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#include <stdint.h>
#include <stdbool.h>
#include <uv.h>
#include "os/event.h"
#include "os/input.h"
static uv_timer_t timer;
static uv_prepare_t timer_prepare;
static void timer_cb(uv_timer_t *handle, int);
static void timer_prepare_cb(uv_prepare_t *, int);
void event_init()
{
// Initialize input events
input_init();
// Timer to wake the event loop if a timeout argument is passed to
// `event_poll`
uv_timer_init(uv_default_loop(), &timer);
// This prepare handle that actually starts the timer
uv_prepare_init(uv_default_loop(), &timer_prepare);
}
// Wait for some event
bool event_poll(int32_t ms)
{
bool timed_out;
uv_run_mode run_mode = UV_RUN_ONCE;
if (input_ready()) {
// If there's a pending input event to be consumed, do it now
return true;
}
input_start();
timed_out = false;
if (ms > 0) {
// Timeout passed as argument to the timer
timer.data = &timed_out;
// We only start the timer after the loop is running, for that we
// use an prepare handle(pass the interval as data to it)
timer_prepare.data = &ms;
uv_prepare_start(&timer_prepare, timer_prepare_cb);
} else if (ms == 0) {
// For ms == 0, we need to do a non-blocking event poll by
// setting the run mode to UV_RUN_NOWAIT.
run_mode = UV_RUN_NOWAIT;
}
do {
// Run one event loop iteration, blocking for events if run_mode is
// UV_RUN_ONCE
uv_run(uv_default_loop(), run_mode);
} while (
// Continue running if ...
!input_ready() // ... we have no input
&& run_mode != UV_RUN_NOWAIT // ... ms != 0
&& !timed_out); // ... we didn't get a timeout
input_stop();
if (ms > 0) {
// Stop the timer
uv_timer_stop(&timer);
}
return input_ready();
}
// Set a flag in the `event_poll` loop for signaling of a timeout
static void timer_cb(uv_timer_t *handle, int status)
{
*((bool *)handle->data) = true;
}
static void timer_prepare_cb(uv_prepare_t *handle, int status)
{
uv_timer_start(&timer, timer_cb, *(uint32_t *)timer_prepare.data, 0);
uv_prepare_stop(&timer_prepare);
}
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