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-rw-r--r--src/fmt/print.go1223
1 files changed, 1223 insertions, 0 deletions
diff --git a/src/fmt/print.go b/src/fmt/print.go
new file mode 100644
index 000000000..59a30d221
--- /dev/null
+++ b/src/fmt/print.go
@@ -0,0 +1,1223 @@
+// Copyright 2009 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 fmt
+
+import (
+ "errors"
+ "io"
+ "os"
+ "reflect"
+ "sync"
+ "unicode/utf8"
+)
+
+// Some constants in the form of bytes, to avoid string overhead.
+// Needlessly fastidious, I suppose.
+var (
+ commaSpaceBytes = []byte(", ")
+ nilAngleBytes = []byte("<nil>")
+ nilParenBytes = []byte("(nil)")
+ nilBytes = []byte("nil")
+ mapBytes = []byte("map[")
+ percentBangBytes = []byte("%!")
+ missingBytes = []byte("(MISSING)")
+ badIndexBytes = []byte("(BADINDEX)")
+ panicBytes = []byte("(PANIC=")
+ extraBytes = []byte("%!(EXTRA ")
+ irparenBytes = []byte("i)")
+ bytesBytes = []byte("[]byte{")
+ badWidthBytes = []byte("%!(BADWIDTH)")
+ badPrecBytes = []byte("%!(BADPREC)")
+ noVerbBytes = []byte("%!(NOVERB)")
+)
+
+// State represents the printer state passed to custom formatters.
+// It provides access to the io.Writer interface plus information about
+// the flags and options for the operand's format specifier.
+type State interface {
+ // Write is the function to call to emit formatted output to be printed.
+ Write(b []byte) (ret int, err error)
+ // Width returns the value of the width option and whether it has been set.
+ Width() (wid int, ok bool)
+ // Precision returns the value of the precision option and whether it has been set.
+ Precision() (prec int, ok bool)
+
+ // Flag reports whether the flag c, a character, has been set.
+ Flag(c int) bool
+}
+
+// Formatter is the interface implemented by values with a custom formatter.
+// The implementation of Format may call Sprint(f) or Fprint(f) etc.
+// to generate its output.
+type Formatter interface {
+ Format(f State, c rune)
+}
+
+// Stringer is implemented by any value that has a String method,
+// which defines the ``native'' format for that value.
+// The String method is used to print values passed as an operand
+// to any format that accepts a string or to an unformatted printer
+// such as Print.
+type Stringer interface {
+ String() string
+}
+
+// GoStringer is implemented by any value that has a GoString method,
+// which defines the Go syntax for that value.
+// The GoString method is used to print values passed as an operand
+// to a %#v format.
+type GoStringer interface {
+ GoString() string
+}
+
+// Use simple []byte instead of bytes.Buffer to avoid large dependency.
+type buffer []byte
+
+func (b *buffer) Write(p []byte) (n int, err error) {
+ *b = append(*b, p...)
+ return len(p), nil
+}
+
+func (b *buffer) WriteString(s string) (n int, err error) {
+ *b = append(*b, s...)
+ return len(s), nil
+}
+
+func (b *buffer) WriteByte(c byte) error {
+ *b = append(*b, c)
+ return nil
+}
+
+func (bp *buffer) WriteRune(r rune) error {
+ if r < utf8.RuneSelf {
+ *bp = append(*bp, byte(r))
+ return nil
+ }
+
+ b := *bp
+ n := len(b)
+ for n+utf8.UTFMax > cap(b) {
+ b = append(b, 0)
+ }
+ w := utf8.EncodeRune(b[n:n+utf8.UTFMax], r)
+ *bp = b[:n+w]
+ return nil
+}
+
+type pp struct {
+ n int
+ panicking bool
+ erroring bool // printing an error condition
+ buf buffer
+ // arg holds the current item, as an interface{}.
+ arg interface{}
+ // value holds the current item, as a reflect.Value, and will be
+ // the zero Value if the item has not been reflected.
+ value reflect.Value
+ // reordered records whether the format string used argument reordering.
+ reordered bool
+ // goodArgNum records whether the most recent reordering directive was valid.
+ goodArgNum bool
+ runeBuf [utf8.UTFMax]byte
+ fmt fmt
+}
+
+var ppFree = sync.Pool{
+ New: func() interface{} { return new(pp) },
+}
+
+// newPrinter allocates a new pp struct or grabs a cached one.
