Improve vote counting implementation #533

libraries/chain/db_maint.cpp

@@ -28,6 +28,7 @@
 #include <fc/uint128.hpp>
 
 #include <graphene/chain/database.hpp>
+#include <graphene/chain/hardfork.hpp>
 
 #include <graphene/chain/account_object.hpp>
 #include <graphene/chain/asset_object.hpp>
@@ -36,6 +37,7 @@
 #include <graphene/chain/committee_member_object.hpp>
 #include <graphene/chain/global_property_object.hpp>
 #include <graphene/chain/vesting_balance_object.hpp>
+#include <graphene/chain/vote_count.hpp>
 #include <graphene/chain/witness_object.hpp>
 #include <graphene/chain/worker_object.hpp>
 
@@ -183,7 +185,10 @@ void database::update_active_witnesses()
    }
 
    // Update witness authority
-   modify( get(GRAPHENE_WITNESS_ACCOUNT), [&]( account_object& a ) {
+   modify( get(GRAPHENE_WITNESS_ACCOUNT), [&]( account_object& a )
+   {
+      if( head_block_time() < HARDFORK_533_TIME )
+      {
       uint64_t total_votes = 0;
       map<account_id_type, uint64_t> weights;
       a.active.weight_threshold = 0;
@@ -208,7 +213,15 @@ void database::update_active_witnesses()
 
       a.active.weight_threshold /= 2;
       a.active.weight_threshold += 1;
-   });
+      }
+      else
+      {
+         vote_counter vc;
+         for( const witness_object& wit : wits )
+            vc.add( wit.witness_account, _vote_tally_buffer[wit.vote_id] );
+         vc.finish( a.active );
+      }
+   } );
 
    modify(gpo, [&]( global_property_object& gp ){
       gp.active_witnesses.clear();
@@ -256,7 +269,10 @@ void database::update_active_committee_members()
    // Update committee authorities
    if( !committee_members.empty() )
    {
-      modify(get(GRAPHENE_COMMITTEE_ACCOUNT), [&](account_object& a) {
+      modify(get(GRAPHENE_COMMITTEE_ACCOUNT), [&](account_object& a)
+      {
+         if( head_block_time() < HARDFORK_533_TIME )
+         {
          uint64_t total_votes = 0;
          map<account_id_type, uint64_t> weights;
          a.active.weight_threshold = 0;
@@ -281,7 +297,15 @@ void database::update_active_committee_members()
 
          a.active.weight_threshold /= 2;
          a.active.weight_threshold += 1;
-      });
+         }
+         else
+         {
+            vote_counter vc;
+            for( const committee_member_object& cm : committee_members )
+               vc.add( cm.committee_member_account, _vote_tally_buffer[cm.vote_id] );
+            vc.finish( a.active );
+         }
+      } );
       modify(get(GRAPHENE_RELAXED_COMMITTEE_ACCOUNT), [&](account_object& a) {
          a.active = get(GRAPHENE_COMMITTEE_ACCOUNT).active;
       });

libraries/chain/hardfork.d/533.hf

@@ -0,0 +1,4 @@
+// #533 Improve vote counting implementation
+#ifndef HARDFORK_533_TIME
+#define HARDFORK_533_TIME (fc::time_point_sec( 1455127200 ))
+#endif

libraries/chain/include/graphene/chain/vote_count.hpp

@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2015 Cryptonomex, Inc., and contributors.
+ *
+ * The MIT License
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+#include <graphene/chain/protocol/authority.hpp>
+
+namespace graphene { namespace chain {
+
+/**
+ * Keep track of vote totals in internal authority object.  See #533.
+ */
+struct vote_counter
+{
+   template< typename Component >
+   void add( Component who, uint64_t votes )
+   {
+      assert( votes <= last_votes );
+      last_votes = votes;
+      if( bitshift == -1 )
+         bitshift = std::max(int(boost::multiprecision::detail::find_msb( votes )) - 15, 0);
+      uint64_t scaled_votes = std::max( votes >> bitshift, uint64_t(1) );
+      assert( scaled_votes <= std::numeric_limits<weight_type>::max() );
+      total_votes += scaled_votes;
+      assert( total_votes <= std::numeric_limits<uint32_t>::max() );
+      auth.add_authority( who, weight_type( scaled_votes ) );
+   }
+
+   /**
+    * Write into out_auth, but only if we have at least one member.
+    */
+   void finish( authority& out_auth )
+   {
+      if( total_votes == 0 )
+         return;
+      assert( total_votes <= std::numeric_limits<uint32_t>::max() );
+      uint32_t weight = uint32_t( total_votes );
+      weight = (weight >> 1)+1;
+      auth.weight_threshold = weight;
+      out_auth = auth;
+   }
+
+   uint64_t last_votes = std::numeric_limits<uint64_t>::max();
+   uint64_t total_votes = 0;
+   int8_t bitshift = -1;
+   authority auth;
+};
+
+} } // graphene::chain