All files Tx.ts

94.19% Statements 162/172
63.41% Branches 26/41
82.76% Functions 24/29
96.88% Lines 155/160

Press n or j to go to the next uncovered block, b, p or k for the previous block.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 4721x 1x 1x 1x 1x 1x 1x 1x 1x   1x 1x 1x 1x             1x                 8x 8x 8x   1x                           9x       9x     9x         9x 4x 4x 4x 4x           5x         8x 3x 3x 3x 11x           8x   8x                 13x 13x 13x 7x       13x                 9x 9x 9x 13x         8x                                                     49x                 5x 5x                         5x 5x             127x             127x               49x       56x       5x 5x       5x 5x       5x 5x                                   42x 42x 42x 42x 42x             35x 28x                         1x 1x       1x 1x 1x 1x 1x 1x   1x 1x 1x 1x 1x 1x   1x 1x 1x 1x 1x   1x 1x 1x 1x 5x       1x 1x       33x     33x     33x 33x 32x       33x 33x 38x       33x   33x       9x     9x     9x     9x 9x 10x       9x 9x 13x       9x 9x 10x 10x 24x           9x   9x                               5x 5x     5x                               5x   5x 5x     5x     5x 2x       5x     5x   4x     4x     4x 4x 4x     4x     4x   2x     2x 6x 6x           5x     5x   9x     9x 9x 9x       5x     5x     5x       5x   5x               5x 5x 5x 5x      
import { BufferWriter, StreamReader, varIntBytes } from "@node-lightning/bufio";
import { Hex } from "@node-lightning/bufio";
import { hash256 } from "@node-lightning/crypto";
import { HashByteOrder } from "./HashByteOrder";
import { HashValue } from "./HashValue";
import { LockTime } from "./LockTime";
import { OutPoint } from "./OutPoint";
import { Script } from "./Script";
import { Sequence } from "./Sequence";
import { SizeResult } from "./SizeResult";
import { TxIn } from "./TxIn";
import { TxOut } from "./TxOut";
import { Value } from "./Value";
import { Witness } from "./Witness";
 
/**
 * This class is an immutable Bitcoin transaction. This class is used
 * as a data container from parsed blocks, RPC, or other sources. To use
 * a mutable transaction, you should use `TxBuilder` class.
 */
export class Tx {
    /**
     * Decodes a `Tx` stream similar to Bitcoin Core's DecodeTx method
     * in that it will first try to parse with SegWit markers enabled.
     * If there is an error (such as  with a base transaction with no
     * inputs), then it will try parsing using the legacy method.
     * @param reader
     */
    public static decode(reader: StreamReader): Tx {
        const data = reader.readBytes();
        try {
            return Tx.parse(StreamReader.fromBuffer(data), true);
        } catch (ex) {
            return Tx.parse(StreamReader.fromBuffer(data), false);
        }
    }
 
    /**
     * Parses a transaction from its byte format in a stream. Capable of
     * parsing both legacy and segwit transactions. This method is
     * similar to Bitcoin Core's `UnserializeTransaction` on the
     * `Transaction` type. This method is expected to throw if witness
     * is enabled and we have an ambiguous base transaction (zero inputs).
     * @param reader
     */
    private static parse(reader: StreamReader, allowWitness: boolean): Tx {
        // Read the version
        const version = reader.readUInt32LE();
 
        // Try reading inputs. If this is segwit or a base/dummy, we get
        // an empty array
        let vins: TxIn[] = Tx.parseInputs(reader);
        let vouts: TxOut[];
 
        let flags: number = 0;
 
        // If witness is allowed and we had an empty input array we
        // will try parsing a normal witness transaction. This may throw
        // if this is a base transaction.
        if (allowWitness && vins.length === 0) {
            flags = reader.readUInt8();
            Eif (flags !== 0) {
                vins = Tx.parseInputs(reader);
                vouts = Tx.parseOutputs(reader);
            }
        }
        // Otherwise, we had success reading inputs and can move along
        // and parse the outputs!
        else {
            vouts = Tx.parseOutputs(reader);
        }
 
        // If we have witness and read a flag, then we we need to
        // process the witness for each input.
        if (allowWitness && flags & 1) {
            for (let i = 0; i < vins.length; i++) {
                const items = Number(reader.readVarInt());
                for (let item = 0; item < items; item++) {
                    vins[i].witness.push(Witness.parse(reader));
                }
            }
        }
 
        // Finally read the locktime
        const locktime = LockTime.parse(reader);
 
        return new Tx(version, vins, vouts, locktime);
    }
 
    /**
     * Parses the inputs for a transaction
     * @param reader
     * @returns
     */
    private static parseInputs(reader: StreamReader): TxIn[] {
        const vinLen = Number(reader.readVarInt());
        const inputs: TxIn[] = [];
        for (let idx = 0; idx < vinLen; idx++) {
            inputs.push(
                new TxIn(OutPoint.parse(reader), Script.parse(reader), Sequence.parse(reader)),
            );
        }
        return inputs;
    }
 