+func newPrinter() *pp {
+ p := ppFree.Get().(*pp)
+ p.panicking = false
+ p.erroring = false
+ p.fmt.init(&p.buf)
+ return p
+}
+
+// free saves used pp structs in ppFree; avoids an allocation per invocation.
+func (p *pp) free() {
+ // Don't hold on to pp structs with large buffers.
+ if cap(p.buf) > 1024 {
+ return
+ }
+ p.buf = p.buf[:0]
+ p.arg = nil
+ p.value = reflect.Value{}
+ ppFree.Put(p)
+}
+
+func (p *pp) Width() (wid int, ok bool) { return p.fmt.wid, p.fmt.widPresent }
+
+func (p *pp) Precision() (prec int, ok bool) { return p.fmt.prec, p.fmt.precPresent }
+
+func (p *pp) Flag(b int) bool {
+ switch b {
+ case '-':
+ return p.fmt.minus
+ case '+':
+ return p.fmt.plus
+ case '#':
+ return p.fmt.sharp
+ case ' ':
+ return p.fmt.space
+ case '0':
+ return p.fmt.zero
+ }
+ return false
+}
+
+func (p *pp) add(c rune) {
+ p.buf.WriteRune(c)
+}
+
+// Implement Write so we can call Fprintf on a pp (through State), for
+// recursive use in custom verbs.
+func (p *pp) Write(b []byte) (ret int, err error) {
+ return p.buf.Write(b)
+}
+
+// These routines end in 'f' and take a format string.
+
+// Fprintf formats according to a format specifier and writes to w.
+// It returns the number of bytes written and any write error encountered.
+func Fprintf(w io.Writer, format string, a ...interface{}) (n int, err error) {
+ p := newPrinter()
+ p.doPrintf(format, a)
+ n, err = w.Write(p.buf)
+ p.free()
+ return
+}
+
+// Printf formats according to a format specifier and writes to standard output.
+// It returns the number of bytes written and any write error encountered.
+func Printf(format string, a ...interface{}) (n int, err error) {
+ return Fprintf(os.Stdout, format, a...)
+}
+
+// Sprintf formats according to a format specifier and returns the resulting string.
+func Sprintf(format string, a ...interface{}) string {
+ p := newPrinter()
+ p.doPrintf(format, a)
+ s := string(p.buf)
+ p.free()
+ return s
+}
+
+// Errorf formats according to a format specifier and returns the string
+// as a value that satisfies error.
+func Errorf(format string, a ...interface{}) error {
+ return errors.New(Sprintf(format, a...))
+}
+
+// These routines do not take a format string
+
+// Fprint formats using the default formats for its operands and writes to w.
+// Spaces are added between operands when neither is a string.
+// It returns the number of bytes written and any write error encountered.
+func Fprint(w io.Writer, a ...interface{}) (n int, err error) {
+ p := newPrinter()
+ p.doPrint(a, false, false)
+ n, err = w.Write(p.buf)
+ p.free()
+ return
+}
+
+// Print formats using the default formats for its operands and writes to standard output.
+// Spaces are added between operands when neither is a string.
+// It returns the number of bytes written and any write error encountered.
+func Print(a ...interface{}) (n int, err error) {
+ return Fprint(os.Stdout, a...)
+}
+
+// Sprint formats using the default formats for its operands and returns the resulting string.
+// Spaces are added between operands when neither is a string.
+func Sprint(a ...interface{}) string {
+ p := newPrinter()
+ p.doPrint(a, false, false)
+ s := string(p.buf)
+ p.free()
+ return s
+}
+
+// These routines end in 'ln', do not take a format string,
+// always add spaces between operands, and add a newline
+// after the last operand.
+
+// Fprintln formats using the default formats for its operands and writes to w.
+// Spaces are always added between operands and a newline is appended.
+// It returns the number of bytes written and any write error encountered.
+func Fprintln(w io.Writer, a ...interface{}) (n int, err error) {
+ p := newPrinter()
+ p.doPrint(a, true, true)
+ n, err = w.Write(p.buf)
+ p.free()
+ return
+}
+
+// Println formats using the default formats for its operands and writes to standard output.
+// Spaces are always added between operands and a newline is appended.
+// It returns the number of bytes written and any write error encountered.
