BIP141: Commitment structure and deployment

Includes a fix by Suhas Daftuar and LongShao007

src/consensus/merkle.cpp

@@ -165,6 +165,17 @@ uint256 BlockMerkleRoot(const CBlock& block, bool* mutated)
     return ComputeMerkleRoot(leaves, mutated);
 }
 
+uint256 BlockWitnessMerkleRoot(const CBlock& block, bool* mutated)
+{
+    std::vector<uint256> leaves;
+    leaves.resize(block.vtx.size());
+    leaves[0].SetNull(); // The witness hash of the coinbase is 0.
+    for (size_t s = 1; s < block.vtx.size(); s++) {
+        leaves[s] = block.vtx[s].GetWitnessHash();
+    }
+    return ComputeMerkleRoot(leaves, mutated);
+}
+
 std::vector<uint256> BlockMerkleBranch(const CBlock& block, uint32_t position)
 {
     std::vector<uint256> leaves;

src/consensus/merkle.h

@@ -22,6 +22,12 @@ uint256 ComputeMerkleRootFromBranch(const uint256& leaf, const std::vector<uint2
  */
 uint256 BlockMerkleRoot(const CBlock& block, bool* mutated = NULL);
 
+/*
+ * Compute the Merkle root of the witness transactions in a block.
+ * *mutated is set to true if a duplicated subtree was found.
+ */
+uint256 BlockWitnessMerkleRoot(const CBlock& block, bool* mutated = NULL);
+
 /*
  * Compute the Merkle branch for the tree of transactions in a block, for a
  * given position.

src/consensus/params.h

@@ -16,6 +16,7 @@ enum DeploymentPos
 {
     DEPLOYMENT_TESTDUMMY,
     DEPLOYMENT_CSV, // Deployment of BIP68, BIP112, and BIP113.
+    DEPLOYMENT_SEGWIT, // Deployment of BIP141 and BIP143
     // NOTE: Also add new deployments to VersionBitsDeploymentInfo in versionbits.cpp
     MAX_VERSION_BITS_DEPLOYMENTS
 };

src/consensus/validation.h

@@ -77,6 +77,9 @@ public:
     bool CorruptionPossible() const {
         return corruptionPossible;
     }
+    void SetCorruptionPossible() {
+        corruptionPossible = true;
+    }
     unsigned int GetRejectCode() const { return chRejectCode; }
     std::string GetRejectReason() const { return strRejectReason; }
     std::string GetDebugMessage() const { return strDebugMessage; }