"crypto/rand"
"errors"
"fmt"
+ "io"
prand "math/rand"
"os"
+ "path"
+ "strings"
"sync/atomic"
"time"
// webdavFS implements a webdav.FileSystem by wrapping an
// arvados.CollectionFilesystem.
+//
+// Collections don't preserve empty directories, so Mkdir is
+// effectively a no-op, and we need to make parent dirs spring into
+// existence automatically so sequences like "mkcol foo; put foo/bar"
+// work as expected.
type webdavFS struct {
- collfs arvados.CollectionFileSystem
- update func() error
+ collfs arvados.CollectionFileSystem
+ writing bool
+ // webdav PROPFIND reads the first few bytes of each file
+ // whose filename extension isn't recognized, which is
+ // prohibitively expensive: we end up fetching multiple 64MiB
+ // blocks. Avoid this by returning EOF on all reads when
+ // handling a PROPFIND.
+ alwaysReadEOF bool
+}
+
+func (fs *webdavFS) makeparents(name string) {
+ dir, _ := path.Split(name)
+ if dir == "" || dir == "/" {
+ return
+ }
+ dir = dir[:len(dir)-1]
+ fs.makeparents(dir)
+ fs.collfs.Mkdir(dir, 0755)
}
func (fs *webdavFS) Mkdir(ctx context.Context, name string, perm os.FileMode) error {
+ if !fs.writing {
+ return errReadOnly
+ }
+ name = strings.TrimRight(name, "/")
+ fs.makeparents(name)
return fs.collfs.Mkdir(name, 0755)
}
func (fs *webdavFS) OpenFile(ctx context.Context, name string, flag int, perm os.FileMode) (f webdav.File, err error) {
writing := flag&(os.O_WRONLY|os.O_RDWR) != 0
- if writing && fs.update == nil {
- return nil, errReadOnly
+ if writing {
+ fs.makeparents(name)
}
f, err = fs.collfs.OpenFile(name, flag, perm)
- if writing && err == nil {
- f = writingFile{File: f, update: fs.update}
+ if !fs.writing {
+ // webdav module returns 404 on all OpenFile errors,
+ // but returns 405 Method Not Allowed if OpenFile()
+ // succeeds but Write() or Close() fails. We'd rather
+ // have 405.
+ f = writeFailer{File: f, err: errReadOnly}
+ }
+ if fs.alwaysReadEOF {
+ f = readEOF{File: f}
}
return
}
func (fs *webdavFS) RemoveAll(ctx context.Context, name string) error {
- return errReadOnly
+ return fs.collfs.RemoveAll(name)
}
func (fs *webdavFS) Rename(ctx context.Context, oldName, newName string) error {
- return errReadOnly
+ if !fs.writing {
+ return errReadOnly
+ }
+ fs.makeparents(newName)
+ return fs.collfs.Rename(oldName, newName)
}
func (fs *webdavFS) Stat(ctx context.Context, name string) (os.FileInfo, error) {
+ if fs.writing {
+ fs.makeparents(name)
+ }
return fs.collfs.Stat(name)
}
-type writingFile struct {
+type writeFailer struct {
webdav.File
- update func() error
+ err error
}
-func (f writingFile) Close() error {
- if err := f.File.Close(); err != nil || f.update == nil {
- return err
- }
- return f.update()
+func (wf writeFailer) Write([]byte) (int, error) {
+ return 0, wf.err
+}
+
+func (wf writeFailer) Close() error {
+ return wf.err
+}
+
+type readEOF struct {
+ webdav.File
+}
+
+func (readEOF) Read(p []byte) (int, error) {
+ return 0, io.EOF
}
// noLockSystem implements webdav.LockSystem by returning success for