+func Println(a ...interface{}) (n int, err error) {
+ return Fprintln(os.Stdout, a...)
+}
+
+// Sprintln formats using the default formats for its operands and returns the resulting string.
+// Spaces are always added between operands and a newline is appended.
+func Sprintln(a ...interface{}) string {
+ p := newPrinter()
+ p.doPrint(a, true, true)
+ s := string(p.buf)
+ p.free()
+ return s
+}
+
+// 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
+}
+
+// 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++ {
+ num = num*10 + int(s[newi]-'0')
+ isnum = true
+ }
+ return
+}
+
+func (p *pp) unknownType(v reflect.Value) {
+ if !v.IsValid() {
+ p.buf.Write(nilAngleBytes)
+ return
+ }
+ p.buf.WriteByte('?')
+ p.buf.WriteString(v.Type().String())
+ p.buf.WriteByte('?')
+}
+
+func (p *pp) badVerb(verb rune) {
+ p.erroring = true
+ p.add('%')
+ p.add('!')
+ p.add(verb)
+ p.add('(')
+ switch {
+ case p.arg != nil:
+ p.buf.WriteString(reflect.TypeOf(p.arg).String())
+ p.add('=')
+ p.printArg(p.arg, 'v', 0)
+ case p.value.IsValid():
+ p.buf.WriteString(p.value.Type().String())
+ p.add('=')
+ p.printValue(p.value, 'v', 0)
+ default:
+ p.buf.Write(nilAngleBytes)
+ }
+ p.add(')')
+ p.erroring = false
+}
+
+func (p *pp) fmtBool(v bool, verb rune) {
+ switch verb {
+ case 't', 'v':
+ p.fmt.fmt_boolean(v)
+ default:
+ p.badVerb(verb)
+ }
+}
+
+// fmtC formats a rune for the 'c' format.
+func (p *pp) fmtC(c int64) {
+ r := rune(c) // Check for overflow.
+ if int64(r) != c {
+ r = utf8.RuneError
+ }
+ w := utf8.EncodeRune(p.runeBuf[0:utf8.UTFMax], r)
+ p.fmt.pad(p.runeBuf[0:w])
+}
+
+func (p *pp) fmtInt64(v int64, verb rune) {
+ switch verb {
+ case 'b':
+ p.fmt.integer(v, 2, signed, ldigits)
+ case 'c':
+ p.fmtC(v)
+ case 'd', 'v':
+ p.fmt.integer(v, 10, signed, ldigits)
+ case 'o':
+ p.fmt.integer(v, 8, signed, ldigits)
+ case 'q':
+ if 0 <= v && v <= utf8.MaxRune {
+ p.fmt.fmt_qc(v)
+ } else {
+ p.badVerb(verb)
+ }
+ case 'x':
+ p.fmt.integer(v, 16, signed, ldigits)
+ case 'U':
+ p.fmtUnicode(v)
+ case 'X':
+ p.fmt.integer(v, 16, signed, udigits)
+ 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 *pp) fmt0x64(v uint64, leading0x bool) {
+ sharp := p.fmt.sharp
+ p.fmt.sharp = leading0x
+ p.fmt.integer(int64(v), 16, unsigned, ldigits)
+ p.fmt.sharp = sharp
+}
+
+// fmtUnicode formats a uint64 in U+1234 form by
+// temporarily turning on the unicode flag and tweaking the precision.
+func (p *pp) fmtUnicode(v int64) {
+ precPresent := p.fmt.precPresent
+ sharp := p.fmt.sharp
+ p.fmt.sharp = false
+ prec := p.fmt.prec
+ if !precPresent {
+ // If prec is already set, leave it alone; otherwise 4 is minimum.
