logger/unwrap/unwrap.go

@@ -0,0 +1,535 @@
+package unwrap
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"reflect"
+	"strconv"
+	"strings"
+
+	"go.unistack.org/micro/v3/codec"
+)
+
+const sf = "0-+# "
+
+var hexDigits = "0123456789abcdef"
+
+var (
+	panicBytes         = []byte("(PANIC=")
+	plusBytes          = []byte("+")
+	iBytes             = []byte("i")
+	trueBytes          = []byte("true")
+	falseBytes         = []byte("false")
+	interfaceBytes     = []byte("(interface {})")
+	openBraceBytes     = []byte("{")
+	closeBraceBytes    = []byte("}")
+	asteriskBytes      = []byte("*")
+	ampBytes           = []byte("&")
+	colonBytes         = []byte(":")
+	openParenBytes     = []byte("(")
+	closeParenBytes    = []byte(")")
+	spaceBytes         = []byte(" ")
+	commaBytes         = []byte(",")
+	pointerChainBytes  = []byte("->")
+	nilAngleBytes      = []byte("<nil>")
+	circularShortBytes = []byte("<shown>")
+	invalidAngleBytes  = []byte("<invalid>")
+	openBracketBytes   = []byte("[")
+	closeBracketBytes  = []byte("]")
+	percentBytes       = []byte("%")
+	precisionBytes     = []byte(".")
+	openAngleBytes     = []byte("<")
+	closeAngleBytes    = []byte(">")
+	openMapBytes       = []byte("{")
+	closeMapBytes      = []byte("}")
+)
+
+type unwrap struct {
+	val            interface{}
+	s              fmt.State
+	depth          int
+	pointers       map[uintptr]int
+	opts           *Options
+	ignoreNextType bool
+}
+
+type Options struct {
+	Codec         codec.Codec
+	Indent        string
+	UnwrapMethods bool
+}
+
+func NewOptions(opts ...Option) Options {
+	options := Options{
+		Indent:        " ",
+		UnwrapMethods: false,
+	}
+	for _, o := range opts {
+		o(&options)
+	}
+	return options
+}
+
+type Option func(*Options)
+
+func UnwrapIndent(f string) Option {
+	return func(o *Options) {
+		o.Indent = f
+	}
+}
+
+func UnwrapMethods(b bool) Option {
+	return func(o *Options) {
+		o.UnwrapMethods = b
+	}
+}
+
+func UnwrapCodec(c codec.Codec) Option {
+	return func(o *Options) {
+		o.Codec = c
+	}
+}
+
+func Unwrap(val interface{}, opts ...Option) *unwrap {
+	options := NewOptions(opts...)
+	return &unwrap{val: val, opts: &options, pointers: make(map[uintptr]int)}
+}
+
+func (f *unwrap) unpackValue(v reflect.Value) reflect.Value {
+	if v.Kind() == reflect.Interface {
+		f.ignoreNextType = false
+		if !v.IsNil() {
+			v = v.Elem()
+		}
+	}
+	return v
+}
+
+// formatPtr handles formatting of pointers by indirecting them as necessary.
+func (f *unwrap) formatPtr(v reflect.Value) {
+	// Display nil if top level pointer is nil.
+	showTypes := f.s.Flag('#')
+	if v.IsNil() && (!showTypes || f.ignoreNextType) {
+		_, _ = f.s.Write(nilAngleBytes)
+		return
+	}
+
+	// Remove pointers at or below the current depth from map used to detect
+	// circular refs.
+	for k, depth := range f.pointers {
+		if depth >= f.depth {
+			delete(f.pointers, k)
+		}
+	}
+
+	// Keep list of all dereferenced pointers to possibly show later.
+	pointerChain := make([]uintptr, 0)
+
+	// Figure out how many levels of indirection there are by derferencing
+	// pointers and unpacking interfaces down the chain while detecting circular
+	// references.
+	nilFound := false
+	cycleFound := false
+	indirects := 0
+	ve := v
+	for ve.Kind() == reflect.Ptr {
+		if ve.IsNil() {
+			nilFound = true
+			break
+		}
+		indirects++
+		addr := ve.Pointer()
+		pointerChain = append(pointerChain, addr)
+		if pd, ok := f.pointers[addr]; ok && pd < f.depth {
+			cycleFound = true
+			indirects--
+			break
+		}
+		f.pointers[addr] = f.depth
+
+		ve = ve.Elem()
+		if ve.Kind() == reflect.Interface {
+			if ve.IsNil() {
+				nilFound = true
+				break
+			}
+			ve = ve.Elem()
+		}
+	}
+
+	// Display type or indirection level depending on flags.
