WiiRoot: Fix empty files being created when source is missing

CopyNandFile must not create empty files on the destination filesystem
if the source file doesn't exist.

Otherwise, this can lead to an empty Mii database being created in the
session Wii root if there's no database in the configured Wii root and
netplay or Movie is used -- that database would then be copied back to
the configured root, which causes games like MKW to complain about
corrupted Mii data even when the player has stopped using netplay.

This commit also simplifies CreateFullPath usage.
There's no need to manually extract the directory from the path,
FS::CreateFullPath does it automatically just like File::CreateFullPath

1 files changed, 9 insertions, 9 deletions

diff --git a/Source/Core/Core/WiiRoot.cpp b/Source/Core/Core/WiiRoot.cpp
index 4096504867..aba484c0de 100644
--- a/Source/Core/Core/WiiRoot.cpp
+++ b/Source/Core/Core/WiiRoot.cpp
@@ -80,21 +80,21 @@ static void CopySave(FS::FileSystem* source, FS::FileSystem* dest, const u64 tit
 static bool CopyNandFile(FS::FileSystem* source_fs, const std::string& source_file,
                          FS::FileSystem* dest_fs, const std::string& dest_file)
 {
-  const auto last_slash = dest_file.find_last_of('/');
-  if (last_slash != std::string::npos && last_slash > 0)
-  {
-    const std::string dir = dest_file.substr(0, last_slash);
-    dest_fs->CreateFullPath(IOS::PID_KERNEL, IOS::PID_KERNEL, dir + '/', 0,
-                            {FS::Mode::ReadWrite, FS::Mode::ReadWrite, FS::Mode::ReadWrite});
-  }
-
   auto source_handle =
       source_fs->OpenFile(IOS::PID_KERNEL, IOS::PID_KERNEL, source_file, IOS::HLE::FS::Mode::Read);
+  // If the source file doesn't exist, there is nothing more to do.
+  // This function must not create an empty file on the destination filesystem.
+  if (!source_handle)
+    return true;
+
+  dest_fs->CreateFullPath(IOS::PID_KERNEL, IOS::PID_KERNEL, dest_file, 0,
+                          {FS::Mode::ReadWrite, FS::Mode::ReadWrite, FS::Mode::ReadWrite});
+
   auto dest_handle =
       dest_fs->CreateAndOpenFile(IOS::PID_KERNEL, IOS::PID_KERNEL, source_file,
                                  {IOS::HLE::FS::Mode::ReadWrite, IOS::HLE::FS::Mode::ReadWrite,
                                   IOS::HLE::FS::Mode::ReadWrite});
-  if (!source_handle || !dest_handle)
+  if (!dest_handle)
     return false;
 
   std::vector<u8> buffer(source_handle->GetStatus()->size);