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
|
const EthQuery = require('ethjs-query')
const {
hexToBn,
BnMultiplyByFraction,
bnToHex,
} = require('../../lib/util')
const { addHexPrefix } = require('ethereumjs-util')
const SIMPLE_GAS_COST = '0x5208' // Hex for 21000, cost of a simple send.
import { TRANSACTION_NO_CONTRACT_ERROR_KEY } from '../../../../ui/app/constants/error-keys'
/**
tx-gas-utils are gas utility methods for Transaction manager
its passed ethquery
and used to do things like calculate gas of a tx.
@param {Object} provider - A network provider.
*/
class TxGasUtil {
constructor (provider) {
this.query = new EthQuery(provider)
}
/**
@param txMeta {Object} - the txMeta object
@returns {object} the txMeta object with the gas written to the txParams
*/
async analyzeGasUsage (txMeta) {
const block = await this.query.getBlockByNumber('latest', false)
let estimatedGasHex
try {
estimatedGasHex = await this.estimateTxGas(txMeta, block.gasLimit)
} catch (err) {
txMeta.simulationFails = {
reason: err.message,
errorKey: err.errorKey,
}
return txMeta
}
this.setTxGas(txMeta, block.gasLimit, estimatedGasHex)
return txMeta
}
/**
Estimates the tx's gas usage
@param txMeta {Object} - the txMeta object
@param blockGasLimitHex {string} - hex string of the block's gas limit
@returns {string} the estimated gas limit as a hex string
*/
async estimateTxGas (txMeta, blockGasLimitHex) {
const txParams = txMeta.txParams
// check if gasLimit is already specified
txMeta.gasLimitSpecified = Boolean(txParams.gas)
// if it is, use that value
if (txMeta.gasLimitSpecified) {
return txParams.gas
}
const recipient = txParams.to
const hasRecipient = Boolean(recipient)
if (hasRecipient) {
const code = await this.query.getCode(recipient)
// If there's data in the params, but there's no code, it's not a valid contract
// For no code, Infura will return '0x', and ganache-core v2.2.1 will return '0x0'
if (txParams.data && (!code || code === '0x' || code === '0x0')) {
const err = new Error()
err.errorKey = TRANSACTION_NO_CONTRACT_ERROR_KEY
throw err
} else if (!code) {
txParams.gas = SIMPLE_GAS_COST // For a standard ETH send, gas is 21k max
txMeta.simpleSend = true // Prevents buffer addition
return SIMPLE_GAS_COST
}
}
// if not, fall back to block gasLimit
const blockGasLimitBN = hexToBn(blockGasLimitHex)
const saferGasLimitBN = BnMultiplyByFraction(blockGasLimitBN, 19, 20)
txParams.gas = bnToHex(saferGasLimitBN)
// run tx
return await this.query.estimateGas(txParams)
}
/**
Writes the gas on the txParams in the txMeta
@param txMeta {Object} - the txMeta object to write to
@param blockGasLimitHex {string} - the block gas limit hex
@param estimatedGasHex {string} - the estimated gas hex
*/
setTxGas (txMeta, blockGasLimitHex, estimatedGasHex) {
txMeta.estimatedGas = addHexPrefix(estimatedGasHex)
const txParams = txMeta.txParams
// if gasLimit was specified and doesnt OOG,
// use original specified amount
if (txMeta.gasLimitSpecified || txMeta.simpleSend) {
txMeta.estimatedGas = txParams.gas
return
}
// if gasLimit not originally specified,
// try adding an additional gas buffer to our estimation for safety
const recommendedGasHex = this.addGasBuffer(txMeta.estimatedGas, blockGasLimitHex)
txParams.gas = recommendedGasHex
return
}
/**
Adds a gas buffer with out exceeding the block gas limit
@param initialGasLimitHex {string} - the initial gas limit to add the buffer too
@param blockGasLimitHex {string} - the block gas limit
@returns {string} the buffered gas limit as a hex string
*/
addGasBuffer (initialGasLimitHex, blockGasLimitHex) {
const initialGasLimitBn = hexToBn(initialGasLimitHex)
const blockGasLimitBn = hexToBn(blockGasLimitHex)
const upperGasLimitBn = blockGasLimitBn.muln(0.9)
const bufferedGasLimitBn = initialGasLimitBn.muln(1.5)
// if initialGasLimit is above blockGasLimit, dont modify it
if (initialGasLimitBn.gt(upperGasLimitBn)) return bnToHex(initialGasLimitBn)
// if bufferedGasLimit is below blockGasLimit, use bufferedGasLimit
if (bufferedGasLimitBn.lt(upperGasLimitBn)) return bnToHex(bufferedGasLimitBn)
// otherwise use blockGasLimit
return bnToHex(upperGasLimitBn)
}
}
module.exports = TxGasUtil
|