+	if showTypes && !f.ignoreNextType {
+		if f.depth > 0 {
+			_, _ = f.s.Write(openParenBytes)
+		}
+		if f.depth > 0 {
+			_, _ = f.s.Write(bytes.Repeat(asteriskBytes, indirects))
+		} else {
+			_, _ = f.s.Write(bytes.Repeat(ampBytes, indirects))
+		}
+
+		_, _ = f.s.Write([]byte(ve.Type().String()))
+
+		if f.depth > 0 {
+			_, _ = f.s.Write(closeParenBytes)
+		}
+	} else {
+		if nilFound || cycleFound {
+			indirects += strings.Count(ve.Type().String(), "*")
+		}
+		_, _ = f.s.Write(openAngleBytes)
+		_, _ = f.s.Write([]byte(strings.Repeat("*", indirects)))
+		_, _ = f.s.Write(closeAngleBytes)
+	}
+
+	// Display pointer information depending on flags.
+	if f.s.Flag('+') && (len(pointerChain) > 0) {
+		_, _ = f.s.Write(openParenBytes)
+		for i, addr := range pointerChain {
+			if i > 0 {
+				_, _ = f.s.Write(pointerChainBytes)
+			}
+			getHexPtr(f.s, addr)
+		}
+		_, _ = f.s.Write(closeParenBytes)
+	}
+
+	// Display dereferenced value.
+	switch {
+	case nilFound:
+		_, _ = f.s.Write(nilAngleBytes)
+
+	case cycleFound:
+		_, _ = f.s.Write(circularShortBytes)
+
+	default:
+		f.ignoreNextType = true
+		f.format(ve)
+	}
+}
+
+// format is the main workhorse for providing the Formatter interface.  It
+// uses the passed reflect value to figure out what kind of object we are
+// dealing with and formats it appropriately.  It is a recursive function,
+// however circular data structures are detected and handled properly.
+func (f *unwrap) format(v reflect.Value) {
+	if f.opts.Codec != nil {
+		buf, err := f.opts.Codec.Marshal(v.Interface())
+		if err != nil {
+			_, _ = f.s.Write(invalidAngleBytes)
+			return
+		}
+		_, _ = f.s.Write(buf)
+		return
+	}
+	// Handle invalid reflect values immediately.
+	kind := v.Kind()
+	if kind == reflect.Invalid {
+		_, _ = f.s.Write(invalidAngleBytes)
+		return
+	}
+
+	// Handle pointers specially.
+	if kind == reflect.Ptr {
+		f.formatPtr(v)
+		return
+	}
+
+	// get type information unless already handled elsewhere.
+	if !f.ignoreNextType && f.s.Flag('#') {
+		if v.Type().Kind() != reflect.Map {
+			_, _ = f.s.Write(openParenBytes)
+		}
+		_, _ = f.s.Write([]byte(v.Type().String()))
+		if v.Type().Kind() != reflect.Map {
+			_, _ = f.s.Write(closeParenBytes)
+		}
+	}
+	f.ignoreNextType = false
+
+	// Call Stringer/error interfaces if they exist and the handle methods
+	// flag is enabled.
+	if !f.opts.UnwrapMethods {
+		if (kind != reflect.Invalid) && (kind != reflect.Interface) {
+			if handled := handleMethods(f.opts, f.s, v); handled {
+				return
+			}
+		}
+	}
+
+	switch kind {
+	case reflect.Invalid:
+		_, _ = f.s.Write(invalidAngleBytes)
+	case reflect.Bool:
+		getBool(f.s, v.Bool())
+	case reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Int:
+		getInt(f.s, v.Int(), 10)
+	case reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uint:
+		getUint(f.s, v.Uint(), 10)
+	case reflect.Float32:
+		getFloat(f.s, v.Float(), 32)
+	case reflect.Float64:
+		getFloat(f.s, v.Float(), 64)
+	case reflect.Complex64:
+		getComplex(f.s, v.Complex(), 32)
+	case reflect.Complex128:
+		getComplex(f.s, v.Complex(), 64)
+	case reflect.Slice:
+		if v.IsNil() {
+			_, _ = f.s.Write(nilAngleBytes)
+			break
+		}
+		fallthrough
+	case reflect.Array:
+		_, _ = f.s.Write(openBracketBytes)
+		f.depth++
+		numEntries := v.Len()
+		for i := 0; i < numEntries; i++ {
+			if i > 0 {
+				_, _ = f.s.Write(spaceBytes)
+			}
+			f.ignoreNextType = true
+			f.format(f.unpackValue(v.Index(i)))
+		}
+		f.depth--
+		_, _ = f.s.Write(closeBracketBytes)
+	case reflect.String:
+		_, _ = f.s.Write([]byte(`"` + v.String() + `"`))
+	case reflect.Interface:
+		// The only time we should get here is for nil interfaces due to
+		// unpackValue calls.
