tapdb+universe: add SpentCommitment to RootCommitment

To find out what commitment is being spent by a next one, we add the
optional SpentCommitment field to the RootCommitment struct.
The field should only be None for the very first commitment of an asset
group.

Author: guggero

tapdb/sqlc/querier.go

@@ -165,6 +165,13 @@ FROM supply_commitments AS sc
     ON sc.chain_txn_id = ct.txn_id
 WHERE sc.spent_commitment = (SELECT commit_id FROM spent_commitment);
 
+-- name: QuerySupplyCommitmentOutpoint :one
+SELECT ct.txid, sc.output_index
+FROM supply_commitments AS sc
+    JOIN chain_txns AS ct
+    ON sc.chain_txn_id = ct.txn_id
+WHERE sc.commit_id = @commit_id;
+
 -- name: UpdateSupplyCommitTransitionCommitment :exec
 UPDATE supply_commit_transitions
 SET new_commitment_id = @new_commitment_id,

tapdb/sqlc/queries/supply_commit.sql

@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"github.com/btcsuite/btcd/btcec/v2"
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightninglabs/taproot-assets/asset"
 	"github.com/lightninglabs/taproot-assets/fn"
@@ -189,6 +190,11 @@ type SupplyCommitStore interface {
 		arg sqlc.QuerySupplyCommitmentBySpentOutpointParams) (
 		sqlc.QuerySupplyCommitmentBySpentOutpointRow, error)
 
+	// QuerySupplyCommitmentOutpoint fetches the outpoint of a supply
+	// commitment by its ID.
+	QuerySupplyCommitmentOutpoint(ctx context.Context,
+		commitID int64) (sqlc.QuerySupplyCommitmentOutpointRow, error)
+
 	// FetchChainTx fetches a chain transaction by its TXID.
 	FetchChainTx(ctx context.Context, txid []byte) (ChainTxn, error)
 
@@ -1194,6 +1200,30 @@ func parseSupplyCommitmentRow(ctx context.Context, commit SupplyCommitment,
 		}
 	}
 
+	if commit.SpentCommitment.Valid {
+		spentRow, err := db.QuerySupplyCommitmentOutpoint(
+			ctx, commit.SpentCommitment.Int64,
+		)
+		if err != nil {
+			return nil, fmt.Errorf("failed to query spent "+
+				"commitment with ID %d for commit %d: %w",
+				commit.SpentCommitment.Int64, commit.CommitID,
+				err)
+		}
+
+		hash, err := chainhash.NewHash(spentRow.Txid)
+		if err != nil {
+			return nil, fmt.Errorf("failed to parse spent "+
+				"commitment txid %x for commit %d: %w",
+				spentRow.Txid, commit.CommitID, err)
+		}
+
+		rootCommitment.SpentCommitment = fn.Some(wire.OutPoint{
+			Hash:  *hash,
+			Index: uint32(spentRow.OutputIndex.Int32),
+		})
+	}
+
 	return rootCommitment, nil
 }
 

tapdb/sqlc/supply_commit.sql.go

@@ -308,6 +308,11 @@ type RootCommitment struct {
 	// asset supply. This may be None if the commitment has not yet
 	// been mined.
 	CommitmentBlock fn.Option[CommitmentBlock]
+
+	// SpentCommitment is the outpoint of the previous root commitment that
+	// this root commitment is spending. This will be None if this is the
+	// first root commitment for the asset.
+	SpentCommitment fn.Option[wire.OutPoint]
 }
 
 // TxIn returns the transaction input that corresponds to the root commitment.