wallet: Avoid use of Chain::Lock in rescanblockchain

This is a step toward removing the Chain::Lock class and reducing cs_main
locking.

This change only affects behavior in the case where wallet last block processed
falls behind the chain tip. The rescanblockchain error height error checking
will just be stricter in this case and only accept values up to the last
processed height

1 files changed, 8 insertions, 7 deletions

diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 9ffb810ee7..70d39a8fc5 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -1615,9 +1615,8 @@ int64_t CWallet::RescanFromTime(int64_t startTime, const WalletRescanReserver& r
  *
  * @param[in] start_block Scan starting block. If block is not on the active
  *                        chain, the scan will return SUCCESS immediately.
- * @param[in] stop_block  Scan ending block. If block is not on the active
- *                        chain, the scan will continue until it reaches the
- *                        chain tip.
+ * @param[in] max_height  Optional max scanning height. If unset there is
+ *                        no maximum and scanning can continue to the tip
  *
  * @return ScanResult returning scan information and indicating success or
  *         failure. Return status will be set to SUCCESS if scan was
@@ -1629,7 +1628,7 @@ int64_t CWallet::RescanFromTime(int64_t startTime, const WalletRescanReserver& r
  * the main chain after to the addition of any new keys you want to detect
  * transactions for.
  */
-CWallet::ScanResult CWallet::ScanForWalletTransactions(const uint256& start_block, const uint256& stop_block, const WalletRescanReserver& reserver, bool fUpdate)
+CWallet::ScanResult CWallet::ScanForWalletTransactions(const uint256& start_block, Optional<int> max_height, const WalletRescanReserver& reserver, bool fUpdate)
 {
     int64_t nNow = GetTime();
     int64_t start_time = GetTimeMillis();
@@ -1654,8 +1653,10 @@ CWallet::ScanResult CWallet::ScanForWalletTransactions(const uint256& start_bloc
             tip_hash = locked_chain->getBlockHash(*tip_height);
         }
         block_height = locked_chain->getBlockHeight(block_hash);
+        uint256 end_hash = tip_hash;
+        if (max_height) chain().findAncestorByHeight(tip_hash, *max_height, FoundBlock().hash(end_hash));
         progress_begin = chain().guessVerificationProgress(block_hash);
-        progress_end = chain().guessVerificationProgress(stop_block.IsNull() ? tip_hash : stop_block);
+        progress_end = chain().guessVerificationProgress(end_hash);
     }
     double progress_current = progress_begin;
     while (block_height && !fAbortRescan && !chain().shutdownRequested()) {
@@ -1693,7 +1694,7 @@ CWallet::ScanResult CWallet::ScanForWalletTransactions(const uint256& start_bloc
             result.last_failed_block = block_hash;
             result.status = ScanResult::FAILURE;
         }
-        if (block_hash == stop_block) {
+        if (max_height && *block_height >= *max_height) {
             break;
         }
         {
@@ -1712,7 +1713,7 @@ CWallet::ScanResult CWallet::ScanForWalletTransactions(const uint256& start_bloc
             // handle updated tip hash
             const uint256 prev_tip_hash = tip_hash;
             tip_hash = locked_chain->getBlockHash(*tip_height);
-            if (stop_block.IsNull() && prev_tip_hash != tip_hash) {
+            if (!max_height && prev_tip_hash != tip_hash) {
                 // in case the tip has changed, update progress max
                 progress_end = chain().guessVerificationProgress(tip_hash);
             }