-
Notifications
You must be signed in to change notification settings - Fork 644
/
builder.go
410 lines (352 loc) · 10.3 KB
/
builder.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
// Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
// See the file LICENSE for licensing terms.
package c
import (
"errors"
"math/big"
"github.com/ava-labs/coreth/plugin/evm"
"github.com/ava-labs/avalanchego/ids"
"github.com/ava-labs/avalanchego/utils"
"github.com/ava-labs/avalanchego/utils/math"
"github.com/ava-labs/avalanchego/utils/set"
"github.com/ava-labs/avalanchego/vms/components/avax"
"github.com/ava-labs/avalanchego/vms/secp256k1fx"
"github.com/ava-labs/avalanchego/wallet/subnet/primary/common"
stdcontext "context"
ethcommon "github.com/ethereum/go-ethereum/common"
)
const avaxConversionRateInt = 1_000_000_000
var (
_ Builder = (*builder)(nil)
errInsufficientFunds = errors.New("insufficient funds")
// avaxConversionRate is the conversion rate between the smallest
// denomination on the X-Chain and P-chain, 1 nAVAX, and the smallest
// denomination on the C-Chain 1 wei. Where 1 nAVAX = 1 gWei.
//
// This is only required for AVAX because the denomination of 1 AVAX is 9
// decimal places on the X and P chains, but is 18 decimal places within the
// EVM.
avaxConversionRate = big.NewInt(avaxConversionRateInt)
)
// Builder provides a convenient interface for building unsigned C-chain
// transactions.
type Builder interface {
// GetBalance calculates the amount of AVAX that this builder has control
// over.
GetBalance(
options ...common.Option,
) (*big.Int, error)
// GetImportableBalance calculates the amount of AVAX that this builder
// could import from the provided chain.
//
// - [chainID] specifies the chain the funds are from.
GetImportableBalance(
chainID ids.ID,
options ...common.Option,
) (uint64, error)
// NewImportTx creates an import transaction that attempts to consume all
// the available UTXOs and import the funds to [to].
//
// - [chainID] specifies the chain to be importing funds from.
// - [to] specifies where to send the imported funds to.
// - [baseFee] specifies the fee price willing to be paid by this tx.
NewImportTx(
chainID ids.ID,
to ethcommon.Address,
baseFee *big.Int,
options ...common.Option,
) (*evm.UnsignedImportTx, error)
// NewExportTx creates an export transaction that attempts to send all the
// provided [outputs] to the requested [chainID].
//
// - [chainID] specifies the chain to be exporting the funds to.
// - [outputs] specifies the outputs to send to the [chainID].
// - [baseFee] specifies the fee price willing to be paid by this tx.
NewExportTx(
chainID ids.ID,
outputs []*secp256k1fx.TransferOutput,
baseFee *big.Int,
options ...common.Option,
) (*evm.UnsignedExportTx, error)
}
// BuilderBackend specifies the required information needed to build unsigned
// C-chain transactions.
type BuilderBackend interface {
Context
UTXOs(ctx stdcontext.Context, sourceChainID ids.ID) ([]*avax.UTXO, error)
Balance(ctx stdcontext.Context, addr ethcommon.Address) (*big.Int, error)
Nonce(ctx stdcontext.Context, addr ethcommon.Address) (uint64, error)
}
type builder struct {
avaxAddrs set.Set[ids.ShortID]
ethAddrs set.Set[ethcommon.Address]
backend BuilderBackend
}
// NewBuilder returns a new transaction builder.
//
// - [avaxAddrs] is the set of addresses in the AVAX format that the builder
// assumes can be used when signing the transactions in the future.
// - [ethAddrs] is the set of addresses in the Eth format that the builder
// assumes can be used when signing the transactions in the future.
