outbuf [1024 / 8 * 5]byte
}
-func (d *decoder) Read(p []byte) (n int, err error) {
- if d.err != nil {
- return 0, d.err
+func readEncodedData(r io.Reader, buf []byte, min int) (n int, err error) {
+ for n < min && err == nil {
+ var nn int
+ nn, err = r.Read(buf[n:])
+ n += nn
+ }
+ if n < min && n > 0 && err == io.EOF {
+ err = io.ErrUnexpectedEOF
}
+ return
+}
+func (d *decoder) Read(p []byte) (n int, err error) {
// Use leftover decoded output from last read.
if len(d.out) > 0 {
n = copy(p, d.out)
d.out = d.out[n:]
+ if len(d.out) == 0 {
+ return n, d.err
+ }
return n, nil
}
+ if d.err != nil {
+ return 0, d.err
+ }
+
// Read a chunk.
nn := len(p) / 5 * 8
if nn < 8 {
if nn > len(d.buf) {
nn = len(d.buf)
}
- nn, d.err = io.ReadAtLeast(d.r, d.buf[d.nbuf:nn], 8-d.nbuf)
+
+ nn, d.err = readEncodedData(d.r, d.buf[d.nbuf:nn], 8-d.nbuf)
d.nbuf += nn
if d.nbuf < 8 {
return 0, d.err
nr := d.nbuf / 8 * 8
nw := d.nbuf / 8 * 5
if nw > len(p) {
- nw, d.end, d.err = d.enc.decode(d.outbuf[0:], d.buf[0:nr])
+ nw, d.end, err = d.enc.decode(d.outbuf[0:], d.buf[0:nr])
d.out = d.outbuf[0:nw]
n = copy(p, d.out)
d.out = d.out[n:]
} else {
- n, d.end, d.err = d.enc.decode(p, d.buf[0:nr])
+ n, d.end, err = d.enc.decode(p, d.buf[0:nr])
}
d.nbuf -= nr
for i := 0; i < d.nbuf; i++ {
d.buf[i] = d.buf[i+nr]
}
- if d.err == nil {
+ if err != nil && (d.err == nil || d.err == io.EOF) {
d.err = err
}
+
+ if len(d.out) > 0 {
+ // We cannot return all the decoded bytes to the caller in this
+ // invocation of Read, so we return a nil error to ensure that Read
+ // will be called again. The error stored in d.err, if any, will be
+ // returned with the last set of decoded bytes.
+ return n, nil
+ }
+
return n, d.err
}
offset++
}
}
- if offset > 0 {
+ if err != nil || offset > 0 {
return offset, err
}
// Previous buffer entirely whitespace, read again
import (
"bytes"
+ "errors"
"io"
"io/ioutil"
"strings"
}
}
+type badReader struct {
+ data []byte
+ errs []error
+ called int
+ limit int
+}
+
+// Populates p with data, returns a count of the bytes written and an
+// error. The error returned is taken from badReader.errs, with each
+// invocation of Read returning the next error in this slice, or io.EOF,
+// if all errors from the slice have already been returned. The
+// number of bytes returned is determined by the size of the input buffer
+// the test passes to decoder.Read and will be a multiple of 8, unless
+// badReader.limit is non zero.
+func (b *badReader) Read(p []byte) (int, error) {
+ lim := len(p)
+ if b.limit != 0 && b.limit < lim {
+ lim = b.limit
+ }
+ if len(b.data) < lim {
+ lim = len(b.data)
+ }
+ for i := range p[:lim] {
+ p[i] = b.data[i]
+ }
+ b.data = b.data[lim:]
+ err := io.EOF
+ if b.called < len(b.errs) {
+ err = b.errs[b.called]
+ }
+ b.called++
+ return lim, err
+}
+
+// TestIssue20044 tests that decoder.Read behaves correctly when the caller
+// supplied reader returns an error.
+func TestIssue20044(t *testing.T) {
+ badErr := errors.New("bad reader error")
+ testCases := []struct {
+ r badReader
+ res string
+ err error
+ dbuflen int
+ }{
+ // Check valid input data accompanied by an error is processed and the error is propagated.
+ {r: badReader{data: []byte("MY======"), errs: []error{badErr}},
+ res: "f", err: badErr},
+ // Check a read error accompanied by input data consisting of newlines only is propagated.
+ {r: badReader{data: []byte("\n\n\n\n\n\n\n\n"), errs: []error{badErr, nil}},
+ res: "", err: badErr},
+ // Reader will be called twice. The first time it will return 8 newline characters. The
+ // second time valid base32 encoded data and an error. The data should be decoded
+ // correctly and the error should be propagated.
+ {r: badReader{data: []byte("\n\n\n\n\n\n\n\nMY======"), errs: []error{nil, badErr}},
+ res: "f", err: badErr, dbuflen: 8},
+ // Reader returns invalid input data (too short) and an error. Verify the reader
+ // error is returned.
+ {r: badReader{data: []byte("MY====="), errs: []error{badErr}},
+ res: "", err: badErr},
+ // Reader returns invalid input data (too short) but no error. Verify io.ErrUnexpectedEOF
+ // is returned.
