Merge #10412: Improve wallet rescan API

deaf48b Handle TIMESTAMP_WINDOW within CWallet::RescanFromTime (Russell Yanofsky)
5b2be2b Make CWallet::RescanFromTime comment less ambiguous (Russell Yanofsky)
9bb66ab Add RescanFromTime method and use from rpcdump (Russell Yanofsky)
ccf84bb Move birthday optimization out of ScanForWalletTransactions (Russell Yanofsky)

Tree-SHA512: cd38433b8f5c5e44ecfba830a6a26bd9a9d0f4a22ae42bce17773d1a6fb25e1ee4289484996dad2d7acfa03059917ff062459f25030a761da7083ba5fbc87bc9

3 files changed, 51 insertions, 22 deletions

diff --git a/src/wallet/rpcdump.cpp b/src/wallet/rpcdump.cpp
index 09aaf4f747..0fe2412352 100644
--- a/src/wallet/rpcdump.cpp
+++ b/src/wallet/rpcdump.cpp
@@ -148,7 +148,7 @@ UniValue importprivkey(const JSONRPCRequest& request)
         pwallet->UpdateTimeFirstKey(1);
 
         if (fRescan) {
-            pwallet->ScanForWalletTransactions(chainActive.Genesis(), true);
+            pwallet->RescanFromTime(TIMESTAMP_MIN, true /* update */);
         }
     }
 
@@ -278,7 +278,7 @@ UniValue importaddress(const JSONRPCRequest& request)
 
     if (fRescan)
     {
-        pwallet->ScanForWalletTransactions(chainActive.Genesis(), true);
+        pwallet->RescanFromTime(TIMESTAMP_MIN, true /* update */);
         pwallet->ReacceptWalletTransactions();
     }
 
@@ -436,7 +436,7 @@ UniValue importpubkey(const JSONRPCRequest& request)
 
     if (fRescan)
     {
-        pwallet->ScanForWalletTransactions(chainActive.Genesis(), true);
+        pwallet->RescanFromTime(TIMESTAMP_MIN, true /* update */);
         pwallet->ReacceptWalletTransactions();
     }
 
@@ -536,11 +536,7 @@ UniValue importwallet(const JSONRPCRequest& request)
     file.close();
     pwallet->ShowProgress("", 100); // hide progress dialog in GUI
     pwallet->UpdateTimeFirstKey(nTimeBegin);
-
-    CBlockIndex *pindex = chainActive.FindEarliestAtLeast(nTimeBegin - TIMESTAMP_WINDOW);
-
-    LogPrintf("Rescanning last %i blocks\n", pindex ? chainActive.Height() - pindex->nHeight + 1 : 0);
-    pwallet->ScanForWalletTransactions(pindex);
+    pwallet->RescanFromTime(nTimeBegin, false /* update */);
     pwallet->MarkDirty();
 
     if (!fGood)
@@ -1126,14 +1122,10 @@ UniValue importmulti(const JSONRPCRequest& mainRequest)
     }
 
     if (fRescan && fRunScan && requests.size()) {
-        CBlockIndex* pindex = nLowestTimestamp > minimumTimestamp ? chainActive.FindEarliestAtLeast(std::max<int64_t>(nLowestTimestamp - TIMESTAMP_WINDOW, 0)) : chainActive.Genesis();
-        CBlockIndex* scanFailed = nullptr;
-        if (pindex) {
-            scanFailed = pwallet->ScanForWalletTransactions(pindex, true);
-            pwallet->ReacceptWalletTransactions();
-        }
+        int64_t scannedTime = pwallet->RescanFromTime(nLowestTimestamp, true /* update */);
+        pwallet->ReacceptWalletTransactions();
 
-        if (scanFailed) {
+        if (scannedTime > nLowestTimestamp) {
             std::vector<UniValue> results = response.getValues();
             response.clear();
             response.setArray();
@@ -1143,7 +1135,7 @@ UniValue importmulti(const JSONRPCRequest& mainRequest)
                 // range, or if the import result already has an error set, let
                 // the result stand unmodified. Otherwise replace the result
                 // with an error message.
-                if (GetImportTimestamp(request, now) - TIMESTAMP_WINDOW > scanFailed->GetBlockTimeMax() || results.at(i).exists("error")) {
+                if (scannedTime <= GetImportTimestamp(request, now) || results.at(i).exists("error")) {
                     response.push_back(results.at(i));
                 } else {
                     UniValue result = UniValue(UniValue::VOBJ);
@@ -1159,7 +1151,7 @@ UniValue importmulti(const JSONRPCRequest& mainRequest)
                                       "caused by pruning or data corruption (see bitcoind log for details) and could "
                                       "be dealt with by downloading and rescanning the relevant blocks (see -reindex "
                                       "and -rescan options).",
-                                GetImportTimestamp(request, now), scanFailed->GetBlockTimeMax(), TIMESTAMP_WINDOW)));
+                                GetImportTimestamp(request, now), scannedTime - TIMESTAMP_WINDOW - 1, TIMESTAMP_WINDOW)));
                     response.push_back(std::move(result));
                 }
                 ++i;
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index f07a6cb5a5..0d1a86dd24 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -220,6 +220,10 @@ bool CWallet::LoadCryptedKey(const CPubKey &vchPubKey, const std::vector<unsigne
     return CCryptoKeyStore::AddCryptedKey(vchPubKey, vchCryptedSecret);
 }
 
