// Bitcoin Dev Kit
// Written in 2020 by Alekos Filini <alekos.filini@gmail.com>
//
// Copyright (c) 2020-2021 Bitcoin Dev Kit Developers
//
// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
// You may not use this file except in accordance with one or both of these
// licenses.
//! Transaction builder
//!
//! ## Example
//!
//! ```
//! # use std::str::FromStr;
//! # use bitcoin::*;
//! # use bdk::*;
//! # use bdk::wallet::tx_builder::CreateTx;
//! # let to_address = Address::from_str("2N4eQYCbKUHCCTUjBJeHcJp9ok6J2GZsTDt").unwrap();
//! # let wallet = doctest_wallet!();
//! // create a TxBuilder from a wallet
//! let mut tx_builder = wallet.build_tx();
//!
//! tx_builder
//! // Create a transaction with one output to `to_address` of 50_000 satoshi
//! .add_recipient(to_address.script_pubkey(), 50_000)
//! // With a custom fee rate of 5.0 satoshi/vbyte
//! .fee_rate(FeeRate::from_sat_per_vb(5.0))
//! // Only spend non-change outputs
//! .do_not_spend_change()
//! // Turn on RBF signaling
//! .enable_rbf();
//! let (psbt, tx_details) = tx_builder.finish()?;
//! # Ok::<(), bdk::Error>(())
//! ```
use std::collections::BTreeMap;
use std::collections::HashSet;
use std::default::Default;
use std::marker::PhantomData;
use bitcoin::util::psbt::{self, PartiallySignedTransaction as Psbt};
use bitcoin::{LockTime, OutPoint, Script, Sequence, Transaction};
use super::coin_selection::{CoinSelectionAlgorithm, DefaultCoinSelectionAlgorithm};
use crate::{database::BatchDatabase, Error, Utxo, Wallet};
use crate::{
types::{FeeRate, KeychainKind, LocalUtxo, WeightedUtxo},
TransactionDetails,
};
/// Context in which the [`TxBuilder`] is valid
pub trait TxBuilderContext: std::fmt::Debug + Default + Clone {}
/// Marker type to indicate the [`TxBuilder`] is being used to create a new transaction (as opposed
/// to bumping the fee of an existing one).
#[derive(Debug, Default, Clone)]
pub struct CreateTx;
impl TxBuilderContext for CreateTx {}
/// Marker type to indicate the [`TxBuilder`] is being used to bump the fee of an existing transaction.
#[derive(Debug, Default, Clone)]
pub struct BumpFee;
impl TxBuilderContext for BumpFee {}
/// A transaction builder
///
/// A `TxBuilder` is created by calling [`build_tx`] or [`build_fee_bump`] on a wallet. After
/// assigning it, you set options on it until finally calling [`finish`] to consume the builder and
/// generate the transaction.
///
/// Each option setting method on `TxBuilder` takes and returns `&mut self` so you can chain calls
/// as in the following example:
///
/// ```
/// # use bdk::*;
/// # use bdk::wallet::tx_builder::*;
/// # use bitcoin::*;
/// # use core::str::FromStr;
/// # let wallet = doctest_wallet!();
/// # let addr1 = Address::from_str("2N4eQYCbKUHCCTUjBJeHcJp9ok6J2GZsTDt").unwrap();
/// # let addr2 = addr1.clone();
/// // chaining
/// let (psbt1, details) = {
/// let mut builder = wallet.build_tx();
/// builder
/// .ordering(TxOrdering::Untouched)
/// .add_recipient(addr1.script_pubkey(), 50_000)
/// .add_recipient(addr2.script_pubkey(), 50_000);
/// builder.finish()?
/// };
///
/// // non-chaining
/// let (psbt2, details) = {
/// let mut builder = wallet.build_tx();
/// builder.ordering(TxOrdering::Untouched);
/// for addr in &[addr1, addr2] {
/// builder.add_recipient(addr.script_pubkey(), 50_000);
/// }
/// builder.finish()?
/// };
///
/// assert_eq!(psbt1.unsigned_tx.output[..2], psbt2.unsigned_tx.output[..2]);
/// # Ok::<(), bdk::Error>(())
/// ```
///
/// At the moment [`coin_selection`] is an exception to the rule as it consumes `self`.
/// This means it is usually best to call [`coin_selection`] on the return value of `build_tx` before assigning it.
