fork mysql driverHEADmaster

1 files changed, 874 insertions, 0 deletions

diff --git a/utils.go b/utils.go
new file mode 100644
index 0000000..fbbf49d
--- /dev/null
+++ b/utils.go
@@ -0,0 +1,874 @@
+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2012 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mariadb
+
+import (
+	"crypto/tls"
+	"database/sql"
+	"database/sql/driver"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"io"
+	"strconv"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+// Registry for custom tls.Configs
+var (
+	tlsConfigLock     sync.RWMutex
+	tlsConfigRegistry map[string]*tls.Config
+)
+
+// RegisterTLSConfig registers a custom tls.Config to be used with sql.Open.
+// Use the key as a value in the DSN where tls=value.
+//
+// Note: The provided tls.Config is exclusively owned by the driver after
+// registering it.
+//
+//  rootCertPool := x509.NewCertPool()
+//  pem, err := ioutil.ReadFile("/path/ca-cert.pem")
+//  if err != nil {
+//      log.Fatal(err)
+//  }
+//  if ok := rootCertPool.AppendCertsFromPEM(pem); !ok {
+//      log.Fatal("Failed to append PEM.")
+//  }
+//  clientCert := make([]tls.Certificate, 0, 1)
+//  certs, err := tls.LoadX509KeyPair("/path/client-cert.pem", "/path/client-key.pem")
+//  if err != nil {
+//      log.Fatal(err)
+//  }
+//  clientCert = append(clientCert, certs)
+//  mysql.RegisterTLSConfig("custom", &tls.Config{
+//      RootCAs: rootCertPool,
+//      Certificates: clientCert,
+//  })
+//  db, err := sql.Open("mysql", "user@tcp(localhost:3306)/test?tls=custom")
+//
+func RegisterTLSConfig(key string, config *tls.Config) error {
+	if _, isBool := readBool(key); isBool || strings.ToLower(key) == "skip-verify" || strings.ToLower(key) == "preferred" {
+		return fmt.Errorf("key '%s' is reserved", key)
+	}
+
+	tlsConfigLock.Lock()
+	if tlsConfigRegistry == nil {
+		tlsConfigRegistry = make(map[string]*tls.Config)
+	}
+
+	tlsConfigRegistry[key] = config
+	tlsConfigLock.Unlock()
+	return nil
+}
+
+// DeregisterTLSConfig removes the tls.Config associated with key.
+func DeregisterTLSConfig(key string) {
+	tlsConfigLock.Lock()
+	if tlsConfigRegistry != nil {
+		delete(tlsConfigRegistry, key)
+	}
+	tlsConfigLock.Unlock()
+}
+
+func getTLSConfigClone(key string) (config *tls.Config) {
+	tlsConfigLock.RLock()
+	if v, ok := tlsConfigRegistry[key]; ok {
+		config = v.Clone()
+	}
+	tlsConfigLock.RUnlock()
+	return
+}
+
+// Returns the bool value of the input.
