertDB.Impl
   ) where
 
 import Control.Tracer (Tracer, nullTracer, traceWith)
-import Data.Foldable as Foldable (foldl')
 import Data.Kind (Type)
 import Data.Map.Strict (Map)
 import qualified Data.Map.Strict as Map
@@ -201,19 +200,10 @@ implGarbageCollect PerasCertDbEnv{pcdbVolatileState} slot =
   gc PerasVolatileCertState{pvcsCerts, pvcsWeightByPoint} =
     PerasVolatileCertState
       { pvcsCerts = certsToKeep
-      , pvcsWeightByPoint =
-          Foldable.foldl'
-            ( \s cert ->
-                removeFromPerasWeightSnapshot
-                  (perasCertBoostedBlock cert)
-                  boostPerCert
-                  s
-            )
-            pvcsWeightByPoint
-            certsToRemove
+      , pvcsWeightByPoint = prunePerasWeightSnapshot slot pvcsWeightByPoint
       }
    where
-    (certsToRemove, certsToKeep) =
+    (_, certsToKeep) =
       Map.partition isTooOld pvcsCerts
     isTooOld cert =
       pointSlot (perasCertBoostedBlock cert) < NotOrigin slot