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// Copyright 2017 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 message
import (
"bytes"
"fmt" // TODO: consider copying interfaces from package fmt to avoid dependency.
"math"
"reflect"
"sync"
"unicode/utf8"
"golang.org/x/text/internal/format"
"golang.org/x/text/internal/number"
"golang.org/x/text/language"
"golang.org/x/text/message/catalog"
)
// Strings for use with buffer.WriteString.
// This is less overhead than using buffer.Write with byte arrays.
const (
commaSpaceString = ", "
nilAngleString = "<nil>"
nilParenString = "(nil)"
nilString = "nil"
mapString = "map["
percentBangString = "%!"
missingString = "(MISSING)"
badIndexString = "(BADINDEX)"
panicString = "(PANIC="
extraString = "%!(EXTRA "
badWidthString = "%!(BADWIDTH)"
badPrecString = "%!(BADPREC)"
noVerbString = "%!(NOVERB)"
invReflectString = "<invalid reflect.Value>"
)
var printerPool = sync.Pool{
New: func() interface{} { return new(printer) },
}
// newPrinter allocates a new printer struct or grabs a cached one.
func newPrinter(pp *Printer) *printer {
p := printerPool.Get().(*printer)
p.Printer = *pp
// TODO: cache most of the following call.
p.catContext = pp.cat.Context(pp.tag, p)
p.panicking = false
p.erroring = false
p.fmt.init(&p.Buffer)
return p
}
// free saves used printer structs in printerFree; avoids an allocation per invocation.
func (p *printer) free() {
p.Buffer.Reset()
p.arg = nil
p.value = reflect.Value{}
printerPool.Put(p)
}
// printer is used to store a printer's state.
// It implements "golang.org/x/text/internal/format".State.
type printer struct {
Printer
// the context for looking up message translations
catContext *catalog.Context
// buffer for accumulating output.
bytes.Buffer
// arg holds the current item, as an interface{}.
arg interface{}
// value is used instead of arg for reflect values.
value reflect.Value
// fmt is used to format basic items such as integers or strings.
fmt formatInfo
// panicking is set by catchPanic to avoid infinite panic, recover, panic, ... recursion.
panicking bool
// erroring is set when printing an error string to guard against calling handleMethods.
erroring bool
}
// Language implements "golang.org/x/text/internal/format".State.
func (p *printer) Language() language.Tag { return p.tag }
func (p *printer) Width() (wid int, ok bool) { return p.fmt.Width, p.fmt.WidthPresent }
func (p *printer) Precision() (prec int, ok bool) { return p.fmt.Prec, p.fmt.PrecPresent }
func (p *printer) Flag(b int) bool {
switch b {
case '-':
return p.fmt.Minus
case '+':
return p.fmt.Plus || p.fmt.PlusV
case '#':
return p.fmt.Sharp || p.fmt.SharpV
case ' ':
return p.fmt.Space
case '0':
return p.fmt.Zero
}
return false
}
// getField gets the i'th field of the struct value.
// If the field is itself is an interface, return a value for
// the thing inside the interface, not the interface itself.
func getField(v reflect.Value, i int) reflect.Value {
val := v.Field(i)
if val.Kind() == reflect.Interface && !val.IsNil() {
val = val.Elem()
}
return val
}
func (p *printer) unknownType(v reflect.Value) {
if !v.IsValid() {
p.WriteString(nilAngleString)
return
}
p.WriteByte('?')
p.WriteString(v.Type().String())
p.WriteByte('?')
