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encoding/hex: fix potential incorrect Dumper output when Close is called multiple times

Fixes #23574

Change-Id: I69573de47daa6fd53cc99a78c0c4b867460242e3
Reviewed-on: https://go-review.googlesource.com/90275
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
This commit is contained in:
Tim Cooper 2018-01-26 16:36:15 -04:00 committed by Brad Fitzpatrick
parent 755b36aa53
commit 0519126a3f
2 changed files with 23 additions and 1 deletions

View File

@ -211,6 +211,7 @@ type dumper struct {
buf [14]byte
used int // number of bytes in the current line
n uint // number of bytes, total
closed bool
}
func toChar(b byte) byte {
@ -221,6 +222,10 @@ func toChar(b byte) byte {
}
func (h *dumper) Write(data []byte) (n int, err error) {
if h.closed {
return 0, errors.New("encoding/hex: dumper closed")
}
// Output lines look like:
// 00000010 2e 2f 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d |./0123456789:;<=|
// ^ offset ^ extra space ^ ASCII of line.
@ -277,9 +282,10 @@ func (h *dumper) Write(data []byte) (n int, err error) {
func (h *dumper) Close() (err error) {
// See the comments in Write() for the details of this format.
if h.used == 0 {
if h.used == 0 || h.closed {
return
}
h.closed = true
h.buf[0] = ' '
h.buf[1] = ' '
h.buf[2] = ' '

View File

@ -188,6 +188,22 @@ func TestDumper(t *testing.T) {
}
}
func TestDumper_doubleclose(t *testing.T) {
var out bytes.Buffer
dumper := Dumper(&out)
dumper.Write([]byte(`gopher`))
dumper.Close()
dumper.Close()
dumper.Write([]byte(`gopher`))
dumper.Close()
expected := "00000000 67 6f 70 68 65 72 |gopher|\n"
if out.String() != expected {
t.Fatalf("got:\n%#v\nwant:\n%#v", out.String(), expected)
}
}
func TestDump(t *testing.T) {
var in [40]byte
for i := range in {