1 files changed, 31 insertions, 5 deletions

diff --git a/src/wallet.h b/src/wallet.h
index fea3297788..6a6ee0c4ab 100644
--- a/src/wallet.h
+++ b/src/wallet.h
@@ -14,6 +14,16 @@ class CWalletTx;
 class CReserveKey;
 class CWalletDB;
 
+enum WalletFeature
+{
+    FEATURE_BASE = 10500, // the earliest version new wallets supports (only useful for getinfo's clientversion output)
+
+    FEATURE_WALLETCRYPT = 40000, // wallet encryption
+    FEATURE_COMPRPUBKEY = 60000, // compressed public keys
+
+    FEATURE_LATEST = 60000
+};
+
 // A CWallet is an extension of a keystore, which also maintains a set of
 // transactions and balances, and provides the ability to create new
 // transactions
@@ -25,8 +35,12 @@ private:
 
     CWalletDB *pwalletdbEncryption;
 
+    // the current wallet version: clients below this version are not able to load the wallet
     int nWalletVersion;
 
+    // the maxmimum wallet format version: memory-only variable that specifies to what version this wallet may be upgraded
+    int nWalletMaxVersion;
+
 public:
     mutable CCriticalSection cs_wallet;
 
@@ -42,14 +56,16 @@ public:
 
     CWallet()
     {
-        nWalletVersion = 0;
+        nWalletVersion = FEATURE_BASE;
+        nWalletMaxVersion = FEATURE_BASE;
         fFileBacked = false;
         nMasterKeyMaxID = 0;
         pwalletdbEncryption = NULL;
     }
     CWallet(std::string strWalletFileIn)
     {
-        nWalletVersion = 0;
+        nWalletVersion = FEATURE_BASE;
+        nWalletMaxVersion = FEATURE_BASE;
         strWalletFile = strWalletFileIn;
         fFileBacked = true;
         nMasterKeyMaxID = 0;
@@ -65,6 +81,9 @@ public:
 
     std::vector<unsigned char> vchDefaultKey;
 
+    // check whether we are allowed to upgrade (or already support) to the named feature
+    bool CanSupportFeature(enum WalletFeature wf) { return nWalletMaxVersion >= wf; }
+
     // keystore implementation
     // Generate a new key
     std::vector<unsigned char> GenerateNewKey();
@@ -73,12 +92,12 @@ public:
     // Adds a key to the store, without saving it to disk (used by LoadWallet)
     bool LoadKey(const CKey& key) { return CCryptoKeyStore::AddKey(key); }
 
-    bool LoadMinVersion(int nVersion) { nWalletVersion = nVersion; return true; }
+    bool LoadMinVersion(int nVersion) { nWalletVersion = nVersion; nWalletMaxVersion = std::max(nWalletMaxVersion, nVersion); return true; }
 
     // Adds an encrypted key to the store, and saves it to disk.
     bool AddCryptedKey(const std::vector<unsigned char> &vchPubKey, const std::vector<unsigned char> &vchCryptedSecret);
     // Adds an encrypted key to the store, without saving it to disk (used by LoadWallet)
-    bool LoadCryptedKey(const std::vector<unsigned char> &vchPubKey, const std::vector<unsigned char> &vchCryptedSecret) { return CCryptoKeyStore::AddCryptedKey(vchPubKey, vchCryptedSecret); }
+    bool LoadCryptedKey(const std::vector<unsigned char> &vchPubKey, const std::vector<unsigned char> &vchCryptedSecret) { SetMinVersion(FEATURE_WALLETCRYPT); return CCryptoKeyStore::AddCryptedKey(vchPubKey, vchCryptedSecret); }
     bool AddCScript(const CScript& redeemScript);
     bool LoadCScript(const CScript& redeemScript) { return CCryptoKeyStore::AddCScript(redeemScript); }
 
@@ -216,7 +235,14 @@ public:
 
     bool SetDefaultKey(const std::vector<unsigned char> &vchPubKey);
 
-    bool SetMinVersion(int nVersion, CWalletDB* pwalletdbIn = NULL);
+    // signify that a particular wallet feature is now used. this may change nWalletVersion and nWalletMaxVersion if those are lower
+    bool SetMinVersion(enum WalletFeature, CWalletDB* pwalletdbIn = NULL, bool fExplicit = false);
+
+    // change which version we're allowed to upgrade to (note that this does not immediately imply upgrading to that format)
+    bool SetMaxVersion(int nVersion);
+
+    // get the current wallet format (the oldest client version guaranteed to understand this wallet)
+    int GetVersion() { return nWalletVersion; }
 };