direct_by_leaf/state_object.go

@@ -340,9 +340,36 @@ func (s *stateObject) Nonce() uint64 {
 	return s.data.Nonce
 }
 
-// Never called, but must be present to allow stateObject to be used
+// Value is never called, but must be present to allow stateObject to be used
 // as a vm.Account interface that also satisfies the vm.ContractRef
 // interface. Interfaces are awesome.
 func (s *stateObject) Value() *big.Int {
 	panic("Value on stateObject should never be called")
 }
+
+// finalise moves all dirty storage slots into the pending area to be hashed or
+// committed later. It is invoked at the end of every transaction.
+func (s *stateObject) finalise(prefetch bool) {
+	slotsToPrefetch := make([][]byte, 0, len(s.dirtyStorage))
+	for key, value := range s.dirtyStorage {
+		s.pendingStorage[key] = value
+		if value != s.originStorage[key] {
+			slotsToPrefetch = append(slotsToPrefetch, common.CopyBytes(key[:])) // Copy needed for closure
+		}
+	}
+	if len(s.dirtyStorage) > 0 {
+		s.dirtyStorage = make(Storage)
+	}
+}
+
+func (s *stateObject) deepCopy(db *StateDB) *stateObject {
+	stateObject := newObject(db, s.address, s.data, s.blockHash)
+	stateObject.code = s.code
+	stateObject.dirtyStorage = s.dirtyStorage.Copy()
+	stateObject.originStorage = s.originStorage.Copy()
+	stateObject.pendingStorage = s.pendingStorage.Copy()
+	stateObject.suicided = s.suicided
+	stateObject.dirtyCode = s.dirtyCode
+	stateObject.deleted = s.deleted
+	return stateObject
+}

direct_by_leaf/statedb.go

@@ -54,6 +54,7 @@ type StateDB struct {
 	stateObjects         map[common.Address]*stateObject
 	stateObjectsPending  map[common.Address]struct{} // State objects finalized but not yet written to the trie
 	stateObjectsDirty    map[common.Address]struct{} // State objects modified in the current execution
+	stateObjectsDestruct map[common.Address]struct{} // State objects destructed in the block
 
