lnd.xprv/chanacceptor/merge.go

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package chanacceptor
import (
"bytes"
"fmt"
"github.com/btcsuite/btcutil"
"github.com/lightningnetwork/lnd/lnwire"
)
const (
// We use field names in our errors for more readable errors. Create
// consts for them here so that we can exactly match in our unit tests.
fieldCSV = "csv delay"
fieldHtlcLimit = "htlc limit"
fieldMinDep = "min depth"
fieldReserve = "reserve"
fieldMinIn = "min htlc in"
fieldInFlightTotal = "in flight total"
fieldUpfrontShutdown = "upfront shutdown"
)
// fieldMismatchError returns a merge error for a named field when we get two
// channel acceptor responses which have different values set.
func fieldMismatchError(name string, current, new interface{}) error {
return fmt.Errorf("multiple values set for: %v, %v and %v",
name, current, new)
}
// mergeInt64 merges two int64 values, failing if they have different non-zero
// values.
func mergeInt64(name string, current, new int64) (int64, error) {
switch {
case current == 0:
return new, nil
case new == 0:
return current, nil
case current != new:
return 0, fieldMismatchError(name, current, new)
default:
return new, nil
}
}
// mergeMillisatoshi merges two msat values, failing if they have different
// non-zero values.
func mergeMillisatoshi(name string, current,
new lnwire.MilliSatoshi) (lnwire.MilliSatoshi, error) {
switch {
case current == 0:
return new, nil
case new == 0:
return current, nil
case current != new:
return 0, fieldMismatchError(name, current, new)
default:
return new, nil
}
}
// mergeDeliveryAddress merges two delivery address values, failing if they have
// different non-zero values.
func mergeDeliveryAddress(name string, current,
new lnwire.DeliveryAddress) (lnwire.DeliveryAddress, error) {
switch {
case current == nil:
return new, nil
case new == nil:
return current, nil
case !bytes.Equal(current, new):
return nil, fieldMismatchError(name, current, new)
default:
return new, nil
}
}
// mergeResponse takes two channel accept responses, and attempts to merge their
// fields, failing if any fields conflict (are non-zero and not equal). It
// returns a new response that has all the merged fields in it.
func mergeResponse(current, new ChannelAcceptResponse) (ChannelAcceptResponse,
error) {
csv, err := mergeInt64(
fieldCSV, int64(current.CSVDelay), int64(new.CSVDelay),
)
if err != nil {
return current, err
}
current.CSVDelay = uint16(csv)
htlcLimit, err := mergeInt64(
fieldHtlcLimit, int64(current.HtlcLimit),
int64(new.HtlcLimit),
)
if err != nil {
return current, err
}
current.HtlcLimit = uint16(htlcLimit)
minDepth, err := mergeInt64(
fieldMinDep, int64(current.MinAcceptDepth),
int64(new.MinAcceptDepth),
)
if err != nil {
return current, err
}
current.MinAcceptDepth = uint16(minDepth)
reserve, err := mergeInt64(
fieldReserve, int64(current.Reserve), int64(new.Reserve),
)
if err != nil {
return current, err
}
current.Reserve = btcutil.Amount(reserve)
current.MinHtlcIn, err = mergeMillisatoshi(
fieldMinIn, current.MinHtlcIn, new.MinHtlcIn,
)
if err != nil {
return current, err
}
current.InFlightTotal, err = mergeMillisatoshi(
fieldInFlightTotal, current.InFlightTotal,
new.InFlightTotal,
)
if err != nil {
return current, err
}
current.UpfrontShutdown, err = mergeDeliveryAddress(
fieldUpfrontShutdown, current.UpfrontShutdown,
new.UpfrontShutdown,
)
if err != nil {
return current, err
}
return current, nil
}