Cascading remove test

Bigfoot/Sources/Engine/Asset/AssetLibrary.cpp

@@ -69,9 +69,9 @@ bool AssetLibrary::IsLoaded(const UUID& p_uuid) const
 
 /****************************************************************************************/
 
-void AssetLibrary::ProcessPendingRemovals() { 
-
-    for (const auto [typeId, container] : m_assetContainers)
+void AssetLibrary::ProcessPendingRemovals()
+{
+    for (const auto [typeId, container]: m_assetContainers)
     {
         container->ProcessPendingRemovals();
     }

Bigfoot/Sources/Engine/Include/Engine/Asset/AssetContainer.hpp

@@ -27,11 +27,11 @@ class ContainerHandle
 {
   public:
     /**
-    * Constructor
-    * 
-    * \param p_assetContainer The originating assetcontainer
-    * \param p_uuid The UUID of tha asset
-    */
+     * Constructor
+     *
+     * \param p_assetContainer The originating assetcontainer
+     * \param p_uuid The UUID of tha asset
+     */
     ContainerHandle(AssetContainerBase* p_assetContainer, const UUID p_uuid);
 
     /*

Bigfoot/Sources/Engine/Include/Engine/Asset/AssetLibrary.hpp

@@ -91,9 +91,9 @@ class AssetLibrary
     bool IsLoaded(const UUID& p_uuid) const;
 
     /**
-    * Loop through the AssetContainers to remove the pending assets marked for removal
-    * 
-    */
+     * Loop through the AssetContainers to remove the pending assets marked for removal
+     *
+     */
     void ProcessPendingRemovals();
 
     AssetLibrary& operator=(const AssetLibrary& p_library) = default;

Bigfoot/Tests/Engine/Asset/AssetLibrary.cpp

@@ -170,6 +170,70 @@ TEST_F(AssetLibraryFixture, ProcessPendingRemovals_ShouldNotRemoveAssetsThatAreN
 
 /****************************************************************************************/
 
+TEST_F(AssetLibraryFixture, ProcessPendingRemovals_ShouldCascadeThroughHardReferencedAssetsOneLevelPerCall)
+{
+    UUID leafUUID;
+    UUID middleUUID;
+    UUID rootUUID;
+
+    {
+        // leaf
+        AssetA* leaf = static_cast<AssetA*>(m_containerA.Insert()->GetAsset());
+        leafUUID = leaf->GetHeader().uuid;
+
+        // middle --> leaf
+        AssetB* middle = static_cast<AssetB*>(m_containerB.Insert()->GetAsset());
+        middle->GetAsset().ref_a = HardReference<AssetA> {leafUUID};
+        middleUUID = middle->GetHeader().uuid;
+
+        //   root
+        //   /  \
+        //  v    v
+        // middle --> leaf
+        AssetC* root = static_cast<AssetC*>(m_containerC.Insert()->GetAsset());
+        root->GetAsset().asset_b_ref = HardReference<AssetB> {middleUUID};
+        root->GetAsset().inner_table->asset_a_ref = HardReference<AssetA> {leafUUID};
+        rootUUID = root->GetHeader().uuid;
+
+        const HardReference<AssetC> rootRef {rootUUID};
+        const HardReference<AssetB> middleRef {middleUUID};
+        const HardReference<AssetA> leafRef {leafUUID};
+
+        ASSERT_NE(rootRef.Get(), nullptr);
+        ASSERT_NE(middleRef.Get(), nullptr);
+        ASSERT_NE(leafRef.Get(), nullptr);
+    }
+
+    // Releasing the outer HardReferences only drops root's count to zero: middle and leaf are
+    // still kept alive by root's own internal HardReferences to them.
+    EXPECT_TRUE(m_containerC.IsMarkedForRemove(rootUUID));
+    EXPECT_FALSE(m_containerB.IsMarkedForRemove(middleUUID));
+    EXPECT_FALSE(m_containerA.IsMarkedForRemove(leafUUID));
+    EXPECT_TRUE(m_library.IsLoaded(rootUUID));
+    EXPECT_TRUE(m_library.IsLoaded(middleUUID));
+    EXPECT_TRUE(m_library.IsLoaded(leafUUID));
+
+    // 1st pass: removing root destroys its HardReference to middle, dropping middle's count to
+    // zero; leaf is still held alive by middle's own HardReference to it.
+    m_library.ProcessPendingRemovals();
+    EXPECT_FALSE(m_library.IsLoaded(rootUUID));
+    EXPECT_TRUE(m_containerB.IsMarkedForRemove(middleUUID));
+    EXPECT_TRUE(m_library.IsLoaded(middleUUID));
+    EXPECT_TRUE(m_library.IsLoaded(leafUUID));
+
+    // 2nd pass: removing middle destroys its HardReference to leaf, dropping leaf's count to zero.
+    m_library.ProcessPendingRemovals();
+    EXPECT_FALSE(m_library.IsLoaded(middleUUID));
+    EXPECT_TRUE(m_containerA.IsMarkedForRemove(leafUUID));
+    EXPECT_TRUE(m_library.IsLoaded(leafUUID));
+
+    // 3rd pass: nothing references leaf anymore, it finally gets removed.
+    m_library.ProcessPendingRemovals();
+    EXPECT_FALSE(m_library.IsLoaded(leafUUID));
+}
+
+/****************************************************************************************/
+
 TEST_F(AssetLibraryFixture, SetActiveAssetLibrary_ShouldSetTheActiveAssetLibraryToTheGivenLibrary)
 {
     SetActiveAssetLibrary(&m_library);