Use importmulti timestamp when importing watch only keys

When importing a watch-only address over importmulti with a specific timestamp,
the wallet's nTimeFirstKey is currently set to 1. After this change, the
provided timestamp will be used and stored as metadata associated with
watch-only key. This can improve wallet performance because it can avoid the
need to scan the entire blockchain for watch only addresses when timestamps are
provided.

Also adds timestamp to validateaddress return value (needed for tests).

Fixes #9034.

6 files changed, 75 insertions, 34 deletions

diff --git a/src/rpc/misc.cpp b/src/rpc/misc.cpp
index 25fad3c2e3..6fd50127bd 100644
--- a/src/rpc/misc.cpp
+++ b/src/rpc/misc.cpp
@@ -208,6 +208,9 @@ UniValue validateaddress(const JSONRPCRequest& request)
         if (pwalletMain) {
             const auto& meta = pwalletMain->mapKeyMetadata;
             auto it = address.GetKeyID(keyID) ? meta.find(keyID) : meta.end();
+            if (it == meta.end()) {
+                it = meta.find(CScriptID(scriptPubKey));
+            }
             if (it != meta.end()) {
                 ret.push_back(Pair("timestamp", it->second.nCreateTime));
                 if (!it->second.hdKeypath.empty()) {
diff --git a/src/wallet/rpcdump.cpp b/src/wallet/rpcdump.cpp
index f358d720cd..0a3225937e 100644
--- a/src/wallet/rpcdump.cpp
+++ b/src/wallet/rpcdump.cpp
@@ -161,7 +161,7 @@ void ImportScript(const CScript& script, const string& strLabel, bool isRedeemSc
 
     pwalletMain->MarkDirty();
 
-    if (!pwalletMain->HaveWatchOnly(script) && !pwalletMain->AddWatchOnly(script))
+    if (!pwalletMain->HaveWatchOnly(script) && !pwalletMain->AddWatchOnly(script, 0 /* nCreateTime */))
         throw JSONRPCError(RPC_WALLET_ERROR, "Error adding address to wallet");
 
     if (isRedeemScript) {
@@ -575,15 +575,17 @@ UniValue dumpwallet(const JSONRPCRequest& request)
     if (!file.is_open())
         throw JSONRPCError(RPC_INVALID_PARAMETER, "Cannot open wallet dump file");
 
-    std::map<CKeyID, int64_t> mapKeyBirth;
+    std::map<CTxDestination, int64_t> mapKeyBirth;
     std::set<CKeyID> setKeyPool;
     pwalletMain->GetKeyBirthTimes(mapKeyBirth);
     pwalletMain->GetAllReserveKeys(setKeyPool);
 
     // sort time/key pairs
     std::vector<std::pair<int64_t, CKeyID> > vKeyBirth;
-    for (std::map<CKeyID, int64_t>::const_iterator it = mapKeyBirth.begin(); it != mapKeyBirth.end(); it++) {
-        vKeyBirth.push_back(std::make_pair(it->second, it->first));
+    for (const auto& entry : mapKeyBirth) {
+        if (const CKeyID* keyID = boost::get<CKeyID>(&entry.first)) { // set and test
+            vKeyBirth.push_back(std::make_pair(entry.second, *keyID));
+        }
     }
     mapKeyBirth.clear();
     std::sort(vKeyBirth.begin(), vKeyBirth.end());
@@ -720,7 +722,7 @@ UniValue ProcessImport(const UniValue& data, const int64_t timestamp)
 
             pwalletMain->MarkDirty();
 
-            if (!pwalletMain->HaveWatchOnly(redeemScript) && !pwalletMain->AddWatchOnly(redeemScript)) {
+            if (!pwalletMain->HaveWatchOnly(redeemScript) && !pwalletMain->AddWatchOnly(redeemScript, timestamp)) {
                 throw JSONRPCError(RPC_WALLET_ERROR, "Error adding address to wallet");
             }
 
@@ -737,7 +739,7 @@ UniValue ProcessImport(const UniValue& data, const int64_t timestamp)
 
             pwalletMain->MarkDirty();
 
-            if (!pwalletMain->HaveWatchOnly(redeemDestination) && !pwalletMain->AddWatchOnly(redeemDestination)) {
+            if (!pwalletMain->HaveWatchOnly(redeemDestination) && !pwalletMain->AddWatchOnly(redeemDestination, timestamp)) {
                 throw JSONRPCError(RPC_WALLET_ERROR, "Error adding address to wallet");
             }
 
