archive/zip: replace Writer.Comment field with SetComment method

A method is more in keeping with the rest of the Writer API and
incidentally allows the comment error to be reported earlier.

Fixes #22737.

Change-Id: I1eee2103a0720c76d0c394ccd6541e6219996dc0
Reviewed-on: https://go-review.googlesource.com/79415
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>

diff --git a/src/archive/zip/writer.go b/src/archive/zip/writer.go
index ebb2a2edd08626dd83630395c9fd9e9fa96daa67..bcab212d4054990c3e4ebfaabc8e08efd7f44606 100644 (file)
--- a/src/archive/zip/writer.go
+++ b/src/archive/zip/writer.go
@@ -26,13 +26,11 @@ type Writer struct {
        last        *fileWriter
        closed      bool
        compressors map[uint16]Compressor
+       comment     string
 
        // testHookCloseSizeOffset if non-nil is called with the size
        // of offset of the central directory at Close.
        testHookCloseSizeOffset func(size, offset uint64)
-
-       // Comment is the central directory comment and must be set before Close is called.
-       Comment string
 }
 
 type header struct {
@@ -62,13 +60,19 @@ func (w *Writer) Flush() error {
        return w.cw.w.(*bufio.Writer).Flush()
 }
 
-// Close finishes writing the zip file by writing the central directory.
-// It does not (and cannot) close the underlying writer.
-func (w *Writer) Close() error {
-       if len(w.Comment) > uint16max {
+// SetComment sets the end-of-central-directory comment field.
+// It can only be called before Close.
+func (w *Writer) SetComment(comment string) error {
+       if len(comment) > uint16max {
                return errors.New("zip: Writer.Comment too long")
        }
+       w.comment = comment
+       return nil
+}
 
+// Close finishes writing the zip file by writing the central directory.
+// It does not (and cannot) close the underlying writer.
+func (w *Writer) Close() error {
        if w.last != nil && !w.last.closed {
                if err := w.last.close(); err != nil {
                        return err
@@ -189,11 +193,11 @@ func (w *Writer) Close() error {
        b.uint16(uint16(records))        // number of entries total
        b.uint32(uint32(size))           // size of directory
        b.uint32(uint32(offset))         // start of directory
-       b.uint16(uint16(len(w.Comment))) // byte size of EOCD comment
+       b.uint16(uint16(len(w.comment))) // byte size of EOCD comment
        if _, err := w.cw.Write(buf[:]); err != nil {
                return err
        }
-       if _, err := io.WriteString(w.cw, w.Comment); err != nil {
+       if _, err := io.WriteString(w.cw, w.comment); err != nil {
                return err
        }
 

diff --git a/src/archive/zip/writer_test.go b/src/archive/zip/writer_test.go
index f217a42e74f1cc03667dce1f1ae0b6a3bf02f874..28824d88eeb0bfa19394ef2f624c061909e7f2da 100644 (file)
--- a/src/archive/zip/writer_test.go
+++ b/src/archive/zip/writer_test.go
@@ -106,7 +106,16 @@ func TestWriterComment(t *testing.T) {
                // write a zip file
                buf := new(bytes.Buffer)
                w := NewWriter(buf)
-               w.Comment = test.comment
+               if err := w.SetComment(test.comment); err != nil {
+                       if test.ok {
+                               t.Fatalf("SetComment: unexpected error %v", err)
+                       }
+                       continue
+               } else {
+                       if !test.ok {
+                               t.Fatalf("SetComment: unexpected success, want error")
+                       }
+               }
 
                if err := w.Close(); test.ok == (err != nil) {
                        t.Fatal(err)