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author | Tim Cooper <tim.cooper@layeh.com> | 2018-10-26 16:34:27 -0500 |
---|---|---|
committer | Brad Fitzpatrick <bradfitz@golang.org> | 2018-10-29 20:07:25 +0000 |
commit | 5fc4604aa8b593d8d9e93c98a1380114633b7c6a (patch) | |
tree | bb9eeeeec7bcce7b36273d3ed417c9ae827e4bf4 /src/bytes | |
parent | 70dd90c4a93d26215a3514d975c2692724d05ac6 (diff) | |
download | go-5fc4604aa8b593d8d9e93c98a1380114633b7c6a.tar.gz go-5fc4604aa8b593d8d9e93c98a1380114633b7c6a.zip |
bytes, strings: fix Reader.UnreadRune returning without error on a zero Reader
Fixes #28269
Change-Id: I878dff43c0b6bdb98702d8e73f2ecd984fb2350f
Reviewed-on: https://go-review.googlesource.com/c/145098
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Diffstat (limited to 'src/bytes')
-rw-r--r-- | src/bytes/reader.go | 6 | ||||
-rw-r--r-- | src/bytes/reader_test.go | 42 |
2 files changed, 47 insertions, 1 deletions
diff --git a/src/bytes/reader.go b/src/bytes/reader.go index 08464c2402..5946cf9780 100644 --- a/src/bytes/reader.go +++ b/src/bytes/reader.go @@ -14,6 +14,7 @@ import ( // io.ByteScanner, and io.RuneScanner interfaces by reading from // a byte slice. // Unlike a Buffer, a Reader is read-only and supports seeking. +// The zero value for Reader operates like a Reader of an empty slice. type Reader struct { s []byte i int64 // current reading index @@ -75,10 +76,10 @@ func (r *Reader) ReadByte() (byte, error) { // UnreadByte complements ReadByte in implementing the io.ByteScanner interface. func (r *Reader) UnreadByte() error { - r.prevRune = -1 if r.i <= 0 { return errors.New("bytes.Reader.UnreadByte: at beginning of slice") } + r.prevRune = -1 r.i-- return nil } @@ -101,6 +102,9 @@ func (r *Reader) ReadRune() (ch rune, size int, err error) { // UnreadRune complements ReadRune in implementing the io.RuneScanner interface. func (r *Reader) UnreadRune() error { + if r.i <= 0 { + return errors.New("bytes.Reader.UnreadRune: at beginning of slice") + } if r.prevRune < 0 { return errors.New("bytes.Reader.UnreadRune: previous operation was not ReadRune") } diff --git a/src/bytes/reader_test.go b/src/bytes/reader_test.go index 8806876ff1..d799e036f0 100644 --- a/src/bytes/reader_test.go +++ b/src/bytes/reader_test.go @@ -276,3 +276,45 @@ func TestReaderReset(t *testing.T) { t.Errorf("ReadAll: got %q, want %q", got, want) } } + +func TestReaderZero(t *testing.T) { + if l := (&Reader{}).Len(); l != 0 { + t.Errorf("Len: got %d, want 0", l) + } + + if n, err := (&Reader{}).Read(nil); n != 0 || err != io.EOF { + t.Errorf("Read: got %d, %v; want 0, io.EOF", n, err) + } + + if n, err := (&Reader{}).ReadAt(nil, 11); n != 0 || err != io.EOF { + t.Errorf("ReadAt: got %d, %v; want 0, io.EOF", n, err) + } + + if b, err := (&Reader{}).ReadByte(); b != 0 || err != io.EOF { + t.Errorf("ReadByte: got %d, %v; want 0, io.EOF", b, err) + } + + if ch, size, err := (&Reader{}).ReadRune(); ch != 0 || size != 0 || err != io.EOF { + t.Errorf("ReadRune: got %d, %d, %v; want 0, 0, io.EOF", ch, size, err) + } + + if offset, err := (&Reader{}).Seek(11, io.SeekStart); offset != 11 || err != nil { + t.Errorf("Seek: got %d, %v; want 11, nil", offset, err) + } + + if s := (&Reader{}).Size(); s != 0 { + t.Errorf("Size: got %d, want 0", s) + } + + if (&Reader{}).UnreadByte() == nil { + t.Errorf("UnreadByte: got nil, want error") + } + + if (&Reader{}).UnreadRune() == nil { + t.Errorf("UnreadRune: got nil, want error") + } + + if n, err := (&Reader{}).WriteTo(ioutil.Discard); n != 0 || err != nil { + t.Errorf("WriteTo: got %d, %v; want 0, nil", n, err) + } +} |