open-consul/vendor/github.com/google/go-cmp/cmp/report_text.go

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2020-09-25 17:40:44 +00:00
// Copyright 2019, The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE.md file.
package cmp
import (
"bytes"
"fmt"
"math/rand"
"strings"
"time"
"unicode/utf8"
"github.com/google/go-cmp/cmp/internal/flags"
)
var randBool = rand.New(rand.NewSource(time.Now().Unix())).Intn(2) == 0
const maxColumnLength = 80
type indentMode int
func (n indentMode) appendIndent(b []byte, d diffMode) []byte {
// The output of Diff is documented as being unstable to provide future
// flexibility in changing the output for more humanly readable reports.
// This logic intentionally introduces instability to the exact output
// so that users can detect accidental reliance on stability early on,
// rather than much later when an actual change to the format occurs.
if flags.Deterministic || randBool {
// Use regular spaces (U+0020).
switch d {
case diffUnknown, diffIdentical:
b = append(b, " "...)
case diffRemoved:
b = append(b, "- "...)
case diffInserted:
b = append(b, "+ "...)
}
} else {
// Use non-breaking spaces (U+00a0).
switch d {
case diffUnknown, diffIdentical:
b = append(b, "  "...)
case diffRemoved:
b = append(b, "- "...)
case diffInserted:
b = append(b, "+ "...)
}
}
return repeatCount(n).appendChar(b, '\t')
}
type repeatCount int
func (n repeatCount) appendChar(b []byte, c byte) []byte {
for ; n > 0; n-- {
b = append(b, c)
}
return b
}
// textNode is a simplified tree-based representation of structured text.
// Possible node types are textWrap, textList, or textLine.
type textNode interface {
// Len reports the length in bytes of a single-line version of the tree.
// Nested textRecord.Diff and textRecord.Comment fields are ignored.
Len() int
// Equal reports whether the two trees are structurally identical.
// Nested textRecord.Diff and textRecord.Comment fields are compared.
Equal(textNode) bool
// String returns the string representation of the text tree.
// It is not guaranteed that len(x.String()) == x.Len(),
// nor that x.String() == y.String() implies that x.Equal(y).
String() string
// formatCompactTo formats the contents of the tree as a single-line string
// to the provided buffer. Any nested textRecord.Diff and textRecord.Comment
// fields are ignored.
//
// However, not all nodes in the tree should be collapsed as a single-line.
// If a node can be collapsed as a single-line, it is replaced by a textLine
// node. Since the top-level node cannot replace itself, this also returns
// the current node itself.
//
// This does not mutate the receiver.
formatCompactTo([]byte, diffMode) ([]byte, textNode)
// formatExpandedTo formats the contents of the tree as a multi-line string
// to the provided buffer. In order for column alignment to operate well,
// formatCompactTo must be called before calling formatExpandedTo.
formatExpandedTo([]byte, diffMode, indentMode) []byte
}
// textWrap is a wrapper that concatenates a prefix and/or a suffix
// to the underlying node.
type textWrap struct {
Prefix string // e.g., "bytes.Buffer{"
Value textNode // textWrap | textList | textLine
Suffix string // e.g., "}"
Metadata interface{} // arbitrary metadata; has no effect on formatting
}
func (s *textWrap) Len() int {
return len(s.Prefix) + s.Value.Len() + len(s.Suffix)
}
func (s1 *textWrap) Equal(s2 textNode) bool {
if s2, ok := s2.(*textWrap); ok {
return s1.Prefix == s2.Prefix && s1.Value.Equal(s2.Value) && s1.Suffix == s2.Suffix
}
return false
}
func (s *textWrap) String() string {
var d diffMode
var n indentMode
_, s2 := s.formatCompactTo(nil, d)
b := n.appendIndent(nil, d) // Leading indent
b = s2.formatExpandedTo(b, d, n) // Main body
b = append(b, '\n') // Trailing newline
return string(b)
}
func (s *textWrap) formatCompactTo(b []byte, d diffMode) ([]byte, textNode) {
n0 := len(b) // Original buffer length
b = append(b, s.Prefix...)
b, s.Value = s.Value.formatCompactTo(b, d)
b = append(b, s.Suffix...)
if _, ok := s.Value.(textLine); ok {
return b, textLine(b[n0:])
}
return b, s
}
func (s *textWrap) formatExpandedTo(b []byte, d diffMode, n indentMode) []byte {
b = append(b, s.Prefix...)
b = s.Value.formatExpandedTo(b, d, n)
b = append(b, s.Suffix...)
return b
}
// textList is a comma-separated list of textWrap or textLine nodes.
