Imported Upstream version 1.1~hg20130304upstream/1.1_hg20130304

1 files changed, 295 insertions, 15 deletions

diff --git a/src/pkg/bufio/bufio_test.go b/src/pkg/bufio/bufio_test.go
index a43cbd23a..b0e811443 100644
--- a/src/pkg/bufio/bufio_test.go
+++ b/src/pkg/bufio/bufio_test.go
@@ -28,9 +28,9 @@ func newRot13Reader(r io.Reader) *rot13Reader {
 }
 
 func (r13 *rot13Reader) Read(p []byte) (int, error) {
-	n, e := r13.r.Read(p)
-	if e != nil {
-		return n, e
+	n, err := r13.r.Read(p)
+	if err != nil {
+		return n, err
 	}
 	for i := 0; i < n; i++ {
 		c := p[i] | 0x20 // lowercase byte
@@ -48,15 +48,15 @@ func readBytes(buf *Reader) string {
 	var b [1000]byte
 	nb := 0
 	for {
-		c, e := buf.ReadByte()
-		if e == io.EOF {
+		c, err := buf.ReadByte()
+		if err == io.EOF {
 			break
 		}
-		if e == nil {
+		if err == nil {
 			b[nb] = c
 			nb++
-		} else if e != iotest.ErrTimeout {
-			panic("Data: " + e.Error())
+		} else if err != iotest.ErrTimeout {
+			panic("Data: " + err.Error())
 		}
 	}
 	return string(b[0:nb])
@@ -93,12 +93,12 @@ var readMakers = []readMaker{
 func readLines(b *Reader) string {
 	s := ""
 	for {
-		s1, e := b.ReadString('\n')
-		if e == io.EOF {
+		s1, err := b.ReadString('\n')
+		if err == io.EOF {
 			break
 		}
-		if e != nil && e != iotest.ErrTimeout {
-			panic("GetLines: " + e.Error())
+		if err != nil && err != iotest.ErrTimeout {
+			panic("GetLines: " + err.Error())
 		}
 		s += s1
 	}
@@ -110,9 +110,9 @@ func reads(buf *Reader, m int) string {
 	var b [1000]byte
 	nb := 0
 	for {
-		n, e := buf.Read(b[nb : nb+m])
+		n, err := buf.Read(b[nb : nb+m])
 		nb += n
-		if e == io.EOF {
+		if err == io.EOF {
 			break
 		}
 	}
@@ -748,7 +748,7 @@ func testReadLineNewlines(t *testing.T, input string, expect []readLineResult) {
 	b := NewReaderSize(strings.NewReader(input), minReadBufferSize)
 	for i, e := range expect {
 		line, isPrefix, err := b.ReadLine()
-		if bytes.Compare(line, e.line) != 0 {
+		if !bytes.Equal(line, e.line) {
 			t.Errorf("%q call %d, line == %q, want %q", input, i, line, e.line)
 			return
 		}
@@ -762,3 +762,283 @@ func testReadLineNewlines(t *testing.T, input string, expect []readLineResult) {
 		}
 	}
 }
+
+func createTestInput(n int) []byte {
+	input := make([]byte, n)
+	for i := range input {
+		// 101 and 251 are arbitrary prime numbers.
+		// The idea is to create an input sequence
+		// which doesn't repeat too frequently.
