bitcoincashjs/Script.js

var imports     = require('soop').imports();
var config      = imports.config || require('./config');
var log         = imports.log || require('./util/log');
var Opcode      = imports.Opcode || require('./Opcode');
var buffertools = imports.buffertools || require('buffertools');

// Make opcodes available as pseudo-constants
for (var i in Opcode.map) {
  eval(i + " = " + Opcode.map[i] + ";");
}

var util   = imports.util || require('./util/util');
var Parser = imports.Parser || require('./util/BinaryParser');
var Put    = imports.Put || require('bufferput');

var TX_UNKNOWN = 0;
var TX_PUBKEY = 1;
var TX_PUBKEYHASH = 2;
var TX_MULTISIG = 3;
var TX_SCRIPTHASH = 4;

var TX_TYPES = [
  'unknown',
  'pubkey',
  'pubkeyhash',
  'multisig',
  'scripthash'
];

function Script(buffer) {
  if (buffer) {
    this.buffer = buffer;
  } else {
    this.buffer = util.EMPTY_BUFFER;
  }
  this.chunks = [];
  this.parse();
};
this.class = Script;

Script.TX_UNKNOWN = TX_UNKNOWN;
Script.TX_PUBKEY = TX_PUBKEY;
Script.TX_PUBKEYHASH = TX_PUBKEYHASH;
Script.TX_MULTISIG = TX_MULTISIG;
Script.TX_SCRIPTHASH = TX_SCRIPTHASH;

Script.prototype.parse = function() {
  this.chunks = [];

  var parser = new Parser(this.buffer);
  while (!parser.eof()) {
    var opcode = parser.word8();

    var len;
    if (opcode > 0 && opcode < OP_PUSHDATA1) {
      // Read some bytes of data, opcode value is the length of data
      this.chunks.push(parser.buffer(opcode));
    } else if (opcode == OP_PUSHDATA1) {
      len = parser.word8();
      this.chunks.push(parser.buffer(len));
    } else if (opcode == OP_PUSHDATA2) {
      len = parser.word16le();
      this.chunks.push(parser.buffer(len));
    } else if (opcode == OP_PUSHDATA4) {
      len = parser.word32le();
      this.chunks.push(parser.buffer(len));
    } else {
      this.chunks.push(opcode);
    }
  }
};

Script.prototype.isPushOnly = function() {
  for (var i = 0; i < this.chunks.length; i++)
    if (!Buffer.isBuffer(this.chunks[i]))
      return false;

  return true;
};

Script.prototype.isP2SH = function() {
  return (this.chunks.length == 3 &&
    this.chunks[0] == OP_HASH160 &&
    Buffer.isBuffer(this.chunks[1]) &&
    this.chunks[1].length == 20 &&
    this.chunks[2] == OP_EQUAL);
};

Script.prototype.isPubkey = function() {
  return (this.chunks.length == 2 &&
    Buffer.isBuffer(this.chunks[0]) &&
    this.chunks[1] == OP_CHECKSIG);
};

Script.prototype.isPubkeyHash = function() {
  return (this.chunks.length == 5 &&
    this.chunks[0] == OP_DUP &&
    this.chunks[1] == OP_HASH160 &&
    Buffer.isBuffer(this.chunks[2]) &&
    this.chunks[2].length == 20 &&
    this.chunks[3] == OP_EQUALVERIFY &&
    this.chunks[4] == OP_CHECKSIG);
};

function isSmallIntOp(opcode) {
  return ((opcode == OP_0) ||
    ((opcode >= OP_1) && (opcode <= OP_16)));
};

Script.prototype.isMultiSig = function() {
  return (this.chunks.length > 3 &&
    isSmallIntOp(this.chunks[0]) &&
    isSmallIntOp(this.chunks[this.chunks.length - 2]) &&
    this.chunks[this.chunks.length - 1] == OP_CHECKMULTISIG);
};