// The list may be formatted as multi-lines or single-line at the discretion
// of the textList.formatCompactTo method.
type textList []textRecord
type textRecord struct {
Diff diffMode // e.g., 0 or '-' or '+'
Key string // e.g., "MyField"
Value textNode // textWrap | textLine
ElideComma bool // avoid trailing comma
Comment fmt.Stringer // e.g., "6 identical fields"
}
// AppendEllipsis appends a new ellipsis node to the list if none already
// exists at the end. If cs is non-zero it coalesces the statistics with the
// previous diffStats.
func (s *textList) AppendEllipsis(ds diffStats) {
hasStats := !ds.IsZero()
if len(*s) == 0 || !(*s)[len(*s)-1].Value.Equal(textEllipsis) {
if hasStats {
*s = append(*s, textRecord{Value: textEllipsis, ElideComma: true, Comment: ds})
} else {
*s = append(*s, textRecord{Value: textEllipsis, ElideComma: true})
}
return
}
if hasStats {
(*s)[len(*s)-1].Comment = (*s)[len(*s)-1].Comment.(diffStats).Append(ds)
}
}
func (s textList) Len() (n int) {
for i, r := range s {
n += len(r.Key)
if r.Key != "" {
n += len(": ")
}
n += r.Value.Len()
if i < len(s)-1 {
n += len(", ")
}
}
return n
}
func (s1 textList) Equal(s2 textNode) bool {
if s2, ok := s2.(textList); ok {
if len(s1) != len(s2) {
return false
}
for i := range s1 {
r1, r2 := s1[i], s2[i]
if !(r1.Diff == r2.Diff && r1.Key == r2.Key && r1.Value.Equal(r2.Value) && r1.Comment == r2.Comment) {
return false
}
}
return true
}
return false
}
func (s textList) String() string {
return (&textWrap{Prefix: "{", Value: s, Suffix: "}"}).String()
}
func (s textList) formatCompactTo(b []byte, d diffMode) ([]byte, textNode) {
s = append(textList(nil), s...) // Avoid mutating original
// Determine whether we can collapse this list as a single line.
n0 := len(b) // Original buffer length
var multiLine bool
for i, r := range s {
if r.Diff == diffInserted || r.Diff == diffRemoved {
multiLine = true
}
b = append(b, r.Key...)
if r.Key != "" {
b = append(b, ": "...)
}
b, s[i].Value = r.Value.formatCompactTo(b, d|r.Diff)
if _, ok := s[i].Value.(textLine); !ok {
multiLine = true
}
if r.Comment != nil {
multiLine = true
}
if i < len(s)-1 {
b = append(b, ", "...)
}
}
// Force multi-lined output when printing a removed/inserted node that
// is sufficiently long.
if (d == diffInserted || d == diffRemoved) && len(b[n0:]) > maxColumnLength {
multiLine = true
}
if !multiLine {
return b, textLine(b[n0:])
}
return b, s
}
func (s textList) formatExpandedTo(b []byte, d diffMode, n indentMode) []byte {
alignKeyLens := s.alignLens(
func(r textRecord) bool {
_, isLine := r.Value.(textLine)
return r.Key == "" || !isLine
},
func(r textRecord) int { return utf8.RuneCountInString(r.Key) },
)
alignValueLens := s.alignLens(
func(r textRecord) bool {
_, isLine := r.Value.(textLine)
return !isLine || r.Value.Equal(textEllipsis) || r.Comment == nil
},
func(r textRecord) int { return utf8.RuneCount(r.Value.(textLine)) },
)
// Format lists of simple lists in a batched form.
// If the list is sequence of only textLine values,
// then batch multiple values on a single line.
var isSimple bool
for _, r := range s {
_, isLine := r.Value.(textLine)
isSimple = r.Diff == 0 && r.Key == "" && isLine && r.Comment == nil
if !isSimple {
break
}
}
if isSimple {
n++
var batch []byte
emitBatch := func() {
if len(batch) > 0 {
b = n.appendIndent(append(b, '\n'), d)
b = append(b, bytes.TrimRight(batch, " ")...)
batch = batch[:0]
}
}
for _, r := range s {
line := r.Value.(textLine)
if len(batch)+len(line)+len(", ") > maxColumnLength {
emitBatch()
}
batch = append(batch, line...)
batch = append(batch, ", "...)
