/*!
* witness.js - witness object for hsd
* Copyright (c) 2017-2018, Christopher Jeffrey (MIT License).
* https://github.com/handshake-org/hsd
*/
'use strict';
const assert = require('bsert');
const bio = require('bufio');
const Script = require('./script');
const common = require('./common');
const util = require('../utils/util');
const Address = require('../primitives/address');
const consensus = require('../protocol/consensus');
const Stack = require('./stack');
const {encoding} = bio;
const scriptTypes = common.types;
/**
* Witness
* Refers to the witness vector of
* segregated witness transactions.
* @alias module:script.Witness
* @extends Stack
* @property {Buffer[]} items
* @property {Script?} redeem
* @property {Number} length
*/
class Witness extends Stack {
/**
* Create a witness.
* @alias module:script.Witness
* @constructor
* @param {Buffer[]|Object} items - Array of
* stack items.
* @property {Buffer[]} items
* @property {Script?} redeem
* @property {Number} length
*/
constructor(options) {
super();
if (options)
this.fromOptions(options);
}
/**
* Inject properties from options object.
* @private
* @param {Object} options
*/
fromOptions(options) {
assert(options, 'Witness data is required.');
if (Array.isArray(options))
return this.fromArray(options);
if (options.items)
return this.fromArray(options.items);
return this;
}
/**
* Convert witness to an array of buffers.
* @returns {Buffer[]}
*/
toArray() {
return this.items.slice();
}
/**
* Inject properties from an array of buffers.
* @private
* @param {Buffer[]} items
*/
fromArray(items) {
assert(Array.isArray(items));
this.items = items;
return this;
}
/**
* Insantiate witness from an array of buffers.
* @param {Buffer[]} items
* @returns {Witness}
*/
static fromArray(items) {
return new this().fromArray(items);
}
/**
* Convert witness to an array of buffers.
* @returns {Buffer[]}
*/
toItems() {
return this.items.slice();
}
/**
* Inject properties from an array of buffers.
* @private
* @param {Buffer[]} items
*/
fromItems(items) {
assert(Array.isArray(items));
this.items = items;
return this;
}
/**
* Insantiate witness from an array of buffers.
* @param {Buffer[]} items
* @returns {Witness}
*/
static fromItems(items) {
return new this().fromItems(items);
}
/**
* Convert witness to a stack.
* @returns {Stack}
*/
toStack() {
return new Stack(this.toArray());
}
/**
* Inject properties from a stack.
* @private
* @param {Stack} stack
*/
fromStack(stack) {
return this.fromArray(stack.items);
}
/**
* Insantiate witness from a stack.
* @param {Stack} stack
* @returns {Witness}
*/
static fromStack(stack) {
return new this().fromStack(stack);
}
/**
* Inspect a Witness object.
* @returns {String} Human-readable script.
*/
format() {
return `<Witness: ${this.toString()}>`;
}
/**
* Inject properties from witness.
* Used for cloning.
* @private
* @param {Witness} witness
* @returns {Witness}
*/
inject(witness) {
this.items = witness.items.slice();
return this;
}
/**
* Compile witness (NOP).
* @returns {Witness}
*/
compile() {
return this;
}
/**
* "Guess" the type of the witness.
* This method is not 100% reliable.
* @returns {ScriptType}
*/
getInputType() {
return scriptTypes.NONSTANDARD;
}
/**
* "Guess" the address of the witness.
* This method is not 100% reliable.
* @returns {Address|null}
*/
getInputAddress() {
return Address.fromWitness(this);
}
/**
* "Test" whether the witness is a pubkey input.
* Always returns false.
* @returns {Boolean}
*/
isPubkeyInput() {
return false;
}
/**
* Get P2PK signature if present.
* Always returns null.
* @returns {Buffer|null}
*/
getPubkeyInput() {
return null;
}
/**
* "Guess" whether the witness is a pubkeyhash input.
* This method is not 100% reliable.
* @returns {Boolean}
*/
isPubkeyhashInput() {
return this.items.length === 2
&& common.isSignatureEncoding(this.items[0])
&& common.isKeyEncoding(this.items[1]);
}
/**
* Get P2PKH signature and key if present.
