From dc51d2219b42bd38462de4feb45020e348062a6b Mon Sep 17 00:00:00 2001
From: Hongrui Fang <chfanghr@gmail.com>
Date: Thu, 26 Jan 2023 22:35:39 +0800
Subject: [PATCH] allow effect datum to be stored inline

---
 agora/Agora/Governor/Scripts.hs | 13 +++++++++----
 agora/Agora/Utils.hs            | 24 ++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/agora/Agora/Governor/Scripts.hs b/agora/Agora/Governor/Scripts.hs
index 15a76eb..8c63101 100644
--- a/agora/Agora/Governor/Scripts.hs
+++ b/agora/Agora/Governor/Scripts.hs
@@ -41,7 +41,7 @@ import Agora.Stake (
   pnumCreatedProposals,
   presolveStakeInputDatum,
  )
-import Agora.Utils (ptaggedSymbolValueOf, ptoScottEncodingT, puntag)
+import Agora.Utils (phashDatum, ptaggedSymbolValueOf, ptoScottEncodingT, puntag)
 import Data.Function (on)
 import Plutarch.Api.V1 (PCurrencySymbol)
 import Plutarch.Api.V1.AssocMap (plookup)
@@ -54,6 +54,7 @@ import Plutarch.Api.V2 (
   PTxOutRef,
   PValidator,
  )
+import Plutarch.Api.V2.Tx (POutputDatum (..))
 import Plutarch.Extra.AssetClass (PAssetClassData, passetClass)
 import Plutarch.Extra.Field (pletAll, pletAllC)
 import Plutarch.Extra.Maybe (passertPJust, pfromJust, pjust, pmaybeData, pnothing)
@@ -64,7 +65,6 @@ import Plutarch.Extra.ScriptContext (
   pisUTXOSpent,
   pscriptHashFromAddress,
   pscriptHashToTokenName,
-  ptryFromDatumHash,
   ptryFromOutputDatum,
   pvalueSpent,
  )
@@ -541,8 +541,13 @@ governorValidator =
                                     # outputF.value
                                     #== 1
 
-                            let hasCorrectDatum =
-                                  effect.datumHash #== ptryFromDatumHash # outputF.datum
+                            let outputDatumHash = pmatch outputF.datum $ \case
+                                  POutputDatum d -> phashDatum # d
+                                  POutputDatumHash h -> pfield @"datumHash" # h
+                                  _ -> ptraceError "expcted effect datum, got nothing"
+
+                                hasCorrectDatum =
+                                  effect.datumHash #== outputDatumHash
 
                             pguardC "Authority output valid" $
                               foldr1
diff --git a/agora/Agora/Utils.hs b/agora/Agora/Utils.hs
index 1f50e50..17e70f7 100644
--- a/agora/Agora/Utils.hs
+++ b/agora/Agora/Utils.hs
@@ -17,8 +17,10 @@ module Agora.Utils (
   ptaggedSymbolValueOf,
   ptag,
   puntag,
+  phashDatum,
 ) where
 
+import Plutarch.Api.V1.Scripts (PDatumHash (PDatumHash))
 import Plutarch.Api.V2 (
   AmountGuarantees,
   KeyGuarantees,
@@ -26,6 +28,8 @@ import Plutarch.Api.V2 (
   PMaybeData (PDNothing),
   PValue,
  )
+import Plutarch.Builtin (pforgetData, pserialiseData)
+import Plutarch.Crypto (pblake2b_256)
 import Plutarch.Extra.AssetClass (PAssetClass, PAssetClassData, ptoScottEncoding)
 import Plutarch.Extra.Tagged (PTagged)
 import Plutarch.Extra.Value (psymbolValueOf)
@@ -115,3 +119,23 @@ puntag ::
   Term s (PTagged tag a) ->
   Term s a
 puntag = pto
+
+{- | Hash the given datum using the correct algorithm(blake2b_256).
+
+     Note: check the discussion here: https://github.com/input-output-hk/cardano-ledger/issues/2941.
+
+     @since 1.0.0
+-}
+phashDatum ::
+  forall (a :: PType) (s :: S).
+  PIsData a =>
+  Term s (a :--> PDatumHash)
+phashDatum =
+  phoistAcyclic $
+    plam $
+      pcon
+        . PDatumHash
+        . (pblake2b_256 #)
+        . (pserialiseData #)
+        . pforgetData
+        . pdata