+ p.fmt.prec = 4
+ p.fmt.precPresent = true
+ }
+ p.fmt.unicode = true // turn on U+
+ p.fmt.uniQuote = sharp
+ p.fmt.integer(int64(v), 16, unsigned, udigits)
+ p.fmt.unicode = false
+ p.fmt.uniQuote = false
+ p.fmt.prec = prec
+ p.fmt.precPresent = precPresent
+ p.fmt.sharp = sharp
+}
+
+func (p *pp) fmtUint64(v uint64, verb rune) {
+ switch verb {
+ case 'b':
+ p.fmt.integer(int64(v), 2, unsigned, ldigits)
+ case 'c':
+ p.fmtC(int64(v))
+ case 'd':
+ p.fmt.integer(int64(v), 10, unsigned, ldigits)
+ case 'v':
+ if p.fmt.sharpV {
+ p.fmt0x64(v, true)
+ } else {
+ p.fmt.integer(int64(v), 10, unsigned, ldigits)
+ }
+ case 'o':
+ p.fmt.integer(int64(v), 8, unsigned, ldigits)
+ case 'q':
+ if 0 <= v && v <= utf8.MaxRune {
+ p.fmt.fmt_qc(int64(v))
+ } else {
+ p.badVerb(verb)
+ }
+ case 'x':
+ p.fmt.integer(int64(v), 16, unsigned, ldigits)
+ case 'X':
+ p.fmt.integer(int64(v), 16, unsigned, udigits)
+ case 'U':
+ p.fmtUnicode(int64(v))
+ default:
+ p.badVerb(verb)
+ }
+}
+
+func (p *pp) fmtFloat32(v float32, verb rune) {
+ switch verb {
+ case 'b':
+ p.fmt.fmt_fb32(v)
+ case 'e':
+ p.fmt.fmt_e32(v)
+ case 'E':
+ p.fmt.fmt_E32(v)
+ case 'f', 'F':
+ p.fmt.fmt_f32(v)
+ case 'g', 'v':
+ p.fmt.fmt_g32(v)
+ case 'G':
+ p.fmt.fmt_G32(v)
+ default:
+ p.badVerb(verb)
+ }
+}
+
+func (p *pp) fmtFloat64(v float64, verb rune) {
+ switch verb {
+ case 'b':
+ p.fmt.fmt_fb64(v)
+ case 'e':
+ p.fmt.fmt_e64(v)
+ case 'E':
+ p.fmt.fmt_E64(v)
+ case 'f', 'F':
+ p.fmt.fmt_f64(v)
+ case 'g', 'v':
+ p.fmt.fmt_g64(v)
+ case 'G':
+ p.fmt.fmt_G64(v)
+ default:
+ p.badVerb(verb)
+ }
+}
+
+func (p *pp) fmtComplex64(v complex64, verb rune) {
+ switch verb {
+ case 'b', 'e', 'E', 'f', 'F', 'g', 'G':
+ p.fmt.fmt_c64(v, verb)
+ case 'v':
+ p.fmt.fmt_c64(v, 'g')
+ default:
+ p.badVerb(verb)
+ }
+}
+
+func (p *pp) fmtComplex128(v complex128, verb rune) {
+ switch verb {
+ case 'b', 'e', 'E', 'f', 'F', 'g', 'G':
+ p.fmt.fmt_c128(v, verb)
+ case 'v':
+ p.fmt.fmt_c128(v, 'g')
+ default:
+ p.badVerb(verb)
+ }
+}
+
+func (p *pp) 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 *pp) fmtBytes(v []byte, verb rune, typ reflect.Type, depth int) {
+ if verb == 'v' || verb == 'd' {
+ if p.fmt.sharpV {
+ if v == nil {
+ if typ == nil {
+ p.buf.WriteString("[]byte(nil)")
+ } else {
+ p.buf.WriteString(typ.String())
+ p.buf.Write(nilParenBytes)
+ }
+ return
+ }
+ if typ == nil {
+ p.buf.Write(bytesBytes)
+ } else {
+ p.buf.WriteString(typ.String())
+ p.buf.WriteByte('{')
+ }
+ } else {
+ p.buf.WriteByte('[')
+ }
+ for i, c := range v {
+ if i > 0 {
+ if p.fmt.sharpV {
+ p.buf.Write(commaSpaceBytes)
+ } else {
+ p.buf.WriteByte(' ')
+ }
+ }
+ p.printArg(c, 'v', depth+1)
+ }
+ if p.fmt.sharpV {
+ p.buf.WriteByte('}')
+ } else {
+ p.buf.WriteByte(']')
+ }
+ return
+ }
+ switch verb {
+ 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.badVerb(verb)
+ }
+}
+
+func (p *pp) fmtPointer(value reflect.Value, verb rune) {
+ use0x64 := true
+ switch verb {
+ case 'p', 'v':
+ // ok
+ case 'b', 'd', 'o', 'x', 'X':
+ use0x64 = false
+ // ok
+ default:
+ p.badVerb(verb)
+ return
+ }
+
+ 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
+ }
+
+ if p.fmt.sharpV {
+ p.add('(')
+ p.buf.WriteString(value.Type().String())
+ p.add(')')
+ p.add('(')
+ if u == 0 {
+ p.buf.Write(nilBytes)
+ } else {
+ p.fmt0x64(uint64(u), true)
+ }
+ p.add(')')
+ } else if verb == 'v' && u == 0 {
+ p.buf.Write(nilAngleBytes)
+ } else {
+ if use0x64 {
+ p.fmt0x64(uint64(u), !p.fmt.sharp)
+ } else {
+ p.fmtUint64(uint64(u), verb)
+ }
+ }
+}
+
+var (
+ intBits = reflect.TypeOf(0).Bits()
+ uintptrBits = reflect.TypeOf(uintptr(0)).Bits()
+)
+
+func (p *pp) 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.buf.Write(nilAngleBytes)
+ 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)
+ }
+ p.fmt.clearflags() // We are done, and for this output we want default behavior.
