file_sys/registered_cache: Use unique_ptr and regular pointers instead of shared_ptrs where applicable

The data retrieved in these cases are ultimately chiefly owned by either
the RegisteredCache instance itself, or the filesystem factories. Both
these should live throughout the use of their contained data. If they
don't, it should be considered an interface/design issue, and using
shared_ptr instances here would mask that, as the data would always be
prolonged after the main owner's lifetime ended.

This makes the lifetime of the data explicit and makes it harder to
accidentally create cyclic references. It also makes the interface
slightly more flexible than the previous API, as a shared_ptr can be
created from a unique_ptr, but not the other way around, so this allows
for that use-case if it ever becomes necessary in some form.

3 files changed, 11 insertions, 12 deletions

diff --git a/src/core/hle/service/filesystem/filesystem.cpp b/src/core/hle/service/filesystem/filesystem.cpp
index e06712603..e32a7c48e 100644
--- a/src/core/hle/service/filesystem/filesystem.cpp
+++ b/src/core/hle/service/filesystem/filesystem.cpp
@@ -319,13 +319,12 @@ ResultVal<FileSys::VirtualDir> OpenSDMC() {
     return sdmc_factory->Open();
 }
 
-std::shared_ptr<FileSys::RegisteredCacheUnion> GetUnionContents() {
-    return std::make_shared<FileSys::RegisteredCacheUnion>(
-        std::vector<std::shared_ptr<FileSys::RegisteredCache>>{
-            GetSystemNANDContents(), GetUserNANDContents(), GetSDMCContents()});
+std::unique_ptr<FileSys::RegisteredCacheUnion> GetUnionContents() {
+    return std::make_unique<FileSys::RegisteredCacheUnion>(std::vector<FileSys::RegisteredCache*>{
+        GetSystemNANDContents(), GetUserNANDContents(), GetSDMCContents()});
 }
 
-std::shared_ptr<FileSys::RegisteredCache> GetSystemNANDContents() {
+FileSys::RegisteredCache* GetSystemNANDContents() {
     LOG_TRACE(Service_FS, "Opening System NAND Contents");
 
     if (bis_factory == nullptr)
@@ -334,7 +333,7 @@ std::shared_ptr<FileSys::RegisteredCache> GetSystemNANDContents() {
     return bis_factory->GetSystemNANDContents();
 }
 
-std::shared_ptr<FileSys::RegisteredCache> GetUserNANDContents() {
+FileSys::RegisteredCache* GetUserNANDContents() {
     LOG_TRACE(Service_FS, "Opening User NAND Contents");
 
     if (bis_factory == nullptr)
@@ -343,7 +342,7 @@ std::shared_ptr<FileSys::RegisteredCache> GetUserNANDContents() {
     return bis_factory->GetUserNANDContents();
 }
 
-std::shared_ptr<FileSys::RegisteredCache> GetSDMCContents() {
+FileSys::RegisteredCache* GetSDMCContents() {
     LOG_TRACE(Service_FS, "Opening SDMC Contents");
 
     if (sdmc_factory == nullptr)
diff --git a/src/core/hle/service/filesystem/filesystem.h b/src/core/hle/service/filesystem/filesystem.h
index 2df1faeb0..6ca5c5636 100644
--- a/src/core/hle/service/filesystem/filesystem.h
+++ b/src/core/hle/service/filesystem/filesystem.h
@@ -47,11 +47,11 @@ ResultVal<FileSys::VirtualDir> OpenSaveData(FileSys::SaveDataSpaceId space,
                                             FileSys::SaveDataDescriptor save_struct);
 ResultVal<FileSys::VirtualDir> OpenSDMC();
 
-std::shared_ptr<FileSys::RegisteredCacheUnion> GetUnionContents();
+std::unique_ptr<FileSys::RegisteredCacheUnion> GetUnionContents();
 
-std::shared_ptr<FileSys::RegisteredCache> GetSystemNANDContents();
-std::shared_ptr<FileSys::RegisteredCache> GetUserNANDContents();
-std::shared_ptr<FileSys::RegisteredCache> GetSDMCContents();
+FileSys::RegisteredCache* GetSystemNANDContents();
+FileSys::RegisteredCache* GetUserNANDContents();
+FileSys::RegisteredCache* GetSDMCContents();
 
 FileSys::VirtualDir GetModificationLoadRoot(u64 title_id);
 
diff --git a/src/core/hle/service/ns/pl_u.cpp b/src/core/hle/service/ns/pl_u.cpp
index 4b2f758a8..44accecb7 100644
--- a/src/core/hle/service/ns/pl_u.cpp
+++ b/src/core/hle/service/ns/pl_u.cpp
@@ -161,7 +161,7 @@ PL_U::PL_U() : ServiceFramework("pl:u"), impl{std::make_unique<Impl>()} {
     };
     RegisterHandlers(functions);
     // Attempt to load shared font data from disk
-    const auto nand = FileSystem::GetSystemNANDContents();
+    const auto* nand = FileSystem::GetSystemNANDContents();
     std::size_t offset = 0;
     // Rebuild shared fonts from data ncas
     if (nand->HasEntry(static_cast<u64>(FontArchives::Standard),