12199391122

Committed 06 Dec 2024 01:10PM UTC coverage: 49.807% (-9.1%) from 58.933%

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Merge pull request #9337 from Guayaba221/patch-1

chore: fix typo in ruby.md

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73.3

/input/witnessgen.go

package input

import (
        "fmt"

        "github.com/btcsuite/btcd/txscript"
        "github.com/btcsuite/btcd/wire"
        "github.com/lightningnetwork/lnd/lntypes"
)

// WitnessGenerator represents a function that is able to generate the final
// witness for a particular public key script. Additionally, if required, this
// function will also return the sigScript for spending nested P2SH witness
// outputs. This function acts as an abstraction layer, hiding the details of
// the underlying script.
type WitnessGenerator func(tx *wire.MsgTx, hc *txscript.TxSigHashes,
        inputIndex int) (*Script, error)

// WitnessType determines how an output's witness will be generated. This
// interface can be implemented to be used for custom sweep scripts if the
// pre-defined StandardWitnessType list doesn't provide a suitable one.
type WitnessType interface {
        // String returns a human readable version of the WitnessType.
        String() string

        // WitnessGenerator will return a WitnessGenerator function that an
        // output uses to generate the witness and optionally the sigScript for
        // a sweep transaction.
        WitnessGenerator(signer Signer,
                descriptor *SignDescriptor) WitnessGenerator

        // SizeUpperBound returns the maximum length of the witness of this
        // WitnessType if it would be included in a tx. It also returns if the
        // output itself is a nested p2sh output, if so then we need to take
        // into account the extra sigScript data size.
        SizeUpperBound() (lntypes.WeightUnit, bool, error)

        // AddWeightEstimation adds the estimated size of the witness in bytes
        // to the given weight estimator.
        AddWeightEstimation(e *TxWeightEstimator) error
}

// StandardWitnessType is a numeric representation of standard pre-defined types
// of witness configurations.
type StandardWitnessType uint16

// A compile time check to ensure StandardWitnessType implements the
// WitnessType interface.
var _ WitnessType = (StandardWitnessType)(0)

// NOTE: When adding a new `StandardWitnessType`, also update the `WitnessType`
// protobuf enum and the `allWitnessTypes` map in the `walletrpc` package.
const (
        // CommitmentTimeLock is a witness that allows us to spend our output
        // on our local commitment transaction after a relative lock-time
        // lockout.
        CommitmentTimeLock StandardWitnessType = 0

        // CommitmentNoDelay is a witness that allows us to spend a settled
        // no-delay output immediately on a counterparty's commitment
        // transaction.
        CommitmentNoDelay StandardWitnessType = 1

        // CommitmentRevoke is a witness that allows us to sweep the settled
        // output of a malicious counterparty's who broadcasts a revoked
        // commitment transaction.
        CommitmentRevoke StandardWitnessType = 2

        // HtlcOfferedRevoke is a witness that allows us to sweep an HTLC which
        // we offered to the remote party in the case that they broadcast a
        // revoked commitment state.
        HtlcOfferedRevoke StandardWitnessType = 3

        // HtlcAcceptedRevoke is a witness that allows us to sweep an HTLC
        // output sent to us in the case that the remote party broadcasts a
        // revoked commitment state.
        HtlcAcceptedRevoke StandardWitnessType = 4

        // HtlcOfferedTimeoutSecondLevel is a witness that allows us to sweep
        // an HTLC output that we extended to a party, but was never fulfilled.
        // This HTLC output isn't directly on the commitment transaction, but
        // is the result of a confirmed second-level HTLC transaction. As a
        // result, we can only spend this after a CSV delay.
        HtlcOfferedTimeoutSecondLevel StandardWitnessType = 5

        // HtlcOfferedTimeoutSecondLevelInputConfirmed is a witness that allows
        // us to sweep an HTLC output that we extended to a party, but was
        // never fulfilled. This _is_ the HTLC output directly on our
        // commitment transaction, and the input to the second-level HTLC
        // timeout transaction. It can only be spent after CLTV expiry, and
        // commitment confirmation.
        HtlcOfferedTimeoutSecondLevelInputConfirmed StandardWitnessType = 15

