From 0a6e088ebe874cd6ee5e926f482f3717a93b42fe Mon Sep 17 00:00:00 2001
From: Ricardo Antunes <me@riscadoa.com>
Date: Fri, 27 Sep 2024 13:03:16 +0200
Subject: [PATCH] feat(assets): allow unloading a metadata directory

---
 engine/include/cubos/engine/assets/assets.hpp |  8 ++++++
 engine/src/assets/assets.cpp                  | 24 +++++++++++++++++
 engine/src/assets/bridges/file.cpp            | 27 +++++++++++++------
 3 files changed, 51 insertions(+), 8 deletions(-)

diff --git a/engine/include/cubos/engine/assets/assets.hpp b/engine/include/cubos/engine/assets/assets.hpp
index 6cfcb38ef..0419572f6 100644
--- a/engine/include/cubos/engine/assets/assets.hpp
+++ b/engine/include/cubos/engine/assets/assets.hpp
@@ -87,6 +87,14 @@ namespace cubos::engine
         /// @param path Path to load metadata from.
         void loadMeta(std::string_view path);
 
+        /// @brief Unloads all asset metadata from assets within the given path.
+        ///
+        /// If an asset from the given path is currently loaded, it will not be unloaded, but it will be dissociated
+        /// from its original metadata path.
+        ///
+        /// @param path Path to unload metadata from.
+        void unloadMeta(std::string_view path);
+
         /// @brief Loads the asset with the given handle, upgrading the handle to a strong one.
         ///
         /// This method doesn't block, thus the asset may have not yet been loaded when it returns.
diff --git a/engine/src/assets/assets.cpp b/engine/src/assets/assets.cpp
index fa3412c12..511d3ce06 100644
--- a/engine/src/assets/assets.cpp
+++ b/engine/src/assets/assets.cpp
@@ -181,6 +181,30 @@ void Assets::loadMeta(std::string_view path)
     }
 }
 
+void Assets::unloadMeta(std::string_view path)
+{
+    std::unique_lock lock(mMutex);
+
+    // Search for assets that have the given path as a prefix and remove the path from their metadata.
+    std::vector<uuids::uuid> toRemove;
+    for (auto& [id, entry] : mEntries)
+    {
+        std::unique_lock lock(entry->mutex);
+
+        if (auto metaPath = entry->meta.get("path"))
+        {
+            if (metaPath->starts_with(path))
+            {
+                entry->meta.remove("path");
+                if (entry->status == Status::Unloaded || entry->status == Status::Unknown)
+                {
+                    toRemove.push_back(id);
+                }
+            }
+        }
+    }
+}
+
 AnyAsset Assets::load(AnyAsset handle) const
 {
     auto assetEntry = this->entry(handle);
diff --git a/engine/src/assets/bridges/file.cpp b/engine/src/assets/bridges/file.cpp
index d891cadfe..d2a0dd764 100644
--- a/engine/src/assets/bridges/file.cpp
+++ b/engine/src/assets/bridges/file.cpp
@@ -11,17 +11,23 @@ using namespace cubos::engine;
 
 bool FileBridge::load(Assets& assets, const AnyAsset& handle)
 {
-    auto path = assets.readMeta(handle)->get("path").value();
-    auto stream = FileSystem::open(path, File::OpenMode::Read);
+    auto path = assets.readMeta(handle)->get("path");
+    if (!path.has_value())
+    {
+        CUBOS_ERROR("Asset does not have a file path");
+        return false;
+    }
+
+    auto stream = FileSystem::open(*path, File::OpenMode::Read);
     if (stream == nullptr)
     {
-        CUBOS_ERROR("Could not open file {}", path);
+        CUBOS_ERROR("Could not open file {}", *path);
         return false;
     }
 
     if (!this->loadFromFile(assets, handle, *stream))
     {
-        CUBOS_ERROR("Could not load asset from file {}", path);
+        CUBOS_ERROR("Could not load asset from file {}", *path);
         return false;
     }
 
@@ -30,9 +36,14 @@ bool FileBridge::load(Assets& assets, const AnyAsset& handle)
 
 bool FileBridge::save(const Assets& assets, const AnyAsset& handle)
 {
-    auto path = assets.readMeta(handle)->get("path").value();
+    auto path = assets.readMeta(handle)->get("path");
+    if (!path.has_value())
+    {
+        CUBOS_ERROR("Asset does not have a file path");
+        return false;
+    }
 
-    auto swpPath = path + ".swp";
+    auto swpPath = *path + ".swp";
     auto swpFile = FileSystem::create(swpPath);
 
     if (swpFile == nullptr)
@@ -58,9 +69,9 @@ bool FileBridge::save(const Assets& assets, const AnyAsset& handle)
     stream = nullptr;
 
     /// @todo This can be done simpler with #737.
-    if (!FileSystem::copy(swpPath, path))
+    if (!FileSystem::copy(swpPath, *path))
     {
-        CUBOS_ERROR("Could not overwrite asset {} with swap file", path);
+        CUBOS_ERROR("Could not overwrite asset {} with swap file", *path);
         return false;
     }