 	// DB error.
 	// State objects are used by the consensus core and VM which are
@@ -97,6 +98,7 @@ func New(blockHash common.Hash, db StateDatabase) (*StateDB, error) {
 		stateObjects:         make(map[common.Address]*stateObject),
 		stateObjectsPending:  make(map[common.Address]struct{}),
 		stateObjectsDirty:    make(map[common.Address]struct{}),
+		stateObjectsDestruct: make(map[common.Address]struct{}),
 		logs:                 make(map[common.Hash][]*types.Log),
 		preimages:            make(map[common.Hash][]byte),
 		journal:              newJournal(),
@@ -282,6 +284,7 @@ func (s *StateDB) SetState(addr common.Address, key, value common.Hash) {
 // SetStorage replaces the entire storage for the specified account with given
 // storage. This function should only be used for debugging.
 func (s *StateDB) SetStorage(addr common.Address, storage map[common.Hash]common.Hash) {
+	s.stateObjectsDestruct[addr] = struct{}{}
 	stateObject := s.getOrNewStateObject(addr)
 	if stateObject != nil {
 		stateObject.SetStorage(storage)
@@ -399,11 +402,19 @@ func (s *StateDB) getOrNewStateObject(addr common.Address) *stateObject {
 // the given address, it is overwritten and returned as the second return value.
 func (s *StateDB) createObject(addr common.Address) (newobj, prev *stateObject) {
 	prev = s.getDeletedStateObject(addr) // Note, prev might have been deleted, we need that!
+
+	var prevdestruct bool
+	if prev != nil {
+		_, prevdestruct = s.stateObjectsDestruct[prev.address]
+		if !prevdestruct {
+			s.stateObjectsDestruct[prev.address] = struct{}{}
+		}
+	}
 	newobj = newObject(s, addr, types.StateAccount{}, s.originBlockHash)
 	if prev == nil {
 		s.journal.append(createObjectChange{account: &addr})
 	} else {
-		s.journal.append(resetObjectChange{prev: prev}) // NOTE: prevdestruct used to be set here from snapshot
+		s.journal.append(resetObjectChange{prev: prev, prevdestruct: prevdestruct}) // NOTE: prevdestruct used to be set here from snapshot
 	}
 	s.setStateObject(newobj)
 	if prev != nil && !prev.deleted {
@@ -541,3 +552,128 @@ func (s *StateDB) AddressInAccessList(addr common.Address) bool {
 func (s *StateDB) SlotInAccessList(addr common.Address, slot common.Hash) (addressPresent bool, slotPresent bool) {
 	return s.accessList.Contains(addr, slot)
 }
+
+// Finalise finalises the state by removing the destructed objects and clears
+// the journal as well as the refunds. Finalise, however, will not push any updates
+// into the tries just yet. Only IntermediateRoot or Commit will do that.
+func (s *StateDB) Finalise(deleteEmptyObjects bool) {
+	for addr := range s.journal.dirties {
+		obj, exist := s.stateObjects[addr]
+		if !exist {
+			// ripeMD is 'touched' at block 1714175, in tx 0x1237f737031e40bcde4a8b7e717b2d15e3ecadfe49bb1bbc71ee9deb09c6fcf2
+			// That tx goes out of gas, and although the notion of 'touched' does not exist there, the
+			// touch-event will still be recorded in the journal. Since ripeMD is a special snowflake,
+			// it will persist in the journal even though the journal is reverted. In this special circumstance,
+			// it may exist in `s.journal.dirties` but not in `s.stateObjects`.
+			// Thus, we can safely ignore it here
+			continue
+		}
+		if obj.suicided || (deleteEmptyObjects && obj.empty()) {
+			obj.deleted = true
+
+			// We need to maintain account deletions explicitly (will remain
+			// set indefinitely).
+			s.stateObjectsDestruct[obj.address] = struct{}{}
+		} else {
+			obj.finalise(true) // Prefetch slots in the background
+		}
+		s.stateObjectsPending[addr] = struct{}{}
+		s.stateObjectsDirty[addr] = struct{}{}
+	}
+
+	// Invalidate journal because reverting across transactions is not allowed.
+	s.clearJournalAndRefund()
+}
+
+// SetTxContext sets the current transaction hash and index which are
+// used when the EVM emits new state logs. It should be invoked before
+// transaction execution.
+func (s *StateDB) SetTxContext(thash common.Hash, ti int) {
+	s.thash = thash
+	s.txIndex = ti
+}
+
+func (s *StateDB) clearJournalAndRefund() {
+	if len(s.journal.entries) > 0 {
+		s.journal = newJournal()
+		s.refund = 0
+	}
+	s.validRevisions = s.validRevisions[:0] // Snapshots can be created without journal entries
+}
+
+// Copy creates a deep, independent copy of the state.
+// Snapshots of the copied state cannot be applied to the copy.
+func (s *StateDB) Copy() *StateDB {
+	// Copy all the basic fields, initialize the memory ones
+	state := &StateDB{
+		db:                   s.db,
+		originBlockHash:      s.originBlockHash,
+		stateObjects:         make(map[common.Address]*stateObject, len(s.journal.dirties)),
+		stateObjectsPending:  make(map[common.Address]struct{}, len(s.stateObjectsPending)),
+		stateObjectsDirty:    make(map[common.Address]struct{}, len(s.journal.dirties)),
+		stateObjectsDestruct: make(map[common.Address]struct{}, len(s.stateObjectsDestruct)),
+		refund:               s.refund,
+		logs:                 make(map[common.Hash][]*types.Log, len(s.logs)),
+		logSize:              s.logSize,
+		preimages:            make(map[common.Hash][]byte, len(s.preimages)),
+		journal:              newJournal(),
+		hasher:               crypto.NewKeccakState(),
+	}
+	// Copy the dirty states, logs, and preimages
+	for addr := range s.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 := s.stateObjects[addr]; exist {
+			// Even though the original object is dirty, we are not copying the journal,
+			// so we need to make sure that any side-effect the journal would have caused
+			// during a commit (or similar op) is already applied to the copy.
+			state.stateObjects[addr] = object.deepCopy(state)
+
+			state.stateObjectsDirty[addr] = struct{}{}   // Mark the copy dirty to force internal (code/state) commits
+			state.stateObjectsPending[addr] = struct{}{} // Mark the copy pending to force external (account) commits
+		}
+	}
+	// 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 s.stateObjectsPending {
+		if _, exist := state.stateObjects[addr]; !exist {
+			state.stateObjects[addr] = s.stateObjects[addr].deepCopy(state)
+		}
+		state.stateObjectsPending[addr] = struct{}{}
+	}
+	for addr := range s.stateObjectsDirty {
+		if _, exist := state.stateObjects[addr]; !exist {
+			state.stateObjects[addr] = s.stateObjects[addr].deepCopy(state)
+		}
+		state.stateObjectsDirty[addr] = struct{}{}
+	}
+	// Deep copy the destruction flag.
+	for addr := range s.stateObjectsDestruct {
+		state.stateObjectsDestruct[addr] = struct{}{}
+	}
+	for hash, logs := range s.logs {
+		cpy := make([]*types.Log, len(logs))
+		for i, l := range logs {
+			cpy[i] = new(types.Log)
+			*cpy[i] = *l
+		}
+		state.logs[hash] = cpy
+	}
+	for hash, preimage := range s.preimages {
+		state.preimages[hash] = preimage
+	}
+	// Do we need to copy the access list and transient storage?
+	// In practice: No. At the start of a transaction, these two lists are empty.
+	// In practice, we only ever copy state _between_ transactions/blocks, never
+	// in the middle of a transaction. However, it doesn't cost us much to copy
+	// empty lists, so we do it anyway to not blow up if we ever decide copy them
+	// in the middle of a transaction.
+	state.accessList = s.accessList.Copy()
+	state.transientStorage = s.transientStorage.Copy()
+
+	return state
+}