        // HtlcAcceptedSuccessSecondLevel is a witness that allows us to sweep
        // an HTLC output that was offered to us, and for which we have a
        // payment preimage. This HTLC output isn't directly on our commitment
        // transaction, but is the result of confirmed second-level HTLC
        // transaction. As a result, we can only spend this after a CSV delay.
        HtlcAcceptedSuccessSecondLevel StandardWitnessType = 6

        // HtlcAcceptedSuccessSecondLevelInputConfirmed is a witness that
        // allows us to sweep an HTLC output that was offered to us, and for
        // which we have a payment preimage. This _is_ the HTLC output directly
        // on our commitment transaction, and the input to the second-level
        // HTLC success transaction.  It can only be spent after the commitment
        // has confirmed.
        HtlcAcceptedSuccessSecondLevelInputConfirmed StandardWitnessType = 16

        // HtlcOfferedRemoteTimeout is a witness that allows us to sweep an
        // HTLC that we offered to the remote party which lies in the
        // commitment transaction of the remote party. We can spend this output
        // after the absolute CLTV timeout of the HTLC as passed.
        HtlcOfferedRemoteTimeout StandardWitnessType = 7

        // HtlcAcceptedRemoteSuccess is a witness that allows us to sweep an
        // HTLC that was offered to us by the remote party. We use this witness
        // in the case that the remote party goes to chain, and we know the
        // pre-image to the HTLC. We can sweep this without any additional
        // timeout.
        HtlcAcceptedRemoteSuccess StandardWitnessType = 8

        // HtlcSecondLevelRevoke is a witness that allows us to sweep an HTLC
        // from the remote party's commitment transaction in the case that the
        // broadcast a revoked commitment, but then also immediately attempt to
        // go to the second level to claim the HTLC.
        HtlcSecondLevelRevoke StandardWitnessType = 9

        // WitnessKeyHash is a witness type that allows us to spend a regular
        // p2wkh output that's sent to an output which is under complete
        // control of the backing wallet.
        WitnessKeyHash StandardWitnessType = 10

        // NestedWitnessKeyHash is a witness type that allows us to sweep an
        // output that sends to a nested P2SH script that pays to a key solely
        // under our control. The witness generated needs to include the
        NestedWitnessKeyHash StandardWitnessType = 11

        // CommitSpendNoDelayTweakless is similar to the CommitSpendNoDelay
        // type, but it omits the tweak that randomizes the key we need to
        // spend with a channel peer supplied set of randomness.
        CommitSpendNoDelayTweakless StandardWitnessType = 12

        // CommitmentToRemoteConfirmed is a witness that allows us to spend our
        // output on the counterparty's commitment transaction after a
        // confirmation.
        CommitmentToRemoteConfirmed StandardWitnessType = 13

        // CommitmentAnchor is a witness that allows us to spend our anchor on
        // the commitment transaction.
        CommitmentAnchor StandardWitnessType = 14

        // LeaseCommitmentTimeLock is a witness that allows us to spend our
        // output on our local commitment transaction after a relative and
        // absolute lock-time lockout as part of the script enforced lease
        // commitment type.
        LeaseCommitmentTimeLock StandardWitnessType = 17

        // LeaseCommitmentToRemoteConfirmed is a witness that allows us to spend
        // our output on the counterparty's commitment transaction after a
        // confirmation and absolute locktime as part of the script enforced
        // lease commitment type.
        LeaseCommitmentToRemoteConfirmed StandardWitnessType = 18

        // LeaseHtlcOfferedTimeoutSecondLevel is a witness that allows us to
        // sweep an HTLC output that we extended to a party, but was never
        // fulfilled. This HTLC output isn't directly on the commitment
        // transaction, but is the result of a confirmed second-level HTLC
        // transaction. As a result, we can only spend this after a CSV delay
        // and CLTV locktime as part of the script enforced lease commitment
        // type.
        LeaseHtlcOfferedTimeoutSecondLevel StandardWitnessType = 19

