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more docs for event manager

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Robin Müller 2022-10-28 02:02:28 +02:00
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170
fsrc-core/src/event_man.rs
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@ -1,5 +1,25 @@
//! Event management and forwarding
use crate::events::{EventU16TypedSev, EventU32, GenericEvent, HasSeverity};
//!
//! This module provides components to perform event routing. The most important component for this
//! task is the [EventManager]. It has a map of event listeners and uses a dynamic [EventReceiver]
//! instance to receive all events and then route them to event subscribers where appropriate.
//!
//! One common use case for satellite systems is to offer a light-weight publish-subscribe mechanism
//! and IPC mechanism for software and hardware events which are also packaged as telemetry.
//! This can be done with the [EventManager] like this:
//!
//! 1. Provide a concrete [SendEventProvider] implementation and a concrete [EventReceiver]
//! implementation. These abstraction allow to use different message queue backends.
//! A straightforward implementation where dynamic memory allocation is not a big concern could
//! use [std::sync::mpsc::channel] to do this. It is recommended that these implementations
//! derive [Clone].
//! 2. Each event creator gets a sender component which allows it to send events to the manager.
//! 3. The event manager receives all receiver ends so all events are routed to the
//! manager.
//! 4. Each event receiver and/or subscriber gets a receiver component. The sender component is
//! used with the [SendEventProvider] trait and the subscription API provided by the
//! [EventManager] to subscribe for individual events or whole group of events.
use crate::events::{GenericEvent, LargestEventRaw, LargestGroupIdRaw};
use alloc::boxed::Box;
use alloc::vec;
use alloc::vec::Vec;
@ -7,32 +27,42 @@ use hashbrown::HashMap;
#[derive(PartialEq, Eq, Hash, Copy, Clone)]
enum ListenerType {
Single(u32),
Group(u16),
Single(LargestEventRaw),
Group(LargestGroupIdRaw),
All,
}
pub trait EventListener<Provider: GenericEvent> {
pub trait SendEventProvider<Provider: GenericEvent> {
type Error;
fn id(&self) -> u32;
fn send_to_no_data(&mut self, event: Provider) -> Result<(), Self::Error> {
self.send_to(event, None)
fn send_no_data(&mut self, event: Provider) -> Result<(), Self::Error> {
self.send(event, None)
}
fn send_to(&mut self, event: Provider, aux_data: Option<&[u8]>) -> Result<(), Self::Error>;
fn send(&mut self, event: Provider, aux_data: Option<&[u8]>) -> Result<(), Self::Error>;
}
struct Listener<E, Provider: GenericEvent> {
struct Listener<E, Event: GenericEvent> {
ltype: ListenerType,
dest: Box<dyn EventListener<Provider, Error = E>>,
send_provider: Box<dyn SendEventProvider<Event, Error = E>>,
}
pub trait ReceivesAllEvent<Provider: GenericEvent> {
fn receive(&mut self) -> Option<(Provider, Option<&[u8]>)>;
/// Generic abstraction for an event receiver.
pub trait EventReceiver<Event: GenericEvent> {
/// This function has to be provided by any event receiver. A receive call may or may not return
/// an event.
///
/// To allow returning arbitrary additional auxiliary data, a mutable slice is passed to the
/// [Self::receive] call as well. Receivers can write data to this slice, but care must be taken
/// to avoid panics due to size missmatches or out of bound writes.
fn receive(&mut self, aux_data: &mut [u8]) -> Option<Event>;
}
pub struct EventManager<E, Provider: GenericEvent> {
listeners: HashMap<ListenerType, Vec<Listener<E, Provider>>>,
event_receiver: Box<dyn ReceivesAllEvent<Provider>>,
/// Generic event manager implementation.
