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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"
// TODO: consider copying interfaces from package fmt to avoid dependency.
"fmt"
"reflect"
"unicode/utf8"
"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>"
)
// printer is used to store a printer's state.
// It implements "golang.org/x/text/internal/format".State.
type printer struct {
// the context for looking up message translations
catContext *catalog.Context
// the language
tag language.Tag
// buffer for accumulating output.
bytes.Buffer
// retain arguments across calls.
args []interface{}
// retain current argument number across calls
argNum int
// 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
// reordered records whether the format string used argument reordering.
reordered bool
// goodArgNum records whether the most recent reordering directive was valid.
goodArgNum bool
// 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
}
func (p *printer) reset() {
p.Buffer.Reset()
p.argNum = 0
p.reordered = false
p.panicking = false
p.erroring = false
p.fmt.init(&p.Buffer)
}
// 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.wid, p.fmt.widPresent }
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
}
// tooLarge reports whether the magnitude of the integer is
// too large to be used as a formatting width or precision.
func tooLarge(x int) bool {
const max int = 1e6
return x > max || x < -max
}
// parsenum converts ASCII to integer. num is 0 (and isnum is false) if no number present.
func parsenum(s string, start, end int) (num int, isnum bool, newi int) {
if start >= end {
return 0, false, end
}
for newi = start; newi < end && '0' <= s[newi] && s[newi] <= '9'; newi++ {
if tooLarge(num) {
return 0, false, end // Overflow; crazy long number most likely.
}
num = num*10 + int(s[newi]-'0')
isnum = true
}
return
}
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)
} else {
p.fmt.fmt_integer(v, 10, isSigned, ldigits)
}
case 'd':
p.fmt.fmt_integer(v, 10, isSigned, ldigits)
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 'v':
p.fmt.fmt_float(v, size, 'g', -1)
case 'b', 'g', 'G':
p.fmt.fmt_float(v, size, verb, -1)
case 'f', 'e', 'E':
p.fmt.fmt_float(v, size, verb, 6)
case 'F':
p.fmt.fmt_float(v, size, 'f', 6)
default:
p.badVerb(verb)
}
}
// 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':
oldPlus := p.fmt.plus
p.WriteByte('(')
p.fmtFloat(real(v), size/2, verb)
// Imaginary part always has a sign.
p.fmt.plus = true
p.fmtFloat(imag(v), size/2, verb)
p.WriteString("i)")
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)
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':
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.fmtFlags
// 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.fmtFlags = oldFlags
}
}
func (p *printer) handleMethods(verb rune) (handled bool) {
if p.erroring {
return
}
// Is it a Formatter?
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)
}
}
// intFromArg gets the argNumth element of a. On return, isInt reports whether the argument has integer type.
func (p *printer) intFromArg() (num int, isInt bool) {
if p.argNum < len(p.args) {
arg := p.args[p.argNum]
num, isInt = arg.(int) // Almost always OK.
if !isInt {
// Work harder.
switch v := reflect.ValueOf(arg); v.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
n := v.Int()
if int64(int(n)) == n {
num = int(n)
isInt = true
}
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
n := v.Uint()
if int64(n) >= 0 && uint64(int(n)) == n {
num = int(n)
isInt = true
}
default:
// Already 0, false.
}
}
p.argNum++
if tooLarge(num) {
num = 0
isInt = false
}
}
return
}
// parseArgNumber returns the value of the bracketed number, minus 1
// (explicit argument numbers are one-indexed but we want zero-indexed).
// The opening bracket is known to be present at format[0].
// The returned values are the index, the number of bytes to consume
// up to the closing paren, if present, and whether the number parsed
// ok. The bytes to consume will be 1 if no closing paren is present.
func parseArgNumber(format string) (index int, wid int, ok bool) {
// There must be at least 3 bytes: [n].
if len(format) < 3 {
return 0, 1, false
}
// Find closing bracket.
for i := 1; i < len(format); i++ {
if format[i] == ']' {
width, ok, newi := parsenum(format, 1, i)
if !ok || newi != i {
return 0, i + 1, false
}
return width - 1, i + 1, true // arg numbers are one-indexed and skip paren.
