restic/internal/webdav/file.go
2024-02-25 11:01:59 +01:00

106 lines
2.3 KiB
Go

package webdav
import (
"context"
"io"
"os"
"github.com/anacrolix/fuse"
"github.com/anacrolix/fuse/fs"
"github.com/restic/restic/internal/debug"
"golang.org/x/net/webdav"
)
type fuseFile interface {
fs.Node
fs.NodeOpener
}
// RepoFile implements a read-only file
type RepoFile struct {
name string
file fuseFile
handle fs.HandleReader
seek int64
size int64
ctx context.Context
}
// statically ensure that RepoFile implements webdav.File
var _ webdav.File = &RepoFile{}
func (f *RepoFile) Write(p []byte) (int, error) {
return 0, webdav.ErrForbidden
}
// Close closes the repo file.
func (f *RepoFile) Close() error {
debug.Log("Close %v", f.name)
return nil
}
// Read reads up to len(p) byte from the file.
func (f *RepoFile) Read(p []byte) (int, error) {
debug.Log("Read %v, count %d", f.name, len(p))
var err error
if f.handle == nil {
h, err := f.file.Open(f.ctx, nil, nil)
if err != nil {
return 0, err
}
f.handle = h.(fs.HandleReader)
}
maxread := int(f.size - f.seek)
if len(p) < maxread {
maxread = len(p)
}
if maxread <= 0 {
return 0, io.EOF
}
req := &fuse.ReadRequest{Size: maxread, Offset: f.seek}
resp := &fuse.ReadResponse{Data: p}
err = f.handle.Read(f.ctx, req, resp)
if err != nil {
return 0, err
}
f.seek += int64(len(resp.Data))
return len(resp.Data), nil
}
// Seek sets the offset for the next Read or Write to offset, interpreted
// according to whence: SeekStart means relative to the start of the file,
// SeekCurrent means relative to the current offset, and SeekEnd means relative
// to the end. Seek returns the new offset relative to the start of the file
// and an error, if any.
func (f *RepoFile) Seek(offset int64, whence int) (int64, error) {
debug.Log("Seek %v, offset: %d", f.name, offset)
switch whence {
case os.SEEK_SET:
f.seek = offset
case os.SEEK_CUR:
f.seek += offset
case os.SEEK_END:
f.seek = f.size + offset
}
if f.seek < 0 || f.seek > f.size {
return 0, io.EOF
}
return f.seek, nil
}
func (f *RepoFile) Readdir(count int) ([]os.FileInfo, error) {
return nil, io.EOF
}
// Stat returns a FileInfo describing the named file.
func (f *RepoFile) Stat() (os.FileInfo, error) {
debug.Log("Stat %v", f.name)
var attr fuse.Attr
f.file.Attr(f.ctx, &attr)
return fileInfoFromAttr(f.name, attr), nil
}