new file mode 100644

@@ -0,0 +1,127 @@

+package archive

+

+import (

+	"archive/tar"

+	"fmt"

+	"io"

+	"io/ioutil"

+	"os"

+	"path"

+	"sort"

+	"testing"

+)

+

+func TestHardLinkOrder(t *testing.T) {

+	names := []string{"file1.txt", "file2.txt", "file3.txt"}

+	msg := []byte("Hey y'all")

+

+	// Create dir

+	src, err := ioutil.TempDir("", "docker-hardlink-test-src-")

+	if err != nil {

+		t.Fatal(err)

+	}

+	//defer os.RemoveAll(src)

+	for _, name := range names {

+		func() {

+			fh, err := os.Create(path.Join(src, name))

+			if err != nil {

+				t.Fatal(err)

+			}

+			defer fh.Close()

+			if _, err = fh.Write(msg); err != nil {

+				t.Fatal(err)

+			}

+		}()

+	}

+	// Create dest, with changes that includes hardlinks

+	dest, err := ioutil.TempDir("", "docker-hardlink-test-dest-")

+	if err != nil {

+		t.Fatal(err)

+	}

+	os.RemoveAll(dest) // we just want the name, at first

+	if err := copyDir(src, dest); err != nil {

+		t.Fatal(err)

+	}

+	defer os.RemoveAll(dest)

+	for _, name := range names {

+		for i := 0; i < 5; i++ {

+			if err := os.Link(path.Join(dest, name), path.Join(dest, fmt.Sprintf("%s.link%d", name, i))); err != nil {

+				t.Fatal(err)

+			}

+		}

+	}

+

+	// get changes

+	changes, err := ChangesDirs(dest, src)

+	if err != nil {

+		t.Fatal(err)

+	}

+

+	// sort

+	sort.Sort(changesByPath(changes))

+

+	// ExportChanges

+	ar, err := ExportChanges(dest, changes)

+	if err != nil {

+		t.Fatal(err)

+	}

+	hdrs, err := walkHeaders(ar)

+	if err != nil {

+		t.Fatal(err)

+	}

+

+	// reverse sort

+	sort.Sort(sort.Reverse(changesByPath(changes)))

+	// ExportChanges

+	arRev, err := ExportChanges(dest, changes)

+	if err != nil {

+		t.Fatal(err)

+	}

+	hdrsRev, err := walkHeaders(arRev)

+	if err != nil {

+		t.Fatal(err)

+	}

+

+	// line up the two sets

+	sort.Sort(tarHeaders(hdrs))

+	sort.Sort(tarHeaders(hdrsRev))

+

+	// compare Size and LinkName

+	for i := range hdrs {

+		if hdrs[i].Name != hdrsRev[i].Name {

+			t.Errorf("headers - expected name %q; but got %q", hdrs[i].Name, hdrsRev[i].Name)

+		}

+		if hdrs[i].Size != hdrsRev[i].Size {

+			t.Errorf("headers - %q expected size %d; but got %d", hdrs[i].Name, hdrs[i].Size, hdrsRev[i].Size)

+		}

+		if hdrs[i].Typeflag != hdrsRev[i].Typeflag {

+			t.Errorf("headers - %q expected type %d; but got %d", hdrs[i].Name, hdrs[i].Typeflag, hdrsRev[i].Typeflag)

+		}

+		if hdrs[i].Linkname != hdrsRev[i].Linkname {

+			t.Errorf("headers - %q expected linkname %q; but got %q", hdrs[i].Name, hdrs[i].Linkname, hdrsRev[i].Linkname)

+		}

+	}

+

+}

+

+type tarHeaders []tar.Header

+

+func (th tarHeaders) Len() int           { return len(th) }

+func (th tarHeaders) Swap(i, j int)      { th[j], th[i] = th[i], th[j] }

+func (th tarHeaders) Less(i, j int) bool { return th[i].Name < th[j].Name }

+

+func walkHeaders(r io.Reader) ([]tar.Header, error) {

+	t := tar.NewReader(r)

+	headers := []tar.Header{}

+	for {

+		hdr, err := t.Next()

+		if err != nil {

+			if err == io.EOF {

+				break

+			}

+			return headers, err

+		}

+		headers = append(headers, *hdr)

+	}

+	return headers, nil

+}