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conn.go
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conn.go
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package pq
import (
"bufio"
"bytes"
"context"
"crypto/md5"
"crypto/sha256"
"database/sql"
"database/sql/driver"
"encoding/binary"
"errors"
"fmt"
"io"
"net"
"os"
"os/user"
"path"
"path/filepath"
"strconv"
"strings"
"sync"
"time"
"unicode"
"github.com/lib/pq/oid"
"github.com/lib/pq/scram"
)
// Common error types
var (
ErrNotSupported = errors.New("pq: Unsupported command")
ErrInFailedTransaction = errors.New("pq: Could not complete operation in a failed transaction")
ErrSSLNotSupported = errors.New("pq: SSL is not enabled on the server")
ErrSSLKeyUnknownOwnership = errors.New("pq: Could not get owner information for private key, may not be properly protected")
ErrSSLKeyHasWorldPermissions = errors.New("pq: Private key has world access. Permissions should be u=rw,g=r (0640) if owned by root, or u=rw (0600), or less")
ErrCouldNotDetectUsername = errors.New("pq: Could not detect default username. Please provide one explicitly")
errUnexpectedReady = errors.New("unexpected ReadyForQuery")
errNoRowsAffected = errors.New("no RowsAffected available after the empty statement")
errNoLastInsertID = errors.New("no LastInsertId available after the empty statement")
)
// Compile time validation that our types implement the expected interfaces
var (
_ driver.Driver = Driver{}
)
// Driver is the Postgres database driver.
type Driver struct{}
// Open opens a new connection to the database. name is a connection string.
// Most users should only use it through database/sql package from the standard
// library.
func (d Driver) Open(name string) (driver.Conn, error) {
return Open(name)
}
func init() {
sql.Register("postgres", &Driver{})
}
type parameterStatus struct {
// server version in the same format as server_version_num, or 0 if
// unavailable
serverVersion int
// the current location based on the TimeZone value of the session, if
// available
currentLocation *time.Location
}
type transactionStatus byte
const (
txnStatusIdle transactionStatus = 'I'
txnStatusIdleInTransaction transactionStatus = 'T'
txnStatusInFailedTransaction transactionStatus = 'E'
)
func (s transactionStatus) String() string {
switch s {
case txnStatusIdle:
return "idle"
case txnStatusIdleInTransaction:
return "idle in transaction"
case txnStatusInFailedTransaction:
return "in a failed transaction"
default:
errorf("unknown transactionStatus %d", s)
}
panic("not reached")
}
// Dialer is the dialer interface. It can be used to obtain more control over
// how pq creates network connections.
type Dialer interface {
Dial(network, address string) (net.Conn, error)
DialTimeout(network, address string, timeout time.Duration) (net.Conn, error)
}
// DialerContext is the context-aware dialer interface.
type DialerContext interface {
DialContext(ctx context.Context, network, address string) (net.Conn, error)
}
type defaultDialer struct {
d net.Dialer
}
func (d defaultDialer) Dial(network, address string) (net.Conn, error) {
return d.d.Dial(network, address)
}
func (d defaultDialer) DialTimeout(
network, address string, timeout time.Duration,
) (net.Conn, error) {
ctx, cancel := context.WithTimeout(context.Background(), timeout)
defer cancel()
return d.DialContext(ctx, network, address)
}
func (d defaultDialer) DialContext(ctx context.Context, network, address string) (net.Conn, error) {
return d.d.DialContext(ctx, network, address)
}
type conn struct {
c net.Conn
buf *bufio.Reader
namei int
scratch [512]byte
txnStatus transactionStatus
txnFinish func()
// Save connection arguments to use during CancelRequest.
dialer Dialer
opts values
// Cancellation key data for use with CancelRequest messages.
processID int
secretKey int
parameterStatus parameterStatus
saveMessageType byte
saveMessageBuffer []byte
// If an error is set, this connection is bad and all public-facing
// functions should return the appropriate error by calling get()
// (ErrBadConn) or getForNext().
err syncErr
// If set, this connection should never use the binary format when
// receiving query results from prepared statements. Only provided for
// debugging.
disablePreparedBinaryResult bool
// Whether to always send []byte parameters over as binary. Enables single
// round-trip mode for non-prepared Query calls.
