types,consensus: Add V2ClaimOutputID

consensus/update.go

@@ -503,7 +503,7 @@ func (ms *MidState) ApplyV2Transaction(txn types.V2Transaction) {
 		ms.spendSiafundElement(sfi.Parent, txid)
 		claimPortion := ms.siafundPool.Sub(sfi.Parent.ClaimStart).Div64(ms.base.SiafundCount()).Mul64(sfi.Parent.SiafundOutput.Value)
 		ms.addSiacoinElement(types.SiacoinElement{
-			StateElement:   types.StateElement{ID: types.Hash256(types.SiafundOutputID(sfi.Parent.ID).ClaimOutputID())},
+			StateElement:   types.StateElement{ID: types.Hash256(types.SiafundOutputID(sfi.Parent.ID).V2ClaimOutputID())},
 			SiacoinOutput:  types.SiacoinOutput{Value: claimPortion, Address: sfi.ClaimAddress},
 			MaturityHeight: ms.base.MaturityHeight(),
 		})

types/types.go

@@ -221,6 +221,17 @@ func (sfoid SiafundOutputID) ClaimOutputID() SiacoinOutputID {
 	return SiacoinOutputID(HashBytes(sfoid[:]))
 }
 
+// V2ClaimOutputID returns the ID of the SiacoinOutput that is created when the
+// siafund output is spent.
+func (sfoid SiafundOutputID) V2ClaimOutputID() SiacoinOutputID {
+	h := hasherPool.Get().(*Hasher)
+	defer hasherPool.Put(h)
+	h.Reset()
+	h.WriteDistinguisher("id/siacoinclaimoutput")
+	sfoid.EncodeTo(h.E)
+	return SiacoinOutputID(h.Sum())
+}
+
 // A SiafundInput spends an unspent SiafundOutput in the UTXO set by revealing
 // and satisfying its unlock conditions. SiafundInputs also include a
 // ClaimAddress, specifying the recipient of the siacoins that were earned by