Track keypool entries as internal vs external in memory

This resolves a super minor performance regressions in several
keypool-handling functions

src/wallet/wallet.cpp

@@ -2941,7 +2941,8 @@ DBErrors CWallet::LoadWallet(bool& fFirstRunRet)
         if (dbw->Rewrite("\x04pool"))
         {
             LOCK(cs_wallet);
-            setKeyPool.clear();
+            setInternalKeyPool.clear();
+            setExternalKeyPool.clear();
             // Note: can't top-up keypool here, because wallet is locked.
             // User will be prompted to unlock wallet the next operation
             // that requires a new key.
@@ -2969,7 +2970,8 @@ DBErrors CWallet::ZapSelectTx(std::vector<uint256>& vHashIn, std::vector<uint256
     {
         if (dbw->Rewrite("\x04pool"))
         {
-            setKeyPool.clear();
+            setInternalKeyPool.clear();
+            setExternalKeyPool.clear();
             // Note: can't top-up keypool here, because wallet is locked.
             // User will be prompted to unlock wallet the next operation
             // that requires a new key.
@@ -2994,7 +2996,8 @@ DBErrors CWallet::ZapWalletTx(std::vector<CWalletTx>& vWtx)
         if (dbw->Rewrite("\x04pool"))
         {
             LOCK(cs_wallet);
-            setKeyPool.clear();
+            setInternalKeyPool.clear();
+            setExternalKeyPool.clear();
             // Note: can't top-up keypool here, because wallet is locked.
             // User will be prompted to unlock wallet the next operation
             // that requires a new key.
@@ -3078,9 +3081,12 @@ bool CWallet::NewKeyPool()
     {
         LOCK(cs_wallet);
         CWalletDB walletdb(*dbw);
-        for (int64_t nIndex : setKeyPool)
+        for (int64_t nIndex : setInternalKeyPool)
             walletdb.ErasePool(nIndex);
-        setKeyPool.clear();
+        setInternalKeyPool.clear();
+        BOOST_FOREACH(int64_t nIndex, setExternalKeyPool)
+            walletdb.ErasePool(nIndex);
+        setExternalKeyPool.clear();
 
         if (!TopUpKeyPool()) {
             return false;
@@ -3092,25 +3098,8 @@ bool CWallet::NewKeyPool()
 
 size_t CWallet::KeypoolCountExternalKeys()
 {
-    AssertLockHeld(cs_wallet); // setKeyPool
-
-    // immediately return setKeyPool's size if HD or HD_SPLIT is disabled or not supported
-    if (!IsHDEnabled() || !CanSupportFeature(FEATURE_HD_SPLIT))
-        return setKeyPool.size();
-
-    CWalletDB walletdb(*dbw);
-
-    // count amount of external keys
-    size_t amountE = 0;
-    for(const int64_t& id : setKeyPool)
-    {
-        CKeyPool tmpKeypool;
-        if (!walletdb.ReadPool(id, tmpKeypool))
-            throw std::runtime_error(std::string(__func__) + ": read failed");
-        amountE += !tmpKeypool.fInternal;
-    }
-
-    return amountE;
+    AssertLockHeld(cs_wallet); // setExternalKeyPool
+    return setExternalKeyPool.size();
 }
 
 bool CWallet::TopUpKeyPool(unsigned int kpSize)
@@ -3130,10 +3119,8 @@ bool CWallet::TopUpKeyPool(unsigned int kpSize)
 
         // count amount of available keys (internal, external)
         // make sure the keypool of external and internal keys fits the user selected target (-keypool)
-        int64_t amountExternal = KeypoolCountExternalKeys();
-        int64_t amountInternal = setKeyPool.size() - amountExternal;
-        int64_t missingExternal = std::max(std::max((int64_t) nTargetSize, (int64_t) 1) - amountExternal, (int64_t) 0);
-        int64_t missingInternal = std::max(std::max((int64_t) nTargetSize, (int64_t) 1) - amountInternal, (int64_t) 0);
+        int64_t missingExternal = std::max(std::max((int64_t) nTargetSize, (int64_t) 1) - (int64_t)setExternalKeyPool.size(), (int64_t) 0);
+        int64_t missingInternal = std::max(std::max((int64_t) nTargetSize, (int64_t) 1) - (int64_t)setInternalKeyPool.size(), (int64_t) 0);
 
