IOS/FS: Make the NAND root path a parameter

Cleaner than having the backend figure out which NAND root to use.

Source/Core/Core/IOS/FS/FileSystem.cpp

@@ -5,13 +5,16 @@
 #include "Core/IOS/FS/FileSystem.h"
 
 #include "Common/Assert.h"
+#include "Common/FileUtil.h"
 #include "Core/IOS/FS/HostBackend/FS.h"
 
 namespace IOS::HLE::FS
 {
-std::unique_ptr<FileSystem> MakeFileSystem()
+std::unique_ptr<FileSystem> MakeFileSystem(Location location)
 {
-  return std::make_unique<HostFileSystem>();
+  const std::string nand_root =
+      File::GetUserPath(location == Location::Session ? D_SESSION_WIIROOT_IDX : D_WIIROOT_IDX);
+  return std::make_unique<HostFileSystem>(nand_root);
 }
 
 FileHandle::FileHandle(FileSystem* fs, Fd fd) : m_fs{fs}, m_fd{fd}

Source/Core/Core/IOS/FS/FileSystem.h

@@ -195,6 +195,12 @@ protected:
   void Init();
 };
 
-std::unique_ptr<FileSystem> MakeFileSystem();
+enum class Location
+{
+  Configured,
+  Session,
+};
+
+std::unique_ptr<FileSystem> MakeFileSystem(Location location = Location::Session);
 
 }  // namespace IOS::HLE::FS

Source/Core/Core/IOS/FS/HostBackend/FS.cpp

@@ -20,14 +20,13 @@ static bool IsValidWiiPath(const std::string& path)
   return path.compare(0, 1, "/") == 0;
 }
 
-std::string HostFileSystem::BuildFilename(const std::string& wii_path)
+std::string HostFileSystem::BuildFilename(const std::string& wii_path) const
 {
-  std::string nand_path = File::GetUserPath(D_SESSION_WIIROOT_IDX);
   if (wii_path.compare(0, 1, "/") == 0)
-    return nand_path + Common::EscapePath(wii_path);
+    return m_root_path + Common::EscapePath(wii_path);
 
   ASSERT(false);
-  return nand_path;
+  return m_root_path;
 }
 
 // Get total filesize of contents of a directory (recursive)
@@ -45,7 +44,7 @@ static u64 ComputeTotalFileSize(const File::FSTEntry& parent_entry)
   return sizeOfFiles;
 }
 
-HostFileSystem::HostFileSystem()
+HostFileSystem::HostFileSystem(const std::string& root_path) : m_root_path{root_path}
 {
   Init();
 }
@@ -54,6 +53,8 @@ HostFileSystem::~HostFileSystem() = default;
 
 void HostFileSystem::DoState(PointerWrap& p)
 {
+  p.Do(m_root_path);
+
   // Temporarily close the file, to prevent any issues with the savestating of /tmp
   for (Handle& handle : m_handles)
     handle.host_file.reset();

Source/Core/Core/IOS/FS/HostBackend/FS.h

@@ -23,7 +23,7 @@ namespace IOS::HLE::FS
 class HostFileSystem final : public FileSystem
 {
 public:
-  HostFileSystem();
+  HostFileSystem(const std::string& root_path);
   ~HostFileSystem();
 
   void DoState(PointerWrap& p) override;
@@ -73,9 +73,10 @@ private:
   Handle* GetHandleFromFd(Fd fd);
   Fd ConvertHandleToFd(const Handle* handle) const;
 
-  std::string BuildFilename(const std::string& wii_path);
+  std::string BuildFilename(const std::string& wii_path) const;
   std::shared_ptr<File::IOFile> OpenHostFile(const std::string& host_path);
 
+  std::string m_root_path;
   std::array<Handle, 16> m_handles{};
   std::map<std::string, std::weak_ptr<File::IOFile>> m_open_files;
 };