Merge pull request #3370 from sipa/headersfirst3

Prepare block connection logic for headers-first

src/init.cpp

@@ -983,7 +983,7 @@ bool AppInit2(boost::thread_group& threadGroup)
 
     // scan for better chains in the block chain database, that are not yet connected in the active best chain
     CValidationState state;
-    if (!ConnectBestBlock(state))
+    if (!ActivateBestChain(state))
         strErrors << "Failed to connect best block";
 
     std::vector<boost::filesystem::path> vImportFiles;

src/main.h

@@ -165,10 +165,8 @@ bool IsInitialBlockDownload();
 std::string GetWarnings(std::string strFor);
 /** Retrieve a transaction (from memory pool, or from disk, if possible) */
 bool GetTransaction(const uint256 &hash, CTransaction &tx, uint256 &hashBlock, bool fAllowSlow = false);
-/** Connect/disconnect blocks until pindexNew is the new tip of the active block chain */
-bool SetBestChain(CValidationState &state, CBlockIndex* pindexNew);
 /** Find the best known block, and make it the tip of the block chain */
-bool ConnectBestBlock(CValidationState &state);
+bool ActivateBestChain(CValidationState &state);
 int64_t GetBlockValue(int nHeight, int64_t nFees);
 unsigned int GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlockHeader *pblock);
 
@@ -716,6 +714,8 @@ public:
     unsigned int nBits;
     unsigned int nNonce;
 
+    // (memory only) Sequencial id assigned to distinguish order in which blocks are received.
+    uint32_t nSequenceId;
 
     CBlockIndex()
     {
@@ -729,6 +729,7 @@ public:
         nTx = 0;
         nChainTx = 0;
         nStatus = 0;
+        nSequenceId = 0;
 
         nVersion       = 0;
         hashMerkleRoot = 0;
@@ -749,6 +750,7 @@ public:
         nTx = 0;
         nChainTx = 0;
         nStatus = 0;
+        nSequenceId = 0;
 
         nVersion       = block.nVersion;
         hashMerkleRoot = block.hashMerkleRoot;
@@ -958,23 +960,23 @@ public:
         AbortNode(msg);
         return Error();
     }
-    bool IsValid() {
+    bool IsValid() const {
         return mode == MODE_VALID;
     }
-    bool IsInvalid() {
+    bool IsInvalid() const {
         return mode == MODE_INVALID;
     }
-    bool IsError() {
+    bool IsError() const {
         return mode == MODE_ERROR;
     }
-    bool IsInvalid(int &nDoSOut) {
+    bool IsInvalid(int &nDoSOut) const {
         if (IsInvalid()) {
             nDoSOut = nDoS;
             return true;
         }
         return false;
     }
-    bool CorruptionPossible() {
+    bool CorruptionPossible() const {
         return corruptionPossible;
     }
     unsigned char GetRejectCode() const { return chRejectCode; }
@@ -1041,6 +1043,8 @@ public:
 /** The currently-connected chain of blocks. */
 extern CChain chainActive;
 
+/** The currently best known chain of headers (some of which may be invalid). */
+extern CChain chainMostWork;
 
 /** Global variable that points to the active CCoinsView (protected by cs_main) */
 extern CCoinsViewCache *pcoinsTip;