}
func (p *printer) badVerb(verb rune) {
p.erroring = true
p.WriteString(percentBangString)
p.WriteRune(verb)
p.WriteByte('(')
switch {
case p.arg != nil:
p.WriteString(reflect.TypeOf(p.arg).String())
p.WriteByte('=')
p.printArg(p.arg, 'v')
case p.value.IsValid():
p.WriteString(p.value.Type().String())
p.WriteByte('=')
p.printValue(p.value, 'v', 0)
default:
p.WriteString(nilAngleString)
}
p.WriteByte(')')
p.erroring = false
}
func (p *printer) fmtBool(v bool, verb rune) {
switch verb {
case 't', 'v':
p.fmt.fmt_boolean(v)
default:
p.badVerb(verb)
}
}
// fmt0x64 formats a uint64 in hexadecimal and prefixes it with 0x or
// not, as requested, by temporarily setting the sharp flag.
func (p *printer) fmt0x64(v uint64, leading0x bool) {
sharp := p.fmt.Sharp
p.fmt.Sharp = leading0x
p.fmt.fmt_integer(v, 16, unsigned, ldigits)
p.fmt.Sharp = sharp
}
// fmtInteger formats a signed or unsigned integer.
func (p *printer) fmtInteger(v uint64, isSigned bool, verb rune) {
switch verb {
case 'v':
if p.fmt.SharpV && !isSigned {
p.fmt0x64(v, true)
return
}
fallthrough
case 'd':
if p.fmt.Sharp || p.fmt.SharpV {
p.fmt.fmt_integer(v, 10, isSigned, ldigits)
} else {
p.fmtDecimalInt(v, isSigned)
}
case 'b':
p.fmt.fmt_integer(v, 2, isSigned, ldigits)
case 'o':
p.fmt.fmt_integer(v, 8, isSigned, ldigits)
case 'x':
p.fmt.fmt_integer(v, 16, isSigned, ldigits)
case 'X':
p.fmt.fmt_integer(v, 16, isSigned, udigits)
case 'c':
p.fmt.fmt_c(v)
case 'q':
if v <= utf8.MaxRune {
p.fmt.fmt_qc(v)
} else {
p.badVerb(verb)
}
case 'U':
p.fmt.fmt_unicode(v)
default:
p.badVerb(verb)
}
}
// fmtFloat formats a float. The default precision for each verb
// is specified as last argument in the call to fmt_float.
func (p *printer) fmtFloat(v float64, size int, verb rune) {
switch verb {
case 'b':
p.fmt.fmt_float(v, size, verb, -1)
case 'v':
verb = 'g'
fallthrough
case 'g', 'G':
if p.fmt.Sharp || p.fmt.SharpV {
p.fmt.fmt_float(v, size, verb, -1)
} else {
p.fmtVariableFloat(v, size)
}
case 'e', 'E':
if p.fmt.Sharp || p.fmt.SharpV {
p.fmt.fmt_float(v, size, verb, 6)
} else {
p.fmtScientific(v, size, 6)
}
case 'f', 'F':
if p.fmt.Sharp || p.fmt.SharpV {
p.fmt.fmt_float(v, size, verb, 6)
} else {
p.fmtDecimalFloat(v, size, 6)
}
default:
p.badVerb(verb)
}
}
func (p *printer) setFlags(f *number.Formatter) {
f.Flags &^= number.ElideSign
if p.fmt.Plus || p.fmt.Space {
f.Flags |= number.AlwaysSign
if !p.fmt.Plus {
f.Flags |= number.ElideSign
}
} else {
f.Flags &^= number.AlwaysSign
}
}
func (p *printer) updatePadding(f *number.Formatter) {
f.Flags &^= number.PadMask
if p.fmt.Minus {
f.Flags |= number.PadAfterSuffix
} else {
f.Flags |= number.PadBeforePrefix
}
f.PadRune = ' '
f.FormatWidth = uint16(p.fmt.Width)
}
func (p *printer) initDecimal(minFrac, maxFrac int) {
f := &p.toDecimal
f.MinIntegerDigits = 1
f.MaxIntegerDigits = 0
f.MinFractionDigits = uint8(minFrac)
f.MaxFractionDigits = int16(maxFrac)
p.setFlags(f)
f.PadRune = 0
if p.fmt.WidthPresent {
if p.fmt.Zero {
wid := p.fmt.Width
// Use significant integers for this.
