diff --git a/CHANGELOG.md b/CHANGELOG.md index 4b4218210..a60e1245c 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -2,6 +2,8 @@ ## Current Master +- Estimating gas limit for simple ether sends now faster & cheaper, by avoiding VM usage on recipients with no code. + ## 3.13.4 2018-1-9 - Remove recipient field if application initializes a tx with an empty string, or 0x, and tx data. Throw an error with the same condition, but without tx data. diff --git a/app/scripts/lib/tx-gas-utils.js b/app/scripts/lib/tx-gas-utils.js index 5e49fdb22..d57c70b10 100644 --- a/app/scripts/lib/tx-gas-utils.js +++ b/app/scripts/lib/tx-gas-utils.js @@ -4,6 +4,7 @@ const { BnMultiplyByFraction, bnToHex, } = require('./util') +const SIMPLE_GAS_COST = '0x5208' // Hex for 21000, cost of a simple send. /* tx-utils are utility methods for Transaction manager @@ -37,14 +38,30 @@ module.exports = class txProvideUtil { async estimateTxGas (txMeta, blockGasLimitHex) { const txParams = txMeta.txParams + // check if gasLimit is already specified txMeta.gasLimitSpecified = Boolean(txParams.gas) - // if not, fallback to block gasLimit - if (!txMeta.gasLimitSpecified) { - const blockGasLimitBN = hexToBn(blockGasLimitHex) - const saferGasLimitBN = BnMultiplyByFraction(blockGasLimitBN, 19, 20) - txParams.gas = bnToHex(saferGasLimitBN) + + // if it is, use that value + if (txMeta.gasLimitSpecified) { + return txParams.gas } + + // if recipient has no code, gas is 21k max: + const recipient = txParams.to + const hasRecipient = Boolean(recipient) + const code = await this.query.getCode(recipient) + if (hasRecipient && (!code || code === '0x')) { + txParams.gas = SIMPLE_GAS_COST + txMeta.gasLimitSpecified = 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) }