1 files changed, 31 insertions, 4 deletions
diff --git a/src/wallet/scriptpubkeyman.h b/src/wallet/scriptpubkeyman.h
index 7e15042950..c62c970235 100644
--- a/src/wallet/scriptpubkeyman.h
+++ b/src/wallet/scriptpubkeyman.h
@@ -18,6 +18,8 @@
 
 #include <boost/signals2/signal.hpp>
 
+#include <unordered_map>
+
 enum class OutputType;
 struct bilingual_str;
 
@@ -144,6 +146,17 @@ public:
     }
 };
 
+class KeyIDHasher
+{
+public:
+    KeyIDHasher() {}
+
+    size_t operator()(const CKeyID& id) const
+    {
+        return id.GetUint64(0);
+    }
+};
+
 /*
  * A class implementing ScriptPubKeyMan manages some (or all) scriptPubKeys used in a wallet.
  * It contains the scripts and keys related to the scriptPubKeys it manages.
@@ -288,10 +301,11 @@ private:
     bool AddKeyOriginWithDB(WalletBatch& batch, const CPubKey& pubkey, const KeyOriginInfo& info);
 
     /* the HD chain data model (external chain counters) */
-    CHDChain hdChain;
+    CHDChain m_hd_chain;
+    std::unordered_map<CKeyID, CHDChain, KeyIDHasher> m_inactive_hd_chains;
 
     /* HD derive new child key (on internal or external chain) */
-    void DeriveNewChildKey(WalletBatch& batch, CKeyMetadata& metadata, CKey& secret, bool internal = false) EXCLUSIVE_LOCKS_REQUIRED(cs_KeyStore);
+    void DeriveNewChildKey(WalletBatch& batch, CKeyMetadata& metadata, CKey& secret, CHDChain& hd_chain, bool internal = false) EXCLUSIVE_LOCKS_REQUIRED(cs_KeyStore);
 
     std::set<int64_t> setInternalKeyPool GUARDED_BY(cs_KeyStore);
     std::set<int64_t> setExternalKeyPool GUARDED_BY(cs_KeyStore);
@@ -320,6 +334,18 @@ private:
      */
     bool ReserveKeyFromKeyPool(int64_t& nIndex, CKeyPool& keypool, bool fRequestedInternal);
 
+    /**
+     * Like TopUp() but adds keys for inactive HD chains.
+     * Ensures that there are at least -keypool number of keys derived after the given index.
+     *
+     * @param seed_id the CKeyID for the HD seed.
+     * @param index the index to start generating keys from
+     * @param internal whether the internal chain should be used. true for internal chain, false for external chain.
+     *
+     * @return true if seed was found and keys were derived. false if unable to derive seeds
+     */
+    bool TopUpInactiveHDChain(const CKeyID seed_id, int64_t index, bool internal);
+
 public:
     using ScriptPubKeyMan::ScriptPubKeyMan;
 
@@ -393,11 +419,12 @@ public:
     void LoadKeyMetadata(const CKeyID& keyID, const CKeyMetadata &metadata);
     void LoadScriptMetadata(const CScriptID& script_id, const CKeyMetadata &metadata);
     //! Generate a new key
-    CPubKey GenerateNewKey(WalletBatch& batch, bool internal = false) EXCLUSIVE_LOCKS_REQUIRED(cs_KeyStore);
+    CPubKey GenerateNewKey(WalletBatch& batch, CHDChain& hd_chain, bool internal = false) EXCLUSIVE_LOCKS_REQUIRED(cs_KeyStore);
 
     /* Set the HD chain model (chain child index counters) */
     void SetHDChain(const CHDChain& chain, bool memonly);
-    const CHDChain& GetHDChain() const { return hdChain; }
+    const CHDChain& GetHDChain() const { return m_hd_chain; }
+    void AddInactiveHDChain(const CHDChain& chain);
 
     //! Adds a watch-only address to the store, without saving it to disk (used by LoadWallet)
     bool LoadWatchOnly(const CScript &dest);