From ea595359c578b22bbea013cfc798d776a83109d3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B8rn=20Erik=20Pedersen?=
 <bjorn.erik.pedersen@gmail.com>
Date: Fri, 15 Jul 2022 12:27:01 +0200
Subject: [PATCH] Make mem.File implement fs.ReadDirFile

---
 internal/common/adapters.go | 27 +++++++++++++++++++++++++++
 iofs.go                     | 17 ++++-------------
 iofs_test.go                |  6 ++++--
 mem/file.go                 | 18 ++++++++++++++++++
 4 files changed, 53 insertions(+), 15 deletions(-)
 create mode 100644 internal/common/adapters.go

diff --git a/internal/common/adapters.go b/internal/common/adapters.go
new file mode 100644
index 00000000..60685caa
--- /dev/null
+++ b/internal/common/adapters.go
@@ -0,0 +1,27 @@
+// Copyright © 2022 Steve Francia <spf@spf13.com>.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package common
+
+import "io/fs"
+
+// FileInfoDirEntry provides an adapter from os.FileInfo to fs.DirEntry
+type FileInfoDirEntry struct {
+	fs.FileInfo
+}
+
+var _ fs.DirEntry = FileInfoDirEntry{}
+
+func (d FileInfoDirEntry) Type() fs.FileMode { return d.FileInfo.Mode().Type() }
+
+func (d FileInfoDirEntry) Info() (fs.FileInfo, error) { return d.FileInfo, nil }
diff --git a/iofs.go b/iofs.go
index 8bc97354..0ba1d4c1 100644
--- a/iofs.go
+++ b/iofs.go
@@ -10,6 +10,8 @@ import (
 	"path"
 	"sort"
 	"time"
+
+	"github.com/spf13/afero/internal/common"
 )
 
 // IOFS adopts afero.Fs to stdlib io/fs.FS
@@ -87,7 +89,7 @@ func (iofs IOFS) ReadDir(name string) ([]fs.DirEntry, error) {
 
 	ret := make([]fs.DirEntry, len(items))
 	for i := range items {
-		ret[i] = dirEntry{items[i]}
+		ret[i] = common.FileInfoDirEntry{FileInfo: items[i]}
 	}
 
 	return ret, nil
@@ -122,17 +124,6 @@ func (IOFS) wrapError(op, path string, err error) error {
 	}
 }
 
-// dirEntry provides adapter from os.FileInfo to fs.DirEntry
-type dirEntry struct {
-	fs.FileInfo
-}
-
-var _ fs.DirEntry = dirEntry{}
-
-func (d dirEntry) Type() fs.FileMode { return d.FileInfo.Mode().Type() }
-
-func (d dirEntry) Info() (fs.FileInfo, error) { return d.FileInfo, nil }
-
 // readDirFile provides adapter from afero.File to fs.ReadDirFile needed for correct Open
 type readDirFile struct {
 	File
@@ -148,7 +139,7 @@ func (r readDirFile) ReadDir(n int) ([]fs.DirEntry, error) {
 
 	ret := make([]fs.DirEntry, len(items))
 	for i := range items {
-		ret[i] = dirEntry{items[i]}
+		ret[i] = common.FileInfoDirEntry{FileInfo: items[i]}
 	}
 
 	return ret, nil
diff --git a/iofs_test.go b/iofs_test.go
index 32f0d9d8..279c0143 100644
--- a/iofs_test.go
+++ b/iofs_test.go
@@ -15,6 +15,8 @@ import (
 	"testing"
 	"testing/fstest"
 	"time"
+
+	"github.com/spf13/afero/internal/common"
 )
 
 func TestIOFS(t *testing.T) {
@@ -94,7 +96,7 @@ func TestIOFSNativeDirEntryWhenPossible(t *testing.T) {
 			t.Fatalf("expected 2, got %d", len(entries))
 		}
 		for _, entry := range entries {
-			if _, ok := entry.(dirEntry); ok {
+			if _, ok := entry.(common.FileInfoDirEntry); ok {
 				t.Fatal("DirEntry not native")
 			}
 		}
@@ -118,7 +120,7 @@ func TestIOFSNativeDirEntryWhenPossible(t *testing.T) {
 			fileCount++
 		}
 
-		if _, ok := d.(dirEntry); ok {
+		if _, ok := d.(common.FileInfoDirEntry); ok {
 			t.Fatal("DirEntry not native")
 		}
 
diff --git a/mem/file.go b/mem/file.go
index 258880bf..3cf4693b 100644
--- a/mem/file.go
+++ b/mem/file.go
@@ -18,15 +18,20 @@ import (
 	"bytes"
 	"errors"
 	"io"
+	"io/fs"
 	"os"
 	"path/filepath"
 	"sync"
 	"sync/atomic"
 	"time"
+
+	"github.com/spf13/afero/internal/common"
 )
 
 const FilePathSeparator = string(filepath.Separator)
 
+var _ fs.ReadDirFile = &File{}
+
 type File struct {
 	// atomic requires 64-bit alignment for struct field access
 	at           int64
@@ -183,6 +188,19 @@ func (f *File) Readdirnames(n int) (names []string, err error) {
 	return names, err
 }
 
+// Implements fs.ReadDirFile
+func (f *File) ReadDir(n int) ([]fs.DirEntry, error) {
+	fi, err := f.Readdir(n)
+	if err != nil {
+		return nil, err
+	}
+	di := make([]fs.DirEntry, len(fi))
+	for i, f := range fi {
+		di[i] = common.FileInfoDirEntry{FileInfo: f}
+	}
+	return di, nil
+}
+
 func (f *File) Read(b []byte) (n int, err error) {
 	f.fileData.Lock()
 	defer f.fileData.Unlock()