func (md *mdRelation) NBlocks() (system.BlockNumber, error) {
relpath := system.RelPath(md.node)
fi, err := os.Stat(relpath)
if err != nil {
return 0, err
}
return system.BlockNumber(fi.Size() / int64(system.BlockSize)), nil
}
func (rel *HeapRelation) GetNumberOfBlocks() (system.BlockNumber, error) {
relpath := system.RelPath(rel.RelNode)
fi, err := os.Stat(relpath)
if err != nil {
return 0, err
}
size := fi.Size()
if size%system.BlockSize != 0 {
return 0, fmt.Errorf("size of %s = %d is not module BlockSize", size, relpath)
}
return system.BlockNumber(size / system.BlockSize), nil
}
func (md *mdRelation) openFile() error {
// TODO: do we care concurrency?
if md.file == nil {
relpath := system.RelPath(md.node)
file, err := os.OpenFile(relpath, os.O_RDWR, 0600)
if err != nil {
md.file = nil
return err
}
md.file = file
}
return nil
}