///
/// For further examples see [this module](super::tx_builder)'s documentation;
///
/// [`build_tx`]: Wallet::build_tx
/// [`build_fee_bump`]: Wallet::build_fee_bump
/// [`finish`]: Self::finish
/// [`coin_selection`]: Self::coin_selection
#[derive(Debug)]
pub struct TxBuilder<'a, D, Cs, Ctx> {
pub(crate) wallet: &'a Wallet<D>,
pub(crate) params: TxParams,
pub(crate) coin_selection: Cs,
pub(crate) phantom: PhantomData<Ctx>,
}
/// The parameters for transaction creation sans coin selection algorithm.
//TODO: TxParams should eventually be exposed publicly.
#[derive(Default, Debug, Clone)]
pub(crate) struct TxParams {
pub(crate) recipients: Vec<(Script, u64)>,
pub(crate) drain_wallet: bool,
pub(crate) drain_to: Option<Script>,
pub(crate) fee_policy: Option<FeePolicy>,
pub(crate) internal_policy_path: Option<BTreeMap<String, Vec<usize>>>,
pub(crate) external_policy_path: Option<BTreeMap<String, Vec<usize>>>,
pub(crate) utxos: Vec<WeightedUtxo>,
pub(crate) unspendable: HashSet<OutPoint>,
pub(crate) manually_selected_only: bool,
pub(crate) sighash: Option<psbt::PsbtSighashType>,
pub(crate) ordering: TxOrdering,
pub(crate) locktime: Option<LockTime>,
pub(crate) rbf: Option<RbfValue>,
pub(crate) version: Option<Version>,
pub(crate) change_policy: ChangeSpendPolicy,
pub(crate) only_witness_utxo: bool,
pub(crate) add_global_xpubs: bool,
pub(crate) include_output_redeem_witness_script: bool,
pub(crate) bumping_fee: Option<PreviousFee>,
pub(crate) current_height: Option<LockTime>,
pub(crate) allow_dust: bool,
}
#[derive(Clone, Copy, Debug)]
pub(crate) struct PreviousFee {
pub absolute: u64,
pub rate: f32,
}
#[derive(Debug, Clone, Copy)]
pub(crate) enum FeePolicy {
FeeRate(FeeRate),
FeeAmount(u64),
}
impl std::default::Default for FeePolicy {
fn default() -> Self {
FeePolicy::FeeRate(FeeRate::default_min_relay_fee())
}
}
impl<'a, Cs: Clone, Ctx, D> Clone for TxBuilder<'a, D, Cs, Ctx> {
fn clone(&self) -> Self {
TxBuilder {
wallet: self.wallet,
params: self.params.clone(),
coin_selection: self.coin_selection.clone(),
phantom: PhantomData,
}
}
}
// methods supported by both contexts, for any CoinSelectionAlgorithm
impl<'a, D: BatchDatabase, Cs: CoinSelectionAlgorithm<D>, Ctx: TxBuilderContext>
TxBuilder<'a, D, Cs, Ctx>
{
/// Set a custom fee rate
pub fn fee_rate(&mut self, fee_rate: FeeRate) -> &mut Self {
self.params.fee_policy = Some(FeePolicy::FeeRate(fee_rate));
self
}
/// Set an absolute fee
pub fn fee_absolute(&mut self, fee_amount: u64) -> &mut Self {
self.params.fee_policy = Some(FeePolicy::FeeAmount(fee_amount));
self
}
/// Set the policy path to use while creating the transaction for a given keychain.
///
/// This method accepts a map where the key is the policy node id (see
/// [`Policy::id`](crate::descriptor::Policy::id)) and the value is the list of the indexes of
/// the items that are intended to be satisfied from the policy node (see
/// [`SatisfiableItem::Thresh::items`](crate::descriptor::policy::SatisfiableItem::Thresh::items)).
///
/// ## Example
///
/// An example of when the policy path is needed is the following descriptor:
/// `wsh(thresh(2,pk(A),sj:and_v(v:pk(B),n:older(6)),snj:and_v(v:pk(C),after(630000))))`,
/// derived from the miniscript policy `thresh(2,pk(A),and(pk(B),older(6)),and(pk(C),after(630000)))`.
