proxmox-backup/proxmox-protocol/src/chunk_stream.rs
Wolfgang Bumiller ac4e349b5e import proxmox-protocol crate
This is supposed to contain only the parts necessary to
communicate with the server via the proxmox backup protocol.
(Including the chunker, which is currently `include!()`d
from the main crate.

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
2019-03-06 10:26:10 +01:00

119 lines
2.9 KiB
Rust

use std::io::Read;
use failure::Error;
use crate::Chunker;
pub struct ChunkStream<T: Read> {
input: T,
buffer: Vec<u8>,
fill: usize,
pos: usize,
keep: bool,
eof: bool,
chunker: Chunker,
}
impl<T: Read> ChunkStream<T> {
pub fn new(input: T) -> Self {
Self {
input,
buffer: Vec::new(),
fill: 0,
pos: 0,
keep: false,
eof: false,
chunker: Chunker::new(4 * 1024 * 1024),
}
}
pub fn stream(&mut self) -> &mut Self {
self
}
fn fill_buf(&mut self) -> Result<bool, Error> {
if self.fill == self.buffer.len() {
let mut more = self.buffer.len(); // just double it
if more == 0 {
more = 1024 * 1024; // at the start, make a 1M buffer
}
// we need more data:
self.buffer.reserve(more);
unsafe {
self.buffer.set_len(self.buffer.capacity());
}
}
match self.input.read(&mut self.buffer[self.fill..]) {
Ok(more) => {
if more == 0 {
self.eof = true;
}
self.fill += more;
Ok(true)
}
Err(err) => {
if err.kind() == std::io::ErrorKind::WouldBlock {
Ok(false)
} else {
Err(err.into())
}
}
}
}
fn consume(&mut self) {
assert!(self.fill >= self.pos);
let remaining = self.fill - self.pos;
unsafe {
std::ptr::copy_nonoverlapping(
&self.buffer[self.pos] as *const u8,
self.buffer.as_mut_ptr(),
remaining,
);
}
self.fill = remaining;
self.pos = 0;
}
pub fn next(&mut self) {
self.keep = false;
}
// This crate should not depend on the futures create, so we use another Option instead of
// Async<T>.
pub fn get(&mut self) -> Result<Option<Option<&[u8]>>, Error> {
if self.keep {
return Ok(Some(Some(&self.buffer[0..self.pos])));
}
if self.eof {
return Ok(Some(None));
}
if self.pos != 0 {
self.consume();
}
loop {
match self.fill_buf() {
Ok(true) => (),
Ok(false) => return Ok(None),
Err(err) => return Err(err),
}
// Note that if we hit EOF we hit a hard boundary...
let boundary = self.chunker.scan(&self.buffer[self.pos..self.fill]);
if boundary == 0 && !self.eof {
self.pos = self.fill;
continue;
}
self.pos += boundary;
self.keep = true;
return Ok(Some(Some(&self.buffer[0..self.pos])));
}
}
}