binaryParameters bool
// If true this connection is in the middle of a COPY
inCopy bool
// If not nil, notices will be synchronously sent here
noticeHandler func(*Error)
// If not nil, notifications will be synchronously sent here
notificationHandler func(*Notification)
// GSSAPI context
gss GSS
}
type syncErr struct {
err error
sync.Mutex
}
// Return ErrBadConn if connection is bad.
func (e *syncErr) get() error {
e.Lock()
defer e.Unlock()
if e.err != nil {
return driver.ErrBadConn
}
return nil
}
// Return the error set on the connection. Currently only used by rows.Next.
func (e *syncErr) getForNext() error {
e.Lock()
defer e.Unlock()
return e.err
}
// Set error, only if it isn't set yet.
func (e *syncErr) set(err error) {
if err == nil {
panic("attempt to set nil err")
}
e.Lock()
defer e.Unlock()
if e.err == nil {
e.err = err
}
}
// Handle driver-side settings in parsed connection string.
func (cn *conn) handleDriverSettings(o values) (err error) {
boolSetting := func(key string, val *bool) error {
if value, ok := o[key]; ok {
if value == "yes" {
*val = true
} else if value == "no" {
*val = false
} else {
return fmt.Errorf("unrecognized value %q for %s", value, key)
}
}
return nil
}
err = boolSetting("disable_prepared_binary_result", &cn.disablePreparedBinaryResult)
if err != nil {
return err
}
return boolSetting("binary_parameters", &cn.binaryParameters)
}
func (cn *conn) handlePgpass(o values) {
// if a password was supplied, do not process .pgpass
if _, ok := o["password"]; ok {
return
}
// Get passfile from the options
filename := o["passfile"]
if filename == "" {
// XXX this code doesn't work on Windows where the default filename is
// XXX %APPDATA%\postgresql\pgpass.conf
// Prefer $HOME over user.Current due to glibc bug: golang.org/issue/13470
userHome := os.Getenv("HOME")
if userHome == "" {
user, err := user.Current()
if err != nil {
return
}
userHome = user.HomeDir
}
filename = filepath.Join(userHome, ".pgpass")
}
fileinfo, err := os.Stat(filename)
if err != nil {
return
}
mode := fileinfo.Mode()
if mode&(0x77) != 0 {
// XXX should warn about incorrect .pgpass permissions as psql does
return
}
file, err := os.Open(filename)
if err != nil {
return
}
defer file.Close()
scanner := bufio.NewScanner(io.Reader(file))
// From: https://github.com/tg/pgpass/blob/master/reader.go
for scanner.Scan() {
if scanText(scanner.Text(), o) {
break
}
}
}
// GetFields is a helper function for scanText.
func getFields(s string) []string {
fs := make([]string, 0, 5)
f := make([]rune, 0, len(s))
var esc bool
for _, c := range s {
switch {
case esc:
f = append(f, c)
esc = false
case c == '\\':
esc = true
case c == ':':
fs = append(fs, string(f))
f = f[:0]
default:
f = append(f, c)
}
}
return append(fs, string(f))
}
// ScanText assists HandlePgpass in it's objective.
func scanText(line string, o values) bool {
hostname := o["host"]
ntw, _ := network(o)
port := o["port"]
db := o["dbname"]
username := o["user"]
if len(line) == 0 || line[0] == '#' {
return false
}
split := getFields(line)
if len(split) != 5 {
return false
}
if (split[0] == "*" || split[0] == hostname || (split[0] == "localhost" && (hostname == "" || ntw == "unix"))) && (split[1] == "*" || split[1] == port) && (split[2] == "*" || split[2] == db) && (split[3] == "*" || split[3] == username) {
o["password"] = split[4]
return true
}
return false
}
func (cn *conn) writeBuf(b byte) *writeBuf {
cn.scratch[0] = b
return &writeBuf{
buf: cn.scratch[:5],
pos: 1,
}
}
// Open opens a new connection to the database. dsn is a connection string.
