/
Format.go
343 lines (294 loc) · 7.28 KB
/
Format.go
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package pp
import (
"bytes"
"encoding/json"
"fmt"
"github.com/adamluzsi/testcase/internal/reflects"
"io"
"reflect"
"sort"
"strings"
"sync"
"time"
"unicode/utf8"
)
func Format(v any) string {
return formatter{}.Format(v)
}
var (
typeByteSlice = reflect.TypeOf((*[]byte)(nil)).Elem()
typeTimeDuration = reflect.TypeOf((*time.Duration)(nil)).Elem()
typeTimeTime = reflect.TypeOf((*time.Time)(nil)).Elem()
)
type formatter struct{}
func (f formatter) Format(v any) string {
buf := &bytes.Buffer{}
rv := reflect.ValueOf(v)
vis := &visitor{}
vis.Visit(buf, rv, 0)
if vis.isStackoverflow() {
return fmt.Sprintf("%#v", v)
}
return buf.String()
}
type visitor struct {
visitedInit sync.Once
visited map[reflect.Value]struct{}
stack int
}
func (v *visitor) Visit(w io.Writer, rv reflect.Value, depth int) {
defer debugRecover()
td, ok := v.recursionGuard(w, rv)
if !ok {
return
}
defer td()
if rv.Kind() == reflect.Invalid {
_, _ = fmt.Fprint(w, "nil")
return
}
rv = reflects.Accessible(rv)
if rv.Type() == typeTimeDuration {
d := time.Duration(rv.Int())
_, _ = fmt.Fprintf(w, "/* %s */ %#v", d.String(), d)
return
}
if rv.Type() == typeTimeTime {
_, _ = fmt.Fprintf(w, "%#v", rv.Interface())
return
}
if v.tryStringer(w, rv, depth) {
return
}
if rv.CanInt() {
_, _ = fmt.Fprintf(w, "%#v", rv.Int())
return
}
if rv.CanUint() {
_, _ = fmt.Fprintf(w, "%d", rv.Uint())
return
}
if rv.CanFloat() {
_, _ = fmt.Fprintf(w, "%#v", rv.Float())
return
}
switch rv.Kind() {
case reflect.Array, reflect.Slice:
if v.tryNilSlice(w, rv) {
return
}
if v.tryByteSlice(w, rv, depth) {
return
}
_, _ = fmt.Fprintf(w, "%s{", v.getTypeName(rv))
vLen := rv.Len()
for i := 0; i < vLen; i++ {
v.newLine(w, depth+1)
v.Visit(w, rv.Index(i), depth+1)
_, _ = fmt.Fprintf(w, ",")
}
if 0 < vLen {
v.newLine(w, depth)
}
_, _ = fmt.Fprint(w, "}")
case reflect.Map:
_, _ = fmt.Fprintf(w, "%s{", v.getTypeName(rv))
keys := rv.MapKeys()
v.sortMapKeys(keys)
for _, key := range keys {
v.newLine(w, depth+1)
v.Visit(w, key, depth+1) // key
_, _ = fmt.Fprintf(w, ": ")
v.Visit(w, rv.MapIndex(key), depth+1) // value
_, _ = fmt.Fprintf(w, ",")
}
if 0 < len(keys) {
v.newLine(w, depth)
}
_, _ = fmt.Fprint(w, "}")
case reflect.Struct:
v.visitStructure(w, rv, depth)
case reflect.Interface:
_, _ = fmt.Fprintf(w, "(%s)(", v.getTypeName(rv))
v.Visit(w, rv.Elem(), depth)
_, _ = fmt.Fprint(w, ")")
case reflect.Pointer:
if rv.IsNil() {
v.Visit(w, reflect.ValueOf(nil), depth)
return
}
elem := rv.Elem()
if v.isRecursion(elem) {
_, _ = fmt.Fprintf(w, "(%s)(", v.getTypeName(rv))
_, _ = fmt.Fprintf(w, "%#v", rv.Pointer())
_, _ = fmt.Fprint(w, ")")
return
}
_, _ = fmt.Fprintf(w, "&")
v.Visit(w, rv.Elem(), depth)
case reflect.Chan:
_, _ = fmt.Fprintf(w, "make(%s, %d)", rv.Type().String(), rv.Cap())
case reflect.String:
_, _ = fmt.Fprintf(w, "%#v", rv.String())
default:
v, ok := reflects.TryToMakeAccessible(rv)
if !ok {
_, _ = fmt.Fprint(w, "/* inaccessible */")
return
}
_, _ = fmt.Fprintf(w, "%#v", v.Interface())
}
}
func (v *visitor) recursionGuard(w io.Writer, rv reflect.Value) (_td func(), _ok bool) {
v.stack++
if v.isStackoverflow() {
return
}
v.visitedInit.Do(func() { v.visited = make(map[reflect.Value]struct{}) })
if !v.isRecursion(rv) {
v.visited[rv] = struct{}{}
return func() { delete(v.visited, rv) }, true
}
if rv.CanAddr() {
_, _ = fmt.Fprintf(w, "%#v", rv.UnsafeAddr())
} else if rv.CanInterface() {
_, _ = fmt.Fprintf(w, "%#v", rv.Interface())
