chaintopology: Refactor get_tx_depth to use the DB backed tx store

We are slowly hollowing out the in-memory blockchain representation to make
restarts easier.

Signed-off-by: Christian Decker <decker.christian@gmail.com>

lightningd/chaintopology.c

@@ -127,15 +127,13 @@ static struct block *block_for_tx(const struct chain_topology *topo,
 }
 
 size_t get_tx_depth(const struct chain_topology *topo,
-		    const struct bitcoin_txid *txid,
+		    const struct bitcoin_txid *txid)
-		    const struct bitcoin_tx **tx)
 {
-	const struct block *b;
+	u32 blockheight = wallet_transaction_height(topo->wallet, txid);
 
-	b = block_for_tx(topo, txid, tx);
+	if (blockheight == 0)
-	if (!b)
 		return 0;
-	return topo->tip->height - b->height + 1;
+	return topo->tip->height - blockheight + 1;
 }
 
 struct txs_to_broadcast {

lightningd/chaintopology.h

@@ -129,10 +129,9 @@ struct txlocator {
 };
 
 /* This is the number of blocks which would have to be mined to invalidate
- * the tx (optional tx is filled in if return is non-zero). */
+ * the tx */
 size_t get_tx_depth(const struct chain_topology *topo,
-		    const struct bitcoin_txid *txid,
+		    const struct bitcoin_txid *txid);
-		    const struct bitcoin_tx **tx);
 
 /* Get highest block number. */
 u32 get_block_height(const struct chain_topology *topo);

lightningd/watch.c

@@ -281,9 +281,8 @@ again:
 	     w;
 	     w = txwatch_hash_next(&topo->txwatches, &i)) {
 		u32 depth;
-		const struct bitcoin_tx *tx;
 
-		depth = get_tx_depth(topo, &w->txid, &tx);
+		depth = get_tx_depth(topo, &w->txid);
 		if (depth)
 			needs_rerun |= txw_fire(w, &w->txid, depth);
 	}