+// The 2nd return value indicates if the input was a valid bool value
+func readBool(input string) (value bool, valid bool) {
+	switch input {
+	case "1", "true", "TRUE", "True":
+		return true, true
+	case "0", "false", "FALSE", "False":
+		return false, true
+	}
+
+	// Not a valid bool value
+	return
+}
+
+/******************************************************************************
+*                           Time related utils                                *
+******************************************************************************/
+
+func parseDateTime(b []byte, loc *time.Location) (time.Time, error) {
+	const base = "0000-00-00 00:00:00.000000"
+	switch len(b) {
+	case 10, 19, 21, 22, 23, 24, 25, 26: // up to "YYYY-MM-DD HH:MM:SS.MMMMMM"
+		if string(b) == base[:len(b)] {
+			return time.Time{}, nil
+		}
+
+		year, err := parseByteYear(b)
+		if err != nil {
+			return time.Time{}, err
+		}
+		if year <= 0 {
+			year = 1
+		}
+
+		if b[4] != '-' {
+			return time.Time{}, fmt.Errorf("bad value for field: `%c`", b[4])
+		}
+
+		m, err := parseByte2Digits(b[5], b[6])
+		if err != nil {
+			return time.Time{}, err
+		}
+		if m <= 0 {
+			m = 1
+		}
+		month := time.Month(m)
+
+		if b[7] != '-' {
+			return time.Time{}, fmt.Errorf("bad value for field: `%c`", b[7])
+		}
+
+		day, err := parseByte2Digits(b[8], b[9])
+		if err != nil {
+			return time.Time{}, err
+		}
+		if day <= 0 {
+			day = 1
+		}
+		if len(b) == 10 {
+			return time.Date(year, month, day, 0, 0, 0, 0, loc), nil
+		}
+
+		if b[10] != ' ' {
+			return time.Time{}, fmt.Errorf("bad value for field: `%c`", b[10])
+		}
+
+		hour, err := parseByte2Digits(b[11], b[12])
+		if err != nil {
+			return time.Time{}, err
+		}
+		if b[13] != ':' {
+			return time.Time{}, fmt.Errorf("bad value for field: `%c`", b[13])
+		}
+
+		min, err := parseByte2Digits(b[14], b[15])
+		if err != nil {
+			return time.Time{}, err
+		}
+		if b[16] != ':' {
+			return time.Time{}, fmt.Errorf("bad value for field: `%c`", b[16])
+		}
+
+		sec, err := parseByte2Digits(b[17], b[18])
+		if err != nil {
+			return time.Time{}, err
+		}
+		if len(b) == 19 {
+			return time.Date(year, month, day, hour, min, sec, 0, loc), nil
+		}
+
+		if b[19] != '.' {
+			return time.Time{}, fmt.Errorf("bad value for field: `%c`", b[19])
+		}
+		nsec, err := parseByteNanoSec(b[20:])
+		if err != nil {
+			return time.Time{}, err
+		}
+		return time.Date(year, month, day, hour, min, sec, nsec, loc), nil
+	default:
+		return time.Time{}, fmt.Errorf("invalid time bytes: %s", b)
+	}
+}
+
+func parseByteYear(b []byte) (int, error) {
+	year, n := 0, 1000
+	for i := 0; i < 4; i++ {
+		v, err := bToi(b[i])
+		if err != nil {
+			return 0, err
+		}
+		year += v * n
+		n /= 10
+	}
+	return year, nil
+}
+
+func parseByte2Digits(b1, b2 byte) (int, error) {
+	d1, err := bToi(b1)
+	if err != nil {
+		return 0, err
+	}
+	d2, err := bToi(b2)
+	if err != nil {
+		return 0, err
+	}
+	return d1*10 + d2, nil
+}
+
+func parseByteNanoSec(b []byte) (int, error) {
+	ns, digit := 0, 100000 // max is 6-digits
+	for i := 0; i < len(b); i++ {
+		v, err := bToi(b[i])
+		if err != nil {
+			return 0, err
+		}
+		ns += v * digit
+		digit /= 10
+	}
+	// nanoseconds has 10-digits. (needs to scale digits)
+	// 10 - 6 = 4, so we have to multiple 1000.