    /**
     * Parses the outputs for a transaction
     * @param reader
     * @returns
     */
    private static parseOutputs(reader: StreamReader): TxOut[] {
        const voutLen = Number(reader.readVarInt());
        const outputs: TxOut[] = [];
        for (let idx = 0; idx < voutLen; idx++) {
            outputs.push(new TxOut(
                Value.fromSats(reader.readBigUInt64LE()),
                Script.parse(reader),
            )); // prettier-ignore
        }
        return outputs;
    }
 
    /**
     * Parses a transaction from a buffer that contains the fully
     * serialization transaction bytes.
     * @param buf
     */
    public static fromBuffer(buf: Buffer): Tx {
        return Tx.decode(StreamReader.fromBuffer(buf));
    }
 
    /**
     * Parses a transaction from a hex string containing the fully
     * serialized transaction bytes.
     * @param hex
     */
    public static fromHex(hex: string): Tx {
        return Tx.decode(StreamReader.fromHex(hex));
    }
 
    /**
     * Get the transaction version. The transaction version corresponds
     * to features that are enabled for the transaction such as time
     * locks.
     */
    public get version(): number {
        return this._version;
    }
 
    /**
     * Gets the transaction identifier. The `txId` for both legacy and
     * segwit transaction is the hash256 of
     * `hash256(version||inputs||ouputs||locktime)`.
     */
    public get txId(): HashValue {
        Eif (!this._txId) this._lazyCalc();
        return this._txId;
    }
 
    /**
     * Gets the transaction segwit transaction identifier. For legacy
     * transaction this is the same as the `txId` property. For segwit
     * transaction this is the hash256 of
     * `hash256(version||0x0001||inputs||outputs||witness||locktime)`.
     *
     * This is the same value as the `hash` property in bitcoind RPC
     * results.
     */
    public get witnessTxId(): HashValue {
        Iif (!this._wtxid) this._lazyCalc();
        return this._wtxid;
    }
 
    /**
     * Gets the transaction inputs.
     */
    public get inputs(): TxIn[] {
        return this._inputs;
    }
 
    /**
     * Gets the transaction outputs
     */
    public get outputs(): TxOut[] {
        return this._outputs;
    }
 
    /**
     * Gets the transaction `nLocktime` value that is used to control
     * absolute timelocks.
     */
    public get locktime(): LockTime {
        return this._locktime;
    }
 
    public get isSegWit(): boolean {
        return this._inputs.some(p => p.witness.length > 0);
    }
 
    public get size(): number {
        Iif (!this._sizes) this._lazyCalc();
        return this._sizes.size;
    }
 
    public get vsize(): number {
        Iif (!this._sizes) this._lazyCalc();
        return this._sizes.vsize;
    }
 
    public get weight(): number {
        Iif (!this._sizes) this._lazyCalc();
        return this._sizes.weight;
    }
 
    private _version: number;
    private _txId: HashValue;
    private _wtxid: HashValue;
    private _inputs: TxIn[];
    private _outputs: TxOut[];
    private _locktime: LockTime;
    private _sizes: SizeResult;
 
    public constructor(
        version: number = 2,
        inputs: TxIn[] = [],
        outputs: TxOut[] = [],
        locktime: LockTime = new LockTime(),
        sizes?: SizeResult,
    ) {
        this._version = version;
        this._inputs = inputs;
        this._outputs = outputs;
        this._locktime = locktime;
        this._sizes = sizes;
    }
 
    /**
     * Serializes legacy or segwit transactions into a Buffer
     */
    public serialize(): Buffer {
        if (this.isSegWit) return this._serializeSegWit();
        else return this._serializeLegacy();
    }
 
    public toJSON() {
        return {
            version: this.version,
            inputs: this.inputs.map(vin => vin.toJSON()),
            outputs: this.outputs.map(vout => vout.toJSON()),
            locktime: this.locktime.toJSON(),
        };
    }
 
    public toHex(pretty: boolean = false) {
        Iif (!pretty) return this.serialize().toString("hex");
        else return this._prettyHex();
    }
 
    private _prettyHex(): string {
        const nl = "\n";
        const pad = "    ";
        let s = "";
        s += Hex.uint32LE(this.version) + nl;
        Eif (this.isSegWit) {
            s += "0001" + nl;
        }
        s += Hex.varint(this.inputs.length) + nl;
        for (const vin of this.inputs) {
            s += pad + vin.outpoint.txid.serialize(HashByteOrder.Internal).toString("hex") + nl;
            s += pad + Hex.uint32LE(vin.outpoint.outputIndex) + nl;
            s += pad + vin.scriptSig.serialize().toString("hex") + nl;
            s += pad + Hex.uint32LE(vin.sequence.value) + nl;
        }
        s += Hex.varint(this.outputs.length) + nl;
        for (const vout of this.outputs) {
            s += pad + Hex.uint64LE(vout.value.sats) + nl;
            s += pad + vout.scriptPubKey.serialize().toString("hex");
            s += nl;
        }
        Eif (this.isSegWit) {
            for (const vin of this.inputs) {
                s += Hex.varint(vin.witness.length) + nl;
                for (const w of vin.witness) {
                    s += pad + w.serialize().toString("hex") + nl;
                }
            }
        }
        s += Hex.uint32LE(this.locktime.value);
        return s;
    }
 
    private _serializeLegacy(): Buffer {
        const writer = new BufferWriter();
 
