R8: finish app/ pure C ABI migration (P3-P9) and make OTIO required

- app/ no longer includes engine C++ headers nor holds engine C++ types:
  engine access goes through the oakengine C ABI plus C++ wrappers
  (oakutil/oaknode.h, oakutil/oakvideo.h) and app-local mirror types
  (tooltypes, trackreferencehandle, timelinecommonapp, keyframetypes,
  subtitleapp, serializedlayoutinfoapp, nodevaluehandle, sliderdisplaytypeapp)
- engine: new C ABI functions for block/track/clip/transition navigation
  and predicates, links, caches, waveform/playback, disk folder,
  sequence_track_list, node_free, footage_is_valid, block_get_track,
  get_brush; loadotio/saveotio ported to the current engine API
- OTIO is now a required dependency: CI and CD build it on every
  platform, FindOpenTimelineIO fixed for OTIO 0.16/0.19 (the old deps
  include requirement silently disabled OTIO everywhere), runtime
  libraries are bundled into packages and copied next to macOS binaries
  (oak_copy_otio_runtime)
- fix ProjectViewModel drag&drop mime read/write size mismatch (segfault)
- unify color label naming (k_olive -> "Oak") in the app-side mirror
- docs: OTIO required, FFmpeg minimum corrected to 6.0 (en/zh)
- gtest suite: 1925 passed, 0 failed

app/panel/curve/curve.cpp

@@ -49,9 +49,15 @@ void CurvePanel::deselect_all()
 	static_cast<CurveWidget *>(get_time_based_widget())->deselect_all();
 }
 
-void CurvePanel::set_nodes(const QVector<Node *> &nodes)
+void CurvePanel::set_nodes(const QVector<OakEngineNode *> &nodes)
 {
-	static_cast<CurveWidget *>(get_time_based_widget())->set_nodes(nodes);
+	// Convert to oak::Node for the curve widget (C ABI wrapper layer)
+	QVector<oak::Node> oak_nodes;
+	oak_nodes.reserve(nodes.size());
+	foreach (OakEngineNode *n, nodes) {
+		oak_nodes.append(oak::Node(n));
+	}
+	static_cast<CurveWidget *>(get_time_based_widget())->set_nodes(oak_nodes);
 }
 
 void CurvePanel::increase_track_height()

app/panel/curve/curve.h

@@ -43,20 +43,17 @@ public slots:
 	void set_node(OakEngineNode *node)
 	{
 		// Convert single pointer to either an empty vector or a vector of one
-		QVector<Node *> nodes;
+		QVector<OakEngineNode *> nodes;
 
 		if (node) {
-			nodes.append(reinterpret_cast<Node *>(node));
+			nodes.append(node);
 		}
 
 		set_nodes(nodes);
 	}
 
 public:
-	// Not a slot: signature uses the engine C++ type Node*, which must not be
-	// exposed to MOC (it would pull Node::staticMetaObject across the ABI
-	// boundary). All connections use new-style member-function syntax.
-	void set_nodes(const QVector<Node *> &nodes);
+	void set_nodes(const QVector<OakEngineNode *> &nodes);
 
 public slots:
 	virtual void increase_track_height() override;

app/panel/node/node.h

@@ -43,7 +43,7 @@ public:
 		return node_widget_;
 	}
 
-	const QVector<Node *> &get_contexts() const
+	const QVector<oak::Node> &get_contexts() const
 	{
 		return node_widget_->view()->get_contexts();
 	}
@@ -53,12 +53,12 @@ public:
 		return node_widget_->view()->is_group_overlay();
 	}
 
-	void set_contexts(const QVector<Node *> &nodes)
+	void set_contexts(const QVector<oak::Node> &nodes)
 	{
 		node_widget_->set_contexts(nodes);
 	}
 
-	void close_contexts_belonging_to_project(Project *project)
+	void close_contexts_belonging_to_project(oak::Project project)
 	{
 		node_widget_->view()->close_contexts_belonging_to_project(project);
 	}

app/panel/param/param.cpp

@@ -57,7 +57,7 @@ void ParamPanel::deselect_all()
 	static_cast<NodeParamView *>(get_time_based_widget())->deselect_all();
 }
 
-void ParamPanel::set_contexts(const QVector<Node *> &contexts)
+void ParamPanel::set_contexts(const QVector<oak::Node> &contexts)
 {
 	static_cast<NodeParamView *>(get_time_based_widget())->set_contexts(contexts);
 }

app/panel/param/param.h

@@ -39,12 +39,12 @@ public:
 		return static_cast<NodeParamView *>(get_time_based_widget());
 	}
 
-	const QVector<Node *> &get_contexts() const
+	const QVector<oak::Node> &get_contexts() const
 	{
 		return get_param_view()->get_contexts();
 	}
 
