bitcoinjs-lib
Version:
Client-side Bitcoin JavaScript library
169 lines (168 loc) • 6.17 kB
JavaScript
import * as varuint from 'varuint-bitcoin';
import * as bscript from '../script.js';
import { Transaction } from '../transaction.js';
import { hash160 } from '../crypto.js';
import * as payments from '../payments/index.js';
import * as tools from 'uint8array-tools';
/**
* Checks if a given payment factory can generate a payment script from a given script.
* @param payment The payment factory to check.
* @returns A function that takes a script and returns a boolean indicating whether the payment factory can generate a payment script from the script.
*/
function isPaymentFactory(payment) {
return script => {
try {
payment({ output: script });
return true;
} catch (err) {
return false;
}
};
}
export const isP2MS = isPaymentFactory(payments.p2ms);
export const isP2PK = isPaymentFactory(payments.p2pk);
export const isP2PKH = isPaymentFactory(payments.p2pkh);
export const isP2WPKH = isPaymentFactory(payments.p2wpkh);
export const isP2WSHScript = isPaymentFactory(payments.p2wsh);
export const isP2SHScript = isPaymentFactory(payments.p2sh);
export const isP2TR = isPaymentFactory(payments.p2tr);
/**
* Converts a witness stack to a script witness.
* @param witness The witness stack to convert.
* @returns The script witness as a Buffer.
*/
export function witnessStackToScriptWitness(witness) {
let buffer = new Uint8Array(0);
function writeSlice(slice) {
buffer = tools.concat([buffer, slice]);
}
function writeVarInt(i) {
const currentLen = buffer.length;
const varintLen = varuint.encodingLength(i);
buffer = tools.concat([buffer, new Uint8Array(varintLen)]);
varuint.encode(i, buffer, currentLen);
}
function writeVarSlice(slice) {
writeVarInt(slice.length);
writeSlice(slice);
}
function writeVector(vector) {
writeVarInt(vector.length);
vector.forEach(writeVarSlice);
}
writeVector(witness);
return buffer;
}
/**
* Finds the position of a public key in a script.
* @param pubkey The public key to search for.
* @param script The script to search in.
* @returns The index of the public key in the script, or -1 if not found.
* @throws {Error} If there is an unknown script error.
*/
export function pubkeyPositionInScript(pubkey, script) {
const pubkeyHash = hash160(pubkey);
const pubkeyXOnly = pubkey.slice(1, 33); // slice before calling?
const decompiled = bscript.decompile(script);
if (decompiled === null) throw new Error('Unknown script error');
return decompiled.findIndex(element => {
if (typeof element === 'number') return false;
return (
tools.compare(pubkey, element) === 0 ||
tools.compare(pubkeyHash, element) === 0 ||
tools.compare(pubkeyXOnly, element) === 0
);
});
}
/**
* Checks if a public key is present in a script.
* @param pubkey The public key to check.
* @param script The script to search in.
* @returns A boolean indicating whether the public key is present in the script.
*/
export function pubkeyInScript(pubkey, script) {
return pubkeyPositionInScript(pubkey, script) !== -1;
}
/**
* Checks if an input contains a signature for a specific action.
* @param input - The input to check.
* @param action - The action to check for.
* @returns A boolean indicating whether the input contains a signature for the specified action.
*/
export function checkInputForSig(input, action) {
const pSigs = extractPartialSigs(input);
return pSigs.some(pSig =>
signatureBlocksAction(pSig, bscript.signature.decode, action),
);
}
/**
* Determines if a given action is allowed for a signature block.
* @param signature - The signature block.
* @param signatureDecodeFn - The function used to decode the signature.
* @param action - The action to be checked.
* @returns True if the action is allowed, false otherwise.
*/
export function signatureBlocksAction(signature, signatureDecodeFn, action) {
const { hashType } = signatureDecodeFn(signature);
const whitelist = [];
const isAnyoneCanPay = hashType & Transaction.SIGHASH_ANYONECANPAY;
if (isAnyoneCanPay) whitelist.push('addInput');
const hashMod = hashType & 0x1f;
switch (hashMod) {
case Transaction.SIGHASH_ALL:
break;
case Transaction.SIGHASH_SINGLE:
case Transaction.SIGHASH_NONE:
whitelist.push('addOutput');
whitelist.push('setInputSequence');
break;
}
if (whitelist.indexOf(action) === -1) {
return true;
}
return false;
}
/**
* Extracts the signatures from a PsbtInput object.
* If the input has partial signatures, it returns an array of the signatures.
* If the input does not have partial signatures, it checks if it has a finalScriptSig or finalScriptWitness.
* If it does, it extracts the signatures from the final scripts and returns them.
* If none of the above conditions are met, it returns an empty array.
*
* @param input - The PsbtInput object from which to extract the signatures.
* @returns An array of signatures extracted from the PsbtInput object.
*/
function extractPartialSigs(input) {
let pSigs = [];
if ((input.partialSig || []).length === 0) {
if (!input.finalScriptSig && !input.finalScriptWitness) return [];
pSigs = getPsigsFromInputFinalScripts(input);
} else {
pSigs = input.partialSig;
}
return pSigs.map(p => p.signature);
}
/**
* Retrieves the partial signatures (Psigs) from the input's final scripts.
* Psigs are extracted from both the final scriptSig and final scriptWitness of the input.
* Only canonical script signatures are considered.
*
* @param input - The PsbtInput object representing the input.
* @returns An array of PartialSig objects containing the extracted Psigs.
*/
function getPsigsFromInputFinalScripts(input) {
const scriptItems = !input.finalScriptSig
? []
: bscript.decompile(input.finalScriptSig) || [];
const witnessItems = !input.finalScriptWitness
? []
: bscript.decompile(input.finalScriptWitness) || [];
return scriptItems
.concat(witnessItems)
.filter(item => {
return (
item instanceof Uint8Array && bscript.isCanonicalScriptSignature(item)
);
})
.map(sig => ({ signature: sig }));
}