+		if v.IsNil() {
+			_, _ = f.s.Write(nilAngleBytes)
+		}
+	case reflect.Ptr:
+		// Do nothing.  We should never get here since pointers have already
+		// been handled above.
+	case reflect.Map:
+		// nil maps should be indicated as different than empty maps
+		if v.IsNil() {
+			_, _ = f.s.Write(nilAngleBytes)
+			break
+		}
+		_, _ = f.s.Write(openMapBytes)
+		f.depth++
+		keys := v.MapKeys()
+		for i, key := range keys {
+			if i > 0 {
+				_, _ = f.s.Write(spaceBytes)
+			}
+			f.ignoreNextType = true
+			f.format(f.unpackValue(key))
+			_, _ = f.s.Write(colonBytes)
+			f.ignoreNextType = true
+			f.format(f.unpackValue(v.MapIndex(key)))
+		}
+		f.depth--
+		_, _ = f.s.Write(closeMapBytes)
+	case reflect.Struct:
+		numFields := v.NumField()
+		_, _ = f.s.Write(openBraceBytes)
+		f.depth++
+		vt := v.Type()
+		for i := 0; i < numFields; i++ {
+			if i > 0 {
+				_, _ = f.s.Write(commaBytes)
+				_, _ = f.s.Write(spaceBytes)
+			}
+			vtf := vt.Field(i)
+			if f.s.Flag('+') || f.s.Flag('#') {
+				_, _ = f.s.Write([]byte(vtf.Name))
+				_, _ = f.s.Write(colonBytes)
+			}
+			f.format(f.unpackValue(v.Field(i)))
+		}
+		f.depth--
+		_, _ = f.s.Write(closeBraceBytes)
+	case reflect.Uintptr:
+		getHexPtr(f.s, uintptr(v.Uint()))
+	case reflect.UnsafePointer, reflect.Chan, reflect.Func:
+		getHexPtr(f.s, v.Pointer())
+	// There were not any other types at the time this code was written, but
+	// fall back to letting the default fmt package handle it if any get added.
+	default:
+		format := f.buildDefaultFormat()
+		if v.CanInterface() {
+			_, _ = fmt.Fprintf(f.s, format, v.Interface())
+		} else {
+			_, _ = fmt.Fprintf(f.s, format, v.String())
+		}
+	}
+}
+
+func (f *unwrap) Format(s fmt.State, verb rune) {
+	f.s = s
+
+	// Use standard formatting for verbs that are not v.
+	if verb != 'v' {
+		format := f.constructOrigFormat(verb)
+		_, _ = fmt.Fprintf(s, format, f.val)
+		return
+	}
+
+	if f.val == nil {
+		if s.Flag('#') {
+			_, _ = s.Write(interfaceBytes)
+		}
+		_, _ = s.Write(nilAngleBytes)
+		return
+	}
+
+	f.format(reflect.ValueOf(f.val))
+}
+
+// handle special methods like error.Error() or fmt.Stringer interface
+func handleMethods(_ *Options, w io.Writer, v reflect.Value) (handled bool) {
+	if !v.CanInterface() {
+		// not our case
+		return false
+	}
+
+	if !v.CanAddr() {
+		// not our case
+		return false
+	}
+
+	if v.CanAddr() {
+		v = v.Addr()
+	}
+
+	// Is it an error or Stringer?
+	switch iface := v.Interface().(type) {
+	case error:
+		defer catchPanic(w, v)
+		_, _ = w.Write([]byte(iface.Error()))
+		return true
+	case fmt.Stringer:
+		defer catchPanic(w, v)
+		_, _ = w.Write([]byte(iface.String()))
+		return true
+	}
+
+	return false
+}
+
+// getBool outputs a boolean value as true or false to Writer w.
+func getBool(w io.Writer, val bool) {
+	if val {
+		_, _ = w.Write(trueBytes)
+	} else {
+		_, _ = w.Write(falseBytes)
+	}
+}
+
+// getInt outputs a signed integer value to Writer w.
+func getInt(w io.Writer, val int64, base int) {
+	_, _ = w.Write([]byte(strconv.FormatInt(val, base)))
+}
+
+// getUint outputs an unsigned integer value to Writer w.
+func getUint(w io.Writer, val uint64, base int) {
+	_, _ = w.Write([]byte(strconv.FormatUint(val, base)))
+}
+
+// getFloat outputs a floating point value using the specified precision,
+// which is expected to be 32 or 64bit, to Writer w.