+/**
+ * Update wallet first key creation time. This should be called whenever keys
+ * are added to the wallet, with the oldest key creation time.
+ */
 void CWallet::UpdateTimeFirstKey(int64_t nCreateTime)
 {
     AssertLockHeld(cs_wallet);
@@ -1468,6 +1472,34 @@ void CWalletTx::GetAmounts(std::list<COutputEntry>& listReceived,
 }
 
 /**
+ * Scan active chain for relevant transactions after importing keys. This should
+ * be called whenever new keys are added to the wallet, with the oldest key
+ * creation time.
+ *
+ * @return Earliest timestamp that could be successfully scanned from. Timestamp
+ * returned will be higher than startTime if relevant blocks could not be read.
+ */
+int64_t CWallet::RescanFromTime(int64_t startTime, bool update)
+{
+    AssertLockHeld(cs_main);
+    AssertLockHeld(cs_wallet);
+
+    // Find starting block. May be null if nCreateTime is greater than the
+    // highest blockchain timestamp, in which case there is nothing that needs
+    // to be scanned.
+    CBlockIndex* const startBlock = chainActive.FindEarliestAtLeast(startTime - TIMESTAMP_WINDOW);
+    LogPrintf("%s: Rescanning last %i blocks\n", __func__, startBlock ? chainActive.Height() - startBlock->nHeight + 1 : 0);
+
+    if (startBlock) {
+        const CBlockIndex* const failedBlock = ScanForWalletTransactions(startBlock, update);
+        if (failedBlock) {
+            return failedBlock->GetBlockTimeMax() + TIMESTAMP_WINDOW + 1;
+        }
+    }
+    return startTime;
+}
+
+/**
  * Scan the block chain (starting in pindexStart) for transactions
  * from or to us. If fUpdate is true, found transactions that already
  * exist in the wallet will be updated.
@@ -1488,11 +1520,6 @@ CBlockIndex* CWallet::ScanForWalletTransactions(CBlockIndex* pindexStart, bool f
         fAbortRescan = false;
         fScanningWallet = true;
 
-        // no need to read and scan block, if block was created before
-        // our wallet birthday (as adjusted for block time variability)
-        while (pindex && nTimeFirstKey && (pindex->GetBlockTime() < (nTimeFirstKey - TIMESTAMP_WINDOW)))
-            pindex = chainActive.Next(pindex);
-
         ShowProgress(_("Rescanning..."), 0); // show rescan progress in GUI as dialog or on splashscreen, if -rescan on startup
         double dProgressStart = GuessVerificationProgress(chainParams.TxData(), pindex);
         double dProgressTip = GuessVerificationProgress(chainParams.TxData(), chainActive.Tip());
@@ -3881,6 +3908,13 @@ CWallet* CWallet::CreateWalletFromFile(const std::string walletFile)
 
         uiInterface.InitMessage(_("Rescanning..."));
         LogPrintf("Rescanning last %i blocks (from block %i)...\n", chainActive.Height() - pindexRescan->nHeight, pindexRescan->nHeight);
+
+        // No need to read and scan block if block was created before
+        // our wallet birthday (as adjusted for block time variability)
+        while (pindexRescan && walletInstance->nTimeFirstKey && (pindexRescan->GetBlockTime() < (walletInstance->nTimeFirstKey - TIMESTAMP_WINDOW))) {
+            pindexRescan = chainActive.Next(pindexRescan);
+        }
+
         nStart = GetTimeMillis();
         walletInstance->ScanForWalletTransactions(pindexRescan, true);
         LogPrintf(" rescan      %15dms\n", GetTimeMillis() - nStart);
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index ad606b8535..6ed955cf58 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -68,6 +68,8 @@ static const bool DEFAULT_USE_HD_WALLET = true;
 
 extern const char * DEFAULT_WALLET_DAT;
 
+static const int64_t TIMESTAMP_MIN = 0;
+
 class CBlockIndex;
 class CCoinControl;
 class COutput;
@@ -919,6 +921,7 @@ public:
     void BlockConnected(const std::shared_ptr<const CBlock>& pblock, const CBlockIndex *pindex, const std::vector<CTransactionRef>& vtxConflicted) override;
     void BlockDisconnected(const std::shared_ptr<const CBlock>& pblock) override;
     bool AddToWalletIfInvolvingMe(const CTransactionRef& tx, const CBlockIndex* pIndex, int posInBlock, bool fUpdate);
+    int64_t RescanFromTime(int64_t startTime, bool update);
     CBlockIndex* ScanForWalletTransactions(CBlockIndex* pindexStart, bool fUpdate = false);
     void ReacceptWalletTransactions();
     void ResendWalletTransactions(int64_t nBestBlockTime, CConnman* connman) override;