Initial commit

vendor/github.com/cockroachdb/redact/internal/README.md

@@ -0,0 +1,52 @@
+Overall code structure
+======================
+
+This directory imports the "printf" logic as-is from the Go standard
+library and instruments it for redaction of sensitive data.
+
+Overall, the original Go code is structured as follows:
+
+- the top-level API functions (`Printf` `Fprintf` etc) instantiate a
+  "printer" struct called `pp`, then call the `doPrint*()` methods
+  on it.
+
+- the `pp` contains a byte slice (`pp.buf`, type `buffer`) that
+  accumulates the result of formatting *regardless of the final output
+  of the API* - i.e. a buffer is used even when using `Fprint` to an
+  `io.Writer`. Only after the `doPrint()` method finishes, is the
+  `buffer` copied to the final `io.Writer` in the `Fprint*` variants.
+
+- each of the `doPrint` methods does some analysis on the argument
+  list - quite simple for e.g. `doPrintln`, more intricate for
+  `doPrintf`.  As part of the analysis it emits "spacing" or no-op
+  bytes directly on the `pp.buf`. For example `doPrint` emits spaces
+  between arguments directly, `doPrintf` emits the non-formatting
+  characters from the format string, as well as certain *constant*
+  error strings (e.g. `%(BADPREC)`).
+
+At this point **we make the following assumption**: there is no data
+from the printed *arguments* that is emitted to `pp.buf` directly by a
+`doPrint()` method. This is true of the implementation as of Go 1.14.
+
+From this point, this package contains a *custom patch* onto the
+default implementation: the calls to `p.printArg` performed by the
+`doPrint()` methods are redirected to a function callback that is
+injected by the `redact` package.
+
+Refreshing the sources
+======================
+
+The files in this directory have been imported from
+
+`$GOROOT/src/fmt/{format,print}.go`
+
+and
+
+`$GOROOT/src/internal/fmtsort`
+
+And patched using the included `.diff` files.
+
+To upgrade to a newer Go implementation, import the files anew and
+re-apply the patches.
+
+See the script `refresh.sh` for details.

vendor/github.com/cockroachdb/redact/internal/fmtsort/sort.go

@@ -0,0 +1,222 @@
+// Code generated from the Go standard library. DO NOT EDIT
+// GENERATED FILE DO NOT EDIT
+// Copyright 2018 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 fmtsort provides a general stable ordering mechanism
+// for maps, on behalf of the fmt and text/template packages.
+// It is not guaranteed to be efficient and works only for types
+// that are valid map keys.
+package fmtsort
+
+import (
+	"reflect"
+	"sort"
+)
+
+// Note: Throughout this package we avoid calling reflect.Value.Interface as
+// it is not always legal to do so and it's easier to avoid the issue than to face it.
+
+// SortedMap represents a map's keys and values. The keys and values are
+// aligned in index order: Value[i] is the value in the map corresponding to Key[i].
+type SortedMap struct {
+	Key   []reflect.Value
+	Value []reflect.Value
+}
+
+func (o *SortedMap) Len() int           { return len(o.Key) }
+func (o *SortedMap) Less(i, j int) bool { return compare(o.Key[i], o.Key[j]) < 0 }
+func (o *SortedMap) Swap(i, j int) {
+	o.Key[i], o.Key[j] = o.Key[j], o.Key[i]
+	o.Value[i], o.Value[j] = o.Value[j], o.Value[i]
+}
+
+// Sort accepts a map and returns a SortedMap that has the same keys and
+// values but in a stable sorted order according to the keys, modulo issues
+// raised by unorderable key values such as NaNs.
+//
+// The ordering rules are more general than with Go's < operator:
+//
+//  - when applicable, nil compares low
+//  - ints, floats, and strings order by <
+//  - NaN compares less than non-NaN floats
+//  - bool compares false before true
+//  - complex compares real, then imag
+//  - pointers compare by machine address
+//  - channel values compare by machine address
+//  - structs compare each field in turn
+//  - arrays compare each element in turn.
+//    Otherwise identical arrays compare by length.
+//  - interface values compare first by reflect.Type describing the concrete type
+//    and then by concrete value as described in the previous rules.