Script.prototype.finishedMultiSig = function() {
  var nsigs = 0;
  for (var i = 0; i < this.chunks.length - 1; i++)
    if (this.chunks[i] !== 0)
      nsigs++;

  var serializedScript = this.chunks[this.chunks.length - 1];
  var script = new Script(serializedScript);
  var nreq = script.chunks[0] - 80; //see OP_2-OP_16

  if (nsigs == nreq)
    return true;
  else
    return false;
};

Script.prototype.removePlaceHolders = function() {
  var chunks = [];
  for (var i in this.chunks) {
    if (this.chunks.hasOwnProperty(i)) {
      var chunk = this.chunks[i];
      if (chunk != 0)
        chunks.push(chunk);
    }
  }
  this.chunks = chunks;
  this.updateBuffer();
  return this;
};

Script.prototype.prependOp0 = function() {
  var chunks = [0];
  for (i in this.chunks) {
    if (this.chunks.hasOwnProperty(i)) {
      chunks.push(this.chunks[i]);
    }
  }
  this.chunks = chunks;
  this.updateBuffer();
  return this;
};

// is this a script form we know?
Script.prototype.classify = function() {
  if (this.isPubkeyHash())
    return TX_PUBKEYHASH;
  if (this.isP2SH())
    return TX_SCRIPTHASH;
  if (this.isMultiSig())
    return TX_MULTISIG;
  if (this.isPubkey())
    return TX_PUBKEY;
  return TX_UNKNOWN;
};

// extract useful data items from known scripts
Script.prototype.capture = function() {
  var txType = this.classify();
  var res = [];
  switch (txType) {
    case TX_PUBKEY:
      res.push(this.chunks[0]);
      break;
    case TX_PUBKEYHASH:
      res.push(this.chunks[2]);
      break;
    case TX_MULTISIG:
      for (var i = 1; i < (this.chunks.length - 2); i++)
        res.push(this.chunks[i]);
      break;
    case TX_SCRIPTHASH:
      res.push(this.chunks[1]);
      break;

    case TX_UNKNOWN:
    default:
      // do nothing
      break;
  }

  return res;
};

// return first extracted data item from script
Script.prototype.captureOne = function() {
  var arr = this.capture();
  return arr[0];
};

Script.prototype.getOutType = function() {
  var txType = this.classify();
  switch (txType) {
    case TX_PUBKEY:
      return 'Pubkey';
    case TX_PUBKEYHASH:
      return 'Address';
    default:
      return 'Strange';
  }
};

Script.prototype.getRawOutType = function() {
  return TX_TYPES[this.classify()];
};

Script.prototype.simpleOutHash = function() {
  switch (this.getOutType()) {
    case 'Address':
      return this.chunks[2];
    case 'Pubkey':
      return util.sha256ripe160(this.chunks[0]);
    default:
      log.debug("Encountered non-standard scriptPubKey");
      log.debug("Strange script was: " + this.toString());
      return null;
  }
};

Script.prototype.getInType = function() {
  if (this.chunks.length == 1) {
    // Direct IP to IP transactions only have the public key in their scriptSig.
    return 'Pubkey';
  } else if (this.chunks.length == 2 &&
    Buffer.isBuffer(this.chunks[0]) &&
    Buffer.isBuffer(this.chunks[1])) {
    return 'Address';
  } else {
    return 'Strange';
  }
};

Script.prototype.simpleInPubKey = function() {
  switch (this.getInType()) {
    case 'Address':
      return this.chunks[1];
    case 'Pubkey':
      return null;
    default:
      log.debug("Encountered non-standard scriptSig");
      log.debug("Strange script was: " + this.toString());
      return null;
  }
};

Script.prototype.getBuffer = function() {
  return this.buffer;
};

Script.prototype.getStringContent = function(truncate, maxEl) {
  if (truncate === null) {
    truncate = true;
  }

  if ('undefined' === typeof maxEl) {
    maxEl = 15;
  }

  var s = '';
  for (var i = 0, l = this.chunks.length; i < l; i++) {
    var chunk = this.chunks[i];

    if (i > 0) {
      s += ' ';
    }

    if (Buffer.isBuffer(chunk)) {
      s += '0x' + util.formatBuffer(chunk, truncate ? null : 0);
    } else {
      s += Opcode.reverseMap[chunk];
    }

    if (maxEl && i > maxEl) {
      s += ' ...';
      break;
    }
  }
  return s;
};