+ p.buf.Write(percentBangBytes)
+ p.add(verb)
+ p.buf.Write(panicBytes)
+ p.panicking = true
+ p.printArg(err, 'v', 0)
+ p.panicking = false
+ p.buf.WriteByte(')')
+ }
+}
+
+// clearSpecialFlags pushes %#v back into the regular flags and returns their old state.
+func (p *pp) clearSpecialFlags() (plusV, sharpV bool) {
+ plusV = p.fmt.plusV
+ if plusV {
+ p.fmt.plus = true
+ p.fmt.plusV = false
+ }
+ sharpV = p.fmt.sharpV
+ if sharpV {
+ p.fmt.sharp = true
+ p.fmt.sharpV = false
+ }
+ return
+}
+
+// restoreSpecialFlags, whose argument should be a call to clearSpecialFlags,
+// restores the setting of the plusV and sharpV flags.
+func (p *pp) restoreSpecialFlags(plusV, sharpV bool) {
+ if plusV {
+ p.fmt.plus = false
+ p.fmt.plusV = true
+ }
+ if sharpV {
+ p.fmt.sharp = false
+ p.fmt.sharpV = true
+ }
+}
+
+func (p *pp) handleMethods(verb rune, depth int) (handled bool) {
+ if p.erroring {
+ return
+ }
+ // Is it a Formatter?
+ if formatter, ok := p.arg.(Formatter); ok {
+ handled = true
+ defer p.restoreSpecialFlags(p.clearSpecialFlags())
+ 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.(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.printArg(v.Error(), verb, depth)
+ return
+
+ case Stringer:
+ handled = true
+ defer p.catchPanic(p.arg, verb)
+ p.printArg(v.String(), verb, depth)
+ return
+ }
+ }
+ }
+ return false
+}
+
+func (p *pp) printArg(arg interface{}, verb rune, depth int) (wasString bool) {
+ p.arg = arg
+ p.value = reflect.Value{}
+
+ if arg == nil {
+ if verb == 'T' || verb == 'v' {
+ p.fmt.pad(nilAngleBytes)
+ } else {
+ p.badVerb(verb)
+ }
+ return false
+ }
+
+ // Special processing considerations.
+ // %T (the value's type) and %p (its address) are special; we always do them first.
+ switch verb {
+ case 'T':
+ p.printArg(reflect.TypeOf(arg).String(), 's', 0)
+ return false
+ case 'p':
+ p.fmtPointer(reflect.ValueOf(arg), verb)
+ return false
+ }
+
+ // Some types can be done without reflection.