+//
+func Sort(mapValue reflect.Value) *SortedMap {
+	if mapValue.Type().Kind() != reflect.Map {
+		return nil
+	}
+	// Note: this code is arranged to not panic even in the presence
+	// of a concurrent map update. The runtime is responsible for
+	// yelling loudly if that happens. See issue 33275.
+	n := mapValue.Len()
+	key := make([]reflect.Value, 0, n)
+	value := make([]reflect.Value, 0, n)
+	iter := mapValue.MapRange()
+	for iter.Next() {
+		key = append(key, iter.Key())
+		value = append(value, iter.Value())
+	}
+	sorted := &SortedMap{
+		Key:   key,
+		Value: value,
+	}
+	sort.Stable(sorted)
+	return sorted
+}
+
+// compare compares two values of the same type. It returns -1, 0, 1
+// according to whether a > b (1), a == b (0), or a < b (-1).
+// If the types differ, it returns -1.
+// See the comment on Sort for the comparison rules.
+func compare(aVal, bVal reflect.Value) int {
+	aType, bType := aVal.Type(), bVal.Type()
+	if aType != bType {
+		return -1 // No good answer possible, but don't return 0: they're not equal.
+	}
+	switch aVal.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		a, b := aVal.Int(), bVal.Int()
+		switch {
+		case a < b:
+			return -1
+		case a > b:
+			return 1
+		default:
+			return 0
+		}
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		a, b := aVal.Uint(), bVal.Uint()
+		switch {
+		case a < b:
+			return -1
+		case a > b:
+			return 1
+		default:
+			return 0
+		}
+	case reflect.String:
+		a, b := aVal.String(), bVal.String()
+		switch {
+		case a < b:
+			return -1
+		case a > b:
+			return 1
+		default:
+			return 0
+		}
+	case reflect.Float32, reflect.Float64:
+		return floatCompare(aVal.Float(), bVal.Float())
+	case reflect.Complex64, reflect.Complex128:
+		a, b := aVal.Complex(), bVal.Complex()
+		if c := floatCompare(real(a), real(b)); c != 0 {
+			return c
+		}
+		return floatCompare(imag(a), imag(b))
+	case reflect.Bool:
+		a, b := aVal.Bool(), bVal.Bool()
+		switch {
+		case a == b:
+			return 0
+		case a:
+			return 1
+		default:
+			return -1
+		}
+	case reflect.Ptr:
+		a, b := aVal.Pointer(), bVal.Pointer()
+		switch {
+		case a < b:
+			return -1
+		case a > b:
+			return 1
+		default:
+			return 0
+		}
+	case reflect.Chan:
+		if c, ok := nilCompare(aVal, bVal); ok {
+			return c
+		}
+		ap, bp := aVal.Pointer(), bVal.Pointer()
+		switch {
+		case ap < bp:
+			return -1
+		case ap > bp:
+			return 1
+		default:
+			return 0
+		}
+	case reflect.Struct:
+		for i := 0; i < aVal.NumField(); i++ {
+			if c := compare(aVal.Field(i), bVal.Field(i)); c != 0 {
+				return c
+			}
+		}
+		return 0
+	case reflect.Array:
+		for i := 0; i < aVal.Len(); i++ {
+			if c := compare(aVal.Index(i), bVal.Index(i)); c != 0 {
+				return c
+			}
+		}
+		return 0
+	case reflect.Interface:
+		if c, ok := nilCompare(aVal, bVal); ok {
+			return c
+		}
+		c := compare(reflect.ValueOf(aVal.Elem().Type()), reflect.ValueOf(bVal.Elem().Type()))
+		if c != 0 {
+			return c
+		}
+		return compare(aVal.Elem(), bVal.Elem())
+	default:
+		// Certain types cannot appear as keys (maps, funcs, slices), but be explicit.
+		panic("bad type in compare: " + aType.String())
+	}
+}
+
+// nilCompare checks whether either value is nil. If not, the boolean is false.
+// If either value is nil, the boolean is true and the integer is the comparison
+// value. The comparison is defined to be 0 if both are nil, otherwise the one
+// nil value compares low. Both arguments must represent a chan, func,
+// interface, map, pointer, or slice.
