Establish host properties and isolated kind matrix

src/Nuthatch/Protocol.hs

@@ -13,6 +13,11 @@ module Nuthatch.Protocol
   , claimActiveBatch
   , lookupMutation
   , lookupObjectMeta
+  , sameFingerprint
+  , growthBytes
+  , quotaAllows
+  , terminalExpiryEligible
+  , recoveryEligible
   , desiredMatches
   , priorMatches
   ) where
@@ -105,6 +110,21 @@ sameFingerprint rec kind key size msha =
     && mrDeclaredSize rec == size
     && mrContentSha256 rec == msha
 
+growthBytes :: Integer -> Integer -> Integer
+growthBytes priorSize desiredSize = max 0 (desiredSize - priorSize)
+
+quotaAllows :: Integer -> Integer -> Integer -> Integer -> Bool
+quotaAllows limitBytes usedBytes reservedBytes growth =
+  usedBytes + reservedBytes + growth <= limitBytes
+
+terminalExpiryEligible :: MutationState -> ExternalState -> Bool
+terminalExpiryEligible state external =
+  state `elem` [Succeeded, Failed, Rejected] && external == ExtIdle
+
+recoveryEligible :: MutationState -> Integer -> Integer -> Bool
+recoveryEligible state elapsedSeconds graceSeconds =
+  state `elem` [Prepared, Applying] && elapsedSeconds > graceSeconds
+
 admitMutation
   :: Connection
   -> UserId
@@ -131,7 +151,7 @@ admitMutation conn uid kind op pool key rel size msha maxObject = do
           desiredSize = case kind of
             Put    -> size
             Delete -> 0
-          growth = max 0 (desiredSize - priorSize)
+          growth = growthBytes priorSize desiredSize
           baseRec state =
             MutationRecord
               { mrUserId = uid
@@ -416,13 +436,12 @@ desiredMatches rec = \case
       Put    -> False
   ObjectPresent sz msha ->
     case mrKind rec of
-      Delete -> sz == 0
+      Delete -> False
       Put ->
         sz == mrDeclaredSize rec
           && case (mrContentSha256 rec, msha) of
                (Just want, Just got) -> want == got
-               -- Some stores omit custom metadata on HEAD.
-               (Just _, Nothing)     -> True
+               (Just _, Nothing)     -> False
                (Nothing, _)          -> True
 
 priorMatches :: MutationRecord -> ObjectObservation -> Bool