+ switch f := arg.(type) {
+ case bool:
+ p.fmtBool(f, verb)
+ case float32:
+ p.fmtFloat32(f, verb)
+ case float64:
+ p.fmtFloat64(f, verb)
+ case complex64:
+ p.fmtComplex64(f, verb)
+ case complex128:
+ p.fmtComplex128(f, verb)
+ case int:
+ p.fmtInt64(int64(f), verb)
+ case int8:
+ p.fmtInt64(int64(f), verb)
+ case int16:
+ p.fmtInt64(int64(f), verb)
+ case int32:
+ p.fmtInt64(int64(f), verb)
+ case int64:
+ p.fmtInt64(f, verb)
+ case uint:
+ p.fmtUint64(uint64(f), verb)
+ case uint8:
+ p.fmtUint64(uint64(f), verb)
+ case uint16:
+ p.fmtUint64(uint64(f), verb)
+ case uint32:
+ p.fmtUint64(uint64(f), verb)
+ case uint64:
+ p.fmtUint64(f, verb)
+ case uintptr:
+ p.fmtUint64(uint64(f), verb)
+ case string:
+ p.fmtString(f, verb)
+ wasString = verb == 's' || verb == 'v'
+ case []byte:
+ p.fmtBytes(f, verb, nil, depth)
+ wasString = verb == 's'
+ default:
+ // If the type is not simple, it might have methods.
+ if handled := p.handleMethods(verb, depth); handled {
+ return false
+ }
+ // Need to use reflection
+ return p.printReflectValue(reflect.ValueOf(arg), verb, depth)
+ }
+ p.arg = nil
+ return
+}
+
+// printValue is like printArg but starts with a reflect value, not an interface{} value.
+func (p *pp) printValue(value reflect.Value, verb rune, depth int) (wasString bool) {
+ if !value.IsValid() {
+ if verb == 'T' || verb == 'v' {
+ p.buf.Write(nilAngleBytes)
+ } else {
+ p.badVerb(verb)
+ }
+ return false
+ }
+
+ // Special processing considerations.
+ // %T (the value's type) and %p (its address) are special; we always do them first.
+ switch verb {
+ case 'T':
+ p.printArg(value.Type().String(), 's', 0)
+ return false
+ case 'p':
+ p.fmtPointer(value, verb)
+ return false
+ }
+
+ // Handle values with special methods.
+ // Call always, even when arg == nil, because handleMethods clears p.fmt.plus for us.
+ p.arg = nil // Make sure it's cleared, for safety.
+ if value.CanInterface() {
+ p.arg = value.Interface()
+ }
+ if handled := p.handleMethods(verb, depth); handled {
+ return false
+ }
+
+ return p.printReflectValue(value, verb, depth)
+}
+
+var byteType = reflect.TypeOf(byte(0))
+
+// printReflectValue is the fallback for both printArg and printValue.
+// It uses reflect to print the value.
+func (p *pp) printReflectValue(value reflect.Value, verb rune, depth int) (wasString bool) {
+ oldValue := p.value
+ p.value = value
+BigSwitch:
+ switch f := value; f.Kind() {
+ case reflect.Bool:
+ p.fmtBool(f.Bool(), verb)
+ case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+ p.fmtInt64(f.Int(), verb)
+ case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+ p.fmtUint64(f.Uint(), verb)
+ case reflect.Float32, reflect.Float64:
+ if f.Type().Size() == 4 {
+ p.fmtFloat32(float32(f.Float()), verb)
+ } else {
+ p.fmtFloat64(f.Float(), verb)
+ }
+ case reflect.Complex64, reflect.Complex128:
+ if f.Type().Size() == 8 {
+ p.fmtComplex64(complex64(f.Complex()), verb)
+ } else {
+ p.fmtComplex128(f.Complex(), verb)
+ }
+ case reflect.String:
+ p.fmtString(f.String(), verb)
+ case reflect.Map:
+ if p.fmt.sharpV {
+ p.buf.WriteString(f.Type().String())
+ if f.IsNil() {
+ p.buf.WriteString("(nil)")
+ break
+ }
+ p.buf.WriteByte('{')
+ } else {
+ p.buf.Write(mapBytes)
+ }
+ keys := f.MapKeys()
+ for i, key := range keys {
+ if i > 0 {
+ if p.fmt.sharpV {
+ p.buf.Write(commaSpaceBytes)
+ } else {
+ p.buf.WriteByte(' ')
+ }
+ }
+ p.printValue(key, verb, depth+1)
+ p.buf.WriteByte(':')
+ p.printValue(f.MapIndex(key), verb, depth+1)
+ }
+ if p.fmt.sharpV {
+ p.buf.WriteByte('}')
+ } else {
+ p.buf.WriteByte(']')
+ }
+ case reflect.Struct:
+ if p.fmt.sharpV {
+ p.buf.WriteString(value.Type().String())
+ }
+ p.add('{')
+ v := f
+ t := v.Type()
+ for i := 0; i < v.NumField(); i++ {
+ if i > 0 {
+ if p.fmt.sharpV {
+ p.buf.Write(commaSpaceBytes)
+ } else {
+ p.buf.WriteByte(' ')
+ }
+ }
+ if p.fmt.plusV || p.fmt.sharpV {
+ if f := t.Field(i); f.Name != "" {
+ p.buf.WriteString(f.Name)
+ p.buf.WriteByte(':')
+ }
+ }
+ p.printValue(getField(v, i), verb, depth+1)
+ }
+ p.buf.WriteByte('}')
+ case reflect.Interface:
+ value := f.Elem()
+ if !value.IsValid() {
+ if p.fmt.sharpV {
+ p.buf.WriteString(f.Type().String())
+ p.buf.Write(nilParenBytes)
+ } else {
+ p.buf.Write(nilAngleBytes)
+ }
+ } else {
+ wasString = p.printValue(value, verb, depth+1)
+ }
+ case reflect.Array, reflect.Slice:
+ // Byte slices are special:
+ // - Handle []byte (== []uint8) with fmtBytes.