}
emitBatch()
n--
return n.appendIndent(append(b, '\n'), d)
}
// Format the list as a multi-lined output.
n++
for i, r := range s {
b = n.appendIndent(append(b, '\n'), d|r.Diff)
if r.Key != "" {
b = append(b, r.Key+": "...)
}
b = alignKeyLens[i].appendChar(b, ' ')
b = r.Value.formatExpandedTo(b, d|r.Diff, n)
if !r.ElideComma {
b = append(b, ',')
}
b = alignValueLens[i].appendChar(b, ' ')
if r.Comment != nil {
b = append(b, " // "+r.Comment.String()...)
}
}
n--
return n.appendIndent(append(b, '\n'), d)
}
func (s textList) alignLens(
skipFunc func(textRecord) bool,
lenFunc func(textRecord) int,
) []repeatCount {
var startIdx, endIdx, maxLen int
lens := make([]repeatCount, len(s))
for i, r := range s {
if skipFunc(r) {
for j := startIdx; j < endIdx && j < len(s); j++ {
lens[j] = repeatCount(maxLen - lenFunc(s[j]))
}
startIdx, endIdx, maxLen = i+1, i+1, 0
} else {
if maxLen < lenFunc(r) {
maxLen = lenFunc(r)
}
endIdx = i + 1
}
}
for j := startIdx; j < endIdx && j < len(s); j++ {
lens[j] = repeatCount(maxLen - lenFunc(s[j]))
}
return lens
}
// textLine is a single-line segment of text and is always a leaf node
// in the textNode tree.
type textLine []byte
var (
textNil = textLine("nil")
textEllipsis = textLine("...")
)
func (s textLine) Len() int {
return len(s)
}
func (s1 textLine) Equal(s2 textNode) bool {
if s2, ok := s2.(textLine); ok {
return bytes.Equal([]byte(s1), []byte(s2))
}
return false
}
func (s textLine) String() string {
return string(s)
}
func (s textLine) formatCompactTo(b []byte, d diffMode) ([]byte, textNode) {
return append(b, s...), s
}
func (s textLine) formatExpandedTo(b []byte, _ diffMode, _ indentMode) []byte {
return append(b, s...)
}
type diffStats struct {
Name string
NumIgnored int
NumIdentical int
NumRemoved int
NumInserted int
NumModified int
}
func (s diffStats) IsZero() bool {
s.Name = ""
return s == diffStats{}
}
func (s diffStats) NumDiff() int {
return s.NumRemoved + s.NumInserted + s.NumModified
}
func (s diffStats) Append(ds diffStats) diffStats {
assert(s.Name == ds.Name)
s.NumIgnored += ds.NumIgnored
s.NumIdentical += ds.NumIdentical
s.NumRemoved += ds.NumRemoved
s.NumInserted += ds.NumInserted
s.NumModified += ds.NumModified
return s
}
// String prints a humanly-readable summary of coalesced records.
//
// Example:
// diffStats{Name: "Field", NumIgnored: 5}.String() => "5 ignored fields"
func (s diffStats) String() string {
var ss []string
var sum int
labels := [...]string{"ignored", "identical", "removed", "inserted", "modified"}
counts := [...]int{s.NumIgnored, s.NumIdentical, s.NumRemoved, s.NumInserted, s.NumModified}
for i, n := range counts {
if n > 0 {
ss = append(ss, fmt.Sprintf("%d %v", n, labels[i]))
}
sum += n
}
// Pluralize the name (adjusting for some obscure English grammar rules).
name := s.Name
if sum > 1 {
name += "s"
if strings.HasSuffix(name, "ys") {
name = name[:len(name)-2] + "ies" // e.g., "entrys" => "entries"
}
}
// Format the list according to English grammar (with Oxford comma).
switch n := len(ss); n {
case 0:
return ""
case 1, 2:
return strings.Join(ss, " and ") + " " + name
default:
return strings.Join(ss[:n-1], ", ") + ", and " + ss[n-1] + " " + name
}
}
type commentString string
func (s commentString) String() string { return string(s) }