main: implement layer_surface::closed() event

Destroy the surface, and clear the ‘configured’ flag.

Note that we need to take care we don’t reference a destroyed output
object; if the compositor destroyed the output before calling the
closed() event, the ‘data’ argument will be an invalid pointer.

Since removing the output global _also_ destroys the surface, we can
handle this by looping all known output globals, and explicitly
destroy the surface if we find a match.

If we don’t find a match, that means the output has already been
destroyed, and we don’t have to do anything at all.

2 files changed, 33 insertions, 6 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 57de9c6..9fb490f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,10 @@
 ### Deprecated
 ### Removed
 ### Fixed
+
+* Respect the `layer_surface::closed()` event.
+
+
 ### Security
 ### Contributors
 
diff --git a/main.c b/main.c
index 7831455..03a7df6 100644
--- a/main.c
+++ b/main.c
@@ -140,8 +140,31 @@ layer_surface_configure(void *data, struct zwlr_layer_surface_v1 *surface,
 }
 
 static void
+output_layer_destroy(struct output *output)
+{
+    if (output->layer != NULL)
+        zwlr_layer_surface_v1_destroy(output->layer);
+    if (output->surf != NULL)
+        wl_surface_destroy(output->surf);
+
+    output->layer = NULL;
+    output->surf = NULL;
+    output->configured = false;
+}
+
+static void
 layer_surface_closed(void *data, struct zwlr_layer_surface_v1 *surface)
 {
+    struct output *output = data;
+
+    /* Don’t trust ‘output’ to be valid, in case compositor destroyed
+     * if before calling closed() */
+    tll_foreach(outputs, it) {
+        if (&it->item == output) {
+            output_layer_destroy(output);
+            break;
+        }
+    }
 }
 
 static const struct zwlr_layer_surface_v1_listener layer_surface_listener = {
@@ -152,14 +175,14 @@ static const struct zwlr_layer_surface_v1_listener layer_surface_listener = {
 static void
 output_destroy(struct output *output)
 {
-    free(output->make);
-    free(output->model);
-    if (output->layer != NULL)
-        zwlr_layer_surface_v1_destroy(output->layer);
-    if (output->surf != NULL)
-        wl_surface_destroy(output->surf);
+    output_layer_destroy(output);
+
     if (output->wl_output != NULL)
         wl_output_release(output->wl_output);
+    output->wl_output = NULL;
+
+    free(output->make);
+    free(output->model);
 }
 
 static void