// Most users should only use it through database/sql package from the standard
// library.
func Open(dsn string) (_ driver.Conn, err error) {
return DialOpen(defaultDialer{}, dsn)
}
// DialOpen opens a new connection to the database using a dialer.
func DialOpen(d Dialer, dsn string) (_ driver.Conn, err error) {
c, err := NewConnector(dsn)
if err != nil {
return nil, err
}
c.Dialer(d)
return c.open(context.Background())
}
func (c *Connector) open(ctx context.Context) (cn *conn, err error) {
// Handle any panics during connection initialization. Note that we
// specifically do *not* want to use errRecover(), as that would turn any
// connection errors into ErrBadConns, hiding the real error message from
// the user.
defer errRecoverNoErrBadConn(&err)
// Create a new values map (copy). This makes it so maps in different
// connections do not reference the same underlying data structure, so it
// is safe for multiple connections to concurrently write to their opts.
o := make(values)
for k, v := range c.opts {
o[k] = v
}
cn = &conn{
opts: o,
dialer: c.dialer,
}
err = cn.handleDriverSettings(o)
if err != nil {
return nil, err
}
cn.handlePgpass(o)
cn.c, err = dial(ctx, c.dialer, o)
if err != nil {
return nil, err
}
err = cn.ssl(o)
if err != nil {
if cn.c != nil {
cn.c.Close()
}
return nil, err
}
// cn.startup panics on error. Make sure we don't leak cn.c.
panicking := true
defer func() {
if panicking {
cn.c.Close()
}
}()
cn.buf = bufio.NewReader(cn.c)
cn.startup(o)
// reset the deadline, in case one was set (see dial)
if timeout, ok := o["connect_timeout"]; ok && timeout != "0" {
err = cn.c.SetDeadline(time.Time{})
}
panicking = false
return cn, err
}
func dial(ctx context.Context, d Dialer, o values) (net.Conn, error) {
network, address := network(o)
// Zero or not specified means wait indefinitely.
if timeout, ok := o["connect_timeout"]; ok && timeout != "0" {
seconds, err := strconv.ParseInt(timeout, 10, 0)
if err != nil {
return nil, fmt.Errorf("invalid value for parameter connect_timeout: %s", err)
}
duration := time.Duration(seconds) * time.Second
// connect_timeout should apply to the entire connection establishment
// procedure, so we both use a timeout for the TCP connection
// establishment and set a deadline for doing the initial handshake.
// The deadline is then reset after startup() is done.
deadline := time.Now().Add(duration)
var conn net.Conn
if dctx, ok := d.(DialerContext); ok {
ctx, cancel := context.WithTimeout(ctx, duration)
defer cancel()
conn, err = dctx.DialContext(ctx, network, address)
} else {
conn, err = d.DialTimeout(network, address, duration)
}
if err != nil {
return nil, err
}
err = conn.SetDeadline(deadline)
return conn, err
}
if dctx, ok := d.(DialerContext); ok {
return dctx.DialContext(ctx, network, address)
}
return d.Dial(network, address)
}
func network(o values) (string, string) {
host := o["host"]
if strings.HasPrefix(host, "/") {
sockPath := path.Join(host, ".s.PGSQL."+o["port"])
return "unix", sockPath
}
return "tcp", net.JoinHostPort(host, o["port"])
}
type values map[string]string
// scanner implements a tokenizer for libpq-style option strings.
type scanner struct {
s []rune
i int
}
// newScanner returns a new scanner initialized with the option string s.
func newScanner(s string) *scanner {
return &scanner{[]rune(s), 0}
}
// Next returns the next rune.
// It returns 0, false if the end of the text has been reached.
func (s *scanner) Next() (rune, bool) {
if s.i >= len(s.s) {
return 0, false
}
r := s.s[s.i]
s.i++
return r, true
}
// SkipSpaces returns the next non-whitespace rune.
// It returns 0, false if the end of the text has been reached.
func (s *scanner) SkipSpaces() (rune, bool) {
r, ok := s.Next()
for unicode.IsSpace(r) && ok {
r, ok = s.Next()
}
return r, ok
}
// parseOpts parses the options from name and adds them to the values.