+		input[i] = byte(i % 251)
+		if i%101 == 0 {
+			input[i] ^= byte(i / 101)
+		}
+	}
+	return input
+}
+
+func TestReaderWriteTo(t *testing.T) {
+	input := createTestInput(8192)
+	r := NewReader(onlyReader{bytes.NewBuffer(input)})
+	w := new(bytes.Buffer)
+	if n, err := r.WriteTo(w); err != nil || n != int64(len(input)) {
+		t.Fatalf("r.WriteTo(w) = %d, %v, want %d, nil", n, err, len(input))
+	}
+
+	for i, val := range w.Bytes() {
+		if val != input[i] {
+			t.Errorf("after write: out[%d] = %#x, want %#x", i, val, input[i])
+		}
+	}
+}
+
+type errorWriterToTest struct {
+	rn, wn     int
+	rerr, werr error
+	expected   error
+}
+
+func (r errorWriterToTest) Read(p []byte) (int, error) {
+	return len(p) * r.rn, r.rerr
+}
+
+func (w errorWriterToTest) Write(p []byte) (int, error) {
+	return len(p) * w.wn, w.werr
+}
+
+var errorWriterToTests = []errorWriterToTest{
+	{1, 0, nil, io.ErrClosedPipe, io.ErrClosedPipe},
+	{0, 1, io.ErrClosedPipe, nil, io.ErrClosedPipe},
+	{0, 0, io.ErrUnexpectedEOF, io.ErrClosedPipe, io.ErrClosedPipe},
+	{0, 1, io.EOF, nil, nil},
+}
+
+func TestReaderWriteToErrors(t *testing.T) {
+	for i, rw := range errorWriterToTests {
+		r := NewReader(rw)
+		if _, err := r.WriteTo(rw); err != rw.expected {
+			t.Errorf("r.WriteTo(errorWriterToTests[%d]) = _, %v, want _,%v", i, err, rw.expected)
+		}
+	}
+}
+
+func TestWriterReadFrom(t *testing.T) {
+	ws := []func(io.Writer) io.Writer{
+		func(w io.Writer) io.Writer { return onlyWriter{w} },
+		func(w io.Writer) io.Writer { return w },
+	}
+
+	rs := []func(io.Reader) io.Reader{
+		iotest.DataErrReader,
+		func(r io.Reader) io.Reader { return r },
+	}
+
+	for ri, rfunc := range rs {
+		for wi, wfunc := range ws {
+			input := createTestInput(8192)
+			b := new(bytes.Buffer)
+			w := NewWriter(wfunc(b))
+			r := rfunc(bytes.NewBuffer(input))
+			if n, err := w.ReadFrom(r); err != nil || n != int64(len(input)) {
+				t.Errorf("ws[%d],rs[%d]: w.ReadFrom(r) = %d, %v, want %d, nil", wi, ri, n, err, len(input))
+				continue
+			}
+			if got, want := b.String(), string(input); got != want {
+				t.Errorf("ws[%d], rs[%d]:\ngot  %q\nwant %q\n", wi, ri, got, want)
+			}
+		}
+	}
+}
+
+type errorReaderFromTest struct {
+	rn, wn     int
+	rerr, werr error
+	expected   error
+}
+
+func (r errorReaderFromTest) Read(p []byte) (int, error) {
+	return len(p) * r.rn, r.rerr
+}
+
+func (w errorReaderFromTest) Write(p []byte) (int, error) {
+	return len(p) * w.wn, w.werr
+}
+
+var errorReaderFromTests = []errorReaderFromTest{
+	{0, 1, io.EOF, nil, nil},
+	{1, 1, io.EOF, nil, nil},
+	{0, 1, io.ErrClosedPipe, nil, io.ErrClosedPipe},
+	{0, 0, io.ErrClosedPipe, io.ErrShortWrite, io.ErrClosedPipe},
+	{1, 0, nil, io.ErrShortWrite, io.ErrShortWrite},
+}
+
+func TestWriterReadFromErrors(t *testing.T) {
+	for i, rw := range errorReaderFromTests {
+		w := NewWriter(rw)
+		if _, err := w.ReadFrom(rw); err != rw.expected {
+			t.Errorf("w.ReadFrom(errorReaderFromTests[%d]) = _, %v, want _,%v", i, err, rw.expected)
+		}
+	}
+}
+
+// TestWriterReadFromCounts tests that using io.Copy to copy into a
+// bufio.Writer does not prematurely flush the buffer. For example, when
+// buffering writes to a network socket, excessive network writes should be
+// avoided.
+func TestWriterReadFromCounts(t *testing.T) {
+	var w0 writeCountingDiscard
+	b0 := NewWriterSize(&w0, 1234)
+	b0.WriteString(strings.Repeat("x", 1000))
+	if w0 != 0 {
+		t.Fatalf("write 1000 'x's: got %d writes, want 0", w0)
+	}
+	b0.WriteString(strings.Repeat("x", 200))
+	if w0 != 0 {
+		t.Fatalf("write 1200 'x's: got %d writes, want 0", w0)
+	}
+	io.Copy(b0, onlyReader{strings.NewReader(strings.Repeat("x", 30))})
+	if w0 != 0 {
+		t.Fatalf("write 1230 'x's: got %d writes, want 0", w0)
+	}
+	io.Copy(b0, onlyReader{strings.NewReader(strings.Repeat("x", 9))})
+	if w0 != 1 {
+		t.Fatalf("write 1239 'x's: got %d writes, want 1", w0)
+	}
+
+	var w1 writeCountingDiscard
+	b1 := NewWriterSize(&w1, 1234)
+	b1.WriteString(strings.Repeat("x", 1200))
+	b1.Flush()
+	if w1 != 1 {
+		t.Fatalf("flush 1200 'x's: got %d writes, want 1", w1)
+	}
+	b1.WriteString(strings.Repeat("x", 89))
+	if w1 != 1 {
+		t.Fatalf("write 1200 + 89 'x's: got %d writes, want 1", w1)
+	}
+	io.Copy(b1, onlyReader{strings.NewReader(strings.Repeat("x", 700))})
+	if w1 != 1 {
+		t.Fatalf("write 1200 + 789 'x's: got %d writes, want 1", w1)
+	}
+	io.Copy(b1, onlyReader{strings.NewReader(strings.Repeat("x", 600))})
+	if w1 != 2 {
+		t.Fatalf("write 1200 + 1389 'x's: got %d writes, want 2", w1)
+	}
+	b1.Flush()
+	if w1 != 3 {
+		t.Fatalf("flush 1200 + 1389 'x's: got %d writes, want 3", w1)
+	}
+}
+
+// A writeCountingDiscard is like ioutil.Discard and counts the number of times
+// Write is called on it.
