From ce888ed941af9f614d506da3c72d1456f2dd4268 Mon Sep 17 00:00:00 2001
From: Wilmer Paulino <wilmer.paulino@gmail.com>
Date: Wed, 13 May 2020 08:54:23 -0700
Subject: [PATCH] wallet: use GetBlockHeaderVerbose to retrieve block heights
 in GetTransactions

There's no need to retrieve the full block as we're only interesting in
retrieve its corresponding height, which can be done with
GetBlockHeaderVerbose.
---
 wallet/wallet.go | 38 ++++++++++++++++++++------------------
 1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/wallet/wallet.go b/wallet/wallet.go
index cf2990f..ad16ab9 100644
--- a/wallet/wallet.go
+++ b/wallet/wallet.go
@@ -20,7 +20,6 @@ import (
 	"github.com/btcsuite/btcd/btcjson"
 	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
-	"github.com/btcsuite/btcd/rpcclient"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
@@ -2202,7 +2201,6 @@ func (w *Wallet) GetTransactions(startBlock, endBlock *BlockIdentifier, cancel <
 	// TODO: Fetching block heights by their hashes is inherently racy
 	// because not all block headers are saved but when they are for SPV the
 	// db can be queried directly without this.
-	var startResp, endResp rpcclient.FutureGetBlockVerboseResult
 	if startBlock != nil {
 		if startBlock.hash == nil {
 			start = startBlock.height
@@ -2212,7 +2210,13 @@ func (w *Wallet) GetTransactions(startBlock, endBlock *BlockIdentifier, cancel <
 			}
 			switch client := chainClient.(type) {
 			case *chain.RPCClient:
-				startResp = client.GetBlockVerboseTxAsync(startBlock.hash)
+				startHeader, err := client.GetBlockHeaderVerbose(
+					startBlock.hash,
+				)
+				if err != nil {
+					return nil, err
+				}
+				start = startHeader.Height
 			case *chain.BitcoindClient:
 				var err error
 				start, err = client.GetBlockHeight(startBlock.hash)
@@ -2237,7 +2241,19 @@ func (w *Wallet) GetTransactions(startBlock, endBlock *BlockIdentifier, cancel <
 			}
 			switch client := chainClient.(type) {
 			case *chain.RPCClient:
-				endResp = client.GetBlockVerboseTxAsync(endBlock.hash)
+				endHeader, err := client.GetBlockHeaderVerbose(
+					endBlock.hash,
+				)
+				if err != nil {
+					return nil, err
+				}
+				end = endHeader.Height
+			case *chain.BitcoindClient:
+				var err error
+				start, err = client.GetBlockHeight(endBlock.hash)
+				if err != nil {
+					return nil, err
+				}
 			case *chain.NeutrinoClient:
 				var err error
 				end, err = client.GetBlockHeight(endBlock.hash)
@@ -2247,20 +2263,6 @@ func (w *Wallet) GetTransactions(startBlock, endBlock *BlockIdentifier, cancel <
 			}
 		}
 	}
-	if startResp != nil {
-		resp, err := startResp.Receive()
-		if err != nil {
-			return nil, err
-		}
-		start = int32(resp.Height)
-	}
-	if endResp != nil {
-		resp, err := endResp.Receive()
-		if err != nil {
-			return nil, err
-		}
-		end = int32(resp.Height)
-	}
 
 	var res GetTransactionsResult
 	err := walletdb.View(w.db, func(dbtx walletdb.ReadTx) error {