//
// The parsing code is based on conninfo_parse from libpq's fe-connect.c
func parseOpts(name string, o values) error {
s := newScanner(name)
for {
var (
keyRunes, valRunes []rune
r rune
ok bool
)
if r, ok = s.SkipSpaces(); !ok {
break
}
// Scan the key
for !unicode.IsSpace(r) && r != '=' {
keyRunes = append(keyRunes, r)
if r, ok = s.Next(); !ok {
break
}
}
// Skip any whitespace if we're not at the = yet
if r != '=' {
r, ok = s.SkipSpaces()
}
// The current character should be =
if r != '=' || !ok {
return fmt.Errorf(`missing "=" after %q in connection info string"`, string(keyRunes))
}
// Skip any whitespace after the =
if r, ok = s.SkipSpaces(); !ok {
// If we reach the end here, the last value is just an empty string as per libpq.
o[string(keyRunes)] = ""
break
}
if r != '\'' {
for !unicode.IsSpace(r) {
if r == '\\' {
if r, ok = s.Next(); !ok {
return fmt.Errorf(`missing character after backslash`)
}
}
valRunes = append(valRunes, r)
if r, ok = s.Next(); !ok {
break
}
}
} else {
quote:
for {
if r, ok = s.Next(); !ok {
return fmt.Errorf(`unterminated quoted string literal in connection string`)
}
switch r {
case '\'':
break quote
case '\\':
r, _ = s.Next()
fallthrough
default:
valRunes = append(valRunes, r)
}
}
}
o[string(keyRunes)] = string(valRunes)
}
return nil
}
func (cn *conn) isInTransaction() bool {
return cn.txnStatus == txnStatusIdleInTransaction ||
cn.txnStatus == txnStatusInFailedTransaction
}
func (cn *conn) checkIsInTransaction(intxn bool) {
if cn.isInTransaction() != intxn {
cn.err.set(driver.ErrBadConn)
errorf("unexpected transaction status %v", cn.txnStatus)
}
}
func (cn *conn) Begin() (_ driver.Tx, err error) {
return cn.begin("")
}
func (cn *conn) begin(mode string) (_ driver.Tx, err error) {
if err := cn.err.get(); err != nil {
return nil, err
}
defer cn.errRecover(&err)
cn.checkIsInTransaction(false)
_, commandTag, err := cn.simpleExec("BEGIN" + mode)
if err != nil {
return nil, err
}
if commandTag != "BEGIN" {
cn.err.set(driver.ErrBadConn)
return nil, fmt.Errorf("unexpected command tag %s", commandTag)
}
if cn.txnStatus != txnStatusIdleInTransaction {
cn.err.set(driver.ErrBadConn)
return nil, fmt.Errorf("unexpected transaction status %v", cn.txnStatus)
}
return cn, nil
}
func (cn *conn) closeTxn() {
if finish := cn.txnFinish; finish != nil {
finish()
}
}
func (cn *conn) Commit() (err error) {
defer cn.closeTxn()
if err := cn.err.get(); err != nil {
return err
}
defer cn.errRecover(&err)
cn.checkIsInTransaction(true)
// We don't want the client to think that everything is okay if it tries
// to commit a failed transaction. However, no matter what we return,
// database/sql will release this connection back into the free connection
// pool so we have to abort the current transaction here. Note that you
// would get the same behaviour if you issued a COMMIT in a failed
// transaction, so it's also the least surprising thing to do here.
if cn.txnStatus == txnStatusInFailedTransaction {
if err := cn.rollback(); err != nil {
return err
}
return ErrInFailedTransaction
}
_, commandTag, err := cn.simpleExec("COMMIT")
if err != nil {
if cn.isInTransaction() {
cn.err.set(driver.ErrBadConn)
}
return err
}
if commandTag != "COMMIT" {
cn.err.set(driver.ErrBadConn)
return fmt.Errorf("unexpected command tag %s", commandTag)
}
cn.checkIsInTransaction(false)
return nil
}
func (cn *conn) Rollback() (err error) {
defer cn.closeTxn()
if err := cn.err.get(); err != nil {
return err
}
defer cn.errRecover(&err)
return cn.rollback()
}
func (cn *conn) rollback() (err error) {
cn.checkIsInTransaction(true)
_, commandTag, err := cn.simpleExec("ROLLBACK")
if err != nil {
if cn.isInTransaction() {
cn.err.set(driver.ErrBadConn)
}
return err
}
if commandTag != "ROLLBACK" {
return fmt.Errorf("unexpected command tag %s", commandTag)
}
cn.checkIsInTransaction(false)
return nil
}
func (cn *conn) gname() string {
cn.namei++
return strconv.FormatInt(int64(cn.namei), 10)
}
func (cn *conn) simpleExec(q string) (res driver.Result, commandTag string, err error) {
b := cn.writeBuf('Q')
b.string(q)
cn.send(b)
for {
t, r := cn.recv1()
switch t {
case 'C':
res, commandTag = cn.parseComplete(r.string())
case 'Z':
cn.processReadyForQuery(r)
if res == nil && err == nil {
err = errUnexpectedReady
}
// done
return
case 'E':
err = parseError(r)
case 'I':
res = emptyRows
case 'T', 'D':
// ignore any results
default:
cn.err.set(driver.ErrBadConn)
errorf("unknown response for simple query: %q", t)
}
}
}
func (cn *conn) simpleQuery(q string) (res *rows, err error) {
defer cn.errRecover(&err)
b := cn.writeBuf('Q')
b.string(q)
cn.send(b)
for {
t, r := cn.recv1()
switch t {
case 'C', 'I':
// We allow queries which don't return any results through Query as
// well as Exec. We still have to give database/sql a rows object
// the user can close, though, to avoid connections from being
// leaked. A "rows" with done=true works fine for that purpose.
