Move swaybar's event loop to common directory and refactor

* The loop functions are now prefixed with `loop_`.
* It is now easy to add timers to the loop.
* Timers are implemented using pollfd and timerfd, rather than manually
checking them when any other event happens to arrive.

4 files changed, 12 insertions, 166 deletions

diff --git a/swaybar/bar.c b/swaybar/bar.c
index 9f72c94c..8e89c9a8 100644
--- a/swaybar/bar.c
+++ b/swaybar/bar.c
@@ -18,7 +18,6 @@
 #endif
 #include "swaybar/bar.h"
 #include "swaybar/config.h"
-#include "swaybar/event_loop.h"
 #include "swaybar/i3bar.h"
 #include "swaybar/ipc.h"
 #include "swaybar/status_line.h"
@@ -26,6 +25,7 @@
 #include "ipc-client.h"
 #include "list.h"
 #include "log.h"
+#include "loop.h"
 #include "pool-buffer.h"
 #include "wlr-layer-shell-unstable-v1-client-protocol.h"
 #include "xdg-output-unstable-v1-client-protocol.h"
@@ -573,7 +573,7 @@ static void set_bar_dirty(struct swaybar *bar) {
 
 bool bar_setup(struct swaybar *bar, const char *socket_path) {
         bar_init(bar);
-        init_event_loop();
+        bar->eventloop = loop_create();
 
         bar->ipc_socketfd = ipc_open_socket(socket_path);
         bar->ipc_event_socketfd = ipc_open_socket(socket_path);
@@ -582,6 +582,7 @@ bool bar_setup(struct swaybar *bar, const char *socket_path) {
         }
         if (bar->config->status_command) {
                 bar->status = status_line_init(bar->config->status_command);
+                bar->status->bar = bar;
         }
 
         bar->display = wl_display_connect(NULL);
@@ -646,21 +647,23 @@ static void status_in(int fd, short mask, void *data) {
         if (mask & (POLLHUP | POLLERR)) {
                 status_error(bar->status, "[error reading from status command]");
                 set_bar_dirty(bar);
-                remove_event(fd);
+                loop_remove_event(bar->eventloop, bar->status_event);
         } else if (status_handle_readable(bar->status)) {
                 set_bar_dirty(bar);
         }
 }
 
 void bar_run(struct swaybar *bar) {
-        add_event(wl_display_get_fd(bar->display), POLLIN, display_in, bar);
-        add_event(bar->ipc_event_socketfd, POLLIN, ipc_in, bar);
+        loop_add_fd(bar->eventloop, wl_display_get_fd(bar->display), POLLIN,
+                        display_in, bar);
+        loop_add_fd(bar->eventloop, bar->ipc_event_socketfd, POLLIN, ipc_in, bar);
         if (bar->status) {
-                add_event(bar->status->read_fd, POLLIN, status_in, bar);
+                bar->status_event = loop_add_fd(
+                                bar->eventloop, bar->status->read_fd, POLLIN, status_in, bar);
         }
         while (1) {
                 wl_display_flush(bar->display);
-                event_loop_poll();
+                loop_poll(bar->eventloop);
         }
 }
 
diff --git a/swaybar/event_loop.c b/swaybar/event_loop.c
deleted file mode 100644
index 686b9962..00000000
--- a/swaybar/event_loop.c
+++ /dev/null
@@ -1,156 +0,0 @@
-#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(void) {
-        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(void) {
-        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();
-}
diff --git a/swaybar/meson.build b/swaybar/meson.build
index 7a02a33f..0c116172 100644
--- a/swaybar/meson.build
+++ b/swaybar/meson.build
@@ -2,7 +2,6 @@ executable(
         'swaybar', [
                 'bar.c',
                 'config.c',
-                'event_loop.c',
                 'i3bar.c',
                 'ipc.c',
                 'main.c',
diff --git a/swaybar/status_line.c b/swaybar/status_line.c
index 000609ce..3f7a386f 100644
--- a/swaybar/status_line.c
+++ b/swaybar/status_line.c
@@ -7,16 +7,16 @@
 #include <stdio.h>
 #include <unistd.h>
 #include <wlr/util/log.h>
+#include "loop.h"
 #include "swaybar/bar.h"
 #include "swaybar/config.h"
 #include "swaybar/i3bar.h"
-#include "swaybar/event_loop.h"
 #include "swaybar/status_line.h"
 #include "readline.h"
 
 static void status_line_close_fds(struct status_line *status) {
         if (status->read_fd != -1) {
-                remove_event(status->read_fd);
+                loop_remove_event(status->bar->eventloop, status->bar->status_event);
                 close(status->read_fd);
                 status->read_fd = -1;
         }