func (backend *BlobsFileBackend) Delete(hash string) error {
if !backend.loaded {
panic("backend BlobsFileBackend not loaded")
}
if backend.writeOnly {
return nil
//panic("backend is in write-only mode")
}
blobPos, err := backend.index.GetPos(hash)
if err != nil {
return fmt.Errorf("Error fetching GetPos: %v", err)
}
if blobPos == nil {
return fmt.Errorf("Blob %v not found in index", err)
}
var f *os.File
// check if the file is already open for writing
if blobPos.n == backend.n {
f = backend.current
} else {
f, err = os.OpenFile(backend.filename(blobPos.n), os.O_RDWR, 0666)
if err != nil {
return fmt.Errorf("failed to open blobsfile %v", backend.filename(blobPos.n), err)
}
defer f.Close()
}
// Add Deleted to the flag
if _, err := f.WriteAt([]byte{Deleted}, int64(blobPos.offset+hashSize)); err != nil {
return err
}
// Delete the index entry
if err := backend.index.DeletePos(hash); err != nil {
return err
}
// Punch a hole in the file if possible
if err := fileutil.PunchHole(f, int64(blobPos.offset+Overhead), int64(blobPos.size)); err != nil {
return fmt.Errorf("failed to punch hole: %v", err)
}
return nil
}
// PunchHole implements Filer.
func (f *SimpleFileFiler) PunchHole(off, size int64) (err error) {
return fileutil.PunchHole(f.file, off, size)
}