if err != nil {
cn.err.set(driver.ErrBadConn)
errorf("unexpected message %q in simple query execution", t)
}
if res == nil {
res = &rows{
cn: cn,
}
}
// Set the result and tag to the last command complete if there wasn't a
// query already run. Although queries usually return from here and cede
// control to Next, a query with zero results does not.
if t == 'C' {
res.result, res.tag = cn.parseComplete(r.string())
if res.colNames != nil {
return
}
}
res.done = true
case 'Z':
cn.processReadyForQuery(r)
// done
return
case 'E':
res = nil
err = parseError(r)
case 'D':
if res == nil {
cn.err.set(driver.ErrBadConn)
errorf("unexpected DataRow in simple query execution")
}
// the query didn't fail; kick off to Next
cn.saveMessage(t, r)
return
case 'T':
// res might be non-nil here if we received a previous
// CommandComplete, but that's fine; just overwrite it
res = &rows{cn: cn}
res.rowsHeader = parsePortalRowDescribe(r)
// To work around a bug in QueryRow in Go 1.2 and earlier, wait
// until the first DataRow has been received.
default:
cn.err.set(driver.ErrBadConn)
errorf("unknown response for simple query: %q", t)
}
}
}
type noRows struct{}
var emptyRows noRows
var _ driver.Result = noRows{}
func (noRows) LastInsertId() (int64, error) {
return 0, errNoLastInsertID
}
func (noRows) RowsAffected() (int64, error) {
return 0, errNoRowsAffected
}
// Decides which column formats to use for a prepared statement. The input is
// an array of type oids, one element per result column.
func decideColumnFormats(
colTyps []fieldDesc, forceText bool,
) (colFmts []format, colFmtData []byte) {
if len(colTyps) == 0 {
return nil, colFmtDataAllText
}
colFmts = make([]format, len(colTyps))
if forceText {
return colFmts, colFmtDataAllText
}
allBinary := true
allText := true
for i, t := range colTyps {
switch t.OID {
// This is the list of types to use binary mode for when receiving them
// through a prepared statement. If a type appears in this list, it
// must also be implemented in binaryDecode in encode.go.
case oid.T_bytea:
fallthrough
case oid.T_int8:
fallthrough
case oid.T_int4:
fallthrough
case oid.T_int2:
fallthrough
case oid.T_uuid:
colFmts[i] = formatBinary
allText = false
default:
allBinary = false
}
}
if allBinary {
return colFmts, colFmtDataAllBinary
} else if allText {
return colFmts, colFmtDataAllText
} else {
colFmtData = make([]byte, 2+len(colFmts)*2)
binary.BigEndian.PutUint16(colFmtData, uint16(len(colFmts)))
for i, v := range colFmts {
binary.BigEndian.PutUint16(colFmtData[2+i*2:], uint16(v))
}
return colFmts, colFmtData
}
}
func (cn *conn) prepareTo(q, stmtName string) *stmt {
st := &stmt{cn: cn, name: stmtName}
b := cn.writeBuf('P')
b.string(st.name)
b.string(q)
b.int16(0)
b.next('D')
b.byte('S')
b.string(st.name)
b.next('S')
cn.send(b)
cn.readParseResponse()
st.paramTyps, st.colNames, st.colTyps = cn.readStatementDescribeResponse()
st.colFmts, st.colFmtData = decideColumnFormats(st.colTyps, cn.disablePreparedBinaryResult)
cn.readReadyForQuery()
return st
}
func (cn *conn) Prepare(q string) (_ driver.Stmt, err error) {
if err := cn.err.get(); err != nil {
return nil, err
}
defer cn.errRecover(&err)
if len(q) >= 4 && strings.EqualFold(q[:4], "COPY") {
s, err := cn.prepareCopyIn(q)
if err == nil {
cn.inCopy = true
}
return s, err
}
return cn.prepareTo(q, cn.gname()), nil
}
func (cn *conn) Close() (err error) {
// Skip cn.bad return here because we always want to close a connection.
