bufio: handle a "\r\n" that straddles the buffer.
Fixes #2164.
R=r, rsc
CC=golang-dev
https://golang.org/cl/4927043
diff --git a/src/pkg/bufio/bufio.go b/src/pkg/bufio/bufio.go
index 727ebfd..2ea7af3 100644
--- a/src/pkg/bufio/bufio.go
+++ b/src/pkg/bufio/bufio.go
@@ -54,11 +54,11 @@
}
// NewReaderSize creates a new Reader whose buffer has the specified size,
-// which must be greater than zero. If the argument io.Reader is already a
+// which must be greater than one. If the argument io.Reader is already a
// Reader with large enough size, it returns the underlying Reader.
// It returns the Reader and any error.
func NewReaderSize(rd io.Reader, size int) (*Reader, os.Error) {
- if size <= 0 {
+ if size <= 1 {
return nil, BufSizeError(size)
}
// Is it already a Reader?
@@ -298,6 +298,17 @@
func (b *Reader) ReadLine() (line []byte, isPrefix bool, err os.Error) {
line, err = b.ReadSlice('\n')
if err == ErrBufferFull {
+ // Handle the case where "\r\n" straddles the buffer.
+ if len(line) > 0 && line[len(line)-1] == '\r' {
+ // Put the '\r' back on buf and drop it from line.
+ // Let the next call to ReadLine check for "\r\n".
+ if b.r == 0 {
+ // should be unreachable
+ panic("bufio: tried to rewind past start of buffer")
+ }
+ b.r--
+ line = line[:len(line)-1]
+ }
return line, true, nil
}
@@ -307,10 +318,11 @@
err = nil
if line[len(line)-1] == '\n' {
- line = line[:len(line)-1]
- }
- if len(line) > 0 && line[len(line)-1] == '\r' {
- line = line[:len(line)-1]
+ drop := 1
+ if len(line) > 1 && line[len(line)-2] == '\r' {
+ drop = 2
+ }
+ line = line[:len(line)-drop]
}
return
}
diff --git a/src/pkg/bufio/bufio_test.go b/src/pkg/bufio/bufio_test.go
index 82c73d3..38213ff 100644
--- a/src/pkg/bufio/bufio_test.go
+++ b/src/pkg/bufio/bufio_test.go
@@ -137,7 +137,7 @@
}
var bufsizes = []int{
- 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
+ 2, 3, 4, 5, 6, 7, 8, 9, 10,
23, 32, 46, 64, 93, 128, 1024, 4096,
}
@@ -697,3 +697,71 @@
t.Errorf("expected EOF from ReadLine, got '%s' %t %s", line, isPrefix, err)
}
}
+
+type readLineResult struct {
+ line []byte
+ isPrefix bool
+ err os.Error
+}
+
+var readLineNewlinesTests = []struct {
+ input string
+ bufSize int
+ expect []readLineResult
+}{
+ {"h\r\nb\r\n", 2, []readLineResult{
+ {[]byte("h"), true, nil},
+ {nil, false, nil},
+ {[]byte("b"), true, nil},
+ {nil, false, nil},
+ {nil, false, os.EOF},
+ }},
+ {"hello\r\nworld\r\n", 6, []readLineResult{
+ {[]byte("hello"), true, nil},
+ {nil, false, nil},
+ {[]byte("world"), true, nil},
+ {nil, false, nil},
+ {nil, false, os.EOF},
+ }},
+ {"hello\rworld\r", 6, []readLineResult{
+ {[]byte("hello"), true, nil},
+ {[]byte("\rworld"), true, nil},
+ {[]byte("\r"), false, nil},
+ {nil, false, os.EOF},
+ }},
+ {"h\ri\r\n\r", 2, []readLineResult{
+ {[]byte("h"), true, nil},
+ {[]byte("\ri"), true, nil},
+ {nil, false, nil},
+ {[]byte("\r"), false, nil},
+ {nil, false, os.EOF},
+ }},
+}
+
+func TestReadLineNewlines(t *testing.T) {
+ for _, e := range readLineNewlinesTests {
+ testReadLineNewlines(t, e.input, e.bufSize, e.expect)
+ }
+}
+
+func testReadLineNewlines(t *testing.T, input string, bufSize int, expect []readLineResult) {
+ b, err := NewReaderSize(strings.NewReader(input), bufSize)
+ if err != nil {
+ t.Fatal(err)
+ }
+ for i, e := range expect {
+ line, isPrefix, err := b.ReadLine()
+ if bytes.Compare(line, e.line) != 0 {
+ t.Errorf("%q call %d, line == %q, want %q", input, i, line, e.line)
+ return
+ }
+ if isPrefix != e.isPrefix {
+ t.Errorf("%q call %d, isPrefix == %v, want %v", input, i, isPrefix, e.isPrefix)
+ return
+ }
+ if err != e.err {
+ t.Errorf("%q call %d, err == %v, want %v", input, i, err, e.err)
+ return
+ }
+ }
+}
