Changed prev_hash to block_hash, state transition now uses vm env

* PREVHASH => BLOCKHASH( N )
* State transition object uses VMEnv as it's query interface
* Updated vm.Enviroment has GetHash( n ) for BLOCKHASH instruction
* Added GetHash to xeth, core, utils & test environments

1 files changed, 10 insertions, 3 deletions

diff --git a/core/vm_env.go b/core/vm_env.go
index 4e0315ff3..624a63333 100644
--- a/core/vm_env.go
+++ b/core/vm_env.go
@@ -13,10 +13,12 @@ type VMEnv struct {
 	block *types.Block
 	msg   Message
 	depth int
+	chain *ChainManager
 }
 
-func NewEnv(state *state.StateDB, msg Message, block *types.Block) *VMEnv {
+func NewEnv(state *state.StateDB, chain *ChainManager, msg Message, block *types.Block) *VMEnv {
 	return &VMEnv{
+		chain: chain,
 		state: state,
 		block: block,
 		msg:   msg,
@@ -25,16 +27,21 @@ func NewEnv(state *state.StateDB, msg Message, block *types.Block) *VMEnv {
 
 func (self *VMEnv) Origin() []byte        { return self.msg.From() }
 func (self *VMEnv) BlockNumber() *big.Int { return self.block.Number() }
-func (self *VMEnv) PrevHash() []byte      { return self.block.ParentHash() }
 func (self *VMEnv) Coinbase() []byte      { return self.block.Coinbase() }
 func (self *VMEnv) Time() int64           { return self.block.Time() }
 func (self *VMEnv) Difficulty() *big.Int  { return self.block.Difficulty() }
-func (self *VMEnv) BlockHash() []byte     { return self.block.Hash() }
 func (self *VMEnv) GasLimit() *big.Int    { return self.block.GasLimit() }
 func (self *VMEnv) Value() *big.Int       { return self.msg.Value() }
 func (self *VMEnv) State() *state.StateDB { return self.state }
 func (self *VMEnv) Depth() int            { return self.depth }
 func (self *VMEnv) SetDepth(i int)        { self.depth = i }
+func (self *VMEnv) GetHash(n uint64) []byte {
+	if block := self.chain.GetBlockByNumber(n); block != nil {
+		return block.Hash()
+	}
+
+	return nil
+}
 func (self *VMEnv) AddLog(log state.Log) {
 	self.state.AddLog(log)
 }