miner mines continuously,
moved to an account model, transactions working, querying working, more checking of valid data
This commit is contained in:
Josip Milovac
parent
59bb42be11
commit
9847b2056b
12 changed files with 663 additions and 365 deletions
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@ -1,81 +1,276 @@
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const Block = require('./block');
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const N3 = require('n3');
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const DataFactory = require('n3').DataFactory;
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const Transaction = require('../wallet/transaction');
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const { MINING_REWARD } = require('../config');
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function getBalanceCopyGeneric(publicKey, maps) {
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for (const map of maps) {
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if (map.hasOwnProperty(publicKey)) {
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const found = map[publicKey];
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return {
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balance: found.balance,
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counter: found.counter
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};
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}
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}
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return {
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balance: 0,
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counter: 0
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};
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}
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function verifyBlock(prevBalances, prevBlock, verifyingBlock) {
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if (verifyingBlock.lastHash !== prevBlock.hash) {
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return {
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result: false,
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reason: "last hash didn't match our last hash"
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};
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}
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//how to check if new block's timestamp is believable
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if (verifyingBlock.difficulty !== Block.adjustDifficulty(prevBlock, verifyingBlock.timestamp)) {
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return {
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result: false,
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reason: "difficulty is incorrect"
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};
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}
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if (!Block.checkHash(verifyingBlock)) {
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return {
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result: false,
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reason: "hash is invalid failed"
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};
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}
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const changedBalances = {};
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const rewardBalanceCopy = getBalanceCopyGeneric(verifyingBlock.reward, [prevBalances]);
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changedBalances[verifyingBlock.reward] = {
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balance: rewardBalanceCopy.balance + MINING_REWARD,
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counter: rewardBalanceCopy.counter
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};
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for (const transaction of Block.getTransactions(verifyingBlock)) {
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if (!Transaction.verify(transaction)) {
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return {
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result: false,
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reason: "couldn't verify a transaction" };
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}
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const inputBalance = getBalanceCopyGeneric(transaction.input, [changedBalances, prevBalances]);
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if (transaction.counter <= inputBalance.counter) {
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return {
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result: false,
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reason: "transaction has invalid counter"
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};
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}
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inputBalance.counter = transaction.counter;
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for (const output of transaction.outputs) {
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const outputBalance = getBalanceCopyGeneric(output.publicKey, [changedBalances, prevBalances]);
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if (output.amount > inputBalance.balance) {
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return {
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result: false,
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reason: "transaction spending more than they have"
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};
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}
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inputBalance.balance -= output.amount;
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outputBalance.balance += output.amount;
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changedBalances[output.publicKey] = outputBalance;
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}
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changedBalances[transaction.input] = inputBalance;
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}
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return {
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result: true,
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changedBalances: changedBalances
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};
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}
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function verifyChain(chain) {
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if (chain.length === 0) {
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return {
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result: false,
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reason: "zero length"
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};
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}
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if (JSON.stringify(chain[0]) !== JSON.stringify(Block.genesis())) {
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return {
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result: false,
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reason: "initial block isn't genesis"
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};
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}
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const balances = {};
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for (let i = 1; i < chain.length; i++) {
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const block = chain[i];
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const lastBlock = chain[i - 1];
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const verifyResult = verifyBlock(balances, lastBlock, block);
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if (verifyResult.result === false) {
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return {
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result: false,
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reason: `Chain is invalid on block ${i}: ${verifyResult.reason}`
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};
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}
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for (const publicKey in verifyResult.changedBalances) {
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balances[publicKey] = verifyResult.changedBalances[publicKey];
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}
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}
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return {
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result: true,
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balances: balances
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};
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}
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//returns the first index where the two chains differ
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function findChainDifference(oldChain, newChain) {
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for (let i = 1; i < oldChain.length; ++i) {
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if (oldChain[i].hash !== newChain[i].hash) {
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return i;
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}
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}
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return 1;
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}
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function addBlockMetadata(blockchain, block) {
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const metadatas = Block.getMetadatas(block);
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for (const key in metadatas) {
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const metadata = metadatas[key];
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if (!("SSNmetadata" in metadata)) {
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//assert?
