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This repository has been superceded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@14:5abf2ccf2dbf, 2016-05-10 (annotated)

Committer:
Christopher Haster
Date:
Tue May 10 07:51:44 2016 -0500
Revision:
14:5abf2ccf2dbf
Parent:
10:62767e708bb6
Child:
15:92d7c0b8a0f5
Move to internal memory management



Allows an event to be enqueued multiple times before being handled.

Downside is cancel is non-trivial to support.

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 10:62767e708bb6 3 #include "mbed.h"
Christopher Haster 0:b1b901ae3696 4
Christopher Haster 9:2b0910397844 5 #ifndef EVENTS_NO_RTOS
Christopher Haster 9:2b0910397844 6 #include "rtos.h"
Christopher Haster 9:2b0910397844 7 #endif
Christopher Haster 9:2b0910397844 8
Christopher Haster 0:b1b901ae3696 9
Christopher Haster 14:5abf2ccf2dbf 10
Christopher Haster 14:5abf2ccf2dbf 11 EventQueue::EventQueue(unsigned event_count, unsigned event_context) {
Christopher Haster 14:5abf2ccf2dbf 12 _event_context = sizeof(FuncPtr<void()>) + event_context;
Christopher Haster 14:5abf2ccf2dbf 13 unsigned event_size = sizeof(struct event) + _event_context;
Christopher Haster 14:5abf2ccf2dbf 14 _mem = malloc(event_count * event_size);
Christopher Haster 14:5abf2ccf2dbf 15 _free = (struct event*)_mem;
Christopher Haster 14:5abf2ccf2dbf 16
Christopher Haster 14:5abf2ccf2dbf 17 if (_mem) {
Christopher Haster 14:5abf2ccf2dbf 18 for (unsigned i = 0; i < event_count-1; i++) {
Christopher Haster 14:5abf2ccf2dbf 19 ((struct event*)((char*)_mem + i*event_size))->next =
Christopher Haster 14:5abf2ccf2dbf 20 (struct event*)((char*)_mem + (i+1)*event_size);
Christopher Haster 14:5abf2ccf2dbf 21 }
Christopher Haster 14:5abf2ccf2dbf 22 ((struct event*)((char*)_mem + (event_count-1)*event_size))->next = 0;
Christopher Haster 14:5abf2ccf2dbf 23 }
Christopher Haster 14:5abf2ccf2dbf 24
Christopher Haster 5:9963a617f952 25 _queue = 0;
Christopher Haster 2:11cda6bead99 26 _tick = 0;
Christopher Haster 2:11cda6bead99 27 _timer.start();
Christopher Haster 2:11cda6bead99 28 _ticker.attach_us(this, &EventQueue::tick, (1 << 16) * 1000);
Christopher Haster 2:11cda6bead99 29 }
Christopher Haster 2:11cda6bead99 30
Christopher Haster 14:5abf2ccf2dbf 31 EventQueue::~EventQueue() {
Christopher Haster 14:5abf2ccf2dbf 32 free(_mem);
Christopher Haster 14:5abf2ccf2dbf 33 }
Christopher Haster 14:5abf2ccf2dbf 34
Christopher Haster 2:11cda6bead99 35 unsigned EventQueue::get_tick() {
Christopher Haster 2:11cda6bead99 36 return _tick + (unsigned)_timer.read_ms();
Christopher Haster 2:11cda6bead99 37 }
Christopher Haster 2:11cda6bead99 38
Christopher Haster 2:11cda6bead99 39 void EventQueue::tick() {
Christopher Haster 2:11cda6bead99 40 _timer.reset();
Christopher Haster 2:11cda6bead99 41 _tick += 1 << 16;
Christopher Haster 2:11cda6bead99 42 }
Christopher Haster 2:11cda6bead99 43
Christopher Haster 2:11cda6bead99 44 void EventQueue::wakeup() {
Christopher Haster 2:11cda6bead99 45
Christopher Haster 2:11cda6bead99 46 }
Christopher Haster 0:b1b901ae3696 47
Christopher Haster 1:2202c19570e5 48 void EventQueue::dispatch(int ms) {
Christopher Haster 10:62767e708bb6 49 Timeout timeout;
Christopher Haster 2:11cda6bead99 50 struct event exit;
Christopher Haster 2:11cda6bead99 51
Christopher Haster 2:11cda6bead99 52 if (ms >= 0) {
Christopher Haster 14:5abf2ccf2dbf 53 trigger(&exit, ms);
Christopher Haster 2:11cda6bead99 54 }
Christopher Haster 0:b1b901ae3696 55
Christopher Haster 0:b1b901ae3696 56 while (true) {
Christopher Haster 0:b1b901ae3696 57 while (_queue) {
Christopher Haster 2:11cda6bead99 58 int diff = (int)(_queue->target - get_tick());
Christopher Haster 2:11cda6bead99 59 if (diff > 0) {
Christopher Haster 2:11cda6bead99 60 timeout.attach_us(this, &EventQueue::wakeup, diff * 1000);
