wallet: generate keys ahead of use so a backup outlives the next block (#85)

The wallet made a key per address and per block mined, so a backup only ever
contained the keys that existed the moment it was taken -- mine one block and
the coin lands on a key the backup has never heard of. The README warned about
it, which is an admission rather than a fix.

Keys are now generated a hundred at a time and handed out one at a time, each
written to wallet.dat before it can be pointed at. A backup covers the next
hundred addresses. Deterministic derivation (#47) stays open; this buys back the
distance between a backup and the next mistake.

1 files changed, 8 insertions, 0 deletions

diff --git a/src/db.cpp b/src/db.cpp
index a503cae..3af87fb 100644
--- a/src/db.cpp
+++ b/src/db.cpp
@@ -636,6 +636,14 @@ bool CWalletDB::LoadWallet(vector<unsigned char>& vchDefaultKeyRet)
             {
                 ssValue >> vchDefaultKeyRet;
             }
+            else if (strType == "pool")
+            {
+                int64 nIndex;
+                ssKey >> nIndex;
+                vector<unsigned char> vchPubKey;
+                ssValue >> vchPubKey;
+                mapKeyPool[nIndex] = vchPubKey;
+            }
             else if (strType == "setting")  /// or settings or option or options or config?
             {
                 string strKey;