1 files changed, 125 insertions, 74 deletions
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 62ba0aa962..5e3bbe2f37 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -1,5 +1,5 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
-// Copyright (c) 2009-2018 The Bitcoin Core developers
+// Copyright (c) 2009-2019 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
@@ -73,6 +73,12 @@ static const unsigned int DEFAULT_TX_CONFIRM_TARGET = 6;
 static const bool DEFAULT_WALLET_RBF = false;
 static const bool DEFAULT_WALLETBROADCAST = true;
 static const bool DEFAULT_DISABLE_WALLET = false;
+//! -maxtxfee default
+constexpr CAmount DEFAULT_TRANSACTION_MAXFEE{COIN / 10};
+//! Discourage users to set fees higher than this amount (in satoshis) per kB
+constexpr CAmount HIGH_TX_FEE_PER_KB{COIN / 100};
+//! -maxtxfee will warn if called with a higher fee than this amount (in satoshis)
+constexpr CAmount HIGH_MAX_TX_FEE{100 * HIGH_TX_FEE_PER_KB};
 
 //! Pre-calculated constants for input size estimation in *virtual size*
 static constexpr size_t DUMMY_NESTED_P2WPKH_INPUT_SIZE = 91;
@@ -135,14 +141,61 @@ enum WalletFlags : uint64_t {
 
 static constexpr uint64_t g_known_wallet_flags = WALLET_FLAG_DISABLE_PRIVATE_KEYS | WALLET_FLAG_BLANK_WALLET | WALLET_FLAG_KEY_ORIGIN_METADATA;
 
-/** A key pool entry */
+/** A key from a CWallet's keypool
+ *
+ * The wallet holds one (for pre HD-split wallets) or several keypools. These
+ * are sets of keys that have not yet been used to provide addresses or receive
+ * change.
+ *
+ * The Bitcoin Core wallet was originally a collection of unrelated private
+ * keys with their associated addresses. If a non-HD wallet generated a
+ * key/address, gave that address out and then restored a backup from before
+ * that key's generation, then any funds sent to that address would be
+ * lost definitively.
+ *
+ * The keypool was implemented to avoid this scenario (commit: 10384941). The
+ * wallet would generate a set of keys (100 by default). When a new public key
+ * was required, either to give out as an address or to use in a change output,
+ * it would be drawn from the keypool. The keypool would then be topped up to
+ * maintain 100 keys. This ensured that as long as the wallet hadn't used more
+ * than 100 keys since the previous backup, all funds would be safe, since a
+ * restored wallet would be able to scan for all owned addresses.
+ *
+ * A keypool also allowed encrypted wallets to give out addresses without
+ * having to be decrypted to generate a new private key.
+ *
+ * With the introduction of HD wallets (commit: f1902510), the keypool
+ * essentially became an address look-ahead pool. Restoring old backups can no
+ * longer definitively lose funds as long as the addresses used were from the
+ * wallet's HD seed (since all private keys can be rederived from the seed).
+ * However, if many addresses were used since the backup, then the wallet may
+ * not know how far ahead in the HD chain to look for its addresses. The
+ * keypool is used to implement a 'gap limit'. The keypool maintains a set of
+ * keys (by default 1000) ahead of the last used key and scans for the
+ * addresses of those keys.  This avoids the risk of not seeing transactions
+ * involving the wallet's addresses, or of re-using the same address.
+ *
+ * The HD-split wallet feature added a second keypool (commit: 02592f4c). There
+ * is an external keypool (for addresses to hand out) and an internal keypool
+ * (for change addresses).
+ *
+ * Keypool keys are stored in the wallet/keystore's keymap. The keypool data is
+ * stored as sets of indexes in the wallet (setInternalKeyPool,
+ * setExternalKeyPool and set_pre_split_keypool), and a map from the key to the
+ * index (m_pool_key_to_index). The CKeyPool object is used to
+ * serialize/deserialize the pool data to/from the database.
+ */
 class CKeyPool
 {
 public:
+    //! The time at which the key was generated. Set in AddKeypoolPubKeyWithDB
     int64_t nTime;
+    //! The public key
     CPubKey vchPubKey;
-    bool fInternal; // for change outputs
-    bool m_pre_split; // For keys generated before keypool split upgrade
+    //! Whether this keypool entry is in the internal keypool (for change outputs)
+    bool fInternal;
+    //! Whether this key was generated for a keypool before the wallet was upgraded to HD-split
+    bool m_pre_split;
 
