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Commit bb7b1a11 authored by Rob Pike's avatar Rob Pike
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bufio: drop error return for NewReaderSize and NewWriterSize 

It complicates the interface unnecessarily.
Document this in go1.html.
Also update the go/doc Makefile.

Fixes #2836.

R=golang-dev, gri, bradfitz
CC=golang-dev
https://golang.org/cl/5642054
parent 518ee115
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Showing with 81 additions and 108 deletions
doc/Makefile
View file @ bb7b1a11
......@@ -2,12 +2,6 @@
# Use of this source code is governed by a BSD-style
# license that can be found in the LICENSE file.
include ../src/Make.inc
TARG=tmpltohtml
GOFILES=\
tmpltohtml.go\
HTML=\
articles/defer_panic_recover.html\
articles/error_handling.html\
......@@ -18,7 +12,8 @@ HTML=\
all: tmpltohtml $(HTML)
tmpltohtml: tmpltohtml.go
go build tmpltohtml.go
%.html: %.tmpl tmpltohtml
./makehtml $*.tmpl
include ../src/Make.cmd
doc/go1.html
View file @ bb7b1a11
......@@ -863,6 +863,22 @@ few programs beyond the need to run <code>go fix</code>.
This category includes packages that are new in Go 1.
</p>
<h3 id="bufio">The bufio package</h3>
<p>
In Go 1, <a href="/pkg/bufio/#NewReaderSize"><code>bufio.NewReaderSize</code></a>
and
<a href="/pkg/bufio/#NewWriterSize"><code>bufio.NewWriterSize</code></a>
functions no longer return an error for invalid sizes.
If the argument size is too small or invalid, it is adjusted.
</p>
<p>
<em>Updating</em>:
These functions are rarely used, and code must be updated by hand.
All that is required is to drop the second return value.
</p>
<h3 id="crypto_elliptic">The crypto/elliptic package</h3>
<p>
......
doc/go1.tmpl
View file @ bb7b1a11
......@@ -767,6 +767,22 @@ few programs beyond the need to run <code>go fix</code>.
This category includes packages that are new in Go 1.
</p>
<h3 id="bufio">The bufio package</h3>
<p>
In Go 1, <a href="/pkg/bufio/#NewReaderSize"><code>bufio.NewReaderSize</code></a>
and
<a href="/pkg/bufio/#NewWriterSize"><code>bufio.NewWriterSize</code></a>
functions no longer return an error for invalid sizes.
If the argument size is too small or invalid, it is adjusted.
</p>
<p>
<em>Updating</em>:
These functions are rarely used, and code must be updated by hand.
All that is required is to drop the second return value.
</p>
<h3 id="crypto_elliptic">The crypto/elliptic package</h3>
<p>
......
src/pkg/bufio/bufio.go
View file @ bb7b1a11
......@@ -11,7 +11,6 @@ import (
"bytes"
"errors"
"io"
"strconv"
"unicode/utf8"
)
......@@ -27,13 +26,6 @@ var (
errInternal = errors.New("bufio: internal error")
)
// BufSizeError is the error representing an invalid buffer size.
type BufSizeError int
func (b BufSizeError) Error() string {
return "bufio: bad buffer size " + strconv.Itoa(int(b))
}
// Buffered input.
// Reader implements buffering for an io.Reader object.
