Add support for watch-only addresses

Changes:
* Add Add/Have WatchOnly methods to CKeyStore, and implementations
  in CBasicKeyStore.
* Add similar methods to CWallet, and support entries for it in
  CWalletDB.
* Make IsMine in script/wallet return a new enum 'isminetype',
  rather than a boolean. This allows distinguishing between
  spendable and unspendable coins.
* Add a field fSpendable to COutput (GetAvailableCoins' return type).
* Mark watchonly coins in listunspent as 'watchonly': true.
* Add 'watchonly' to validateaddress, suppressing script/pubkey/...
  in this case.

Based on a patch by Eric Lombrozo.

Conflicts:
	src/qt/walletmodel.cpp
	src/rpcserver.cpp
	src/wallet.cpp

1 files changed, 19 insertions, 0 deletions

diff --git a/src/keystore.h b/src/keystore.h
index 79d8661aca..90fc3a4c7b 100644
--- a/src/keystore.h
+++ b/src/keystore.h
@@ -8,11 +8,21 @@
 
 #include "key.h"
 #include "sync.h"
+#include "script.h"     // for CNoDestination
 
 #include <boost/signals2/signal.hpp>
+#include <boost/variant.hpp>
 
 class CScript;
 
+/** A txout script template with a specific destination. It is either:
+ *  * CNoDestination: no destination set
+ *  * CKeyID: TX_PUBKEYHASH destination
+ *  * CScriptID: TX_SCRIPTHASH destination
+ *  A CTxDestination is the internal data type encoded in a CBitcoinAddress
+ */
+typedef boost::variant<CNoDestination, CKeyID, CScriptID> CTxDestination;
+
 /** A virtual base class for key stores */
 class CKeyStore
 {
@@ -36,10 +46,15 @@ public:
     virtual bool AddCScript(const CScript& redeemScript) =0;
     virtual bool HaveCScript(const CScriptID &hash) const =0;
     virtual bool GetCScript(const CScriptID &hash, CScript& redeemScriptOut) const =0;
+
+    // Support for Watch-only addresses
+    virtual bool AddWatchOnly(const CTxDestination &dest) =0;
+    virtual bool HaveWatchOnly(const CTxDestination &dest) const =0;
 };
 
 typedef std::map<CKeyID, CKey> KeyMap;
 typedef std::map<CScriptID, CScript > ScriptMap;
+typedef std::set<CTxDestination> WatchOnlySet;
 
 /** Basic key store, that keeps keys in an address->secret map */
 class CBasicKeyStore : public CKeyStore
@@ -47,6 +62,7 @@ class CBasicKeyStore : public CKeyStore
 protected:
     KeyMap mapKeys;
     ScriptMap mapScripts;
+    WatchOnlySet setWatchOnly;
 
 public:
     bool AddKeyPubKey(const CKey& key, const CPubKey &pubkey);
@@ -88,6 +104,9 @@ public:
     virtual bool AddCScript(const CScript& redeemScript);
     virtual bool HaveCScript(const CScriptID &hash) const;
     virtual bool GetCScript(const CScriptID &hash, CScript& redeemScriptOut) const;
+
+    virtual bool AddWatchOnly(const CTxDestination &dest);
+    virtual bool HaveWatchOnly(const CTxDestination &dest) const;
 };
 
 typedef std::vector<unsigned char, secure_allocator<unsigned char> > CKeyingMaterial;