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, 54 insertions, 26 deletions

diff --git a/include/loop.h b/include/loop.h
new file mode 100644
index 00000000..7c151785
--- /dev/null
+++ b/include/loop.h
@@ -0,0 +1,47 @@
+#ifndef _SWAY_LOOP_H
+#define _SWAY_LOOP_H
+#include <stdbool.h>
+
+/**
+ * This is an event loop system designed for sway clients, not sway itself.
+ *
+ * It uses pollfds to block on multiple file descriptors at once, and provides
+ * an easy way to set timers. Typically the Wayland display's fd will be one of
+ * the fds in the loop.
+ */
+
+struct loop;
+
+/**
+ * Create an event loop.
+ */
+struct loop *loop_create(void);
+
+/**
+ * Destroy the event loop (eg. on program termination).
+ */
+void loop_destroy(struct loop *loop);
+
+/**
+ * Poll the event loop. This will block until one of the fds has data.
+ */
+void loop_poll(struct loop *loop);
+
+/**
+ * Add an fd to the loop.
+ */
+struct loop_event *loop_add_fd(struct loop *loop, int fd, short mask,
+                void (*func)(int fd, short mask, void *data), void *data);
+
+/**
+ * Add a timer to the loop.
+ */
+struct loop_event *loop_add_timer(struct loop *loop, int ms,
+                void (*callback)(int fd, short mask, void *data), void *data);
+
+/**
+ * Remove an event from the loop.
+ */
+bool loop_remove_event(struct loop *loop, struct loop_event *event);
+
+#endif
diff --git a/include/swaybar/bar.h b/include/swaybar/bar.h
index 9ff3fe7b..d61da5dc 100644
--- a/include/swaybar/bar.h
+++ b/include/swaybar/bar.h
@@ -8,6 +8,8 @@
 struct swaybar_config;
 struct swaybar_output;
 struct swaybar_workspace;
+struct loop;
+struct loop_event;
 
 struct swaybar_pointer {
         struct wl_pointer *pointer;
@@ -66,6 +68,9 @@ struct swaybar {
         struct swaybar_pointer pointer;
         struct status_line *status;
 
+        struct loop *eventloop;
+        struct loop_event *status_event;
+
         int ipc_event_socketfd;
         int ipc_socketfd;
 
diff --git a/include/swaybar/event_loop.h b/include/swaybar/event_loop.h
deleted file mode 100644
index 47be5b79..00000000
--- a/include/swaybar/event_loop.h
+++ /dev/null
@@ -1,26 +0,0 @@
-#ifndef _SWAYBAR_EVENT_LOOP_H
-#define _SWAYBAR_EVENT_LOOP_H
-#include <stdbool.h>
-#include <time.h>
-
-void add_event(int fd, short mask,
-                void(*cb)(int fd, short mask, void *data),
-                void *data);
-
-// Not guaranteed to notify cb immediately
-void add_timer(timer_t timer,
-                void(*cb)(timer_t timer, void *data),
-                void *data);
-
-// Returns false if nothing exists, true otherwise
-bool remove_event(int fd);
-
-// Returns false if nothing exists, true otherwise
-bool remove_timer(timer_t timer);
-
-// Blocks and returns after sending callbacks
-void event_loop_poll(void);
-
-void init_event_loop(void);
-
-#endif
diff --git a/include/swaybar/status_line.h b/include/swaybar/status_line.h
index 5e7e8771..957a808e 100644
--- a/include/swaybar/status_line.h
+++ b/include/swaybar/status_line.h
@@ -14,6 +14,8 @@ enum status_protocol {
 };
 
 struct status_line {
+        struct swaybar *bar;
+
         pid_t pid;
         int read_fd, write_fd;
         FILE *read, *write;