+func nilCompare(aVal, bVal reflect.Value) (int, bool) {
+	if aVal.IsNil() {
+		if bVal.IsNil() {
+			return 0, true
+		}
+		return -1, true
+	}
+	if bVal.IsNil() {
+		return 1, true
+	}
+	return 0, false
+}
+
+// floatCompare compares two floating-point values. NaNs compare low.
+func floatCompare(a, b float64) int {
+	switch {
+	case isNaN(a):
+		return -1 // No good answer if b is a NaN so don't bother checking.
+	case isNaN(b):
+		return 1
+	case a < b:
+		return -1
+	case a > b:
+		return 1
+	}
+	return 0
+}
+
+func isNaN(a float64) bool {
+	return a != a
+}

vendor/github.com/cockroachdb/redact/internal/format.go

@@ -0,0 +1,595 @@
+// Code generated from the Go standard library. DO NOT EDIT
+// GENERATED FILE DO NOT EDIT
+// 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 (
+	"strconv"
+	"unicode/utf8"
+)
+
+const (
+	ldigits = "0123456789abcdefx"
+	udigits = "0123456789ABCDEFX"
+)
+
+const (
+	signed   = true
+	unsigned = false
+)
+
+// flags placed in a separate struct for easy clearing.
+type fmtFlags struct {
+	widPresent  bool
+	precPresent bool
+	minus       bool
+	plus        bool
+	sharp       bool
+	space       bool
+	zero        bool
+
+	// For the formats %+v %#v, we set the plusV/sharpV flags
+	// and clear the plus/sharp flags since %+v and %#v are in effect
+	// different, flagless formats set at the top level.
+	plusV  bool
+	sharpV bool
+}
+
+// A fmt is the raw formatter used by Printf etc.
+// It prints into a buffer that must be set up separately.
+type fmt struct {
+	buf *buffer
+
+	fmtFlags
+
+	wid  int // width
+	prec int // precision
+
+	// intbuf is large enough to store %b of an int64 with a sign and
+	// avoids padding at the end of the struct on 32 bit architectures.
+	intbuf [68]byte
+}
+
+func (f *fmt) clearflags() {
+	f.fmtFlags = fmtFlags{}
+}
+
+func (f *fmt) init(buf *buffer) {
+	f.buf = buf
+	f.clearflags()
+}
+
+// writePadding generates n bytes of padding.
+func (f *fmt) writePadding(n int) {
+	if n <= 0 { // No padding bytes needed.
+		return
+	}
+	buf := *f.buf
+	oldLen := len(buf)
+	newLen := oldLen + n
+	// Make enough room for padding.
+	if newLen > cap(buf) {
+		buf = make(buffer, cap(buf)*2+n)
+		copy(buf, *f.buf)
+	}
+	// Decide which byte the padding should be filled with.
+	padByte := byte(' ')
+	if f.zero {
+		padByte = byte('0')
+	}
+	// Fill padding with padByte.
+	padding := buf[oldLen:newLen]
+	for i := range padding {
+		padding[i] = padByte
+	}
+	*f.buf = buf[:newLen]
+}
+
+// pad appends b to f.buf, padded on left (!f.minus) or right (f.minus).
+func (f *fmt) pad(b []byte) {
+	if !f.widPresent || f.wid == 0 {
+		f.buf.write(b)
+		return
+	}
+	width := f.wid - utf8.RuneCount(b)
+	if !f.minus {
+		// left padding
+		f.writePadding(width)
+		f.buf.write(b)
+	} else {
+		// right padding
+		f.buf.write(b)
+		f.writePadding(width)
+	}
+}
+
+// padString appends s to f.buf, padded on left (!f.minus) or right (f.minus).
+func (f *fmt) padString(s string) {
+	if !f.widPresent || f.wid == 0 {
+		f.buf.writeString(s)
+		return
+	}
+	width := f.wid - utf8.RuneCountInString(s)
+	if !f.minus {
+		// left padding
+		f.writePadding(width)
+		f.buf.writeString(s)
+	} else {
+		// right padding
+		f.buf.writeString(s)
+		f.writePadding(width)
+	}
+}
+
+// fmtBoolean formats a boolean.