        // LeaseHtlcAcceptedSuccessSecondLevel is a witness that allows us to
        // sweep an HTLC output that was offered to us, and for which we have a
        // payment preimage. This HTLC output isn't directly on our commitment
        // transaction, but is the result of confirmed second-level HTLC
        // transaction. As a result, we can only spend this after a CSV delay
        // and CLTV locktime as part of the script enforced lease commitment
        // type.
        LeaseHtlcAcceptedSuccessSecondLevel StandardWitnessType = 20

        // TaprootPubKeySpend is a witness type that allows us to spend a
        // regular p2tr output that's sent to an output which is under complete
        // control of the backing wallet.
        TaprootPubKeySpend StandardWitnessType = 21

        // TaprootLocalCommitSpend is a witness type that allows us to spend
        // our settled local commitment after a CSV delay when we force close
        // the channel.
        TaprootLocalCommitSpend StandardWitnessType = 22

        // TaprootRemoteCommitSpend is a witness type that allows us to spend
        // our settled local commitment after a CSV delay when the remote party
        // has force closed the channel.
        TaprootRemoteCommitSpend StandardWitnessType = 23

        // TaprootAnchorSweepSpend is the witness type we'll use for spending
        // our own anchor output.
        TaprootAnchorSweepSpend StandardWitnessType = 24

        // TaprootHtlcOfferedTimeoutSecondLevel is a witness that allows us to
        // timeout an HTLC we offered to the remote party on our commitment
        // transaction. We use this when we need to go on chain to time out an
        // HTLC.
        TaprootHtlcOfferedTimeoutSecondLevel StandardWitnessType = 25

        // TaprootHtlcAcceptedSuccessSecondLevel is a witness that allows us to
        // sweep an HTLC we accepted on our commitment transaction after we go
        // to the second level on chain.
        TaprootHtlcAcceptedSuccessSecondLevel StandardWitnessType = 26

        // TaprootHtlcSecondLevelRevoke is a witness that allows us to sweep an
        // HTLC on the revoked transaction of the remote party that goes to the
        // second level.
        TaprootHtlcSecondLevelRevoke StandardWitnessType = 27

        // TaprootHtlcAcceptedRevoke is a witness that allows us to sweep an
        // HTLC sent to us by the remote party in the event that they broadcast
        // a revoked state.
        TaprootHtlcAcceptedRevoke StandardWitnessType = 28

        // TaprootHtlcOfferedRevoke is a witness that allows us to sweep an
        // HTLC we offered to the remote party if they broadcast a revoked
        // commitment.
        TaprootHtlcOfferedRevoke StandardWitnessType = 29

        // TaprootHtlcOfferedRemoteTimeout is a witness that allows us to sweep
        // an HTLC we offered to the remote party that lies on the commitment
        // transaction for the remote party. We can spend this output after the
        // absolute CLTV timeout of the HTLC as passed.
        TaprootHtlcOfferedRemoteTimeout StandardWitnessType = 30

        // TaprootHtlcLocalOfferedTimeout is a witness type that allows us to
        // sign the second level HTLC timeout transaction when spending from an
        // HTLC residing on our local commitment transaction.
        //
        // This is used by the sweeper to re-sign inputs if it needs to
        // aggregate several second level HTLCs.
        TaprootHtlcLocalOfferedTimeout StandardWitnessType = 31

        // TaprootHtlcAcceptedRemoteSuccess is a witness that allows us to
        // sweep an HTLC that was offered to us by the remote party for a
        // taproot channels. We use this witness in the case that the remote
        // party goes to chain, and we know the pre-image to the HTLC. We can
        // sweep this without any additional timeout.
        TaprootHtlcAcceptedRemoteSuccess StandardWitnessType = 32

        // TaprootHtlcAcceptedLocalSuccess is a witness type that allows us to
        // sweep the HTLC offered to us on our local commitment transaction.
        // We'll use this when we need to go on chain to sweep the HTLC. In
        // this case, this is the second level HTLC success transaction.
        TaprootHtlcAcceptedLocalSuccess StandardWitnessType = 33

        // TaprootCommitmentRevoke is a witness that allows us to sweep the
        // settled output of a malicious counterparty's who broadcasts a
        // revoked taproot commitment transaction.
        TaprootCommitmentRevoke StandardWitnessType = 34
)