+	return ns * 1000, nil
+}
+
+func bToi(b byte) (int, error) {
+	if b < '0' || b > '9' {
+		return 0, errors.New("not [0-9]")
+	}
+	return int(b - '0'), nil
+}
+
+func parseBinaryDateTime(num uint64, data []byte, loc *time.Location) (driver.Value, error) {
+	switch num {
+	case 0:
+		return time.Time{}, nil
+	case 4:
+		return time.Date(
+			int(binary.LittleEndian.Uint16(data[:2])), // year
+			time.Month(data[2]),                       // month
+			int(data[3]),                              // day
+			0, 0, 0, 0,
+			loc,
+		), nil
+	case 7:
+		return time.Date(
+			int(binary.LittleEndian.Uint16(data[:2])), // year
+			time.Month(data[2]),                       // month
+			int(data[3]),                              // day
+			int(data[4]),                              // hour
+			int(data[5]),                              // minutes
+			int(data[6]),                              // seconds
+			0,
+			loc,
+		), nil
+	case 11:
+		return time.Date(
+			int(binary.LittleEndian.Uint16(data[:2])), // year
+			time.Month(data[2]),                       // month
+			int(data[3]),                              // day
+			int(data[4]),                              // hour
+			int(data[5]),                              // minutes
+			int(data[6]),                              // seconds
+			int(binary.LittleEndian.Uint32(data[7:11]))*1000, // nanoseconds
+			loc,
+		), nil
+	}
+	return nil, fmt.Errorf("invalid DATETIME packet length %d", num)
+}
+
+func appendDateTime(buf []byte, t time.Time) ([]byte, error) {
+	year, month, day := t.Date()
+	hour, min, sec := t.Clock()
+	nsec := t.Nanosecond()
+
+	if year < 1 || year > 9999 {
+		return buf, errors.New("year is not in the range [1, 9999]: " + strconv.Itoa(year)) // use errors.New instead of fmt.Errorf to avoid year escape to heap
+	}
+	year100 := year / 100
+	year1 := year % 100
+
+	var localBuf [len("2006-01-02T15:04:05.999999999")]byte // does not escape
+	localBuf[0], localBuf[1], localBuf[2], localBuf[3] = digits10[year100], digits01[year100], digits10[year1], digits01[year1]
+	localBuf[4] = '-'
+	localBuf[5], localBuf[6] = digits10[month], digits01[month]
+	localBuf[7] = '-'
+	localBuf[8], localBuf[9] = digits10[day], digits01[day]
+
+	if hour == 0 && min == 0 && sec == 0 && nsec == 0 {
+		return append(buf, localBuf[:10]...), nil
+	}
+
+	localBuf[10] = ' '
+	localBuf[11], localBuf[12] = digits10[hour], digits01[hour]
+	localBuf[13] = ':'
+	localBuf[14], localBuf[15] = digits10[min], digits01[min]
+	localBuf[16] = ':'
+	localBuf[17], localBuf[18] = digits10[sec], digits01[sec]
+
+	if nsec == 0 {
+		return append(buf, localBuf[:19]...), nil
+	}
+	nsec100000000 := nsec / 100000000
+	nsec1000000 := (nsec / 1000000) % 100
+	nsec10000 := (nsec / 10000) % 100
+	nsec100 := (nsec / 100) % 100
+	nsec1 := nsec % 100
+	localBuf[19] = '.'
+
+	// milli second
+	localBuf[20], localBuf[21], localBuf[22] =
+		digits01[nsec100000000], digits10[nsec1000000], digits01[nsec1000000]
+	// micro second
+	localBuf[23], localBuf[24], localBuf[25] =
+		digits10[nsec10000], digits01[nsec10000], digits10[nsec100]
+	// nano second
+	localBuf[26], localBuf[27], localBuf[28] =
+		digits01[nsec100], digits10[nsec1], digits01[nsec1]
+
+	// trim trailing zeros
+	n := len(localBuf)
+	for n > 0 && localBuf[n-1] == '0' {
+		n--
+	}
+
+	return append(buf, localBuf[:n]...), nil
+}
+
+// zeroDateTime is used in formatBinaryDateTime to avoid an allocation
+// if the DATE or DATETIME has the zero value.
+// It must never be changed.
+// The current behavior depends on database/sql copying the result.
+var zeroDateTime = []byte("0000-00-00 00:00:00.000000")
+
+const digits01 = "0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789"
+const digits10 = "0000000000111111111122222222223333333333444444444455555555556666666666777777777788888888889999999999"
+
+func appendMicrosecs(dst, src []byte, decimals int) []byte {
+	if decimals <= 0 {
+		return dst
+	}
+	if len(src) == 0 {
+		return append(dst, ".000000"[:decimals+1]...)