         if (!IsHDEnabled() || !CanSupportFeature(FEATURE_HD_SPLIT))
         {
@@ -3147,18 +3134,26 @@ bool CWallet::TopUpKeyPool(unsigned int kpSize)
             int64_t nEnd = 1;
             if (i < missingInternal)
                 internal = true;
-            if (!setKeyPool.empty())
-                nEnd = *(--setKeyPool.end()) + 1;
+            if (!setInternalKeyPool.empty())
+                nEnd = *(--setInternalKeyPool.end()) + 1;
+            if (!setExternalKeyPool.empty())
+                nEnd = std::max(nEnd, *(--setExternalKeyPool.end()) + 1);
+
             if (!walletdb.WritePool(nEnd, CKeyPool(GenerateNewKey(internal), internal)))
                 throw std::runtime_error(std::string(__func__) + ": writing generated key failed");
-            setKeyPool.insert(nEnd);
-            LogPrintf("keypool added key %d, size=%u, internal=%d\n", nEnd, setKeyPool.size(), internal);
+
+            if (internal) {
+                setInternalKeyPool.insert(nEnd);
+            } else {
+                setExternalKeyPool.insert(nEnd);
+            }
+            LogPrintf("keypool added key %d, size=%u (%u internal), new key is %s\n", nEnd, setInternalKeyPool.size() + setExternalKeyPool.size(), setInternalKeyPool.size(), internal ? "internal" : "external");
         }
     }
     return true;
 }
 
-void CWallet::ReserveKeyFromKeyPool(int64_t& nIndex, CKeyPool& keypool, bool internal)
+void CWallet::ReserveKeyFromKeyPool(int64_t& nIndex, CKeyPool& keypool, bool fRequestedInternal)
 {
     nIndex = -1;
     keypool.vchPubKey = CPubKey();
@@ -3168,30 +3163,30 @@ void CWallet::ReserveKeyFromKeyPool(int64_t& nIndex, CKeyPool& keypool, bool int
         if (!IsLocked())
             TopUpKeyPool();
 
+        bool fReturningInternal = IsHDEnabled() && CanSupportFeature(FEATURE_HD_SPLIT) && fRequestedInternal;
+        std::set<int64_t>& setKeyPool = fReturningInternal ? setInternalKeyPool : setExternalKeyPool;
+
         // Get the oldest key
         if(setKeyPool.empty())
             return;
 
         CWalletDB walletdb(*dbw);
 
-        // try to find a key that matches the internal/external filter
-        for(const int64_t& id : setKeyPool)
-        {
-            CKeyPool tmpKeypool;
-            if (!walletdb.ReadPool(id, tmpKeypool))
+        auto it = setKeyPool.begin();
+        nIndex = *it;
+        setKeyPool.erase(it);
+        if (!walletdb.ReadPool(nIndex, keypool)) {
             throw std::runtime_error(std::string(__func__) + ": read failed");
-            if (!HaveKey(tmpKeypool.vchPubKey.GetID()))
+        }
+        if (!HaveKey(keypool.vchPubKey.GetID())) {
             throw std::runtime_error(std::string(__func__) + ": unknown key in key pool");
-            if (!IsHDEnabled() || !CanSupportFeature(FEATURE_HD_SPLIT) || tmpKeypool.fInternal == internal)
-            {
-                nIndex = id;
-                keypool = tmpKeypool;
-                setKeyPool.erase(id);
-                assert(keypool.vchPubKey.IsValid());
-                LogPrintf("keypool reserve %d\n", nIndex);
-                return;
         }
+        if (keypool.fInternal != fReturningInternal) {
+            throw std::runtime_error(std::string(__func__) + ": keypool entry misclassified");
         }
+
+        assert(keypool.vchPubKey.IsValid());
+        LogPrintf("keypool reserve %d\n", nIndex);
     }
 }
 
@@ -3203,12 +3198,16 @@ void CWallet::KeepKey(int64_t nIndex)
     LogPrintf("keypool keep %d\n", nIndex);
 }
 