+func (f *fmt) fmtBoolean(v bool) {
+	if v {
+		f.padString("true")
+	} else {
+		f.padString("false")
+	}
+}
+
+// fmtUnicode formats a uint64 as "U+0078" or with f.sharp set as "U+0078 'x'".
+func (f *fmt) fmtUnicode(u uint64) {
+	buf := f.intbuf[0:]
+
+	// With default precision set the maximum needed buf length is 18
+	// for formatting -1 with %#U ("U+FFFFFFFFFFFFFFFF") which fits
+	// into the already allocated intbuf with a capacity of 68 bytes.
+	prec := 4
+	if f.precPresent && f.prec > 4 {
+		prec = f.prec
+		// Compute space needed for "U+" , number, " '", character, "'".
+		width := 2 + prec + 2 + utf8.UTFMax + 1
+		if width > len(buf) {
+			buf = make([]byte, width)
+		}
+	}
+
+	// Format into buf, ending at buf[i]. Formatting numbers is easier right-to-left.
+	i := len(buf)
+
+	// For %#U we want to add a space and a quoted character at the end of the buffer.
+	if f.sharp && u <= utf8.MaxRune && strconv.IsPrint(rune(u)) {
+		i--
+		buf[i] = '\''
+		i -= utf8.RuneLen(rune(u))
+		utf8.EncodeRune(buf[i:], rune(u))
+		i--
+		buf[i] = '\''
+		i--
+		buf[i] = ' '
+	}
+	// Format the Unicode code point u as a hexadecimal number.
+	for u >= 16 {
+		i--
+		buf[i] = udigits[u&0xF]
+		prec--
+		u >>= 4
+	}
+	i--
+	buf[i] = udigits[u]
+	prec--
+	// Add zeros in front of the number until requested precision is reached.
+	for prec > 0 {
+		i--
+		buf[i] = '0'
+		prec--
+	}
+	// Add a leading "U+".
+	i--
+	buf[i] = '+'
+	i--
+	buf[i] = 'U'
+
+	oldZero := f.zero
+	f.zero = false
+	f.pad(buf[i:])
+	f.zero = oldZero
+}
+
+// fmtInteger formats signed and unsigned integers.
+func (f *fmt) fmtInteger(u uint64, base int, isSigned bool, verb rune, digits string) {
+	negative := isSigned && int64(u) < 0
+	if negative {
+		u = -u
+	}
+
+	buf := f.intbuf[0:]
+	// The already allocated f.intbuf with a capacity of 68 bytes
+	// is large enough for integer formatting when no precision or width is set.
+	if f.widPresent || f.precPresent {
+		// Account 3 extra bytes for possible addition of a sign and "0x".
+		width := 3 + f.wid + f.prec // wid and prec are always positive.
+		if width > len(buf) {
+			// We're going to need a bigger boat.
+			buf = make([]byte, width)
+		}
+	}
+
+	// Two ways to ask for extra leading zero digits: %.3d or %03d.
+	// If both are specified the f.zero flag is ignored and
+	// padding with spaces is used instead.
+	prec := 0
+	if f.precPresent {
+		prec = f.prec
+		// Precision of 0 and value of 0 means "print nothing" but padding.
+		if prec == 0 && u == 0 {
+			oldZero := f.zero
+			f.zero = false
+			f.writePadding(f.wid)
+			f.zero = oldZero
+			return
+		}
+	} else if f.zero && f.widPresent {
+		prec = f.wid
+		if negative || f.plus || f.space {
+			prec-- // leave room for sign
+		}
+	}
+
+	// Because printing is easier right-to-left: format u into buf, ending at buf[i].
+	// We could make things marginally faster by splitting the 32-bit case out
+	// into a separate block but it's not worth the duplication, so u has 64 bits.
+	i := len(buf)
+	// Use constants for the division and modulo for more efficient code.
+	// Switch cases ordered by popularity.
