1 files changed, 26 insertions, 27 deletions

diff --git a/src/core/loader/deconstructed_rom_directory.cpp b/src/core/loader/deconstructed_rom_directory.cpp
index 94dd3395ba..463a8c8930 100644
--- a/src/core/loader/deconstructed_rom_directory.cpp
+++ b/src/core/loader/deconstructed_rom_directory.cpp
@@ -8,6 +8,8 @@
 #include <cctype>
 #include <chrono>
 #include <cstring>
+#include <map>
+#include <memory>
 #include <mutex>
 #include <string_view>
 #include "common/logging.h"
@@ -92,31 +94,24 @@ FileSys::VirtualFile FindLooseRomFS(const FileSys::VirtualDir& exefs_dir) {
     }
     if (const auto parent = exefs_dir->GetParentDirectory()) {
         if (const auto romfs_dir = parent->GetSubdirectory("romfs")) {
-            // Keep no ownership here: launch preparation hands its image to the real loader.
+            // Building it walks every file and keeps an object for each (title 1: 206k files, ~150
+            // MiB), so loaders of the same directory share one build while any of them holds it.
             static std::mutex cache_mutex;
-            static std::string cached_path;
-            static std::weak_ptr<FileSys::VfsFile> cached_romfs;
-            const auto path = romfs_dir->GetFullPath();
-            {
-                std::scoped_lock lock{cache_mutex};
-                if (cached_path == path) {
-                    if (auto cached = cached_romfs.lock()) {
-                        return cached;
-                    }
-                }
+            static std::map<std::string, std::weak_ptr<FileSys::VfsFile>> cache;
+            std::scoped_lock lk{cache_mutex};
+            auto& cached = cache[romfs_dir->GetFullPath()];
+            if (auto built = cached.lock()) {
+                return built;
             }
+            LOG_INFO(Loader, "Using RomFS directory next to the ExeFS");
             const auto started = std::chrono::steady_clock::now();
-            LOG_INFO(Loader, "Building loose RomFS directory image");
-            auto image = FileSys::CreateRomFS(romfs_dir);
+            auto built = FileSys::CreateRomFS(romfs_dir);
             LOG_INFO(Loader, "Loose RomFS image ready: elapsed_ms={}",
                      std::chrono::duration_cast<std::chrono::milliseconds>(
-                         std::chrono::steady_clock::now() - started).count());
-            {
-                std::scoped_lock lock{cache_mutex};
-                cached_path = path;
-                cached_romfs = image;
-            }
-            return image;
+                         std::chrono::steady_clock::now() - started)
+                         .count());
+            cached = built;
+            return built;
         }
     }
     return nullptr;
@@ -258,6 +253,7 @@ AppLoader_DeconstructedRomDirectory::AppLoader_DeconstructedRomDirectory(FileSys
         name = control->GetApplicationName();
     }
 
+    romfs_exefs_dir = file_dir;
     if (const auto title_dir = file_dir->GetParentDirectory()) {
         romfs_version = RomFSProductVersion(title_dir->GetSubdirectory("romfs"));
     }
@@ -269,13 +265,17 @@ AppLoader_DeconstructedRomDirectory::AppLoader_DeconstructedRomDirectory(
     , dir(std::move(directory))
     , override_update(override_update_)
 {
+    romfs_exefs_dir = dir;
 }
 
-void AppLoader_DeconstructedRomDirectory::EnsureRomFS() {
-    if (!romfs_initialized) {
-        romfs = FindLooseRomFS(dir ? dir : file->GetContainingDirectory());
-        romfs_initialized = true;
+// Loaders made only for metadata (the game list, title lookups) never need the RomFS, and several
+// of them were alive with a whole copy each.
+const FileSys::VirtualFile& AppLoader_DeconstructedRomDirectory::LooseRomFS() {
+    if (!romfs_resolved) {
+        romfs_resolved = true;
+        romfs = FindLooseRomFS(romfs_exefs_dir);
     }
+    return romfs;
 }
 
 FileType AppLoader_DeconstructedRomDirectory::IdentifyType(const FileSys::VirtualFile& dir_file) {
@@ -336,7 +336,7 @@ AppLoader_DeconstructedRomDirectory::LoadResult AppLoader_DeconstructedRomDirect
 
     // Loose-ExeFS loads bypass the NCA/NSP loaders, which are the ones that normally apply
     // LayeredFS to the RomFS; apply it here so mods in user/load/<titleid>/ work too.
-    if (romfs != nullptr) {
+    if (LooseRomFS() != nullptr) {
         const FileSys::PatchManager patch_manager(metadata.GetTitleID(),
                                                   system.GetFileSystemController(),
                                                   system.GetContentProvider());
@@ -446,8 +446,7 @@ AppLoader_DeconstructedRomDirectory::LoadResult AppLoader_DeconstructedRomDirect
 }
 
 ResultStatus AppLoader_DeconstructedRomDirectory::ReadRomFS(FileSys::VirtualFile& out_dir) {
-    EnsureRomFS();
-    if (romfs == nullptr) {
+    if (LooseRomFS() == nullptr) {
         return ResultStatus::ErrorNoRomFS;
     }