......@@ -48,35 +40,29 @@ type Reader struct {
const minReadBufferSize = 16
// NewReaderSize creates a new Reader whose buffer has the specified size,
// which must be at least 16 bytes. 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, error) {
if size < minReadBufferSize {
return nil, BufSizeError(size)
}
// NewReaderSize returns a new Reader whose buffer has at least the specified
// size. If the argument io.Reader is already a Reader with large enough
// size, it returns the underlying Reader.
func NewReaderSize(rd io.Reader, size int) *Reader {
// Is it already a Reader?
b, ok := rd.(*Reader)
if ok && len(b.buf) >= size {
return b, nil
return b
}
if size < minReadBufferSize {
size = minReadBufferSize
}
return &Reader{
buf: make([]byte, size),
rd: rd,
lastByte: -1,
lastRuneSize: -1,
}
b = new(Reader)
b.buf = make([]byte, size)
b.rd = rd
b.lastByte = -1
b.lastRuneSize = -1
return b, nil
}
// NewReader returns a new Reader whose buffer has the default size.
func NewReader(rd io.Reader) *Reader {
b, err := NewReaderSize(rd, defaultBufSize)
if err != nil {
// cannot happen - defaultBufSize is a valid size
panic(err)
}
return b
return NewReaderSize(rd, defaultBufSize)
}
// fill reads a new chunk into the buffer.
......@@ -396,33 +382,27 @@ type Writer struct {
wr io.Writer
}
// NewWriterSize creates a new Writer whose buffer has the specified size,
// which must be greater than zero. If the argument io.Writer is already a
// Writer with large enough size, it returns the underlying Writer.
// It returns the Writer and any error.
func NewWriterSize(wr io.Writer, size int) (*Writer, error) {
if size <= 0 {
return nil, BufSizeError(size)
}
// NewWriterSize returns a new Writer whose buffer has at least the specified
// size. If the argument io.Writer is already a Writer with large enough
// size, it returns the underlying Writer.
func NewWriterSize(wr io.Writer, size int) *Writer {
// Is it already a Writer?
b, ok := wr.(*Writer)
if ok && len(b.buf) >= size {
return b, nil
return b
}
if size <= 0 {
size = defaultBufSize
}
b = new(Writer)
b.buf = make([]byte, size)
b.wr = wr
return b, nil
return b
}
// NewWriter returns a new Writer whose buffer has the default size.
func NewWriter(wr io.Writer) *Writer {
b, err := NewWriterSize(wr, defaultBufSize)
if err != nil {
// cannot happen - defaultBufSize is valid size
panic(err)
}
return b
return NewWriterSize(wr, defaultBufSize)
}
// Flush writes any buffered data to the underlying io.Writer.
......
src/pkg/bufio/bufio_test.go
View file @ bb7b1a11
......@@ -161,7 +161,7 @@ func TestReader(t *testing.T) {
bufreader := bufreaders[j]
bufsize := bufsizes[k]
read := readmaker.fn(bytes.NewBufferString(text))
buf, _ := NewReaderSize(read, bufsize)
buf := NewReaderSize(read, bufsize)
s := bufreader.fn(buf)
if s != text {
t.Errorf("reader=%s fn=%s bufsize=%d want=%q got=%q",
......@@ -379,18 +379,14 @@ func TestWriter(t *testing.T) {
// and that the data is correct.
w.Reset()
buf, e := NewWriterSize(w, bs)
buf := NewWriterSize(w, bs)
context := fmt.Sprintf("nwrite=%d bufsize=%d", nwrite, bs)
if e != nil {
t.Errorf("%s: NewWriterSize %d: %v", context, bs, e)
continue
}
n, e1 := buf.Write(data[0:nwrite])
if e1 != nil || n != nwrite {
t.Errorf("%s: buf.Write %d = %d, %v", context, nwrite, n, e1)
continue
}
if e = buf.Flush(); e != nil {
if e := buf.Flush(); e != nil {
t.Errorf("%s: buf.Flush = %v", context, e)
}
......@@ -447,23 +443,14 @@ func TestWriteErrors(t *testing.T) {
func TestNewReaderSizeIdempotent(t *testing.T) {
const BufSize = 1000
b, err := NewReaderSize(bytes.NewBufferString("hello world"), BufSize)
if err != nil {
t.Error("NewReaderSize create fail", err)
}
b := NewReaderSize(bytes.NewBufferString("hello world"), BufSize)
// Does it recognize itself?