/// It declares three descriptor fragments, and at the top level it uses `thresh()` to
/// ensure that at least two of them are satisfied. The individual fragments are:
///
/// 1. `pk(A)`
/// 2. `and(pk(B),older(6))`
/// 3. `and(pk(C),after(630000))`
///
/// When those conditions are combined in pairs, it's clear that the transaction needs to be created
/// differently depending on how the user intends to satisfy the policy afterwards:
///
/// * If fragments `1` and `2` are used, the transaction will need to use a specific
/// `n_sequence` in order to spend an `OP_CSV` branch.
/// * If fragments `1` and `3` are used, the transaction will need to use a specific `locktime`
/// in order to spend an `OP_CLTV` branch.
/// * If fragments `2` and `3` are used, the transaction will need both.
///
/// When the spending policy is represented as a tree (see
/// [`Wallet::policies`](super::Wallet::policies)), every node
/// is assigned a unique identifier that can be used in the policy path to specify which of
/// the node's children the user intends to satisfy: for instance, assuming the `thresh()`
/// root node of this example has an id of `aabbccdd`, the policy path map would look like:
///
/// `{ "aabbccdd" => [0, 1] }`
///
/// where the key is the node's id, and the value is a list of the children that should be
/// used, in no particular order.
///
/// If a particularly complex descriptor has multiple ambiguous thresholds in its structure,
/// multiple entries can be added to the map, one for each node that requires an explicit path.
///
/// ```
/// # use std::str::FromStr;
/// # use std::collections::BTreeMap;
/// # use bitcoin::*;
/// # use bdk::*;
/// # let to_address = Address::from_str("2N4eQYCbKUHCCTUjBJeHcJp9ok6J2GZsTDt").unwrap();
/// # let wallet = doctest_wallet!();
/// let mut path = BTreeMap::new();
/// path.insert("aabbccdd".to_string(), vec![0, 1]);
///
/// let builder = wallet
/// .build_tx()
/// .add_recipient(to_address.script_pubkey(), 50_000)
/// .policy_path(path, KeychainKind::External);
///
/// # Ok::<(), bdk::Error>(())
/// ```
pub fn policy_path(
&mut self,
policy_path: BTreeMap<String, Vec<usize>>,
keychain: KeychainKind,
) -> &mut Self {
let to_update = match keychain {
KeychainKind::Internal => &mut self.params.internal_policy_path,
KeychainKind::External => &mut self.params.external_policy_path,
};
*to_update = Some(policy_path);
self
}
/// Add the list of outpoints to the internal list of UTXOs that **must** be spent.
///
/// If an error occurs while adding any of the UTXOs then none of them are added and the error is returned.
///
/// These have priority over the "unspendable" utxos, meaning that if a utxo is present both in
/// the "utxos" and the "unspendable" list, it will be spent.
pub fn add_utxos(&mut self, outpoints: &[OutPoint]) -> Result<&mut Self, Error> {
let utxos = outpoints
.iter()
.map(|outpoint| self.wallet.get_utxo(*outpoint)?.ok_or(Error::UnknownUtxo))
.collect::<Result<Vec<_>, _>>()?;
for utxo in utxos {
let descriptor = self.wallet.get_descriptor_for_keychain(utxo.keychain);
let satisfaction_weight = descriptor.max_satisfaction_weight().unwrap();
self.params.utxos.push(WeightedUtxo {
satisfaction_weight,
utxo: Utxo::Local(utxo),
});
}
Ok(self)
}
/// Add a utxo to the internal list of utxos that **must** be spent
///
/// These have priority over the "unspendable" utxos, meaning that if a utxo is present both in
/// the "utxos" and the "unspendable" list, it will be spent.
pub fn add_utxo(&mut self, outpoint: OutPoint) -> Result<&mut Self, Error> {
self.add_utxos(&[outpoint])
}
/// Add a foreign UTXO i.e. a UTXO not owned by this wallet.
///
/// At a minimum to add a foreign UTXO we need:
///
/// 1. `outpoint`: To add it to the raw transaction.
/// 2. `psbt_input`: To know the value.
/// 3. `satisfaction_weight`: To know how much weight/vbytes the input will add to the transaction for fee calculation.
