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Block.js
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Block.js
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var imports = require('soop').imports();
var util = imports.util || require('../util');
var Debug1 = imports.Debug1 || function() {};
var Script = imports.Script || require('./Script');
var Bignum = imports.Bignum || require('bignum');
var Binary = imports.Binary || require('binary');
var Step = imports.Step || require('step');
var buffertools = imports.buffertools || require('buffertools');
var Transaction = imports.Transaction || require('./Transaction');
var TransactionIn = Transaction.In;
var TransactionOut = Transaction.Out;
var COINBASE_OP = Transaction.COINBASE_OP;
var VerificationError = imports.VerificationError || require('../util/error').VerificationError;
var BlockRules = {
maxTimeOffset: 2 * 60 * 60, // How far block timestamps can be into the future
//largestHash: (new Bignum(2)).pow(256)
//largestHash: new Bignum('115792089237316195423570985008687907853269984665640564039457584007913129639936') // = 2^256
largestHash: new Bignum('10000000000000000000000000000000000000000000000000000000000000000', 16)
};
function Block(data) {
if ("object" !== typeof data) {
data = {};
}
this.hash = data.hash || null;
this.prev_hash = data.prev_hash || util.NULL_HASH;
this.merkle_root = data.merkle_root || util.NULL_HASH;
this.timestamp = data.timestamp || 0;
this.bits = data.bits || 0;
this.nonce = data.nonce || 0;
this.version = data.version || 0;
this.height = data.height || 0;
this.size = data.size || 0;
this.active = data.active || false;
this.chainWork = data.chainWork || util.EMPTY_BUFFER;
this.txs = data.txs || [];
}
Block.prototype.getHeader = function getHeader() {
var buf = new Buffer(80);
var ofs = 0;
buf.writeUInt32LE(this.version, ofs);
ofs += 4;
this.prev_hash.copy(buf, ofs);
ofs += 32;
this.merkle_root.copy(buf, ofs);
ofs += 32;
buf.writeUInt32LE(this.timestamp, ofs);
ofs += 4;
buf.writeUInt32LE(this.bits, ofs);
ofs += 4;
buf.writeUInt32LE(this.nonce, ofs);
ofs += 4;
return buf;
};
Block.prototype.parse = function parse(parser, headerOnly) {
this.version = parser.word32le();
this.prev_hash = parser.buffer(32);
this.merkle_root = parser.buffer(32);
this.timestamp = parser.word32le();
this.bits = parser.word32le();
this.nonce = parser.word32le();
this.txs = [];
this.size = 0;
if (headerOnly)
return;
var txCount = parser.varInt();
for (var i = 0; i < txCount; i++) {
var tx = new Transaction();
tx.parse(parser);
this.txs.push(tx);
}
};
Block.prototype.calcHash = function calcHash() {
var header = this.getHeader();
return util.twoSha256(header);
};
Block.prototype.checkHash = function checkHash() {
if (!this.hash || !this.hash.length) return false;
return buffertools.compare(this.calcHash(), this.hash) == 0;
};
Block.prototype.getHash = function getHash() {
if (!this.hash || !this.hash.length) this.hash = this.calcHash();
return this.hash;
};
Block.prototype.checkProofOfWork = function checkProofOfWork() {
var target = util.decodeDiffBits(this.bits);
// TODO: Create a compare method in node-buffertools that uses the correct
// endian so we don't have to reverse both buffers before comparing.
var reverseHash = buffertools.reverse(this.hash);
if (buffertools.compare(reverseHash, target) > 0) {
throw new VerificationError('Difficulty target not met');
}
return true;
};
/**
* Returns the amount of work that went into this block.
*
* Work is defined as the average number of tries required to meet this
* block's difficulty target. For example a target that is greater than 5%
* of all possible hashes would mean that 20 "work" is required to meet it.
*/
Block.prototype.getWork = function getWork() {
var target = util.decodeDiffBits(this.bits, true);
return BlockRules.largestHash.div(target.add(new Bignum(1)));
};
Block.prototype.checkTimestamp = function checkTimestamp() {
var currentTime = new Date().getTime() / 1000;
if (this.timestamp > currentTime + BlockRules.maxTimeOffset) {
throw new VerificationError('Timestamp too far into the future');
}
return true;
};
Block.prototype.checkTransactions = function checkTransactions(txs) {
if (!Array.isArray(txs) || txs.length <= 0) {
throw new VerificationError('No transactions');
}
if (!txs[0].isCoinBase()) {
throw new VerificationError('First tx must be coinbase');
}
for (var i = 1; i < txs.length; i++) {
if (txs[i].isCoinBase()) {
throw new VerificationError('Tx index ' + i + ' must not be coinbase');
}
}
return true;
};
/**
* Build merkle tree.