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return;
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}
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var ssn = metadata.SSNmetadata;
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const parser = new N3.Parser();
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parser.parse(
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ssn,
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(error, quadN, prefixes) => {
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if (quadN) {
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blockchain.store.addQuad(DataFactory.quad(
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DataFactory.namedNode(quadN.subject.id),
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DataFactory.namedNode(quadN.predicate.id),
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DataFactory.namedNode(quadN.object.id),
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DataFactory.namedNode(block.hash)));
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}
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});
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}
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}
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class Blockchain {
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constructor() {
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this.chain = [Block.genesis()];
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this.balances = {};
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this.store = new N3.Store();
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}
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getBalanceCopy(publicKey) {
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return getBalanceCopyGeneric(publicKey, [this.balances]);
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}
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lastBlock() {
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return this.chain[this.chain.length - 1];
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}
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serialize() {
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return JSON.stringify(this.chain);
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}
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static deserialize(serialized) {
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const returning = new Blockchain();
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const replaceResult = returning.replaceChain(JSON.parse(serialized));
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if(!replaceResult.result) {
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//chain wasn't valid
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return null;
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} else {
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return returning;
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}
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}
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//adds an existing block to the blockchain, returns false if the block can't be added, true if it was added
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addBlock(newBlock) {
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if (newBlock.lastHash !== this.chain[this.chain.length - 1].hash) {
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console.log("Tried to add invalid block, last hash didn't match our last hash");
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return false;
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}
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//how to check if new block's timestamp is believable
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if (newBlock.difficulty !== Block.adjustDifficulty(this.chain[this.chain.length - 1], newBlock.timestamp)) {
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console.log("Tried to add invalid block, difficulty is incorrect");
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return false;
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}
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if (!Block.checkBlock(newBlock)) {
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console.log("Tried to add invalid block, block's hash doesn't match its contents");
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return false;
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}
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const verifyResult = verifyBlock(this.balances, this.lastBlock(), newBlock);
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if (!verifyResult.result) {
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console.log(`Couldn't add block: ${verifyResult.reason}`);
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return false;
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}
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//all seems to be good, persist
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this.chain.push(newBlock);
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console.log("Added new block: ");
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for (const publicKey in verifyResult.changedBalances) {
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this.balances[publicKey] = verifyResult.changedBalances[publicKey];
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}
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addBlockMetadata(this, newBlock);
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//console.log("Added new block");
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//console.log(newBlock);
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return true;
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}
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isValidChain(chain) {
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if (chain.length === 0) {
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return false;
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}
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if (JSON.stringify(chain[0]) !== JSON.stringify(Block.genesis())) {
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return false;
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}
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static isValidChain(chain) {
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const res = verifyChain(chain);
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for (let i=1; i<chain.length; i++) {
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const block = chain[i];
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const lastBlock = chain[i-1];
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if (block.lastHash !== lastBlock.hash ||
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block.hash !== Block.blockHash(block)) {
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return false;
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}
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if (!Block.checkBlock(block)) {
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return false;
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}
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}
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return true;
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return res.result;
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}
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//return null on fail, returns the index of where they differ
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//return false on fail, true on success
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//TODO: faster verification of the new chain by only verifying from divergence, would require saving some historical balance state
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replaceChain(newChain) {
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if (newChain.length <= this.chain.length) {
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console.log('Received chain is not longer than the current chain.');
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return false;
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} else if (!this.isValidChain(newChain)) {
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console.log('The received chain is not valid.');
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return false;
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return {
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result: false,
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reason: "Received chain is not longer than the current chain."
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};
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}
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const verifyResult = verifyChain(newChain);
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if (!verifyResult.result) {
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return {
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result: false,
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reason: `The received chain is not valid: ${verifyResult.reason}`
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};
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}
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console.log('Replacing blockchain with the new chain.');
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//Replacing blockchain with the new chain
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const oldChain = this.chain;
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this.chain = newChain;
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//find where they differ
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for (let i = 1; i < oldChain.length; ++i) {
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if (oldChain[i].hash !== newChain[i].hash) {
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return i;
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}
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const chainDifference = findChainDifference(oldChain, newChain);
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console.log(`chain difference was ${chainDifference}`);
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//fix metadata
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for (let i = oldChain.length - 1; i >= chainDifference; i--) {
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this.store.deleteGraph(oldChain[i].hash);
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}
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//if they didn't differ in the length of the old chain, must be one after
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return oldChain.length;
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for (let i = chainDifference; i < newChain.length; ++i) {
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addBlockMetadata(this, newChain[i]);
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}
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//fix balance
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this.balances = verifyResult.balances;
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return {
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result: true,
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chainDifference: chainDifference,
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oldChain: oldChain
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};
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}
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}
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