} else {
_, _ = fmt.Fprintf(w, "%v", rv)
}
return func() {}, false
}
func (v *visitor) isStackoverflow() bool {
return 256 < v.stack
}
func (v *visitor) isRecursion(rv reflect.Value) bool {
if v.visited == nil {
return false
}
_, ok := v.visited[rv]
return ok
}
func (v *visitor) isEmpty(rv reflect.Value) bool {
if v.isNil(rv) {
return true
}
switch rv.Kind() {
case reflect.Chan, reflect.Map, reflect.Slice:
return rv.Len() == 0
case reflect.Array:
zero := reflect.New(rv.Type()).Elem().Interface()
return reflect.DeepEqual(zero, rv)
case reflect.Ptr:
if rv.IsNil() {
return true
}
return v.isEmpty(rv.Elem())
default:
return reflect.DeepEqual(reflect.Zero(rv.Type()).Interface(), rv)
}
}
func (v *visitor) isNil(rv reflect.Value) bool {
defer func() { _ = recover() }()
if rv.CanInterface() && rv.Interface() == nil {
return true
}
return rv.IsNil()
}
var fmtStringerType = reflect.TypeOf((*fmt.Stringer)(nil)).Elem()
func (v *visitor) tryStringer(w io.Writer, rv reflect.Value, depth int) bool {
if !rv.Type().Implements(fmtStringerType) {
return false
}
_, _ = fmt.Fprintf(w, "/* %s */ ", rv.Type().String())
v.Visit(w, rv.MethodByName("String").Call([]reflect.Value{})[0], depth)
return true
}
func (v *visitor) visitStructure(w io.Writer, rv reflect.Value, depth int) {
_, _ = fmt.Fprintf(w, "%s{", rv.Type().String())
fieldNum := rv.NumField()
for i, fNum := 0, fieldNum; i < fNum; i++ {
name := rv.Type().Field(i).Name
field := rv.FieldByName(name)
v.newLine(w, depth+1)
_, _ = fmt.Fprintf(w, "%s: ", name)
v.Visit(w, field, depth+1)
_, _ = fmt.Fprintf(w, ",")
}
if 0 < fieldNum {
v.newLine(w, depth)
}
_, _ = fmt.Fprint(w, "}")
}
func (v *visitor) newLine(w io.Writer, depth int) {
_, _ = w.Write([]byte("\n"))
_, _ = w.Write([]byte(v.indent(depth)))
}
func (v *visitor) indent(depth int) string {
const defaultIndent = "\t"
return strings.Repeat(defaultIndent, depth)
}
func (v *visitor) sortMapKeys(keys []reflect.Value) {
if 0 == len(keys) {
return
}
kind := keys[0].Kind()
sort.Slice(keys, func(i, j int) bool {
switch kind {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return keys[i].Int() < keys[j].Int()
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
return keys[i].Uint() < keys[j].Uint()
case reflect.Float32, reflect.Float64:
return keys[i].Float() < keys[j].Float()
case reflect.String:
return keys[i].String() < keys[j].String()
default:
return Format(keys[i]) < Format(keys[j])
}
})
}
func (v *visitor) tryByteSlice(w io.Writer, rv reflect.Value, depth int) bool {
if !rv.Type().ConvertibleTo(typeByteSlice) {
return false
}
var data = rv.Convert(typeByteSlice).Bytes()
if !utf8.Valid(data) {
return false
}
if json.Valid(data) {
var buf bytes.Buffer
if err := json.Indent(&buf, data, v.indent(depth), "\t"); err == nil {
data = buf.Bytes()
}
}
var (
typeName = v.getTypeName(rv)
quoteChar = "`"
content = string(data)
)
switch {
case !strings.Contains(content, `"`):
quoteChar = `"`
case !strings.Contains(content, "`"):
quoteChar = "`"
default:
quoteChar = "`"
content = strings.ReplaceAll(content, "`", "`+\"`\"+`")
}
_, _ = fmt.Fprintf(w, "%s(%s%s%s)", typeName, quoteChar, content, quoteChar)
return true
}
func (v *visitor) getTypeName(rv reflect.Value) string {
var typeName = rv.Type().String()
if rv.Type() == typeByteSlice {
typeName = "[]byte"
}
return typeName
}
func (v *visitor) tryNilSlice(w io.Writer, rv reflect.Value) bool {
if rv.Kind() != reflect.Slice || !rv.IsNil() {
return false
}
_, _ = fmt.Fprintf(w, "(%s)(nil)", rv.Type().String())
return true
}