Add AllowMinDifficultyBlocks chain parameter

src/chainparams.cpp

@@ -224,6 +224,8 @@ public:
         base58Prefixes[EXT_PUBLIC_KEY] = list_of(0x04)(0x35)(0x87)(0xCF);
         base58Prefixes[EXT_SECRET_KEY] = list_of(0x04)(0x35)(0x83)(0x94);
     }
+
+    virtual bool AllowMinDifficultyBlocks() const { return true; }
     virtual Network NetworkID() const { return CChainParams::TESTNET; }
 };
 static CTestNetParams testNetParams;

src/chainparams.h

@@ -70,6 +70,8 @@ public:
     virtual bool MiningRequiresPeers() const { return true; }
     /* Default value for -checkmempool argument */
     virtual bool DefaultCheckMemPool() const { return false; }
+    /* Allow mining of a min-difficulty block */
+    virtual bool AllowMinDifficultyBlocks() const { return false; }
     const string& DataDir() const { return strDataDir; }
     /* Make miner stop after a block is found. In RPC, don't return
      * until nGenProcLimit blocks are generated */

src/main.cpp

@@ -1210,7 +1210,7 @@ unsigned int ComputeMinWork(unsigned int nBase, int64_t nTime)
     const uint256 &bnLimit = Params().ProofOfWorkLimit();
     // Testnet has min-difficulty blocks
     // after nTargetSpacing*2 time between blocks:
-    if (TestNet() && nTime > nTargetSpacing*2)
+    if (Params().AllowMinDifficultyBlocks() && nTime > nTargetSpacing*2)
         return bnLimit.GetCompact();
 
     uint256 bnResult;
@@ -1238,7 +1238,7 @@ unsigned int GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlockHead
     // Only change once per interval
     if ((pindexLast->nHeight+1) % nInterval != 0)
     {
-        if (TestNet())
+        if (Params().AllowMinDifficultyBlocks())
         {
             // Special difficulty rule for testnet:
             // If the new block's timestamp is more than 2* 10 minutes
@@ -1468,7 +1468,7 @@ void UpdateTime(CBlockHeader& block, const CBlockIndex* pindexPrev)
     block.nTime = max(pindexPrev->GetMedianTimePast()+1, GetAdjustedTime());
 
     // Updating time can change work required on testnet:
-    if (TestNet())
+    if (Params().AllowMinDifficultyBlocks())
         block.nBits = GetNextWorkRequired(pindexPrev, &block);
 }
 

src/miner.cpp

@@ -632,7 +632,7 @@ void static BitcoinMiner(CWallet *pwallet)
             // Update nTime every few seconds
             UpdateTime(*pblock, pindexPrev);
             nBlockTime = ByteReverse(pblock->nTime);
-            if (TestNet())
+            if (Params().AllowMinDifficultyBlocks())
             {
                 // Changing pblock->nTime can change work required on testnet:
                 nBlockBits = ByteReverse(pblock->nBits);