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#![feature(alloc, heap_api, oom)]
extern crate alloc;
extern crate byteorder;
extern crate capnp;
#[cfg(test)]
extern crate quickcheck;
mod buf;
#[cfg(test)]
mod test_utils;
use std::borrow::Borrow;
use std::collections::VecDeque;
use std::fmt;
use std::io;
use std::marker;
use std::mem;
use std::result;
use byteorder::{ByteOrder, LittleEndian};
use capnp::Word;
use capnp::message::{
Allocator,
Builder,
HeapAllocator,
Reader,
ReaderOptions,
ReaderSegments,
};
use capnp::{Error, Result};
use buf::{MutBuf, Buf};
pub struct Segments {
segments: Vec<Buf>,
}
impl ReaderSegments for Segments {
fn get_segment(&self, id: u32) -> Option<&[Word]> {
self.segments.get(id as usize).map(|buf| Word::bytes_to_words(&*buf))
}
}
pub struct MessageStream<S, A=HeapAllocator, M=Builder<A>> {
inner: S,
options: ReaderOptions,
buf: MutBuf,
buf_offset: usize,
remaining_segments: Vec<usize>,
segments: Vec<Buf>,
outbound_queue: VecDeque<M>,
current_segment_table: Vec<u8>,
write_progress: Option<(usize, usize)>,
marker_: marker::PhantomData<A>,
}
impl <S, M, A> MessageStream<S, M, A> {
pub fn new(inner: S, options: ReaderOptions) -> MessageStream<S, M, A> {
MessageStream {
inner: inner,
options: options,
buf: MutBuf::new(),
buf_offset: 0,
remaining_segments: Vec::new(),
segments: Vec::new(),
outbound_queue: VecDeque::new(),
current_segment_table: Vec::new(),
write_progress: None,
marker_: marker::PhantomData,
}
}
pub fn outbound_queue_len(&self) -> usize {
self.outbound_queue.len()
}
pub fn clear_outbound_queue(&mut self) {
if self.write_progress.is_some() {
self.outbound_queue.drain(1..);
} else {
self.outbound_queue.clear();
}
}
pub fn inner_mut(&mut self) -> &mut S {
&mut self.inner
}
pub fn inner(&self) -> &S {
&self.inner
}
}
impl <S, M, A> MessageStream<S, M, A> where S: io::Read {
fn read_segment_table(&mut self) -> Result<()> {
let MessageStream {
ref mut inner,
ref options,
ref mut buf,
ref mut buf_offset,
ref mut remaining_segments,
..
} = *self;
loop {
assert!(remaining_segments.is_empty());
match parse_segment_table(&buf[*buf_offset..], remaining_segments) {
Ok(0) => break,
Ok(n) => try!(buf.fill_or_replace(inner, buf_offset, n)),
Err(error) => return result::Result::Err(error),
}
}
*buf_offset += (remaining_segments.len() / 2 + 1) * 8;
let total_len = remaining_segments.iter()
.fold(Some(0u64), |acc, &len| {
acc.and_then(|n| n.checked_add(len as u64))
});
match total_len {
Some(len) if len <= options.traversal_limit_in_words * 8 => (),
other => return result::Result::Err(Error::new_decode_error(
"message is too large", Some(format!("{:?}", other.map(|n| n / 8))))),
}
remaining_segments.reverse();
Ok(())
}
fn read_segment(&mut self, len: usize) -> Result<Buf> {
let MessageStream {
ref mut inner,
ref mut buf,
ref mut buf_offset,
..