pub struct EventManager<E, Event: GenericEvent> {
aux_data_buf: Vec<u8>,
listeners: HashMap<ListenerType, Vec<Listener<E, Event>>>,
event_receiver: Box<dyn EventReceiver<Event>>,
}
pub enum HandlerResult<Provider: GenericEvent> {
@ -40,48 +70,50 @@ pub enum HandlerResult<Provider: GenericEvent> {
Handled(u32, Provider),
}
impl<E> EventManager<E, EventU32> {
pub fn new(event_receiver: Box<dyn ReceivesAllEvent<EventU32>>) -> Self {
impl<E, Event: GenericEvent + Copy> EventManager<E, Event> {
pub fn new(event_receiver: Box<dyn EventReceiver<Event>>, buf_len_aux_data: usize) -> Self {
EventManager {
aux_data_buf: vec![0; buf_len_aux_data],
listeners: HashMap::new(),
event_receiver,
}
}
}
impl<E> EventManager<E, EventU32> {
pub fn subscribe_single(
&mut self,
event: EventU32,
dest: impl EventListener<EventU32, Error = E> + 'static,
event: Event,
dest: impl SendEventProvider<Event, Error = E> + 'static,
) {
self.update_listeners(ListenerType::Single(event.raw_as_largest_type()), dest);
}
pub fn subscribe_group(
&mut self,
group_id: <EventU32 as GenericEvent>::GroupId,
dest: impl EventListener<EventU32, Error = E> + 'static,
group_id: LargestGroupIdRaw,
dest: impl SendEventProvider<Event, Error = E> + 'static,
) {
self.update_listeners(ListenerType::Group(group_id), dest);
}
}
impl<E, SEVERITY: HasSeverity + Copy> EventManager<E, EventU16TypedSev<SEVERITY>> {
pub fn subscribe_single(
&mut self,
event: EventU16TypedSev<SEVERITY>,
dest: impl EventListener<EventU16TypedSev<SEVERITY>, Error = E> + 'static,
) {
self.update_listeners(ListenerType::Single(event.raw_as_largest_type()), dest);
pub fn subscribe_all(&mut self, dest: impl SendEventProvider<Event, Error = E> + 'static) {
self.update_listeners(ListenerType::All, dest);
}
pub fn subscribe_group(
/// Helper function which removes single subscriptions for which a group subscription already
/// exists.
pub fn remove_single_subscriptions_for_group(
&mut self,
group_id: <EventU16TypedSev<SEVERITY> as GenericEvent>::GroupId,
dest: impl EventListener<EventU16TypedSev<SEVERITY>, Error = E> + 'static,
group_id: LargestGroupIdRaw,
dest: impl SendEventProvider<Event, Error=E> + 'static
) {
self.update_listeners(ListenerType::Group(group_id.into()), dest);
if self.listeners.contains_key(&ListenerType::Group(group_id)) {
for (ltype, listeners) in &mut self.listeners {
if let ListenerType::Single(_) = ltype {
listeners.retain(|f| {
f.send_provider.id() != dest.id()
});
}
}
}
}
}
@ -89,27 +121,27 @@ impl<E, Provider: GenericEvent + Copy> EventManager<E, Provider> {
fn update_listeners(
&mut self,
key: ListenerType,
dest: impl EventListener<Provider, Error = E> + 'static,
dest: impl SendEventProvider<Provider, Error = E> + 'static,
) {
if !self.listeners.contains_key(&key) {
self.listeners.insert(
key,
vec![Listener {
ltype: key,
dest: Box::new(dest),
send_provider: Box::new(dest),
}],
);
} else {
let vec = self.listeners.get_mut(&key).unwrap();
// To prevent double insertions
for entry in vec.iter() {
if entry.ltype == key && entry.dest.id() == dest.id() {
if entry.ltype == key && entry.send_provider.id() == dest.id() {
return;
}
}
vec.push(Listener {
ltype: key,
dest: Box::new(dest),
send_provider: Box::new(dest),
});
}
}
@ -120,25 +152,35 @@ impl<E, Provider: GenericEvent + Copy> EventManager<E, Provider> {
let mut send_handler =
|event: Provider, aux_data: Option<&[u8]>, llist: &mut Vec<Listener<E, Provider>>| {
for listener in llist.iter_mut() {
if let Err(e) = listener.dest.send_to(event, aux_data) {
if let Err(e) = listener.send_provider.send(event, aux_data) {
err_status = Some(Err(e));
} else {
num_recipients += 1;
}
}
};
if let Some((event, aux_data)) = self.event_receiver.receive() {
if let Some(event) = self
.event_receiver
.receive(self.aux_data_buf.as_mut_slice())
{
let single_key = ListenerType::Single(event.raw_as_largest_type());
if self.listeners.contains_key(&single_key) {
send_handler(
event,
aux_data,
Some(self.aux_data_buf.as_slice()),