///
/// There are several security concerns about adding foreign UTXOs that application
/// developers should consider. First, how do you know the value of the input is correct? If a
/// `non_witness_utxo` is provided in the `psbt_input` then this method implicitly verifies the
/// value by checking it against the transaction. If only a `witness_utxo` is provided then this
/// method doesn't verify the value but just takes it as a given -- it is up to you to check
/// that whoever sent you the `input_psbt` was not lying!
///
/// Secondly, you must somehow provide `satisfaction_weight` of the input. Depending on your
/// application it may be important that this be known precisely. If not, a malicious
/// counterparty may fool you into putting in a value that is too low, giving the transaction a
/// lower than expected feerate. They could also fool you into putting a value that is too high
/// causing you to pay a fee that is too high. The party who is broadcasting the transaction can
/// of course check the real input weight matches the expected weight prior to broadcasting.
///
/// To guarantee the `satisfaction_weight` is correct, you can require the party providing the
/// `psbt_input` provide a miniscript descriptor for the input so you can check it against the
/// `script_pubkey` and then ask it for the [`max_satisfaction_weight`].
///
/// This is an **EXPERIMENTAL** feature, API and other major changes are expected.
///
/// # Errors
///
/// This method returns errors in the following circumstances:
///
/// 1. The `psbt_input` does not contain a `witness_utxo` or `non_witness_utxo`.
/// 2. The data in `non_witness_utxo` does not match what is in `outpoint`.
///
/// Note unless you set [`only_witness_utxo`] any non-taproot `psbt_input` you pass to this
/// method must have `non_witness_utxo` set otherwise you will get an error when [`finish`]
/// is called.
///
/// [`only_witness_utxo`]: Self::only_witness_utxo
/// [`finish`]: Self::finish
/// [`max_satisfaction_weight`]: miniscript::Descriptor::max_satisfaction_weight
pub fn add_foreign_utxo(
&mut self,
outpoint: OutPoint,
psbt_input: psbt::Input,
satisfaction_weight: usize,
) -> Result<&mut Self, Error> {
if psbt_input.witness_utxo.is_none() {
match psbt_input.non_witness_utxo.as_ref() {
Some(tx) => {
if tx.txid() != outpoint.txid {
return Err(Error::Generic(
"Foreign utxo outpoint does not match PSBT input".into(),
));
}
if tx.output.len() <= outpoint.vout as usize {
return Err(Error::InvalidOutpoint(outpoint));
}
}
None => {
return Err(Error::Generic(
"Foreign utxo missing witness_utxo or non_witness_utxo".into(),
))
}
}
}
self.params.utxos.push(WeightedUtxo {
satisfaction_weight,
utxo: Utxo::Foreign {
outpoint,
psbt_input: Box::new(psbt_input),
},
});
Ok(self)
}
/// Only spend utxos added by [`add_utxo`].
///
/// The wallet will **not** add additional utxos to the transaction even if they are needed to
/// make the transaction valid.
///
/// [`add_utxo`]: Self::add_utxo
pub fn manually_selected_only(&mut self) -> &mut Self {
self.params.manually_selected_only = true;
self
}
/// Replace the internal list of unspendable utxos with a new list
///
/// It's important to note that the "must-be-spent" utxos added with [`TxBuilder::add_utxo`]
/// have priority over these. See the docs of the two linked methods for more details.
pub fn unspendable(&mut self, unspendable: Vec<OutPoint>) -> &mut Self {
self.params.unspendable = unspendable.into_iter().collect();
self
}
/// Add a utxo to the internal list of unspendable utxos
///
/// It's important to note that the "must-be-spent" utxos added with [`TxBuilder::add_utxo`]
/// have priority over this. See the docs of the two linked methods for more details.
pub fn add_unspendable(&mut self, unspendable: OutPoint) -> &mut Self {
self.params.unspendable.insert(unspendable);
self
}
/// Sign with a specific sig hash
///
/// **Use this option very carefully**
pub fn sighash(&mut self, sighash: psbt::PsbtSighashType) -> &mut Self {
self.params.sighash = Some(sighash);
self
}
/// Choose the ordering for inputs and outputs of the transaction
pub fn ordering(&mut self, ordering: TxOrdering) -> &mut Self {
self.params.ordering = ordering;
self
}
/// Use a specific nLockTime while creating the transaction
///
/// This can cause conflicts if the wallet's descriptors contain an "after" (OP_CLTV) operator.
