Drop "sub-feedback" concept in PresentationFeedback

This gets rid of the container feedback to simplify presentation
feedback organization.

src/core/renderbackend.cpp

@@ -83,18 +83,6 @@ std::unique_ptr<SurfaceTexture> RenderBackend::createSurfaceTextureWayland(Surfa
     return nullptr;
 }
 
-PresentationFeedback::PresentationFeedback(std::vector<std::unique_ptr<PresentationFeedback>> &&feedbacks)
-    : m_subFeedbacks(std::move(feedbacks))
-{
-}
-
-void PresentationFeedback::presented(std::chrono::nanoseconds refreshCycleDuration, std::chrono::nanoseconds timestamp, PresentationMode mode)
-{
-    for (const auto &feedback : m_subFeedbacks) {
-        feedback->presented(refreshCycleDuration, timestamp, mode);
-    }
-}
-
 } // namespace KWin
 
 #include "moc_renderbackend.cpp"

src/core/renderbackend.h

@@ -31,15 +31,11 @@ class PresentationFeedback
 {
 public:
     explicit PresentationFeedback() = default;
-    explicit PresentationFeedback(std::vector<std::unique_ptr<PresentationFeedback>> &&feedbacks);
     PresentationFeedback(const PresentationFeedback &copy) = delete;
     PresentationFeedback(PresentationFeedback &&move) = default;
     virtual ~PresentationFeedback() = default;
 
-    virtual void presented(std::chrono::nanoseconds refreshCycleDuration, std::chrono::nanoseconds timestamp, PresentationMode mode);
-
-private:
-    std::vector<std::unique_ptr<PresentationFeedback>> m_subFeedbacks;
+    virtual void presented(std::chrono::nanoseconds refreshCycleDuration, std::chrono::nanoseconds timestamp, PresentationMode mode) = 0;
 };
 
 class KWIN_EXPORT OutputFrame

src/wayland/presentationtime.cpp

@@ -32,29 +32,37 @@ void PresentationTime::wp_presentation_feedback(Resource *resource, wl_resource
 {
     SurfaceInterface *surf = SurfaceInterface::get(surface);
     SurfaceInterfacePrivate *surfPriv = SurfaceInterfacePrivate::get(surf);
-    surfPriv->pending->presentationFeedbacks.push_back(std::make_unique<PresentationTimeFeedback>(surf, resource->client(), callback));
+
+    auto &feedback = surfPriv->pending->presentationFeedback;
+    if (!feedback) {
+        feedback = std::make_unique<PresentationTimeFeedback>();
+    }
+
+    wl_resource *feedbackResource = wl_resource_create(resource->client(), &wp_presentation_feedback_interface, resource->version(), callback);
+    wl_resource_set_implementation(feedbackResource, nullptr, nullptr, [](wl_resource *resource) {
+        wl_list_remove(wl_resource_get_link(resource));
+    });
+
+    wl_list_insert(feedback->resources.prev, wl_resource_get_link(feedbackResource));
 }
 
-PresentationTimeFeedback::PresentationTimeFeedback(SurfaceInterface *surface, wl_client *client, uint32_t id)
-    : QtWaylandServer::wp_presentation_feedback(client, id, 1)
-    , m_surface(surface)
+PresentationTimeFeedback::PresentationTimeFeedback()
 {
+    wl_list_init(&resources);
 }
 
 PresentationTimeFeedback::~PresentationTimeFeedback()
 {
-    if (m_destroyed) {
-        return;
+    wl_resource *resource;
+    wl_resource *tmp;
+    wl_resource_for_each_safe (resource, tmp, &resources) {
+        wp_presentation_feedback_send_discarded(resource);
+        wl_resource_destroy(resource);
     }
-    send_discarded();
-    wl_resource_destroy(resource()->handle);
 }
 
 void PresentationTimeFeedback::presented(std::chrono::nanoseconds refreshCycleDuration, std::chrono::nanoseconds timestamp, PresentationMode mode)
 {
-    if (m_destroyed) {
-        return;
-    }
     const auto secs = std::chrono::duration_cast<std::chrono::seconds>(timestamp);
     const uint32_t tvSecHi = secs.count() >> 32;
     const uint32_t tvSecLo = secs.count() & 0xffffffff;
@@ -67,13 +75,11 @@ void PresentationTimeFeedback::presented(std::chrono::nanoseconds refreshCycleDu
         flags |= WP_PRESENTATION_FEEDBACK_KIND_VSYNC;
     }
 
