HF: Dyanfed pruned header now has extra root

Author: instagibbs

src/dynafed.cpp

@@ -94,7 +94,7 @@ DynaFedParamEntry ComputeNextBlockCurrentParameters(const CBlockIndex* pindexPre
     // Return appropriate format based on epoch age
     if (epoch_age > 0) {
         // TODO implement "prune" function to remove fields in place and change serialize type
-        return DynaFedParamEntry(entry.m_signblockscript, entry.m_signblock_witness_limit);
+        return DynaFedParamEntry(entry.m_signblockscript, entry.m_signblock_witness_limit, entry.CalculateExtraRoot());
     } else {
         return entry;
     }

src/miner.cpp

@@ -151,8 +151,8 @@ std::unique_ptr<CBlockTemplate> BlockAssembler::CreateNewBlock(const CScript& sc
     fIncludeWitness = IsWitnessEnabled(pindexPrev, chainparams.GetConsensus());
 
     if (IsDynaFedEnabled(pindexPrev, chainparams.GetConsensus())) {
-        DynaFedParamEntry current_params = ComputeNextBlockCurrentParameters(chainActive.Tip(), chainparams.GetConsensus());
-        DynaFedParams block_params(current_params, proposed_entry ? *proposed_entry : DynaFedParamEntry());
+        const DynaFedParamEntry current_params = ComputeNextBlockCurrentParameters(chainActive.Tip(), chainparams.GetConsensus());
+        const DynaFedParams block_params(current_params, proposed_entry ? *proposed_entry : DynaFedParamEntry());
         pblock->m_dynafed_params = block_params;
         nBlockWeight += ::GetSerializeSize(block_params, PROTOCOL_VERSION)*WITNESS_SCALE_FACTOR;
         nBlockWeight += current_params.m_signblock_witness_limit; // Note witness discount

src/primitives/block.cpp

@@ -43,19 +43,39 @@ std::string CBlock::ToString() const
 
 uint256 DynaFedParamEntry::CalculateRoot() const
 {
-    if (IsNull()) {
+    if (m_serialize_type == 0) {
         return uint256();
     }
 
+    std::vector<uint256> compact_leaves;
+    compact_leaves.push_back(SerializeHash(m_signblockscript, SER_GETHASH, 0));
+    compact_leaves.push_back(SerializeHash(m_signblock_witness_limit, SER_GETHASH, 0));
+    uint256 compact_root(ComputeFastMerkleRoot(compact_leaves));
+
+    uint256 extra_root;
+    if (m_serialize_type ==1 ) {
+        // It's pruned, take the stored value
+        extra_root = m_elided_root;
+    } else if (m_serialize_type == 2) {
+        // It's unpruned, compute the node value
+        extra_root = CalculateExtraRoot();
+    }
+
     std::vector<uint256> leaves;
-    leaves.push_back(SerializeHash(m_signblockscript, SER_GETHASH, 0));
-    leaves.push_back(SerializeHash(m_signblock_witness_limit, SER_GETHASH, 0));
-    leaves.push_back(SerializeHash(m_fedpeg_program, SER_GETHASH, 0));
-    leaves.push_back(SerializeHash(m_fedpegscript, SER_GETHASH, 0));
-    leaves.push_back(SerializeHash(m_extension_space, SER_GETHASH, 0));
+    leaves.push_back(compact_root);
+    leaves.push_back(extra_root);
     return ComputeFastMerkleRoot(leaves);
 }
 
+uint256 DynaFedParamEntry::CalculateExtraRoot() const
+{
+    std::vector<uint256> extra_leaves;
+    extra_leaves.push_back(SerializeHash(m_fedpeg_program, SER_GETHASH, 0));
+    extra_leaves.push_back(SerializeHash(m_fedpegscript, SER_GETHASH, 0));
+    extra_leaves.push_back(SerializeHash(m_extension_space, SER_GETHASH, 0));
+    return ComputeFastMerkleRoot(extra_leaves);
+}
+
 uint256 DynaFedParams::CalculateRoot() const
 {
     if (IsNull()) {

src/primitives/block.h

@@ -64,12 +64,13 @@ class DynaFedParamEntry
     CScript m_fedpeg_program; // The "scriptPubKey" of the fedpegscript
     CScript m_fedpegscript; // The witnessScript for witness v0 or undefined otherwise.
     // No consensus meaning to the particular bytes, currently we interpret as PAK keys, details in pak.h
-    std::vector<std::vector<unsigned char>> m_extension_space;
+    std::vector<std::vector<unsigned char>> m_extension_space;\
+    uint256 m_elided_root; // non-zero only when m_serialize_type == 1
 
     // Each constructor sets its own serialization type implicitly based on which
     // arguments are given
     DynaFedParamEntry() { m_signblock_witness_limit = 0; m_serialize_type = 0; };
-    DynaFedParamEntry(const CScript& signblockscript_in, const uint32_t sbs_wit_limit_in) : m_signblockscript(signblockscript_in), m_signblock_witness_limit(sbs_wit_limit_in) { m_serialize_type = 1; };
+    DynaFedParamEntry(const CScript& signblockscript_in, const uint32_t sbs_wit_limit_in, const uint256 elided_root_in) : m_signblockscript(signblockscript_in), m_signblock_witness_limit(sbs_wit_limit_in), m_elided_root(elided_root_in) { m_serialize_type = 1; };
     DynaFedParamEntry(const CScript& signblockscript_in, const uint32_t sbs_wit_limit_in, const CScript& fedpeg_program_in, const CScript& fedpegscript_in, const std::vector<std::vector<unsigned char>> extension_space_in) : m_signblockscript(signblockscript_in), m_signblock_witness_limit(sbs_wit_limit_in), m_fedpeg_program(fedpeg_program_in), m_fedpegscript(fedpegscript_in), m_extension_space(extension_space_in) { m_serialize_type = 2; };
 
     ADD_SERIALIZE_METHODS;
@@ -84,6 +85,7 @@ class DynaFedParamEntry
             case 1:
                 READWRITE(m_signblockscript);
                 READWRITE(m_signblock_witness_limit);
+                READWRITE(m_elided_root);
                 break;
             case 2:
                 READWRITE(m_signblockscript);
@@ -98,6 +100,8 @@ class DynaFedParamEntry
     }
 
     uint256 CalculateRoot() const;
+    // Calculates root for the non-blocksigning merkle fields
+    uint256 CalculateExtraRoot() const;
 
     bool IsNull() const
     {

src/test/dynafed_tests.cpp

@@ -21,7 +21,7 @@ BOOST_AUTO_TEST_CASE(dynafed_params_root)
     CScript fp_script(opcodetype(4));
     std::vector<std::vector<unsigned char>> ext{ {5, 6}, {7} };
 
-    DynaFedParamEntry compact_entry = DynaFedParamEntry(signblockscript, signblock_wl);
+    DynaFedParamEntry compact_entry = DynaFedParamEntry(signblockscript, signblock_wl, uint256());
     BOOST_CHECK_EQUAL(
         compact_entry.CalculateRoot().GetHex(),
         "dff5f3793abc06a6d75e80fe3cfd47406f732fa4ec9305960ae2a229222a1ad5"