peridot/vendor/github.com/google/go-cmp/cmp/report_reflect.go

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2022-07-07 20:11:50 +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 file.
package cmp
import (
"bytes"
"fmt"
"reflect"
"strconv"
"strings"
"unicode"
"unicode/utf8"
"github.com/google/go-cmp/cmp/internal/value"
)
type formatValueOptions struct {
// AvoidStringer controls whether to avoid calling custom stringer
// methods like error.Error or fmt.Stringer.String.
AvoidStringer bool
// PrintAddresses controls whether to print the address of all pointers,
// slice elements, and maps.
PrintAddresses bool
// QualifiedNames controls whether FormatType uses the fully qualified name
// (including the full package path as opposed to just the package name).
QualifiedNames bool
// VerbosityLevel controls the amount of output to produce.
// A higher value produces more output. A value of zero or lower produces
// no output (represented using an ellipsis).
// If LimitVerbosity is false, then the level is treated as infinite.
VerbosityLevel int
// LimitVerbosity specifies that formatting should respect VerbosityLevel.
LimitVerbosity bool
}
// FormatType prints the type as if it were wrapping s.
// This may return s as-is depending on the current type and TypeMode mode.
func (opts formatOptions) FormatType(t reflect.Type, s textNode) textNode {
// Check whether to emit the type or not.
switch opts.TypeMode {
case autoType:
switch t.Kind() {
case reflect.Struct, reflect.Slice, reflect.Array, reflect.Map:
if s.Equal(textNil) {
return s
}
default:
return s
}
if opts.DiffMode == diffIdentical {
return s // elide type for identical nodes
}
case elideType:
return s
}
// Determine the type label, applying special handling for unnamed types.
typeName := value.TypeString(t, opts.QualifiedNames)
if t.Name() == "" {
// According to Go grammar, certain type literals contain symbols that
// do not strongly bind to the next lexicographical token (e.g., *T).
switch t.Kind() {
case reflect.Chan, reflect.Func, reflect.Ptr:
typeName = "(" + typeName + ")"
}
}
return &textWrap{Prefix: typeName, Value: wrapParens(s)}
}
// wrapParens wraps s with a set of parenthesis, but avoids it if the
// wrapped node itself is already surrounded by a pair of parenthesis or braces.
// It handles unwrapping one level of pointer-reference nodes.
func wrapParens(s textNode) textNode {
var refNode *textWrap
if s2, ok := s.(*textWrap); ok {
// Unwrap a single pointer reference node.
switch s2.Metadata.(type) {
case leafReference, trunkReference, trunkReferences:
refNode = s2
if s3, ok := refNode.Value.(*textWrap); ok {
s2 = s3
}
}
// Already has delimiters that make parenthesis unnecessary.
hasParens := strings.HasPrefix(s2.Prefix, "(") && strings.HasSuffix(s2.Suffix, ")")
hasBraces := strings.HasPrefix(s2.Prefix, "{") && strings.HasSuffix(s2.Suffix, "}")
if hasParens || hasBraces {
return s
}
}
if refNode != nil {
refNode.Value = &textWrap{Prefix: "(", Value: refNode.Value, Suffix: ")"}
return s
}
return &textWrap{Prefix: "(", Value: s, Suffix: ")"}
}
// FormatValue prints the reflect.Value, taking extra care to avoid descending
// into pointers already in ptrs. As pointers are visited, ptrs is also updated.
func (opts formatOptions) FormatValue(v reflect.Value, parentKind reflect.Kind, ptrs *pointerReferences) (out textNode) {
if !v.IsValid() {
return nil
}
t := v.Type()
// Check slice element for cycles.
if parentKind == reflect.Slice {
ptrRef, visited := ptrs.Push(v.Addr())
if visited {
return makeLeafReference(ptrRef, false)
}
defer ptrs.Pop()
defer func() { out = wrapTrunkReference(ptrRef, false, out) }()
}
// Check whether there is an Error or String method to call.
if !opts.AvoidStringer && v.CanInterface() {
// Avoid calling Error or String methods on nil receivers since many
// implementations crash when doing so.
if (t.Kind() != reflect.Ptr && t.Kind() != reflect.Interface) || !v.IsNil() {
var prefix, strVal string
func() {
// Swallow and ignore any panics from String or Error.
defer func() { recover() }()
switch v := v.Interface().(type) {
case error:
strVal = v.Error()
prefix = "e"
case fmt.Stringer:
strVal = v.String()
prefix = "s"
}
}()
if prefix != "" {
return opts.formatString(prefix, strVal)
}
}
}
// Check whether to explicitly wrap the result with the type.
