archive/zip: read and write unix file modes

R=golang-dev, rsc, adg
CC=golang-dev
https://golang.org/cl/5124044

src/pkg/archive/zip/reader.go

@@ -238,7 +238,7 @@ func readDirectoryHeader(f *File, r io.Reader) os.Error {
 	commentLen := int(c.Uint16(b[32:34]))
 	// startDiskNumber := c.Uint16(b[34:36])    // Unused
 	// internalAttributes := c.Uint16(b[36:38]) // Unused
-	// externalAttributes := c.Uint32(b[38:42]) // Unused
+	f.ExternalAttrs = c.Uint32(b[38:42])
 	f.headerOffset = int64(c.Uint32(b[42:46]))
 	d := make([]byte, filenameLen+extraLen+commentLen)
 	if _, err := io.ReadFull(r, d); err != nil {

src/pkg/archive/zip/reader_test.go

@@ -26,6 +26,7 @@ type ZipTestFile struct {
 	Content []byte // if blank, will attempt to compare against File
 	File    string // name of file to compare to (relative to testdata/)
 	Mtime   string // modified time in format "mm-dd-yy hh:mm:ss"
+	Mode    uint32
 }
 
 // Caution: The Mtime values found for the test files should correspond to
@@ -47,11 +48,13 @@ var tests = []ZipTest{
 				Name:    "test.txt",
 				Content: []byte("This is a test text file.\n"),
 				Mtime:   "09-05-10 12:12:02",
+				Mode:    0x81a4,
 			},
 			{
 				Name:  "gophercolor16x16.png",
 				File:  "gophercolor16x16.png",
 				Mtime: "09-05-10 15:52:58",
+				Mode:  0x81a4,
 			},
 		},
 	},
@@ -162,6 +165,8 @@ func readTestFile(t *testing.T, ft ZipTestFile, f *File) {
 		t.Errorf("%s: mtime=%s (%d); want %s (%d)", f.Name, time.SecondsToUTC(got), got, mtime, want)
 	}
 
+	testFileMode(t, f, ft.Mode)
+
 	size0 := f.UncompressedSize
 
 	var b bytes.Buffer
@@ -203,6 +208,19 @@ func readTestFile(t *testing.T, ft ZipTestFile, f *File) {
 	}
 }
 
+func testFileMode(t *testing.T, f *File, want uint32) {
+	mode, err := f.Mode()
+	if want == 0 {
+		if err == nil {
+			t.Errorf("%s mode: got %v, want none", f.Name, mode)
+		}
+	} else if err != nil {
+		t.Errorf("%s mode: %s", f.Name, err)
+	} else if mode != want {
+		t.Errorf("%s mode: want 0x%x, got 0x%x", f.Name, want, mode)
+	}
+}
+
 func TestInvalidFiles(t *testing.T) {
 	const size = 1024 * 70 // 70kb
 	b := make([]byte, size)

src/pkg/archive/zip/struct.go

@@ -28,6 +28,9 @@ const (
 	directoryHeaderLen       = 46 // + filename + extra + comment
 	directoryEndLen          = 22 // + comment
 	dataDescriptorLen        = 12
+
+	// Constants for the first byte in CreatorVersion
+	creatorUnix = 3
 )
 
 type FileHeader struct {
@@ -42,6 +45,7 @@ type FileHeader struct {
 	CompressedSize   uint32
 	UncompressedSize uint32
 	Extra            []byte
+	ExternalAttrs    uint32 // Meaning depends on CreatorVersion
 	Comment          string
 }
 
@@ -89,3 +93,18 @@ func (h *FileHeader) Mtime_ns() int64 {
 	t := msDosTimeToTime(h.ModifiedDate, h.ModifiedTime)
 	return t.Seconds() * 1e9
 }
+
+// Mode returns the permission and mode bits for the FileHeader.
+// An error is returned in case the information is not available.
+func (h *FileHeader) Mode() (mode uint32, err os.Error) {
+	if h.CreatorVersion>>8 == creatorUnix {
+		return h.ExternalAttrs >> 16, nil
+	}
+	return 0, os.NewError("file mode not available")
+}
+
+// SetMode changes the permission and mode bits for the FileHeader.
+func (h *FileHeader) SetMode(mode uint32) {
+	h.CreatorVersion = h.CreatorVersion&0xff | creatorUnix<<8
+	h.ExternalAttrs = mode << 16
+}