// String returns a human readable version of the target WitnessType.
//
// NOTE: This is part of the WitnessType interface.
func (wt StandardWitnessType) String() string {
        switch wt {
        case CommitmentTimeLock:
                return "CommitmentTimeLock"

        case CommitmentToRemoteConfirmed:
                return "CommitmentToRemoteConfirmed"

        case CommitmentAnchor:
                return "CommitmentAnchor"

        case CommitmentNoDelay:
                return "CommitmentNoDelay"

        case CommitSpendNoDelayTweakless:
                return "CommitmentNoDelayTweakless"

        case CommitmentRevoke:
                return "CommitmentRevoke"

        case HtlcOfferedRevoke:
                return "HtlcOfferedRevoke"

        case HtlcAcceptedRevoke:
                return "HtlcAcceptedRevoke"

        case HtlcOfferedTimeoutSecondLevel:
                return "HtlcOfferedTimeoutSecondLevel"

        case HtlcOfferedTimeoutSecondLevelInputConfirmed:
                return "HtlcOfferedTimeoutSecondLevelInputConfirmed"

        case HtlcAcceptedSuccessSecondLevel:
                return "HtlcAcceptedSuccessSecondLevel"

        case HtlcAcceptedSuccessSecondLevelInputConfirmed:
                return "HtlcAcceptedSuccessSecondLevelInputConfirmed"

        case HtlcOfferedRemoteTimeout:
                return "HtlcOfferedRemoteTimeout"

        case HtlcAcceptedRemoteSuccess:
                return "HtlcAcceptedRemoteSuccess"

        case HtlcSecondLevelRevoke:
                return "HtlcSecondLevelRevoke"

        case WitnessKeyHash:
                return "WitnessKeyHash"

        case NestedWitnessKeyHash:
                return "NestedWitnessKeyHash"

        case LeaseCommitmentTimeLock:
                return "LeaseCommitmentTimeLock"

        case LeaseCommitmentToRemoteConfirmed:
                return "LeaseCommitmentToRemoteConfirmed"

        case LeaseHtlcOfferedTimeoutSecondLevel:
                return "LeaseHtlcOfferedTimeoutSecondLevel"

        case LeaseHtlcAcceptedSuccessSecondLevel:
                return "LeaseHtlcAcceptedSuccessSecondLevel"

        case TaprootPubKeySpend:
                return "TaprootPubKeySpend"

        case TaprootLocalCommitSpend:
                return "TaprootLocalCommitSpend"

        case TaprootRemoteCommitSpend:
                return "TaprootRemoteCommitSpend"

        case TaprootAnchorSweepSpend:
                return "TaprootAnchorSweepSpend"

        case TaprootHtlcOfferedTimeoutSecondLevel:
                return "TaprootHtlcOfferedTimeoutSecondLevel"

        case TaprootHtlcAcceptedSuccessSecondLevel:
                return "TaprootHtlcAcceptedSuccessSecondLevel"

        case TaprootHtlcSecondLevelRevoke:
                return "TaprootHtlcSecondLevelRevoke"

        case TaprootHtlcAcceptedRevoke:
                return "TaprootHtlcAcceptedRevoke"

        case TaprootHtlcOfferedRevoke:
                return "TaprootHtlcOfferedRevoke"

        case TaprootHtlcOfferedRemoteTimeout:
                return "TaprootHtlcOfferedRemoteTimeout"

        case TaprootHtlcLocalOfferedTimeout:
                return "TaprootHtlcLocalOfferedTimeout"

        case TaprootHtlcAcceptedRemoteSuccess:
                return "TaprootHtlcAcceptedRemoteSuccess"

        case TaprootHtlcAcceptedLocalSuccess:
                return "TaprootHtlcAcceptedLocalSuccess"

        case TaprootCommitmentRevoke:
                return "TaprootCommitmentRevoke"

        default:
                return fmt.Sprintf("Unknown WitnessType: %v", uint32(wt))
        }
}

