Factor out a function to turn a KeyValue error into a string

I can use this in several places to include stderr in the error dialog,
when available.

ui/prochandlers.go

@@ -8,8 +8,6 @@ package ui
 import (
 	"fmt"
 	"os"
-	"sort"
-	"strings"
 	"time"
 
 	"github.com/gcla/gowid"
@@ -125,17 +123,7 @@ func (t updatePacketViews) OnError(code pcap.HandlerCode, app gowid.IApp, err er
 		if !profiles.ConfBool("main.suppress-tshark-errors", true) {
 			var errstr string
 			if kverr, ok := err.(gowid.KeyValueError); ok {
-				errstr = fmt.Sprintf("%v\n\n", kverr.Cause())
-				kvs := make([]string, 0, len(kverr.KeyVals))
-				ks := make([]string, 0, len(kverr.KeyVals))
-				for k := range kverr.KeyVals {
-					ks = append(ks, k)
-				}
-				sort.Sort(sort.StringSlice(ks))
-				for _, k := range ks {
-					kvs = append(kvs, fmt.Sprintf("%v: %v", k, kverr.KeyVals[k]))
-				}
-				errstr = errstr + strings.Join(kvs, "\n\n")
+				errstr = termshark.KeyValueErrorString(kverr)
 			} else {
 				errstr = fmt.Sprintf("%v", err)
 			}

ui/streamui.go

@@ -8,7 +8,6 @@ package ui
 import (
 	"fmt"
 	"os"
-	"strings"
 	"sync"
 	"time"
 
@@ -343,18 +342,13 @@ func (t *streamParseHandler) OnError(code pcap.HandlerCode, app gowid.IApp, err
 	} else if !profiles.ConfBool("main.suppress-tshark-errors", true) {
 		var errstr string
 		if kverr, ok := err.(gowid.KeyValueError); ok {
-			errstr = fmt.Sprintf("%v\n\n", kverr.Cause())
-			kvs := make([]string, 0, len(kverr.KeyVals))
-			for k, v := range kverr.KeyVals {
-				kvs = append(kvs, fmt.Sprintf("%v: %v", k, v))
-			}
-			errstr = errstr + strings.Join(kvs, "\n")
+			errstr = termshark.KeyValueErrorString(kverr)
 		} else {
 			errstr = fmt.Sprintf("%v", err)
 		}
 
 		app.Run(gowid.RunFunction(func(app gowid.IApp) {
-			OpenError(errstr, app)
+			OpenLongError(errstr, app)
 		}))
 	}
 }

utils.go

@@ -683,6 +683,24 @@ func ErrLogger(key string, val string) *io.PipeWriter {
 	return log.NewEntry(l).WithField(key, val).WriterLevel(log.ErrorLevel)
 }
 
+// KeyValueErrorString returns a string representation of
+// a gowid KeyValueError intended to be suitable for displaying in
+// a termshark error dialog.
+func KeyValueErrorString(err gowid.KeyValueError) string {
+	res := fmt.Sprintf("%v\n\n", err.Cause())
+	kvs := make([]string, 0, len(err.KeyVals))
+	ks := make([]string, 0, len(err.KeyVals))
+	for k := range err.KeyVals {
+		ks = append(ks, k)
+	}
+	sort.Sort(sort.StringSlice(ks))
+	for _, k := range ks {
+		kvs = append(kvs, fmt.Sprintf("%v: %v", k, err.KeyVals[k]))
+	}
+	res = res + strings.Join(kvs, "\n\n")
+	return res
+}
+
 //======================================================================
 
 // Need to publish fields for template use