// - [backend] provides the required access to the chain's context and state
// to build out the transactions.
func NewBuilder(
avaxAddrs set.Set[ids.ShortID],
ethAddrs set.Set[ethcommon.Address],
backend BuilderBackend,
) Builder {
return &builder{
avaxAddrs: avaxAddrs,
ethAddrs: ethAddrs,
backend: backend,
}
}
func (b *builder) GetBalance(
options ...common.Option,
) (*big.Int, error) {
var (
ops = common.NewOptions(options)
ctx = ops.Context()
addrs = ops.EthAddresses(b.ethAddrs)
totalBalance = new(big.Int)
)
for addr := range addrs {
balance, err := b.backend.Balance(ctx, addr)
if err != nil {
return nil, err
}
totalBalance.Add(totalBalance, balance)
}
return totalBalance, nil
}
func (b *builder) GetImportableBalance(
chainID ids.ID,
options ...common.Option,
) (uint64, error) {
ops := common.NewOptions(options)
utxos, err := b.backend.UTXOs(ops.Context(), chainID)
if err != nil {
return 0, err
}
var (
addrs = ops.Addresses(b.avaxAddrs)
minIssuanceTime = ops.MinIssuanceTime()
avaxAssetID = b.backend.AVAXAssetID()
balance uint64
)
for _, utxo := range utxos {
amount, _, ok := getSpendableAmount(utxo, addrs, minIssuanceTime, avaxAssetID)
if !ok {
continue
}
newBalance, err := math.Add64(balance, amount)
if err != nil {
return 0, err
}
balance = newBalance
}
return balance, nil
}
func (b *builder) NewImportTx(
chainID ids.ID,
to ethcommon.Address,
baseFee *big.Int,
options ...common.Option,
) (*evm.UnsignedImportTx, error) {
ops := common.NewOptions(options)
utxos, err := b.backend.UTXOs(ops.Context(), chainID)
if err != nil {
return nil, err
}
var (
addrs = ops.Addresses(b.avaxAddrs)
minIssuanceTime = ops.MinIssuanceTime()
avaxAssetID = b.backend.AVAXAssetID()
importedInputs = make([]*avax.TransferableInput, 0, len(utxos))
importedAmount uint64
)
for _, utxo := range utxos {
amount, inputSigIndices, ok := getSpendableAmount(utxo, addrs, minIssuanceTime, avaxAssetID)
if !ok {
continue
}
importedInputs = append(importedInputs, &avax.TransferableInput{
UTXOID: utxo.UTXOID,
Asset: utxo.Asset,
FxID: secp256k1fx.ID,
In: &secp256k1fx.TransferInput{
Amt: amount,
Input: secp256k1fx.Input{
SigIndices: inputSigIndices,
},
},
})
newImportedAmount, err := math.Add64(importedAmount, amount)
if err != nil {
return nil, err
}
importedAmount = newImportedAmount
}
utils.Sort(importedInputs)
tx := &evm.UnsignedImportTx{
NetworkID: b.backend.NetworkID(),
BlockchainID: b.backend.BlockchainID(),
SourceChain: chainID,
ImportedInputs: importedInputs,
}
// We must initialize the bytes of the tx to calculate the initial cost
wrappedTx := &evm.Tx{UnsignedAtomicTx: tx}
if err := wrappedTx.Sign(evm.Codec, nil); err != nil {
return nil, err
}
gasUsedWithoutOutput, err := tx.GasUsed(true /*=IsApricotPhase5*/)
if err != nil {
return nil, err
}
gasUsedWithOutput := gasUsedWithoutOutput + evm.EVMOutputGas
txFee, err := evm.CalculateDynamicFee(gasUsedWithOutput, baseFee)
if err != nil {
return nil, err
}
if importedAmount <= txFee {
return nil, errInsufficientFunds
}
tx.Outs = []evm.EVMOutput{{
Address: to,
Amount: importedAmount - txFee,
AssetID: avaxAssetID,
}}
return tx, nil
}
func (b *builder) NewExportTx(
chainID ids.ID,
outputs []*secp256k1fx.TransferOutput,
baseFee *big.Int,
options ...common.Option,
