Key pool: Change ReturnDestination interface to take address instead of key

In order for ScriptPubKeyMan to be generic and work with future
ScriptPubKeyMans, ScriptPubKeyMan::ReturnDestination is changed to
take a CTxDestination instead of a CPubKey. Since LegacyScriptPubKeyMan
still deals with keys internally, a new map m_reserved_key_to_index is
added in order to track the keypool indexes that have been reserved.

The CPubKey argument of KeepDestination is also  removed so that it is
more generic. Instead of taking a CPubKey or a CTxDestination, we just use
the nIndex given to find the pubkey.

1 files changed, 6 insertions, 4 deletions

diff --git a/src/wallet/scriptpubkeyman.h b/src/wallet/scriptpubkeyman.h
index bcc62ece1e..6ed9a4787a 100644
--- a/src/wallet/scriptpubkeyman.h
+++ b/src/wallet/scriptpubkeyman.h
@@ -151,8 +151,8 @@ public:
     virtual isminetype IsMine(const CScript& script) const { return ISMINE_NO; }
 
     virtual bool GetReservedDestination(const OutputType type, bool internal, CTxDestination& address, int64_t& index, CKeyPool& keypool) { return false; }
-    virtual void KeepDestination(int64_t index, const OutputType& type, const CPubKey& pubkey) {}
-    virtual void ReturnDestination(int64_t index, bool internal, const CPubKey& pubkey) {}
+    virtual void KeepDestination(int64_t index, const OutputType& type) {}
+    virtual void ReturnDestination(int64_t index, bool internal, const CTxDestination& addr) {}
 
     virtual bool TopUp(unsigned int size = 0) { return false; }
 
@@ -246,6 +246,8 @@ private:
     std::set<int64_t> set_pre_split_keypool GUARDED_BY(cs_wallet);
     int64_t m_max_keypool_index GUARDED_BY(cs_wallet) = 0;
     std::map<CKeyID, int64_t> m_pool_key_to_index;
+    // Tracks keypool indexes to CKeyIDs of keys that have been taken out of the keypool but may be returned to it
+    std::map<int64_t, CKeyID> m_index_to_reserved_key;
 
     //! Fetches a key from the keypool
     bool GetKeyFromPool(CPubKey &key, const OutputType type, bool internal = false);
@@ -274,8 +276,8 @@ public:
     bool EncryptKeys(CKeyingMaterial& vMasterKeyIn);
 
     bool GetReservedDestination(const OutputType type, bool internal, CTxDestination& address, int64_t& index, CKeyPool& keypool) override;
-    void KeepDestination(int64_t index, const OutputType& type, const CPubKey& pubkey) override;
-    void ReturnDestination(int64_t index, bool internal, const CPubKey& pubkey) override;
+    void KeepDestination(int64_t index, const OutputType& type) override;
+    void ReturnDestination(int64_t index, bool internal, const CTxDestination&) override;
 
     bool TopUp(unsigned int size = 0) override;