// TODO: this is not the same as width, but so be it.
if f.MinFractionDigits > 0 {
wid -= 1 + int(f.MinFractionDigits)
}
if p.fmt.Plus || p.fmt.Space {
wid--
}
if wid > 0 && wid > int(f.MinIntegerDigits) {
f.MinIntegerDigits = uint8(wid)
}
}
p.updatePadding(f)
}
}
func (p *printer) initScientific(minFrac, maxFrac int) {
f := &p.toScientific
if maxFrac < 0 {
f.SetPrecision(maxFrac)
} else {
f.SetPrecision(maxFrac + 1)
f.MinFractionDigits = uint8(minFrac)
f.MaxFractionDigits = int16(maxFrac)
}
f.MinExponentDigits = 2
p.setFlags(f)
f.PadRune = 0
if p.fmt.WidthPresent {
f.Flags &^= number.PadMask
if p.fmt.Zero {
f.PadRune = f.Digit(0)
f.Flags |= number.PadAfterPrefix
} else {
f.PadRune = ' '
f.Flags |= number.PadBeforePrefix
}
p.updatePadding(f)
}
}
func (p *printer) fmtDecimalInt(v uint64, isSigned bool) {
var d number.Decimal
f := &p.toDecimal
if p.fmt.PrecPresent {
p.setFlags(f)
f.MinIntegerDigits = uint8(p.fmt.Prec)
f.MaxIntegerDigits = 0
f.MinFractionDigits = 0
f.MaxFractionDigits = 0
if p.fmt.WidthPresent {
p.updatePadding(f)
}
} else {
p.initDecimal(0, 0)
}
d.ConvertInt(p.toDecimal.RoundingContext, isSigned, v)
out := p.toDecimal.Format([]byte(nil), &d)
p.Buffer.Write(out)
}
func (p *printer) fmtDecimalFloat(v float64, size, prec int) {
var d number.Decimal
if p.fmt.PrecPresent {
prec = p.fmt.Prec
}
p.initDecimal(prec, prec)
d.ConvertFloat(p.toDecimal.RoundingContext, v, size)
out := p.toDecimal.Format([]byte(nil), &d)
p.Buffer.Write(out)
}
func (p *printer) fmtVariableFloat(v float64, size int) {
prec := -1
if p.fmt.PrecPresent {
prec = p.fmt.Prec
}
var d number.Decimal
p.initScientific(0, prec)
d.ConvertFloat(p.toScientific.RoundingContext, v, size)
// Copy logic of 'g' formatting from strconv. It is simplified a bit as
// we don't have to mind having prec > len(d.Digits).
shortest := prec < 0
ePrec := prec
if shortest {
prec = len(d.Digits)
ePrec = 6
} else if prec == 0 {
prec = 1
ePrec = 1
}
exp := int(d.Exp) - 1
if exp < -4 || exp >= ePrec {
p.initScientific(0, prec)
out := p.toScientific.Format([]byte(nil), &d)
p.Buffer.Write(out)
} else {
if prec > int(d.Exp) {
prec = len(d.Digits)
}
if prec -= int(d.Exp); prec < 0 {
prec = 0
}
p.initDecimal(0, prec)
out := p.toDecimal.Format([]byte(nil), &d)
p.Buffer.Write(out)
}
}
func (p *printer) fmtScientific(v float64, size, prec int) {
var d number.Decimal
if p.fmt.PrecPresent {
prec = p.fmt.Prec
}
p.initScientific(prec, prec)
rc := p.toScientific.RoundingContext
d.ConvertFloat(rc, v, size)
out := p.toScientific.Format([]byte(nil), &d)
p.Buffer.Write(out)
}
// fmtComplex formats a complex number v with
// r = real(v) and j = imag(v) as (r+ji) using
// fmtFloat for r and j formatting.
func (p *printer) fmtComplex(v complex128, size int, verb rune) {
// Make sure any unsupported verbs are found before the
// calls to fmtFloat to not generate an incorrect error string.
switch verb {
case 'v', 'b', 'g', 'G', 'f', 'F', 'e', 'E':
p.WriteByte('(')
p.fmtFloat(real(v), size/2, verb)
// Imaginary part always has a sign.