@@ -830,7 +832,7 @@ UniValue ProcessImport(const UniValue& data, const int64_t timestamp)
 
                 pwalletMain->MarkDirty();
 
-                if (!pwalletMain->HaveWatchOnly(pubKeyScript) && !pwalletMain->AddWatchOnly(pubKeyScript)) {
+                if (!pwalletMain->HaveWatchOnly(pubKeyScript) && !pwalletMain->AddWatchOnly(pubKeyScript, timestamp)) {
                     throw JSONRPCError(RPC_WALLET_ERROR, "Error adding address to wallet");
                 }
 
@@ -848,7 +850,7 @@ UniValue ProcessImport(const UniValue& data, const int64_t timestamp)
 
                 pwalletMain->MarkDirty();
 
-                if (!pwalletMain->HaveWatchOnly(scriptRawPubKey) && !pwalletMain->AddWatchOnly(scriptRawPubKey)) {
+                if (!pwalletMain->HaveWatchOnly(scriptRawPubKey) && !pwalletMain->AddWatchOnly(scriptRawPubKey, timestamp)) {
                     throw JSONRPCError(RPC_WALLET_ERROR, "Error adding address to wallet");
                 }
 
@@ -922,7 +924,7 @@ UniValue ProcessImport(const UniValue& data, const int64_t timestamp)
 
                 pwalletMain->MarkDirty();
 
-                if (!pwalletMain->HaveWatchOnly(script) && !pwalletMain->AddWatchOnly(script)) {
+                if (!pwalletMain->HaveWatchOnly(script) && !pwalletMain->AddWatchOnly(script, timestamp)) {
                     throw JSONRPCError(RPC_WALLET_ERROR, "Error adding address to wallet");
                 }
 
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 192af22cb8..f8f5a9306d 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -206,11 +206,11 @@ bool CWallet::AddCryptedKey(const CPubKey &vchPubKey,
     return false;
 }
 
-bool CWallet::LoadKeyMetadata(const CPubKey &pubkey, const CKeyMetadata &meta)
+bool CWallet::LoadKeyMetadata(const CTxDestination& keyID, const CKeyMetadata &meta)
 {
     AssertLockHeld(cs_wallet); // mapKeyMetadata
     UpdateTimeFirstKey(meta.nCreateTime);
-    mapKeyMetadata[pubkey.GetID()] = meta;
+    mapKeyMetadata[keyID] = meta;
     return true;
 }
 
@@ -256,15 +256,22 @@ bool CWallet::LoadCScript(const CScript& redeemScript)
     return CCryptoKeyStore::AddCScript(redeemScript);
 }
 
-bool CWallet::AddWatchOnly(const CScript &dest)
+bool CWallet::AddWatchOnly(const CScript& dest)
 {
     if (!CCryptoKeyStore::AddWatchOnly(dest))
         return false;
-    nTimeFirstKey = 1; // No birthday information for watch-only keys.
+    const CKeyMetadata& meta = mapKeyMetadata[CScriptID(dest)];
+    UpdateTimeFirstKey(meta.nCreateTime);
     NotifyWatchonlyChanged(true);
     if (!fFileBacked)
         return true;
-    return CWalletDB(strWalletFile).WriteWatchOnly(dest);
+    return CWalletDB(strWalletFile).WriteWatchOnly(dest, meta);
+}
+
+bool CWallet::AddWatchOnly(const CScript& dest, int64_t nCreateTime)
+{
+    mapKeyMetadata[CScriptID(dest)].nCreateTime = nCreateTime;
+    return AddWatchOnly(dest);
 }
 
 bool CWallet::RemoveWatchOnly(const CScript &dest)
@@ -3425,14 +3432,16 @@ public:
     void operator()(const CNoDestination &none) {}
 };
 
-void CWallet::GetKeyBirthTimes(std::map<CKeyID, int64_t> &mapKeyBirth) const {
+void CWallet::GetKeyBirthTimes(std::map<CTxDestination, int64_t> &mapKeyBirth) const {
     AssertLockHeld(cs_wallet); // mapKeyMetadata
     mapKeyBirth.clear();
 