src/pkg/archive/zip/writer.go

@@ -69,7 +69,7 @@ func (w *Writer) Close() (err os.Error) {
 		write(w, uint16(len(h.Comment)))
 		write(w, uint16(0)) // disk number start
 		write(w, uint16(0)) // internal file attributes
-		write(w, uint32(0)) // external file attributes
+		write(w, h.ExternalAttrs)
 		write(w, h.offset)
 		writeBytes(w, []byte(h.Name))
 		writeBytes(w, h.Extra)
@@ -115,7 +115,7 @@ func (w *Writer) CreateHeader(fh *FileHeader) (io.Writer, os.Error) {
 	}
 
 	fh.Flags |= 0x8 // we will write a data descriptor
-	fh.CreatorVersion = 0x14
+	fh.CreatorVersion = fh.CreatorVersion&0xff00 | 0x14
 	fh.ReaderVersion = 0x14
 
 	fw := &fileWriter{

src/pkg/archive/zip/writer_test.go

@@ -13,19 +13,45 @@ import (
 
 // TODO(adg): a more sophisticated test suite
 
-const testString = "Rabbits, guinea pigs, gophers, marsupial rats, and quolls."
+type WriteTest struct {
+	Name   string
+	Data   []byte
+	Method uint16
+	Mode   uint32
+}
+
+var writeTests = []WriteTest{
+	WriteTest{
+		Name:   "foo",
+		Data:   []byte("Rabbits, guinea pigs, gophers, marsupial rats, and quolls."),
+		Method: Store,
+	},
+	WriteTest{
+		Name:   "bar",
+		Data:   nil, // large data set in the test
+		Method: Deflate,
+		Mode:   0x81ed,
+	},
+}
 
 func TestWriter(t *testing.T) {
 	largeData := make([]byte, 1<<17)
 	for i := range largeData {
 		largeData[i] = byte(rand.Int())
 	}
+	writeTests[1].Data = largeData
+	defer func() {
+		writeTests[1].Data = nil
+	}()
 
 	// write a zip file
 	buf := new(bytes.Buffer)
 	w := NewWriter(buf)
-	testCreate(t, w, "foo", []byte(testString), Store)
-	testCreate(t, w, "bar", largeData, Deflate)
+
+	for _, wt := range writeTests {
+		testCreate(t, w, &wt)
+	}
+
 	if err := w.Close(); err != nil {
 		t.Fatal(err)
 	}
@@ -35,26 +61,34 @@ func TestWriter(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	testReadFile(t, r.File[0], []byte(testString))
-	testReadFile(t, r.File[1], largeData)
+	for i, wt := range writeTests {
+		testReadFile(t, r.File[i], &wt)
+	}
 }
 
-func testCreate(t *testing.T, w *Writer, name string, data []byte, method uint16) {
+func testCreate(t *testing.T, w *Writer, wt *WriteTest) {
 	header := &FileHeader{
-		Name:   name,
-		Method: method,
+		Name:   wt.Name,
+		Method: wt.Method,
+	}
+	if wt.Mode != 0 {
+		header.SetMode(wt.Mode)
 	}
 	f, err := w.CreateHeader(header)
 	if err != nil {
 		t.Fatal(err)
 	}
-	_, err = f.Write(data)
+	_, err = f.Write(wt.Data)
 	if err != nil {
 		t.Fatal(err)
 	}
 }
 
-func testReadFile(t *testing.T, f *File, data []byte) {
+func testReadFile(t *testing.T, f *File, wt *WriteTest) {
+	if f.Name != wt.Name {
+		t.Fatal("File name: got %q, want %q", f.Name, wt.Name)
+	}
+	testFileMode(t, f, wt.Mode)
 	rc, err := f.Open()
 	if err != nil {
 		t.Fatal("opening:", err)
@@ -67,7 +101,7 @@ func testReadFile(t *testing.T, f *File, data []byte) {
 	if err != nil {
 		t.Fatal("closing:", err)
 	}
-	if !bytes.Equal(b, data) {
-		t.Errorf("File contents %q, want %q", b, data)
+	if !bytes.Equal(b, wt.Data) {
+		t.Errorf("File contents %q, want %q", b, wt.Data)
 	}
 }