undo CL 86220044 / 41388e58be65

bufio: undo incorrect bug fix

««« original CL description
bufio: fix potential endless loop in ReadByte

Fixes #7745.

LGTM=bradfitz, r
R=r, bradfitz
CC=golang-codereviews
https://golang.org/cl/86220044
»»»

LGTM=adg
R=r, adg
CC=golang-codereviews
https://golang.org/cl/85550045

diff --git a/src/pkg/bufio/bufio.go b/src/pkg/bufio/bufio.go
index 2f51badc9c894ac9bc067107d3109466d58086ff..1e0cdae38e8ebdb862d9a46c6805a9684fc2e356 100644 (file)
--- a/src/pkg/bufio/bufio.go
+++ b/src/pkg/bufio/bufio.go
@@ -88,22 +88,15 @@ func (b *Reader) fill() {
                b.r = 0
        }
 
-       // Read new data: try a limited number of times.
-       for i := maxConsecutiveEmptyReads; i > 0; i-- {
-               n, err := b.rd.Read(b.buf[b.w:])
-               if n < 0 {
-                       panic(errNegativeRead)
-               }
-               b.w += n
-               if err != nil {
-                       b.err = err
-                       return
-               }
-               if n > 0 {
-                       return
-               }
+       // Read new data.
+       n, err := b.rd.Read(b.buf[b.w:])
+       if n < 0 {
+               panic(errNegativeRead)
+       }
+       b.w += n
+       if err != nil {
+               b.err = err
        }
-       b.err = io.ErrNoProgress
 }
 
 func (b *Reader) readErr() error {
@@ -158,9 +151,6 @@ func (b *Reader) Read(p []byte) (n int, err error) {
                        // Large read, empty buffer.
                        // Read directly into p to avoid copy.
                        n, b.err = b.rd.Read(p)
-                       if n < 0 {
-                               panic(errNegativeRead)
-                       }
                        if n > 0 {
                                b.lastByte = int(p[n-1])
                                b.lastRuneSize = -1

diff --git a/src/pkg/bufio/bufio_test.go b/src/pkg/bufio/bufio_test.go
index 406eb153ba11ad08f3ddac3b86fed151e47da644..32ca86161fc0f087f16edd9c0a8d47296c5cba1a 100644 (file)
--- a/src/pkg/bufio/bufio_test.go
+++ b/src/pkg/bufio/bufio_test.go
@@ -14,7 +14,6 @@ import (
        "strings"
        "testing"
        "testing/iotest"
-       "time"
        "unicode/utf8"
 )
 
@@ -175,34 +174,6 @@ func TestReader(t *testing.T) {
        }
 }
 
-type zeroReader struct{}
-
-func (zeroReader) Read(p []byte) (int, error) {
-       return 0, nil
-}
-
-func TestZeroReader(t *testing.T) {
-       var z zeroReader
-       r := NewReader(z)
-
-       c := make(chan error)
-       go func() {
-               _, err := r.ReadByte()
-               c <- err
-       }()
-
-       select {
-       case err := <-c:
-               if err == nil {
-                       t.Error("error expected")
-               } else if err != io.ErrNoProgress {
-                       t.Error("unexpected error:", err)
-               }
-       case <-time.After(time.Second):
-               t.Error("test timed out (endless loop in ReadByte?)")
-       }
-}
-
 // A StringReader delivers its data one string segment at a time via Read.
 type StringReader struct {
        data []string