route/vendor/github.com/kr/pretty/diff.go

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2017-01-23 16:04:33 +00:00
package pretty
import (
"fmt"
"io"
"reflect"
)
type sbuf []string
func (s *sbuf) Write(b []byte) (int, error) {
*s = append(*s, string(b))
return len(b), nil
}
// Diff returns a slice where each element describes
// a difference between a and b.
func Diff(a, b interface{}) (desc []string) {
Fdiff((*sbuf)(&desc), a, b)
return desc
}
// Fdiff writes to w a description of the differences between a and b.
func Fdiff(w io.Writer, a, b interface{}) {
diffWriter{w: w}.diff(reflect.ValueOf(a), reflect.ValueOf(b))
}
type diffWriter struct {
w io.Writer
l string // label
}
func (w diffWriter) printf(f string, a ...interface{}) {
var l string
if w.l != "" {
l = w.l + ": "
}
fmt.Fprintf(w.w, l+f, a...)
}
func (w diffWriter) diff(av, bv reflect.Value) {
if !av.IsValid() && bv.IsValid() {
w.printf("nil != %#v", bv.Interface())
return
}
if av.IsValid() && !bv.IsValid() {
w.printf("%#v != nil", av.Interface())
return
}
if !av.IsValid() && !bv.IsValid() {
return
}
at := av.Type()
bt := bv.Type()
if at != bt {
w.printf("%v != %v", at, bt)
return
}
// numeric types, including bool
if at.Kind() < reflect.Array {
a, b := av.Interface(), bv.Interface()
if a != b {
w.printf("%#v != %#v", a, b)
}
return
}
switch at.Kind() {
case reflect.String:
a, b := av.Interface(), bv.Interface()
if a != b {
w.printf("%q != %q", a, b)
}
case reflect.Ptr:
switch {
case av.IsNil() && !bv.IsNil():
w.printf("nil != %v", bv.Interface())
case !av.IsNil() && bv.IsNil():
w.printf("%v != nil", av.Interface())
case !av.IsNil() && !bv.IsNil():
w.diff(av.Elem(), bv.Elem())
}
case reflect.Struct:
for i := 0; i < av.NumField(); i++ {
w.relabel(at.Field(i).Name).diff(av.Field(i), bv.Field(i))
}
case reflect.Slice:
lenA := av.Len()
lenB := bv.Len()
if lenA != lenB {
w.printf("%s[%d] != %s[%d]", av.Type(), lenA, bv.Type(), lenB)
break
}
for i := 0; i < lenA; i++ {
w.relabel(fmt.Sprintf("[%d]", i)).diff(av.Index(i), bv.Index(i))
}
case reflect.Map:
ak, both, bk := keyDiff(av.MapKeys(), bv.MapKeys())
for _, k := range ak {
w := w.relabel(fmt.Sprintf("[%#v]", k.Interface()))
w.printf("%q != (missing)", av.MapIndex(k))
}
for _, k := range both {
w := w.relabel(fmt.Sprintf("[%#v]", k.Interface()))
w.diff(av.MapIndex(k), bv.MapIndex(k))
}
for _, k := range bk {
w := w.relabel(fmt.Sprintf("[%#v]", k.Interface()))
w.printf("(missing) != %q", bv.MapIndex(k))
}
case reflect.Interface:
w.diff(reflect.ValueOf(av.Interface()), reflect.ValueOf(bv.Interface()))
default:
if !reflect.DeepEqual(av.Interface(), bv.Interface()) {
w.printf("%# v != %# v", Formatter(av.Interface()), Formatter(bv.Interface()))
}
}
}
func (d diffWriter) relabel(name string) (d1 diffWriter) {
d1 = d
if d.l != "" && name[0] != '[' {
d1.l += "."
}
d1.l += name
return d1
}
func keyDiff(a, b []reflect.Value) (ak, both, bk []reflect.Value) {
for _, av := range a {
inBoth := false
for _, bv := range b {
if reflect.DeepEqual(av.Interface(), bv.Interface()) {
inBoth = true
both = append(both, av)
break
}
}
if !inBoth {
ak = append(ak, av)
}
}
for _, bv := range b {
inBoth := false
for _, av := range a {
if reflect.DeepEqual(av.Interface(), bv.Interface()) {
inBoth = true
break
}
}
if !inBoth {
bk = append(bk, bv)
}
}
return
}