src/client/merge_known_chunks.rs: avoid VecDequeu - a single buffer is enough

This commit is contained in:
Dietmar Maurer 2019-05-24 07:36:09 +02:00
parent 2dbba78b98
commit ecb21b4794

View File

@ -1,6 +1,6 @@
use failure::*;
use futures::*;
use std::collections::{VecDeque, HashSet};
use std::collections::HashSet;
use std::sync::{Arc, Mutex};
pub struct ChunkInfo {
@ -21,14 +21,14 @@ pub trait MergeKnownChunks: Sized {
pub struct MergeKnownChunksQueue<S> {
input: S,
known_chunks: Arc<Mutex<HashSet<[u8;32]>>>,
queue: VecDeque<MergedChunkInfo>,
buffer: Option<MergedChunkInfo>,
}
impl <S> MergeKnownChunks for S
where S: Stream<Item=ChunkInfo, Error=Error>,
{
fn merge_known_chunks(self, known_chunks: Arc<Mutex<HashSet<[u8;32]>>>) -> MergeKnownChunksQueue<Self> {
MergeKnownChunksQueue { input: self, known_chunks, queue: VecDeque::new() }
MergeKnownChunksQueue { input: self, known_chunks, buffer: None }
}
}
@ -40,19 +40,6 @@ impl <S> Stream for MergeKnownChunksQueue<S>
fn poll(&mut self) -> Poll<Option<MergedChunkInfo>, Error> {
loop {
if let Some(first) = self.queue.front() {
if let MergedChunkInfo::New(_) = first {
return Ok(Async::Ready(self.queue.pop_front()));
} else if self.queue.len() > 1 {
return Ok(Async::Ready(self.queue.pop_front()));
} else if let MergedChunkInfo::Known(list) = first {
if list.len() >= 64 {
return Ok(Async::Ready(self.queue.pop_front()));
}
}
}
match self.input.poll() {
Err(err) => {
return Err(err);
@ -61,10 +48,10 @@ impl <S> Stream for MergeKnownChunksQueue<S>
return Ok(Async::NotReady);
}
Ok(Async::Ready(None)) => {
if let Some(item) = self.queue.pop_front() {
return Ok(Async::Ready(Some(item)));
if let Some(last) = self.buffer.take() {
return Ok(Async::Ready(Some(last)));
} else {
return Ok(Async::Ready(None));
return Ok(Async::Ready(None));
}
}
Ok(Async::Ready(Some(chunk_info))) => {
@ -74,21 +61,39 @@ impl <S> Stream for MergeKnownChunksQueue<S>
if chunk_is_known {
if let Some(last) = self.queue.back_mut() {
if let MergedChunkInfo::Known(list) = last {
list.push(chunk_info);
} else {
let result = MergedChunkInfo::Known(vec![chunk_info]);
self.queue.push_back(result);
let last = self.buffer.take();
match last {
None => {
self.buffer = Some(MergedChunkInfo::Known(vec![chunk_info]));
// continue
}
Some(MergedChunkInfo::Known(mut list)) => {
list.push(chunk_info);
let len = list.len();
self.buffer = Some(MergedChunkInfo::Known(list));
if len >= 64 {
return Ok(Async::Ready(self.buffer.take()));
}
// continue
}
Some(MergedChunkInfo::New(_)) => {
self.buffer = Some(MergedChunkInfo::Known(vec![chunk_info]));
return Ok(Async::Ready(last));
}
} else {
let result = MergedChunkInfo::Known(vec![chunk_info]);
self.queue.push_back(result);
}
} else {
known_chunks.insert(chunk_info.digest);
let result = MergedChunkInfo::New(chunk_info);
self.queue.push_back(result);
let new = MergedChunkInfo::New(chunk_info);
if let Some(last) = self.buffer.take() {
self.buffer = Some(new);
return Ok(Async::Ready(Some(last)));
} else {
return Ok(Async::Ready(Some(new)));
}
}
}
}