allow extra data in blocks

2 files changed, 16 insertions, 3 deletions

diff --git a/include/hotstuff/consensus.h b/include/hotstuff/consensus.h
index 1528b40..85c1e8c 100644
--- a/include/hotstuff/consensus.h
+++ b/include/hotstuff/consensus.h
@@ -80,7 +80,8 @@ class HotStuffCore {
      * contain at least one block, and the first block is the actual parent,
      * while the others are uncles/aunts */
     void on_propose(const std::vector<command_t> &cmds,
-                    const std::vector<block_t> &parents);
+                    const std::vector<block_t> &parents,
+                    serializable_bt &&extra = nullptr);
 
     /* Functions required to construct concrete instances for abstract classes.
      * */
@@ -113,6 +114,8 @@ class HotStuffCore {
     virtual quorum_cert_bt parse_quorum_cert(DataStream &s) = 0;
     /** Create a command object from its serialized form. */
     virtual command_t parse_cmd(DataStream &s) = 0;
+    /** Create the extra data from its serialized form. */
+    virtual serializable_bt parse_extra_block_data(DataStream &) { return nullptr; }
 
     public:
     /** Add a replica to the current configuration. This should only be called
diff --git a/include/hotstuff/entity.h b/include/hotstuff/entity.h
index 09b40aa..dc77c81 100644
--- a/include/hotstuff/entity.h
+++ b/include/hotstuff/entity.h
@@ -102,13 +102,17 @@ get_hashes(const std::vector<Hashable> &plist) {
     return std::move(hashes);
 }
 
+using serializable_bt = BoxObj<Serializable>;
+
 class Block {
     friend HotStuffCore;
     std::vector<uint256_t> parent_hashes;
     std::vector<command_t> cmds;
     quorum_cert_bt qc;
-    uint256_t hash;
+    serializable_bt extra;
 
+    /* the following fields can be derived from above */
+    uint256_t hash;
     std::vector<block_t> parents;
     block_t qc_ref;
     quorum_cert_bt self_qc;
@@ -121,12 +125,14 @@ class Block {
     public:
     Block():
         qc(nullptr),
+        extra(nullptr),
         qc_ref(nullptr),
         self_qc(nullptr), height(0),
         delivered(false), decision(0) {}
 
     Block(bool delivered, int8_t decision):
         qc(nullptr),
+        extra(nullptr),
         hash(salticidae::get_hash(*this)),
         qc_ref(nullptr),
         self_qc(nullptr), height(0),
@@ -134,14 +140,16 @@ class Block {
 
     Block(const std::vector<block_t> &parents,
         const std::vector<command_t> &cmds,
-        uint32_t height,
         quorum_cert_bt &&qc,
+        serializable_bt &&extra,
+        uint32_t height,
         const block_t &qc_ref,
         quorum_cert_bt &&self_qc,
         int8_t decision = 0):
             parent_hashes(get_hashes(parents)),
             cmds(cmds),
             qc(std::move(qc)),
+            extra(std::move(extra)),
             hash(salticidae::get_hash(*this)),
             parents(parents),
             qc_ref(qc_ref),
@@ -185,6 +193,8 @@ class Block {
 
     const block_t &get_qc_ref() const { return qc_ref; }
 
+    const serializable_bt &get_extra() const { return extra; }
+
     operator std::string () const {
         DataStream s;
         s << "<block "