bsv/lib/sig-operations.js

/**
 * PubKey Map
 * ==========
 *
 * A map from (transaction hash, output number) to (script chunk index, pubKey).
 * Whening signing a bitcoin transaction, we need to be able to sign an input
 * with the correct key and also we need to know where to put signature when we
 * get it. This mapping allows us to find the key for an associated input (which
 * is identified by tx output hash and number) with which to sign the
 * transaction and then also to know where to insert the signature into the
 * input script. This gets us the public key, and we need a different method to
 * get the private key. That is because we often know the public key to be used
 * but may not have access to the private key until the entire tx is sent to
 * where the private keys are.
 */
'use strict'

import { Struct } from './struct'
import { Sig } from './sig'

class SigOperations extends Struct {
  constructor (map = new Map()) {
    super({ map })
  }

  toJSON () {
    const json = {}
    this.map.forEach((arr, label) => {
      json[label] = arr.map(obj => ({
        nScriptChunk: obj.nScriptChunk,
        type: obj.type, // 'sig' or 'pubKey'
        addressStr: obj.addressStr,
        nHashType: obj.nHashType,
        log: obj.log
      }))
    })
    return json
  }

  fromJSON (json) {
    Object.keys(json).forEach(label => {
      this.map.set(label, json[label].map(obj => ({
        nScriptChunk: obj.nScriptChunk,
        type: obj.type,
        addressStr: obj.addressStr,
        nHashType: obj.nHashType,
        log: obj.log
      })))
    })
    return this
  }

  /**
   * Set an address to in the map for use with single-sig.
   *
   * @param {Buffer} txHashBuf The hash of a transsaction. Note that this is
   * *not* the reversed transaction id, but is the raw hash.
   * @param {Number} txOutNum The output number, a.k.a. the "vout".
   * @param {Number} nScriptChunk The index of the chunk of the script where
   * we are going to place the signature.
   * @param {String} addressStr The addressStr coresponding to this (txHashBuf,
   * txOutNum, nScriptChunk) where we are going to sign and insert the
   * signature or public key.
   * @param {Number} nHashType Usually = Sig.SIGHASH_ALL | Sig.SIGHASH_FORKID
   */
  setOne (txHashBuf, txOutNum, nScriptChunk, type = 'sig', addressStr, nHashType = Sig.SIGHASH_ALL | Sig.SIGHASH_FORKID) {
    const label = txHashBuf.toString('hex') + ':' + txOutNum
    const obj = { nScriptChunk, type, addressStr, nHashType }
    this.map.set(label, [obj])
    return this
  }

  /**
   * Set a bunch of addresses for signing an input such as for use with multi-sig.
   *
   * @param {Buffer} txHashBuf The hash of a transsaction. Note that this is
   * *not* the reversed transaction id, but is the raw hash.
   * @param {Number} txOutNum The output number, a.k.a. the "vout".
   * @param {Array} arr Must take the form of [{nScriptChunk, type, addressStr, nHashType}, ...]
   */
  setMany (txHashBuf, txOutNum, arr) {
    const label = txHashBuf.toString('hex') + ':' + txOutNum
    arr = arr.map(obj => ({
      type: obj.type || 'sig',
      nHashType: obj.nHashType || Sig.SIGHASH_ALL | Sig.SIGHASH_FORKID,
      ...obj
    }))
    this.map.set(label, arr)
    return this
  }

  addOne (txHashBuf, txOutNum, nScriptChunk, type = 'sig', addressStr, nHashType = Sig.SIGHASH_ALL | Sig.SIGHASH_FORKID) {
    const arr = this.get(txHashBuf, txOutNum) || []
    arr.push({
      nScriptChunk,
      type,
      addressStr,
      nHashType
    })
    this.setMany(txHashBuf, txOutNum, arr)
    return this
  }

  /**
   * Get an address from the map
   *
   * @param {Buffer} txHashBuf The hash of a transction. Note that this is *not*
   * the reversed transaction id, but is the raw hash.
   * @param {Number} txOutNum The output number, a.k.a. the "vout".
   * @param {Number} nScriptChunk The index of the chunk of the script where
   * we are going to place the signature.
   * @returns {PubKey}
   */
  get (txHashBuf, txOutNum) {
    const label = txHashBuf.toString('hex') + ':' + txOutNum
    return this.map.get(label)
  }
}

export { SigOperations }