+	}
+
+	microsecs := binary.LittleEndian.Uint32(src[:4])
+	p1 := byte(microsecs / 10000)
+	microsecs -= 10000 * uint32(p1)
+	p2 := byte(microsecs / 100)
+	microsecs -= 100 * uint32(p2)
+	p3 := byte(microsecs)
+
+	switch decimals {
+	default:
+		return append(dst, '.',
+			digits10[p1], digits01[p1],
+			digits10[p2], digits01[p2],
+			digits10[p3], digits01[p3],
+		)
+	case 1:
+		return append(dst, '.',
+			digits10[p1],
+		)
+	case 2:
+		return append(dst, '.',
+			digits10[p1], digits01[p1],
+		)
+	case 3:
+		return append(dst, '.',
+			digits10[p1], digits01[p1],
+			digits10[p2],
+		)
+	case 4:
+		return append(dst, '.',
+			digits10[p1], digits01[p1],
+			digits10[p2], digits01[p2],
+		)
+	case 5:
+		return append(dst, '.',
+			digits10[p1], digits01[p1],
+			digits10[p2], digits01[p2],
+			digits10[p3],
+		)
+	}
+}
+
+func formatBinaryDateTime(src []byte, length uint8) (driver.Value, error) {
+	// length expects the deterministic length of the zero value,
+	// negative time and 100+ hours are automatically added if needed
+	if len(src) == 0 {
+		return zeroDateTime[:length], nil
+	}
+	var dst []byte      // return value
+	var p1, p2, p3 byte // current digit pair
+
+	switch length {
+	case 10, 19, 21, 22, 23, 24, 25, 26:
+	default:
+		t := "DATE"
+		if length > 10 {
+			t += "TIME"
+		}
+		return nil, fmt.Errorf("illegal %s length %d", t, length)
+	}
+	switch len(src) {
+	case 4, 7, 11:
+	default:
+		t := "DATE"
+		if length > 10 {
+			t += "TIME"
+		}
+		return nil, fmt.Errorf("illegal %s packet length %d", t, len(src))
+	}
+	dst = make([]byte, 0, length)
+	// start with the date
+	year := binary.LittleEndian.Uint16(src[:2])
+	pt := year / 100
+	p1 = byte(year - 100*uint16(pt))
+	p2, p3 = src[2], src[3]
+	dst = append(dst,
+		digits10[pt], digits01[pt],
+		digits10[p1], digits01[p1], '-',
+		digits10[p2], digits01[p2], '-',
+		digits10[p3], digits01[p3],
+	)
+	if length == 10 {
+		return dst, nil
+	}
+	if len(src) == 4 {
+		return append(dst, zeroDateTime[10:length]...), nil
+	}
+	dst = append(dst, ' ')
+	p1 = src[4] // hour
+	src = src[5:]
+
+	// p1 is 2-digit hour, src is after hour
+	p2, p3 = src[0], src[1]
+	dst = append(dst,
+		digits10[p1], digits01[p1], ':',
+		digits10[p2], digits01[p2], ':',
+		digits10[p3], digits01[p3],
+	)
+	return appendMicrosecs(dst, src[2:], int(length)-20), nil
+}
+
+func formatBinaryTime(src []byte, length uint8) (driver.Value, error) {
+	// length expects the deterministic length of the zero value,
+	// negative time and 100+ hours are automatically added if needed
+	if len(src) == 0 {
+		return zeroDateTime[11 : 11+length], nil
+	}
+	var dst []byte // return value
+
+	switch length {
+	case
+		8,                      // time (can be up to 10 when negative and 100+ hours)
+		10, 11, 12, 13, 14, 15: // time with fractional seconds
+	default:
+		return nil, fmt.Errorf("illegal TIME length %d", length)
+	}
+	switch len(src) {
+	case 8, 12:
+	default:
+		return nil, fmt.Errorf("invalid TIME packet length %d", len(src))
+	}
+	// +2 to enable negative time and 100+ hours
+	dst = make([]byte, 0, length+2)
+	if src[0] == 1 {
+		dst = append(dst, '-')
+	}
+	days := binary.LittleEndian.Uint32(src[1:5])
+	hours := int64(days)*24 + int64(src[5])
+
+	if hours >= 100 {
+		dst = strconv.AppendInt(dst, hours, 10)
+	} else {
+		dst = append(dst, digits10[hours], digits01[hours])
+	}
+
+	min, sec := src[6], src[7]
+	dst = append(dst, ':',
+		digits10[min], digits01[min], ':',
+		digits10[sec], digits01[sec],
+	)
+	return appendMicrosecs(dst, src[8:], int(length)-9), nil
+}
+
+/******************************************************************************
+*                       Convert from and to bytes                             *
+******************************************************************************/
+
+func uint64ToBytes(n uint64) []byte {
+	return []byte{
+		byte(n),
+		byte(n >> 8),
+		byte(n >> 16),
+		byte(n >> 24),
+		byte(n >> 32),
+		byte(n >> 40),
+		byte(n >> 48),
+		byte(n >> 56),
+	}
+}
+
+func uint64ToString(n uint64) []byte {
+	var a [20]byte
+	i := 20
+
+	// U+0030 = 0
+	// ...