Script.prototype.toString = function(truncate, maxEl) {
  var script = "<Script ";
  script += this.getStringContent(truncate, maxEl);
  script += ">";
  return script;
};

Script.prototype.writeOp = function(opcode) {
  var buf = Buffer(this.buffer.length + 1);
  this.buffer.copy(buf);
  buf.writeUInt8(opcode, this.buffer.length);

  this.buffer = buf;

  this.chunks.push(opcode);
};

Script.prototype.writeN = function(n) {
  if (n < 0 || n > 16)
    throw new Error("writeN: out of range value " + n);

  if (n == 0)
    this.writeOp(OP_0);
  else
    this.writeOp(OP_1 + n - 1);
};

function prefixSize(data_length) {
  if (data_length < OP_PUSHDATA1) {
    return 1;
  } else if (data_length <= 0xff) {
    return 1 + 1;
  } else if (data_length <= 0xffff) {
    return 1 + 2;
  } else {
    return 1 + 4;
  }
};

function encodeLen(data_length) {
  var buf = undefined;
  if (data_length < OP_PUSHDATA1) {
    buf = new Buffer(1);
    buf.writeUInt8(data_length, 0);
  } else if (data_length <= 0xff) {
    buf = new Buffer(1 + 1);
    buf.writeUInt8(OP_PUSHDATA1, 0);
    buf.writeUInt8(data_length, 1);
  } else if (data_length <= 0xffff) {
    buf = new Buffer(1 + 2);
    buf.writeUInt8(OP_PUSHDATA2, 0);
    buf.writeUInt16LE(data_length, 1);
  } else {
    buf = new Buffer(1 + 4);
    buf.writeUInt8(OP_PUSHDATA4, 0);
    buf.writeUInt32LE(data_length, 1);
  }

  return buf;
};

Script.prototype.writeBytes = function(data) {
  var newSize = this.buffer.length + prefixSize(data.length) + data.length;
  this.buffer = Buffer.concat([this.buffer, encodeLen(data.length), data]);
  this.chunks.push(data);
};

Script.prototype.updateBuffer = function() {
  this.buffer = Script.chunksToBuffer(this.chunks);
};

Script.prototype.findAndDelete = function(chunk) {
  var dirty = false;
  if (Buffer.isBuffer(chunk)) {
    for (var i = 0, l = this.chunks.length; i < l; i++) {
      if (Buffer.isBuffer(this.chunks[i]) &&
        buffertools.compare(this.chunks[i], chunk) === 0) {
        this.chunks.splice(i, 1);
        dirty = true;
      }
    }
  } else if ("number" === typeof chunk) {
    for (var i = 0, l = this.chunks.length; i < l; i++) {
      if (this.chunks[i] === chunk) {
        this.chunks.splice(i, 1);
        dirty = true;
      }
    }
  } else {
    throw new Error("Invalid chunk datatype.");
  }
  if (dirty) {
    this.updateBuffer();
  }
};

/**
 * Creates a simple OP_CHECKSIG with pubkey output script.
 *
 * These are used for coinbase transactions and at some point were used for
 * IP-based transactions as well.
 */
Script.createPubKeyOut = function(pubkey) {
  var script = new Script();
  script.writeBytes(pubkey);
  script.writeOp(OP_CHECKSIG);
  return script;
};

/**
 * Creates a standard txout script.
 */
Script.createPubKeyHashOut = function(pubKeyHash) {
  var script = new Script();
  script.writeOp(OP_DUP);
  script.writeOp(OP_HASH160);
  script.writeBytes(pubKeyHash);
  script.writeOp(OP_EQUALVERIFY);
  script.writeOp(OP_CHECKSIG);
  return script;
};

