Merge pull request #27 from wowario/median_timestamp

Use median timestamp if current time renders a block invalid.

src/cryptonote_core/blockchain.cpp

@@ -1141,6 +1141,12 @@ bool Blockchain::create_block_template(block& b, const account_public_address& m
   b.prev_id = get_tail_id();
   b.timestamp = time(NULL);
 
+  uint64_t median_ts;
+  if (!check_block_timestamp(b, median_ts))
+  {
+    b.timestamp = median_ts;
+  }
+
   diffic = get_difficulty_for_next_block();
   CHECK_AND_ASSERT_MES(diffic, false, "difficulty overhead.");
 
@@ -3126,10 +3132,10 @@ uint64_t Blockchain::get_adjusted_time() const
 }
 //------------------------------------------------------------------
 //TODO: revisit, has changed a bit on upstream
-bool Blockchain::check_block_timestamp(std::vector<uint64_t>& timestamps, const block& b) const
+bool Blockchain::check_block_timestamp(std::vector<uint64_t>& timestamps, const block& b, uint64_t& median_ts) const
 {
   LOG_PRINT_L3("Blockchain::" << __func__);
-  uint64_t median_ts = epee::misc_utils::median(timestamps);
+  median_ts = epee::misc_utils::median(timestamps);
 
   if(b.timestamp < median_ts)
   {
@@ -3147,7 +3153,7 @@ bool Blockchain::check_block_timestamp(std::vector<uint64_t>& timestamps, const
 //   true if the block's timestamp is not less than the timestamp of the
 //       median of the selected blocks
 //   false otherwise
-bool Blockchain::check_block_timestamp(const block& b) const
+bool Blockchain::check_block_timestamp(const block& b, uint64_t& median_ts) const
 {
   LOG_PRINT_L3("Blockchain::" << __func__);
   uint64_t cryptonote_block_future_time_limit = get_current_hard_fork_version() < 7 ? CRYPTONOTE_BLOCK_FUTURE_TIME_LIMIT : CRYPTONOTE_BLOCK_FUTURE_TIME_LIMIT_V2;
@@ -3173,7 +3179,7 @@ bool Blockchain::check_block_timestamp(const block& b) const
     timestamps.push_back(m_db->get_block_timestamp(offset));
   }
 
-  return check_block_timestamp(timestamps, b);
+  return check_block_timestamp(timestamps, b, median_ts);
 }
 //------------------------------------------------------------------
 void Blockchain::return_tx_to_pool(std::vector<transaction> &txs)

src/cryptonote_core/blockchain.h

@@ -1291,10 +1291,12 @@ namespace cryptonote
      *   false otherwise
      *
      * @param b the block to be checked
+     * @param median_ts return-by-reference the median of timestamps
      *
      * @return true if the block's timestamp is valid, otherwise false
      */
-    bool check_block_timestamp(const block& b) const;
+    bool check_block_timestamp(const block& b, uint64_t& median_ts) const;
+    bool check_block_timestamp(const block& b) const { uint64_t median_ts; return check_block_timestamp(b, median_ts); }
 
     /**
      * @brief checks a block's timestamp
@@ -1307,7 +1309,8 @@ namespace cryptonote
      *
      * @return true if the block's timestamp is valid, otherwise false
      */
-    bool check_block_timestamp(std::vector<uint64_t>& timestamps, const block& b) const;
+    bool check_block_timestamp(std::vector<uint64_t>& timestamps, const block& b, uint64_t& median_ts) const;
+    bool check_block_timestamp(std::vector<uint64_t>& timestamps, const block& b) const { uint64_t median_ts; return check_block_timestamp(timestamps, b, median_ts); }
 
     /**
      * @brief get the "adjusted time"