// WitnessGenerator will return a WitnessGenerator function that an output uses
// to generate the witness and optionally the sigScript for a sweep
// transaction. The sigScript will be generated if the witness type warrants
// one for spending, such as the NestedWitnessKeyHash witness type.
//
// NOTE: This is part of the WitnessType interface.
func (wt StandardWitnessType) WitnessGenerator(signer Signer,
        descriptor *SignDescriptor) WitnessGenerator {

        return func(tx *wire.MsgTx, hc *txscript.TxSigHashes,
                inputIndex int) (*Script, error) {

                // TODO(roasbeef): copy the desc?
                desc := descriptor
                desc.SigHashes = hc
                desc.InputIndex = inputIndex

                switch wt {
                case CommitmentTimeLock, LeaseCommitmentTimeLock:
                        witness, err := CommitSpendTimeout(signer, desc, tx)
                        if err != nil {
                                return nil, err
                        }

                        return &Script{
                                Witness: witness,
                        }, nil

                case CommitmentToRemoteConfirmed, LeaseCommitmentToRemoteConfirmed:
                        witness, err := CommitSpendToRemoteConfirmed(
                                signer, desc, tx,
                        )
                        if err != nil {
                                return nil, err
                        }

                        return &Script{
                                Witness: witness,
                        }, nil

                case CommitmentAnchor:
                        witness, err := CommitSpendAnchor(signer, desc, tx)
                        if err != nil {
                                return nil, err
                        }

                        return &Script{
                                Witness: witness,
                        }, nil

                case CommitmentNoDelay:
                        witness, err := CommitSpendNoDelay(signer, desc, tx, false)
                        if err != nil {
                                return nil, err
                        }

                        return &Script{
                                Witness: witness,
                        }, nil

                case CommitSpendNoDelayTweakless:
                        witness, err := CommitSpendNoDelay(signer, desc, tx, true)
                        if err != nil {
                                return nil, err
                        }

                        return &Script{
                                Witness: witness,
                        }, nil

                case CommitmentRevoke:
                        witness, err := CommitSpendRevoke(signer, desc, tx)
                        if err != nil {
                                return nil, err
                        }

                        return &Script{
                                Witness: witness,
                        }, nil

                case HtlcOfferedRevoke:
                        witness, err := ReceiverHtlcSpendRevoke(signer, desc, tx)
                        if err != nil {
                                return nil, err
                        }

                        return &Script{
                                Witness: witness,
                        }, nil

                case HtlcAcceptedRevoke:
                        witness, err := SenderHtlcSpendRevoke(signer, desc, tx)
                        if err != nil {
                                return nil, err
                        }

                        return &Script{
                                Witness: witness,
                        }, nil

                case HtlcOfferedTimeoutSecondLevel,
                        LeaseHtlcOfferedTimeoutSecondLevel,
                        HtlcAcceptedSuccessSecondLevel,
                        LeaseHtlcAcceptedSuccessSecondLevel:

                        witness, err := HtlcSecondLevelSpend(signer, desc, tx)
                        if err != nil {
                                return nil, err
                        }

                        return &Script{
                                Witness: witness,
                        }, nil

                case HtlcOfferedRemoteTimeout:
                        // We pass in a value of -1 for the timeout, as we
                        // expect the caller to have already set the lock time
                        // value.
                        witness, err := ReceiverHtlcSpendTimeout(signer, desc, tx, -1)
                        if err != nil {
                                return nil, err
                        }

                        return &Script{
                                Witness: witness,
                        }, nil

                case HtlcSecondLevelRevoke:
                        witness, err := HtlcSpendRevoke(signer, desc, tx)
                        if err != nil {
                                return nil, err
                        }

                        return &Script{
                                Witness: witness,
                        }, nil

                case WitnessKeyHash:
                        fallthrough
                case TaprootPubKeySpend:
                        fallthrough
                case NestedWitnessKeyHash:
                        return signer.ComputeInputScript(tx, desc)

                case TaprootLocalCommitSpend:
                        // Ensure that the sign desc has the proper sign method
                        // set, and a valid prev output fetcher.
                        desc.SignMethod = TaprootScriptSpendSignMethod

                        // The control block bytes must be set at this point.
                        if desc.ControlBlock == nil {
                                return nil, fmt.Errorf("control block must " +
                                        "be set for taproot spend")
                        }