+type writeCountingDiscard int
+
+func (w *writeCountingDiscard) Write(p []byte) (int, error) {
+	*w++
+	return len(p), nil
+}
+
+type negativeReader int
+
+func (r *negativeReader) Read([]byte) (int, error) { return -1, nil }
+
+func TestNegativeRead(t *testing.T) {
+	// should panic with a description pointing at the reader, not at itself.
+	// (should NOT panic with slice index error, for example.)
+	b := NewReader(new(negativeReader))
+	defer func() {
+		switch err := recover().(type) {
+		case nil:
+			t.Fatal("read did not panic")
+		case error:
+			if !strings.Contains(err.Error(), "reader returned negative count from Read") {
+				t.Fatalf("wrong panic: %v", err)
+			}
+		default:
+			t.Fatalf("unexpected panic value: %T(%v)", err, err)
+		}
+	}()
+	b.Read(make([]byte, 100))
+}
+
+// An onlyReader only implements io.Reader, no matter what other methods the underlying implementation may have.
+type onlyReader struct {
+	r io.Reader
+}
+
+func (r onlyReader) Read(b []byte) (int, error) {
+	return r.r.Read(b)
+}
+
+// An onlyWriter only implements io.Writer, no matter what other methods the underlying implementation may have.
+type onlyWriter struct {
+	w io.Writer
+}
+
+func (w onlyWriter) Write(b []byte) (int, error) {
+	return w.w.Write(b)
+}
+
+func BenchmarkReaderCopyOptimal(b *testing.B) {
+	// Optimal case is where the underlying reader implements io.WriterTo
+	for i := 0; i < b.N; i++ {
+		b.StopTimer()
+		src := NewReader(bytes.NewBuffer(make([]byte, 8192)))
+		dst := onlyWriter{new(bytes.Buffer)}
+		b.StartTimer()
+		io.Copy(dst, src)
+	}
+}
+
+func BenchmarkReaderCopyUnoptimal(b *testing.B) {
+	// Unoptimal case is where the underlying reader doesn't implement io.WriterTo
+	for i := 0; i < b.N; i++ {
+		b.StopTimer()
+		src := NewReader(onlyReader{bytes.NewBuffer(make([]byte, 8192))})
+		dst := onlyWriter{new(bytes.Buffer)}
+		b.StartTimer()
+		io.Copy(dst, src)
+	}
+}
+
+func BenchmarkReaderCopyNoWriteTo(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		b.StopTimer()
+		src := onlyReader{NewReader(bytes.NewBuffer(make([]byte, 8192)))}
+		dst := onlyWriter{new(bytes.Buffer)}
+		b.StartTimer()
+		io.Copy(dst, src)
+	}
+}
+
+func BenchmarkWriterCopyOptimal(b *testing.B) {
+	// Optimal case is where the underlying writer implements io.ReaderFrom
+	for i := 0; i < b.N; i++ {
+		b.StopTimer()
+		src := onlyReader{bytes.NewBuffer(make([]byte, 8192))}
+		dst := NewWriter(new(bytes.Buffer))
+		b.StartTimer()
+		io.Copy(dst, src)
+	}
+}
+
+func BenchmarkWriterCopyUnoptimal(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		b.StopTimer()
+		src := onlyReader{bytes.NewBuffer(make([]byte, 8192))}
+		dst := NewWriter(onlyWriter{new(bytes.Buffer)})
+		b.StartTimer()
+		io.Copy(dst, src)
+	}
+}
+
+func BenchmarkWriterCopyNoReadFrom(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		b.StopTimer()
+		src := onlyReader{bytes.NewBuffer(make([]byte, 8192))}
+		dst := onlyWriter{NewWriter(new(bytes.Buffer))}
+		b.StartTimer()
+		io.Copy(dst, src)
+	}
+}