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bufio: don't return errors from good Peeks

Fixes #3022

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5674060
This commit is contained in:
Brad Fitzpatrick 2012-02-16 10:15:36 +11:00
parent 3a317183a1
commit 88f8af127a
2 changed files with 27 additions and 3 deletions

View File

@ -106,9 +106,12 @@ func (b *Reader) Peek(n int) ([]byte, error) {
if m > n {
m = n
}
err := b.readErr()
if m < n && err == nil {
err = ErrBufferFull
var err error
if m < n {
err = b.readErr()
if err == nil {
err = ErrBufferFull
}
}
return b.buf[b.r : b.r+m], err
}

View File

@ -539,6 +539,27 @@ func TestPeek(t *testing.T) {
if _, err := buf.Peek(1); err != io.EOF {
t.Fatalf("want EOF got %v", err)
}
// Test for issue 3022, not exposing a reader's error on a successful Peek.
buf = NewReaderSize(dataAndEOFReader("abcd"), 32)
if s, err := buf.Peek(2); string(s) != "ab" || err != nil {
t.Errorf(`Peek(2) on "abcd", EOF = %q, %v; want "ab", nil`, string(s), err)
}
if s, err := buf.Peek(4); string(s) != "abcd" || err != nil {
t.Errorf(`Peek(4) on "abcd", EOF = %q, %v; want "abcd", nil`, string(s), err)
}
if n, err := buf.Read(p[0:5]); string(p[0:n]) != "abcd" || err != nil {
t.Fatalf("Read after peek = %q, %v; want abcd, EOF", p[0:n], err)
}
if n, err := buf.Read(p[0:1]); string(p[0:n]) != "" || err != io.EOF {
t.Fatalf(`second Read after peek = %q, %v; want "", EOF`, p[0:n], err)
}
}
type dataAndEOFReader string
func (r dataAndEOFReader) Read(p []byte) (int, error) {
return copy(p, r), io.EOF
}
func TestPeekThenUnreadRune(t *testing.T) {