        // version
        writer.writeUInt32LE(this.version);
 
        // inputs
        writer.writeVarInt(this.inputs.length);
        for (const input of this.inputs) {
            writer.writeBytes(input.serialize());
        }
 
        // outputs
        writer.writeVarInt(this.outputs.length);
        for (const output of this.outputs) {
            writer.writeBytes(output.serialize());
        }
 
        // locktime
        writer.writeBytes(this.locktime.serialize());
 
        return writer.toBuffer();
    }
 
    private _serializeSegWit(): Buffer {
        const writer = new BufferWriter();
 
        // version
        writer.writeUInt32LE(this.version);
 
        // write segwit marker and version
        writer.writeBytes(Buffer.from([0x00, 0x01]));
 
        // inputs
        writer.writeVarInt(this.inputs.length);
        for (const input of this.inputs) {
            writer.writeBytes(input.serialize());
        }
 
        // outputs
        writer.writeVarInt(this.outputs.length);
        for (const output of this.outputs) {
            writer.writeBytes(output.serialize());
        }
 
        // witness data
        Eif (this.isSegWit) {
            for (const input of this.inputs) {
                writer.writeVarInt(input.witness.length);
                for (const witness of input.witness) {
                    writer.writeBytes(witness.serialize());
                }
            }
        }
 
        // locktime
        writer.writeBytes(this.locktime.serialize());
 
        return writer.toBuffer();
    }
 
    /**
     * Decodes the txId and hash from the Buffer.
     *
     * For non-segwit transitions, the hash value is the double-sha256 of
     * version|vins|vouts|locktime. The txid is the reverse of the hash.
     *
     * For segwit transactions, the hash value is returned as the wtxid as
     * calculated by the double-sha256 of
     *  version|0x00|0x01|inputs|outputs|witness|locktime. The txId is
     * calculate the same as legacy transactions by performing a double
     * sha256 hash of the data minus segwit data and markers.
     */
    private _calcTxId(): { txId: HashValue; hash: HashValue } {
        const txId: Buffer = hash256(this._serializeLegacy());
        const hash: Buffer = this.isSegWit
            ? hash256(this._serializeSegWit())
            : Buffer.from(txId); // prettier-ignore
        return {
            txId: new HashValue(txId),
            hash: new HashValue(hash),
        };
    }
 
    /**
     * Calculates the size, virtual size, and weight properties from the
     * based on the current inputs and outputs.
     *
     * `size` is the number of raw bytes.
     * `weight` is the number of witness bytes + the number of non-witness
     *   bytes multiplied by four.
     * `vsize` is the weight divided by four.
     */
    private _calcSize(): SizeResult {
        const hasWitness = this.isSegWit;
 
        let standardBytes = 0;
        let witnessBytes = 0;
 
        // version is 4-bytes
        standardBytes += 4;
 
        // witness flags are 2 bytes
        if (hasWitness) {
            witnessBytes += 2;
        }
 
        // number of inputs
        standardBytes += varIntBytes(this.inputs.length);
 
        // add each input
        for (const input of this.inputs) {
            // prev out hash
            standardBytes += 32;
 
            // prev out index
            standardBytes += 4;
 
            // scriptSig length
            const scriptSig = input.scriptSig.serializeCmds();
            standardBytes += varIntBytes(scriptSig.length);
            standardBytes += scriptSig.length;
 
            // sequence, 4-bytes
            standardBytes += 4;
 
            // input witness
            if (hasWitness) {
                // number of witness
                witnessBytes += varIntBytes(input.witness.length);
 
                // for each witness
                for (const witness of input.witness) {
                    witnessBytes += varIntBytes(witness.data.length);
                    witnessBytes += witness.data.length;
                }
            }
        }
 
        // number of outputs
        standardBytes += varIntBytes(this.outputs.length);
 
        // add each output
        for (const output of this.outputs) {
            // value
            standardBytes += 8;
 
            // scriptPubKey length
            const scriptPubKey = output.scriptPubKey.serializeCmds();
            standardBytes += varIntBytes(scriptPubKey.length);
            standardBytes += scriptPubKey.length;
        }
 
        // locktime
        standardBytes += 4;
 
        // size will be the raw length of bytes
        const size = standardBytes + witnessBytes;
 
        // weight is non-witness bytes * 4 + witness bytes
        const weight = standardBytes * 4 + witnessBytes;
 
        // virtual size is weight / 4
        // this is equivalent for non-segwit transactions
        const vsize = Math.ceil(weight / 4);
 
        return {
            size,
            vsize,
            weight,
        };
    }
 
    private _lazyCalc() {
        this._sizes = this._calcSize();
        const ids = this._calcTxId();
        this._txId = ids.txId;
        this._wtxid = ids.hash;
    }
}