Experimental file renaming without closing handle.

Source/Core/Common/CMakeLists.txt

@@ -47,6 +47,8 @@ add_library(common
   Event.h
   File.cpp
   File.h
+  FileByHandle.cpp
+  FileByHandle.h
   FileSearch.cpp
   FileSearch.h
   FileUtil.cpp

Source/Core/Common/Common.vcxproj

@@ -55,6 +55,7 @@
     <ClInclude Include="ENetUtil.h" />
     <ClInclude Include="Event.h" />
     <ClInclude Include="File.h" />
+    <ClInclude Include="FileByHandle.h" />
     <ClInclude Include="FileSearch.h" />
     <ClInclude Include="FileUtil.h" />
     <ClInclude Include="FixedSizeQueue.h" />
@@ -196,6 +197,7 @@
     <ClCompile Include="DynamicLibrary.cpp" />
     <ClCompile Include="ENetUtil.cpp" />
     <ClCompile Include="File.cpp" />
+    <ClCompile Include="FileByHandle.cpp" />
     <ClCompile Include="FileSearch.cpp" />
     <ClCompile Include="FileUtil.cpp" />
     <ClCompile Include="FloatUtils.cpp" />

Source/Core/Common/Common.vcxproj.filters

@@ -261,6 +261,7 @@
       <Filter>GL\GLExtensions</Filter>
     </ClInclude>
     <ClInclude Include="File.h" />
+    <ClInclude Include="FileByHandle.h" />
     <ClInclude Include="Lazy.h" />
     <ClInclude Include="LdrWatcher.h" />
     <ClInclude Include="GL\GLExtensions\ARB_texture_compression_bptc.h">
@@ -355,6 +356,7 @@
     <ClCompile Include="Analytics.cpp" />
     <ClCompile Include="MD5.cpp" />
     <ClCompile Include="File.cpp" />
+    <ClCompile Include="FileByHandle.cpp" />
     <ClCompile Include="LdrWatcher.cpp" />
     <ClCompile Include="CompatPatches.cpp" />
     <ClCompile Include="Config\ConfigInfo.cpp" />

Source/Core/Common/FileByHandle.cpp

@@ -0,0 +1,72 @@
+// Copyright 2020 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#include "FileByHandle.h"
+
+#include <memory>
+
+#include <Windows.h>
+
+#include "StringUtil.h"
+
+namespace File
+{
+struct IOFileByHandle::Impl
+{
+  HANDLE m_handle;
+};
+
+IOFileByHandle::IOFileByHandle(const std::string& filename) : m_data(std::make_unique<Impl>())
+{
+  auto wide_filename = UTF8ToTStr(filename);
+  m_data->m_handle = CreateFile(wide_filename.c_str(), GENERIC_READ | GENERIC_WRITE | DELETE, 0,
+                                nullptr, CREATE_ALWAYS, FILE_ATTRIBUTE_ARCHIVE, nullptr);
+  if (m_data->m_handle == INVALID_HANDLE_VALUE)
+    return;
+}
+
+IOFileByHandle::~IOFileByHandle()
+{
+  if (m_data->m_handle == INVALID_HANDLE_VALUE)
+    return;
+
+  CloseHandle(m_data->m_handle);
+}
+
+bool IOFileByHandle::Write(const u8* data, size_t length)
+{
+  if (m_data->m_handle == INVALID_HANDLE_VALUE)
+    return false;
+
+  DWORD bytes_written;
+  if (WriteFile(m_data->m_handle, data, static_cast<DWORD>(length), &bytes_written, nullptr))
+    return bytes_written == length;
+
+  return false;
+}
+
+bool IOFileByHandle::Rename(const std::string& filename)
+{
+  if (m_data->m_handle == INVALID_HANDLE_VALUE)
+    return false;
+
+  auto wide_filename = UTF8ToWString(filename);
+  size_t rename_info_length = sizeof(FILE_RENAME_INFO) + wide_filename.length() * sizeof(wchar_t);
+  auto rename_info_buffer = std::make_unique<u8[]>(rename_info_length);
+
+  FILE_RENAME_INFO* rename_info = reinterpret_cast<FILE_RENAME_INFO*>(rename_info_buffer.get());
+  rename_info->ReplaceIfExists = TRUE;
+  rename_info->FileNameLength = static_cast<DWORD>(wide_filename.length());
+  std::memcpy(rename_info->FileName, wide_filename.c_str(),
+              wide_filename.length() * sizeof(wchar_t));
+
+  if (SetFileInformationByHandle(m_data->m_handle, FileRenameInfo, rename_info_buffer.get(),
+                                 static_cast<DWORD>(rename_info_length)))
+  {
+    return true;
+  }
+
+  return false;
+}
+}  // namespace File

Source/Core/Common/FileByHandle.h

@@ -0,0 +1,38 @@
+// Copyright 2020 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+#include <string>
+
+#include "Common/CommonTypes.h"
+
+namespace File
+{
+class IOFileByHandle
+{
+public:
+  IOFileByHandle(const std::string& filename);
+  ~IOFileByHandle();
+
+  IOFileByHandle(const IOFileByHandle&) = delete;
+  IOFileByHandle& operator=(const IOFileByHandle&) = delete;
+
+  bool Write(const u8* data, size_t length);
+
+  bool Rename(const std::string& filename);
+
+  template <typename T>
+  bool WriteArray(const T* elements, size_t count)
+  {
+    return Write(reinterpret_cast<const u8*>(elements), count * sizeof(T));
+  }
+
+private:
+  struct Impl;
+  std::unique_ptr<Impl> m_data;
+};
+
+}  // namespace File

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

@@ -12,6 +12,7 @@
 
 #include "Common/Assert.h"
 #include "Common/ChunkFile.h"
+#include "Common/FileByHandle.h"
 #include "Common/FileUtil.h"
 #include "Common/Logging/Log.h"
 #include "Common/NandPaths.h"
@@ -177,16 +178,15 @@ void HostFileSystem::SaveFst()
 
   const std::string dest_path = GetFstFilePath();
   const std::string temp_path = File::GetTempFilenameForAtomicWrite(dest_path);
+
+  File::IOFileByHandle file(temp_path);
+  if (!file.WriteArray(to_write.data(), to_write.size()))
   {
-    // This temporary file must be closed before it can be renamed.
-    File::IOFile file{temp_path, "wb"};
-    if (!file.WriteArray(to_write.data(), to_write.size()))
-    {
-      PanicAlert("IOS_FS: Failed to write new FST");
-      return;
-    }
+    PanicAlert("IOS_FS: Failed to write new FST");
+    return;
   }
-  if (!File::Rename(temp_path, dest_path))
+
+  if (!file.Rename(dest_path))
     PanicAlert("IOS_FS: Failed to rename temporary FST file");
 }