self.listeners.get_mut(&single_key).unwrap(),
);
}
let group_key = ListenerType::Group(event.group_id_as_largest_type());
if self.listeners.contains_key(&group_key) {
send_handler(event, aux_data, self.listeners.get_mut(&group_key).unwrap());
send_handler(
event,
Some(self.aux_data_buf.as_slice()),
self.listeners.get_mut(&group_key).unwrap(),
);
}
if let Some(all_receivers) = self.listeners.get_mut(&ListenerType::All) {
send_handler(event, Some(self.aux_data_buf.as_slice()), all_receivers);
}
if let Some(err) = err_status {
return err;
@ -151,24 +193,30 @@ impl<E, Provider: GenericEvent + Copy> EventManager<E, Provider> {
#[cfg(test)]
mod tests {
use super::{EventListener, HandlerResult, ReceivesAllEvent};
use super::{EventReceiver, HandlerResult, SendEventProvider};
use crate::event_man::EventManager;
use crate::events::{EventU32, GenericEvent, Severity};
use alloc::boxed::Box;
use std::sync::mpsc::{channel, Receiver, SendError, Sender};
use std::thread;
use std::time::Duration;
use std::{thread, vec};
use vec::Vec;
type EventAndParams<'a> = (EventU32, Option<&'a [u8]>);
struct EventReceiver<'a> {
mpsc_receiver: Receiver<EventAndParams<'a>>,
struct MpscEventReceiver {
mpsc_receiver: Receiver<(EventU32, Option<Vec<u8>>)>,
}
impl ReceivesAllEvent<EventU32> for EventReceiver<'_> {
fn receive(&mut self) -> Option<(EventU32, Option<&[u8]>)> {
if let Some((event, _params)) = self.mpsc_receiver.try_recv().ok() {
return Some((event, None));
impl EventReceiver<EventU32> for MpscEventReceiver {
fn receive(&mut self, aux_data: &mut [u8]) -> Option<EventU32> {
if let Some((event, params)) = self.mpsc_receiver.try_recv().ok() {
if let Some(params) = params {
if params.len() < aux_data.len() {
aux_data[0..params.len()].copy_from_slice(params.as_slice())
}
}
return Some(event);
}
None
}
@ -180,17 +228,13 @@ mod tests {
mpsc_sender: Sender<EventAndParams<'a>>,
}
impl<'a> EventListener<EventU32> for MpscEventSenderQueue<'a> {
impl<'a> SendEventProvider<EventU32> for MpscEventSenderQueue<'a> {
type Error = SendError<EventAndParams<'a>>;
fn id(&self) -> u32 {
self.id
}
fn send_to(
&mut self,
event: EventU32,
_aux_data: Option<&[u8]>,
) -> Result<(), Self::Error> {
fn send(&mut self, event: EventU32, _aux_data: Option<&[u8]>) -> Result<(), Self::Error> {
self.mpsc_sender.send((event, None))
}
}
@ -220,11 +264,11 @@ mod tests {
#[test]
fn test_basic() {
let (event_sender, manager_queue) = channel();
let event_man_receiver = EventReceiver {
let event_man_receiver = MpscEventReceiver {
mpsc_receiver: manager_queue,
};
let mut event_man: EventManager<SendError<EventAndParams>, EventU32> =
EventManager::new(Box::new(event_man_receiver));
EventManager::new(Box::new(event_man_receiver), 128);
let event_grp_0 = EventU32::new(Severity::INFO, 0, 0).unwrap();
let event_grp_1_0 = EventU32::new(Severity::HIGH, 1, 0).unwrap();
let (single_event_sender, single_event_receiver) = channel();
@ -263,11 +307,11 @@ mod tests {
#[test]
fn test_multi_group() {
let (event_sender, manager_queue) = channel();
let event_man_receiver = EventReceiver {
let event_man_receiver = MpscEventReceiver {
mpsc_receiver: manager_queue,
};
let mut event_man: EventManager<SendError<EventAndParams>, EventU32> =
EventManager::new(Box::new(event_man_receiver));
EventManager::new(Box::new(event_man_receiver), 128);
let res = event_man.try_event_handling();
assert!(res.is_ok());
let hres = res.unwrap();
@ -305,11 +349,11 @@ mod tests {
#[test]
fn test_listening_to_same_event_and_multi_type() {
let (event_sender, manager_queue) = channel();
let event_man_receiver = EventReceiver {
let event_man_receiver = MpscEventReceiver {
mpsc_receiver: manager_queue,
};
let mut event_man: EventManager<SendError<EventAndParams>, EventU32> =
EventManager::new(Box::new(event_man_receiver));
EventManager::new(Box::new(event_man_receiver), 128);
let event_0 = EventU32::new(Severity::INFO, 0, 5).unwrap();
let event_1 = EventU32::new(Severity::HIGH, 1, 0).unwrap();
let (event_0_tx_0, event_0_rx_0) = channel();