+	// U+0039 = 9
+
+	var q uint64
+	for n >= 10 {
+		i--
+		q = n / 10
+		a[i] = uint8(n-q*10) + 0x30
+		n = q
+	}
+
+	i--
+	a[i] = uint8(n) + 0x30
+
+	return a[i:]
+}
+
+// treats string value as unsigned integer representation
+func stringToInt(b []byte) int {
+	val := 0
+	for i := range b {
+		val *= 10
+		val += int(b[i] - 0x30)
+	}
+	return val
+}
+
+// returns the string read as a bytes slice, whether the value is NULL,
+// the number of bytes read and an error, in case the string is longer than
+// the input slice
+func readLengthEncodedString(b []byte) ([]byte, bool, int, error) {
+	// Get length
+	num, isNull, n := readLengthEncodedInteger(b)
+	if num < 1 {
+		return b[n:n], isNull, n, nil
+	}
+
+	n += int(num)
+
+	// Check data length
+	if len(b) >= n {
+		return b[n-int(num) : n : n], false, n, nil
+	}
+	return nil, false, n, io.EOF
+}
+
+// returns the number of bytes skipped and an error, in case the string is
+// longer than the input slice
+func skipLengthEncodedString(b []byte) (int, error) {
+	// Get length
+	num, _, n := readLengthEncodedInteger(b)
+	if num < 1 {
+		return n, nil
+	}
+
+	n += int(num)
+
+	// Check data length
+	if len(b) >= n {
+		return n, nil
+	}
+	return n, io.EOF
+}
+
+// returns the number read, whether the value is NULL and the number of bytes read
+func readLengthEncodedInteger(b []byte) (uint64, bool, int) {
+	// See issue #349
+	if len(b) == 0 {
+		return 0, true, 1
+	}
+
+	switch b[0] {
+	// 251: NULL
+	case 0xfb:
+		return 0, true, 1
+
+	// 252: value of following 2
+	case 0xfc:
+		return uint64(b[1]) | uint64(b[2])<<8, false, 3
+
+	// 253: value of following 3
+	case 0xfd:
+		return uint64(b[1]) | uint64(b[2])<<8 | uint64(b[3])<<16, false, 4
+
+	// 254: value of following 8
+	case 0xfe:
+		return uint64(b[1]) | uint64(b[2])<<8 | uint64(b[3])<<16 |
+				uint64(b[4])<<24 | uint64(b[5])<<32 | uint64(b[6])<<40 |
+				uint64(b[7])<<48 | uint64(b[8])<<56,
+			false, 9
+	}
+
+	// 0-250: value of first byte
+	return uint64(b[0]), false, 1
+}
+
+// encodes a uint64 value and appends it to the given bytes slice
+func appendLengthEncodedInteger(b []byte, n uint64) []byte {
+	switch {
+	case n <= 250:
+		return append(b, byte(n))
+
+	case n <= 0xffff:
+		return append(b, 0xfc, byte(n), byte(n>>8))
+
+	case n <= 0xffffff:
+		return append(b, 0xfd, byte(n), byte(n>>8), byte(n>>16))
+	}
+	return append(b, 0xfe, byte(n), byte(n>>8), byte(n>>16), byte(n>>24),
+		byte(n>>32), byte(n>>40), byte(n>>48), byte(n>>56))
+}
+
+// reserveBuffer checks cap(buf) and expand buffer to len(buf) + appendSize.