-	void close_contexts_belonging_to_project(Project *p)
+	void close_contexts_belonging_to_project(oak::Project p)
 	{
 		get_param_view()->close_contexts_belonging_to_project(p);
 	}
@@ -63,10 +63,9 @@ public slots:
 	virtual void deselect_all() override;
 
 public:
-	// Not a slot: signature uses the engine C++ type Node*, which must not be
-	// exposed to MOC (it would pull Node::staticMetaObject across the ABI
-	// boundary). All connections use new-style member-function syntax.
-	void set_contexts(const QVector<Node *> &contexts);
+	// Not a slot: mirrors NodePanel::set_contexts(), which is also a plain
+	// member function. All connections use new-style member-function syntax.
+	void set_contexts(const QVector<oak::Node> &contexts);
 
 signals:
 	void focused_node_changed(OakEngineNode *n);

app/panel/project/footagemanagementpanel.h

@@ -24,8 +24,6 @@
 
 #include <QList>
 
-#include "node/project/footage/footage.h"
-
 struct OakEngineNode;
 
 namespace olive

app/panel/project/project.cpp

@@ -27,7 +27,6 @@
 #include "core.h"
 #include "oakengine/events.h"
 #include "oakengine/project.h"
-#include "node/project/sequence/sequence.h"
 #include "panel/footageviewer/footageviewer.h"
 #include "panel/timeline/timeline.h"
 #include "panel/panelmanager.h"
@@ -89,12 +88,12 @@ ProjectPanel::ProjectPanel(const QString &unique_name)
 	retranslate();
 }
 
-Project *ProjectPanel::project() const
+oak::Project ProjectPanel::project() const
 {
 	return explorer_->project();
 }
 
-void ProjectPanel::set_project(Project *p)
+void ProjectPanel::set_project(oak::Project p)
 {
 	if (project()) {
 		if (project_name_sub_ > 0) {
@@ -106,9 +105,8 @@ void ProjectPanel::set_project(Project *p)
 	explorer_->set_project(p);
 
 	if (project()) {
-		auto *ph = reinterpret_cast<OakEngineProject *>(project());
 		project_name_sub_ = oakengine_event_subscribe(
-			ph, OAKENGINE_EVENT_PROJECT_NAME_CHANGED,
+			project().handle(), OAKENGINE_EVENT_PROJECT_NAME_CHANGED,
 			[](const oakengine_event *, void *userdata) {
 				auto *s = static_cast<ProjectPanel *>(userdata);
 				s->update_subtitle();
@@ -122,24 +120,24 @@ void ProjectPanel::set_project(Project *p)
 	emit project_name_changed();
 }
 
-Folder *ProjectPanel::get_root() const
+oak::Node ProjectPanel::get_root() const
 {
 	return explorer_->get_root();
 }
 
-void ProjectPanel::set_root(Folder *item)
+void ProjectPanel::set_root(oak::Node item)
 {
 	explorer_->set_root(item);
 
 	retranslate();
 }
 
-QVector<Node *> ProjectPanel::selected_items() const
+QVector<oak::Node> ProjectPanel::selected_items() const
 {
 	return explorer_->selected_items();
 }
 
-Folder *ProjectPanel::get_selected_folder() const
+oak::Node ProjectPanel::get_selected_folder() const
 {
 	return explorer_->get_selected_folder();
 }
@@ -176,7 +174,7 @@ void ProjectPanel::edit(OakEngineNode *item)
 
 void ProjectPanel::retranslate()
 {
-	if (project() && explorer_->get_root() != project()->root()) {
+	if (project() && explorer_->get_root() != project().root()) {
 		set_title(tr("Folder"));
 	} else {
 		set_title(tr("Project"));
@@ -187,21 +185,20 @@ void ProjectPanel::retranslate()
 
 void ProjectPanel::item_double_click_slot(OakEngineNode *item_handle)
 {
-	Node *item = reinterpret_cast<Node *>(item_handle);
+	oak::Node item(item_handle);
 	if (item == nullptr) {
 		// If the user double clicks on empty space, show the import dialog
 		Core::instance()->dialog_import_show();
-	} else if (dynamic_cast<Footage *>(item)) {
+	} else if (item.is_footage()) {
 		// Open this footage in a FootageViewer
 		auto panel =
 			PanelManager::instance()->most_recently_focused<FootageViewerPanel>();
-		panel->connect_viewer_node(static_cast<Footage *>(item));
+		panel->connect_viewer_node(item.handle());
 		panel->raise();
 		panel->setFocus(Qt::FocusReason::MouseFocusReason);
-	} else if (dynamic_cast<Sequence *>(item)) {
+	} else if (item.is_sequence()) {
 		// Open this sequence in the Timeline
-		Core::instance()->main_window()->open_sequence(
-			static_cast<Sequence *>(item));
+		Core::instance()->main_window()->open_sequence(item.handle());
 	}
 }
 