     CKeyPool();
     CKeyPool(const CPubKey& vchPubKeyIn, bool internalIn);
@@ -181,6 +234,57 @@ public:
     }
 };
 
+/** A wrapper to reserve a key from a wallet keypool
+ *
+ * CReserveKey is used to reserve a key from the keypool. It is passed around
+ * during the CreateTransaction/CommitTransaction procedure.
+ *
+ * Instantiating a CReserveKey does not reserve a keypool key. To do so,
+ * GetReservedKey() needs to be called on the object. Once a key has been
+ * reserved, call KeepKey() on the CReserveKey object to make sure it is not
+ * returned to the keypool. Call ReturnKey() to return the key to the keypool
+ * so it can be re-used (for example, if the key was used in a new transaction
+ * and that transaction was not completed and needed to be aborted).
+ *
+ * If a key is reserved and KeepKey() is not called, then the key will be
+ * returned to the keypool when the CReserveObject goes out of scope.
+ */
+class CReserveKey
+{
+protected:
+    //! The wallet to reserve the keypool key from
+    CWallet* pwallet;
+    //! The index of the key in the keypool
+    int64_t nIndex{-1};
+    //! The public key
+    CPubKey vchPubKey;
+    //! Whether this is from the internal (change output) keypool
+    bool fInternal{false};
+
+public:
+    //! Construct a CReserveKey object. This does NOT reserve a key from the keypool yet
+    explicit CReserveKey(CWallet* pwalletIn)
+    {
+        pwallet = pwalletIn;
+    }
+
+    CReserveKey(const CReserveKey&) = delete;
+    CReserveKey& operator=(const CReserveKey&) = delete;
+
+    //! Destructor. If a key has been reserved and not KeepKey'ed, it will be returned to the keypool
+    ~CReserveKey()
+    {
+        ReturnKey();
+    }
+
+    //! Reserve a key from the keypool
+    bool GetReservedKey(CPubKey &pubkey, bool internal = false);
+    //! Return a key to the keypool
+    void ReturnKey();
+    //! Keep the key. Do not return it to the keypool when this object goes out of scope
+    void KeepKey();
+};
+
 /** Address book data */
 class CAddressBookData
 {
@@ -369,24 +473,11 @@ public:
     std::multimap<int64_t, CWalletTx*>::const_iterator m_it_wtxOrdered;
 
     // memory only
-    mutable bool fDebitCached;
-    mutable bool fCreditCached;
-    mutable bool fImmatureCreditCached;
-    mutable bool fAvailableCreditCached;
-    mutable bool fWatchDebitCached;
-    mutable bool fWatchCreditCached;
-    mutable bool fImmatureWatchCreditCached;
-    mutable bool fAvailableWatchCreditCached;
+    enum AmountType { DEBIT, CREDIT, IMMATURE_CREDIT, AVAILABLE_CREDIT, AMOUNTTYPE_ENUM_ELEMENTS };
+    CAmount GetCachableAmount(AmountType type, const isminefilter& filter, bool recalculate = false) const;
+    mutable CachableAmount m_amounts[AMOUNTTYPE_ENUM_ELEMENTS];
     mutable bool fChangeCached;
     mutable bool fInMempool;
-    mutable CAmount nDebitCached;
-    mutable CAmount nCreditCached;
-    mutable CAmount nImmatureCreditCached;
-    mutable CAmount nAvailableCreditCached;
-    mutable CAmount nWatchDebitCached;
-    mutable CAmount nWatchCreditCached;
-    mutable CAmount nImmatureWatchCreditCached;
-    mutable CAmount nAvailableWatchCreditCached;
     mutable CAmount nChangeCached;
 
     CWalletTx(const CWallet* pwalletIn, CTransactionRef arg) : CMerkleTx(std::move(arg))
@@ -403,24 +494,8 @@ public:
         nTimeReceived = 0;
         nTimeSmart = 0;
         fFromMe = false;
-        fDebitCached = false;
-        fCreditCached = false;
-        fImmatureCreditCached = false;
-        fAvailableCreditCached = false;
-        fWatchDebitCached = false;
-        fWatchCreditCached = false;
-        fImmatureWatchCreditCached = false;
-        fAvailableWatchCreditCached = false;
         fChangeCached = false;
         fInMempool = false;
-        nDebitCached = 0;
-        nCreditCached = 0;
-        nImmatureCreditCached = 0;
-        nAvailableCreditCached = 0;
-        nWatchDebitCached = 0;
-        nWatchCreditCached = 0;
-        nAvailableWatchCreditCached = 0;
-        nImmatureWatchCreditCached = 0;
         nChangeCached = 0;
         nOrderPos = -1;
     }
@@ -464,14 +539,10 @@ public:
     //! make sure balances are recalculated
     void MarkDirty()
     {
-        fCreditCached = false;
-        fAvailableCreditCached = false;
-        fImmatureCreditCached = false;
-        fWatchDebitCached = false;
-        fWatchCreditCached = false;
-        fAvailableWatchCreditCached = false;
-        fImmatureWatchCreditCached = false;
-        fDebitCached = false;
+        m_amounts[DEBIT].Reset();
+        m_amounts[CREDIT].Reset();
+        m_amounts[IMMATURE_CREDIT].Reset();
+        m_amounts[AVAILABLE_CREDIT].Reset();
         fChangeCached = false;
     }
 