+ // - Handle []T, where T is a named byte type, with fmtBytes only
+ // for the s, q, an x verbs. For other verbs, T might be a
+ // Stringer, so we use printValue to print each element.
+ if typ := f.Type(); typ.Elem().Kind() == reflect.Uint8 && (typ.Elem() == byteType || verb == 's' || verb == 'q' || verb == 'x') {
+ 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, typ, depth)
+ wasString = verb == 's'
+ break
+ }
+ if p.fmt.sharpV {
+ p.buf.WriteString(value.Type().String())
+ if f.Kind() == reflect.Slice && f.IsNil() {
+ p.buf.WriteString("(nil)")
+ break
+ }
+ p.buf.WriteByte('{')
+ } else {
+ p.buf.WriteByte('[')
+ }
+ for i := 0; i < f.Len(); i++ {
+ if i > 0 {
+ if p.fmt.sharpV {
+ p.buf.Write(commaSpaceBytes)
+ } else {
+ p.buf.WriteByte(' ')
+ }
+ }
+ p.printValue(f.Index(i), verb, depth+1)
+ }
+ if p.fmt.sharpV {
+ p.buf.WriteByte('}')
+ } else {
+ p.buf.WriteByte(']')
+ }
+ case reflect.Ptr:
+ v := f.Pointer()
+ // pointer to array or slice or struct? ok at top level
+ // but not embedded (avoid loops)
+ if v != 0 && depth == 0 {
+ switch a := f.Elem(); a.Kind() {
+ case reflect.Array, reflect.Slice:
+ p.buf.WriteByte('&')
+ p.printValue(a, verb, depth+1)
+ break BigSwitch
+ case reflect.Struct:
+ p.buf.WriteByte('&')
+ p.printValue(a, verb, depth+1)
+ break BigSwitch
+ case reflect.Map:
+ p.buf.WriteByte('&')
+ p.printValue(a, verb, depth+1)
+ break BigSwitch
+ }
+ }
+ fallthrough
+ case reflect.Chan, reflect.Func, reflect.UnsafePointer:
+ p.fmtPointer(value, verb)
+ default:
+ p.unknownType(f)
+ }
+ p.value = oldValue
+ return wasString
+}
+
+// intFromArg gets the argNumth element of a. On return, isInt reports whether the argument has type int.
+func intFromArg(a []interface{}, argNum int) (num int, isInt bool, newArgNum int) {
+ newArgNum = argNum
+ if argNum < len(a) {
+ num, isInt = a[argNum].(int)
+ newArgNum = argNum + 1
+ }
+ 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) {
+ // 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
+}
+
+// argNumber 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 *pp) argNumber(argNum int, format string, i int, numArgs int) (newArgNum, newi int, found bool) {
+ if len(format) <= i || format[i] != '[' {
+ return argNum, i, false
+ }
+ p.reordered = true
+ index, wid, ok := parseArgNumber(format[i:])
+ if ok && 0 <= index && index < numArgs {
+ return index, i + wid, true
+ }
+ p.goodArgNum = false
+ return argNum, i + wid, true
+}
+
+func (p *pp) doPrintf(format string, a []interface{}) {
+ end := len(format)
+ argNum := 0 // we process one argument per non-trivial format
+ afterIndex := false // previous item in format was an index like [3].