-void CWallet::ReturnKey(int64_t nIndex)
+void CWallet::ReturnKey(int64_t nIndex, bool fInternal)
 {
     // Return to key pool
     {
         LOCK(cs_wallet);
-        setKeyPool.insert(nIndex);
+        if (fInternal) {
+            setInternalKeyPool.insert(nIndex);
+        } else {
+            setExternalKeyPool.insert(nIndex);
+        }
     }
     LogPrintf("keypool return %d\n", nIndex);
 }
@@ -3232,41 +3231,12 @@ bool CWallet::GetKeyFromPool(CPubKey& result, bool internal)
     return true;
 }
 
-int64_t CWallet::GetOldestKeyPoolTime()
-{
-    LOCK(cs_wallet);
-
-    // if the keypool is empty, return <NOW>
-    if (setKeyPool.empty())
+static int64_t GetOldestKeyTimeInPool(const std::set<int64_t>& setKeyPool, CWalletDB& walletdb) {
+    if (setKeyPool.empty()) {
         return GetTime();
+    }
 
     CKeyPool keypool;
-    CWalletDB walletdb(*dbw);
-
-    if (IsHDEnabled() && CanSupportFeature(FEATURE_HD_SPLIT))
-    {
-        // if HD & HD Chain Split is enabled, response max(oldest-internal-key, oldest-external-key)
-        int64_t now = GetTime();
-        int64_t oldest_external = now, oldest_internal = now;
-
-        for(const int64_t& id : setKeyPool)
-        {
-            if (!walletdb.ReadPool(id, keypool)) {
-                throw std::runtime_error(std::string(__func__) + ": read failed");
-            }
-            if (keypool.fInternal && keypool.nTime < oldest_internal) {
-                oldest_internal = keypool.nTime;
-            }
-            else if (!keypool.fInternal && keypool.nTime < oldest_external) {
-                oldest_external = keypool.nTime;
-            }
-            if (oldest_internal != now && oldest_external != now) {
-                break;
-            }
-        }
-        return std::max(oldest_internal, oldest_external);
-    }
-    // load oldest key from keypool, get time and return
     int64_t nIndex = *(setKeyPool.begin());
     if (!walletdb.ReadPool(nIndex, keypool))
         throw std::runtime_error(std::string(__func__) + ": read oldest key in keypool failed");
@@ -3274,6 +3244,21 @@ int64_t CWallet::GetOldestKeyPoolTime()
     return keypool.nTime;
 }
 
+int64_t CWallet::GetOldestKeyPoolTime()
+{
+    LOCK(cs_wallet);
+
+    CWalletDB walletdb(*dbw);
+
+    // load oldest key from keypool, get time and return
+    int64_t oldestKey = GetOldestKeyTimeInPool(setExternalKeyPool, walletdb);
+    if (IsHDEnabled() && CanSupportFeature(FEATURE_HD_SPLIT)) {
+        oldestKey = std::max(GetOldestKeyTimeInPool(setInternalKeyPool, walletdb), oldestKey);
+    }
+
+    return oldestKey;
+}
+
 std::map<CTxDestination, CAmount> CWallet::GetAddressBalances()
 {
     std::map<CTxDestination, CAmount> balances;
@@ -3432,6 +3417,7 @@ bool CReserveKey::GetReservedKey(CPubKey& pubkey, bool internal)
         else {
             return false;
         }
+        fInternal = keypool.fInternal;
     }
     assert(vchPubKey.IsValid());
     pubkey = vchPubKey;
@@ -3449,18 +3435,12 @@ void CReserveKey::KeepKey()
 void CReserveKey::ReturnKey()
 {
     if (nIndex != -1)
-        pwallet->ReturnKey(nIndex);
+        pwallet->ReturnKey(nIndex, fInternal);
     nIndex = -1;
     vchPubKey = CPubKey();
 }
 
