give bufio.Writer.WriteString the same signature as

bytes.Buffer.WriteString

Fixes #535.

R=rsc
CC=golang-dev
https://golang.org/cl/189096

diff --git a/src/pkg/bufio/bufio.go b/src/pkg/bufio/bufio.go
index 00bc53cd73769b56f39dd3894ac4a4a95c3fc1d6..7b7f25831ea3cb9b4233d4a570070ee9af8a96fc 100644 (file)
--- a/src/pkg/bufio/bufio.go
+++ b/src/pkg/bufio/bufio.go
@@ -387,7 +387,7 @@ func (b *Writer) Buffered() int { return b.n }
 
 // Write writes the contents of p into the buffer.
 // It returns the number of bytes written.
-// If nn < len(p), also returns an error explaining
+// If nn < len(p), it also returns an error explaining
 // why the write is short.
 func (b *Writer) Write(p []byte) (nn int, err os.Error) {
        if b.err != nil {
@@ -438,9 +438,12 @@ func (b *Writer) WriteByte(c byte) os.Error {
 }
 
 // WriteString writes a string.
-func (b *Writer) WriteString(s string) os.Error {
+// It returns the number of bytes written.
+// If the count is less than len(s), it also returns an error explaining
+// why the write is short.
+func (b *Writer) WriteString(s string) (int, os.Error) {
        if b.err != nil {
-               return b.err
+               return 0, b.err
        }
        // Common case, worth making fast.
        if b.Available() >= len(s) || len(b.buf) >= len(s) && b.Flush() == nil {
@@ -448,12 +451,15 @@ func (b *Writer) WriteString(s string) os.Error {
                        b.buf[b.n] = s[i]
                        b.n++
                }
-               return nil
+               return len(s), nil
        }
        for i := 0; i < len(s); i++ { // loop over bytes, not runes.
                b.WriteByte(s[i])
+               if b.err != nil {
+                       return i, b.err
+               }
        }
-       return b.err
+       return len(s), nil
 }
 
 // buffered input and output