+	switch base {
+	case 10:
+		for u >= 10 {
+			i--
+			next := u / 10
+			buf[i] = byte('0' + u - next*10)
+			u = next
+		}
+	case 16:
+		for u >= 16 {
+			i--
+			buf[i] = digits[u&0xF]
+			u >>= 4
+		}
+	case 8:
+		for u >= 8 {
+			i--
+			buf[i] = byte('0' + u&7)
+			u >>= 3
+		}
+	case 2:
+		for u >= 2 {
+			i--
+			buf[i] = byte('0' + u&1)
+			u >>= 1
+		}
+	default:
+		panic("fmt: unknown base; can't happen")
+	}
+	i--
+	buf[i] = digits[u]
+	for i > 0 && prec > len(buf)-i {
+		i--
+		buf[i] = '0'
+	}
+
+	// Various prefixes: 0x, -, etc.
+	if f.sharp {
+		switch base {
+		case 2:
+			// Add a leading 0b.
+			i--
+			buf[i] = 'b'
+			i--
+			buf[i] = '0'
+		case 8:
+			if buf[i] != '0' {
+				i--
+				buf[i] = '0'
+			}
+		case 16:
+			// Add a leading 0x or 0X.
+			i--
+			buf[i] = digits[16]
+			i--
+			buf[i] = '0'
+		}
+	}
+	if verb == 'O' {
+		i--
+		buf[i] = 'o'
+		i--
+		buf[i] = '0'
+	}
+
+	if negative {
+		i--
+		buf[i] = '-'
+	} else if f.plus {
+		i--
+		buf[i] = '+'
+	} else if f.space {
+		i--
+		buf[i] = ' '
+	}
+
+	// Left padding with zeros has already been handled like precision earlier
+	// or the f.zero flag is ignored due to an explicitly set precision.
+	oldZero := f.zero
+	f.zero = false
+	f.pad(buf[i:])
+	f.zero = oldZero
+}
+
+// truncate truncates the string s to the specified precision, if present.
+func (f *fmt) truncateString(s string) string {
+	if f.precPresent {
+		n := f.prec
+		for i := range s {
+			n--
+			if n < 0 {
+				return s[:i]
+			}
+		}
+	}
+	return s
+}
+
+// truncate truncates the byte slice b as a string of the specified precision, if present.
+func (f *fmt) truncate(b []byte) []byte {
+	if f.precPresent {
+		n := f.prec
+		for i := 0; i < len(b); {
+			n--
+			if n < 0 {
+				return b[:i]
+			}
+			wid := 1
+			if b[i] >= utf8.RuneSelf {
+				_, wid = utf8.DecodeRune(b[i:])
+			}
+			i += wid
+		}
+	}
+	return b
+}
+
+// fmtS formats a string.
+func (f *fmt) fmtS(s string) {
+	s = f.truncateString(s)
+	f.padString(s)
+}
+
+// fmtBs formats the byte slice b as if it was formatted as string with fmtS.
+func (f *fmt) fmtBs(b []byte) {
+	b = f.truncate(b)
+	f.pad(b)
+}
+
+// fmtSbx formats a string or byte slice as a hexadecimal encoding of its bytes.
+func (f *fmt) fmtSbx(s string, b []byte, digits string) {
+	length := len(b)
+	if b == nil {
+		// No byte slice present. Assume string s should be encoded.
+		length = len(s)
+	}
+	// Set length to not process more bytes than the precision demands.
+	if f.precPresent && f.prec < length {
+		length = f.prec
+	}
+	// Compute width of the encoding taking into account the f.sharp and f.space flag.
+	width := 2 * length
+	if width > 0 {
+		if f.space {
+			// Each element encoded by two hexadecimals will get a leading 0x or 0X.
+			if f.sharp {
+				width *= 2
+			}
+			// Elements will be separated by a space.
+			width += length - 1
+		} else if f.sharp {
+			// Only a leading 0x or 0X will be added for the whole string.
+			width += 2
+		}
+	} else { // The byte slice or string that should be encoded is empty.
+		if f.widPresent {
+			f.writePadding(f.wid)
+		}
+		return
+	}
+	// Handle padding to the left.
+	if f.widPresent && f.wid > width && !f.minus {
+		f.writePadding(f.wid - width)
+	}
+	// Write the encoding directly into the output buffer.
+	buf := *f.buf
+	if f.sharp {
+		// Add leading 0x or 0X.
