sway/swaybar/event_loop.c
Scott Anderson 9a3fb33e33 Change remove_event logic
We defer the removal of entries until after the poll loop has finished.
Otherwise we may end up adjusting the poll array while we're still
reading from it, causing us to skip events.
2018-04-21 14:38:34 +12:00

157 lines
3.5 KiB
C

#define _XOPEN_SOURCE 700
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <strings.h>
#include <poll.h>
#include <time.h>
#include "swaybar/event_loop.h"
#include "list.h"
struct event_item {
void (*cb)(int fd, short mask, void *data);
void *data;
};
struct timer_item {
timer_t timer;
void (*cb)(timer_t timer, void *data);
void *data;
};
static struct {
// The order of each must be kept consistent
struct { /* pollfd array */
struct pollfd *items;
int capacity;
int length;
} fds;
list_t *items; /* event_item list */
// Timer list
list_t *timers;
} event_loop;
void add_timer(timer_t timer,
void(*cb)(timer_t timer, void *data),
void *data) {
struct timer_item *item = malloc(sizeof(struct timer_item));
item->timer = timer;
item->cb = cb;
item->data = data;
list_add(event_loop.timers, item);
}
void add_event(int fd, short mask,
void(*cb)(int fd, short mask, void *data), void *data) {
struct pollfd pollfd = {
fd,
mask,
0,
};
// Resize
if (event_loop.fds.length == event_loop.fds.capacity) {
event_loop.fds.capacity += 10;
event_loop.fds.items = realloc(event_loop.fds.items,
sizeof(struct pollfd) * event_loop.fds.capacity);
}
event_loop.fds.items[event_loop.fds.length++] = pollfd;
struct event_item *item = malloc(sizeof(struct event_item));
item->cb = cb;
item->data = data;
list_add(event_loop.items, item);
return;
}
bool remove_event(int fd) {
/*
* Instead of removing events immediately, we mark them for deletion
* and clean them up later. This is so we can call remove_event inside
* an event callback safely.
*/
for (int i = 0; i < event_loop.fds.length; ++i) {
if (event_loop.fds.items[i].fd == fd) {
event_loop.fds.items[i].fd = -1;
return true;
}
}
return false;
}
static int timer_item_timer_cmp(const void *_timer_item, const void *_timer) {
const struct timer_item *timer_item = _timer_item;
const timer_t *timer = _timer;
if (timer_item->timer == *timer) {
return 0;
} else {
return -1;
}
}
bool remove_timer(timer_t timer) {
int index = list_seq_find(event_loop.timers, timer_item_timer_cmp, &timer);
if (index != -1) {
free(event_loop.timers->items[index]);
list_del(event_loop.timers, index);
return true;
}
return false;
}
void event_loop_poll() {
poll(event_loop.fds.items, event_loop.fds.length, -1);
for (int i = 0; i < event_loop.fds.length; ++i) {
struct pollfd pfd = event_loop.fds.items[i];
struct event_item *item = (struct event_item *)event_loop.items->items[i];
// Always send these events
unsigned events = pfd.events | POLLHUP | POLLERR;
if (pfd.revents & events) {
item->cb(pfd.fd, pfd.revents, item->data);
}
}
// Cleanup removed events
int end = 0;
int length = event_loop.fds.length;
for (int i = 0; i < length; ++i) {
if (event_loop.fds.items[i].fd == -1) {
free(event_loop.items->items[i]);
list_del(event_loop.items, i);
--event_loop.fds.length;
} else if (end != i) {
event_loop.fds.items[end++] = event_loop.fds.items[i];
} else {
end = i + 1;
}
}
// check timers
// not tested, but seems to work
for (int i = 0; i < event_loop.timers->length; ++i) {
struct timer_item *item = event_loop.timers->items[i];
int overrun = timer_getoverrun(item->timer);
if (overrun && overrun != -1) {
item->cb(item->timer, item->data);
}
}
}
void init_event_loop() {
event_loop.fds.length = 0;
event_loop.fds.capacity = 10;
event_loop.fds.items = malloc(
event_loop.fds.capacity * sizeof(struct pollfd));
event_loop.items = create_list();
event_loop.timers = create_list();
}