b1, err2 := NewReaderSize(b, BufSize)
if err2 != nil {
t.Error("NewReaderSize #2 create fail", err2)
}
b1 := NewReaderSize(b, BufSize)
if b1 != b {
t.Error("NewReaderSize did not detect underlying Reader")
}
// Does it wrap if existing buffer is too small?
b2, err3 := NewReaderSize(b, 2*BufSize)
if err3 != nil {
t.Error("NewReaderSize #3 create fail", err3)
}
b2 := NewReaderSize(b, 2*BufSize)
if b2 == b {
t.Error("NewReaderSize did not enlarge buffer")
}
......@@ -471,23 +458,14 @@ func TestNewReaderSizeIdempotent(t *testing.T) {
func TestNewWriterSizeIdempotent(t *testing.T) {
const BufSize = 1000
b, err := NewWriterSize(new(bytes.Buffer), BufSize)
if err != nil {
t.Error("NewWriterSize create fail", err)
}
b := NewWriterSize(new(bytes.Buffer), BufSize)
// Does it recognize itself?
b1, err2 := NewWriterSize(b, BufSize)
if err2 != nil {
t.Error("NewWriterSize #2 create fail", err2)
}
b1 := NewWriterSize(b, BufSize)
if b1 != b {
t.Error("NewWriterSize did not detect underlying Writer")
}
// Does it wrap if existing buffer is too small?
b2, err3 := NewWriterSize(b, 2*BufSize)
if err3 != nil {
t.Error("NewWriterSize #3 create fail", err3)
}
b2 := NewWriterSize(b, 2*BufSize)
if b2 == b {
t.Error("NewWriterSize did not enlarge buffer")
}
......@@ -496,10 +474,7 @@ func TestNewWriterSizeIdempotent(t *testing.T) {
func TestWriteString(t *testing.T) {
const BufSize = 8
buf := new(bytes.Buffer)
b, err := NewWriterSize(buf, BufSize)
if err != nil {
t.Error("NewWriterSize create fail", err)
}
b := NewWriterSize(buf, BufSize)
b.WriteString("0") // easy
b.WriteString("123456") // still easy
b.WriteString("7890") // easy after flush
......@@ -516,10 +491,7 @@ func TestWriteString(t *testing.T) {
func TestBufferFull(t *testing.T) {
const longString = "And now, hello, world! It is the time for all good men to come to the aid of their party"
buf, err := NewReaderSize(strings.NewReader(longString), minReadBufferSize)
if err != nil {
t.Fatal("NewReaderSize:", err)
}
buf := NewReaderSize(strings.NewReader(longString), minReadBufferSize)
line, err := buf.ReadSlice('!')
if string(line) != "And now, hello, " || err != ErrBufferFull {
t.Errorf("first ReadSlice(,) = %q, %v", line, err)
......@@ -533,7 +505,7 @@ func TestBufferFull(t *testing.T) {
func TestPeek(t *testing.T) {
p := make([]byte, 10)
// string is 16 (minReadBufferSize) long.
