add open/close utility functions

2 files changed, 37 insertions, 0 deletions

diff --git a/pkg/btrfs/io2_fs.go b/pkg/btrfs/io2_fs.go
index dcf7df8..740e6e6 100644
--- a/pkg/btrfs/io2_fs.go
+++ b/pkg/btrfs/io2_fs.go
@@ -2,6 +2,7 @@ package btrfs
 
 import (
 	"fmt"
+	"io"
 
 	"lukeshu.com/btrfs-tools/pkg/btrfs/btrfsitem"
 	"lukeshu.com/btrfs-tools/pkg/btrfs/btrfsvol"
@@ -166,3 +167,15 @@ func (fs *FS) initDev(sb *util.Ref[PhysicalAddr, Superblock]) error {
 	}
 	return nil
 }
+
+func (fs *FS) Close() error {
+	var err error
+	for _, dev := range fs.LV.PhysicalVolumes() {
+		if _err := dev.Close(); _err != nil && err == nil {
+			err = _err
+		}
+	}
+	return err
+}
+
+var _ io.Closer = (*FS)(nil)
diff --git a/pkg/btrfsmisc/open.go b/pkg/btrfsmisc/open.go
new file mode 100644
index 0000000..bf72670
--- /dev/null
+++ b/pkg/btrfsmisc/open.go
@@ -0,0 +1,24 @@
+package btrfsmisc
+
+import (
+	"fmt"
+	"os"
+
+	"lukeshu.com/btrfs-tools/pkg/btrfs"
+)
+
+func Open(flag int, filenames ...string) (*btrfs.FS, error) {
+	fs := new(btrfs.FS)
+	for _, filename := range filenames {
+		fh, err := os.OpenFile(filename, flag, 0)
+		if err != nil {
+			_ = fs.Close()
+			return nil, fmt.Errorf("file %q: %w", filename, err)
+		}
+		if err := fs.AddDevice(&btrfs.Device{File: fh}); err != nil {
+			_ = fs.Close()
+			return nil, fmt.Errorf("file %q: %w", filename, err)
+		}
+	}
+	return fs, nil
+}