timeline: auto-unlink blocks when they're deleted

app/widget/timelinewidget/timelinewidget.cpp

@@ -380,6 +380,8 @@ void TimelineWidget::DeleteSelectedInternal(const QList<Block *> &blocks,
     }
 
     if (remove_from_graph) {
+      new BlockUnlinkAllCommand(b, command);
+
       new NodeRemoveWithExclusiveDeps(static_cast<NodeGraph*>(b->parent()), b, command);
     }
   }

app/widget/timelinewidget/undo/undo.cpp

@@ -715,3 +715,52 @@ void WorkareaSetRangeCommand::undo_internal()
 {
   points_->workarea()->set_range(old_range_);
 }
+
+BlockLinkCommand::BlockLinkCommand(const QList<Block *> &blocks, bool link, QUndoCommand *parent) :
+  UndoCommand(parent),
+  blocks_(blocks),
+  link_(link)
+{
+}
+
+void BlockLinkCommand::redo_internal()
+{
+  if (link_) {
+    Block::Link(blocks_);
+  } else {
+    Block::Unlink(blocks_);
+  }
+}
+
+void BlockLinkCommand::undo_internal()
+{
+  if (link_) {
+    Block::Unlink(blocks_);
+  } else {
+    Block::Link(blocks_);
+  }
+}
+
+BlockUnlinkAllCommand::BlockUnlinkAllCommand(Block *block, QUndoCommand *parent) :
+  UndoCommand(parent),
+  block_(block)
+{
+}
+
+void BlockUnlinkAllCommand::redo_internal()
+{
+  unlinked_ = block_->linked_clips();
+
+  foreach (Block* link, unlinked_) {
+    Block::Unlink(block_, link);
+  }
+}
+
+void BlockUnlinkAllCommand::undo_internal()
+{
+  foreach (Block* link, unlinked_) {
+    Block::Link(block_, link);
+  }
+
+  unlinked_.clear();
+}

app/widget/timelinewidget/undo/undo.h

@@ -331,4 +331,34 @@ private:
 
 };
 
+class BlockLinkCommand : public UndoCommand {
+public:
+  BlockLinkCommand(const QList<Block*>& blocks, bool link, QUndoCommand* parent = nullptr);
+
+protected:
+  virtual void redo_internal() override;
+  virtual void undo_internal() override;
+
+private:
+  QList<Block*> blocks_;
+
+  bool link_;
+
+};
+
+class BlockUnlinkAllCommand : public UndoCommand {
+public:
+  BlockUnlinkAllCommand(Block* block, QUndoCommand* parent = nullptr);
+
+protected:
+  virtual void redo_internal() override;
+  virtual void undo_internal() override;
+
+private:
+  Block* block_;
+
+  QVector<Block*> unlinked_;
+
+};
+
 #endif // TIMELINEUNDOABLE_H