hermez-node/db/statedb/txprocessors.go
db/statedb/txprocessors.goRaw
1package statedb
2
3import (
4 "math/big"
5
6 "github.com/hermeznetwork/hermez-node/common"
7 "github.com/iden3/go-iden3-crypto/poseidon"
8 "github.com/iden3/go-merkletree"
9 "github.com/iden3/go-merkletree/db"
10 "github.com/iden3/go-merkletree/db/memory"
11)
12
13// keyidx is used as key in the db to store the current Idx
14var keyidx = []byte("idx")
15
16// ProcessTxs process the given L1Txs & L2Txs applying the needed updates to
17// the StateDB depending on the transaction Type. Returns the common.ZKInputs
18// to generate the SnarkProof later used by the BatchBuilder, and if
19// cmpExitTree is set to true, returns common.ExitTreeLeaf that is later used
20// by the Synchronizer to update the HistoryDB.
21func (s *StateDB) ProcessTxs(cmpExitTree bool, l1usertxs, l1coordinatortxs []*common.L1Tx, l2txs []*common.L2Tx) (*common.ZKInputs, []*common.ExitInfo, error) {
22 var err error
23 var exitTree *merkletree.MerkleTree
24 exits := make(map[common.Idx]common.Account)
25
26 // TBD if ExitTree is only in memory or stored in disk, for the moment
27 // only needed in memory
28 exitTree, err = merkletree.NewMerkleTree(memory.NewMemoryStorage(), s.mt.MaxLevels())
29 if err != nil {
30 return nil, nil, err
31 }
32
33 for _, tx := range l1coordinatortxs {
34 exitIdx, exitAccount, err := s.processL1Tx(exitTree, tx)
35 if err != nil {
36 return nil, nil, err
37 }
38 if exitIdx != nil && cmpExitTree {
39 exits[*exitIdx] = *exitAccount
40 }
41 }
42 for _, tx := range l1usertxs {
43 exitIdx, exitAccount, err := s.processL1Tx(exitTree, tx)
44 if err != nil {
45 return nil, nil, err
46 }
47 if exitIdx != nil && cmpExitTree {
48 exits[*exitIdx] = *exitAccount
49 }
50 }
51 for _, tx := range l2txs {
52 exitIdx, exitAccount, err := s.processL2Tx(exitTree, tx)
53 if err != nil {
54 return nil, nil, err
55 }
56 if exitIdx != nil && cmpExitTree {
57 exits[*exitIdx] = *exitAccount
58 }
59 }
60
61 if !cmpExitTree {
62 return nil, nil, nil
63 }
64
65 // once all txs processed (exitTree root frozen), for each leaf
66 // generate common.ExitInfo data
67 var exitInfos []*common.ExitInfo
68 for exitIdx, exitAccount := range exits {
69 // 0. generate MerkleProof
70 p, err := exitTree.GenerateCircomVerifierProof(exitIdx.BigInt(), nil)
71 if err != nil {
72 return nil, nil, err
73 }
74 // 1. compute nullifier
75 exitAccStateValue, err := exitAccount.HashValue()
76 if err != nil {
77 return nil, nil, err
78 }
79 nullifier, err := poseidon.Hash([]*big.Int{
80 exitAccStateValue,
81 big.NewInt(int64(s.currentBatch)),
82 exitTree.Root().BigInt(),
83 })
84 if err != nil {
85 return nil, nil, err
86 }
87 // 2. generate common.ExitInfo
88 ei := &common.ExitInfo{
89 AccountIdx: exitIdx,
90 MerkleProof: p,
91 Nullifier: nullifier,
92 Balance: exitAccount.Balance,
93 }
94 exitInfos = append(exitInfos, ei)
95 }
96
97 // return exitInfos, so Synchronizer will be able to store it into
98 // HistoryDB for the concrete BatchNum
99 return nil, exitInfos, nil
100}
101
102// processL1Tx process the given L1Tx applying the needed updates to the
103// StateDB depending on the transaction Type.