-void CWallet::GetAllReserveKeys(std::set<CKeyID>& setAddress) const
-{
-    setAddress.clear();
-
-    CWalletDB walletdb(*dbw);
-
-    LOCK2(cs_main, cs_wallet);
+static void LoadReserveKeysToSet(std::set<CKeyID>& setAddress, const std::set<int64_t>& setKeyPool, CWalletDB& walletdb) {
     for (const int64_t& id : setKeyPool)
     {
         CKeyPool keypool;
@@ -3468,12 +3448,27 @@ void CWallet::GetAllReserveKeys(std::set<CKeyID>& setAddress) const
             throw std::runtime_error(std::string(__func__) + ": read failed");
         assert(keypool.vchPubKey.IsValid());
         CKeyID keyID = keypool.vchPubKey.GetID();
-        if (!HaveKey(keyID))
-            throw std::runtime_error(std::string(__func__) + ": unknown key in key pool");
         setAddress.insert(keyID);
     }
 }
 
+void CWallet::GetAllReserveKeys(std::set<CKeyID>& setAddress) const
+{
+    setAddress.clear();
+
+    CWalletDB walletdb(*dbw);
+
+    LOCK2(cs_main, cs_wallet);
+    LoadReserveKeysToSet(setAddress, setInternalKeyPool, walletdb);
+    LoadReserveKeysToSet(setAddress, setExternalKeyPool, walletdb);
+
+    for (const CKeyID& keyID : setAddress) {
+        if (!HaveKey(keyID)) {
+            throw std::runtime_error(std::string(__func__) + ": unknown key in key pool");
+        }
+    }
+}
+
 void CWallet::GetScriptForMining(std::shared_ptr<CReserveScript> &script)
 {
     std::shared_ptr<CReserveKey> rKey = std::make_shared<CReserveKey>(this);

src/wallet/wallet.h

@@ -696,7 +696,8 @@ private:
     /* HD derive new child key (on internal or external chain) */
     void DeriveNewChildKey(CKeyMetadata& metadata, CKey& secret, bool internal = false);
 
-    std::set<int64_t> setKeyPool;
+    std::set<int64_t> setInternalKeyPool;
+    std::set<int64_t> setExternalKeyPool;
 
     int64_t nTimeFirstKey;
 
@@ -741,7 +742,11 @@ public:
 
     void LoadKeyPool(int nIndex, const CKeyPool &keypool)
     {
-        setKeyPool.insert(nIndex);
+        if (keypool.fInternal) {
+            setInternalKeyPool.insert(nIndex);
+        } else {
+            setExternalKeyPool.insert(nIndex);
+        }
 
         // If no metadata exists yet, create a default with the pool key's
         // creation time. Note that this may be overwritten by actually
@@ -970,9 +975,9 @@ public:
     bool NewKeyPool();
     size_t KeypoolCountExternalKeys();
     bool TopUpKeyPool(unsigned int kpSize = 0);
-    void ReserveKeyFromKeyPool(int64_t& nIndex, CKeyPool& keypool, bool internal);
+    void ReserveKeyFromKeyPool(int64_t& nIndex, CKeyPool& keypool, bool fRequestedInternal);
     void KeepKey(int64_t nIndex);
-    void ReturnKey(int64_t nIndex);
+    void ReturnKey(int64_t nIndex, bool fInternal);
     bool GetKeyFromPool(CPubKey &key, bool internal = false);
     int64_t GetOldestKeyPoolTime();
     void GetAllReserveKeys(std::set<CKeyID>& setAddress) const;
@@ -1026,8 +1031,8 @@ public:
     
     unsigned int GetKeyPoolSize()
     {
-        AssertLockHeld(cs_wallet); // setKeyPool
-        return setKeyPool.size();
+        AssertLockHeld(cs_wallet); // set{Ex,In}ternalKeyPool
+        return setInternalKeyPool.size() + setExternalKeyPool.size();
     }
 
     bool SetDefaultKey(const CPubKey &vchPubKey);
@@ -1131,11 +1136,13 @@ protected:
     CWallet* pwallet;
     int64_t nIndex;
     CPubKey vchPubKey;
+    bool fInternal;
 public:
     CReserveKey(CWallet* pwalletIn)
     {
         nIndex = -1;
         pwallet = pwalletIn;
+        fInternal = false;
     }
 
     CReserveKey() = default;