Differential D13916 Diff 40442 apps/alias-server/src/utils.js

Changeset View

Standalone View

apps/alias-server/src/utils.js

// Copyright (c) 2023 The Bitcoin developers		// Copyright (c) 2023 The Bitcoin developers
// Distributed under the MIT software license, see the accompanying		// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.		// file COPYING or http://www.opensource.org/licenses/mit-license.php.

'use strict';		'use strict';
		const opReturn = require('../constants/op_return');

module.exports = {		module.exports = {
getAliasFromHex: function (aliasHex) {		getAliasFromHex: function (aliasHex) {
return Buffer.from(aliasHex, 'hex').toString('utf8');		return Buffer.from(aliasHex, 'hex').toString('utf8');
},		},
getHexFromAlias: function (alias) {		getHexFromAlias: function (alias) {
return Buffer.from(alias, 'utf8').toString('hex');		return Buffer.from(alias, 'utf8').toString('hex');
},		},
Show All 17 Lines	removeUnconfirmedTxsFromTxHistory: function (txHistory) {
confirmedTxHistory.push(thisTx);		confirmedTxHistory.push(thisTx);
}		}
}		}
return confirmedTxHistory;		return confirmedTxHistory;
},		},
wait: async function (msecs) {		wait: async function (msecs) {
await new Promise(resolve => setTimeout(resolve, msecs));		await new Promise(resolve => setTimeout(resolve, msecs));
},		},
		/**
		* Get the next push from an OP_RETURN stack of a version 0 alias registration tx
		* @param {object} stackObj {remainingHex: remaining stack as hex string}
		* @param {string}
		* @returns {string} the next push on the stack
		* @modifies stackObj, removes the returned push
		* @throws {Error}
		*/
		getNextPush: function (stack) {
		let remainingHex = stack.remainingHex;

		const byteLength = 2; // one byte is 2 characters of a hex string

		// Get the first byte on the stack
		let firstByte = remainingHex.slice(0, 1 * byteLength);

		// Remove firstByte from remainingHex
		remainingHex = remainingHex.slice(1 * byteLength);

		if (firstByte === opReturn.OP_RETURN) {
		// If the first byte is '6a', reassign firstByte
		// 6a just means this is the first push of an OP_RETURN

		// Re-assign firstByte
		firstByte = remainingHex.slice(0, 1 * byteLength);

		// Remove 6a from remainingHex
		remainingHex = remainingHex.slice(1 * byteLength);
		}

		// Initialize pushdata, the byteCount in hex of the push
		let pushdata;

		if (opReturn.oneByteStackAdds.includes(firstByte)) {
		/**
		* If this is a one-byte push, return the byte
		* Modify the { stack } input in place
		*/

		stack.remainingHex = remainingHex;
		return firstByte;
		}

		if (opReturn.oneBytePushdatas.includes(firstByte)) {
		// If the first byte on the stack is 0x01-0x4b, then this is pushdata
		pushdata = firstByte;
		} else if (firstByte === opReturn.OP_PUSHDATA1) {
		// The next byte contains the number of bytes to be pushed onto the stack.
		pushdata = remainingHex.slice(0, 1 * byteLength);

		// Remove 1 byte pushdata from the stack
		remainingHex = remainingHex.slice(1 * byteLength);
		} else if (firstByte === opReturn.OP_PUSHDATA2) {
		// The next two bytes contain the number of bytes to be pushed onto the stack in little endian order.
		// Note: version 0 alias registration txs do not require more than one byte of pushdata
		// So, if the other byte is not 0x00, throw an error
		if (remainingHex.slice(1 * byteLength, 2 * byteLength) !== '00') {
		throw new Error(
		'Version 0 alias registrations cannot have pushdata > 255',
		);
		}

		// pushdata is the first byte of the next 2 bytes, as little-endian
		// i.e. 04 would be 0x04 0x00
		pushdata = remainingHex.slice(0, 1 * byteLength);

		// Remove 2 bytes pushdata from the stack
		remainingHex = remainingHex.slice(2 * byteLength);
		} else if (firstByte === opReturn.OP_PUSHDATA4) {
		// The next four bytes contain the number of bytes to be pushed onto the stack in little endian order.
		// Note: version 0 alias registration txs do not require more than one byte of pushdata
		// So, if the other three bytes are not 0x00, throw an error
		if (
		remainingHex.slice(1 * byteLength, 4 * byteLength) !== '000000'
		) {
		throw new Error(
		'Version 0 alias registrations cannot have pushdata > 255',
		);
		}

		// pushdata is the first byte of the next 4 bytes, as little-endian
		// i.e. 04 would be 0x04 0x00
		pushdata = remainingHex.slice(0, 2);
		// Remove 4 bytes pushdata from the stack
		remainingHex = remainingHex.slice(4 * byteLength);
		} else {
		throw new Error(`${firstByte} is invalid pushdata`);
		}

		// Now that you know pushdata in bytes, get the push
		const pushdataBytes = parseInt(pushdata, 16);

		// Modify the {stack} input in place
		stack.remainingHex = remainingHex.slice(pushdataBytes * byteLength);

		// Return the push
		return remainingHex.slice(0, pushdataBytes * byteLength);
		},
};		};