refactor webdav subdirectory, fixes #4967 (#4969)

* refactor webdav subdirectory, fixes #4967

* fix bug where Name() was not called on delegate wrappedFileInfo

weed/server/wrapped_webdav_fs.go

@@ -0,0 +1,97 @@
+package weed_server
+
+import (
+	"context"
+	"golang.org/x/net/webdav"
+	"io/fs"
+	"os"
+	"strings"
+)
+
+type wrappedFs struct {
+	subFolder string
+	webdav.FileSystem
+}
+
+// NewWrappedFs returns a webdav.FileSystem identical to fs, except it
+// provides access to a sub-folder of fs that is denominated by subFolder.
+// It transparently handles renaming paths and filenames so that the outer part of the wrapped filesystem
+// does not leak out.
+func NewWrappedFs(fs webdav.FileSystem, subFolder string) webdav.FileSystem {
+	return wrappedFs{
+		subFolder:  subFolder,
+		FileSystem: fs,
+	}
+}
+
+func (w wrappedFs) Mkdir(ctx context.Context, name string, perm os.FileMode) error {
+	name = w.subFolder + name
+	return w.FileSystem.Mkdir(ctx, name, perm)
+}
+
+func (w wrappedFs) OpenFile(ctx context.Context, name string, flag int, perm os.FileMode) (webdav.File, error) {
+	name = w.subFolder + name
+	file, err := w.FileSystem.OpenFile(ctx, name, flag, perm)
+	file = wrappedFile{
+		File:      file,
+		subFolder: &w.subFolder,
+	}
+
+	return file, err
+}
+
+func (w wrappedFs) RemoveAll(ctx context.Context, name string) error {
+	name = w.subFolder + name
+	return w.FileSystem.RemoveAll(ctx, name)
+}
+
+func (w wrappedFs) Rename(ctx context.Context, oldName, newName string) error {
+	oldName = w.subFolder + oldName
+	newName = w.subFolder + newName
+	return w.FileSystem.Rename(ctx, oldName, newName)
+}
+
+func (w wrappedFs) Stat(ctx context.Context, name string) (os.FileInfo, error) {
+	name = w.subFolder + name
+	info, err := w.FileSystem.Stat(ctx, name)
+	info = wrappedFileInfo{
+		subFolder: &w.subFolder,
+		FileInfo:  info,
+	}
+	return info, err
+}
+
+type wrappedFile struct {
+	webdav.File
+	subFolder *string
+}
+
+func (w wrappedFile) Readdir(count int) ([]fs.FileInfo, error) {
+	infos, err := w.File.Readdir(count)
+	for i, info := range infos {
+		infos[i] = wrappedFileInfo{
+			subFolder: w.subFolder,
+			FileInfo:  info,
+		}
+	}
+	return infos, err
+}
+
+func (w wrappedFile) Stat() (fs.FileInfo, error) {
+	info, err := w.File.Stat()
+	info = wrappedFileInfo{
+		subFolder: w.subFolder,
+		FileInfo:  info,
+	}
+	return info, err
+}
+
+type wrappedFileInfo struct {
+	subFolder *string
+	fs.FileInfo
+}
+
+func (w wrappedFileInfo) Name() string {
+	name := w.FileInfo.Name()
+	return strings.TrimPrefix(name, *w.subFolder)
+}