timeline: reimplemented linking/unlinking functionality

app/widget/menu/menushared.cpp

@@ -52,7 +52,7 @@ MenuShared::MenuShared()
 
   // "Clip Edit" menu shared items
   clip_add_default_transition_item_ = Menu::CreateItem(this, "deftransition", nullptr, nullptr, "Ctrl+Shift+D");
-  clip_link_unlink_item_ = Menu::CreateItem(this, "linkunlink", nullptr, nullptr, "Ctrl+L");
+  clip_link_unlink_item_ = Menu::CreateItem(this, "linkunlink", this, SLOT(ToggleLinksTriggered()), "Ctrl+L");
   clip_enable_disable_item_ = Menu::CreateItem(this, "enabledisable", nullptr, nullptr, "Shift+E");
   clip_nest_item_ = Menu::CreateItem(this, "nest", nullptr, nullptr);
 
@@ -156,6 +156,11 @@ void MenuShared::ClearInOutTriggered()
   PanelManager::instance()->CurrentlyFocused()->ClearInOut();
 }
 
+void MenuShared::ToggleLinksTriggered()
+{
+  PanelManager::instance()->CurrentlyFocused()->ToggleLinks();
+}
+
 void MenuShared::Retranslate()
 {
   // "New" menu shared items

app/widget/menu/menushared.h

@@ -91,6 +91,8 @@ private slots:
 
   void ClearInOutTriggered();
 
+  void ToggleLinksTriggered();
+
 };
 
 #endif // MENUSHARED_H

app/widget/panel/panel.h

@@ -130,6 +130,8 @@ public:
 
   virtual void SetMarker(){}
 
+  virtual void ToggleLinks(){}
+
 protected:
   /**
    * @brief paintEvent

app/widget/timelinewidget/timelinewidget.cpp

@@ -472,6 +472,30 @@ void TimelineWidget::OverwriteFootageAtPlayhead(const QList<Footage *> &footage)
   import_tool_->PlaceAt(footage, GetTime(), false);
 }
 
+void TimelineWidget::ToggleLinksOnSelected()
+{
+  QList<TimelineViewBlockItem*> sel = GetSelectedBlocks();
+
+  // Prioritize unlinking
+
+  QList<Block*> blocks;
+  bool link = true;
+
+  foreach (TimelineViewBlockItem* item, sel) {
+    if (link && item->block()->HasLinks()) {
+      link = false;
+    }
+
+    blocks.append(item->block());
+  }
+
+  if (link) {
+    Core::instance()->undo_stack()->push(new BlockLinkManyCommand(blocks, true));
+  } else {
+    Core::instance()->undo_stack()->push(new BlockLinkManyCommand(blocks, false));
+  }
+}
+
 QList<TimelineViewBlockItem *> TimelineWidget::GetSelectedBlocks()
 {
   QList<TimelineViewBlockItem *> list;
@@ -687,6 +711,7 @@ void TimelineWidget::AddBlock(Block *block, TrackReference track)
     views_.at(track.type())->view()->scene()->addItem(item);
 
     connect(block, &Block::Refreshed, this, &TimelineWidget::BlockChanged);
+    connect(block, &Block::LinksChanged, this, &TimelineWidget::PreviewUpdated);
 
     if (block->type() == Block::kClip) {
       connect(static_cast<ClipBlock*>(block), &ClipBlock::PreviewUpdated, this, &TimelineWidget::PreviewUpdated);

app/widget/timelinewidget/timelinewidget.h

@@ -57,6 +57,8 @@ public:
 
   void OverwriteFootageAtPlayhead(const QList<Footage *> &footage);
 
+  void ToggleLinksOnSelected();
+
   QList<TimelineViewBlockItem*> GetSelectedBlocks();
 
 signals:

app/widget/timelinewidget/undo/undo.cpp

@@ -716,9 +716,10 @@ void WorkareaSetRangeCommand::undo_internal()
   points_->workarea()->set_range(old_range_);
 }
 
-BlockLinkCommand::BlockLinkCommand(const QList<Block *> &blocks, bool link, QUndoCommand *parent) :
+BlockLinkCommand::BlockLinkCommand(Block *a, Block *b, bool link, QUndoCommand *parent) :
   UndoCommand(parent),
-  blocks_(blocks),
+  a_(a),
+  b_(b),
   link_(link)
 {
 }
@@ -726,18 +727,20 @@ BlockLinkCommand::BlockLinkCommand(const QList<Block *> &blocks, bool link, QUnd
 void BlockLinkCommand::redo_internal()
 {
   if (link_) {
-    Block::Link(blocks_);
+    done_ = Block::Link(a_, b_);
   } else {
-    Block::Unlink(blocks_);
+    done_ = Block::Unlink(a_, b_);
   }
 }
 
 void BlockLinkCommand::undo_internal()
 {
-  if (link_) {
-    Block::Unlink(blocks_);
-  } else {
-    Block::Link(blocks_);
+  if (done_) {
+    if (link_) {
+      Block::Unlink(a_, b_);
+    } else {
+      Block::Link(a_, b_);
+    }
   }
 }
 
@@ -764,3 +767,15 @@ void BlockUnlinkAllCommand::undo_internal()
 
   unlinked_.clear();
 }
+
+BlockLinkManyCommand::BlockLinkManyCommand(const QList<Block *> blocks, bool link, QUndoCommand *parent) :
+  UndoCommand(parent)
+{
+  foreach (Block* a, blocks) {
+    foreach (Block* b, blocks) {
+      if (a != b) {
+        new BlockLinkCommand(a, b, link, this);
+      }
+    }
+  }
+}

app/widget/timelinewidget/undo/undo.h

@@ -331,19 +331,28 @@ private:
 
 };
 
+class BlockLinkManyCommand : public UndoCommand {
+public:
+  BlockLinkManyCommand(const QList<Block*> blocks, bool link, QUndoCommand* parent = nullptr);
+};
+
 class BlockLinkCommand : public UndoCommand {
 public:
-  BlockLinkCommand(const QList<Block*>& blocks, bool link, QUndoCommand* parent = nullptr);
+  BlockLinkCommand(Block* a, Block* b, bool link, QUndoCommand* parent = nullptr);
 
 protected:
   virtual void redo_internal() override;
   virtual void undo_internal() override;
 
 private:
-  QList<Block*> blocks_;
+  Block* a_;
+
+  Block* b_;
 
   bool link_;
 
+  bool done_;
+
 };
 
 class BlockUnlinkAllCommand : public UndoCommand {