104func (s *StateDB) processL1Tx(exitTree *merkletree.MerkleTree, tx *common.L1Tx) (*common.Idx, *common.Account, error) {
105 switch tx.Type {
106 case common.TxTypeForceTransfer, common.TxTypeTransfer:
107 // go to the MT account of sender and receiver, and update balance
108 // & nonce
109 err := s.applyTransfer(tx.Tx())
110 if err != nil {
111 return nil, nil, err
112 }
113 case common.TxTypeCreateAccountDeposit:
114 // add new account to the MT, update balance of the MT account
115 err := s.applyCreateAccount(tx)
116 if err != nil {
117 return nil, nil, err
118 }
119 case common.TxTypeDeposit:
120 // update balance of the MT account
121 err := s.applyDeposit(tx, false)
122 if err != nil {
123 return nil, nil, err
124 }
125 case common.TxTypeDepositTransfer:
126 // update balance in MT account, update balance & nonce of sender
127 // & receiver
128 err := s.applyDeposit(tx, true)
129 if err != nil {
130 return nil, nil, err
131 }
132 case common.TxTypeCreateAccountDepositTransfer:
133 // add new account to the merkletree, update balance in MT account,
134 // update balance & nonce of sender & receiver
135 err := s.applyCreateAccount(tx)
136 if err != nil {
137 return nil, nil, err
138 }
139 err = s.applyTransfer(tx.Tx())
140 if err != nil {
141 return nil, nil, err
142 }
143 case common.TxTypeExit:
144 // execute exit flow
145 exitAccount, err := s.applyExit(exitTree, tx.Tx())
146 if err != nil {
147 return nil, nil, err
148 }
149 return &tx.FromIdx, exitAccount, nil
150 default:
151 }
152
153 return nil, nil, nil
154}
155
156// processL2Tx process the given L2Tx applying the needed updates to
157// the StateDB depending on the transaction Type.
158func (s *StateDB) processL2Tx(exitTree *merkletree.MerkleTree, tx *common.L2Tx) (*common.Idx, *common.Account, error) {
159 switch tx.Type {
160 case common.TxTypeTransfer:
161 // go to the MT account of sender and receiver, and update
162 // balance & nonce
163 err := s.applyTransfer(tx.Tx())
164 if err != nil {
165 return nil, nil, err
166 }
167 case common.TxTypeExit:
168 // execute exit flow
169 exitAccount, err := s.applyExit(exitTree, tx.Tx())
170 if err != nil {
171 return nil, nil, err
172 }
173 return &tx.FromIdx, exitAccount, nil
174 default:
175 }
176 return nil, nil, nil
177}
178
179// applyCreateAccount creates a new account in the account of the depositer, it
180// stores the deposit value
181func (s *StateDB) applyCreateAccount(tx *common.L1Tx) error {
182 account := &common.Account{
183 TokenID: tx.TokenID,
184 Nonce: 0,
185 Balance: tx.LoadAmount,
186 PublicKey: tx.FromBJJ,
187 EthAddr: tx.FromEthAddr,
188 }
189
190 _, err := s.CreateAccount(common.Idx(s.idx+1), account)
191 if err != nil {
192 return err
193 }
194
195 s.idx = s.idx + 1
196 return s.setIdx(s.idx)
197}
198
199// applyDeposit updates the balance in the account of the depositer, if
200// andTransfer parameter is set to true, the method will also apply the
201// Transfer of the L1Tx/DepositTransfer
202func (s *StateDB) applyDeposit(tx *common.L1Tx, transfer bool) error {
203 // deposit the tx.LoadAmount into the sender account
204 accSender, err := s.GetAccount(tx.FromIdx)
205 if err != nil {
206 return err
207 }
208 accSender.Balance = new(big.Int).Add(accSender.Balance, tx.LoadAmount)
209
210 // in case that the tx is a L1Tx>DepositTransfer
211 if transfer {
212 accReceiver, err := s.GetAccount(tx.ToIdx)
213 if err != nil {
214 return err
215 }
216 // subtract amount to the sender
