2 files changed, 180 insertions, 0 deletions
diff --git a/common/loop.c b/common/loop.c
new file mode 100644
index 00000000..1b174967
--- /dev/null
+++ b/common/loop.c
@@ -0,0 +1,179 @@
+#include <limits.h>
+#include <string.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <poll.h>
+#include <time.h>
+#include <unistd.h>
+#include "list.h"
+#include "log.h"
+#include "loop.h"
+
+struct loop_fd_event {
+	void (*callback)(int fd, short mask, void *data);
+	void *data;
+};
+
+struct loop_timer {
+	void (*callback)(void *data);
+	void *data;
+	struct timespec expiry;
+};
+
+struct loop {
+	struct pollfd *fds;
+	int fd_length;
+	int fd_capacity;
+
+	list_t *fd_events; // struct loop_fd_event
+	list_t *timers; // struct loop_timer
+};
+
+struct loop *loop_create(void) {
+	struct loop *loop = calloc(1, sizeof(struct loop));
+	if (!loop) {
+		wlr_log(WLR_ERROR, "Unable to allocate memory for loop");
+		return NULL;
+	}
+	loop->fd_capacity = 10;
+	loop->fds = malloc(sizeof(struct pollfd) * loop->fd_capacity);
+	loop->fd_events = create_list();
+	loop->timers = create_list();
+	return loop;
+}
+
+void loop_destroy(struct loop *loop) {
+	list_foreach(loop->fd_events, free);
+	list_foreach(loop->timers, free);
+	list_free(loop->fd_events);
+	list_free(loop->timers);
+	free(loop->fds);
+	free(loop);
+}
+
+void loop_poll(struct loop *loop) {
+	// Calculate next timer in ms
+	int ms = INT_MAX;
+	if (loop->timers->length) {
+		struct timespec now;
+		clock_gettime(CLOCK_MONOTONIC, &now);
+		for (int i = 0; i < loop->timers->length; ++i) {
+			struct loop_timer *timer = loop->timers->items[i];
+			int timer_ms = (timer->expiry.tv_sec - now.tv_sec) * 1000;
+			timer_ms += (timer->expiry.tv_nsec - now.tv_nsec) / 1000000;
+			if (timer_ms < ms) {
+				ms = timer_ms;
+			}
+		}
+	}
+	if (ms < 0) {
+		ms = 0;
+	}
+
+	poll(loop->fds, loop->fd_length, ms);
+
+	// Dispatch fds
+	for (int i = 0; i < loop->fd_length; ++i) {
+		struct pollfd pfd = loop->fds[i];
+		struct loop_fd_event *event = loop->fd_events->items[i];
+
+		// Always send these events
+		unsigned events = pfd.events | POLLHUP | POLLERR;
+
+		if (pfd.revents & events) {
+			event->callback(pfd.fd, pfd.revents, event->data);
+		}
+	}
+
+	// Dispatch timers
+	if (loop->timers->length) {
+		struct timespec now;
+		clock_gettime(CLOCK_MONOTONIC, &now);
+		for (int i = 0; i < loop->timers->length; ++i) {
+			struct loop_timer *timer = loop->timers->items[i];
+			bool expired = timer->expiry.tv_sec < now.tv_sec ||
+				(timer->expiry.tv_sec == now.tv_sec &&
+				 timer->expiry.tv_nsec < now.tv_nsec);
+			if (expired) {
+				timer->callback(timer->data);
+				loop_remove_timer(loop, timer);
+				--i;
+			}
+		}
+	}
+}
+
+void loop_add_fd(struct loop *loop, int fd, short mask,
+		void (*callback)(int fd, short mask, void *data), void *data) {
+	struct loop_fd_event *event = calloc(1, sizeof(struct loop_fd_event));
+	if (!event) {
+		wlr_log(WLR_ERROR, "Unable to allocate memory for event");
+		return;
+	}
+	event->callback = callback;
+	event->data = data;
+	list_add(loop->fd_events, event);
+
+	struct pollfd pfd = {fd, mask, 0};
+
+	if (loop->fd_length == loop->fd_capacity) {
+		loop->fd_capacity += 10;
+		loop->fds = realloc(loop->fds,
+				sizeof(struct pollfd) * loop->fd_capacity);
+	}
+
+	loop->fds[loop->fd_length++] = pfd;
+}
+
+struct loop_timer *loop_add_timer(struct loop *loop, int ms,
+		void (*callback)(void *data), void *data) {
+	struct loop_timer *timer = calloc(1, sizeof(struct loop_timer));
+	if (!timer) {
+		wlr_log(WLR_ERROR, "Unable to allocate memory for timer");
+		return NULL;
+	}
+	timer->callback = callback;
+	timer->data = data;
+
+	clock_gettime(CLOCK_MONOTONIC, &timer->expiry);
+	timer->expiry.tv_sec += ms / 1000;
+
+	long int nsec = (ms % 1000) * 1000000;
+	if (timer->expiry.tv_nsec + nsec >= 1000000000) {
+		timer->expiry.tv_sec++;
+		nsec -= 1000000000;
+	}
+	timer->expiry.tv_nsec += nsec;
+
+	list_add(loop->timers, timer);
+
+	return timer;
+}
+
+bool loop_remove_fd(struct loop *loop, int fd) {
+	for (int i = 0; i < loop->fd_length; ++i) {
+		if (loop->fds[i].fd == fd) {
+			free(loop->fd_events->items[i]);
+			list_del(loop->fd_events, i);
+
+			loop->fd_length--;
+			memmove(&loop->fds[i], &loop->fds[i + 1],
+					sizeof(struct pollfd) * (loop->fd_length - i));
+
+			return true;
+		}
+	}
+	return false;
+}
+
+bool loop_remove_timer(struct loop *loop, struct loop_timer *timer) {
+	for (int i = 0; i < loop->timers->length; ++i) {
+		if (loop->timers->items[i] == timer) {
+			list_del(loop->timers, i);
+			free(timer);
+			return true;
+		}
+	}
+	return false;
+}
diff --git a/common/meson.build b/common/meson.build
index 44a29508..224a9c3f 100644
--- a/common/meson.build
+++ b/common/meson.build
@@ -5,6 +5,7 @@ lib_sway_common = static_library(
 		'cairo.c',
 		'ipc-client.c',
 		'log.c',
+		'loop.c',
 		'list.c',
 		'pango.c',
 		'readline.c',