                        witness, err := TaprootCommitSpendSuccess(
                                signer, desc, tx, nil,
                        )
                        if err != nil {
                                return nil, err
                        }

                        return &Script{
                                Witness: witness,
                        }, nil

                case TaprootRemoteCommitSpend:
                        // Ensure that the sign desc has the proper sign method
                        // set, and a valid prev output fetcher.
                        desc.SignMethod = TaprootScriptSpendSignMethod

                        // The control block bytes must be set at this point.
                        if desc.ControlBlock == nil {
                                return nil, fmt.Errorf("control block must " +
                                        "be set for taproot spend")
                        }

                        witness, err := TaprootCommitRemoteSpend(
                                signer, desc, tx, nil,
                        )
                        if err != nil {
                                return nil, err
                        }

                        return &Script{
                                Witness: witness,
                        }, nil

                case TaprootAnchorSweepSpend:
                        // Ensure that the sign desc has the proper sign method
                        // set, and a valid prev output fetcher.
                        desc.SignMethod = TaprootKeySpendSignMethod

                        // The tap tweak must be set at this point.
                        if desc.TapTweak == nil {
                                return nil, fmt.Errorf("tap tweak must be " +
                                        "set for keyspend")
                        }

                        witness, err := TaprootAnchorSpend(
                                signer, desc, tx,
                        )
                        if err != nil {
                                return nil, err
                        }

                        return &Script{
                                Witness: witness,
                        }, nil

                case TaprootHtlcOfferedTimeoutSecondLevel,
                        TaprootHtlcAcceptedSuccessSecondLevel:
                        // Ensure that the sign desc has the proper sign method
                        // set, and a valid prev output fetcher.
                        desc.SignMethod = TaprootScriptSpendSignMethod

                        // The control block bytes must be set at this point.
                        if desc.ControlBlock == nil {
                                return nil, fmt.Errorf("control block must " +
                                        "be set for taproot spend")
                        }

                        witness, err := TaprootHtlcSpendSuccess(
                                signer, desc, tx, nil, nil,
                        )
                        if err != nil {
                                return nil, err
                        }

                        return &Script{
                                Witness: witness,
                        }, nil

                case TaprootHtlcSecondLevelRevoke:
                        // Ensure that the sign desc has the proper sign method
                        // set, and a valid prev output fetcher.
                        desc.SignMethod = TaprootKeySpendSignMethod

                        // The tap tweak must be set at this point.
                        if desc.TapTweak == nil {
                                return nil, fmt.Errorf("tap tweak must be " +
                                        "set for keyspend")
                        }

                        witness, err := TaprootHtlcSpendRevoke(
                                signer, desc, tx,
                        )
                        if err != nil {
                                return nil, err
                        }

                        return &Script{
                                Witness: witness,
                        }, nil

                case TaprootHtlcOfferedRevoke:
                        // Ensure that the sign desc has the proper sign method
                        // set, and a valid prev output fetcher.
                        desc.SignMethod = TaprootKeySpendSignMethod

                        // The tap tweak must be set at this point.
                        if desc.TapTweak == nil {
                                return nil, fmt.Errorf("tap tweak must be " +
                                        "set for keyspend")
                        }

                        witness, err := SenderHTLCScriptTaprootRevoke(
                                signer, desc, tx,
                        )
                        if err != nil {
                                return nil, err
                        }

                        return &Script{
                                Witness: witness,
                        }, nil

                case TaprootHtlcAcceptedRevoke:
                        // Ensure that the sign desc has the proper sign method
                        // set, and a valid prev output fetcher.
                        desc.SignMethod = TaprootKeySpendSignMethod

                        // The tap tweak must be set at this point.
                        if desc.TapTweak == nil {
                                return nil, fmt.Errorf("tap tweak must be " +
                                        "set for keyspend")
                        }

                        witness, err := ReceiverHTLCScriptTaprootRevoke(
                                signer, desc, tx,
                        )
                        if err != nil {
                                return nil, err
                        }

