backends/drm: Change the base class of DrmLeaseOutput

At the moment, the DrmLeaseOutput class inherits from the
KWaylandServer::DrmLeaseConnectionV1Interface class. While this works,
it's not a future-proof design. For example, kwin could also lease its
"desktop" outputs in order to let another wayland compositor run
alongside it.

Also, it's a good practice to prefer composition over inheritance.

src/backends/drm/drm_gpu.cpp

@@ -616,10 +616,13 @@ void DrmGpu::handleLeaseRequest(KWaylandServer::DrmLeaseV1Interface *leaseReques
 {
     QVector<uint32_t> objects;
     QVector<DrmLeaseOutput *> outputs;
-    const auto conns = leaseRequest->connectors();
-    for (const auto &connector : conns) {
-        auto output = qobject_cast<DrmLeaseOutput *>(connector);
-        if (m_leaseOutputs.contains(output) && !output->lease()) {
+
+    const auto connectors = leaseRequest->connectors();
+    for (KWaylandServer::DrmLeaseConnectorV1Interface *connector : connectors) {
+        if (DrmLeaseOutput *output = findLeaseOutput(connector->id())) {
+            if (output->lease()) {
+                continue; // already leased
+            }
             if (!output->addLeaseObjects(objects)) {
                 leaseRequest->deny();
                 return;
@@ -627,6 +630,7 @@ void DrmGpu::handleLeaseRequest(KWaylandServer::DrmLeaseV1Interface *leaseReques
             outputs << output;
         }
     }
+
     uint32_t lesseeId;
     int fd = drmModeCreateLease(m_fd, objects.constData(), objects.count(), 0, &lesseeId);
     if (fd < 0) {
@@ -650,10 +654,9 @@ void DrmGpu::handleLeaseRequest(KWaylandServer::DrmLeaseV1Interface *leaseReques
 
 void DrmGpu::handleLeaseRevoked(KWaylandServer::DrmLeaseV1Interface *lease)
 {
-    const auto conns = lease->connectors();
-    for (const auto &connector : conns) {
-        auto output = qobject_cast<DrmLeaseOutput *>(connector);
-        if (m_leaseOutputs.contains(output)) {
+    const auto connectors = lease->connectors();
+    for (KWaylandServer::DrmLeaseConnectorV1Interface *connector : connectors) {
+        if (DrmLeaseOutput *output = findLeaseOutput(connector->id())) {
             output->leaseEnded();
         }
     }

src/backends/drm/drm_lease_output.cpp

@@ -24,14 +24,16 @@ namespace KWin
 {
 
 DrmLeaseOutput::DrmLeaseOutput(DrmPipeline *pipeline, KWaylandServer::DrmLeaseDeviceV1Interface *leaseDevice)
-    : KWaylandServer::DrmLeaseConnectorV1Interface(
-        leaseDevice,
-        pipeline->connector()->id(),
-        pipeline->connector()->modelName(),
-        QStringLiteral("%1 %2").arg(pipeline->connector()->edid()->manufacturerString(), pipeline->connector()->modelName()))
-    , m_pipeline(pipeline)
+    : m_pipeline(pipeline)
 {
-    qCDebug(KWIN_DRM) << "offering connector" << m_pipeline->connector()->id() << "for lease";
+    const DrmConnector *connector = pipeline->connector();
+    qCDebug(KWIN_DRM) << "offering connector" << connector->id() << "for lease";
+
+    m_offer = std::make_unique<KWaylandServer::DrmLeaseConnectorV1Interface>(
+        leaseDevice,
+        connector->id(),
+        connector->modelName(),
+        QStringLiteral("%1 %2").arg(connector->edid()->manufacturerString(), connector->modelName()));
 }
 
 DrmLeaseOutput::~DrmLeaseOutput()

src/backends/drm/drm_lease_output.h

@@ -24,12 +24,11 @@ class DrmPipeline;
  * that is not used directly by the compositor but is instead leased out to
  * applications (usually VR compositors) that drive the output themselves
  */
-class DrmLeaseOutput : public KWaylandServer::DrmLeaseConnectorV1Interface
+class DrmLeaseOutput
 {
-    Q_OBJECT
 public:
     DrmLeaseOutput(DrmPipeline *pipeline, KWaylandServer::DrmLeaseDeviceV1Interface *leaseDevice);
-    ~DrmLeaseOutput() override;
+    ~DrmLeaseOutput();
 
     bool addLeaseObjects(QVector<uint32_t> &objectList);
     void leased(KWaylandServer::DrmLeaseV1Interface *lease);
@@ -40,6 +39,7 @@ public:
 
 private:
     DrmPipeline *m_pipeline;
+    std::unique_ptr<KWaylandServer::DrmLeaseConnectorV1Interface> m_offer;
     KWaylandServer::DrmLeaseV1Interface *m_lease = nullptr;
 };
 

src/wayland/drmleasedevice_v1_interface.cpp

@@ -182,6 +182,11 @@ DrmLeaseConnectorV1Interface::~DrmLeaseConnectorV1Interface()
     }
 }
 
+uint32_t DrmLeaseConnectorV1Interface::id() const
+{
+    return d->connectorId;
+}
+
 DrmLeaseConnectorV1Interface *DrmLeaseConnectorV1Interface::get(wl_resource *resource)
 {
     if (auto connectorPrivate = resource_cast<DrmLeaseConnectorV1InterfacePrivate *>(resource)) {

src/wayland/drmleasedevice_v1_interface.h

@@ -72,6 +72,8 @@ public:
     explicit DrmLeaseConnectorV1Interface(DrmLeaseDeviceV1Interface *leaseDevice, uint32_t id, const QString &name, const QString &description);
     ~DrmLeaseConnectorV1Interface() override;
 
+    uint32_t id() const;
+
     static DrmLeaseConnectorV1Interface *get(wl_resource *resource);
 
 private: