tokenbridge/commons/message.js

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const { soliditySha3 } = require('web3-utils')
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function strip0x(input) {
return input.replace(/^0x/, '')
}
/**
* Decodes the datatype byte from the AMB message.
* First (the most significant bit) denotes if the message should be forwarded to the manual lane.
* @param dataType: number datatype of the received AMB message.
* @return {{manualLane: boolean}}
*/
const decodeAMBDataType = dataType => ({
manualLane: (dataType & 128) === 128
})
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function parseAMBMessage(message) {
message = strip0x(message)
const messageId = `0x${message.slice(0, 64)}`
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const sender = `0x${message.slice(64, 104)}`
const executor = `0x${message.slice(104, 144)}`
const dataType = parseInt(message.slice(156, 158), 16)
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return {
sender,
executor,
messageId,
dataType,
decodedDataType: decodeAMBDataType(dataType)
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}
}
const normalizeAMBMessageEvent = e => {
let msgData = e.returnValues.encodedData
if (!e.returnValues.messageId) {
// append tx hash to an old message, where message id was not used
// for old messages, e.messageId is a corresponding transactionHash
msgData = e.transactionHash + msgData.slice(2)
}
return parseAMBMessage(msgData)
}
const ambInformationSignatures = [
'eth_call(address,bytes)',
'eth_call(address,bytes,uint256)',
'eth_call(address,address,uint256,bytes)',
'eth_blockNumber()',
'eth_getBlockByNumber()',
'eth_getBlockByNumber(uint256)',
'eth_getBlockByHash(bytes32)',
'eth_getBalance(address)',
'eth_getBalance(address,uint256)',
'eth_getTransactionCount(address)',
'eth_getTransactionCount(address,uint256)',
'eth_getTransactionByHash(bytes32)',
'eth_getTransactionReceipt(bytes32)',
'eth_getStorageAt(address,bytes32)',
'eth_getStorageAt(address,bytes32,uint256)'
]
const ambInformationSelectors = Object.fromEntries(ambInformationSignatures.map(sig => [soliditySha3(sig), sig]))
const normalizeAMBInfoRequest = e => ({
messageId: e.returnValues.messageId,
sender: e.returnValues.sender,
requestSelector: ambInformationSelectors[e.returnValues.requestSelector] || 'unknown',
data: e.returnValues.data
})
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module.exports = {
strip0x,
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parseAMBMessage,
normalizeAMBMessageEvent,
ambInformationSignatures,
normalizeAMBInfoRequest
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}