) (*evm.UnsignedExportTx, error) {
var (
avaxAssetID = b.backend.AVAXAssetID()
exportedOutputs = make([]*avax.TransferableOutput, len(outputs))
exportedAmount uint64
)
for i, output := range outputs {
exportedOutputs[i] = &avax.TransferableOutput{
Asset: avax.Asset{ID: avaxAssetID},
FxID: secp256k1fx.ID,
Out: output,
}
newExportedAmount, err := math.Add64(exportedAmount, output.Amt)
if err != nil {
return nil, err
}
exportedAmount = newExportedAmount
}
avax.SortTransferableOutputs(exportedOutputs, evm.Codec)
tx := &evm.UnsignedExportTx{
NetworkID: b.backend.NetworkID(),
BlockchainID: b.backend.BlockchainID(),
DestinationChain: chainID,
ExportedOutputs: exportedOutputs,
}
// We must initialize the bytes of the tx to calculate the initial cost
wrappedTx := &evm.Tx{UnsignedAtomicTx: tx}
if err := wrappedTx.Sign(evm.Codec, nil); err != nil {
return nil, err
}
cost, err := tx.GasUsed(true /*=IsApricotPhase5*/)
if err != nil {
return nil, err
}
initialFee, err := evm.CalculateDynamicFee(cost, baseFee)
if err != nil {
return nil, err
}
amountToConsume, err := math.Add64(exportedAmount, initialFee)
if err != nil {
return nil, err
}
var (
ops = common.NewOptions(options)
ctx = ops.Context()
addrs = ops.EthAddresses(b.ethAddrs)
inputs = make([]evm.EVMInput, 0, addrs.Len())
)
for addr := range addrs {
if amountToConsume == 0 {
break
}
prevFee, err := evm.CalculateDynamicFee(cost, baseFee)
if err != nil {
return nil, err
}
newCost := cost + evm.EVMInputGas
newFee, err := evm.CalculateDynamicFee(newCost, baseFee)
if err != nil {
return nil, err
}
additionalFee := newFee - prevFee
balance, err := b.backend.Balance(ctx, addr)
if err != nil {
return nil, err
}
// Since the asset is AVAX, we divide by the avaxConversionRate to
// convert back to the correct denomination of AVAX that can be
// exported.
avaxBalance := new(big.Int).Div(balance, avaxConversionRate).Uint64()
// If the balance for [addr] is insufficient to cover the additional
// cost of adding an input to the transaction, skip adding the input
// altogether.
if avaxBalance <= additionalFee {
continue
}
// Update the cost for the next iteration
cost = newCost
amountToConsume, err = math.Add64(amountToConsume, additionalFee)
if err != nil {
return nil, err
}
nonce, err := b.backend.Nonce(ctx, addr)
if err != nil {
return nil, err
}
inputAmount := min(amountToConsume, avaxBalance)
inputs = append(inputs, evm.EVMInput{
Address: addr,
Amount: inputAmount,
AssetID: avaxAssetID,
Nonce: nonce,
})
amountToConsume -= inputAmount
}
if amountToConsume > 0 {
return nil, errInsufficientFunds
}
utils.Sort(inputs)
tx.Ins = inputs
snowCtx, err := newSnowContext(b.backend)
if err != nil {
return nil, err
}
for _, out := range tx.ExportedOutputs {
out.InitCtx(snowCtx)
}
return tx, nil
}
func getSpendableAmount(
utxo *avax.UTXO,
addrs set.Set[ids.ShortID],
minIssuanceTime uint64,
avaxAssetID ids.ID,
) (uint64, []uint32, bool) {
if utxo.Asset.ID != avaxAssetID {
// Only AVAX can be imported
return 0, nil, false
}
out, ok := utxo.Out.(*secp256k1fx.TransferOutput)
if !ok {
// Can't import an unknown transfer output type
return 0, nil, false
}
inputSigIndices, ok := common.MatchOwners(&out.OutputOwners, addrs, minIssuanceTime)
return out.Amt, inputSigIndices, ok
}