wallet: filter for keys only before record deser in salvage

When salvaging a wallet, avoid deserializing any records that we don't
care about, i.e. filter for keys only before the deserialization.

Author: achow101

src/wallet/salvage.cpp

@@ -16,6 +16,11 @@ static const char *HEADER_END = "HEADER=END";
 static const char *DATA_END = "DATA=END";
 typedef std::pair<std::vector<unsigned char>, std::vector<unsigned char> > KeyValPair;
 
+static bool KeyFilter(const std::string& type)
+{
+    return WalletBatch::IsKeyType(type) || type == DBKeys::HDCHAIN;
+}
+
 bool RecoverDatabaseFile(const fs::path& file_path, bilingual_str& error, std::vector<bilingual_str>& warnings)
 {
     std::string filename;
@@ -129,9 +134,9 @@ bool RecoverDatabaseFile(const fs::path& file_path, bilingual_str& error, std::v
         {
             // Required in LoadKeyMetadata():
             LOCK(dummyWallet.cs_wallet);
-            fReadOK = ReadKeyValue(&dummyWallet, ssKey, ssValue, strType, strErr);
+            fReadOK = ReadKeyValue(&dummyWallet, ssKey, ssValue, strType, strErr, KeyFilter);
         }
-        if (!WalletBatch::IsKeyType(strType) && strType != DBKeys::HDCHAIN) {
+        if (!KeyFilter(strType)) {
             continue;
         }
         if (!fReadOK)