if math.IsNaN(imag(v)) {
// By CLDR's rules, NaNs do not use patterns or signs. As this code
// relies on AlwaysSign working for imaginary parts, we need to
// manually handle NaNs.
f := &p.toScientific
p.setFlags(f)
p.updatePadding(f)
p.setFlags(f)
nan := f.Symbol(number.SymNan)
extra := 0
if w, ok := p.Width(); ok {
extra = w - utf8.RuneCountInString(nan) - 1
}
if f.Flags&number.PadAfterNumber == 0 {
for ; extra > 0; extra-- {
p.WriteRune(f.PadRune)
}
}
p.WriteString(f.Symbol(number.SymPlusSign))
p.WriteString(nan)
for ; extra > 0; extra-- {
p.WriteRune(f.PadRune)
}
p.WriteString("i)")
return
}
oldPlus := p.fmt.Plus
p.fmt.Plus = true
p.fmtFloat(imag(v), size/2, verb)
p.WriteString("i)") // TODO: use symbol?
p.fmt.Plus = oldPlus
default:
p.badVerb(verb)
}
}
func (p *printer) fmtString(v string, verb rune) {
switch verb {
case 'v':
if p.fmt.SharpV {
p.fmt.fmt_q(v)
} else {
p.fmt.fmt_s(v)
}
case 's':
p.fmt.fmt_s(v)
case 'x':
p.fmt.fmt_sx(v, ldigits)
case 'X':
p.fmt.fmt_sx(v, udigits)
case 'q':
p.fmt.fmt_q(v)
case 'm':
ctx := p.cat.Context(p.tag, rawPrinter{p})
if ctx.Execute(v) == catalog.ErrNotFound {
p.WriteString(v)
}
default:
p.badVerb(verb)
}
}
func (p *printer) fmtBytes(v []byte, verb rune, typeString string) {
switch verb {
case 'v', 'd':
if p.fmt.SharpV {
p.WriteString(typeString)
if v == nil {
p.WriteString(nilParenString)
return
}
p.WriteByte('{')
for i, c := range v {
if i > 0 {
p.WriteString(commaSpaceString)
}
p.fmt0x64(uint64(c), true)
}
p.WriteByte('}')
} else {
p.WriteByte('[')
for i, c := range v {
if i > 0 {
p.WriteByte(' ')
}
p.fmt.fmt_integer(uint64(c), 10, unsigned, ldigits)
}
p.WriteByte(']')
}
case 's':
p.fmt.fmt_s(string(v))
case 'x':
p.fmt.fmt_bx(v, ldigits)
case 'X':
p.fmt.fmt_bx(v, udigits)
case 'q':
p.fmt.fmt_q(string(v))
default:
p.printValue(reflect.ValueOf(v), verb, 0)
}
}
func (p *printer) fmtPointer(value reflect.Value, verb rune) {
var u uintptr
switch value.Kind() {
case reflect.Chan, reflect.Func, reflect.Map, reflect.Ptr, reflect.Slice, reflect.UnsafePointer:
u = value.Pointer()
default:
p.badVerb(verb)
return
}
switch verb {
case 'v':
if p.fmt.SharpV {
p.WriteByte('(')
p.WriteString(value.Type().String())
p.WriteString(")(")
if u == 0 {
p.WriteString(nilString)
} else {
p.fmt0x64(uint64(u), true)
}
p.WriteByte(')')
} else {
if u == 0 {
p.fmt.padString(nilAngleString)
} else {
p.fmt0x64(uint64(u), !p.fmt.Sharp)
}
}
case 'p':
p.fmt0x64(uint64(u), !p.fmt.Sharp)
case 'b', 'o', 'd', 'x', 'X':
if verb == 'd' {
p.fmt.Sharp = true // Print as standard go. TODO: does this make sense?