Christopher Haster 2:11cda6bead99 61 break;
Christopher Haster 2:11cda6bead99 62 }
Christopher Haster 2:11cda6bead99 63
Christopher Haster 2:11cda6bead99 64 struct event *volatile e = _queue;
Christopher Haster 0:b1b901ae3696 65 _queue = _queue->next;
Christopher Haster 2:11cda6bead99 66
Christopher Haster 2:11cda6bead99 67 if (e == &exit) {
Christopher Haster 2:11cda6bead99 68 return;
Christopher Haster 2:11cda6bead99 69 }
Christopher Haster 0:b1b901ae3696 70
Christopher Haster 14:5abf2ccf2dbf 71 e->dispatch(reinterpret_cast<void *>(e + 1));
Christopher Haster 2:11cda6bead99 72
Christopher Haster 2:11cda6bead99 73 if (e->period >= 0) {
Christopher Haster 14:5abf2ccf2dbf 74 trigger(e, e->period);
Christopher Haster 14:5abf2ccf2dbf 75 } else {
Christopher Haster 14:5abf2ccf2dbf 76 dealloc(e);
Christopher Haster 2:11cda6bead99 77 }
Christopher Haster 0:b1b901ae3696 78 }
Christopher Haster 0:b1b901ae3696 79
Christopher Haster 9:2b0910397844 80 #ifndef EVENTS_NO_RTOS
Christopher Haster 9:2b0910397844 81 Thread::yield();
Christopher Haster 9:2b0910397844 82 #else
Christopher Haster 0:b1b901ae3696 83 __WFI();
Christopher Haster 9:2b0910397844 84 #endif
Christopher Haster 0:b1b901ae3696 85 }
Christopher Haster 0:b1b901ae3696 86 }
Christopher Haster 0:b1b901ae3696 87
Christopher Haster 14:5abf2ccf2dbf 88 void EventQueue::trigger(struct event *e, int delay) {
Christopher Haster 14:5abf2ccf2dbf 89 e->target = get_tick() + (unsigned)delay;
Christopher Haster 2:11cda6bead99 90
Christopher Haster 6:31c141d3bcc7 91 uint32_t primask = __get_PRIMASK();
Christopher Haster 0:b1b901ae3696 92 __disable_irq();
Christopher Haster 6:31c141d3bcc7 93
Christopher Haster 2:11cda6bead99 94 struct event *volatile *p = &_queue;
Christopher Haster 14:5abf2ccf2dbf 95 while (*p && (*p)->target < e->target) {
Christopher Haster 2:11cda6bead99 96 p = &(*p)->next;
Christopher Haster 0:b1b901ae3696 97 }
Christopher Haster 2:11cda6bead99 98
Christopher Haster 14:5abf2ccf2dbf 99 e->next = *p;
Christopher Haster 14:5abf2ccf2dbf 100 *p = e;
Christopher Haster 6:31c141d3bcc7 101
Christopher Haster 7:dcd589b578ca 102 __set_PRIMASK(primask);
Christopher Haster 0:b1b901ae3696 103 }
Christopher Haster 0:b1b901ae3696 104
Christopher Haster 14:5abf2ccf2dbf 105 EventQueue::event *EventQueue::alloc(unsigned size, int ms) {
Christopher Haster 14:5abf2ccf2dbf 106 if (size > _event_context) {
Christopher Haster 14:5abf2ccf2dbf 107 return 0;
Christopher Haster 14:5abf2ccf2dbf 108 }
Christopher Haster 14:5abf2ccf2dbf 109
Christopher Haster 14:5abf2ccf2dbf 110 struct event *e;
Christopher Haster 14:5abf2ccf2dbf 111
Christopher Haster 6:31c141d3bcc7 112 uint32_t primask = __get_PRIMASK();
Christopher Haster 0:b1b901ae3696 113 __disable_irq();
Christopher Haster 6:31c141d3bcc7 114
Christopher Haster 14:5abf2ccf2dbf 115 e = _free;
Christopher Haster 14:5abf2ccf2dbf 116 if (e) {
Christopher Haster 14:5abf2ccf2dbf 117 _free = e->next;
Christopher Haster 0:b1b901ae3696 118 }
Christopher Haster 6:31c141d3bcc7 119
Christopher Haster 7:dcd589b578ca 120 __set_PRIMASK(primask);
Christopher Haster 14:5abf2ccf2dbf 121
Christopher Haster 14:5abf2ccf2dbf 122 return e;
Christopher Haster 0:b1b901ae3696 123 }
Christopher Haster 0:b1b901ae3696 124
Christopher Haster 14:5abf2ccf2dbf 125 void EventQueue::dealloc(struct event *e) {
Christopher Haster 14:5abf2ccf2dbf 126 uint32_t primask = __get_PRIMASK();
Christopher Haster 14:5abf2ccf2dbf 127 __disable_irq();
Christopher Haster 14:5abf2ccf2dbf 128
Christopher Haster 14:5abf2ccf2dbf 129 e->next = _free;
Christopher Haster 14:5abf2ccf2dbf 130 _free = e;
Christopher Haster 14:5abf2ccf2dbf 131
Christopher Haster 14:5abf2ccf2dbf 132 __set_PRIMASK(primask);
Christopher Haster 14:5abf2ccf2dbf 133
Christopher Haster 14:5abf2ccf2dbf 134 }
Christopher Haster 14:5abf2ccf2dbf 135