IOS: Change GetFS() to return a FileSystem

Now that we have a proper filesystem interface, it makes more sense
to return it instead of the emulated IOS device (which isn't
really usable for any purpose other than emulated IPC).

Source/Core/Core/CMakeLists.txt

@@ -165,6 +165,7 @@ add_library(core
   IOS/ES/TitleInformation.cpp
   IOS/ES/TitleManagement.cpp
   IOS/ES/Views.cpp
+  IOS/FS/FileSystem.cpp
   IOS/FS/HostBackend/File.cpp
   IOS/FS/HostBackend/FS.cpp
   IOS/FS/FileIO.cpp

Source/Core/Core/Core.vcxproj

@@ -197,6 +197,7 @@
     <ClCompile Include="IOS\ES\Views.cpp" />
     <ClCompile Include="IOS\FS\FileIO.cpp" />
     <ClCompile Include="IOS\FS\FS.cpp" />
+    <ClCompile Include="IOS\FS\FileSystem.cpp" />
     <ClCompile Include="IOS\FS\HostBackend\FS.cpp" />
     <ClCompile Include="IOS\FS\HostBackend\File.cpp" />
     <ClCompile Include="IOS\Network\ICMPLin.cpp" />

Source/Core/Core/Core.vcxproj.filters

@@ -735,6 +735,9 @@
     <ClCompile Include="IOS\FS\FileIO.cpp">
       <Filter>IOS\FS</Filter>
     </ClCompile>
+    <ClCompile Include="IOS\FS\FileSystem.cpp">
+      <Filter>IOS\FS</Filter>
+    </ClCompile>
     <ClCompile Include="IOS\FS\HostBackend\FS.cpp">
       <Filter>IOS\FS</Filter>
     </ClCompile>

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

@@ -0,0 +1,15 @@
+// Copyright 2018 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#include "Core/IOS/FS/FileSystem.h"
+
+#include "Core/IOS/FS/HostBackend/FS.h"
+
+namespace IOS::HLE::FS
+{
+std::unique_ptr<FileSystem> MakeFileSystem()
+{
+  return std::make_unique<HostFileSystem>();
+}
+}  // namespace IOS::HLE::FS

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

@@ -4,6 +4,7 @@
 
 #pragma once
 
+#include <memory>
 #include <string>
 #include <vector>
 
@@ -170,4 +171,6 @@ public:
   virtual Result<DirectoryStats> GetDirectoryStats(const std::string& path) = 0;
 };
 
+std::unique_ptr<FileSystem> MakeFileSystem();
+
 }  // namespace IOS::HLE::FS

Source/Core/Core/IOS/IOS.cpp

@@ -33,6 +33,7 @@
 #include "Core/IOS/ES/ES.h"
 #include "Core/IOS/FS/FS.h"
 #include "Core/IOS/FS/FileIO.h"
+#include "Core/IOS/FS/FileSystem.h"
 #include "Core/IOS/MIOS.h"
 #include "Core/IOS/Network/IP/Top.h"
 #include "Core/IOS/Network/KD/NetKDRequest.h"
@@ -242,9 +243,9 @@ u32 Kernel::GetVersion() const
   return static_cast<u32>(m_title_id);
 }
 
-std::shared_ptr<Device::FS> Kernel::GetFS()
+std::shared_ptr<FS::FileSystem> Kernel::GetFS()
 {
-  return std::static_pointer_cast<Device::FS>(m_device_map.at("/dev/fs"));
+  return m_fs;
 }
 
 std::shared_ptr<Device::ES> Kernel::GetES()
@@ -368,6 +369,9 @@ void Kernel::AddDevice(std::unique_ptr<Device::Device> device)
 
 void Kernel::AddCoreDevices()
 {
+  m_fs = FS::MakeFileSystem();
+  ASSERT(m_fs);
+
   std::lock_guard<std::mutex> lock(m_device_map_mutex);
   AddDevice(std::make_unique<Device::FS>(*this, "/dev/fs"));
   AddDevice(std::make_unique<Device::ES>(*this, "/dev/es"));
@@ -691,6 +695,7 @@ void Kernel::DoState(PointerWrap& p)
   p.Do(m_ppc_gid);
 
   m_iosc.DoState(p);
+  m_fs->DoState(p);
 
   if (m_title_id == Titles::MIOS)
     return;

Source/Core/Core/IOS/IOS.h

@@ -23,11 +23,15 @@ namespace IOS
 {
 namespace HLE
 {
+namespace FS
+{
+class FileSystem;
+}
+
 namespace Device
 {
 class Device;
 class ES;
-class FS;
 }
 
 struct Request;
@@ -94,7 +98,7 @@ public:
 
   // These are *always* part of the IOS kernel and always available.
   // They are also the only available resource managers even before loading any module.
-  std::shared_ptr<Device::FS> GetFS();
+  std::shared_ptr<FS::FileSystem> GetFS();
   std::shared_ptr<Device::ES> GetES();
 
   void SDIO_EventNotify();
@@ -146,6 +150,7 @@ protected:
   u64 m_last_reply_time = 0;
 
   IOSC m_iosc;
+  std::shared_ptr<FS::FileSystem> m_fs;
 };
 
 // HLE for an IOS tied to emulation: base kernel which may have additional modules loaded.