+		buf = append(buf, '0', digits[16])
+	}
+	var c byte
+	for i := 0; i < length; i++ {
+		if f.space && i > 0 {
+			// Separate elements with a space.
+			buf = append(buf, ' ')
+			if f.sharp {
+				// Add leading 0x or 0X for each element.
+				buf = append(buf, '0', digits[16])
+			}
+		}
+		if b != nil {
+			c = b[i] // Take a byte from the input byte slice.
+		} else {
+			c = s[i] // Take a byte from the input string.
+		}
+		// Encode each byte as two hexadecimal digits.
+		buf = append(buf, digits[c>>4], digits[c&0xF])
+	}
+	*f.buf = buf
+	// Handle padding to the right.
+	if f.widPresent && f.wid > width && f.minus {
+		f.writePadding(f.wid - width)
+	}
+}
+
+// fmtSx formats a string as a hexadecimal encoding of its bytes.
+func (f *fmt) fmtSx(s, digits string) {
+	f.fmtSbx(s, nil, digits)
+}
+
+// fmtBx formats a byte slice as a hexadecimal encoding of its bytes.
+func (f *fmt) fmtBx(b []byte, digits string) {
+	f.fmtSbx("", b, digits)
+}
+
+// fmtQ formats a string as a double-quoted, escaped Go string constant.
+// If f.sharp is set a raw (backquoted) string may be returned instead
+// if the string does not contain any control characters other than tab.
+func (f *fmt) fmtQ(s string) {
+	s = f.truncateString(s)
+	if f.sharp && strconv.CanBackquote(s) {
+		f.padString("`" + s + "`")
+		return
+	}
+	buf := f.intbuf[:0]
+	if f.plus {
+		f.pad(strconv.AppendQuoteToASCII(buf, s))
+	} else {
+		f.pad(strconv.AppendQuote(buf, s))
+	}
+}
+
+// fmtC formats an integer as a Unicode character.
+// If the character is not valid Unicode, it will print '\ufffd'.
+func (f *fmt) fmtC(c uint64) {
+	r := rune(c)
+	if c > utf8.MaxRune {
+		r = utf8.RuneError
+	}
+	buf := f.intbuf[:0]
+	w := utf8.EncodeRune(buf[:utf8.UTFMax], r)
+	f.pad(buf[:w])
+}
+
+// fmtQc formats an integer as a single-quoted, escaped Go character constant.
+// If the character is not valid Unicode, it will print '\ufffd'.
+func (f *fmt) fmtQc(c uint64) {
+	r := rune(c)
+	if c > utf8.MaxRune {
+		r = utf8.RuneError
+	}
+	buf := f.intbuf[:0]
+	if f.plus {
+		f.pad(strconv.AppendQuoteRuneToASCII(buf, r))
+	} else {
+		f.pad(strconv.AppendQuoteRune(buf, r))
+	}
+}
+
+// fmtFloat formats a float64. It assumes that verb is a valid format specifier
+// for strconv.AppendFloat and therefore fits into a byte.
+func (f *fmt) fmtFloat(v float64, size int, verb rune, prec int) {
+	// Explicit precision in format specifier overrules default precision.
+	if f.precPresent {
+		prec = f.prec
+	}
+	// Format number, reserving space for leading + sign if needed.
+	num := strconv.AppendFloat(f.intbuf[:1], v, byte(verb), prec, size)
+	if num[1] == '-' || num[1] == '+' {
+		num = num[1:]
+	} else {
+		num[0] = '+'
+	}
+	// f.space means to add a leading space instead of a "+" sign unless
+	// the sign is explicitly asked for by f.plus.
+	if f.space && num[0] == '+' && !f.plus {
+		num[0] = ' '
+	}
+	// Special handling for infinities and NaN,
+	// which don't look like a number so shouldn't be padded with zeros.
+	if num[1] == 'I' || num[1] == 'N' {
+		oldZero := f.zero
+		f.zero = false
+		// Remove sign before NaN if not asked for.
+		if num[1] == 'N' && !f.space && !f.plus {
+			num = num[1:]
+		}
+		f.pad(num)
+		f.zero = oldZero
+		return
+	}
+	// The sharp flag forces printing a decimal point for non-binary formats
+	// and retains trailing zeros, which we may need to restore.
