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use std::rc::Rc; use std::cell::RefCell; use std::io::{self, Write, ErrorKind}; pub struct RcOptionWriter<W: Write> { inner: Rc<RefCell<Option<W>>> } impl<W: Write> RcOptionWriter<W> { #[inline] pub fn new(writer: Rc<RefCell<Option<W>>>) -> RcOptionWriter<W> { RcOptionWriter { inner: writer } } } impl<W: Write> Write for RcOptionWriter<W> { #[inline] fn write(&mut self, buf: &[u8]) -> Result<usize, io::Error> { match self.inner.borrow_mut().as_mut() { Some(writer) => writer.write(buf), None => Err(io::Error::new(ErrorKind::BrokenPipe, "the writer has been removed out")) } } #[inline] fn flush(&mut self) -> Result<(), io::Error> { match self.inner.borrow_mut().as_mut() { Some(writer) => writer.flush(), None => Err(io::Error::new(ErrorKind::BrokenPipe, "the writer has been removed out")) } } }