consensus, core/*, params: metropolis preparation refactor

This commit is a preparation for the upcoming metropolis hardfork. It
prepares the state, core and vm packages such that integration with
metropolis becomes less of a hassle.

* Difficulty calculation requires header instead of individual
  parameters
* statedb.StartRecord renamed to statedb.Prepare and added Finalise
  method required by metropolis, which removes unwanted accounts from
  the state (i.e. selfdestruct)
* State keeps record of destructed objects (in addition to dirty
  objects)
* core/vm pre-compiles may now return errors
* core/vm pre-compiles gas check now take the full byte slice as argument
  instead of just the size
* core/vm now keeps several hard-fork instruction tables instead of a
  single instruction table and removes the need for hard-fork checks in
  the instructions
* core/vm contains a empty restruction function which is added in
  preparation of metropolis write-only mode operations
* Adds the bn256 curve
* Adds and sets the metropolis chain config block parameters (2^64-1)

1 files changed, 15 insertions, 7 deletions

diff --git a/core/chain_makers.go b/core/chain_makers.go
index f34279ba0..967744282 100644
--- a/core/chain_makers.go
+++ b/core/chain_makers.go
@@ -84,7 +84,7 @@ func (b *BlockGen) AddTx(tx *types.Transaction) {
 	if b.gasPool == nil {
 		b.SetCoinbase(common.Address{})
 	}
-	b.statedb.StartRecord(tx.Hash(), common.Hash{}, len(b.txs))
+	b.statedb.Prepare(tx.Hash(), common.Hash{}, len(b.txs))
 	receipt, _, err := ApplyTransaction(b.config, nil, &b.header.Coinbase, b.gasPool, b.statedb, b.header, tx, b.header.GasUsed, vm.Config{})
 	if err != nil {
 		panic(err)
@@ -142,7 +142,7 @@ func (b *BlockGen) OffsetTime(seconds int64) {
 	if b.header.Time.Cmp(b.parent.Header().Time) <= 0 {
 		panic("block time out of range")
 	}
-	b.header.Difficulty = ethash.CalcDifficulty(b.config, b.header.Time.Uint64(), b.parent.Time().Uint64(), b.parent.Number(), b.parent.Difficulty())
+	b.header.Difficulty = ethash.CalcDifficulty(b.config, b.header.Time.Uint64(), b.parent.Header())
 }
 
 // GenerateChain creates a chain of n blocks. The first block's
@@ -209,15 +209,23 @@ func makeHeader(config *params.ChainConfig, parent *types.Block, state *state.St
 	} else {
 		time = new(big.Int).Add(parent.Time(), big.NewInt(10)) // block time is fixed at 10 seconds
 	}
+	parentHeader := parent.Header()
+	// adjust the parent time
+	parentHeader.Time = new(big.Int).Sub(time, big.NewInt(10))
+
 	return &types.Header{
 		Root:       state.IntermediateRoot(config.IsEIP158(parent.Number())),
 		ParentHash: parent.Hash(),
 		Coinbase:   parent.Coinbase(),
-		Difficulty: ethash.CalcDifficulty(config, time.Uint64(), new(big.Int).Sub(time, big.NewInt(10)).Uint64(), parent.Number(), parent.Difficulty()),
-		GasLimit:   CalcGasLimit(parent),
-		GasUsed:    new(big.Int),
-		Number:     new(big.Int).Add(parent.Number(), common.Big1),
-		Time:       time,
+		Difficulty: ethash.CalcDifficulty(config, time.Uint64(), &types.Header{
+			Number:     parent.Number(),
+			Time:       new(big.Int).Sub(time, big.NewInt(10)),
+			Difficulty: parent.Difficulty(),
+		}),
+		GasLimit: CalcGasLimit(parent),
+		GasUsed:  new(big.Int),
+		Number:   new(big.Int).Add(parent.Number(), common.Big1),
+		Time:     time,
 	}
 }