1 files changed, 163 insertions, 0 deletions
diff --git a/source/core/slang-lazy-castable-list.cpp b/source/core/slang-lazy-castable-list.cpp
new file mode 100644
index 000000000..d9f0090d5
--- /dev/null
+++ b/source/core/slang-lazy-castable-list.cpp
@@ -0,0 +1,163 @@
+// slang-lazy-castable-list.cpp
+#include "slang-lazy-castable-list.h"
+
+#include "slang-castable-list-impl.h"
+
+namespace Slang {
+
+void LazyCastableList::removeAt(Index index)
+{
+    SLANG_ASSERT(index >= 0 && index < getCount());
+
+    switch (m_state)
+    {
+        case State::None:   break;
+        case State::One:    
+        {
+            m_state = State::None;
+            m_castable.setNull();
+            break;
+        }
+        case State::List:   
+        {
+            static_cast<ICastableList*>(m_castable.get())->removeAt(index);
+            break;
+        }
+    }
+}
+
+void LazyCastableList::clear()
+{
+    if (m_state == State::List)
+    {
+        auto list = static_cast<ICastableList*>(m_castable.get());
+        list->clear();
+    }
+    else
+    {
+        m_state = State::None;
+        m_castable.setNull();
+    }
+}
+
+void LazyCastableList::clearAndDeallocate()
+{
+    m_state = State::None;
+    m_castable.setNull();
+}
+
+Count LazyCastableList::getCount() const
+{
+    switch (m_state)
+    {
+        case State::None:   return 0;
+        case State::One:    return 1;
+        default:
+        case State::List:   return static_cast<ICastableList*>(m_castable.get())->getCount();
+    }
+}
+
+void LazyCastableList::add(ICastable* castable)
+{
+    SLANG_ASSERT(castable);
+    if (m_state == State::None)
+    {
+        m_castable = castable;
+        m_state = State::One;
+    }
+    else
+    {
+        requireList()->add(castable);
+    }
+}
+
+ICastableList* LazyCastableList::requireList()
+{
+    switch (m_state)
+    {
+        case State::None:
+        {
+            m_castable = new CastableList;
+            m_state = State::List;
+            break;
+        }
+        case State::One:
+        {
+            // Turn into a list
+            auto list = new CastableList;
+            list->add(m_castable);
+            m_castable = list;
+            m_state = State::List;
+            break;
+        }
+        default: break;
+    }
+    SLANG_ASSERT(m_state == State::List);
+    return static_cast<ICastableList*>(m_castable.get());
+}
+
+ICastableList* LazyCastableList::getList()
+{
+    return (m_state == State::None) ? nullptr : requireList();
+}
+
+void* LazyCastableList::find(const Guid& guid)
+{
+    for (auto castable : getView())
+    {
+        if (auto ptr = castable->castAs(guid))
+        {
+            return ptr;
+        }
+    }
+    return nullptr;
+}
+ 
+ConstArrayView<ICastable*> LazyCastableList::getView() const
+{
+    switch (m_state)
+    {
+        case State::None: return ConstArrayView<ICastable*>();
+        case State::One:  return ConstArrayView<ICastable*>((ICastable*const*)&m_castable, 1);
+        default:
+        case State::List:
+        {
+            auto list = static_cast<ICastableList*>(m_castable.get());
+            return ConstArrayView<ICastable*>(list->getBuffer(), list->getCount());
+        }
+    }
+}
+
+Index LazyCastableList::indexOf(ICastable* castable) const
+{
+    return getView().indexOf(castable);
+}
+
+Index LazyCastableList::indexOfUnknown(ISlangUnknown* unk) const
+{
+    // Try as a ICastable first
+    {
+        ComPtr<ICastable> castable;
+        if (SLANG_SUCCEEDED(unk->queryInterface(ICastable::getTypeGuid(), (void**)castable.writeRef())) && castable)
+        {
+            return indexOf(castable);
+        }
+    }
+
+    // It's not derived from ICastable, so can only be in list via an adapter
+    const auto view = getView();
+
+    const Count count = view.getCount();
+    for (Index i = 0; i < count; ++i)
+    {
+        auto adapter = as<IUnknownCastableAdapter>(view[i]);
+        if (adapter && adapter->getContained() == unk)
+        {
+            return i;
+        }
+    }
+
+    return -1;
+}
+
+} // namespace Slang