*
* Ported from Java. Original code: BitcoinJ by Mike Hearn
* Copyright (c) 2011 Google Inc.
*/
Block.prototype.getMerkleTree = function getMerkleTree(txs) {
// The merkle hash is based on a tree of hashes calculated from the transactions:
//
// merkleHash
// /\
// / \
// A B
// / \ / \
// tx1 tx2 tx3 tx4
//
// Basically transactions are hashed, then the hashes of the transactions are hashed
// again and so on upwards into the tree. The point of this scheme is to allow for
// disk space savings later on.
//
// This function is a direct translation of CBlock::BuildMerkleTree().
if (txs.length == 0) {
return [util.NULL_HASH.slice(0)];
}
// Start by adding all the hashes of the transactions as leaves of the tree.
var tree = txs.map(function(tx) {
return tx instanceof Transaction ? tx.getHash() : tx;
});
var j = 0;
// Now step through each level ...
for (var size = txs.length; size > 1; size = Math.floor((size + 1) / 2)) {
// and for each leaf on that level ..
for (var i = 0; i < size; i += 2) {
var i2 = Math.min(i + 1, size - 1);
var a = tree[j + i];
var b = tree[j + i2];
tree.push(util.twoSha256(Buffer.concat([a, b])));
}
j += size;
}
return tree;
};
Block.prototype.calcMerkleRoot = function calcMerkleRoot(txs) {
var tree = this.getMerkleTree(txs);
return tree[tree.length - 1];
};
Block.prototype.checkMerkleRoot = function checkMerkleRoot(txs) {
if (!this.merkle_root || !this.merkle_root.length) {
throw new VerificationError('No merkle root');
}
if (buffertools.compare(this.calcMerkleRoot(txs), new Buffer(this.merkle_root)) !== 0) {
throw new VerificationError('Merkle root incorrect');
}
return true;
};
Block.prototype.checkBlock = function checkBlock(txs) {
if (!this.checkHash()) {
throw new VerificationError("Block hash invalid");
}
this.checkProofOfWork();
this.checkTimestamp();
if (txs) {
this.checkTransactions(txs);
if (!this.checkMerkleRoot(txs)) {
throw new VerificationError("Merkle hash invalid");
}
}
return true;
};
Block.getBlockValue = function getBlockValue(height) {
var subsidy = 50 * util.COIN;
subsidy = subsidy / (Math.pow(2, Math.floor(height / 210000)));
subsidy = Math.floor(subsidy);
subsidy = new Bignum(subsidy);
return subsidy;
};
Block.prototype.getBlockValue = function getBlockValue() {
return Block.getBlockValue(this.height);
};
Block.prototype.toString = function toString() {
return "<Block " + util.formatHashAlt(this.hash) + " height=" + this.height + ">";
};
Block.prototype.createCoinbaseTx =
function createCoinbaseTx(beneficiary) {
var tx = new Transaction();
tx.ins.push(new TransactionIn({
s: util.EMPTY_BUFFER,
q: 0xffffffff,
o: COINBASE_OP
}));
tx.outs.push(new TransactionOut({
v: util.bigIntToValue(this.getBlockValue()),
s: Script.createPubKeyOut(beneficiary).getBuffer()
}));
return tx;
};
Block.prototype.solve = function solve(miner, callback) {
var header = this.getHeader();
var target = util.decodeDiffBits(this.bits);
miner.solve(header, target, callback);
};
/**
* Returns an object with the same field names as jgarzik's getblock patch.
*/
Block.prototype.getStandardizedObject =
function getStandardizedObject(txs) {
var block = {
hash: util.formatHashFull(this.getHash()),
version: this.version,
prev_block: util.formatHashFull(this.prev_hash),
mrkl_root: util.formatHashFull(this.merkle_root),
time: this.timestamp,
bits: this.bits,
nonce: this.nonce,
height: this.height
};
if (txs) {
var mrkl_tree = this.getMerkleTree(txs).map(function(buffer) {
return util.formatHashFull(buffer);
});
block.mrkl_root = mrkl_tree[mrkl_tree.length - 1];
block.n_tx = txs.length;
var totalSize = 80; // Block header
totalSize += util.getVarIntSize(txs.length); // txn_count
txs = txs.map(function(tx) {
tx = tx.getStandardizedObject();
totalSize += tx.size;
return tx;
});
block.size = totalSize;
block.tx = txs;
block.mrkl_tree = mrkl_tree;
} else {
block.size = this.size;
}
return block;
};
module.exports = require('soop')(Block);