} = *self;
try!(buf.fill_or_replace(inner, buf_offset, len));
let buf = buf.buf(*buf_offset, len);
*buf_offset += len;
Ok(buf)
}
fn read(&mut self) -> Result<Reader<Segments>> {
if self.remaining_segments.is_empty() {
try!(self.read_segment_table());
}
while let Some(&segment_len) = self.remaining_segments.last() {
let segment = try!(self.read_segment(segment_len));
self.segments.push(segment);
self.remaining_segments.pop();
}
Ok(Reader::new(Segments { segments: mem::replace(&mut self.segments, Vec::new()) },
self.options.clone()))
}
pub fn read_message(&mut self) -> Result<Option<Reader<Segments>>> {
match self.read() {
Err(Error::Io(ref error)) if error.kind() == io::ErrorKind::WouldBlock => Ok(None),
Err(error) => Err(error),
Ok(message) => Ok(Some(message)),
}
}
}
impl <S, A, M> fmt::Debug for MessageStream<S, A, M> where S: fmt::Debug {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "MessageStream {{ inner: {:?}, outbound_messages: {} }}",
self.inner, self.outbound_queue_len())
}
}
fn serialize_segment_table(segment_table: &mut Vec<u8>, segments: &[&[Word]]) {
segment_table.clear();
let mut buf: [u8; 4] = [0; 4];
<LittleEndian as ByteOrder>::write_u32(&mut buf[..], segments.len() as u32 - 1);
segment_table.extend(&buf);
for segment in segments {
<LittleEndian as ByteOrder>::write_u32(&mut buf[..], segment.len() as u32);
segment_table.extend(&buf);
}
if segments.len() % 2 == 0 {
segment_table.extend(&[0, 0, 0, 0]);
}
}
fn write_segment<W>(write: &mut W, mut buf: &[u8], offset: &mut usize) -> io::Result<()>
where W: io::Write {
while !buf.is_empty() {
match write.write(buf) {
Ok(0) => return result::Result::Err(io::Error::new(io::ErrorKind::WriteZero,
"failed to write whole message")),
Ok(n) => { *offset += n; buf = &buf[n..] },
Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
Err(e) => return Err(e),
}
}
Ok(())
}
fn write_message<W>(write: &mut W,
segment_table: &[u8],
segments: &[&[Word]],
write_progress: &mut (usize, usize))
-> io::Result<()>
where W: io::Write {
let (ref mut segment_index, ref mut segment_offset) = *write_progress;
if *segment_index == 0 {
try!(write_segment(write, &segment_table[*segment_offset..], segment_offset));
*segment_offset = 0;
*segment_index += 1;
}
for segment in &segments[(*segment_index - 1)..] {
try!(write_segment(write,
&Word::words_to_bytes(segment)[*segment_offset..],
segment_offset));
*segment_offset = 0;
*segment_index += 1;
}
Ok(())
}
impl <S, A, M> MessageStream<S, A, M> where S: io::Write, M: Borrow<Builder<A>>, A: Allocator {
pub fn write(&mut self) -> io::Result<()> {
let MessageStream {
ref mut inner,
ref mut outbound_queue,
ref mut current_segment_table,
ref mut write_progress,
..
} = *self;
loop {
{
let message: &Builder<A> = match outbound_queue.front() {
Some(message) => message.borrow(),
None => return Ok(()),
};
*write_progress = write_progress.or_else(|| {
serialize_segment_table(current_segment_table,
&*message.get_segments_for_output());
Some((0, 0))
});
let progress: &mut (usize, usize) = write_progress.as_mut().unwrap();
let segments = &*message.get_segments_for_output();
match write_message(inner, current_segment_table, segments, progress) {
Err(ref error) if error.kind() == io::ErrorKind::WouldBlock => return Ok(()),
Ok(_) => (),
error => return error,
}
}
outbound_queue.pop_front();
*write_progress = None;
}
}
pub fn write_message(&mut self, message: M) -> io::Result<()> {
self.outbound_queue.push_back(message);
if self.outbound_queue_len() == 1 {
match self.write() {
Err(ref error) if error.kind() == io::ErrorKind::NotConnected => Ok(()),
other => other,
}
} else {
Ok(())
}
}
}
fn parse_segment_table(buf: &[u8], lengths: &mut Vec<usize>) -> Result<usize> {
if buf.len() < 8 { return Ok(8); }
let segment_count = <LittleEndian as ByteOrder>::read_u32(&buf[0..4])
.wrapping_add(1) as usize;
if segment_count >= 512 {
return result::Result::Err(Error::new_decode_error("too many segments in message",
Some(format!("{}", segment_count))));
} else if segment_count == 0 {
return result::Result::Err(Error::new_decode_error("zero segments in message", None));
}
let len = (segment_count / 2 + 1) * 8;
if buf.len() < len { return Ok(len); }
for segment in 0..segment_count {
let offset = (segment + 1) * 4;
let segment_len = <LittleEndian as ByteOrder>::read_u32(&buf[offset..]) as usize;
lengths.push(segment_len * 8);
}
Ok(0)
}
#[cfg(test)]
pub mod test {
use super::{
MessageStream,
parse_segment_table,
serialize_segment_table,
write_message,
};
use test_utils;
use std::io::{self, Cursor, Write};
use capnp::{Word, message};