Script.createMultisig = function(n_required, keys) {
  var script = new Script();
  script.writeN(n_required);
  keys.forEach(function(key) {
    script.writeBytes(key);
  });
  script.writeN(keys.length);
  script.writeOp(OP_CHECKMULTISIG);
  return script;
};

Script.createP2SH = function(scriptHash) {
  var script = new Script();
  script.writeOp(OP_HASH160);
  script.writeBytes(scriptHash);
  script.writeOp(OP_EQUAL);
  return script;
};

Script.fromTestData = function(testData) {
  testData = testData.map(function(chunk) {
    if ("string" === typeof chunk) {
      return new Buffer(chunk, 'hex');
    } else {
      return chunk;
    }
  });

  var script = new Script();
  script.chunks = testData;
  script.updateBuffer();
  return script;
};

Script.fromChunks = function(chunks) {
  var script = new Script();
  script.chunks = chunks;
  script.updateBuffer();
  return script;
};

Script.fromHumanReadable = function(s) {
  return new Script(Script.stringToBuffer(s));
};

Script.prototype.toHumanReadable = function() {
  var s = '';
  for (var i = 0, l = this.chunks.length; i < l; i++) {
    var chunk = this.chunks[i];

    if (i > 0) {
      s += ' ';
    }

    if (Buffer.isBuffer(chunk)) {
      if (chunk.length === 0) {
        s += '0';
      } else {
        s += '0x' + util.formatBuffer(encodeLen(chunk.length), 0) + ' ';
        s += '0x' + util.formatBuffer(chunk, 0);
      }
    } else {
      var opcode = Opcode.reverseMap[chunk];
      if (typeof opcode === 'undefined') {
        opcode = '0x'+chunk.toString(16);
      }
      s += opcode;
    }
  }
  return s;
    
};

Script.stringToBuffer = function(s) {
  var buf = new Put();
  var split = s.split(' ');
  for (var i = 0; i < split.length; i++) {
    var word = split[i];
    if (word === '') continue;
    if (word.length > 2 && word.substring(0, 2) === '0x') {
      // raw hex value
      //console.log('hex value');
      buf.put(new Buffer(word.substring(2, word.length), 'hex'));
    } else {
      var opcode = Opcode.map['OP_' + word];
      if (typeof opcode !== 'undefined') {
        // op code in string form
        //console.log('opcode');
        buf.word8(opcode);
      } else {
        var integer = parseInt(word);
        if (!isNaN(integer)) {
          // integer
          //console.log('integer');
          var data = util.intToBuffer(integer);
          buf.put(Script.chunksToBuffer([data]));
        } else if (word[0] === '\'' && word[word.length-1] === '\'') {
          // string
          //console.log('string');
          word = word.substring(1,word.length-1);
          var hexString = '';
          for(var c=0;c<word.length;c++) {
            hexString += ''+word.charCodeAt(c).toString(16);
          }
          buf.put(Script.chunksToBuffer([new Buffer(word)]));
        } else {
          throw new Error('Could not parse word "' +word+'" from script "'+s+'"');
        }
      }
    }
  }
  return buf.buffer();
};

Script.chunksToBuffer = function(chunks) {
  var buf = new Put();

  for (var i = 0, l = chunks.length; i < l; i++) {
    var data = chunks[i];
    if (Buffer.isBuffer(data)) {
      if (data.length < OP_PUSHDATA1) {
        buf.word8(data.length);
      } else if (data.length <= 0xff) {
        buf.word8(OP_PUSHDATA1);
        buf.word8(data.length);
      } else if (data.length <= 0xffff) {
        buf.word8(OP_PUSHDATA2);
        buf.word16le(data.length);
      } else {
        buf.word8(OP_PUSHDATA4);
        buf.word32le(data.length);
      }
      buf.put(data);
    } else if ("number" === typeof data) {
      buf.word8(data);
    } else {
      throw new Error("Script.chunksToBuffer(): Invalid chunk datatype");
    }
  }
  return buf.buffer();
};



module.exports = require('soop')(Script);