pub fn nlocktime(&mut self, locktime: LockTime) -> &mut Self {
self.params.locktime = Some(locktime);
self
}
/// Build a transaction with a specific version
///
/// The `version` should always be greater than `0` and greater than `1` if the wallet's
/// descriptors contain an "older" (OP_CSV) operator.
pub fn version(&mut self, version: i32) -> &mut Self {
self.params.version = Some(Version(version));
self
}
/// Do not spend change outputs
///
/// This effectively adds all the change outputs to the "unspendable" list. See
/// [`TxBuilder::unspendable`].
pub fn do_not_spend_change(&mut self) -> &mut Self {
self.params.change_policy = ChangeSpendPolicy::ChangeForbidden;
self
}
/// Only spend change outputs
///
/// This effectively adds all the non-change outputs to the "unspendable" list. See
/// [`TxBuilder::unspendable`].
pub fn only_spend_change(&mut self) -> &mut Self {
self.params.change_policy = ChangeSpendPolicy::OnlyChange;
self
}
/// Set a specific [`ChangeSpendPolicy`]. See [`TxBuilder::do_not_spend_change`] and
/// [`TxBuilder::only_spend_change`] for some shortcuts.
pub fn change_policy(&mut self, change_policy: ChangeSpendPolicy) -> &mut Self {
self.params.change_policy = change_policy;
self
}
/// Only Fill-in the [`psbt::Input::witness_utxo`](bitcoin::util::psbt::Input::witness_utxo) field when spending from
/// SegWit descriptors.
///
/// This reduces the size of the PSBT, but some signers might reject them due to the lack of
/// the `non_witness_utxo`.
pub fn only_witness_utxo(&mut self) -> &mut Self {
self.params.only_witness_utxo = true;
self
}
/// Fill-in the [`psbt::Output::redeem_script`](bitcoin::util::psbt::Output::redeem_script) and
/// [`psbt::Output::witness_script`](bitcoin::util::psbt::Output::witness_script) fields.
///
/// This is useful for signers which always require it, like ColdCard hardware wallets.
pub fn include_output_redeem_witness_script(&mut self) -> &mut Self {
self.params.include_output_redeem_witness_script = true;
self
}
/// Fill-in the `PSBT_GLOBAL_XPUB` field with the extended keys contained in both the external
/// and internal descriptors
///
/// This is useful for offline signers that take part to a multisig. Some hardware wallets like
/// BitBox and ColdCard are known to require this.
pub fn add_global_xpubs(&mut self) -> &mut Self {
self.params.add_global_xpubs = true;
self
}
/// Spend all the available inputs. This respects filters like [`TxBuilder::unspendable`] and the change policy.
pub fn drain_wallet(&mut self) -> &mut Self {
self.params.drain_wallet = true;
self
}
/// Choose the coin selection algorithm
///
/// Overrides the [`DefaultCoinSelectionAlgorithm`](super::coin_selection::DefaultCoinSelectionAlgorithm).
///
/// Note that this function consumes the builder and returns it so it is usually best to put this as the first call on the builder.
pub fn coin_selection<P: CoinSelectionAlgorithm<D>>(
self,
coin_selection: P,
) -> TxBuilder<'a, D, P, Ctx> {
TxBuilder {
wallet: self.wallet,
params: self.params,
coin_selection,
phantom: PhantomData,
}
}
/// Finish building the transaction.
///
/// Returns the [`BIP174`] "PSBT" and summary details about the transaction.
///
/// [`BIP174`]: https://github.com/bitcoin/bips/blob/master/bip-0174.mediawiki
pub fn finish(self) -> Result<(Psbt, TransactionDetails), Error> {
self.wallet.create_tx(self.coin_selection, self.params)
}
/// Enable signaling RBF
///
/// This will use the default nSequence value of `0xFFFFFFFD`.
pub fn enable_rbf(&mut self) -> &mut Self {
self.params.rbf = Some(RbfValue::Default);
self
}
/// Enable signaling RBF with a specific nSequence value
///
/// This can cause conflicts if the wallet's descriptors contain an "older" (OP_CSV) operator
/// and the given `nsequence` is lower than the CSV value.
///
/// If the `nsequence` is higher than `0xFFFFFFFD` an error will be thrown, since it would not
/// be a valid nSequence to signal RBF.
pub fn enable_rbf_with_sequence(&mut self, nsequence: Sequence) -> &mut Self {
self.params.rbf = Some(RbfValue::Value(nsequence));
self
}
/// Set the current blockchain height.