-    send_presented(resource()->handle, tvSecHi, tvSecLo, tvNsec, refreshDuration, 0, 0, flags);
-    wl_resource_destroy(resource()->handle);
-    m_destroyed = true;
-}
-
-void PresentationTimeFeedback::wp_presentation_feedback_destroy_resource(Resource *resource)
-{
-    m_destroyed = true;
+    wl_resource *resource;
+    wl_resource *tmp;
+    wl_resource_for_each_safe (resource, tmp, &resources) {
+        wp_presentation_feedback_send_presented(resource, tvSecHi, tvSecLo, tvNsec, refreshDuration, 0, 0, flags);
+        wl_resource_destroy(resource);
+    }
 }
 }

src/wayland/presentationtime.h

@@ -30,19 +30,15 @@ private:
     void wp_presentation_feedback(Resource *resource, wl_resource *surface, uint32_t callback) override;
 };
 
-class PresentationTimeFeedback : public PresentationFeedback, public QtWaylandServer::wp_presentation_feedback
+class PresentationTimeFeedback : public PresentationFeedback
 {
 public:
-    explicit PresentationTimeFeedback(SurfaceInterface *surface, wl_client *client, uint32_t id);
+    PresentationTimeFeedback();
     ~PresentationTimeFeedback() override;
 
-    void presented(std::chrono::nanoseconds refreshCycleDuration, std::chrono::nanoseconds timestamp, PresentationMode mode) override;
-
-private:
-    void wp_presentation_feedback_destroy_resource(Resource *resource) override;
+    wl_list resources;
 
-    SurfaceInterface *const m_surface;
-    bool m_destroyed = false;
+    void presented(std::chrono::nanoseconds refreshCycleDuration, std::chrono::nanoseconds timestamp, PresentationMode mode) override;
 };
 
 }

src/wayland/surface.cpp

@@ -474,10 +474,7 @@ std::unique_ptr<PresentationFeedback> SurfaceInterface::takePresentationFeedback
     if (output && (!d->primaryOutput || d->primaryOutput->handle() != output)) {
         return nullptr;
     }
-    std::vector<std::unique_ptr<PresentationFeedback>> feedbacks;
-    std::move(d->current->presentationFeedbacks.begin(), d->current->presentationFeedbacks.end(), std::back_inserter(feedbacks));
-    d->current->presentationFeedbacks.clear();
-    return std::make_unique<PresentationFeedback>(std::move(feedbacks));
+    return std::move(d->current->presentationFeedback);
 }
 
 bool SurfaceInterface::hasFrameCallbacks() const
@@ -652,10 +649,9 @@ void SurfaceState::mergeInto(SurfaceState *target)
         target->colorDescription = colorDescription;
         target->colorDescriptionIsSet = true;
     }
-    for (auto &f : presentationFeedbacks) {
-        target->presentationFeedbacks.push_back(std::move(f));
+    if (presentationFeedback) {
+        target->presentationFeedback = std::move(presentationFeedback);
     }
-    presentationFeedbacks.clear();
 
     *this = SurfaceState{};
     serial = target->serial;
@@ -683,7 +679,7 @@ void SurfaceInterfacePrivate::applyState(SurfaceState *next)
     const QRegion oldInputRegion = inputRegion;
 
     if (!next->damage.isEmpty() || !next->bufferDamage.isEmpty()) {
-        current->presentationFeedbacks.clear();
+        current->presentationFeedback.reset();
     }
     next->mergeInto(current.get());
     bufferRef = current->buffer;

src/wayland/surface_p.h

@@ -69,7 +69,7 @@ struct SurfaceState
     ContentType contentType = ContentType::None;
     PresentationHint presentationHint = PresentationHint::VSync;
     ColorDescription colorDescription = ColorDescription::sRGB;
-    std::vector<std::unique_ptr<PresentationTimeFeedback>> presentationFeedbacks;
+    std::unique_ptr<PresentationTimeFeedback> presentationFeedback;
 
     struct
     {