+ {r: badReader{data: []byte("MY====="), errs: []error{nil}},
+ res: "", err: io.ErrUnexpectedEOF},
+ // Reader returns invalid input data and an error. Verify the reader and not the
+ // decoder error is returned.
+ {r: badReader{data: []byte("Ma======"), errs: []error{badErr}},
+ res: "", err: badErr},
+ // Reader returns valid data and io.EOF. Check data is decoded and io.EOF is propagated.
+ {r: badReader{data: []byte("MZXW6YTB"), errs: []error{io.EOF}},
+ res: "fooba", err: io.EOF},
+ // Check errors are properly reported when decoder.Read is called multiple times.
+ // decoder.Read will be called 8 times, badReader.Read will be called twice, returning
+ // valid data both times but an error on the second call.
+ {r: badReader{data: []byte("NRSWC43VOJSS4==="), errs: []error{nil, badErr}},
+ res: "leasure.", err: badErr, dbuflen: 1},
+ // Check io.EOF is properly reported when decoder.Read is called multiple times.
+ // decoder.Read will be called 8 times, badReader.Read will be called twice, returning
+ // valid data both times but io.EOF on the second call.
+ {r: badReader{data: []byte("NRSWC43VOJSS4==="), errs: []error{nil, io.EOF}},
+ res: "leasure.", err: io.EOF, dbuflen: 1},
+ // The following two test cases check that errors are propagated correctly when more than
+ // 8 bytes are read at a time.
+ {r: badReader{data: []byte("NRSWC43VOJSS4==="), errs: []error{io.EOF}},
+ res: "leasure.", err: io.EOF, dbuflen: 11},
+ {r: badReader{data: []byte("NRSWC43VOJSS4==="), errs: []error{badErr}},
+ res: "leasure.", err: badErr, dbuflen: 11},
+ // Check that errors are correctly propagated when the reader returns valid bytes in
+ // groups that are not divisible by 8. The first read will return 11 bytes and no
+ // error. The second will return 7 and an error. The data should be decoded correctly
+ // and the error should be propagated.
+ {r: badReader{data: []byte("NRSWC43VOJSS4==="), errs: []error{nil, badErr}, limit: 11},
+ res: "leasure.", err: badErr},
+ }
+
+ for _, tc := range testCases {
+ input := tc.r.data
+ decoder := NewDecoder(StdEncoding, &tc.r)
+ var dbuflen int
+ if tc.dbuflen > 0 {
+ dbuflen = tc.dbuflen
+ } else {
+ dbuflen = StdEncoding.DecodedLen(len(input))
+ }
+ dbuf := make([]byte, dbuflen)
+ var err error
+ var res []byte
+ for err == nil {
+ var n int
+ n, err = decoder.Read(dbuf)
+ if n > 0 {
+ res = append(res, dbuf[:n]...)
+ }
+ }
+
+ testEqual(t, "Decoding of %q = %q, want %q", string(input), string(res), tc.res)
+ testEqual(t, "Decoding of %q err = %v, expected %v", string(input), err, tc.err)
+ }
+}
+
+// TestDecoderError verifies decode errors are propagated when there are no read
+// errors.
+func TestDecoderError(t *testing.T) {
+ for _, readErr := range []error{io.EOF, nil} {
+ input := "MZXW6YTb"
+ dbuf := make([]byte, StdEncoding.DecodedLen(len(input)))
+ br := badReader{data: []byte(input), errs: []error{readErr}}
+ decoder := NewDecoder(StdEncoding, &br)
+ n, err := decoder.Read(dbuf)
+ testEqual(t, "Read after EOF, n = %d, expected %d", n, 0)
+ if _, ok := err.(CorruptInputError); !ok {
+ t.Errorf("Corrupt input error expected. Found %T", err)
+ }
+ }
+}
+
+// TestReaderEOF ensures decoder.Read behaves correctly when input data is
+// exhausted.
+func TestReaderEOF(t *testing.T) {
+ for _, readErr := range []error{io.EOF, nil} {
+ input := "MZXW6YTB"
+ br := badReader{data: []byte(input), errs: []error{nil, readErr}}
+ decoder := NewDecoder(StdEncoding, &br)
+ dbuf := make([]byte, StdEncoding.DecodedLen(len(input)))
+ n, err := decoder.Read(dbuf)
+ testEqual(t, "Decoding of %q err = %v, expected %v", string(input), err, error(nil))
+ n, err = decoder.Read(dbuf)
+ testEqual(t, "Read after EOF, n = %d, expected %d", n, 0)
+ testEqual(t, "Read after EOF, err = %v, expected %v", err, io.EOF)
+ n, err = decoder.Read(dbuf)
+ testEqual(t, "Read after EOF, n = %d, expected %d", n, 0)
+ testEqual(t, "Read after EOF, err = %v, expected %v", err, io.EOF)
+ }
+}
+
func TestDecoderBuffering(t *testing.T) {
for bs := 1; bs <= 12; bs++ {
decoder := NewDecoder(StdEncoding, strings.NewReader(bigtest.encoded))