217 accSender.Balance = new(big.Int).Sub(accSender.Balance, tx.Amount)
218 // add amount to the receiver
219 accReceiver.Balance = new(big.Int).Add(accReceiver.Balance, tx.Amount)
220 // update receiver account in localStateDB
221 _, err = s.UpdateAccount(tx.ToIdx, accReceiver)
222 if err != nil {
223 return err
224 }
225 }
226 // update sender account in localStateDB
227 _, err = s.UpdateAccount(tx.FromIdx, accSender)
228 if err != nil {
229 return err
230 }
231 return nil
232}
233
234// applyTransfer updates the balance & nonce in the account of the sender, and
235// the balance in the account of the receiver
236func (s *StateDB) applyTransfer(tx *common.Tx) error {
237 // get sender and receiver accounts from localStateDB
238 accSender, err := s.GetAccount(tx.FromIdx)
239 if err != nil {
240 return err
241 }
242 accReceiver, err := s.GetAccount(tx.ToIdx)
243 if err != nil {
244 return err
245 }
246
247 // increment nonce
248 accSender.Nonce++
249
250 // subtract amount to the sender
251 accSender.Balance = new(big.Int).Sub(accSender.Balance, tx.Amount)
252 // add amount to the receiver
253 accReceiver.Balance = new(big.Int).Add(accReceiver.Balance, tx.Amount)
254
255 // update receiver account in localStateDB
256 _, err = s.UpdateAccount(tx.ToIdx, accReceiver)
257 if err != nil {
258 return err
259 }
260 // update sender account in localStateDB
261 _, err = s.UpdateAccount(tx.FromIdx, accSender)
262 if err != nil {
263 return err
264 }
265
266 return nil
267}
268
269func (s *StateDB) applyExit(exitTree *merkletree.MerkleTree, tx *common.Tx) (*common.Account, error) {
270 // 0. subtract tx.Amount from current Account in StateMT
271 // add the tx.Amount into the Account (tx.FromIdx) in the ExitMT
272 acc, err := s.GetAccount(tx.FromIdx)
273 if err != nil {
274 return nil, err
275 }
276 acc.Balance = new(big.Int).Sub(acc.Balance, tx.Amount)
277 _, err = s.UpdateAccount(tx.FromIdx, acc)
278 if err != nil {
279 return nil, err
280 }
281
282 exitAccount, err := getAccountInTreeDB(exitTree.DB(), tx.FromIdx)
283 if err == db.ErrNotFound {
284 // 1a. if idx does not exist in exitTree:
285 // add new leaf 'ExitTreeLeaf', where ExitTreeLeaf.Balance = exitAmount (exitAmount=tx.Amount)
286 exitAccount := &common.Account{
287 TokenID: acc.TokenID,
288 Nonce: common.Nonce(1),
289 Balance: tx.Amount,
290 PublicKey: acc.PublicKey,
291 EthAddr: acc.EthAddr,
292 }
293 _, err = createAccountInTreeDB(exitTree.DB(), exitTree, tx.FromIdx, exitAccount)
294 return exitAccount, err
295 } else if err != nil {
296 return exitAccount, err
297 }
298
299 // 1b. if idx already exist in exitTree:
300 // update account, where account.Balance += exitAmount
301 exitAccount.Balance = new(big.Int).Add(exitAccount.Balance, tx.Amount)
302 _, err = updateAccountInTreeDB(exitTree.DB(), exitTree, tx.FromIdx, exitAccount)
303 return exitAccount, err
304}
305
306// getIdx returns the stored Idx from the localStateDB, which is the last Idx
307// used for an Account in the localStateDB.
308func (s *StateDB) getIdx() (common.Idx, error) {
309 idxBytes, err := s.DB().Get(keyidx)
310 if err == db.ErrNotFound {
311 return 0, nil
312 }
313 if err != nil {
314 return 0, err
315 }
316 return common.IdxFromBytes(idxBytes[:4])
317}
318
319// setIdx stores Idx in the localStateDB
320func (s *StateDB) setIdx(idx common.Idx) error {
321 tx, err := s.DB().NewTx()
322 if err != nil {
323 return err
324 }
325 tx.Put(keyidx, idx.Bytes())
326 if err := tx.Commit(); err != nil {
327 return err
328 }
329 return nil
330}