Method Copy

core/state/statedb.go:456–501

Copy creates a deep, independent copy of the state. Snapshots of the copied state cannot be applied to the copy.

()

// Copy creates a deep, independent copy of the state.
// Snapshots of the copied state cannot be applied to the copy.
func (self *StateDB) Copy() *StateDB {
	self.lock.Lock()
	defer self.lock.Unlock()

	// Copy all the basic fields, initialize the memory ones
	state := &StateDB{
		db:                self.db,
		trie:              self.db.CopyTrie(self.trie),
		stateObjects:      make(map[common.Address]*stateObject, len(self.journal.dirties)),
		stateObjectsDirty: make(map[common.Address]struct{}, len(self.journal.dirties)),
		refund:            self.refund,
		logs:              make(map[common.Hash][]*types.Log, len(self.logs)),
		logSize:           self.logSize,
		preimages:         make(map[common.Hash][]byte),
		journal:           newJournal(),
	}
	// Copy the dirty states, logs, and preimages
	for addr := range self.journal.dirties {
		// As documented [here](https://github.com/ethereum/go-ethereum/pull/16485#issuecomment-380438527),
		// and in the Finalise-method, there is a case where an object is in the journal but not
		// in the stateObjects: OOG after touch on ripeMD prior to Byzantium. Thus, we need to check for
		// nil
		if object, exist := self.stateObjects[addr]; exist {
			state.stateObjects[addr] = object.deepCopy(state)
			state.stateObjectsDirty[addr] = struct{}{}
		}
	}
	// Above, we don't copy the actual journal. This means that if the copy is copied, the
	// loop above will be a no-op, since the copy's journal is empty.
	// Thus, here we iterate over stateObjects, to enable copies of copies
	for addr := range self.stateObjectsDirty {
		if _, exist := state.stateObjects[addr]; !exist {
			state.stateObjects[addr] = self.stateObjects[addr].deepCopy(state)
			state.stateObjectsDirty[addr] = struct{}{}
		}
	}

	for hash, logs := range self.logs {
		state.logs[hash] = make([]*types.Log, len(logs))
		copy(state.logs[hash], logs)
	}
	for hash, preimage := range self.preimages {
		state.preimages[hash] = preimage
	}
	return state
}

// Snapshot returns an identifier for the current revision of the state.
func (self *StateDB) Snapshot() int {