var skipType bool
defer func() {
if !skipType {
out = opts.FormatType(t, out)
}
}()
switch t.Kind() {
case reflect.Bool:
return textLine(fmt.Sprint(v.Bool()))
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return textLine(fmt.Sprint(v.Int()))
case reflect.Uint, reflect.Uint16, reflect.Uint32, reflect.Uint64:
return textLine(fmt.Sprint(v.Uint()))
case reflect.Uint8:
if parentKind == reflect.Slice || parentKind == reflect.Array {
return textLine(formatHex(v.Uint()))
}
return textLine(fmt.Sprint(v.Uint()))
case reflect.Uintptr:
return textLine(formatHex(v.Uint()))
case reflect.Float32, reflect.Float64:
return textLine(fmt.Sprint(v.Float()))
case reflect.Complex64, reflect.Complex128:
return textLine(fmt.Sprint(v.Complex()))
case reflect.String:
return opts.formatString("", v.String())
case reflect.UnsafePointer, reflect.Chan, reflect.Func:
return textLine(formatPointer(value.PointerOf(v), true))
case reflect.Struct:
var list textList
v := makeAddressable(v) // needed for retrieveUnexportedField
maxLen := v.NumField()
if opts.LimitVerbosity {
maxLen = ((1 << opts.verbosity()) >> 1) << 2 // 0, 4, 8, 16, 32, etc...
opts.VerbosityLevel--
}
for i := 0; i < v.NumField(); i++ {
vv := v.Field(i)
if value.IsZero(vv) {
continue // Elide fields with zero values
}
if len(list) == maxLen {
list.AppendEllipsis(diffStats{})
break
}
sf := t.Field(i)
if supportExporters && !isExported(sf.Name) {
vv = retrieveUnexportedField(v, sf, true)
}
s := opts.WithTypeMode(autoType).FormatValue(vv, t.Kind(), ptrs)
list = append(list, textRecord{Key: sf.Name, Value: s})
}
return &textWrap{Prefix: "{", Value: list, Suffix: "}"}
case reflect.Slice:
if v.IsNil() {
return textNil
}
// Check whether this is a []byte of text data.
if t.Elem() == reflect.TypeOf(byte(0)) {
b := v.Bytes()
isPrintSpace := func(r rune) bool { return unicode.IsPrint(r) || unicode.IsSpace(r) }
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if len(b) > 0 && utf8.Valid(b) && len(bytes.TrimFunc(b, isPrintSpace)) == 0 {
out = opts.formatString("", string(b))
skipType = true
return opts.FormatType(t, out)
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}
}
fallthrough
case reflect.Array:
maxLen := v.Len()
if opts.LimitVerbosity {
maxLen = ((1 << opts.verbosity()) >> 1) << 2 // 0, 4, 8, 16, 32, etc...
opts.VerbosityLevel--
}
var list textList
for i := 0; i < v.Len(); i++ {
if len(list) == maxLen {
list.AppendEllipsis(diffStats{})
break
}
s := opts.WithTypeMode(elideType).FormatValue(v.Index(i), t.Kind(), ptrs)
list = append(list, textRecord{Value: s})
}
out = &textWrap{Prefix: "{", Value: list, Suffix: "}"}
if t.Kind() == reflect.Slice && opts.PrintAddresses {
header := fmt.Sprintf("ptr:%v, len:%d, cap:%d", formatPointer(value.PointerOf(v), false), v.Len(), v.Cap())
out = &textWrap{Prefix: pointerDelimPrefix + header + pointerDelimSuffix, Value: out}
}
return out
case reflect.Map:
if v.IsNil() {
return textNil
}
// Check pointer for cycles.
ptrRef, visited := ptrs.Push(v)
if visited {
return makeLeafReference(ptrRef, opts.PrintAddresses)
}
defer ptrs.Pop()
maxLen := v.Len()
if opts.LimitVerbosity {
maxLen = ((1 << opts.verbosity()) >> 1) << 2 // 0, 4, 8, 16, 32, etc...
opts.VerbosityLevel--
}
var list textList
for _, k := range value.SortKeys(v.MapKeys()) {
if len(list) == maxLen {
list.AppendEllipsis(diffStats{})
break
}
sk := formatMapKey(k, false, ptrs)
sv := opts.WithTypeMode(elideType).FormatValue(v.MapIndex(k), t.Kind(), ptrs)
list = append(list, textRecord{Key: sk, Value: sv})
}
out = &textWrap{Prefix: "{", Value: list, Suffix: "}"}
out = wrapTrunkReference(ptrRef, opts.PrintAddresses, out)
return out
case reflect.Ptr:
if v.IsNil() {
return textNil
}
// Check pointer for cycles.
ptrRef, visited := ptrs.Push(v)
if visited {
out = makeLeafReference(ptrRef, opts.PrintAddresses)
return &textWrap{Prefix: "&", Value: out}
}
defer ptrs.Pop()
// Skip the name only if this is an unnamed pointer type.
