#5907: EntityClass::getVisibility() returns value from spawnargs

Instead of a constant value, getVisibility() now returns the correct
value based on the presence of an "editor_visibility" spawnarg. The
value is initialised lazily by way of a new Lazy class template which
provides a generic means of lazily initialising a value using a callback
function.

libs/generic/Lazy.h

@@ -0,0 +1,30 @@
+#pragma once
+
+#include <optional>
+#include <functional>
+
+/// Wrapper for an arbitrary object which is initialised lazily via a functor
+template<typename T> class Lazy
+{
+    // Contained value (may or may not be initialised)
+    mutable std::optional<T> _value;
+
+    // Functor to initialise _value when required
+    using InitialiseFunc = std::function<T()>;
+    InitialiseFunc _initFunc;
+
+public:
+
+    /// Construct the Lazy wrapper with a functor to be called when initialisation is required
+    Lazy(InitialiseFunc func): _initFunc(func)
+    {}
+
+    /// Return the contained value, initialising via the functor if necessary
+    T get() const
+    {
+        if (!_value)
+            _value = _initFunc();
+
+        return *_value;
+    }
+};

radiantcore/eclass/EClassManager.cpp

@@ -129,18 +129,15 @@ void EClassManager::resolveModelInheritance(const std::string& name, const Doom3
 
 void EClassManager::parseDefFiles()
 {
-	rMessage() << "searching vfs directory 'def' for *.def\n";
+    // Increase the parse stamp for this run
+    _curParseStamp++;
 
-	// Increase the parse stamp for this run
-	_curParseStamp++;
-
-	{
-		ScopedDebugTimer timer("EntityDefs parsed: ");
+    {
+        ScopedDebugTimer timer("EntityDefs parsed: ");
         GlobalFileSystem().forEachFile(
-            "def/", "def",
-            [&](const vfs::FileInfo& fileInfo) { parseFile(fileInfo); }
+            "def/", "def", [&](const vfs::FileInfo& fileInfo) { parseFile(fileInfo); }
         );
-	}
+    }
 }
 
 void EClassManager::resolveInheritance()

radiantcore/eclass/EntityClass.cpp

@@ -19,6 +19,10 @@ namespace
 
 EntityClass::EntityClass(const std::string& name, bool fixedSize)
 : _name(name),
+  _visibility([this]() {
+      return (getAttributeValue("editor_visibility") == "hidden" ? vfs::Visibility::HIDDEN
+                                                                 : vfs::Visibility::NORMAL);
+  }),
   _colour(UndefinedColour),
   _fixedSize(fixedSize)
 {}
@@ -41,7 +45,7 @@ const IEntityClass* EntityClass::getParent() const
 
 vfs::Visibility EntityClass::getVisibility() const
 {
-    return _visibility;
+    return _visibility.get();
 }
 
 sigc::signal<void>& EntityClass::changedSignal()

radiantcore/eclass/EntityClass.h

@@ -7,6 +7,7 @@
 #include "math/Vector3.h"
 #include "math/AABB.h"
 #include "string/string.h"
+#include "generic/Lazy.h"
 
 #include "parser/DefTokeniser.h"
 
@@ -43,7 +44,7 @@ class EntityClass
     EntityClass* _parent = nullptr;
 
     // UI visibility of this entity class
-    vfs::Visibility _visibility = vfs::Visibility::NORMAL;
+    Lazy<vfs::Visibility> _visibility;
 
     // Should this entity type be treated as a light?
     bool _isLight = false;

test/Entity.cpp

@@ -1999,6 +1999,7 @@ TEST_F(EntityTest, GetEClassVisibility)
     // Hidden entity
     auto entityBase = GlobalEntityClassManager().findClass("atdm:entity_base");
     ASSERT_TRUE(entityBase);
+    EXPECT_EQ(entityBase->getAttributeValue("editor_visibility"), "hidden");
     EXPECT_EQ(entityBase->getVisibility(), vfs::Visibility::HIDDEN);
 }