multi: add NewLogClosure in lnutils to avoid repetition

And replaces all usage of `logClosure` with `lnutils.LogClosure`.

routing/log.go

@@ -31,19 +31,3 @@ func UseLogger(logger btclog.Logger) {
 	log = logger
 	chainview.UseLogger(logger)
 }
-
-// logClosure is used to provide a closure over expensive logging operations so
-// don't have to be performed when the logging level doesn't warrant it.
-type logClosure func() string
-
-// String invokes the underlying function and returns the result.
-func (c logClosure) String() string {
-	return c()
-}
-
-// newLogClosure returns a new closure over a function that returns a string
-// which itself provides a Stringer interface so that it can be used with the
-// logging system.
-func newLogClosure(c func() string) logClosure {
-	return logClosure(c)
-}

routing/pathfind.go

@@ -13,6 +13,7 @@ import (
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/channeldb/models"
 	"github.com/lightningnetwork/lnd/feature"
+	"github.com/lightningnetwork/lnd/lnutils"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/record"
 	"github.com/lightningnetwork/lnd/routing/route"
@@ -728,7 +729,7 @@ func findPath(g *graphParams, r *RestrictParams, cfg *PathFindingConfig,
 			edge.capacity,
 		)
 
-		log.Trace(newLogClosure(func() string {
+		log.Trace(lnutils.NewLogClosure(func() string {
 			return fmt.Sprintf("path finding probability: fromnode=%v,"+
 				" tonode=%v, amt=%v, cap=%v, probability=%v",
 				fromVertex, toNodeDist.node, amountToSend,

routing/payment_session.go

@@ -10,6 +10,7 @@ import (
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/channeldb/models"
 	"github.com/lightningnetwork/lnd/graph"
+	"github.com/lightningnetwork/lnd/lnutils"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/routing/route"
 )
@@ -432,7 +433,7 @@ func (p *paymentSession) UpdateAdditionalEdge(msg *lnwire.ChannelUpdate,
 	policy.FeeProportionalMillionths = lnwire.MilliSatoshi(msg.FeeRate)
 
 	log.Debugf("New private channel update applied: %v",
-		newLogClosure(func() string { return spew.Sdump(msg) }))
+		lnutils.NewLogClosure(func() string { return spew.Sdump(msg) }))
 
 	return true
 }

routing/router.go

@@ -21,6 +21,7 @@ import (
 	"github.com/lightningnetwork/lnd/fn"
 	"github.com/lightningnetwork/lnd/htlcswitch"
 	"github.com/lightningnetwork/lnd/lntypes"
+	"github.com/lightningnetwork/lnd/lnutils"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/record"
@@ -669,7 +670,7 @@ func (r *ChannelRouter) FindRoute(req *RouteRequest) (*route.Route, float64,
 	}
 
 	go log.Tracef("Obtained path to send %v to %x: %v",
-		req.Amount, req.Target, newLogClosure(func() string {
+		req.Amount, req.Target, lnutils.NewLogClosure(func() string {
 			return spew.Sdump(route)
 		}),
 	)
@@ -704,7 +705,7 @@ func generateSphinxPacket(rt *route.Route, paymentHash []byte,
 	}
 
 	log.Tracef("Constructed per-hop payloads for payment_hash=%x: %v",
-		paymentHash[:], newLogClosure(func() string {
+		paymentHash, lnutils.NewLogClosure(func() string {
 			path := make(
 				[]sphinx.OnionHop, sphinxPath.TrueRouteLength(),
 			)
@@ -734,7 +735,7 @@ func generateSphinxPacket(rt *route.Route, paymentHash []byte,
 	}
 
 	log.Tracef("Generated sphinx packet: %v",
-		newLogClosure(func() string {
+		lnutils.NewLogClosure(func() string {
 			// We make a copy of the ephemeral key and unset the
 			// internal curve here in order to keep the logs from
 			// getting noisy.
@@ -945,8 +946,8 @@ func (r *ChannelRouter) SendPaymentAsync(ctx context.Context,
 
 // spewPayment returns a log closures that provides a spewed string
 // representation of the passed payment.
-func spewPayment(payment *LightningPayment) logClosure {
-	return newLogClosure(func() string {
+func spewPayment(payment *LightningPayment) lnutils.LogClosure {
+	return lnutils.NewLogClosure(func() string {
 		// Make a copy of the payment with a nilled Curve
 		// before spewing.
 		var routeHints [][]zpay32.HopHint
@@ -1091,7 +1092,7 @@ func (r *ChannelRouter) sendToRoute(htlcHash lntypes.Hash, rt *route.Route,
 	}
 
 	log.Tracef("Dispatching SendToRoute for HTLC hash %v: %v",
-		htlcHash, newLogClosure(func() string {
+		htlcHash, lnutils.NewLogClosure(func() string {
 			return spew.Sdump(rt)
 		}),
 	)