forked from cerc-io/plugeth
156 lines
3.3 KiB
Go
156 lines
3.3 KiB
Go
package ethchain
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import (
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"github.com/ethereum/eth-go/ethutil"
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"math/big"
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)
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// States within the ethereum protocol are used to store anything
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// within the merkle trie. States take care of caching and storing
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// nested states. It's the general query interface to retrieve:
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// * Contracts
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// * Accounts
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type State struct {
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// The trie for this structure
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trie *ethutil.Trie
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// Nested states
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states map[string]*State
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}
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// Create a new state from a given trie
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func NewState(trie *ethutil.Trie) *State {
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return &State{trie: trie, states: make(map[string]*State)}
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}
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// Resets the trie and all siblings
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func (s *State) Reset() {
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s.trie.Undo()
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// Reset all nested states
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for _, state := range s.states {
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state.Reset()
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}
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}
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// Syncs the trie and all siblings
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func (s *State) Sync() {
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s.trie.Sync()
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// Sync all nested states
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for _, state := range s.states {
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state.Sync()
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}
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}
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// Purges the current trie.
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func (s *State) Purge() int {
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return s.trie.NewIterator().Purge()
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}
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func (s *State) GetContract(addr []byte) *Contract {
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data := s.trie.Get(string(addr))
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if data == "" {
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return nil
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}
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// Whet get contract is called the retrieved value might
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// be an account. The StateManager uses this to check
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// to see if the address a tx was sent to is a contract
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// or an account
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value := ethutil.NewValueFromBytes([]byte(data))
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if value.Len() == 2 {
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return nil
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}
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// build contract
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contract := &Contract{}
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contract.RlpDecode([]byte(data))
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// Check if there's a cached state for this contract
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cachedState := s.states[string(addr)]
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if cachedState != nil {
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contract.state = cachedState
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} else {
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// If it isn't cached, cache the state
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s.states[string(addr)] = contract.state
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}
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return contract
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}
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func (s *State) UpdateContract(addr []byte, contract *Contract) {
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s.trie.Update(string(addr), string(contract.RlpEncode()))
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}
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func Compile(code []string) (script []string) {
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script = make([]string, len(code))
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for i, val := range code {
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instr, _ := ethutil.CompileInstr(val)
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script[i] = string(instr)
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}
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return
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}
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func (s *State) GetAccount(addr []byte) (account *Account) {
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data := s.trie.Get(string(addr))
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if data == "" {
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account = NewAccount(big.NewInt(0))
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} else {
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account = NewAccountFromData([]byte(data))
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}
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return
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}
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func (s *State) UpdateAccount(addr []byte, account *Account) {
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s.trie.Update(string(addr), string(account.RlpEncode()))
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}
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func (s *State) Cmp(other *State) bool {
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return s.trie.Cmp(other.trie)
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}
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func (s *State) Copy() *State {
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return NewState(s.trie.Copy())
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}
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type ObjType byte
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const (
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NilTy ObjType = iota
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AccountTy
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ContractTy
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UnknownTy
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)
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// Returns the object stored at key and the type stored at key
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// Returns nil if nothing is stored
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func (s *State) Get(key []byte) (*ethutil.Value, ObjType) {
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// Fetch data from the trie
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data := s.trie.Get(string(key))
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// Returns the nil type, indicating nothing could be retrieved.
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// Anything using this function should check for this ret val
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if data == "" {
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return nil, NilTy
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}
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var typ ObjType
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val := ethutil.NewValueFromBytes([]byte(data))
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// Check the length of the retrieved value.
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// Len 2 = Account
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// Len 3 = Contract
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// Other = invalid for now. If other types emerge, add them here
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if val.Len() == 2 {
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typ = AccountTy
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} else if val.Len() == 3 {
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typ = ContractTy
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} else {
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typ = UnknownTy
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}
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return val, typ
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}
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