     // get birth times for keys with metadata
-    for (std::map<CKeyID, CKeyMetadata>::const_iterator it = mapKeyMetadata.begin(); it != mapKeyMetadata.end(); it++)
-        if (it->second.nCreateTime)
-            mapKeyBirth[it->first] = it->second.nCreateTime;
+    for (const auto& entry : mapKeyMetadata) {
+        if (entry.second.nCreateTime) {
+            mapKeyBirth[entry.first] = entry.second.nCreateTime;
+        }
+    }
 
     // map in which we'll infer heights of other keys
     CBlockIndex *pindexMax = chainActive[std::max(0, chainActive.Height() - 144)]; // the tip can be reorganized; use a 144-block safety margin
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 8d3ee9dddc..990c3bdf41 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -614,6 +614,17 @@ private:
 
     int64_t nTimeFirstKey;
 
+    /**
+     * Private version of AddWatchOnly method which does not accept a
+     * timestamp, and which will reset the wallet's nTimeFirstKey value to 1 if
+     * the watch key did not previously have a timestamp associated with it.
+     * Because this is an inherited virtual method, it is accessible despite
+     * being marked private, but it is marked private anyway to encourage use
+     * of the other AddWatchOnly which accepts a timestamp and sets
+     * nTimeFirstKey more intelligently for more efficient rescans.
+     */
+    bool AddWatchOnly(const CScript& dest) override;
+
 public:
     /*
      * Main wallet lock.
@@ -638,7 +649,9 @@ public:
             mapKeyMetadata[keyid] = CKeyMetadata(keypool.nTime);
     }
 
-    std::map<CKeyID, CKeyMetadata> mapKeyMetadata;
+    // Map from Key ID (for regular keys) or Script ID (for watch-only keys) to
+    // key metadata.
+    std::map<CTxDestination, CKeyMetadata> mapKeyMetadata;
 
     typedef std::map<unsigned int, CMasterKey> MasterKeyMap;
     MasterKeyMap mapMasterKeys;
@@ -728,7 +741,7 @@ public:
     //! Adds a key to the store, without saving it to disk (used by LoadWallet)
     bool LoadKey(const CKey& key, const CPubKey &pubkey) { return CCryptoKeyStore::AddKeyPubKey(key, pubkey); }
     //! Load metadata (used by LoadWallet)
-    bool LoadKeyMetadata(const CPubKey &pubkey, const CKeyMetadata &metadata);
+    bool LoadKeyMetadata(const CTxDestination& pubKey, const CKeyMetadata &metadata);
 
     bool LoadMinVersion(int nVersion) { AssertLockHeld(cs_wallet); nWalletVersion = nVersion; nWalletMaxVersion = std::max(nWalletMaxVersion, nVersion); return true; }
     void UpdateTimeFirstKey(int64_t nCreateTime);
@@ -750,7 +763,7 @@ public:
     bool GetDestData(const CTxDestination &dest, const std::string &key, std::string *value) const;
 
     //! Adds a watch-only address to the store, and saves it to disk.
-    bool AddWatchOnly(const CScript &dest);
+    bool AddWatchOnly(const CScript& dest, int64_t nCreateTime);
     bool RemoveWatchOnly(const CScript &dest);
     //! Adds a watch-only address to the store, without saving it to disk (used by LoadWallet)
     bool LoadWatchOnly(const CScript &dest);
@@ -759,7 +772,7 @@ public:
     bool ChangeWalletPassphrase(const SecureString& strOldWalletPassphrase, const SecureString& strNewWalletPassphrase);
     bool EncryptWallet(const SecureString& strWalletPassphrase);
 
-    void GetKeyBirthTimes(std::map<CKeyID, int64_t> &mapKeyBirth) const;
+    void GetKeyBirthTimes(std::map<CTxDestination, int64_t> &mapKeyBirth) const;
 
     /** 
      * Increment the next transaction order id
diff --git a/src/wallet/walletdb.cpp b/src/wallet/walletdb.cpp
index 15e1e4c45f..106a59d562 100644
--- a/src/wallet/walletdb.cpp
+++ b/src/wallet/walletdb.cpp
@@ -120,15 +120,19 @@ bool CWalletDB::WriteCScript(const uint160& hash, const CScript& redeemScript)
     return Write(std::make_pair(std::string("cscript"), hash), *(const CScriptBase*)(&redeemScript), false);
 }
 
