net/textproto:refactor skipSpace function

Author: cz2h

src/net/textproto/reader.go

@@ -157,7 +157,15 @@ func (r *Reader) readContinuedLineSlice(validateFirstLine func([]byte) error) ([
 	r.buf = append(r.buf[:0], trim(line)...)
 
 	// Read continuation lines.
-	for r.skipSpace() > 0 {
+	for {
+		n, err := r.skipSpace()
+		if n == 0 || err != nil {
+			// If function reads something, it ignores io.EOF.
+			if err == io.EOF && len(r.buf) > 0 {
+				err = nil
+			}
+			return r.buf, err
+		}
 		line, err := r.readLineSlice()
 		if err != nil {
 			break
@@ -169,21 +177,21 @@ func (r *Reader) readContinuedLineSlice(validateFirstLine func([]byte) error) ([
 }
 
 // skipSpace skips R over all spaces and returns the number of bytes skipped.
-func (r *Reader) skipSpace() int {
+func (r *Reader) skipSpace() (int, error) {
 	n := 0
 	for {
 		c, err := r.R.ReadByte()
 		if err != nil {
 			// Bufio will keep err until next read.
-			break
+			return n, err
 		}
 		if c != ' ' && c != '\t' {
 			r.R.UnreadByte()
 			break
 		}
 		n++
 	}
-	return n
+	return n, nil
 }
 
 func (r *Reader) readCodeLine(expectCode int) (code int, continued bool, message string, err error) {