+	if f.sharp && verb != 'b' {
+		digits := 0
+		switch verb {
+		case 'v', 'g', 'G', 'x':
+			digits = prec
+			// If no precision is set explicitly use a precision of 6.
+			if digits == -1 {
+				digits = 6
+			}
+		}
+
+		// Buffer pre-allocated with enough room for
+		// exponent notations of the form "e+123" or "p-1023".
+		var tailBuf [6]byte
+		tail := tailBuf[:0]
+
+		hasDecimalPoint := false
+		sawNonzeroDigit := false
+		// Starting from i = 1 to skip sign at num[0].
+		for i := 1; i < len(num); i++ {
+			switch num[i] {
+			case '.':
+				hasDecimalPoint = true
+			case 'p', 'P':
+				tail = append(tail, num[i:]...)
+				num = num[:i]
+			case 'e', 'E':
+				if verb != 'x' && verb != 'X' {
+					tail = append(tail, num[i:]...)
+					num = num[:i]
+					break
+				}
+				fallthrough
+			default:
+				if num[i] != '0' {
+					sawNonzeroDigit = true
+				}
+				// Count significant digits after the first non-zero digit.
+				if sawNonzeroDigit {
+					digits--
+				}
+			}
+		}
+		if !hasDecimalPoint {
+			// Leading digit 0 should contribute once to digits.
+			if len(num) == 2 && num[1] == '0' {
+				digits--
+			}
+			num = append(num, '.')
+		}
+		for digits > 0 {
+			num = append(num, '0')
+			digits--
+		}
+		num = append(num, tail...)
+	}
+	// We want a sign if asked for and if the sign is not positive.
+	if f.plus || num[0] != '+' {
+		// If we're zero padding to the left we want the sign before the leading zeros.
+		// Achieve this by writing the sign out and then padding the unsigned number.
+		if f.zero && f.widPresent && f.wid > len(num) {
+			f.buf.writeByte(num[0])
+			f.writePadding(f.wid - len(num))
+			f.buf.write(num[1:])
+			return
+		}
+		f.pad(num)
+		return
+	}
+	// No sign to show and the number is positive; just print the unsigned number.
+	f.pad(num[1:])
+}

vendor/github.com/cockroachdb/redact/internal/hooks.go

@@ -0,0 +1,83 @@
+// Copyright 2020 The Cockroach Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+// implied. See the License for the specific language governing
+// permissions and limitations under the License.
+
+package fmt
+
+// printArg overrides the original implementation by redirecting the
+// call to a substitute function in the printer, if available.
+func (p *pp) printArg(a interface{}, verb rune) {
+	if p.printArgSubstituteFn != nil {
+		p.substituteState = p.printArgSubstituteFn(p, a, verb)
+	} else {
+		p.printArgOrig(a, verb)
+	}
+}
+
+// InternalPrinter exposes pp to the redact package.
+type InternalPrinter = pp
+
+// InternalBuffer exposes buffer to the redact package.
+type InternalBuffer = buffer
+
+// NewInternalPrinter exposes pp allocation to the redact package.
+func NewInternalPrinter() *InternalPrinter { return newPrinter() }
+
+// SetHook connects an outer printer to the inner printer.
+func SetHook(
+	p *InternalPrinter, fn func(p *InternalPrinter, arg interface{}, verb rune) (newState int),
+) {
+	p.printArgSubstituteFn = fn
+}
+
+// Free exposes pp deallocation to the redact package.
+func Free(p *InternalPrinter) {
+	p.substituteState = 0
+	p.printArgSubstituteFn = nil
+	p.free()
+}
+
+// Buf exposes the string buffer to the redact package.
+func Buf(p *InternalPrinter) []byte { return []byte(p.buf) }
+
+// GetState exposes the state to the redact package.
+func GetState(p *InternalPrinter) int {
+	return p.substituteState
+}
+
+// SetState exposes the string buffer to the redact package.
+func SetState(p *InternalPrinter, b []byte) {
+	p.buf = buffer(b)
+	p.substituteState = len(p.buf)
+}
+
+// Append adds bytes to the buffer.