@@ -217,23 +214,19 @@ void ProjectPanel::show_new_menu()
 void ProjectPanel::update_subtitle()
 {
 	if (project()) {
-		char name_buf[256];
-		oakengine_project_name(
-			reinterpret_cast<OakEngineProject *>(project()),
-			name_buf, sizeof(name_buf));
-		QString project_title = QString::fromUtf8(name_buf);
+		QString project_title = project().name();
 
-		if (explorer_->get_root() != project()->root()) {
+		if (explorer_->get_root() != project().root()) {
 			QString folder_path;
 
-			Folder *item = explorer_->get_root();
+			oak::Node item = explorer_->get_root();
 
 			do {
 				folder_path.prepend(
-					QStringLiteral("/%1").arg(item->get_label()));
+					QStringLiteral("/%1").arg(item.get_label()));
 
-				item = item->folder();
-			} while (item != project()->root());
+				item = item.folder();
+			} while (item != project().root());
 
 			project_title.append(folder_path);
 		}
@@ -251,12 +244,12 @@ void ProjectPanel::save_connected_project()
 
 QVector<OakEngineNode *> ProjectPanel::get_selected_footage() const
 {
-	QVector<Node *> items = selected_items();
+	QVector<oak::Node> items = selected_items();
 	QVector<OakEngineNode *> footage;
 
-	foreach (Node *i, items) {
-		if (dynamic_cast<ViewerOutput *>(i)) {
-			footage.append(reinterpret_cast<OakEngineNode *>(i));
+	foreach (const oak::Node &i, items) {
+		if (i.is_viewer_output()) {
+			footage.append(i.handle());
 		}
 	}
 

app/panel/project/project.h

@@ -23,7 +23,6 @@
 #define OAK_PROJECT_PANEL_H
 
 #include "footagemanagementpanel.h"
-#include "node/project.h"
 #include "panel/panel.h"
 #include "widget/projectexplorer/projectexplorer.h"
 
@@ -41,22 +40,22 @@ public:
 	ProjectPanel(const QString &unique_name);
 	~ProjectPanel() override;
 
-	Project *project() const;
-	void set_project(Project *p);
+	oak::Project project() const;
+	void set_project(oak::Project p);
 
-	Folder *get_root() const;
+	oak::Node get_root() const;
 
-	void set_root(Folder *item);
+	void set_root(oak::Node item);
 
-	QVector<Node *> selected_items() const;
+	QVector<oak::Node> selected_items() const;
 
-	Folder *get_selected_folder() const;
+	oak::Node get_selected_folder() const;
 
 	virtual QVector<OakEngineNode *> get_selected_footage() const override;
 
 	ProjectViewModel *model() const;
 
-	bool select_item(Node *n, bool deselect_all_first = true)
+	bool select_item(oak::Node n, bool deselect_all_first = true)
 	{
 		return explorer_->select_item(n, deselect_all_first);
 	}

app/panel/sequenceviewer/sequenceviewer.cpp

@@ -33,7 +33,7 @@ SequenceViewerPanel::SequenceViewerPanel()
 }
 
 void SequenceViewerPanel::start_capture(const TimeRange &time,
-									   const Track::Reference &track)
+										const TrackReference &track)
 {
 	TimelinePanel *tp = static_cast<TimelinePanel *>(sender());
 	static_cast<ViewerWidget *>(get_time_based_widget())

app/panel/sequenceviewer/sequenceviewer.h

@@ -22,6 +22,7 @@
 #ifndef OAK_SEQUENCEVIEWERPANEL_H
 #define OAK_SEQUENCEVIEWERPANEL_H
 
+#include "common/trackreferencehandle.h"
 #include "panel/viewer/viewer.h"
 
 namespace olive
@@ -33,7 +34,7 @@ public:
 	SequenceViewerPanel();
 
 public slots:
-	void start_capture(const TimeRange &time, const Track::Reference &track);
+	void start_capture(const TimeRange &time, const TrackReference &track);
 
 protected:
 	virtual void retranslate() override;

app/panel/table/table.h

@@ -34,15 +34,12 @@ public:
 	NodeTablePanel();
 
 public:
-	// Not slots: signatures use the engine C++ type Node*, which must not be
-	// exposed to MOC (it would pull Node::staticMetaObject across the ABI
-	// boundary). All connections use new-style member-function syntax.
-	void select_nodes(const QVector<Node *> &nodes)
+	void select_nodes(const QVector<OakEngineNode *> &nodes)
 	{
 		static_cast<NodeTableWidget *>(get_time_based_widget())->select_nodes(nodes);
 	}
 
