From fb1414a0524d996f912a82abaf2896754afd663a Mon Sep 17 00:00:00 2001
From: Isaac Freund <ifreund@ifreund.xyz>
Date: Fri, 17 Apr 2020 16:00:05 +0200
Subject: [PATCH] Clean up listener handling for layer surfaces

---
 src/layer_surface.zig | 72 +++++++++++++++++++++++++++++--------------
 src/render.zig        |  3 ++
 2 files changed, 52 insertions(+), 23 deletions(-)

diff --git a/src/layer_surface.zig b/src/layer_surface.zig
index 1d7b2f8..b9825e7 100644
--- a/src/layer_surface.zig
+++ b/src/layer_surface.zig
@@ -11,12 +11,18 @@ pub const LayerSurface = struct {
     output: *Output,
     wlr_layer_surface: *c.wlr_layer_surface_v1,
 
+    /// True if the layer surface is currently mapped
+    mapped: bool,
+
     box: Box,
     layer: c.zwlr_layer_shell_v1_layer,
 
+    // Listeners active the entire lifetime of the layser surface
+    listen_destroy: c.wl_listener,
     listen_map: c.wl_listener,
     listen_unmap: c.wl_listener,
-    listen_destroy: c.wl_listener,
+
+    // Listeners only active while the layer surface is mapped
     listen_commit: c.wl_listener,
     listen_new_popup: c.wl_listener,
 
@@ -29,23 +35,20 @@ pub const LayerSurface = struct {
         self.output = output;
         self.wlr_layer_surface = wlr_layer_surface;
 
+        self.mapped = false;
+
         self.box = undefined;
         self.layer = layer;
 
+        // Set up listeners that are active for the entire lifetime of the layer surface
+        self.listen_destroy.notify = handleDestroy;
+        c.wl_signal_add(&self.wlr_layer_surface.events.destroy, &self.listen_destroy);
+
         self.listen_map.notify = handleMap;
         c.wl_signal_add(&self.wlr_layer_surface.events.map, &self.listen_map);
 
         self.listen_unmap.notify = handleUnmap;
         c.wl_signal_add(&self.wlr_layer_surface.events.unmap, &self.listen_unmap);
-
-        self.listen_destroy.notify = handleDestroy;
-        c.wl_signal_add(&self.wlr_layer_surface.events.destroy, &self.listen_destroy);
-
-        self.listen_commit.notify = handleCommit;
-        c.wl_signal_add(&self.wlr_layer_surface.surface.*.events.commit, &self.listen_commit);
-
-        self.listen_new_popup.notify = handleNewPopup;
-        c.wl_signal_add(&self.wlr_layer_surface.events.new_popup, &self.listen_new_popup);
     }
 
     /// Send a configure event to the client with the dimensions of the current box
@@ -53,19 +56,6 @@ pub const LayerSurface = struct {
         c.wlr_layer_surface_v1_configure(self.wlr_layer_surface, self.box.width, self.box.height);
     }
 
-    fn handleMap(listener: ?*c.wl_listener, data: ?*c_void) callconv(.C) void {
-        const layer_surface = @fieldParentPtr(LayerSurface, "listen_map", listener.?);
-        c.wlr_surface_send_enter(
-            layer_surface.wlr_layer_surface.surface,
-            layer_surface.wlr_layer_surface.output,
-        );
-        layer_surface.output.arrangeLayers();
-    }
-
-    fn handleUnmap(listener: ?*c.wl_listener, data: ?*c_void) callconv(.C) void {
-        const layer_surface = @fieldParentPtr(LayerSurface, "listen_unmap", listener.?);
-    }
-
     fn handleDestroy(listener: ?*c.wl_listener, data: ?*c_void) callconv(.C) void {
         const layer_surface = @fieldParentPtr(LayerSurface, "listen_destroy", listener.?);
         Log.Debug.log("Layer surface '{}' destroyed", .{layer_surface.wlr_layer_surface.namespace});
@@ -75,6 +65,42 @@ pub const LayerSurface = struct {
         layer_surface.output.root.server.allocator.destroy(node);
 
         layer_surface.output.arrangeLayers();
+
+        // Remove listeners active the entire lifetime of the layer surface
+        c.wl_list_remove(&layer_surface.listen_destroy);
+        c.wl_list_remove(&layer_surface.listen_map);
+        c.wl_list_remove(&layer_surface.listen_unmap);
+    }
+
+    fn handleMap(listener: ?*c.wl_listener, data: ?*c_void) callconv(.C) void {
+        const layer_surface = @fieldParentPtr(LayerSurface, "listen_map", listener.?);
+        const wlr_layer_surface = layer_surface.wlr_layer_surface;
+
+        layer_surface.mapped = true;
+
+        // Add listeners that are only active while mapped
+        layer_surface.listen_commit.notify = handleCommit;
+        c.wl_signal_add(&wlr_layer_surface.surface.*.events.commit, &layer_surface.listen_commit);
+
+        layer_surface.listen_new_popup.notify = handleNewPopup;
+        c.wl_signal_add(&wlr_layer_surface.events.new_popup, &layer_surface.listen_new_popup);
+
+        c.wlr_surface_send_enter(
+            wlr_layer_surface.surface,
+            wlr_layer_surface.output,
+        );
+
+        layer_surface.output.arrangeLayers();
+    }
+
+    fn handleUnmap(listener: ?*c.wl_listener, data: ?*c_void) callconv(.C) void {
+        const layer_surface = @fieldParentPtr(LayerSurface, "listen_unmap", listener.?);
+
+        layer_surface.mapped = false;
+
+        // remove listeners only active while the layer surface is mapped
+        c.wl_list_remove(&layer_surface.listen_commit.link);
+        c.wl_list_remove(&layer_surface.listen_new_popup.link);
     }
 
     fn handleCommit(listener: ?*c.wl_listener, data: ?*c_void) callconv(.C) void {
diff --git a/src/render.zig b/src/render.zig
index 6a7f2b4..e9c6089 100644
--- a/src/render.zig
+++ b/src/render.zig
@@ -73,6 +73,9 @@ fn renderLayer(output: Output, layer: std.TailQueue(LayerSurface), now: *c.struc
     var it = layer.first;
     while (it) |node| : (it = node.next) {
         const layer_surface = &node.data;
+        if (!layer_surface.mapped) {
+            continue;
+        }
         var rdata = LayerSurfaceRenderData{
             .output = output.wlr_output,
             .renderer = output.root.server.wlr_renderer,