Merge pull request #1584 from 4e554c4c/no_more_hups

Handle swaybar status line errors

5 files changed, 94 insertions, 12 deletions

diff --git a/include/swaybar/event_loop.h b/include/swaybar/event_loop.h
index a0cde07f..d5089262 100644
--- a/include/swaybar/event_loop.h
+++ b/include/swaybar/event_loop.h
@@ -13,11 +13,11 @@ 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);
+// Remove the given event from the event loop
+void remove_event(int fd);
 
-// Returns false if nothing exists, true otherwise
-bool remove_timer(timer_t timer);
+// Remove the given timer from the event loop
+void remove_timer(timer_t timer);
 
 // Blocks and returns after sending callbacks
 void event_loop_poll();
diff --git a/include/swaybar/status_line.h b/include/swaybar/status_line.h
index 0664ddee..3ec0fcd0 100644
--- a/include/swaybar/status_line.h
+++ b/include/swaybar/status_line.h
@@ -49,6 +49,12 @@ struct status_line *init_status_line();
 bool handle_status_line(struct bar *bar);
 
 /**
+ * This should be called if statusline input cannot be accessed.
+ * It will set an error statusline instead of using the status command
+ */
+void handle_status_hup(struct status_line *status);
+
+/**
  * Handle mouse clicks.
  */
 bool status_line_mouse_event(struct bar *bar, int x, int y, uint32_t button);
diff --git a/swaybar/bar.c b/swaybar/bar.c
index 6db556a8..deddf971 100644
--- a/swaybar/bar.c
+++ b/swaybar/bar.c
@@ -274,6 +274,14 @@ static void respond_ipc(int fd, short mask, void *_bar) {
 
 static void respond_command(int fd, short mask, void *_bar) {
         struct bar *bar = (struct bar *)_bar;
+        if (mask & POLLHUP) {
+                // Something's wrong with the command
+                handle_status_hup(bar->status);
+                dirty = true;
+                // We will stop watching the status line so swaybar won't
+                // flood the CPU with its HUPs
+                remove_event(fd);
+        }
         dirty = handle_status_line(bar);
 }
 
@@ -286,7 +294,7 @@ static void respond_output(int fd, short mask, void *_output) {
 
 void bar_run(struct bar *bar) {
         add_event(bar->ipc_event_socketfd, POLLIN, respond_ipc, bar);
-        add_event(bar->status_read_fd, POLLIN, respond_command, bar);
+        add_event(bar->status_read_fd, POLLIN | POLLHUP, respond_command, bar);
 
         int i;
         for (i = 0; i < bar->outputs->length; ++i) {
diff --git a/swaybar/event_loop.c b/swaybar/event_loop.c
index 0d1be1da..bde8203f 100644
--- a/swaybar/event_loop.c
+++ b/swaybar/event_loop.c
@@ -20,6 +20,19 @@ struct timer_item {
         void *data;
 };
 
+enum state_item_flags {
+        ITEM_IS_FD,
+        ITEM_IS_TIMER,
+};
+
+struct state_item {
+        enum state_item_flags flags;
+        union {
+                int fd;
+                timer_t timer;
+        } inner;
+};
+
 static struct {
         // The order of each must be kept consistent
         struct {   /* pollfd array */
@@ -31,6 +44,9 @@ static struct {
 
         // Timer list
         list_t *timers;
+
+        // List of state changes at the end of each iteration
+        list_t *state;
 } event_loop;
 
 void add_timer(timer_t timer,
@@ -72,7 +88,7 @@ void add_event(int fd, short mask,
         return;
 }
 
-bool remove_event(int fd) {
+static void _remove_event(int fd) {
         int index = -1;
         for (int i = 0; i < event_loop.fds.length; ++i) {
                 if (event_loop.fds.items[i].fd == fd) {
@@ -87,12 +103,16 @@ bool remove_event(int fd) {
                                 sizeof(struct pollfd) * event_loop.fds.length - index);
 
                 list_del(event_loop.items, index);
-                return true;
-        } else {
-                return false;
         }
 }
 
+void remove_event(int fd) {
+        struct state_item *item = malloc(sizeof(struct state_item));
+        item->flags = ITEM_IS_FD;
+        item->inner.fd = fd;
+        list_add(event_loop.state, item);
+}
+
 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;
@@ -102,14 +122,19 @@ static int timer_item_timer_cmp(const void *_timer_item, const void *_timer) {
                 return -1;
         }
 }
-bool remove_timer(timer_t timer) {
+static void _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 remove_timer(timer_t timer) {
+        struct state_item *item = malloc(sizeof(struct state_item));
+        item->flags = ITEM_IS_TIMER;
+        item->inner.timer = timer;
+        list_add(event_loop.state, item);
 }
 
 void event_loop_poll() {
@@ -133,6 +158,19 @@ void event_loop_poll() {
                         item->cb(item->timer, item->data);
                 }
         }
+
+        // Remove all requested items from the event loop. We can't do this
+        // during normal operation, as it will cause race conditions.
+        for (int i = 0; i < event_loop.state->length; ++i) {
+                struct state_item *item = event_loop.state->items[i];
+                if (item->flags == ITEM_IS_FD) {
+                        _remove_event(item->inner.fd);
+                } else {
+                        _remove_timer(item->inner.timer);
+                }
+                free(item);
+        }
+        event_loop.state->length = 0; // reset state list
 }
 
 void init_event_loop() {
@@ -141,4 +179,5 @@ void init_event_loop() {
         event_loop.fds.items = malloc(event_loop.fds.capacity * sizeof(struct pollfd));
         event_loop.items = create_list();
         event_loop.timers = create_list();
+        event_loop.state = create_list();
 }
diff --git a/swaybar/status_line.c b/swaybar/status_line.c
index e3cc0bf4..bbb798f1 100644
--- a/swaybar/status_line.c
+++ b/swaybar/status_line.c
@@ -511,6 +511,35 @@ bool handle_status_line(struct bar *bar) {
         return dirty;
 }
 
+void handle_status_hup(struct status_line *line) {
+        // This is somewhat hacky, but free all previous status line state and
+        // then create a status block that displays an error string. This is so
+        // we can have pretty error colors.
+        sway_log(L_ERROR, "Replacing statusline with error string, as the status command has failed");
+        if (line->block_line) {
+                list_foreach(line->block_line, free_status_block);
+                list_free(line->block_line);
+        }
+        line->block_line = create_list();
+        struct status_block *new = calloc(1, sizeof(struct status_block));
+        new->full_text = strdup("ERROR: swaybar cannot access the statusline");
+        new->color = 0xff0000ff;
+        new->min_width = 0;
+        new->align = strdup("left");
+        new->markup = false;
+        new->separator = true;
+        new->separator_block_width = 9;
+        new->background = 0x0;
+        new->border = 0x0;
+        new->border_top = 1;
+        new->border_bottom = 1;
+        new->border_left = 1;
+        new->border_right = 1;
+        list_add(line->block_line, new);
+
+        line->protocol = I3BAR;
+}
+
 struct status_line *init_status_line() {
         struct status_line *line = malloc(sizeof(struct status_line));
         line->block_line = create_list();