-	void deselect_nodes(const QVector<Node *> &nodes)
+	void deselect_nodes(const QVector<OakEngineNode *> &nodes)
 	{
 		static_cast<NodeTableWidget *>(get_time_based_widget())
 			->deselect_nodes(nodes);

app/panel/timebased/timebased.cpp

@@ -21,6 +21,8 @@
 
 #include "timebased.h"
 
+#include "oakutil/oaknode.h"
+
 namespace olive
 {
 
@@ -116,7 +118,7 @@ void TimeBasedPanel::shuttle_right()
 	emit shuttle_right_requested();
 }
 
-void TimeBasedPanel::connect_viewer_node(ViewerOutput *node)
+void TimeBasedPanel::connect_viewer_node(OakEngineNode *node)
 {
 	widget_->connect_viewer_node(node);
 }
@@ -140,8 +142,8 @@ void TimeBasedPanel::set_time_based_widget(TimeBasedWidget *widget)
 
 void TimeBasedPanel::retranslate()
 {
-	if (get_time_based_widget()->get_connected_node()) {
-		set_subtitle(get_time_based_widget()->get_connected_node()->get_label());
+	if (get_connected_viewer()) {
+		set_subtitle(oak::Node(get_connected_viewer()).get_label());
 	} else {
 		set_subtitle(tr("(none)"));
 	}

app/panel/timebased/timebased.h

@@ -36,7 +36,7 @@ public:
 
 	virtual ~TimeBasedPanel() override;
 
-	void connect_viewer_node(ViewerOutput *node);
+	void connect_viewer_node(OakEngineNode *node);
 
 	void disconnect_viewer_node()
 	{
@@ -46,7 +46,7 @@ public:
 	// Get the timebase of this panels widget
 	const Rational &timebase();
 
-	ViewerOutput *get_connected_viewer() const
+	OakEngineNode *get_connected_viewer() const
 	{
 		return widget_->get_connected_node();
 	}

app/panel/timeline/timeline.h

@@ -22,6 +22,7 @@
 #ifndef OAK_TIMELINE_PANEL_H
 #define OAK_TIMELINE_PANEL_H
 
+#include "common/trackreferencehandle.h"
 #include "panel/timebased/timebased.h"
 #include "widget/timelinewidget/timelinewidget.h"
 
@@ -107,14 +108,29 @@ public:
 
 	void overwrite_footage_at_playhead(const QVector<OakEngineNode *> &footage);
 
-	const QVector<Block *> &get_selected_blocks() const
+	QVector<OakEngineBlock *> get_selected_blocks() const
 	{
-		return timeline_widget()->get_selected_blocks();
+		// TimelineWidget still exposes engine Block* (its own wave converts
+		// it); re-wrap into the handle family here so callers never see the
+		// engine type.
+		const auto &selected = timeline_widget()->get_selected_blocks();
+		QVector<OakEngineBlock *> handles;
+		handles.reserve(selected.size());
+		for (auto *b : selected) {
+			handles.append(reinterpret_cast<OakEngineBlock *>(b));
+		}
+		return handles;
 	}
 
-	Sequence *get_sequence() const
+	OakEngineSequence *get_sequence() const
 	{
-		return dynamic_cast<Sequence *>(get_connected_viewer());
+		// R8: type check via the C ABI facade predicate (replaces
+		// dynamic_cast<Sequence*>, which needed the complete engine type);
+		// the handle is shared, so the cast is a reinterpret.
+		OakEngineNode *connected = get_connected_viewer();
+		return (connected && oakengine_node_is_sequence(connected))
+				   ? reinterpret_cast<OakEngineSequence *>(connected)
+				   : nullptr;
 	}
 
 protected:
@@ -124,7 +140,7 @@ signals:
 	void block_selection_changed(const QVector<OakEngineBlock *> &selected_blocks);
 
 	void request_capture_start(const TimeRange &time,
-							 const Track::Reference &track);
+							 const TrackReference &track);
 
 	void reveal_viewer_in_project(OakEngineNode *r);
 	void reveal_viewer_in_footage_viewer(OakEngineNode *r, const TimeRange &range);

app/panel/viewer/viewerbase.cpp

@@ -95,7 +95,7 @@ void ViewerPanelBase::set_full_screen(QScreen *screen)
 
 void ViewerPanelBase::set_gizmos(OakEngineNode *node)
 {
-	get_viewer_widget()->set_gizmos(reinterpret_cast<Node *>(node));
+	get_viewer_widget()->set_gizmos(node);
 }
 
 void ViewerPanelBase::cache_entire_sequence()

app/panel/viewer/viewerbase.h

@@ -76,7 +76,7 @@ public:
 		get_viewer_widget()->add_playback_device(vw);
 	}
 
-	void set_timeline_selected_blocks(const QVector<Block *> &b)
+	void set_timeline_selected_blocks(const QVector<OakEngineBlock *> &b)
 	{
 		get_viewer_widget()->set_timeline_selected_blocks(b);
 	}