use capnp::message::ReaderSegments;
use quickcheck::{quickcheck, TestResult};
#[test]
fn test_parse_segment_table() {
fn compare(expected: &[usize], buf: &[u8]) {
let mut actual = Vec::new();
assert_eq!(0, parse_segment_table(buf, &mut actual).unwrap());
assert_eq!(expected, &*actual);
}
compare(&[0 * 8],
&[0,0,0,0,
0,0,0,0]);
compare(&[1 * 8],
&[0,0,0,0,
1,0,0,0]);
compare(&[1 * 8, 1 * 8],
&[1,0,0,0,
1,0,0,0,
1,0,0,0,
0,0,0,0]);
compare(&[1 * 8, 1 * 8, 256 * 8],
&[2,0,0,0,
1,0,0,0,
1,0,0,0,
0,1,0,0]);
compare(&[77 * 8, 23 * 8, 1 * 8, 99 * 8],
&[3,0,0,0,
77,0,0,0,
23,0,0,0,
1,0,0,0,
99,0,0,0,
0,0,0,0]);
}
#[test]
fn test_parse_invalid_segment_table() {
let mut v = Vec::new();
assert!(parse_segment_table(&[255,1,0,0,0,0,0,0], &mut v).is_err());
assert_eq!(8, parse_segment_table(&[0,0,0,0], &mut v).unwrap());
assert_eq!(8, parse_segment_table(&[0,0,0,0, 0,0,0], &mut v).unwrap());
assert_eq!(16, parse_segment_table(&[1,0,0,0, 0,0,0,0, 0,0,0], &mut v).unwrap());
assert!(parse_segment_table(&[255,255,255,255,0,0,0,0], &mut v).is_err());
}
#[test]
fn check_read_segments() {
fn read_segments(segments: Vec<Vec<Word>>) -> TestResult {
if segments.len() == 0 { return TestResult::discard(); }
let mut cursor = Cursor::new(Vec::new());
test_utils::write_message_segments(&mut cursor, &segments);
cursor.set_position(0);
let mut message_reader =
MessageStream::<_, (), ()>::new(&mut cursor, message::ReaderOptions::new());
let message = message_reader.read_message().unwrap().unwrap();
let result_segments = message.into_segments();
TestResult::from_bool(segments.iter().enumerate().all(|(i, segment)| {
&segment[..] == result_segments.get_segment(i as u32).unwrap()
}))
}
quickcheck(read_segments as fn(Vec<Vec<Word>>) -> TestResult);
}
fn write_message_segments<W>(write: &mut W, segments: &Vec<Vec<Word>>)
where W: Write {
let segments: &[&[Word]] = &segments.iter()
.map(|segment| &segment[..])
.collect::<Vec<_>>()[..];
let mut segment_table = Vec::new();
serialize_segment_table(&mut segment_table, segments);
let mut write_progress = (0, 0);
loop {
match write_message(write, &segment_table, segments, &mut write_progress) {
Err(ref error) if error.kind() == io::ErrorKind::WouldBlock => continue,
other => { other.unwrap(); return },
}
}
}
#[test]
fn check_write_segments() {
fn write_segments(segments: Vec<Vec<Word>>) -> TestResult {
if segments.len() == 0 { return TestResult::discard(); }
let mut cursor = Cursor::new(Vec::new());
let mut expected_cursor = Cursor::new(Vec::new());
test_utils::write_message_segments(&mut expected_cursor, &segments);
expected_cursor.set_position(0);
write_message_segments(&mut cursor, &segments);
TestResult::from_bool(expected_cursor.into_inner() == cursor.into_inner())
}
quickcheck(write_segments as fn(Vec<Vec<Word>>) -> TestResult);
}
#[test]
fn check_round_trip() {
fn round_trip(messages: Vec<Vec<Vec<Word>>>) -> TestResult {
let mut cursor = Cursor::new(Vec::new());
for segments in &messages {
if segments.len() == 0 { return TestResult::discard(); }
write_message_segments(&mut cursor, segments);
}
cursor.set_position(0);
let mut message_reader =
MessageStream::<_, (), ()>::new(&mut cursor, message::ReaderOptions::new());
for segments in &messages {
let message = message_reader.read_message().unwrap().unwrap();
let result_segments = message.into_segments();
for (i, segment) in segments.into_iter().enumerate() {
if &segment[..] != result_segments.get_segment(i as u32).unwrap() {
return TestResult::failed();
}
}
}
TestResult::passed()
}
quickcheck(round_trip as fn(Vec<Vec<Vec<Word>>>) -> TestResult);
}
#[test]
fn check_round_trip_nonblock() {
fn round_trip_nonblock(messages: Vec<Vec<Vec<Word>>>, frequency: usize) -> TestResult {
if frequency == 0 { return TestResult::discard(); }
let mut stream = test_utils::BlockingStream::new(Cursor::new(Vec::new()), frequency);
for segments in &messages {
if segments.len() == 0 { return TestResult::discard(); }
write_message_segments(&mut stream, segments);
}
stream.inner_mut().set_position(0);
let mut message_reader =
MessageStream::<_, (), ()>::new(&mut stream, message::ReaderOptions::new());
for segments in &messages {
let mut message = None;
while let None = message {
message = message_reader.read_message().unwrap();
}
let result_segments = message.unwrap().into_segments();
for (i, segment) in segments.into_iter().enumerate() {
if &segment[..] != result_segments.get_segment(i as u32).unwrap() {
return TestResult::failed();
}
}
}
TestResult::passed()
}
quickcheck(round_trip_nonblock as fn(Vec<Vec<Vec<Word>>>, usize) -> TestResult);
}
}