termdash/private/faketerm/diff.go

112 lines
3.1 KiB
Go

// Copyright 2018 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package faketerm
// diff.go provides functions that highlight differences between fake terminals.
import (
"fmt"
"image"
"reflect"
"strings"
"github.com/kylelemons/godebug/pretty"
"github.com/mum4k/termdash/cell"
)
// optDiff is used to display differences in cell options.
type optDiff struct {
// point indicates the cell with the differing options.
point image.Point
got *cell.Options
want *cell.Options
}
// Diff compares the two terminals, returning an empty string if there is not
// difference. If a difference is found, returns a human readable description
// of the differences.
func Diff(want, got *Terminal) string {
if reflect.DeepEqual(want.BackBuffer(), got.BackBuffer()) {
return ""
}
var b strings.Builder
b.WriteString("found differences between the two fake terminals.\n")
b.WriteString(" got:\n")
b.WriteString(got.String())
b.WriteString(" want:\n")
b.WriteString(want.String())
b.WriteString(" diff (unexpected cells highlighted with rune '࿃')\n")
b.WriteString(" note - this excludes cell options:\n")
size := got.Size()
var optDiffs []*optDiff
cellsDiffer := false
for row := 0; row < size.Y; row++ {
for col := 0; col < size.X; col++ {
p := image.Point{col, row}
partial, err := got.BackBuffer().IsPartial(p)
if err != nil {
panic(fmt.Errorf("unable to determine if point %v is a partial rune: %v", p, err))
}
gotCell := got.BackBuffer()[col][row]
wantCell := want.BackBuffer()[col][row]
r := gotCell.Rune
if r != wantCell.Rune {
r = '࿃'
cellsDiffer = true
} else if r == 0 && !partial {
r = ' '
}
b.WriteRune(r)
if !reflect.DeepEqual(gotCell.Opts, wantCell.Opts) {
optDiffs = append(optDiffs, &optDiff{
point: image.Point{col, row},
got: gotCell.Opts,
want: wantCell.Opts,
})
}
}
b.WriteRune('\n')
}
if len(optDiffs) > 0 {
b.WriteString(" Found differences in options on some of the cells:\n")
for _, od := range optDiffs {
if diff := pretty.Compare(od.want, od.got); diff != "" {
b.WriteString(fmt.Sprintf("cell %v, diff (-want +got):\n%s\n", od.point, diff))
}
}
}
if cellsDiffer {
b.WriteString(" Found differences in some of the cell runes:\n")
for row := 0; row < size.Y; row++ {
for col := 0; col < size.X; col++ {
got := got.BackBuffer()[col][row].Rune
want := want.BackBuffer()[col][row].Rune
if got == want {
continue
}
b.WriteString(fmt.Sprintf(" cell(%v, %v) => got '%c' (rune %d), want '%c' (rune %d)\n", col, row, got, got, want, want))
}
}
}
return b.String()
}