mirror of
https://github.com/kremalicious/metamask-extension.git
synced 2024-12-23 09:52:26 +01:00
110 lines
3.4 KiB
JavaScript
110 lines
3.4 KiB
JavaScript
const ethUtil = require('ethereumjs-util')
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const assert = require('assert')
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const BN = require('bn.js')
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const {
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ENVIRONMENT_TYPE_POPUP,
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ENVIRONMENT_TYPE_NOTIFICATION,
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ENVIRONMENT_TYPE_FULLSCREEN,
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} = require('./enums')
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/**
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* Generates an example stack trace
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*
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* @returns {string} A stack trace
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*
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*/
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function getStack () {
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const stack = new Error('Stack trace generator - not an error').stack
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return stack
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}
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/**
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* Used to determine the window type through which the app is being viewed.
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* - 'popup' refers to the extension opened through the browser app icon (in top right corner in chrome and firefox)
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* - 'responsive' refers to the main browser window
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* - 'notification' refers to the popup that appears in its own window when taking action outside of metamask
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*
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* @returns {string} A single word label that represents the type of window through which the app is being viewed
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*
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*/
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const getEnvironmentType = (url = window.location.href) => {
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if (url.match(/popup.html(?:#.*)*$/)) {
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return ENVIRONMENT_TYPE_POPUP
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} else if (url.match(/home.html(?:\?.+)*$/) || url.match(/home.html(?:#.*)*$/)) {
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return ENVIRONMENT_TYPE_FULLSCREEN
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} else {
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return ENVIRONMENT_TYPE_NOTIFICATION
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}
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}
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/**
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* Checks whether a given balance of ETH, represented as a hex string, is sufficient to pay a value plus a gas fee
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*
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* @param {object} txParams Contains data about a transaction
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* @param {string} txParams.gas The gas for a transaction
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* @param {string} txParams.gasPrice The price per gas for the transaction
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* @param {string} txParams.value The value of ETH to send
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* @param {string} hexBalance A balance of ETH represented as a hex string
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* @returns {boolean} Whether the balance is greater than or equal to the value plus the value of gas times gasPrice
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*
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*/
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function sufficientBalance (txParams, hexBalance) {
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// validate hexBalance is a hex string
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assert.equal(typeof hexBalance, 'string', 'sufficientBalance - hexBalance is not a hex string')
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assert.equal(hexBalance.slice(0, 2), '0x', 'sufficientBalance - hexBalance is not a hex string')
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const balance = hexToBn(hexBalance)
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const value = hexToBn(txParams.value)
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const gasLimit = hexToBn(txParams.gas)
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const gasPrice = hexToBn(txParams.gasPrice)
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const maxCost = value.add(gasLimit.mul(gasPrice))
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return balance.gte(maxCost)
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}
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/**
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* Converts a BN object to a hex string with a '0x' prefix
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*
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* @param {BN} inputBn The BN to convert to a hex string
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* @returns {string} A '0x' prefixed hex string
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*
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*/
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function bnToHex (inputBn) {
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return ethUtil.addHexPrefix(inputBn.toString(16))
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}
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/**
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* Converts a hex string to a BN object
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*
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* @param {string} inputHex A number represented as a hex string
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* @returns {Object} A BN object
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*
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*/
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function hexToBn (inputHex) {
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return new BN(ethUtil.stripHexPrefix(inputHex), 16)
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}
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/**
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* Used to multiply a BN by a fraction
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*
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* @param {BN} targetBN The number to multiply by a fraction
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* @param {number|string} numerator The numerator of the fraction multiplier
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* @param {number|string} denominator The denominator of the fraction multiplier
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* @returns {BN} The product of the multiplication
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*
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*/
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function BnMultiplyByFraction (targetBN, numerator, denominator) {
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const numBN = new BN(numerator)
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const denomBN = new BN(denominator)
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return targetBN.mul(numBN).div(denomBN)
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}
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module.exports = {
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getStack,
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getEnvironmentType,
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sufficientBalance,
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hexToBn,
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bnToHex,
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BnMultiplyByFraction,
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}
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