Commit js, ts, and definitions in separate folders

src/block.js

@@ -0,0 +1,190 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+const transaction_1 = require("./transaction");
+const types = require("./types");
+const bcrypto = require("./crypto");
+const bufferutils_1 = require("./bufferutils");
+const fastMerkleRoot = require('merkle-lib/fastRoot');
+const typeforce = require('typeforce');
+const varuint = require('varuint-bitcoin');
+const errorMerkleNoTxes = new TypeError('Cannot compute merkle root for zero transactions');
+const errorWitnessNotSegwit = new TypeError('Cannot compute witness commit for non-segwit block');
+const errorBufferTooSmall = new Error('Buffer too small (< 80 bytes)');
+function txesHaveWitness(transactions) {
+    return transactions !== undefined &&
+        transactions instanceof Array &&
+        transactions[0] &&
+        transactions[0].ins &&
+        transactions[0].ins instanceof Array &&
+        transactions[0].ins[0] &&
+        transactions[0].ins[0].witness &&
+        transactions[0].ins[0].witness instanceof Array &&
+        transactions[0].ins[0].witness.length > 0;
+}
+class Block {
+    constructor() {
+        this.version = 1;
+        this.timestamp = 0;
+        this.bits = 0;
+        this.nonce = 0;
+        this.prevHash = undefined;
+        this.merkleRoot = undefined;
+        this.witnessCommit = undefined;
+        this.transactions = undefined;
+    }
+    static fromBuffer(buffer) {
+        if (buffer.length < 80)
+            throw errorBufferTooSmall;
+        let offset = 0;
+        const readSlice = (n) => {
+            offset += n;
+            return buffer.slice(offset - n, offset);
+        };
+        const readUInt32 = () => {
+            const i = buffer.readUInt32LE(offset);
+            offset += 4;
+            return i;
+        };
+        const readInt32 = () => {
+            const i = buffer.readInt32LE(offset);
+            offset += 4;
+            return i;
+        };
+        const block = new Block();
+        block.version = readInt32();
+        block.prevHash = readSlice(32);
+        block.merkleRoot = readSlice(32);
+        block.timestamp = readUInt32();
+        block.bits = readUInt32();
+        block.nonce = readUInt32();
+        if (buffer.length === 80)
+            return block;
+        const readVarInt = () => {
+            const vi = varuint.decode(buffer, offset);
+            offset += varuint.decode.bytes;
+            return vi;
+        };
+        const readTransaction = () => {
+            const tx = transaction_1.Transaction.fromBuffer(buffer.slice(offset), true);
+            offset += tx.byteLength();
+            return tx;
+        };
+        const nTransactions = readVarInt();
+        block.transactions = [];
+        for (var i = 0; i < nTransactions; ++i) {
+            const tx = readTransaction();
+            block.transactions.push(tx);
+        }
+        // This Block contains a witness commit
+        if (block.hasWitnessCommit()) {
+            // The merkle root for the witness data is in an OP_RETURN output.
+            // There is no rule for the index of the output, so use filter to find it.
+            // The root is prepended with 0xaa21a9ed so check for 0x6a24aa21a9ed
+            // If multiple commits are found, the output with highest index is assumed.
+            let witnessCommits = block.transactions[0].outs
+                .filter(out => out.script.slice(0, 6).equals(Buffer.from('6a24aa21a9ed', 'hex')))
+                .map(out => out.script.slice(6, 38));
+            // Use the commit with the highest output (should only be one though)
+            block.witnessCommit = witnessCommits[witnessCommits.length - 1];
+        }
+        return block;
+    }
+    static fromHex(hex) {
+        return Block.fromBuffer(Buffer.from(hex, 'hex'));
+    }
+    static calculateTarget(bits) {
+        const exponent = ((bits & 0xff000000) >> 24) - 3;
+        const mantissa = bits & 0x007fffff;
+        const target = Buffer.alloc(32, 0);
+        target.writeUIntBE(mantissa, 29 - exponent, 3);
+        return target;
+    }
+    static calculateMerkleRoot(transactions, forWitness) {
+        typeforce([{ getHash: types.Function }], transactions);
+        if (transactions.length === 0)
+            throw errorMerkleNoTxes;
+        if (forWitness && !txesHaveWitness(transactions))
+            throw errorWitnessNotSegwit;
+        const hashes = transactions.map(transaction => transaction.getHash(forWitness));
+        const rootHash = fastMerkleRoot(hashes, bcrypto.hash256);
+        return forWitness
+            ? bcrypto.hash256(Buffer.concat([rootHash, transactions[0].ins[0].witness[0]]))
+            : rootHash;
+    }
+    hasWitnessCommit() {
+        return txesHaveWitness(this.transactions);
+    }
+    byteLength(headersOnly) {
+        if (headersOnly || !this.transactions)
+            return 80;
+        return 80 + varuint.encodingLength(this.transactions.length) +
+            this.transactions.reduce((a, x) => a + x.byteLength(), 0);
+    }
+    getHash() {
+        return bcrypto.hash256(this.toBuffer(true));
+    }
+    getId() {
+        return bufferutils_1.reverseBuffer(this.getHash()).toString('hex');
+    }
+    getUTCDate() {
+        const date = new Date(0); // epoch
+        date.setUTCSeconds(this.timestamp);
+        return date;
+    }
+    // TODO: buffer, offset compatibility
+    toBuffer(headersOnly) {
+        const buffer = Buffer.allocUnsafe(this.byteLength(headersOnly));
+        let offset = 0;
+        const writeSlice = (slice) => {
+            slice.copy(buffer, offset);
+            offset += slice.length;
+        };
+        const writeInt32 = (i) => {
+            buffer.writeInt32LE(i, offset);
+            offset += 4;
+        };
+        const writeUInt32 = (i) => {
+            buffer.writeUInt32LE(i, offset);
+            offset += 4;
+        };
+        writeInt32(this.version);
+        writeSlice(this.prevHash);
+        writeSlice(this.merkleRoot);
+        writeUInt32(this.timestamp);
+        writeUInt32(this.bits);
+        writeUInt32(this.nonce);
+        if (headersOnly || !this.transactions)
+            return buffer;
+        varuint.encode(this.transactions.length, buffer, offset);
+        offset += varuint.encode.bytes;
+        this.transactions.forEach(tx => {
+            const txSize = tx.byteLength(); // TODO: extract from toBuffer?
+            tx.toBuffer(buffer, offset);
+            offset += txSize;
+        });
+        return buffer;
+    }
+    toHex(headersOnly) {
+        return this.toBuffer(headersOnly).toString('hex');
+    }
+    checkMerkleRoot() {
+        if (!this.transactions)
+            throw errorMerkleNoTxes;
+        const actualMerkleRoot = Block.calculateMerkleRoot(this.transactions);
+        return this.merkleRoot.compare(actualMerkleRoot) === 0;
+    }
+    checkWitnessCommit() {
+        if (!this.transactions)
+            throw errorMerkleNoTxes;
+        if (!this.hasWitnessCommit())
+            throw errorWitnessNotSegwit;
+        const actualWitnessCommit = Block.calculateMerkleRoot(this.transactions, true);
+        return this.witnessCommit.compare(actualWitnessCommit) === 0;
+    }
+    checkProofOfWork() {
+        const hash = bufferutils_1.reverseBuffer(this.getHash());
+        const target = Block.calculateTarget(this.bits);
+        return hash.compare(target) <= 0;
+    }
+}
+exports.Block = Block;