}
}
return 0, 1, false
}
// updateArgNumber returns the next argument to evaluate, which is either the value of the passed-in
// argNum or the value of the bracketed integer that begins format[i:]. It also returns
// the new value of i, that is, the index of the next byte of the format to process.
func (p *printer) updateArgNumber(format string, i int) (newi int, found bool) {
if len(format) <= i || format[i] != '[' {
return i, false
}
p.reordered = true
index, wid, ok := parseArgNumber(format[i:])
if ok && 0 <= index && index < len(p.args) {
p.argNum = index
return i + wid, true
}
p.goodArgNum = false
return i + wid, ok
}
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(format string) {
end := len(format)
afterIndex := false // previous item in format was an index like [3].
formatLoop:
for i := 0; i < end; {
p.goodArgNum = true
lasti := i
for i < end && format[i] != '%' {
i++
}
if i > lasti {
p.WriteString(format[lasti:i])
}
if i >= end {
// done processing format string
break
}
// Process one verb
i++
// Do we have flags?
p.fmt.clearflags()
simpleFormat:
for ; i < end; i++ {
c := format[i]
switch c {
case '#':
p.fmt.sharp = true
case '0':
p.fmt.zero = !p.fmt.minus // Only allow zero padding to the left.
case '+':
p.fmt.plus = true
case '-':
p.fmt.minus = true
p.fmt.zero = false // Do not pad with zeros to the right.
case ' ':
p.fmt.space = true
default:
// Fast path for common case of ascii lower case simple verbs
// without precision or width or argument indices.
if 'a' <= c && c <= 'z' && p.argNum < len(p.args) {
if c == 'v' {
// Go syntax
p.fmt.sharpV = p.fmt.sharp
p.fmt.sharp = false
// Struct-field syntax
p.fmt.plusV = p.fmt.plus
p.fmt.plus = false
}
p.printArg(p.Arg(p.argNum), rune(c))
p.argNum++
i++
continue formatLoop
}
// Format is more complex than simple flags and a verb or is malformed.
break simpleFormat
}
}
// Do we have an explicit argument index?
i, afterIndex = p.updateArgNumber(format, i)
// Do we have width?
if i < end && format[i] == '*' {
i++
p.fmt.wid, p.fmt.widPresent = p.intFromArg()
if !p.fmt.widPresent {
p.WriteString(badWidthString)
}
// We have a negative width, so take its value and ensure
// that the minus flag is set
if p.fmt.wid < 0 {
p.fmt.wid = -p.fmt.wid
p.fmt.minus = true
p.fmt.zero = false // Do not pad with zeros to the right.
}
afterIndex = false
} else {
p.fmt.wid, p.fmt.widPresent, i = parsenum(format, i, end)
if afterIndex && p.fmt.widPresent { // "%[3]2d"
p.goodArgNum = false
}
}
// Do we have precision?
if i+1 < end && format[i] == '.' {
i++
if afterIndex { // "%[3].2d"
p.goodArgNum = false
}
i, afterIndex = p.updateArgNumber(format, i)
if i < end && format[i] == '*' {
i++
p.fmt.prec, p.fmt.precPresent = p.intFromArg()
// Negative precision arguments don't make sense
if p.fmt.prec < 0 {
p.fmt.prec = 0
p.fmt.precPresent = false
}
if !p.fmt.precPresent {
p.WriteString(badPrecString)
}
afterIndex = false
} else {
p.fmt.prec, p.fmt.precPresent, i = parsenum(format, i, end)
if !p.fmt.precPresent {
p.fmt.prec = 0
p.fmt.precPresent = true
}
}
}
if !afterIndex {
i, afterIndex = p.updateArgNumber(format, i)
}
if i >= end {
p.WriteString(noVerbString)
break
}
verb, w := utf8.DecodeRuneInString(format[i:])
i += w
switch {
case verb == '%': // Percent does not absorb operands and ignores f.wid and f.prec.
p.WriteByte('%')
case !p.goodArgNum:
p.badArgNum(verb)
case p.argNum >= len(p.args): // No argument left over to print for the current verb.
p.missingArg(verb)
case verb == 'v':
// Go syntax
p.fmt.sharpV = p.fmt.sharp
p.fmt.sharp = false
// Struct-field syntax
p.fmt.plusV = p.fmt.plus
p.fmt.plus = false
fallthrough
default:
p.printArg(p.args[p.argNum], verb)
p.argNum++
}
}
// 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.reordered && p.argNum < len(p.args) && p.argNum != 0 {
p.fmt.clearflags()
p.WriteString(extraString)
for i, arg := range p.args[p.argNum:] {
if i > 0 {
p.WriteString(commaSpaceString)
}
if arg == nil {
p.WriteString(nilAngleString)
} else {
p.WriteString(reflect.TypeOf(arg).String())
p.WriteByte('=')
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')
}