                        return &Script{
                                Witness: witness,
                        }, nil

                case TaprootHtlcOfferedRemoteTimeout:
                        // Ensure that the sign desc has the proper sign method
                        // set, and a valid prev output fetcher.
                        desc.SignMethod = TaprootScriptSpendSignMethod

                        // The control block bytes must be set at this point.
                        if desc.ControlBlock == nil {
                                return nil, fmt.Errorf("control block " +
                                        "must be set for taproot spend")
                        }

                        witness, err := ReceiverHTLCScriptTaprootTimeout(
                                signer, desc, tx, -1, nil, nil,
                        )
                        if err != nil {
                                return nil, err
                        }

                        return &Script{
                                Witness: witness,
                        }, nil

                case TaprootCommitmentRevoke:
                        // Ensure that the sign desc has the proper sign method
                        // set, and a valid prev output fetcher.
                        desc.SignMethod = TaprootScriptSpendSignMethod

                        // The control block bytes must be set at this point.
                        if desc.ControlBlock == nil {
                                return nil, fmt.Errorf("control block " +
                                        "must be set for taproot spend")
                        }

                        witness, err := TaprootCommitSpendRevoke(
                                signer, desc, tx, nil,
                        )
                        if err != nil {
                                return nil, err
                        }

                        return &Script{
                                Witness: witness,
                        }, nil

                default:
                        return nil, fmt.Errorf("unknown witness type: %v", wt)
                }
        }
}

// SizeUpperBound returns the maximum length of the witness of this witness
// type if it would be included in a tx. We also return if the output itself is
// a nested p2sh output, if so then we need to take into account the extra
// sigScript data size.
//
// NOTE: This is part of the WitnessType interface.
func (wt StandardWitnessType) SizeUpperBound() (lntypes.WeightUnit,
        bool, error) {

        switch wt {
        // Outputs on a remote commitment transaction that pay directly to us.
        case CommitSpendNoDelayTweakless:
                fallthrough
        case WitnessKeyHash:
                fallthrough
        case CommitmentNoDelay:
                return P2WKHWitnessSize, false, nil

        // Outputs on a past commitment transaction that pay directly
        // to us.
        case CommitmentTimeLock:
                return ToLocalTimeoutWitnessSize, false, nil
        case LeaseCommitmentTimeLock:
                size := ToLocalTimeoutWitnessSize +
                        LeaseWitnessScriptSizeOverhead

                return lntypes.WeightUnit(size), false, nil

        // 1 CSV time locked output to us on remote commitment.
        case CommitmentToRemoteConfirmed:
                return ToRemoteConfirmedWitnessSize, false, nil
        case LeaseCommitmentToRemoteConfirmed:
                size := ToRemoteConfirmedWitnessSize +
                        LeaseWitnessScriptSizeOverhead

                return lntypes.WeightUnit(size), false, nil

        // Anchor output on the commitment transaction.
        case CommitmentAnchor:
                return AnchorWitnessSize, false, nil

        // Outgoing second layer HTLC's that have confirmed within the
        // chain, and the output they produced is now mature enough to
        // sweep.
        case HtlcOfferedTimeoutSecondLevel:
                return ToLocalTimeoutWitnessSize, false, nil
        case LeaseHtlcOfferedTimeoutSecondLevel:
                size := ToLocalTimeoutWitnessSize +
                        LeaseWitnessScriptSizeOverhead

                return lntypes.WeightUnit(size), false, nil

        // Input to the outgoing HTLC second layer timeout transaction.
        case HtlcOfferedTimeoutSecondLevelInputConfirmed:
                return OfferedHtlcTimeoutWitnessSizeConfirmed, false, nil

        // Incoming second layer HTLC's that have confirmed within the
        // chain, and the output they produced is now mature enough to
        // sweep.
        case HtlcAcceptedSuccessSecondLevel:
                return ToLocalTimeoutWitnessSize, false, nil
        case LeaseHtlcAcceptedSuccessSecondLevel:
                size := ToLocalTimeoutWitnessSize +
                        LeaseWitnessScriptSizeOverhead

                return lntypes.WeightUnit(size), false, nil

        // Input to the incoming second-layer HTLC success transaction.
        case HtlcAcceptedSuccessSecondLevelInputConfirmed:
                return AcceptedHtlcSuccessWitnessSizeConfirmed, false, nil

