Block dust spam tx from mempool before fork point.

Don't accept dust spam tx to the mempool even before the fork point.
Blocks with them are still considered valid, though.

src/main.cpp

@@ -1191,9 +1191,11 @@ CTransaction::ConnectInputs (DatabaseSet& dbset,
 
             /* Check for unspendable outputs.  This is redundant for some
                of the checks done in IsUnspendable, but it also takes care
-               of blocking dust spam.  */
+               of blocking dust spam.  If not validating blocks (i. e., miner
+               or mempool), we are strict and block dust even before
+               the hardfork point.  */
             if (IsUnspendable (txPrev->vout[prevout.n], prevHeight,
-                               pindexBlock->nHeight))
+                               pindexBlock->nHeight, !fBlock))
               return error ("ConnectInputs: previous txo is unspendable");
 
             // If prev is coinbase, check that it's matured

src/main.h

@@ -145,8 +145,11 @@ bool GetTransaction(const uint256 &hash, CTransaction &txOut, uint256 &hashBlock
 /* Check if a transaction is unspendable.  Either because it is provably
    prunable, or because it is explicitly blocked due to some rule.  nHeight
    is the height at which (or later) it will be spent, and nPrevHeight
-   is the one where it is included in the block chain.  */
-bool IsUnspendable (const CTxOut& txo, int nPrevHeight, int nHeight);
+   is the one where it is included in the block chain.  The strict parameter
+   can be turned on for mempool validation (as opposed to blocks) to
+   reject transactions from the mempool even before a hardfork.  */
+bool IsUnspendable (const CTxOut& txo, int nPrevHeight,
+                    int nHeight, bool strict);
 
 
 

src/namecoin.cpp

@@ -1937,7 +1937,7 @@ int64 GetNameNetFee(const CTransaction& tx)
 }
 
 bool
-IsUnspendable (const CTxOut& txo, int nPrevHeight, int nHeight)
+IsUnspendable (const CTxOut& txo, int nPrevHeight, int nHeight, bool strict)
 {
   assert (nPrevHeight <= nHeight);
 
@@ -1951,7 +1951,7 @@ IsUnspendable (const CTxOut& txo, int nPrevHeight, int nHeight)
      set.  We block all 1-Swartz outputs created between blocks 39k and 41k.
      Blocking takes effect at the softfork height.  */
   if (txo.nValue == 1 && nPrevHeight >= 39000 && nPrevHeight <= 41000
-      && nHeight >= FORK_HEIGHT_DUSTSPAM)
+      && (strict || nHeight >= FORK_HEIGHT_DUSTSPAM))
     return true;
 
   /* A name_update or name_firstupdate is unspendable if expired.  */