Christopher Haster / events

Note! This project has moved to github.com/armmbed/mbed-events

Dependents:   SimpleHTTPExample

This repository has been superceded

This project has moved to mbed-events

Composable event loops combine the cheap synchronicity of event loops with the composability of preempted threads.

Two modular event queue classes are provided:

  • EventLoop - for loops coupled with a c++ managed thread
  • EventQueue - for manually managed event queues

The Event class takes advantage of the extensibility of FuncPtr to allow an event to be passed through APIs as a normal function.

More information on composable event loops.

EventQueue.cpp@5:9963a617f952, 2016-04-20 (annotated)

Committer:
Christopher Haster
Date:
Wed Apr 20 22:28:19 2016 -0500
Revision:
5:9963a617f952
Parent:
2:11cda6bead99
Child:
6:31c141d3bcc7
Fix uninitialized variable in EventQueue

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Christopher Haster 2:11cda6bead99 1 #include "EventQueue.h"
Christopher Haster 2:11cda6bead99 2 #include "Event.h"
Christopher Haster 0:b1b901ae3696 3
Christopher Haster 0:b1b901ae3696 4
Christopher Haster 2:11cda6bead99 5 EventQueue::EventQueue() {
Christopher Haster 5:9963a617f952 6 _queue = 0;
Christopher Haster 2:11cda6bead99 7 _tick = 0;
Christopher Haster 2:11cda6bead99 8 _timer.start();
Christopher Haster 2:11cda6bead99 9 _ticker.attach_us(this, &EventQueue::tick, (1 << 16) * 1000);
Christopher Haster 2:11cda6bead99 10 }
Christopher Haster 2:11cda6bead99 11
Christopher Haster 2:11cda6bead99 12 unsigned EventQueue::get_tick() {
Christopher Haster 2:11cda6bead99 13 return _tick + (unsigned)_timer.read_ms();
Christopher Haster 2:11cda6bead99 14 }
Christopher Haster 2:11cda6bead99 15
Christopher Haster 2:11cda6bead99 16 void EventQueue::tick() {
Christopher Haster 2:11cda6bead99 17 _timer.reset();
Christopher Haster 2:11cda6bead99 18 _tick += 1 << 16;
Christopher Haster 2:11cda6bead99 19 }
Christopher Haster 2:11cda6bead99 20
Christopher Haster 2:11cda6bead99 21 void EventQueue::wakeup() {
Christopher Haster 2:11cda6bead99 22
Christopher Haster 2:11cda6bead99 23 }
Christopher Haster 0:b1b901ae3696 24
Christopher Haster 1:2202c19570e5 25 void EventQueue::dispatch(int ms) {
Christopher Haster 0:b1b901ae3696 26 mbed::Timeout timeout;
Christopher Haster 2:11cda6bead99 27 struct event exit;
Christopher Haster 2:11cda6bead99 28
Christopher Haster 2:11cda6bead99 29 if (ms >= 0) {
Christopher Haster 2:11cda6bead99 30 memset(&exit, 0, sizeof exit);
Christopher Haster 2:11cda6bead99 31 event_register(&exit, ms);
Christopher Haster 2:11cda6bead99 32 }
Christopher Haster 0:b1b901ae3696 33
Christopher Haster 0:b1b901ae3696 34 while (true) {
Christopher Haster 0:b1b901ae3696 35 while (_queue) {
Christopher Haster 2:11cda6bead99 36 int diff = (int)(_queue->target - get_tick());
Christopher Haster 2:11cda6bead99 37 if (diff > 0) {
Christopher Haster 2:11cda6bead99 38 timeout.attach_us(this, &EventQueue::wakeup, diff * 1000);
Christopher Haster 2:11cda6bead99 39 break;
Christopher Haster 2:11cda6bead99 40 }
Christopher Haster 2:11cda6bead99 41
Christopher Haster 2:11cda6bead99 42 struct event *volatile e = _queue;
Christopher Haster 0:b1b901ae3696 43 _queue = _queue->next;
Christopher Haster 2:11cda6bead99 44 e->registered = false;
Christopher Haster 2:11cda6bead99 45
Christopher Haster 2:11cda6bead99 46 if (e == &exit) {
Christopher Haster 2:11cda6bead99 47 return;
Christopher Haster 2:11cda6bead99 48 }
Christopher Haster 0:b1b901ae3696 49
Christopher Haster 2:11cda6bead99 50 e->callback(e->data);
Christopher Haster 2:11cda6bead99 51
Christopher Haster 2:11cda6bead99 52 if (e->period >= 0) {
Christopher Haster 2:11cda6bead99 53 event_register(e, e->period);
Christopher Haster 2:11cda6bead99 54 }
Christopher Haster 0:b1b901ae3696 55 }
Christopher Haster 0:b1b901ae3696 56
Christopher Haster 0:b1b901ae3696 57 __WFI();
Christopher Haster 0:b1b901ae3696 58 }
Christopher Haster 0:b1b901ae3696 59 }
Christopher Haster 0:b1b901ae3696 60
Christopher Haster 2:11cda6bead99 61 void EventQueue::event_register(struct event *event, int ms) {
Christopher Haster 2:11cda6bead99 62 if (event->registered) {
Christopher Haster 2:11cda6bead99 63 return;
Christopher Haster 2:11cda6bead99 64 }
Christopher Haster 2:11cda6bead99 65
Christopher Haster 2:11cda6bead99 66 event->target = get_tick() + (unsigned)ms;
Christopher Haster 2:11cda6bead99 67 event->registered = true;
Christopher Haster 2:11cda6bead99 68
Christopher Haster 0:b1b901ae3696 69 __disable_irq();
Christopher Haster 2:11cda6bead99 70 struct event *volatile *p = &_queue;
Christopher Haster 2:11cda6bead99 71 while (*p && (*p)->target < event->target) {
Christopher Haster 2:11cda6bead99 72 p = &(*p)->next;
Christopher Haster 0:b1b901ae3696 73 }
Christopher Haster 2:11cda6bead99 74
Christopher Haster 2:11cda6bead99 75 event->next = *p;
Christopher Haster 2:11cda6bead99 76 *p = event;
Christopher Haster 0:b1b901ae3696 77 __enable_irq();
Christopher Haster 0:b1b901ae3696 78 }
Christopher Haster 0:b1b901ae3696 79
Christopher Haster 0:b1b901ae3696 80 void EventQueue::event_unregister(struct event *event) {
Christopher Haster 0:b1b901ae3696 81 __disable_irq();
Christopher Haster 1:2202c19570e5 82 for (struct event *volatile *p = &_queue; *p; p = &(*p)->next) {
Christopher Haster 0:b1b901ae3696 83 if (*p == event) {
Christopher Haster 0:b1b901ae3696 84 *p = event->next;
Christopher Haster 0:b1b901ae3696 85 break;
Christopher Haster 0:b1b901ae3696 86 }
Christopher Haster 0:b1b901ae3696 87 }
Christopher Haster 0:b1b901ae3696 88 __enable_irq();
Christopher Haster 0:b1b901ae3696 89 }
Christopher Haster 0:b1b901ae3696 90