+// If cap(buf) is not enough, reallocate new buffer.
+func reserveBuffer(buf []byte, appendSize int) []byte {
+	newSize := len(buf) + appendSize
+	if cap(buf) < newSize {
+		// Grow buffer exponentially
+		newBuf := make([]byte, len(buf)*2+appendSize)
+		copy(newBuf, buf)
+		buf = newBuf
+	}
+	return buf[:newSize]
+}
+
+// escapeBytesBackslash escapes []byte with backslashes (\)
+// This escapes the contents of a string (provided as []byte) by adding backslashes before special
+// characters, and turning others into specific escape sequences, such as
+// turning newlines into \n and null bytes into \0.
+// https://github.com/mysql/mysql-server/blob/mysql-5.7.5/mysys/charset.c#L823-L932
+func escapeBytesBackslash(buf, v []byte) []byte {
+	pos := len(buf)
+	buf = reserveBuffer(buf, len(v)*2)
+
+	for _, c := range v {
+		switch c {
+		case '\x00':
+			buf[pos+1] = '0'
+			buf[pos] = '\\'
+			pos += 2
+		case '\n':
+			buf[pos+1] = 'n'
+			buf[pos] = '\\'
+			pos += 2
+		case '\r':
+			buf[pos+1] = 'r'
+			buf[pos] = '\\'
+			pos += 2
+		case '\x1a':
+			buf[pos+1] = 'Z'
+			buf[pos] = '\\'
+			pos += 2
+		case '\'':
+			buf[pos+1] = '\''
+			buf[pos] = '\\'
+			pos += 2
+		case '"':
+			buf[pos+1] = '"'
+			buf[pos] = '\\'
+			pos += 2
+		case '\\':
+			buf[pos+1] = '\\'
+			buf[pos] = '\\'
+			pos += 2
+		default:
+			buf[pos] = c
+			pos++
+		}
+	}
+
+	return buf[:pos]
+}
+
+// escapeStringBackslash is similar to escapeBytesBackslash but for string.
+func escapeStringBackslash(buf []byte, v string) []byte {
+	pos := len(buf)
+	buf = reserveBuffer(buf, len(v)*2)
+
+	for i := 0; i < len(v); i++ {
+		c := v[i]
+		switch c {
+		case '\x00':
+			buf[pos+1] = '0'
+			buf[pos] = '\\'
+			pos += 2
+		case '\n':
+			buf[pos+1] = 'n'
+			buf[pos] = '\\'
+			pos += 2
+		case '\r':
+			buf[pos+1] = 'r'
+			buf[pos] = '\\'
+			pos += 2
+		case '\x1a':
+			buf[pos+1] = 'Z'
+			buf[pos] = '\\'
+			pos += 2
+		case '\'':
+			buf[pos+1] = '\''
+			buf[pos] = '\\'
+			pos += 2
+		case '"':
+			buf[pos+1] = '"'
+			buf[pos] = '\\'
+			pos += 2
+		case '\\':
+			buf[pos+1] = '\\'
+			buf[pos] = '\\'
+			pos += 2
+		default:
+			buf[pos] = c
+			pos++
+		}
+	}
+
+	return buf[:pos]
+}
+
+// escapeBytesQuotes escapes apostrophes in []byte by doubling them up.
+// This escapes the contents of a string by doubling up any apostrophes that
+// it contains. This is used when the NO_BACKSLASH_ESCAPES SQL_MODE is in
+// effect on the server.
