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fix some docs

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This commit is contained in:
Rob Ede
2021-12-08 05:43:50 +00:00
parent d35b7644dc
commit e49e559f47
7 changed files with 41 additions and 46 deletions
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71
actix-http/src/h1/dispatcher.rs
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@ -27,6 +27,7 @@ use crate::{
use super::{
codec::Codec,
decoder::MAX_BUFFER_SIZE,
payload::{Payload, PayloadSender, PayloadStatus},
Message, MessageType,
};
@ -793,7 +794,6 @@ where
/// Returns true when io stream can be disconnected after write to it.
///
/// It covers these conditions:
///
/// - `std::io::ErrorKind::ConnectionReset` after partial read.
/// - all data read done.
#[inline(always)]
@ -813,46 +813,39 @@ where
loop {
// Return early when read buf exceed decoder's max buffer size.
if this.read_buf.len() >= super::decoder::MAX_BUFFER_SIZE {
/*
At this point it's not known IO stream is still scheduled
to be waked up. so force wake up dispatcher just in case.
if this.read_buf.len() >= MAX_BUFFER_SIZE {
// At this point it's not known IO stream is still scheduled to be waked up so
// force wake up dispatcher just in case.
//
// Reason:
// AsyncRead mostly would only have guarantee wake up when the poll_read
// return Poll::Pending.
//
// Case:
// When read_buf is beyond max buffer size the early return could be successfully
// be parsed as a new Request. This case would not generate ParseError::TooLarge and
// at this point IO stream is not fully read to Pending and would result in
// dispatcher stuck until timeout (KA)
//
// Note:
// This is a perf choice to reduce branch on <Request as MessageType>::decode.
//
// A Request head too large to parse is only checked on
// `httparse::Status::Partial` condition.
Reason:
AsyncRead mostly would only have guarantee wake up
when the poll_read return Poll::Pending.
Case:
When read_buf is beyond max buffer size the early return
could be successfully be parsed as a new Request.
This case would not generate ParseError::TooLarge
and at this point IO stream is not fully read to Pending
and would result in dispatcher stuck until timeout (KA)
Note:
This is a perf choice to reduce branch on
<Request as MessageType>::decode.
A Request head too large to parse is only checked on
httparse::Status::Partial condition.
*/
if this.payload.is_none() {
/*
When dispatcher has a payload the responsibility of
wake up it would be shift to h1::payload::Payload.
Reason:
Self wake up when there is payload would waste poll
and/or result in over read.
Case:
When payload is (partial) dropped by user there is
no need to do read anymore.
At this case read_buf could always remain beyond
MAX_BUFFER_SIZE and self wake up would be busy poll
dispatcher and waste resource.
*/
// When dispatcher has a payload the responsibility of wake up it would be shift
// to h1::payload::Payload.
//
// Reason:
// Self wake up when there is payload would waste poll and/or result in
// over read.
//
// Case:
// When payload is (partial) dropped by user there is no need to do
// read anymore. At this case read_buf could always remain beyond
// MAX_BUFFER_SIZE and self wake up would be busy poll dispatcher and
// waste resources.
cx.waker().wake_by_ref();
}