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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use std::fmt;
use neqo_transport::StreamId;
use sfv::{BareItem, Item, ListEntry, Parser};
use crate::{frames::HFrame, Error, Header, Res};
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub struct Priority {
urgency: u8,
incremental: bool,
}
impl Default for Priority {
fn default() -> Self {
Priority {
urgency: 3,
incremental: false,
}
}
}
impl Priority {
/// # Panics
///
/// If an invalid urgency (>7 is given)
#[must_use]
pub fn new(urgency: u8, incremental: bool) -> Priority {
assert!(urgency < 8);
Priority {
urgency,
incremental,
}
}
/// Returns a header if required to send
#[must_use]
pub fn header(self) -> Option<Header> {
match self {
Priority {
urgency: 3,
incremental: false,
} => None,
other => Some(Header::new("priority", format!("{other}"))),
}
}
/// Constructs a priority from raw bytes (either a field value of frame content).
///
/// # Errors
///
/// When the contained syntax is invalid.
///
/// # Panics
///
/// Never, but the compiler is not smart enough to work that out.
pub fn from_bytes(bytes: &[u8]) -> Res<Priority> {
let dict = Parser::parse_dictionary(bytes).map_err(|_| Error::HttpFrame)?;
let urgency = match dict.get("u") {
Some(ListEntry::Item(Item {
bare_item: BareItem::Integer(u),
..
})) if (0..=7).contains(u) => u8::try_from(*u).unwrap(),
_ => 3,
};
let incremental = match dict.get("i") {
Some(ListEntry::Item(Item {
bare_item: BareItem::Boolean(i),
..
})) => *i,
_ => false,
};
Ok(Priority {
urgency,
incremental,
})
}
}
impl fmt::Display for Priority {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Priority {
urgency: 3,
incremental: false,
} => Ok(()),
Priority {
urgency: 3,
incremental: true,
} => write!(f, "i"),
Priority {
urgency,
incremental: false,
} => write!(f, "u={urgency}"),
Priority {
urgency,
incremental: true,
} => write!(f, "u={urgency},i"),
}
}
}
#[derive(Debug)]
#[allow(clippy::module_name_repetitions)]
pub struct PriorityHandler {
push_stream: bool,
priority: Priority,
last_send_priority: Priority,
}
impl PriorityHandler {
pub fn new(push_stream: bool, priority: Priority) -> PriorityHandler {
PriorityHandler {
push_stream,
priority,
last_send_priority: priority,
}
}
/*pub fn priority(&self) -> Priority {
self.priority
}*/
/// Returns if an priority update will be issued
pub fn maybe_update_priority(&mut self, priority: Priority) -> bool {
if priority == self.priority {
false
} else {
self.priority = priority;
true
}
}
pub fn priority_update_sent(&mut self) {
self.last_send_priority = self.priority;
}
/// Returns `HFrame` if an priority update is outstanding
pub fn maybe_encode_frame(&self, stream_id: StreamId) -> Option<HFrame> {
if self.priority == self.last_send_priority {
None
} else if self.push_stream {
Some(HFrame::PriorityUpdatePush {
element_id: stream_id.as_u64(),
priority: self.priority,
})
} else {
Some(HFrame::PriorityUpdateRequest {
element_id: stream_id.as_u64(),
priority: self.priority,
})
}
}
}
#[cfg(test)]
mod test {
use neqo_transport::StreamId;
use crate::{priority::PriorityHandler, HFrame, Priority};
#[test]
fn priority_updates_ignore_same() {
let mut p = PriorityHandler::new(false, Priority::new(5, false));
assert!(!p.maybe_update_priority(Priority::new(5, false)));
// updating with the same priority -> there should not be any priority frame sent
assert!(p.maybe_encode_frame(StreamId::new(4)).is_none());
}
#[test]
fn priority_updates_send_update() {
let mut p = PriorityHandler::new(false, Priority::new(5, false));
assert!(p.maybe_update_priority(Priority::new(6, false)));
// updating with the a different priority -> there should be a priority frame sent
assert!(p.maybe_encode_frame(StreamId::new(4)).is_some());
}
#[test]
fn multiple_priority_updates_ignore_same() {
let mut p = PriorityHandler::new(false, Priority::new(5, false));
assert!(p.maybe_update_priority(Priority::new(6, false)));
assert!(p.maybe_update_priority(Priority::new(5, false)));
// initial and last priority same -> there should not be any priority frame sent
assert!(p.maybe_encode_frame(StreamId::new(4)).is_none());
}
#[test]
fn multiple_priority_updates_send_update() {
let mut p = PriorityHandler::new(false, Priority::new(5, false));
assert!(p.maybe_update_priority(Priority::new(6, false)));
assert!(p.maybe_update_priority(Priority::new(7, false)));
// updating two times with a different priority -> the last priority update should be in the
// next frame
let expected = HFrame::PriorityUpdateRequest {
element_id: 4,
priority: Priority::new(7, false),
};
assert_eq!(p.maybe_encode_frame(StreamId::new(4)), Some(expected));
}
#[test]
fn priority_updates_incremental() {
let mut p = PriorityHandler::new(false, Priority::new(5, false));
assert!(p.maybe_update_priority(Priority::new(5, true)));
// updating the incremental parameter -> there should be a priority frame sent
let expected = HFrame::PriorityUpdateRequest {
element_id: 4,
priority: Priority::new(5, true),
};
assert_eq!(p.maybe_encode_frame(StreamId::new(4)), Some(expected));
}
}