///
/// This will be used to:
/// 1. Set the nLockTime for preventing fee sniping.
/// **Note**: This will be ignored if you manually specify a nlocktime using [`TxBuilder::nlocktime`].
/// 2. Decide whether coinbase outputs are mature or not. If the coinbase outputs are not
/// mature at `current_height`, we ignore them in the coin selection.
/// If you want to create a transaction that spends immature coinbase inputs, manually
/// add them using [`TxBuilder::add_utxos`].
///
/// In both cases, if you don't provide a current height, we use the last sync height.
pub fn current_height(&mut self, height: u32) -> &mut Self {
self.params.current_height = Some(LockTime::from_height(height).expect("Invalid height"));
self
}
/// Set whether or not the dust limit is checked.
///
/// **Note**: by avoiding a dust limit check you may end up with a transaction that is non-standard.
pub fn allow_dust(&mut self, allow_dust: bool) -> &mut Self {
self.params.allow_dust = allow_dust;
self
}
}
impl<'a, D: BatchDatabase, Cs: CoinSelectionAlgorithm<D>> TxBuilder<'a, D, Cs, CreateTx> {
/// Replace the recipients already added with a new list
pub fn set_recipients(&mut self, recipients: Vec<(Script, u64)>) -> &mut Self {
self.params.recipients = recipients;
self
}
/// Add a recipient to the internal list
pub fn add_recipient(&mut self, script_pubkey: Script, amount: u64) -> &mut Self {
self.params.recipients.push((script_pubkey, amount));
self
}
/// Add data as an output, using OP_RETURN
pub fn add_data(&mut self, data: &[u8]) -> &mut Self {
let script = Script::new_op_return(data);
self.add_recipient(script, 0u64);
self
}
/// Sets the address to *drain* excess coins to.
///
/// Usually, when there are excess coins they are sent to a change address generated by the
/// wallet. This option replaces the usual change address with an arbitrary `script_pubkey` of
/// your choosing. Just as with a change output, if the drain output is not needed (the excess
/// coins are too small) it will not be included in the resulting transaction. The only
/// difference is that it is valid to use `drain_to` without setting any ordinary recipients
/// with [`add_recipient`] (but it is perfectly fine to add recipients as well).
///
/// If you choose not to set any recipients, you should either provide the utxos that the
/// transaction should spend via [`add_utxos`], or set [`drain_wallet`] to spend all of them.
///
/// When bumping the fees of a transaction made with this option, you probably want to
/// use [`allow_shrinking`] to allow this output to be reduced to pay for the extra fees.
///
/// # Example
///
/// `drain_to` is very useful for draining all the coins in a wallet with [`drain_wallet`] to a
/// single address.
///
/// ```
/// # use std::str::FromStr;
/// # use bitcoin::*;
/// # use bdk::*;
/// # use bdk::wallet::tx_builder::CreateTx;
/// # let to_address = Address::from_str("2N4eQYCbKUHCCTUjBJeHcJp9ok6J2GZsTDt").unwrap();
/// # let wallet = doctest_wallet!();
/// let mut tx_builder = wallet.build_tx();
///
/// tx_builder
/// // Spend all outputs in this wallet.
/// .drain_wallet()
/// // Send the excess (which is all the coins minus the fee) to this address.
/// .drain_to(to_address.script_pubkey())
/// .fee_rate(FeeRate::from_sat_per_vb(5.0))
/// .enable_rbf();
/// let (psbt, tx_details) = tx_builder.finish()?;
/// # Ok::<(), bdk::Error>(())
/// ```
///
/// [`allow_shrinking`]: Self::allow_shrinking
/// [`add_recipient`]: Self::add_recipient
/// [`add_utxos`]: Self::add_utxos
/// [`drain_wallet`]: Self::drain_wallet
pub fn drain_to(&mut self, script_pubkey: Script) -> &mut Self {
self.params.drain_to = Some(script_pubkey);
self
}
}
// methods supported only by bump_fee
impl<'a, D: BatchDatabase> TxBuilder<'a, D, DefaultCoinSelectionAlgorithm, BumpFee> {
/// Explicitly tells the wallet that it is allowed to reduce the amount of the output matching this
/// `script_pubkey` in order to bump the transaction fee. Without specifying this the wallet
/// will attempt to find a change output to shrink instead.