        // An HTLC on the commitment transaction of the remote party,
        // that has had its absolute timelock expire.
        case HtlcOfferedRemoteTimeout:
                return AcceptedHtlcTimeoutWitnessSize, false, nil

        // An HTLC on the commitment transaction of the remote party,
        // that can be swept with the preimage.
        case HtlcAcceptedRemoteSuccess:
                return OfferedHtlcSuccessWitnessSize, false, nil

        // A nested P2SH input that has a p2wkh witness script. We'll mark this
        // as nested P2SH so the caller can estimate the weight properly
        // including the sigScript.
        case NestedWitnessKeyHash:
                return P2WKHWitnessSize, true, nil

        // The revocation output on a revoked commitment transaction.
        case CommitmentRevoke:
                return ToLocalPenaltyWitnessSize, false, nil

        // The revocation output on a revoked HTLC that we offered to the remote
        // party.
        case HtlcOfferedRevoke:
                return OfferedHtlcPenaltyWitnessSize, false, nil

        // The revocation output on a revoked HTLC that was sent to us.
        case HtlcAcceptedRevoke:
                return AcceptedHtlcPenaltyWitnessSize, false, nil

        // The revocation output of a second level output of an HTLC.
        case HtlcSecondLevelRevoke:
                return ToLocalPenaltyWitnessSize, false, nil

        case TaprootPubKeySpend:
                return TaprootKeyPathCustomSighashWitnessSize, false, nil

        // Sweeping a self output after a delay for taproot channels.
        case TaprootLocalCommitSpend:
                return TaprootToLocalWitnessSize, false, nil

        // Sweeping a self output after the remote party fro ce closes. Must
        // wait 1 CSV.
        case TaprootRemoteCommitSpend:
                return TaprootToRemoteWitnessSize, false, nil

        // Sweeping our anchor output with a key spend witness.
        case TaprootAnchorSweepSpend:
                return TaprootAnchorWitnessSize, false, nil

        case TaprootHtlcOfferedTimeoutSecondLevel,
                TaprootHtlcAcceptedSuccessSecondLevel:

                return TaprootSecondLevelHtlcWitnessSize, false, nil

        case TaprootHtlcSecondLevelRevoke:
                return TaprootSecondLevelRevokeWitnessSize, false, nil

        case TaprootHtlcAcceptedRevoke:
                return TaprootAcceptedRevokeWitnessSize, false, nil

        case TaprootHtlcOfferedRevoke:
                return TaprootOfferedRevokeWitnessSize, false, nil

        case TaprootHtlcOfferedRemoteTimeout:
                return TaprootHtlcOfferedRemoteTimeoutWitnessSize, false, nil

        case TaprootHtlcLocalOfferedTimeout:
                return TaprootOfferedLocalTimeoutWitnessSize, false, nil

        case TaprootHtlcAcceptedRemoteSuccess:
                return TaprootHtlcAcceptedRemoteSuccessWitnessSize, false, nil

        case TaprootHtlcAcceptedLocalSuccess:
                return TaprootHtlcAcceptedLocalSuccessWitnessSize, false, nil

        case TaprootCommitmentRevoke:
                return TaprootToLocalRevokeWitnessSize, false, nil
        }

        return 0, false, fmt.Errorf("unexpected witness type: %v", wt)
}

// AddWeightEstimation adds the estimated size of the witness in bytes to the
// given weight estimator.
//
// NOTE: This is part of the WitnessType interface.
func (wt StandardWitnessType) AddWeightEstimation(e *TxWeightEstimator) error {
        // For fee estimation purposes, we'll now attempt to obtain an
        // upper bound on the weight this input will add when fully
        // populated.
        size, isNestedP2SH, err := wt.SizeUpperBound()
        if err != nil {
                return err
        }

        // If this is a nested P2SH input, then we'll need to factor in
        // the additional data push within the sigScript.
        if isNestedP2SH {
                e.AddNestedP2WSHInput(size)
        } else {
                e.AddWitnessInput(size)
        }

        return nil
}

lightningnetwork / lnd / 12199391122

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