defer cn.errRecover(&err)
// Ensure that cn.c.Close is always run. Since error handling is done with
// panics and cn.errRecover, the Close must be in a defer.
defer func() {
cerr := cn.c.Close()
if err == nil {
err = cerr
}
}()
// Don't go through send(); ListenerConn relies on us not scribbling on the
// scratch buffer of this connection.
return cn.sendSimpleMessage('X')
}
// Implement the "Queryer" interface
func (cn *conn) Query(query string, args []driver.Value) (driver.Rows, error) {
return cn.query(query, args)
}
func (cn *conn) query(query string, args []driver.Value) (_ *rows, err error) {
if err := cn.err.get(); err != nil {
return nil, err
}
if cn.inCopy {
return nil, errCopyInProgress
}
defer cn.errRecover(&err)
// Check to see if we can use the "simpleQuery" interface, which is
// *much* faster than going through prepare/exec
if len(args) == 0 {
return cn.simpleQuery(query)
}
if cn.binaryParameters {
cn.sendBinaryModeQuery(query, args)
cn.readParseResponse()
cn.readBindResponse()
rows := &rows{cn: cn}
rows.rowsHeader = cn.readPortalDescribeResponse()
cn.postExecuteWorkaround()
return rows, nil
}
st := cn.prepareTo(query, "")
st.exec(args)
return &rows{
cn: cn,
rowsHeader: st.rowsHeader,
}, nil
}
// Implement the optional "Execer" interface for one-shot queries
func (cn *conn) Exec(query string, args []driver.Value) (res driver.Result, err error) {
if err := cn.err.get(); err != nil {
return nil, err
}
defer cn.errRecover(&err)
// Check to see if we can use the "simpleExec" interface, which is
// *much* faster than going through prepare/exec
if len(args) == 0 {
// ignore commandTag, our caller doesn't care
r, _, err := cn.simpleExec(query)
return r, err
}
if cn.binaryParameters {
cn.sendBinaryModeQuery(query, args)
cn.readParseResponse()
cn.readBindResponse()
cn.readPortalDescribeResponse()
cn.postExecuteWorkaround()
res, _, err = cn.readExecuteResponse("Execute")
return res, err
}
// Use the unnamed statement to defer planning until bind
// time, or else value-based selectivity estimates cannot be
// used.
st := cn.prepareTo(query, "")
r, err := st.Exec(args)
if err != nil {
panic(err)
}
return r, err
}
type safeRetryError struct {
Err error
}
func (se *safeRetryError) Error() string {
return se.Err.Error()
}
func (cn *conn) send(m *writeBuf) {
n, err := cn.c.Write(m.wrap())
if err != nil {
if n == 0 {
err = &safeRetryError{Err: err}
}
panic(err)
}
}
func (cn *conn) sendStartupPacket(m *writeBuf) error {
_, err := cn.c.Write((m.wrap())[1:])
return err
}
// Send a message of type typ to the server on the other end of cn. The
// message should have no payload. This method does not use the scratch
// buffer.
func (cn *conn) sendSimpleMessage(typ byte) (err error) {
_, err = cn.c.Write([]byte{typ, '\x00', '\x00', '\x00', '\x04'})
return err
}
// saveMessage memorizes a message and its buffer in the conn struct.
// recvMessage will then return these values on the next call to it. This
// method is useful in cases where you have to see what the next message is
// going to be (e.g. to see whether it's an error or not) but you can't handle
// the message yourself.
func (cn *conn) saveMessage(typ byte, buf *readBuf) {
if cn.saveMessageType != 0 {
cn.err.set(driver.ErrBadConn)
errorf("unexpected saveMessageType %d", cn.saveMessageType)