// Otherwise taking the address of a value does not reproduce
// the named pointer type.
if v.Type().Name() == "" {
skipType = true // Let the underlying value print the type instead
}
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out = opts.FormatValue(v.Elem(), t.Kind(), ptrs)
out = wrapTrunkReference(ptrRef, opts.PrintAddresses, out)
out = &textWrap{Prefix: "&", Value: out}
return out
case reflect.Interface:
if v.IsNil() {
return textNil
}
// Interfaces accept different concrete types,
// so configure the underlying value to explicitly print the type.
return opts.WithTypeMode(emitType).FormatValue(v.Elem(), t.Kind(), ptrs)
default:
panic(fmt.Sprintf("%v kind not handled", v.Kind()))
}
}
func (opts formatOptions) formatString(prefix, s string) textNode {
maxLen := len(s)
maxLines := strings.Count(s, "\n") + 1
if opts.LimitVerbosity {
maxLen = (1 << opts.verbosity()) << 5 // 32, 64, 128, 256, etc...
maxLines = (1 << opts.verbosity()) << 2 // 4, 8, 16, 32, 64, etc...
}
// For multiline strings, use the triple-quote syntax,
// but only use it when printing removed or inserted nodes since
// we only want the extra verbosity for those cases.
lines := strings.Split(strings.TrimSuffix(s, "\n"), "\n")
isTripleQuoted := len(lines) >= 4 && (opts.DiffMode == '-' || opts.DiffMode == '+')
for i := 0; i < len(lines) && isTripleQuoted; i++ {
lines[i] = strings.TrimPrefix(strings.TrimSuffix(lines[i], "\r"), "\r") // trim leading/trailing carriage returns for legacy Windows endline support
isPrintable := func(r rune) bool {
return unicode.IsPrint(r) || r == '\t' // specially treat tab as printable
}
line := lines[i]
isTripleQuoted = !strings.HasPrefix(strings.TrimPrefix(line, prefix), `"""`) && !strings.HasPrefix(line, "...") && strings.TrimFunc(line, isPrintable) == "" && len(line) <= maxLen
}
if isTripleQuoted {
var list textList
list = append(list, textRecord{Diff: opts.DiffMode, Value: textLine(prefix + `"""`), ElideComma: true})
for i, line := range lines {
if numElided := len(lines) - i; i == maxLines-1 && numElided > 1 {
comment := commentString(fmt.Sprintf("%d elided lines", numElided))
list = append(list, textRecord{Diff: opts.DiffMode, Value: textEllipsis, ElideComma: true, Comment: comment})
break
}
list = append(list, textRecord{Diff: opts.DiffMode, Value: textLine(line), ElideComma: true})
}
list = append(list, textRecord{Diff: opts.DiffMode, Value: textLine(prefix + `"""`), ElideComma: true})
return &textWrap{Prefix: "(", Value: list, Suffix: ")"}
}
// Format the string as a single-line quoted string.
if len(s) > maxLen+len(textEllipsis) {
return textLine(prefix + formatString(s[:maxLen]) + string(textEllipsis))
}
return textLine(prefix + formatString(s))
}
// formatMapKey formats v as if it were a map key.
// The result is guaranteed to be a single line.
func formatMapKey(v reflect.Value, disambiguate bool, ptrs *pointerReferences) string {
var opts formatOptions
opts.DiffMode = diffIdentical
opts.TypeMode = elideType
opts.PrintAddresses = disambiguate
opts.AvoidStringer = disambiguate
opts.QualifiedNames = disambiguate
opts.VerbosityLevel = maxVerbosityPreset
opts.LimitVerbosity = true
s := opts.FormatValue(v, reflect.Map, ptrs).String()
return strings.TrimSpace(s)
}
// formatString prints s as a double-quoted or backtick-quoted string.
func formatString(s string) string {
// Use quoted string if it the same length as a raw string literal.
// Otherwise, attempt to use the raw string form.
qs := strconv.Quote(s)
if len(qs) == 1+len(s)+1 {
return qs
}
// Disallow newlines to ensure output is a single line.
// Only allow printable runes for readability purposes.
rawInvalid := func(r rune) bool {
return r == '`' || r == '\n' || !(unicode.IsPrint(r) || r == '\t')
}
if utf8.ValidString(s) && strings.IndexFunc(s, rawInvalid) < 0 {
return "`" + s + "`"
}
return qs
}
// formatHex prints u as a hexadecimal integer in Go notation.
func formatHex(u uint64) string {
var f string
switch {
case u <= 0xff:
f = "0x%02x"
case u <= 0xffff:
f = "0x%04x"
case u <= 0xffffff:
f = "0x%06x"
case u <= 0xffffffff:
f = "0x%08x"
case u <= 0xffffffffff:
f = "0x%010x"
case u <= 0xffffffffffff:
f = "0x%012x"
case u <= 0xffffffffffffff:
f = "0x%014x"
case u <= 0xffffffffffffffff:
f = "0x%016x"
}
return fmt.Sprintf(f, u)
}