///
/// **Note** that the output may shrink to below the dust limit and therefore be removed. If it is
/// preserved then it is currently not guaranteed to be in the same position as it was
/// originally.
///
/// Returns an `Err` if `script_pubkey` can't be found among the recipients of the
/// transaction we are bumping.
pub fn allow_shrinking(&mut self, script_pubkey: Script) -> Result<&mut Self, Error> {
match self
.params
.recipients
.iter()
.position(|(recipient_script, _)| *recipient_script == script_pubkey)
{
Some(position) => {
self.params.recipients.remove(position);
self.params.drain_to = Some(script_pubkey);
Ok(self)
}
None => Err(Error::Generic(format!(
"{} was not in the original transaction",
script_pubkey
))),
}
}
}
/// Ordering of the transaction's inputs and outputs
#[derive(Debug, Ord, PartialOrd, Eq, PartialEq, Hash, Clone, Copy)]
pub enum TxOrdering {
/// Randomized (default)
Shuffle,
/// Unchanged
Untouched,
/// BIP69 / Lexicographic
Bip69Lexicographic,
}
impl Default for TxOrdering {
fn default() -> Self {
TxOrdering::Shuffle
}
}
impl TxOrdering {
/// Sort transaction inputs and outputs by [`TxOrdering`] variant
pub fn sort_tx(&self, tx: &mut Transaction) {
match self {
TxOrdering::Untouched => {}
TxOrdering::Shuffle => {
use rand::seq::SliceRandom;
#[cfg(test)]
use rand::SeedableRng;
#[cfg(not(test))]
let mut rng = rand::thread_rng();
#[cfg(test)]
let mut rng = rand::rngs::StdRng::seed_from_u64(12345);
tx.output.shuffle(&mut rng);
}
TxOrdering::Bip69Lexicographic => {
tx.input.sort_unstable_by_key(|txin| {
(txin.previous_output.txid, txin.previous_output.vout)
});
tx.output
.sort_unstable_by_key(|txout| (txout.value, txout.script_pubkey.clone()));
}
}
}
}
/// Transaction version
///
/// Has a default value of `1`
#[derive(Debug, Ord, PartialOrd, Eq, PartialEq, Hash, Clone, Copy)]
pub(crate) struct Version(pub(crate) i32);
impl Default for Version {
fn default() -> Self {
Version(1)
}
}
/// RBF nSequence value
///
/// Has a default value of `0xFFFFFFFD`
#[derive(Debug, Ord, PartialOrd, Eq, PartialEq, Hash, Clone, Copy)]
pub(crate) enum RbfValue {
Default,
Value(Sequence),
}
impl RbfValue {
pub(crate) fn get_value(&self) -> Sequence {
match self {
RbfValue::Default => Sequence::ENABLE_RBF_NO_LOCKTIME,
RbfValue::Value(v) => *v,
}
}
}
/// Policy regarding the use of change outputs when creating a transaction
#[derive(Debug, Ord, PartialOrd, Eq, PartialEq, Hash, Clone, Copy)]
pub enum ChangeSpendPolicy {
/// Use both change and non-change outputs (default)
ChangeAllowed,
/// Only use change outputs (see [`TxBuilder::only_spend_change`])
OnlyChange,
/// Only use non-change outputs (see [`TxBuilder::do_not_spend_change`])
ChangeForbidden,
}
impl Default for ChangeSpendPolicy {
fn default() -> Self {
ChangeSpendPolicy::ChangeAllowed
}
}
impl ChangeSpendPolicy {
pub(crate) fn is_satisfied_by(&self, utxo: &LocalUtxo) -> bool {
match self {
ChangeSpendPolicy::ChangeAllowed => true,
ChangeSpendPolicy::OnlyChange => utxo.keychain == KeychainKind::Internal,
ChangeSpendPolicy::ChangeForbidden => utxo.keychain == KeychainKind::External,
}
}
}
#[cfg(test)]
mod test {
const ORDERING_TEST_TX: &str = "0200000003c26f3eb7932f7acddc5ddd26602b77e7516079b03090a16e2c2f54\
