api: add collect_output_nodes() and use this in plugins (#1978)

This function helps plugins to deal with always-on-top views.

plugins/common/wayfire/plugins/common/util.hpp

@@ -67,41 +67,38 @@ inline wf::geometry_t view_bounding_box_up_to(wayfire_view view,
  */
 inline wayfire_toplevel_view find_output_view_at(wf::output_t *output, const wf::pointf_t& coords)
 {
-    for (int i = int(wf::scene::layer::ALL_LAYERS) - 1; i >= 0; i--)
+    for (auto& output_node : wf::collect_output_nodes(wf::get_core().scene(), output))
     {
-        for (auto& output_node : wf::get_core().scene()->layers[i]->get_children())
+        auto as_output = std::dynamic_pointer_cast<scene::output_node_t>(output_node);
+        if (!as_output || (as_output->get_output() != output) || !as_output->is_enabled())
         {
-            auto as_output = std::dynamic_pointer_cast<scene::output_node_t>(output_node);
-            if (!as_output || (as_output->get_output() != output) || !as_output->is_enabled())
+            continue;
+        }
+
+        // We start the search directly from the output node's children. This is because the output nodes
+        // usually reject all queries outside of their current visible geometry, but we want to be able to
+        // query views from all workspaces, not just the current (and the only visible) one.
+        for (auto& ch : output_node->get_children())
+        {
+            if (!ch->is_enabled())
             {
                 continue;
             }
 
-            // We start the search directly from the output node's children. This is because the output nodes
-            // usually reject all queries outside of their current visible geometry, but we want to be able to
-            // query views from all workspaces, not just the current (and the only visible) one.
-            for (auto& ch : output_node->get_children())
-            {
-                if (!ch->is_enabled())
-                {
-                    continue;
-                }
-
-                auto isec = ch->find_node_at(coords);
-                auto node = isec ? isec->node.get() : nullptr;
+            auto isec = ch->find_node_at(coords);
+            auto node = isec ? isec->node.get() : nullptr;
 
-                if (auto view = wf::toplevel_cast(wf::node_to_view(node)))
+            if (auto view = wf::toplevel_cast(wf::node_to_view(node)))
+            {
+                if (view->get_wset() == output->wset())
                 {
-                    if (view->get_wset() == output->wset())
-                    {
-                        return view;
-                    }
+                    return view;
                 }
+            }
 
-                if (node)
-                {
-                    return nullptr;
-                }
+            if (node)
+            {
+                return nullptr;
             }
         }
     }

src/api/wayfire/output.hpp

@@ -205,6 +205,12 @@ class output_t : public wf::object_base_t, public wf::signal::provider_t
  * output is currently focused, otherwise NULL.
  */
 wayfire_view get_active_view_for_output(wf::output_t *output);
+
+/**
+ * Collect all nodes which belong to an output from the scenegraph.
+ */
+std::vector<std::shared_ptr<scene::output_node_t>> collect_output_nodes(
+    wf::scene::node_ptr root, wf::output_t *output);
 }
 
 #endif /* end of include guard: OUTPUT_HPP */

src/api/wayfire/plugin.hpp

@@ -108,7 +108,7 @@ class plugin_interface_t
 using wayfire_plugin_load_func = wf::plugin_interface_t * (*)();
 
 /** The version of Wayfire's API/ABI */
-constexpr uint32_t WAYFIRE_API_ABI_VERSION = 2023'10'21;
+constexpr uint32_t WAYFIRE_API_ABI_VERSION = 2023'10'25;
 
 /**
  * Each plugin must also provide a function which returns the Wayfire API/ABI

src/output/output.cpp

@@ -464,4 +464,36 @@ wayfire_view get_active_view_for_output(wf::output_t *output)
 
     return nullptr;
 }
+
+void collect_output_nodes_recursive(wf::scene::node_ptr root, wf::output_t *output,
+    std::vector<std::shared_ptr<scene::output_node_t>>& result)
+{
+    if (!root->is_enabled())
+    {
+        return;
+    }
+
+    if (auto output_node = std::dynamic_pointer_cast<scene::output_node_t>(root))
+    {
+        if (output_node->get_output() == output)
+        {
+            result.push_back(output_node);
+        }
+
+        return;
+    }
+
+    for (auto& ch : root->get_children())
+    {
+        collect_output_nodes_recursive(ch, output, result);
+    }
+}
+
+std::vector<std::shared_ptr<scene::output_node_t>> collect_output_nodes(
+    wf::scene::node_ptr root, wf::output_t *output)
+{
+    std::vector<std::shared_ptr<scene::output_node_t>> res;
+    collect_output_nodes_recursive(root, output, res);
+    return res;
+}
 } // namespace wf

src/output/workspace-stream.cpp

@@ -42,10 +42,9 @@ class workspace_stream_node_t::workspace_stream_instance_t : public scene::
             push_damage(damage);
         };
 
-        for (int layer = (int)scene::layer::ALL_LAYERS - 1; layer >= 0; layer--)
+        for (auto& output_node : wf::collect_output_nodes(wf::get_core().scene(), self->output))
         {
-            auto layer_root = self->output->node_for_layer((scene::layer)layer);
-            for (auto& ch : layer_root->get_children())
+            for (auto& ch : output_node->get_children())
             {
                 if (ch->is_enabled())
                 {