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use std::collections::HashMap;
use super::{
sequence_buffer::{SequenceBuffer, SequenceNumber},
standard_header::StandardHeader,
wrapping_number::sequence_greater_than,
};
use super::{
actors::actor_notifiable::ActorNotifiable,
events::{event_manager::EventManager, event_type::EventType},
packet_type::PacketType,
};
const REDUNDANT_PACKET_ACKS_SIZE: u16 = 32;
const DEFAULT_SEND_PACKETS_SIZE: usize = 256;
#[derive(Debug)]
pub struct AckManager {
sequence_number: SequenceNumber,
remote_ack_sequence_num: SequenceNumber,
sent_packets: HashMap<u16, SentPacket>,
received_packets: SequenceBuffer<ReceivedPacket>,
}
impl AckManager {
pub fn new() -> Self {
AckManager {
sequence_number: 0,
remote_ack_sequence_num: u16::max_value(),
sent_packets: HashMap::with_capacity(DEFAULT_SEND_PACKETS_SIZE),
received_packets: SequenceBuffer::with_capacity(REDUNDANT_PACKET_ACKS_SIZE + 1),
}
}
pub fn get_local_packet_index(&self) -> SequenceNumber {
self.sequence_number
}
pub fn process_incoming<T: EventType>(
&mut self,
header: &StandardHeader,
event_manager: &mut EventManager<T>,
actor_notifiable: &mut Option<&mut dyn ActorNotifiable>,
) {
let remote_seq_num = header.local_packet_index();
let remote_ack_seq = header.last_remote_packet_index();
let mut remote_ack_field = header.ack_field();
self.received_packets
.insert(remote_seq_num, ReceivedPacket {});
if sequence_greater_than(remote_ack_seq, self.remote_ack_sequence_num) {
self.remote_ack_sequence_num = remote_ack_seq;
}
if let Some(sent_packet) = self.sent_packets.get(&remote_ack_seq) {
if sent_packet.packet_type == PacketType::Data {
self.notify_packet_delivered(remote_ack_seq, event_manager, actor_notifiable);
}
self.sent_packets.remove(&remote_ack_seq);
}
for i in 1..=REDUNDANT_PACKET_ACKS_SIZE {
let ack_sequence = remote_ack_seq.wrapping_sub(i);
if let Some(sent_packet) = self.sent_packets.get(&ack_sequence) {
if remote_ack_field & 1 == 1 {
if sent_packet.packet_type == PacketType::Data {
self.notify_packet_delivered(ack_sequence, event_manager, actor_notifiable);
}
self.sent_packets.remove(&ack_sequence);
} else {
if sent_packet.packet_type == PacketType::Data {
self.notify_packet_dropped(ack_sequence, event_manager, actor_notifiable);
}
self.sent_packets.remove(&ack_sequence);
}
}
remote_ack_field >>= 1;
}
}
pub fn track_packet(&mut self, packet_type: PacketType, sequence_number: SequenceNumber) {
self.sent_packets.insert(
sequence_number,
SentPacket {
id: sequence_number as u32,
packet_type,
},
);
}
pub fn increment_local_packet_index(&mut self) {
self.sequence_number = self.sequence_number.wrapping_add(1);
}
fn notify_packet_delivered<T: EventType>(
&self,
packet_sequence_number: u16,
event_manager: &mut EventManager<T>,
actor_notifiable: &mut Option<&mut dyn ActorNotifiable>,
) {
event_manager.notify_packet_delivered(packet_sequence_number);
if let Some(notifiable) = actor_notifiable {
notifiable.notify_packet_delivered(packet_sequence_number);
}
}
fn notify_packet_dropped<T: EventType>(
&self,
packet_sequence_number: u16,
event_manager: &mut EventManager<T>,
actor_notifiable: &mut Option<&mut dyn ActorNotifiable>,
) {
event_manager.notify_packet_dropped(packet_sequence_number);
if let Some(notifiable) = actor_notifiable {
notifiable.notify_packet_dropped(packet_sequence_number);
}
}
pub(crate) fn get_last_remote_packet_index(&self) -> SequenceNumber {
self.received_packets.sequence_num().wrapping_sub(1)
}
pub(crate) fn get_ack_bitfield(&self) -> u32 {
let most_recent_remote_seq_num: u16 = self.get_last_remote_packet_index();
let mut ack_bitfield: u32 = 0;
let mut mask: u32 = 1;
for i in 1..=REDUNDANT_PACKET_ACKS_SIZE {
let sequence = most_recent_remote_seq_num.wrapping_sub(i);
if self.received_packets.exists(sequence) {
ack_bitfield |= mask;
}
mask <<= 1;
}
ack_bitfield
}
}
#[derive(Clone, Debug, PartialEq)]
pub struct SentPacket {
pub id: u32,
pub packet_type: PacketType,
}
#[derive(Clone, Debug, Default)]
pub struct ReceivedPacket;