85d1fd600f0100000000ffffffffc26f3eb7932f7acddc5ddd26602b77e75160\
79b03090a16e2c2f5485d1fd600f0000000000ffffffff571fb3e02278217852\
dd5d299947e2b7354a639adc32ec1fa7b82cfb5dec530e0500000000ffffffff\
03e80300000000000002aaeee80300000000000001aa200300000000000001ff\
00000000";
macro_rules! ordering_test_tx {
() => {
deserialize::<bitcoin::Transaction>(&Vec::<u8>::from_hex(ORDERING_TEST_TX).unwrap())
.unwrap()
};
}
use bitcoin::consensus::deserialize;
use bitcoin::hashes::hex::FromHex;
use super::*;
#[test]
fn test_output_ordering_default_shuffle() {
assert_eq!(TxOrdering::default(), TxOrdering::Shuffle);
}
#[test]
fn test_output_ordering_untouched() {
let original_tx = ordering_test_tx!();
let mut tx = original_tx.clone();
TxOrdering::Untouched.sort_tx(&mut tx);
assert_eq!(original_tx, tx);
}
#[test]
fn test_output_ordering_shuffle() {
let original_tx = ordering_test_tx!();
let mut tx = original_tx.clone();
TxOrdering::Shuffle.sort_tx(&mut tx);
assert_eq!(original_tx.input, tx.input);
assert_ne!(original_tx.output, tx.output);
}
#[test]
fn test_output_ordering_bip69() {
use std::str::FromStr;
let original_tx = ordering_test_tx!();
let mut tx = original_tx;
TxOrdering::Bip69Lexicographic.sort_tx(&mut tx);
assert_eq!(
tx.input[0].previous_output,
bitcoin::OutPoint::from_str(
"0e53ec5dfb2cb8a71fec32dc9a634a35b7e24799295ddd5278217822e0b31f57:5"
)
.unwrap()
);
assert_eq!(
tx.input[1].previous_output,
bitcoin::OutPoint::from_str(
"0f60fdd185542f2c6ea19030b0796051e7772b6026dd5ddccd7a2f93b73e6fc2:0"
)
.unwrap()
);
assert_eq!(
tx.input[2].previous_output,
bitcoin::OutPoint::from_str(
"0f60fdd185542f2c6ea19030b0796051e7772b6026dd5ddccd7a2f93b73e6fc2:1"
)
.unwrap()
);
assert_eq!(tx.output[0].value, 800);
assert_eq!(tx.output[1].script_pubkey, From::from(vec![0xAA]));
assert_eq!(tx.output[2].script_pubkey, From::from(vec![0xAA, 0xEE]));
}
fn get_test_utxos() -> Vec<LocalUtxo> {
use bitcoin::hashes::Hash;
vec![
LocalUtxo {
outpoint: OutPoint {
txid: bitcoin::Txid::from_inner([0; 32]),
vout: 0,
},
txout: Default::default(),
keychain: KeychainKind::External,
is_spent: false,
},
LocalUtxo {
outpoint: OutPoint {
txid: bitcoin::Txid::from_inner([0; 32]),
vout: 1,
},
txout: Default::default(),
keychain: KeychainKind::Internal,
is_spent: false,
},
]
}
#[test]
fn test_change_spend_policy_default() {
let change_spend_policy = ChangeSpendPolicy::default();
let filtered = get_test_utxos()
.into_iter()
.filter(|u| change_spend_policy.is_satisfied_by(u))
.count();
assert_eq!(filtered, 2);
}
#[test]
fn test_change_spend_policy_no_internal() {
let change_spend_policy = ChangeSpendPolicy::ChangeForbidden;
let filtered = get_test_utxos()
.into_iter()
.filter(|u| change_spend_policy.is_satisfied_by(u))
.collect::<Vec<_>>();
assert_eq!(filtered.len(), 1);
assert_eq!(filtered[0].keychain, KeychainKind::External);
}
#[test]
fn test_change_spend_policy_only_internal() {
let change_spend_policy = ChangeSpendPolicy::OnlyChange;
let filtered = get_test_utxos()
.into_iter()
.filter(|u| change_spend_policy.is_satisfied_by(u))
.collect::<Vec<_>>();
assert_eq!(filtered.len(), 1);
assert_eq!(filtered[0].keychain, KeychainKind::Internal);
}
#[test]
fn test_default_tx_version_1() {
let version = Version::default();
assert_eq!(version.0, 1);
}
}