buf, _ := NewReaderSize(strings.NewReader("abcdefghijklmnop"), minReadBufferSize)
buf := NewReaderSize(strings.NewReader("abcdefghijklmnop"), minReadBufferSize)
if s, err := buf.Peek(1); string(s) != "a" || err != nil {
t.Fatalf("want %q got %q, err=%v", "a", string(s), err)
}
......@@ -609,7 +581,7 @@ func testReadLine(t *testing.T, input []byte) {
for stride := 1; stride < 2; stride++ {
done := 0
reader := testReader{input, stride}
l, _ := NewReaderSize(&reader, len(input)+1)
l := NewReaderSize(&reader, len(input)+1)
for {
line, isPrefix, err := l.ReadLine()
if len(line) > 0 && err != nil {
......@@ -646,7 +618,7 @@ func TestLineTooLong(t *testing.T) {
data = append(data, '0'+byte(i%10))
}
buf := bytes.NewBuffer(data)
l, _ := NewReaderSize(buf, minReadBufferSize)
l := NewReaderSize(buf, minReadBufferSize)
line, isPrefix, err := l.ReadLine()
if !isPrefix || !bytes.Equal(line, data[:minReadBufferSize]) || err != nil {
t.Errorf("bad result for first line: got %q want %q %v", line, data[:minReadBufferSize], err)
......@@ -673,7 +645,7 @@ func TestReadAfterLines(t *testing.T) {
inbuf := bytes.NewBuffer([]byte(line1 + "\n" + restData))
outbuf := new(bytes.Buffer)
maxLineLength := len(line1) + len(restData)/2
l, _ := NewReaderSize(inbuf, maxLineLength)
l := NewReaderSize(inbuf, maxLineLength)
line, isPrefix, err := l.ReadLine()
if isPrefix || err != nil || string(line) != line1 {
t.Errorf("bad result for first line: isPrefix=%v err=%v line=%q", isPrefix, err, string(line))
......@@ -688,7 +660,7 @@ func TestReadAfterLines(t *testing.T) {
}
func TestReadEmptyBuffer(t *testing.T) {
l, _ := NewReaderSize(new(bytes.Buffer), minReadBufferSize)
l := NewReaderSize(new(bytes.Buffer), minReadBufferSize)
line, isPrefix, err := l.ReadLine()
if err != io.EOF {
t.Errorf("expected EOF from ReadLine, got '%s' %t %s", line, isPrefix, err)
......@@ -696,7 +668,7 @@ func TestReadEmptyBuffer(t *testing.T) {
}
func TestLinesAfterRead(t *testing.T) {
l, _ := NewReaderSize(bytes.NewBuffer([]byte("foo")), minReadBufferSize)
l := NewReaderSize(bytes.NewBuffer([]byte("foo")), minReadBufferSize)
_, err := ioutil.ReadAll(l)
if err != nil {
t.Error(err)
......@@ -752,10 +724,7 @@ func TestReadLineNewlines(t *testing.T) {
}
func testReadLineNewlines(t *testing.T, input string, expect []readLineResult) {
b, err := NewReaderSize(strings.NewReader(input), minReadBufferSize)
if err != nil {
t.Fatal(err)
}
b := NewReaderSize(strings.NewReader(input), minReadBufferSize)
for i, e := range expect {
line, isPrefix, err := b.ReadLine()
if bytes.Compare(line, e.line) != 0 {
......
src/pkg/image/png/writer.go
View file @ bb7b1a11
......@@ -408,10 +408,7 @@ func (e *encoder) writeIDATs() {
return
}
var bw *bufio.Writer
bw, e.err = bufio.NewWriterSize(e, 1<<15)
if e.err != nil {
return
}
bw = bufio.NewWriterSize(e, 1<<15)
e.err = writeImage(bw, e.m, e.cb)
if e.err != nil {
return
......
src/pkg/net/http/cgi/host.go
View file @ bb7b1a11
......@@ -217,7 +217,7 @@ func (h *Handler) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
defer cmd.Wait()
defer stdoutRead.Close()
linebody, _ := bufio.NewReaderSize(stdoutRead, 1024)
linebody := bufio.NewReaderSize(stdoutRead, 1024)
headers := make(http.Header)
statusCode := 0
for {
......
src/pkg/net/http/fcgi/fcgi.go
View file @ bb7b1a11
......@@ -240,7 +240,7 @@ func (w *bufWriter) Close() error {
func newWriter(c *conn, recType recType, reqId uint16) *bufWriter {
s := &streamWriter{c: c, recType: recType, reqId: reqId}
w, _ := bufio.NewWriterSize(s, maxWrite)
w := bufio.NewWriterSize(s, maxWrite)
return &bufWriter{s, w}
}
......
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