+func Append(p *InternalPrinter, b []byte) { p.buf.write(b) }
+
+// PrintArg exposes the printArgOrig() method to the redact package.
+func PrintArg(p *InternalPrinter, a interface{}, verb rune) { p.printArgOrig(a, verb) }
+
+// DoPrint exposes the doPrint() method to the redact package.
+func DoPrint(p *InternalPrinter, a []interface{}) { p.doPrint(a) }
+
+// DoPrintf exposes the doPrintf() method to the redact package.
+func DoPrintf(p *InternalPrinter, format string, a []interface{}) { p.doPrintf(format, a) }
+
+// SetCollectError enables wrapped error collection.
+func SetCollectError(p *InternalPrinter) { p.wrapErrs = true }
+
+// CollectingError exposes wrapped error collection.
+func CollectingError(p *InternalPrinter) bool { return p.wrapErrs }
+
+// WrappedError retrieves the wrapped error if found.
+func WrappedError(p *InternalPrinter) error { return p.wrappedErr }

vendor/github.com/cockroachdb/redact/internal/print.go.diff

@@ -0,0 +1,58 @@
+--- print.go.orig	2020-08-26 14:49:30.396184000 +0200
++++ print.go	2020-08-26 14:50:29.330829000 +0200
+@@ -1,3 +1,6 @@
++// Code generated from print.go.orig. DO NOT EDIT
++// GENERATED FILE DO NOT EDIT
++//
+ // 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.
+@@ -5,12 +8,16 @@
+ package fmt
+ 
+ import (
+-	"internal/fmtsort"
++	// CUSTOM: needed to avoid a type mismatch on Formatter.
++	origFmt "fmt"
+ 	"io"
+ 	"os"
+ 	"reflect"
+ 	"sync"
+ 	"unicode/utf8"
++
++	// CUSTOM: our own import since we can't use internal from go stdlib.
++	"github.com/cockroachdb/redact/internal/fmtsort"
+ )
+ 
+ // Strings for use with buffer.WriteString.
+@@ -51,7 +58,8 @@
+ // The implementation of Format may call Sprint(f) or Fprint(f) etc.
+ // to generate its output.
+ type Formatter interface {
+-	Format(f State, c rune)
++	// CUSTOM: refer to the original type, not the one defined here.
++	Format(f origFmt.State, c rune)
+ }
+ 
+ // Stringer is implemented by any value that has a String method,
+@@ -105,6 +113,10 @@
+ type pp struct {
+ 	buf buffer
+ 
++	// CUSTOM: hook fn for the redact package.
++	printArgSubstituteFn func(p *pp, a interface{}, verb rune) (newState int)
++	substituteState      int
++
+ 	// arg holds the current item, as an interface{}.
+ 	arg interface{}
+ 
+@@ -635,7 +647,8 @@
+ 	return false
+ }
+ 
+-func (p *pp) printArg(arg interface{}, verb rune) {
++// CUSTOM: printArg() renamed to printArgOrig().
++func (p *pp) printArgOrig(arg interface{}, verb rune) {
+ 	p.arg = arg
+ 	p.value = reflect.Value{}
+ 

vendor/github.com/cockroachdb/redact/internal/refresh.sh

@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+#
+# This file re-generates the sources in this directory from the Go
+# standard library.
+#
+set -euxo pipefail
+
+(
+    echo "// Code generated from the Go standard library. DO NOT EDIT"
+    echo "// GENERATED FILE DO NOT EDIT"
+    cat $GOROOT/src/fmt/format.go
+) >format.go
+
+cp $GOROOT/src/fmt/print.go print.go
+patch -p0 <print.go.diff
+
+mkdir -p fmtsort
+for a in $GOROOT/src/internal/fmtsort/*; do
+    if expr "$a" : ".*_test.go"; then
+	continue
+    fi
+    n=$(basename "$a")
+    (
+	echo "// Code generated from the Go standard library. DO NOT EDIT"
+	echo "// GENERATED FILE DO NOT EDIT"
+	cat "$a"
+    ) >fmtsort/"$n"
+done
+