diskio.File: Add .Close() and don't have .Size() return an error

3 files changed, 55 insertions, 13 deletions

diff --git a/lib/diskio/file_iface.go b/lib/diskio/file_iface.go
new file mode 100644
index 0000000..206db0c
--- /dev/null
+++ b/lib/diskio/file_iface.go
@@ -0,0 +1,24 @@
+// Copyright (C) 2022  Luke Shumaker <lukeshu@lukeshu.com>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+package diskio
+
+import (
+	"io"
+)
+
+type File[A ~int64] interface {
+	Name() string
+	Size() A
+	Close() error
+	ReadAt(p []byte, off A) (n int, err error)
+	WriteAt(p []byte, off A) (n int, err error)
+}
+
+type assertAddr int64
+
+var (
+	_ io.WriterAt = File[int64](nil)
+	_ io.ReaderAt = File[int64](nil)
+)
diff --git a/lib/diskio/file_os.go b/lib/diskio/file_os.go
new file mode 100644
index 0000000..2fa521d
--- /dev/null
+++ b/lib/diskio/file_os.go
@@ -0,0 +1,31 @@
+// Copyright (C) 2022  Luke Shumaker <lukeshu@lukeshu.com>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+package diskio
+
+import (
+	"os"
+)
+
+type OSFile[A ~int64] struct {
+	*os.File
+}
+
+var _ File[assertAddr] = (*OSFile[assertAddr])(nil)
+
+func (f *OSFile[A]) Size() A {
+	fi, err := f.Stat()
+	if err != nil {
+		return 0
+	}
+	return A(fi.Size())
+}
+
+func (f *OSFile[A]) ReadAt(dat []byte, paddr A) (int, error) {
+	return f.File.ReadAt(dat, int64(paddr))
+}
+
+func (f *OSFile[A]) WriteAt(dat []byte, paddr A) (int, error) {
+	return f.File.WriteAt(dat, int64(paddr))
+}
diff --git a/lib/diskio/ref.go b/lib/diskio/ref.go
index 9782743..137701d 100644
--- a/lib/diskio/ref.go
+++ b/lib/diskio/ref.go
@@ -6,23 +6,10 @@ package diskio
 
 import (
 	"fmt"
-	"io"
 
 	"git.lukeshu.com/btrfs-progs-ng/lib/binstruct"
 )
 
-type File[A ~int64] interface {
-	Name() string
-	Size() (A, error)
-	ReadAt(p []byte, off A) (n int, err error)
-	WriteAt(p []byte, off A) (n int, err error)
-}
-
-var (
-	_ io.WriterAt = File[int64](nil)
-	_ io.ReaderAt = File[int64](nil)
-)
-
 type Ref[A ~int64, T any] struct {
 	File File[A]
 	Addr A