@@ -623,6 +694,8 @@ class CWallet final : public CCryptoKeyStore, private interfaces::Chain::Notific
 private:
     std::atomic<bool> fAbortRescan{false};
     std::atomic<bool> fScanningWallet{false}; // controlled by WalletRescanReserver
+    std::atomic<int64_t> m_scanning_start{0};
+    std::atomic<double> m_scanning_progress{0};
     std::mutex mutexScanning;
     friend class WalletRescanReserver;
 
@@ -720,7 +793,7 @@ private:
      * to have seen all transactions in the chain, but is only used to track
      * live BlockConnected callbacks.
      */
-    uint256 m_last_block_processed;
+    uint256 m_last_block_processed GUARDED_BY(cs_wallet);
 
 public:
     /*
@@ -847,6 +920,8 @@ public:
     void AbortRescan() { fAbortRescan = true; }
     bool IsAbortingRescan() { return fAbortRescan; }
     bool IsScanning() { return fScanningWallet; }
+    int64_t ScanningDuration() const { return fScanningWallet ? GetTimeMillis() - m_scanning_start : 0; }
+    double ScanningProgress() const { return fScanningWallet ? (double) m_scanning_progress : 0; }
 
     /**
      * keystore implementation
@@ -898,7 +973,7 @@ public:
     bool ChangeWalletPassphrase(const SecureString& strOldWalletPassphrase, const SecureString& strNewWalletPassphrase);
     bool EncryptWallet(const SecureString& strWalletPassphrase);
 
-    void GetKeyBirthTimes(interfaces::Chain::Lock& locked_chain, std::map<CTxDestination, int64_t> &mapKeyBirth) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
+    void GetKeyBirthTimes(interfaces::Chain::Lock& locked_chain, std::map<CKeyID, int64_t> &mapKeyBirth) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     unsigned int ComputeTimeSmart(const CWalletTx& wtx) const;
 
     /**
@@ -989,6 +1064,8 @@ public:
     CFeeRate m_discard_rate{DEFAULT_DISCARD_FEE};
     OutputType m_default_address_type{DEFAULT_ADDRESS_TYPE};
     OutputType m_default_change_type{DEFAULT_CHANGE_TYPE};
+    /** Absolute maximum transaction fee (in satoshis) used by default for the wallet */
+    CAmount m_default_max_tx_fee{DEFAULT_TRANSACTION_MAXFEE};
 
     bool NewKeyPool();
     size_t KeypoolCountExternalKeys() EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
@@ -1222,34 +1299,6 @@ public:
  */
 void MaybeResendWalletTxs();
 
-/** A key allocated from the key pool. */
-class CReserveKey
-{
-protected:
-    CWallet* pwallet;
-    int64_t nIndex{-1};
-    CPubKey vchPubKey;
-    bool fInternal{false};
-
-public:
-    explicit CReserveKey(CWallet* pwalletIn)
-    {
-        pwallet = pwalletIn;
-    }
-
-    CReserveKey(const CReserveKey&) = delete;
-    CReserveKey& operator=(const CReserveKey&) = delete;
-
-    ~CReserveKey()
-    {
-        ReturnKey();
-    }
-
-    void ReturnKey();
-    bool GetReservedKey(CPubKey &pubkey, bool internal = false);
-    void KeepKey();
-};
-
 /** RAII object to check and reserve a wallet rescan */
 class WalletRescanReserver
 {
@@ -1266,6 +1315,8 @@ public:
         if (m_wallet->fScanningWallet) {
             return false;
         }
+        m_wallet->m_scanning_start = GetTimeMillis();
+        m_wallet->m_scanning_progress = 0;
         m_wallet->fScanningWallet = true;
         m_could_reserve = true;
         return true;