+ p.reordered = false
+ for i := 0; i < end; {
+ p.goodArgNum = true
+ lasti := i
+ for i < end && format[i] != '%' {
+ i++
+ }
+ if i > lasti {
+ p.buf.WriteString(format[lasti:i])
+ }
+ if i >= end {
+ // done processing format string
+ break
+ }
+
+ // Process one verb
+ i++
+
+ // Do we have flags?
+ p.fmt.clearflags()
+ F:
+ for ; i < end; i++ {
+ switch format[i] {
+ case '#':
+ p.fmt.sharp = true
+ case '0':
+ p.fmt.zero = true
+ case '+':
+ p.fmt.plus = true
+ case '-':
+ p.fmt.minus = true
+ case ' ':
+ p.fmt.space = true
+ default:
+ break F
+ }
+ }
+
+ // Do we have an explicit argument index?
+ argNum, i, afterIndex = p.argNumber(argNum, format, i, len(a))
+
+ // Do we have width?
+ if i < end && format[i] == '*' {
+ i++
+ p.fmt.wid, p.fmt.widPresent, argNum = intFromArg(a, argNum)
+ if !p.fmt.widPresent {
+ p.buf.Write(badWidthBytes)
+ }
+ 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
+ }
+ argNum, i, afterIndex = p.argNumber(argNum, format, i, len(a))
+ if format[i] == '*' {
+ i++
+ p.fmt.prec, p.fmt.precPresent, argNum = intFromArg(a, argNum)
+ if !p.fmt.precPresent {
+ p.buf.Write(badPrecBytes)
+ }
+ 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 {
+ argNum, i, afterIndex = p.argNumber(argNum, format, i, len(a))
+ }
+
+ if i >= end {
+ p.buf.Write(noVerbBytes)
+ continue
+ }
+ c, w := utf8.DecodeRuneInString(format[i:])
+ i += w
+ // percent is special - absorbs no operand
+ if c == '%' {
+ p.buf.WriteByte('%') // We ignore width and prec.
+ continue
+ }
+ if !p.goodArgNum {
+ p.buf.Write(percentBangBytes)
+ p.add(c)
+ p.buf.Write(badIndexBytes)
+ continue
+ } else if argNum >= len(a) { // out of operands
+ p.buf.Write(percentBangBytes)
+ p.add(c)
+ p.buf.Write(missingBytes)
+ continue
+ }
+ arg := a[argNum]
+ argNum++
+
+ if c == 'v' {
+ if p.fmt.sharp {
+ // Go syntax. Set the flag in the fmt and clear the sharp flag.
+ p.fmt.sharp = false
+ p.fmt.sharpV = true
+ }
+ if p.fmt.plus {
+ // Struct-field syntax. Set the flag in the fmt and clear the plus flag.
+ p.fmt.plus = false
+ p.fmt.plusV = true
+ }
+ }
+ p.printArg(arg, c, 0)
+ }
+
+ // Check for extra arguments unless the call accessed the arguments
+ // out of order, in which case it's too expensive to detect if they've all
+ // been used and arguably OK if they're not.
+ if !p.reordered && argNum < len(a) {
+ p.buf.Write(extraBytes)
+ for ; argNum < len(a); argNum++ {
+ arg := a[argNum]
+ if arg != nil {
+ p.buf.WriteString(reflect.TypeOf(arg).String())
+ p.buf.WriteByte('=')
+ }
+ p.printArg(arg, 'v', 0)
+ if argNum+1 < len(a) {
+ p.buf.Write(commaSpaceBytes)
+ }
+ }
+ p.buf.WriteByte(')')
+ }
+}
+
+func (p *pp) doPrint(a []interface{}, addspace, addnewline bool) {
+ prevString := false
+ for argNum := 0; argNum < len(a); argNum++ {
+ p.fmt.clearflags()
+ // always add spaces if we're doing Println
+ arg := a[argNum]
+ if argNum > 0 {
+ isString := arg != nil && reflect.TypeOf(arg).Kind() == reflect.String
+ if addspace || !isString && !prevString {
+ p.buf.WriteByte(' ')
+ }
+ }
+ prevString = p.printArg(arg, 'v', 0)
+ }
+ if addnewline {
+ p.buf.WriteByte('\n')
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-03 04:38:17 +0000