feat: Add initialization command

pkg/operations/archive.go

@@ -33,6 +33,16 @@ func (o *Operations) Archive(
 	o.diskOperationLock.Lock()
 	defer o.diskOperationLock.Unlock()
 
+	return o.archive(getSrc, compressionLevel, overwrite, initializing)
+}
+
+func (o *Operations) archive(
+	getSrc func() (config.FileConfig, error),
+	compressionLevel string,
+	overwrite bool,
+	initializing bool,
+) ([]*tar.Header, error) {
+
 	writer, err := o.backend.GetWriter()
 	if err != nil {
 		return []*tar.Header{}, err

pkg/operations/initialize.go

@@ -0,0 +1,90 @@
+package operations
+
+import (
+	"archive/tar"
+	"io"
+	"os"
+	"os/user"
+	"path/filepath"
+	"strconv"
+	"time"
+
+	"github.com/pojntfx/stfs/pkg/config"
+)
+
+func (o *Operations) Initialize(
+	name string,
+	perm os.FileMode,
+	compressionLevel string,
+) error {
+	o.diskOperationLock.Lock()
+	defer o.diskOperationLock.Unlock()
+
+	usr, err := user.Current()
+	if err != nil {
+		return err
+	}
+
+	gid, err := strconv.Atoi(usr.Gid)
+	if err != nil {
+		// Some OSes like i.e. Windows don't support numeric GIDs, so use 0 instead
+		gid = 0
+	}
+
+	uid, err := strconv.Atoi(usr.Uid)
+	if err != nil {
+		// Some OSes like i.e. Windows don't support numeric UIDs, so use 0 instead
+		uid = 0
+	}
+
+	groups, err := usr.GroupIds()
+	if err != nil {
+		return err
+	}
+
+	gname := ""
+	if len(groups) >= 1 {
+		gname = groups[0]
+	}
+
+	typeflag := tar.TypeDir
+
+	hdr := &tar.Header{
+		Typeflag: byte(typeflag),
+
+		Name: name,
+
+		Mode:  int64(perm),
+		Uid:   uid,
+		Gid:   gid,
+		Uname: usr.Username,
+		Gname: gname,
+
+		ModTime: time.Now(),
+	}
+
+	done := false
+	if _, err := o.archive(
+		func() (config.FileConfig, error) {
+			// Exit after the first write
+			if done {
+				return config.FileConfig{}, io.EOF
+			}
+			done = true
+
+			return config.FileConfig{
+				GetFile: nil, // Not required as we never replace
+				Info:    hdr.FileInfo(),
+				Path:    filepath.ToSlash(name),
+				Link:    filepath.ToSlash(hdr.Linkname),
+			}, nil
+		},
+		compressionLevel,
+		true,
+		true,
+	); err != nil {
+		return err
+	}
+
+	return nil
+}