From 0b91aeefa7af0e91d97f9e84d515384743ef1167 Mon Sep 17 00:00:00 2001
From: Kalle Alm <kalle.alm@gmail.com>
Date: Mon, 17 Apr 2017 23:32:01 +0900
Subject: [PATCH] [wallet] Add support for aborting wallet transaction rescans.

---
 src/wallet/wallet.cpp |  9 ++++++++-
 src/wallet/wallet.h   | 17 +++++++++++++++--
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 1e266924f..d2d7200d2 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -1758,6 +1758,8 @@ int CWallet::ScanForWalletTransactions(CBlockIndex* pindexStart, bool fUpdate)
     CBlockIndex* pindex = pindexStart;
     {
         LOCK2(cs_main, cs_wallet);
+        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)
@@ -1767,7 +1769,7 @@ int CWallet::ScanForWalletTransactions(CBlockIndex* pindexStart, bool fUpdate)
         ShowProgress(_("Rescanning..."), 0); // show rescan progress in GUI as dialog or on splashscreen, if -rescan on startup
         double dProgressStart = Checkpoints::GuessVerificationProgress(chainParams.Checkpoints(), pindex, false);
         double dProgressTip = Checkpoints::GuessVerificationProgress(chainParams.Checkpoints(), chainActive.Tip(), false);
-        while (pindex)
+        while (pindex && !fAbortRescan)
         {
             if (pindex->nHeight % 100 == 0 && dProgressTip - dProgressStart > 0.0)
                 ShowProgress(_("Rescanning..."), std::max(1, std::min(99, (int)((Checkpoints::GuessVerificationProgress(chainParams.Checkpoints(), pindex, false) - dProgressStart) / (dProgressTip - dProgressStart) * 100))));
@@ -1785,7 +1787,12 @@ int CWallet::ScanForWalletTransactions(CBlockIndex* pindexStart, bool fUpdate)
                 LogPrintf("Still rescanning. At block %d. Progress=%f\n", pindex->nHeight, Checkpoints::GuessVerificationProgress(chainParams.Checkpoints(), pindex));
             }
         }
+        if (pindex && fAbortRescan) {
+            LogPrintf("Rescan aborted at block %d. Progress=%f\n", pindex->nHeight, Checkpoints::GuessVerificationProgress(chainParams.Checkpoints(), pindex));
+        }
         ShowProgress(_("Rescanning..."), 100); // hide progress dialog in GUI
+
+        fScanningWallet = false;
     }
     return ret;
 }
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 52809e7d9..514bd52a6 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -79,8 +79,8 @@ enum WalletFeature
     FEATURE_WALLETCRYPT = 40000, // wallet encryption
     FEATURE_COMPRPUBKEY = 60000, // compressed public keys
 
-	FEATURE_HD = 330000, // Hierarchical key derivation after BIP32 (HD Wallet)
-	FEATURE_LATEST = FEATURE_COMPRPUBKEY // HD is optional, use FEATURE_COMPRPUBKEY as latest version
+    FEATURE_HD = 330000, // Hierarchical key derivation after BIP32 (HD Wallet)
+    FEATURE_LATEST = FEATURE_COMPRPUBKEY // HD is optional, use FEATURE_COMPRPUBKEY as latest version
 };
 
 /** A key pool entry */
@@ -550,6 +550,9 @@ private:
 class CWallet : public CCryptoKeyStore, public CValidationInterface
 {
 private:
+    std::atomic<bool> fAbortRescan;
+    std::atomic<bool> fScanningWallet;
+
     /**
      * Select a set of coins such that nValueRet >= nTargetValue and at least
      * all coins from coinControl are selected; Never select unconfirmed coins
@@ -645,6 +648,9 @@ public:
         nTimeFirstKey = 0;
         fBroadcastTransactions = false;
         nConflictsReceived = 0;
+
+        fAbortRescan = false;
+        fScanningWallet = false;
     }
 
     std::map<uint256, CWalletTx> mapWallet;
@@ -691,6 +697,13 @@ public:
     void UnlockAllCoins();
     void ListLockedCoins(std::vector<COutPoint>& vOutpts);
 
+    /*
+     * Rescan abort properties
+     */
+    void AbortRescan() { fAbortRescan = true; }
+    bool IsAbortingRescan() { return fAbortRescan; }
+    bool IsScanning() { return fScanningWallet; }
+
     /**
      * keystore implementation
      * Generate a new key