/
merge.go
170 lines (139 loc) · 4.12 KB
/
merge.go
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package chanacceptor
import (
"bytes"
"fmt"
"github.com/btcsuite/btcd/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"
)
var (
errZeroConf = fmt.Errorf("zero-conf set with non-zero min-depth")
)
// 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, newValue interface{}) error {
return fmt.Errorf("multiple values set for: %v, %v and %v",
name, current, newValue)
}
// mergeBool merges two boolean values.
func mergeBool(current, newValue bool) bool {
// If either is true, return true. It is not possible to have different
// "non-zero" values like the other cases.
return current || newValue
}
// mergeInt64 merges two int64 values, failing if they have different non-zero
// values.
func mergeInt64(name string, current, newValue int64) (int64, error) {
switch {
case current == 0:
return newValue, nil
case newValue == 0:
return current, nil
case current != newValue:
return 0, fieldMismatchError(name, current, newValue)
default:
return newValue, nil
}
}
// mergeMillisatoshi merges two msat values, failing if they have different
// non-zero values.
func mergeMillisatoshi(name string, current,
newValue lnwire.MilliSatoshi) (lnwire.MilliSatoshi, error) {
switch {
case current == 0:
return newValue, nil
case newValue == 0:
return current, nil
case current != newValue:
return 0, fieldMismatchError(name, current, newValue)
default:
return newValue, nil
}
}
// mergeDeliveryAddress merges two delivery address values, failing if they have
// different non-zero values.
func mergeDeliveryAddress(name string, current,
newValue lnwire.DeliveryAddress) (lnwire.DeliveryAddress, error) {
switch {
case current == nil:
return newValue, nil
case newValue == nil:
return current, nil
case !bytes.Equal(current, newValue):
return nil, fieldMismatchError(name, current, newValue)
default:
return newValue, 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,
newValue ChannelAcceptResponse) (ChannelAcceptResponse, error) {
csv, err := mergeInt64(
fieldCSV, int64(current.CSVDelay), int64(newValue.CSVDelay),
)
if err != nil {
return current, err
}
current.CSVDelay = uint16(csv)
htlcLimit, err := mergeInt64(
fieldHtlcLimit, int64(current.HtlcLimit),
int64(newValue.HtlcLimit),
)
if err != nil {
return current, err
}
current.HtlcLimit = uint16(htlcLimit)
minDepth, err := mergeInt64(
fieldMinDep, int64(current.MinAcceptDepth),
int64(newValue.MinAcceptDepth),
)
if err != nil {
return current, err
}
current.MinAcceptDepth = uint16(minDepth)
current.ZeroConf = mergeBool(current.ZeroConf, newValue.ZeroConf)
// Assert that if zero-conf is set, min-depth is zero.
if current.ZeroConf && current.MinAcceptDepth != 0 {
return current, errZeroConf
}
reserve, err := mergeInt64(
fieldReserve, int64(current.Reserve), int64(newValue.Reserve),
)
if err != nil {
return current, err
}
current.Reserve = btcutil.Amount(reserve)
current.MinHtlcIn, err = mergeMillisatoshi(
fieldMinIn, current.MinHtlcIn, newValue.MinHtlcIn,
)
if err != nil {
return current, err
}
current.InFlightTotal, err = mergeMillisatoshi(
fieldInFlightTotal, current.InFlightTotal,
newValue.InFlightTotal,
)
if err != nil {
return current, err
}
current.UpfrontShutdown, err = mergeDeliveryAddress(
fieldUpfrontShutdown, current.UpfrontShutdown,
newValue.UpfrontShutdown,
)
if err != nil {
return current, err
}
return current, nil
}