}
p.fmtInteger(uint64(u), unsigned, verb)
default:
p.badVerb(verb)
}
}
func (p *printer) catchPanic(arg interface{}, verb rune) {
if err := recover(); err != nil {
// If it's a nil pointer, just say "<nil>". The likeliest causes are a
// Stringer that fails to guard against nil or a nil pointer for a
// value receiver, and in either case, "<nil>" is a nice result.
if v := reflect.ValueOf(arg); v.Kind() == reflect.Ptr && v.IsNil() {
p.WriteString(nilAngleString)
return
}
// Otherwise print a concise panic message. Most of the time the panic
// value will print itself nicely.
if p.panicking {
// Nested panics; the recursion in printArg cannot succeed.
panic(err)
}
oldFlags := p.fmt.Parser
// For this output we want default behavior.
p.fmt.ClearFlags()
p.WriteString(percentBangString)
p.WriteRune(verb)
p.WriteString(panicString)
p.panicking = true
p.printArg(err, 'v')
p.panicking = false
p.WriteByte(')')
p.fmt.Parser = oldFlags
}
}
func (p *printer) handleMethods(verb rune) (handled bool) {
if p.erroring {
return
}
// Is it a Formatter?
if formatter, ok := p.arg.(format.Formatter); ok {
handled = true
defer p.catchPanic(p.arg, verb)
formatter.Format(p, verb)
return
}
if formatter, ok := p.arg.(fmt.Formatter); ok {
handled = true
defer p.catchPanic(p.arg, verb)
formatter.Format(p, verb)
return
}
// If we're doing Go syntax and the argument knows how to supply it, take care of it now.
if p.fmt.SharpV {
if stringer, ok := p.arg.(fmt.GoStringer); ok {
handled = true
defer p.catchPanic(p.arg, verb)
// Print the result of GoString unadorned.
p.fmt.fmt_s(stringer.GoString())
return
}
} else {
// If a string is acceptable according to the format, see if
// the value satisfies one of the string-valued interfaces.
// Println etc. set verb to %v, which is "stringable".
switch verb {
case 'v', 's', 'x', 'X', 'q':
// Is it an error or Stringer?
// The duplication in the bodies is necessary:
// setting handled and deferring catchPanic
// must happen before calling the method.
switch v := p.arg.(type) {
case error:
handled = true
defer p.catchPanic(p.arg, verb)
p.fmtString(v.Error(), verb)
return
case fmt.Stringer:
handled = true
defer p.catchPanic(p.arg, verb)
p.fmtString(v.String(), verb)
return
}
}
}
return false
}
func (p *printer) printArg(arg interface{}, verb rune) {
p.arg = arg
p.value = reflect.Value{}
if arg == nil {
switch verb {
case 'T', 'v':
p.fmt.padString(nilAngleString)
default:
p.badVerb(verb)
}
return
}
// Special processing considerations.
// %T (the value's type) and %p (its address) are special; we always do them first.
switch verb {
case 'T':
p.fmt.fmt_s(reflect.TypeOf(arg).String())
return
case 'p':
p.fmtPointer(reflect.ValueOf(arg), 'p')
return
}
// Some types can be done without reflection.
switch f := arg.(type) {
case bool:
p.fmtBool(f, verb)
case float32:
p.fmtFloat(float64(f), 32, verb)
case float64:
p.fmtFloat(f, 64, verb)
case complex64:
p.fmtComplex(complex128(f), 64, verb)
case complex128:
p.fmtComplex(f, 128, verb)
case int:
p.fmtInteger(uint64(f), signed, verb)
case int8:
p.fmtInteger(uint64(f), signed, verb)
case int16:
p.fmtInteger(uint64(f), signed, verb)
case int32:
p.fmtInteger(uint64(f), signed, verb)
case int64:
p.fmtInteger(uint64(f), signed, verb)
case uint:
p.fmtInteger(uint64(f), unsigned, verb)
case uint8:
p.fmtInteger(uint64(f), unsigned, verb)
case uint16:
p.fmtInteger(uint64(f), unsigned, verb)
case uint32:
p.fmtInteger(uint64(f), unsigned, verb)
case uint64:
p.fmtInteger(f, unsigned, verb)
case uintptr:
p.fmtInteger(uint64(f), unsigned, verb)
case string:
p.fmtString(f, verb)
case []byte:
p.fmtBytes(f, verb, "[]byte")
case reflect.Value:
// Handle extractable values with special methods
// since printValue does not handle them at depth 0.
if f.IsValid() && f.CanInterface() {
p.arg = f.Interface()
if p.handleMethods(verb) {
return
}
}
p.printValue(f, verb, 0)
default:
// If the type is not simple, it might have methods.
if !p.handleMethods(verb) {
// Need to use reflection, since the type had no
// interface methods that could be used for formatting.
p.printValue(reflect.ValueOf(f), verb, 0)
}
}
}
// printValue is similar to printArg but starts with a reflect value, not an interface{} value.
