Revive xz support

go.mod

@@ -14,4 +14,5 @@ require (
 require (
 	github.com/dlclark/regexp2 v1.10.0 // indirect
 	github.com/stretchr/testify v1.7.0 // indirect
+	github.com/ulikunitz/xz v0.5.11 // indirect
 )

go.sum

@@ -20,6 +20,8 @@ github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/ulikunitz/xz v0.5.11 h1:kpFauv27b6ynzBNT/Xy+1k+fK4WswhN/6PN5WhFAGw8=
+github.com/ulikunitz/xz v0.5.11/go.mod h1:nbz6k7qbPmH4IRqmfOplQw/tblSgqTqBwxkY0oWt/14=
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=

m/zopen.go

@@ -6,6 +6,8 @@ import (
 	"io"
 	"os"
 	"strings"
+
+	"github.com/ulikunitz/xz"
 )
 
 func ZOpen(filename string) (io.ReadCloser, error) {
@@ -23,6 +25,17 @@ func ZOpen(filename string) (io.ReadCloser, error) {
 			io.Reader
 			io.Closer
 		}{bzip2.NewReader(file), file}, nil
+
+	case strings.HasSuffix(filename, ".xz"):
+		xzReader, err := xz.NewReader(file)
+		if err != nil {
+			return nil, err
+		}
+
+		return struct {
+			io.Reader
+			io.Closer
+		}{xzReader, file}, nil
 	}
 
 	return file, nil