client/catar_backup_stream.rs: new helper for catar uploads to server

src/client/catar_backup_stream.rs

@@ -0,0 +1,86 @@
+use failure::*;
+
+use std::thread;
+use std::os::unix::io::FromRawFd;
+
+use futures::{Async, Poll};
+use futures::stream::Stream;
+
+use nix::fcntl::OFlag;
+use nix::sys::stat::Mode;
+
+use crate::catar::encoder::*;
+
+pub struct CaTarBackupStream {
+    pipe: Option<std::fs::File>,
+    buffer: Vec<u8>,
+    child: Option<thread::JoinHandle<()>>,
+}
+
+impl Drop for CaTarBackupStream {
+
+    fn drop(&mut self) {
+        drop(self.pipe.take());
+        self.child.take().unwrap().join().unwrap();
+    }
+}
+
+impl CaTarBackupStream {
+
+    pub fn new(dirname: &str) -> Result<Self, Error> {
+        let mut buffer = Vec::with_capacity(4096);
+        unsafe { buffer.set_len(buffer.capacity()); }
+
+        let (rx, tx) = nix::unistd::pipe()?;
+
+        let mut dir = nix::dir::Dir::open(dirname, OFlag::O_DIRECTORY, Mode::empty())?;
+        let path = std::path::PathBuf::from(dirname);
+
+        let child = thread::spawn(move|| {
+            let mut writer = unsafe { std::fs::File::from_raw_fd(tx) };
+            if let Err(err) = CaTarEncoder::encode(path, &mut dir, None, &mut writer) {
+                eprintln!("catar encode failed - {}", err);
+            }
+        });
+
+        let pipe = unsafe { std::fs::File::from_raw_fd(rx) };
+
+        Ok(Self { pipe: Some(pipe), buffer, child: Some(child) })
+    }
+}
+
+impl Stream for CaTarBackupStream {
+
+    type Item = Vec<u8>;
+    type Error = Error;
+
+    // Note: This is not async!!
+
+    fn poll(&mut self) -> Poll<Option<Vec<u8>>, Error> {
+
+        use std::io::Read;
+
+         loop {
+            let pipe = match self.pipe {
+                Some(ref mut pipe) => pipe,
+                None => unreachable!(),
+            };
+            match pipe.read(&mut self.buffer) {
+                Ok(n) => {
+                    if n == 0 {
+                        return Ok(Async::Ready(None))
+                    } else {
+                        let data = self.buffer[..n].to_vec();
+                        return Ok(Async::Ready(Some(data)))
+                    }
+                }
+                Err(ref e) if e.kind() == std::io::ErrorKind::Interrupted => {
+                    // try again
+                }
+                Err(err) => {
+                    return Err(err.into())
+                }
+            };
+        }
+    }
+}

src/lib.rs

@@ -56,3 +56,8 @@ pub mod cli {
 
 
 pub mod api3;
+
+pub mod client {
+
+    pub mod catar_backup_stream;
+}