// It does not handle 'p' and 'T' verbs because these should have been already handled by printArg.
func (p *printer) printValue(value reflect.Value, verb rune, depth int) {
// Handle values with special methods if not already handled by printArg (depth == 0).
if depth > 0 && value.IsValid() && value.CanInterface() {
p.arg = value.Interface()
if p.handleMethods(verb) {
return
}
}
p.arg = nil
p.value = value
switch f := value; value.Kind() {
case reflect.Invalid:
if depth == 0 {
p.WriteString(invReflectString)
} else {
switch verb {
case 'v':
p.WriteString(nilAngleString)
default:
p.badVerb(verb)
}
}
case reflect.Bool:
p.fmtBool(f.Bool(), verb)
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
p.fmtInteger(uint64(f.Int()), signed, verb)
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
p.fmtInteger(f.Uint(), unsigned, verb)
case reflect.Float32:
p.fmtFloat(f.Float(), 32, verb)
case reflect.Float64:
p.fmtFloat(f.Float(), 64, verb)
case reflect.Complex64:
p.fmtComplex(f.Complex(), 64, verb)
case reflect.Complex128:
p.fmtComplex(f.Complex(), 128, verb)
case reflect.String:
p.fmtString(f.String(), verb)
case reflect.Map:
if p.fmt.SharpV {
p.WriteString(f.Type().String())
if f.IsNil() {
p.WriteString(nilParenString)
return
}
p.WriteByte('{')
} else {
p.WriteString(mapString)
}
keys := f.MapKeys()
for i, key := range keys {
if i > 0 {
if p.fmt.SharpV {
p.WriteString(commaSpaceString)
} else {
p.WriteByte(' ')
}
}
p.printValue(key, verb, depth+1)
p.WriteByte(':')
p.printValue(f.MapIndex(key), verb, depth+1)
}
if p.fmt.SharpV {
p.WriteByte('}')
} else {
p.WriteByte(']')
}
case reflect.Struct:
if p.fmt.SharpV {
p.WriteString(f.Type().String())
}
p.WriteByte('{')
for i := 0; i < f.NumField(); i++ {
if i > 0 {
if p.fmt.SharpV {
p.WriteString(commaSpaceString)
} else {
p.WriteByte(' ')
}
}
if p.fmt.PlusV || p.fmt.SharpV {
if name := f.Type().Field(i).Name; name != "" {
p.WriteString(name)
p.WriteByte(':')
}
}
p.printValue(getField(f, i), verb, depth+1)
}
p.WriteByte('}')
case reflect.Interface:
value := f.Elem()
if !value.IsValid() {
if p.fmt.SharpV {
p.WriteString(f.Type().String())
p.WriteString(nilParenString)
} else {
p.WriteString(nilAngleString)
}
} else {
p.printValue(value, verb, depth+1)
}
case reflect.Array, reflect.Slice:
switch verb {
case 's', 'q', 'x', 'X':
// Handle byte and uint8 slices and arrays special for the above verbs.
t := f.Type()
if t.Elem().Kind() == reflect.Uint8 {
var bytes []byte
if f.Kind() == reflect.Slice {
bytes = f.Bytes()
} else if f.CanAddr() {
bytes = f.Slice(0, f.Len()).Bytes()
} else {
// We have an array, but we cannot Slice() a non-addressable array,
// so we build a slice by hand. This is a rare case but it would be nice
// if reflection could help a little more.