* @returns {Array} [sig, key]
*/
getPubkeyhashInput() {
if (!this.isPubkeyhashInput())
return [null, null];
return [this.items[0], this.items[1]];
}
/**
* "Test" whether the witness is a multisig input.
* Always returns false.
* @returns {Boolean}
*/
isMultisigInput() {
return false;
}
/**
* Get multisig signatures key if present.
* Always returns null.
* @returns {Buffer[]|null}
*/
getMultisigInput() {
return null;
}
/**
* "Guess" whether the witness is a scripthash input.
* This method is not 100% reliable.
* @returns {Boolean}
*/
isScripthashInput() {
return this.items.length > 0 && !this.isPubkeyhashInput();
}
/**
* Get P2SH redeem script if present.
* @returns {Buffer|null}
*/
getScripthashInput() {
if (!this.isScripthashInput())
return null;
return this.items[this.items.length - 1];
}
/**
* "Guess" whether the witness is an unknown/non-standard type.
* This method is not 100% reliable.
* @returns {Boolean}
*/
isUnknownInput() {
return this.getInputType() === scriptTypes.NONSTANDARD;
}
/**
* Test the witness against a bloom filter.
* @param {Bloom} filter
* @returns {Boolean}
*/
test(filter) {
for (const item of this.items) {
if (item.length === 0)
continue;
if (filter.test(item))
return true;
}
return false;
}
/**
* Grab and deserialize the redeem script from the witness.
* @returns {Script} Redeem script.
*/
getRedeem() {
if (this.items.length === 0)
return null;
const redeem = this.items[this.items.length - 1];
if (!redeem)
return null;
return Script.decode(redeem);
}
/**
* Find a data element in a witness.
* @param {Buffer} data - Data element to match against.
* @returns {Number} Index (`-1` if not present).
*/
indexOf(data) {
for (let i = 0; i < this.items.length; i++) {
const item = this.items[i];
if (item.equals(data))
return i;
}
return -1;
}
/**
* Calculate size of the witness
* excluding the varint size bytes.
* @returns {Number}
*/
getSize() {
let size = 0;
for (const item of this.items)
size += encoding.sizeVarBytes(item);
return size;
}
/**
* Calculate size of the witness
* including the varint size bytes.
* @returns {Number}
*/
getVarSize() {
return encoding.sizeVarint(this.items.length) + this.getSize();
}
/**
* Write witness to a buffer writer.
* @param {BufferWriter} bw
*/
write(bw) {
bw.writeVarint(this.items.length);
for (const item of this.items)
bw.writeVarBytes(item);
return bw;
}
/**
* Encode witness.
* @returns {Buffer}
*/
encode() {
const bw = bio.write(this.getVarSize());
this.write(bw);
return bw.render();
}
/**
* Convert witness to a hex string.
* @returns {String}
*/
getJSON() {
const items = [];
for (const item of this.items)
items.push(item.toString('hex'));
return items;
}
/**
* Inject properties from json object.
* @private
* @param {String} json
*/
fromJSON(json) {
assert(json && Array.isArray(json), 'Covenant must be an object.');
for (const str of json) {
const item = util.parseHex(str, -1);
this.items.push(item);
}
return this;
}
/**
* Inject properties from buffer reader.
* @private
* @param {BufferReader} br
*/
read(br) {
const count = br.readVarint();
if (count > consensus.MAX_SCRIPT_STACK)
throw new Error('Too many witness items.');
for (let i = 0; i < count; i++)
this.items.push(br.readVarBytes());
return this;
}
/**
* Inject items from string.
* @private
* @param {String|String[]} items
*/
fromString(items) {
if (!Array.isArray(items)) {
assert(typeof items === 'string');
items = items.trim();
if (items.length === 0)
return this;
items = items.split(/\s+/);
}
for (const item of items)
this.items.push(util.parseHex(item, -1));
return this;
}
/**
* Test an object to see if it is a Witness.
* @param {Object} obj
* @returns {Boolean}
*/
static isWitness(obj) {
return obj instanceof Witness;
}
}
/*
* Expose
*/
module.exports = Witness;