+// https://github.com/mysql/mysql-server/blob/mysql-5.7.5/mysys/charset.c#L963-L1038
+func escapeBytesQuotes(buf, v []byte) []byte {
+	pos := len(buf)
+	buf = reserveBuffer(buf, len(v)*2)
+
+	for _, c := range v {
+		if c == '\'' {
+			buf[pos+1] = '\''
+			buf[pos] = '\''
+			pos += 2
+		} else {
+			buf[pos] = c
+			pos++
+		}
+	}
+
+	return buf[:pos]
+}
+
+// escapeStringQuotes is similar to escapeBytesQuotes but for string.
+func escapeStringQuotes(buf []byte, v string) []byte {
+	pos := len(buf)
+	buf = reserveBuffer(buf, len(v)*2)
+
+	for i := 0; i < len(v); i++ {
+		c := v[i]
+		if c == '\'' {
+			buf[pos+1] = '\''
+			buf[pos] = '\''
+			pos += 2
+		} else {
+			buf[pos] = c
+			pos++
+		}
+	}
+
+	return buf[:pos]
+}
+
+/******************************************************************************
+*                               Sync utils                                    *
+******************************************************************************/
+
+// noCopy may be embedded into structs which must not be copied
+// after the first use.
+//
+// See https://github.com/golang/go/issues/8005#issuecomment-190753527
+// for details.
+type noCopy struct{}
+
+// Lock is a no-op used by -copylocks checker from `go vet`.
+func (*noCopy) Lock() {}
+
+// Unlock is a no-op used by -copylocks checker from `go vet`.
+// noCopy should implement sync.Locker from Go 1.11
+// https://github.com/golang/go/commit/c2eba53e7f80df21d51285879d51ab81bcfbf6bc
+// https://github.com/golang/go/issues/26165
+func (*noCopy) Unlock() {}
+
+// atomicBool is a wrapper around uint32 for usage as a boolean value with
+// atomic access.
+type atomicBool struct {
+	_noCopy noCopy
+	value   uint32
+}
+
+// IsSet returns whether the current boolean value is true
+func (ab *atomicBool) IsSet() bool {
+	return atomic.LoadUint32(&ab.value) > 0
+}
+
+// Set sets the value of the bool regardless of the previous value
+func (ab *atomicBool) Set(value bool) {
+	if value {
+		atomic.StoreUint32(&ab.value, 1)
+	} else {
+		atomic.StoreUint32(&ab.value, 0)
+	}
+}
+
+// TrySet sets the value of the bool and returns whether the value changed
+func (ab *atomicBool) TrySet(value bool) bool {
+	if value {
+		return atomic.SwapUint32(&ab.value, 1) == 0
+	}
+	return atomic.SwapUint32(&ab.value, 0) > 0
+}
+
+// atomicError is a wrapper for atomically accessed error values
+type atomicError struct {
+	_noCopy noCopy
+	value   atomic.Value
+}
+
+// Set sets the error value regardless of the previous value.
+// The value must not be nil
+func (ae *atomicError) Set(value error) {
+	ae.value.Store(value)
+}
+
+// Value returns the current error value
+func (ae *atomicError) Value() error {
+	if v := ae.value.Load(); v != nil {
+		// this will panic if the value doesn't implement the error interface
+		return v.(error)
+	}
+	return nil
+}
+
+func namedValueToValue(named []driver.NamedValue) ([]driver.Value, error) {
+	dargs := make([]driver.Value, len(named))
+	for n, param := range named {
+		if len(param.Name) > 0 {
+			// TODO: support the use of Named Parameters #561
+			return nil, errors.New("mysql: driver does not support the use of Named Parameters")
+		}
+		dargs[n] = param.Value
+	}
+	return dargs, nil
+}
+
+func mapIsolationLevel(level driver.IsolationLevel) (string, error) {
+	switch sql.IsolationLevel(level) {
+	case sql.LevelRepeatableRead:
+		return "REPEATABLE READ", nil
+	case sql.LevelReadCommitted:
+		return "READ COMMITTED", nil
+	case sql.LevelReadUncommitted:
+		return "READ UNCOMMITTED", nil
+	case sql.LevelSerializable:
+		return "SERIALIZABLE", nil
+	default:
+		return "", fmt.Errorf("mysql: unsupported isolation level: %v", level)
+	}
+}