+func getFloat(w io.Writer, val float64, precision int) {
+	_, _ = w.Write([]byte(strconv.FormatFloat(val, 'g', -1, precision)))
+}
+
+// getComplex outputs a complex value using the specified float precision
+// for the real and imaginary parts to Writer w.
+func getComplex(w io.Writer, c complex128, floatPrecision int) {
+	r := real(c)
+	_, _ = w.Write(openParenBytes)
+	_, _ = w.Write([]byte(strconv.FormatFloat(r, 'g', -1, floatPrecision)))
+	i := imag(c)
+	if i >= 0 {
+		_, _ = w.Write(plusBytes)
+	}
+	_, _ = w.Write([]byte(strconv.FormatFloat(i, 'g', -1, floatPrecision)))
+	_, _ = w.Write(iBytes)
+	_, _ = w.Write(closeParenBytes)
+}
+
+// getHexPtr outputs a uintptr formatted as hexadecimal with a leading '0x'
+// prefix to Writer w.
+func getHexPtr(w io.Writer, p uintptr) {
+	// Null pointer.
+	num := uint64(p)
+	if num == 0 {
+		_, _ = w.Write(nilAngleBytes)
+		return
+	}
+
+	// Max uint64 is 16 bytes in hex + 2 bytes for '0x' prefix
+	buf := make([]byte, 18)
+
+	// It's simpler to construct the hex string right to left.
+	base := uint64(16)
+	i := len(buf) - 1
+	for num >= base {
+		buf[i] = hexDigits[num%base]
+		num /= base
+		i--
+	}
+	buf[i] = hexDigits[num]
+
+	// Add '0x' prefix.
+	i--
+	buf[i] = 'x'
+	i--
+	buf[i] = '0'
+
+	// Strip unused leading bytes.
+	buf = buf[i:]
+	_, _ = w.Write(buf)
+}
+
+func catchPanic(w io.Writer, _ reflect.Value) {
+	if err := recover(); err != nil {
+		_, _ = w.Write(panicBytes)
+		_, _ = fmt.Fprintf(w, "%v", err)
+		_, _ = w.Write(closeParenBytes)
+	}
+}
+
+func (f *unwrap) buildDefaultFormat() (format string) {
+	buf := bytes.NewBuffer(percentBytes)
+
+	for _, flag := range sf {
+		if f.s.Flag(int(flag)) {
+			_, _ = buf.WriteRune(flag)
+		}
+	}
+
+	_, _ = buf.WriteRune('v')
+
+	format = buf.String()
+	return format
+}
+
+func (f *unwrap) constructOrigFormat(verb rune) (format string) {
+	buf := bytes.NewBuffer(percentBytes)
+
+	for _, flag := range sf {
+		if f.s.Flag(int(flag)) {
+			_, _ = buf.WriteRune(flag)
+		}
+	}
+
+	if width, ok := f.s.Width(); ok {
+		_, _ = buf.WriteString(strconv.Itoa(width))
+	}
+
+	if precision, ok := f.s.Precision(); ok {
+		_, _ = buf.Write(precisionBytes)
+		_, _ = buf.WriteString(strconv.Itoa(precision))
+	}
+
+	_, _ = buf.WriteRune(verb)
+
+	format = buf.String()
+	return format
+}

logger/unwrap/unwrap_test.go

@@ -0,0 +1,46 @@
+package unwrap
+
+import (
+	"testing"
+
+	"go.unistack.org/micro/v3/codec"
+)
+
+func TestUnwrap(t *testing.T) {
+	string1 := "string1"
+	string2 := "string2"
+
+	type val1 struct {
+		mp  map[string]string
+		val *val1
+		str *string
+		ar  []*string
+	}
+
+	v1 := &val1{ar: []*string{&string1, &string2}, str: &string1, val: &val1{str: &string2}, mp: map[string]string{"key": "val"}}
+
+	t.Logf("output: %#v", Unwrap(v1))
+
+	type val2 struct {
+		mp  map[string]string
+		val *val2
+		str string
+		ar  []string
+	}
+
+	v2 := &val2{ar: []string{string1, string2}, str: string1, val: &val2{str: string2}, mp: map[string]string{"key": "val"}}
+
+	t.Logf("output: %#v", v2)
+}
+
+func TestUnwrapCodec(t *testing.T) {
+	type val struct {
+		MP  map[string]string `json:"mp"`
+		STR string            `json:"str"`
+		AR  []string          `json:"ar"`
+	}
+
+	v1 := &val{AR: []string{"string1", "string2"}, STR: "string", MP: map[string]string{"key": "val"}}
+
+	t.Logf("output: %#v", Unwrap(v1, UnwrapCodec(codec.NewCodec())))
+}