bytes = make([]byte, f.Len())
for i := range bytes {
bytes[i] = byte(f.Index(i).Uint())
}
}
p.fmtBytes(bytes, verb, t.String())
return
}
}
if p.fmt.SharpV {
p.WriteString(f.Type().String())
if f.Kind() == reflect.Slice && f.IsNil() {
p.WriteString(nilParenString)
return
}
p.WriteByte('{')
for i := 0; i < f.Len(); i++ {
if i > 0 {
p.WriteString(commaSpaceString)
}
p.printValue(f.Index(i), verb, depth+1)
}
p.WriteByte('}')
} else {
p.WriteByte('[')
for i := 0; i < f.Len(); i++ {
if i > 0 {
p.WriteByte(' ')
}
p.printValue(f.Index(i), verb, depth+1)
}
p.WriteByte(']')
}
case reflect.Ptr:
// pointer to array or slice or struct? ok at top level
// but not embedded (avoid loops)
if depth == 0 && f.Pointer() != 0 {
switch a := f.Elem(); a.Kind() {
case reflect.Array, reflect.Slice, reflect.Struct, reflect.Map:
p.WriteByte('&')
p.printValue(a, verb, depth+1)
return
}
}
fallthrough
case reflect.Chan, reflect.Func, reflect.UnsafePointer:
p.fmtPointer(f, verb)
default:
p.unknownType(f)
}
}
func (p *printer) badArgNum(verb rune) {
p.WriteString(percentBangString)
p.WriteRune(verb)
p.WriteString(badIndexString)
}
func (p *printer) missingArg(verb rune) {
p.WriteString(percentBangString)
p.WriteRune(verb)
p.WriteString(missingString)
}
func (p *printer) doPrintf(fmt string) {
for p.fmt.Parser.SetFormat(fmt); p.fmt.Scan(); {
switch p.fmt.Status {
case format.StatusText:
p.WriteString(p.fmt.Text())
case format.StatusSubstitution:
p.printArg(p.Arg(p.fmt.ArgNum), p.fmt.Verb)
case format.StatusBadWidthSubstitution:
p.WriteString(badWidthString)
p.printArg(p.Arg(p.fmt.ArgNum), p.fmt.Verb)
case format.StatusBadPrecSubstitution:
p.WriteString(badPrecString)
p.printArg(p.Arg(p.fmt.ArgNum), p.fmt.Verb)
case format.StatusNoVerb:
p.WriteString(noVerbString)
case format.StatusBadArgNum:
p.badArgNum(p.fmt.Verb)
case format.StatusMissingArg:
p.missingArg(p.fmt.Verb)
default:
panic("unreachable")
}
}
// Check for extra arguments, but only if there was at least one ordered
// argument. Note that this behavior is necessarily different from fmt:
// different variants of messages may opt to drop some or all of the
// arguments.
if !p.fmt.Reordered && p.fmt.ArgNum < len(p.fmt.Args) && p.fmt.ArgNum != 0 {
p.fmt.ClearFlags()
p.WriteString(extraString)
for i, arg := range p.fmt.Args[p.fmt.ArgNum:] {
if i > 0 {
p.WriteString(commaSpaceString)
}
if arg == nil {
p.WriteString(nilAngleString)
} else {
p.WriteString(reflect.TypeOf(arg).String())
p.WriteString("=")
p.printArg(arg, 'v')
}
}
p.WriteByte(')')
}
}
func (p *printer) doPrint(a []interface{}) {
prevString := false
for argNum, arg := range a {
isString := arg != nil && reflect.TypeOf(arg).Kind() == reflect.String
// Add a space between two non-string arguments.
if argNum > 0 && !isString && !prevString {
p.WriteByte(' ')
}
p.printArg(arg, 'v')
prevString = isString
}
}
// doPrintln is like doPrint but always adds a space between arguments
// and a newline after the last argument.
func (p *printer) doPrintln(a []interface{}) {
for argNum, arg := range a {
if argNum > 0 {
p.WriteByte(' ')
}
p.printArg(arg, 'v')
}
p.WriteByte('\n')
}