-bool CWalletDB::WriteWatchOnly(const CScript &dest)
+bool CWalletDB::WriteWatchOnly(const CScript &dest, const CKeyMetadata& keyMeta)
 {
     nWalletDBUpdateCounter++;
+    if (!Write(std::make_pair(std::string("watchmeta"), *(const CScriptBase*)(&dest)), keyMeta))
+        return false;
     return Write(std::make_pair(std::string("watchs"), *(const CScriptBase*)(&dest)), '1');
 }
 
 bool CWalletDB::EraseWatchOnly(const CScript &dest)
 {
     nWalletDBUpdateCounter++;
+    if (!Erase(std::make_pair(std::string("watchmeta"), *(const CScriptBase*)(&dest))))
+        return false;
     return Erase(std::make_pair(std::string("watchs"), *(const CScriptBase*)(&dest)));
 }
 
@@ -259,6 +263,7 @@ class CWalletScanState {
 public:
     unsigned int nKeys;
     unsigned int nCKeys;
+    unsigned int nWatchKeys;
     unsigned int nKeyMeta;
     bool fIsEncrypted;
     bool fAnyUnordered;
@@ -266,7 +271,7 @@ public:
     vector<uint256> vWalletUpgrade;
 
     CWalletScanState() {
-        nKeys = nCKeys = nKeyMeta = 0;
+        nKeys = nCKeys = nWatchKeys = nKeyMeta = 0;
         fIsEncrypted = false;
         fAnyUnordered = false;
         nFileVersion = 0;
@@ -348,16 +353,13 @@ ReadKeyValue(CWallet* pwallet, CDataStream& ssKey, CDataStream& ssValue,
         }
         else if (strType == "watchs")
         {
+            wss.nWatchKeys++;
             CScript script;
             ssKey >> *(CScriptBase*)(&script);
             char fYes;
             ssValue >> fYes;
             if (fYes == '1')
                 pwallet->LoadWatchOnly(script);
-
-            // Watch-only addresses have no birthday information for now,
-            // so set the wallet birthday to the beginning of time.
-            pwallet->UpdateTimeFirstKey(1);
         }
         else if (strType == "key" || strType == "wkey")
         {
@@ -458,15 +460,27 @@ ReadKeyValue(CWallet* pwallet, CDataStream& ssKey, CDataStream& ssValue,
             }
             wss.fIsEncrypted = true;
         }
-        else if (strType == "keymeta")
+        else if (strType == "keymeta" || strType == "watchmeta")
         {
-            CPubKey vchPubKey;
-            ssKey >> vchPubKey;
+            CTxDestination keyID;
+            if (strType == "keymeta")
+            {
+              CPubKey vchPubKey;
+              ssKey >> vchPubKey;
+              keyID = vchPubKey.GetID();
+            }
+            else if (strType == "watchmeta")
+            {
+              CScript script;
+              ssKey >> *(CScriptBase*)(&script);
+              keyID = CScriptID(script);
+            }
+
             CKeyMetadata keyMeta;
             ssValue >> keyMeta;
             wss.nKeyMeta++;
 
-            pwallet->LoadKeyMetadata(vchPubKey, keyMeta);
+            pwallet->LoadKeyMetadata(keyID, keyMeta);
         }
         else if (strType == "defaultkey")
         {
@@ -620,7 +634,7 @@ DBErrors CWalletDB::LoadWallet(CWallet* pwallet)
            wss.nKeys, wss.nCKeys, wss.nKeyMeta, wss.nKeys + wss.nCKeys);
 
     // nTimeFirstKey is only reliable if all keys have metadata
-    if ((wss.nKeys + wss.nCKeys) != wss.nKeyMeta)
+    if ((wss.nKeys + wss.nCKeys + wss.nWatchKeys) != wss.nKeyMeta)
         pwallet->UpdateTimeFirstKey(1);
 
     BOOST_FOREACH(uint256 hash, wss.vWalletUpgrade)
diff --git a/src/wallet/walletdb.h b/src/wallet/walletdb.h
index 8437a95ba7..c7c65465df 100644
--- a/src/wallet/walletdb.h
+++ b/src/wallet/walletdb.h
@@ -135,7 +135,7 @@ public:
 
     bool WriteCScript(const uint160& hash, const CScript& redeemScript);
 
-    bool WriteWatchOnly(const CScript &script);
+    bool WriteWatchOnly(const CScript &script, const CKeyMetadata &keymeta);
     bool EraseWatchOnly(const CScript &script);
 
     bool WriteBestBlock(const CBlockLocator& locator);