net: parser should handle EOF without newline properly.

Fixes #686.

R=rsc
CC=adg, golang-dev
https://golang.org/cl/979044

src/pkg/net/parse.go

@@ -13,31 +13,32 @@ import (
 )
 
 type file struct {
-	file *os.File
-	data []byte
+	file  *os.File
+	data  []byte
+	atEOF bool
 }
 
 func (f *file) close() { f.file.Close() }
 
 func (f *file) getLineFromData() (s string, ok bool) {
 	data := f.data
-	for i := 0; i < len(data); i++ {
+	i := 0
+	for i = 0; i < len(data); i++ {
 		if data[i] == '\n' {
 			s = string(data[0:i])
 			ok = true
 			// move data
 			i++
 			n := len(data) - i
-			for j := 0; j < n; j++ {
-				data[j] = data[i+j]
-			}
+			copy(data[0:], data[i:])
 			f.data = data[0:n]
 			return
 		}
 	}
-	if len(f.data) > 0 {
+	if f.atEOF && len(f.data) > 0 {
+		// EOF, return all we have
 		s = string(data)
-		f.data = nil
+		f.data = f.data[0:0]
 		ok = true
 	}
 	return
@@ -49,10 +50,13 @@ func (f *file) readLine() (s string, ok bool) {
 	}
 	if len(f.data) < cap(f.data) {
 		ln := len(f.data)
-		n, _ := io.ReadFull(f.file, f.data[ln:cap(f.data)])
+		n, err := io.ReadFull(f.file, f.data[ln:cap(f.data)])
 		if n >= 0 {
 			f.data = f.data[0 : ln+n]
 		}
+		if err == os.EOF {
+			f.atEOF = true
+		}
 	}
 	s, ok = f.getLineFromData()
 	return
@@ -63,7 +67,7 @@ func open(name string) (*file, os.Error) {
 	if err != nil {
 		return nil, err
 	}
-	return &file{fd, make([]byte, 1024)[0:0]}, nil
+	return &file{fd, make([]byte, 1024)[0:0], false}, nil
 }
 
 func byteIndex(s string, c byte) int {