MemoryCard: When converting a file to a folder, simulate the conversion process once before writing the data. This prevents half-converted/corrupted cards by ensuring we crash before any actual writes occur.

pcsx2/gui/Dialogs/ConvertMemoryCardDialog.cpp

@@ -201,9 +201,17 @@ bool Dialogs::ConvertMemoryCardDialog::ConvertToFolder( const wxFileName& source
 	AppConfig::McdOptions config;
 	config.Enabled = true;
 	config.Type = MemoryCardType::MemoryCard_Folder;
-	targetFolderMemoryCard.Open( targetPath.GetFullPath(), config, 0, false, L"" );
-
 	u32 adr = 0;
+
+	for ( int i = 0; i < 2; ++i ) {
+		// Before writing the data, we first simulate the entire process without actual writes to the file system.
+		// This ensures that if we crash/fail due to a corrupted memory card file system or similar, we do so during
+		// the simulation run, and don't actually write out any partial data to the host file system.
+		bool simulateWrites = i == 0;
+		targetFolderMemoryCard.Open( targetPath.GetFullPath(), config, 0, false, L"", simulateWrites );
+
+		adr = 0;
+		sourceFile.Seek( 0 );
 		while ( !sourceFile.Eof() ) {
 			int size = sourceFile.Read( buffer, FolderMemoryCard::PageSizeRaw );
 			if ( size > 0 ) {
@@ -212,8 +220,10 @@ bool Dialogs::ConvertMemoryCardDialog::ConvertToFolder( const wxFileName& source
 			}
 		}
 
-	sourceFile.Close();
 		targetFolderMemoryCard.Close();
+	}
+
+	sourceFile.Close();
 
 	if ( adr != FolderMemoryCard::TotalSizeRaw ) {
 		// reset memory card metrics in superblock to the default 8MB, since the converted card was different

pcsx2/gui/MemoryCardFolder.cpp

@@ -44,6 +44,7 @@ void FolderMemoryCard::InitializeInternalData() {
 	m_isEnabled = false;
 	m_framesUntilFlush = 0;
 	m_lastAccessedFile.Close();
+	m_performFileWrites = true;
 }
 
 bool FolderMemoryCard::IsFormatted() const {
@@ -52,11 +53,12 @@ bool FolderMemoryCard::IsFormatted() const {
 }
 
 void FolderMemoryCard::Open( const bool enableFiltering, const wxString& filter ) {
-	Open( g_Conf->FullpathToMcd( m_slot ), g_Conf->Mcd[m_slot], 0, enableFiltering, filter );
+	Open( g_Conf->FullpathToMcd( m_slot ), g_Conf->Mcd[m_slot], 0, enableFiltering, filter, false );
 }
 
-void FolderMemoryCard::Open( const wxString& fullPath, const AppConfig::McdOptions& mcdOptions, const u32 sizeInClusters, const bool enableFiltering, const wxString& filter ) {
+void FolderMemoryCard::Open( const wxString& fullPath, const AppConfig::McdOptions& mcdOptions, const u32 sizeInClusters, const bool enableFiltering, const wxString& filter, bool simulateFileWrites ) {
 	InitializeInternalData();
+	m_performFileWrites = !simulateFileWrites;
 
 	wxFileName configuredFileName( fullPath );
 	m_folderName = wxFileName( configuredFileName.GetFullPath() + L"/" );
@@ -74,7 +76,7 @@ void FolderMemoryCard::Open( const wxString& fullPath, const AppConfig::McdOptio
 		}
 
 		// if nothing exists at a valid location, create a directory for the memory card
-		if ( !disabled && !m_folderName.DirExists() ) {
+		if ( !disabled && m_performFileWrites && !m_folderName.DirExists() ) {
 			if ( !m_folderName.Mkdir() ) {
 				str = L"[couldn't create folder]";
 				disabled = true;
@@ -910,7 +912,7 @@ bool FolderMemoryCard::FlushBlock( const u32 block ) {
 }
 
 void FolderMemoryCard::FlushSuperBlock() {
-	if ( FlushBlock( 0 ) ) {
+	if ( FlushBlock( 0 ) && m_performFileWrites ) {
 		wxFileName superBlockFileName( m_folderName.GetPath(), L"_pcsx2_superblock" );
 		wxFFile superBlockFile( superBlockFileName.GetFullPath().c_str(), L"wb" );
 		if ( superBlockFile.IsOpened() ) {
@@ -946,6 +948,7 @@ void FolderMemoryCard::FlushFileEntries( const u32 dirCluster, const u32 remaini
 				const wxString subDirName = wxString::FromAscii( (const char*)cleanName );
 				const wxString subDirPath = dirPath + L"/" + subDirName;
 
+				if ( m_performFileWrites ) {
 					// if this directory has nonstandard metadata, write that to the file system
 					wxFileName metaFileName( m_folderName.GetFullPath() + subDirPath + L"/_pcsx2_meta_directory" );
 					if ( filenameCleaned || entry->entry.data.mode != MemoryCardFileEntry::DefaultDirMode || entry->entry.data.attr != 0 ) {
@@ -963,6 +966,7 @@ void FolderMemoryCard::FlushFileEntries( const u32 dirCluster, const u32 remaini
 							wxRemoveFile( metaFileName.GetFullPath() );
 						}
 					}
+				}
 
 				MemoryCardFileMetadataReference* dirRef = AddDirEntryToMetadataQuickAccess( entry, parent );
 
@@ -1105,6 +1109,8 @@ bool FolderMemoryCard::WriteToFile( const u8* src, u32 adr, u32 dataLength ) {
 	if ( it != m_fileMetadataQuickAccess.end() ) {
 		const MemoryCardFileEntry* const entry = it->second.entry;
 		const u32 clusterNumber = it->second.consecutiveCluster;
+		
+		if ( m_performFileWrites ) {
 			wxFFile* file = m_lastAccessedFile.ReOpen( m_folderName, &it->second, L"r+b", true );
 			if ( file->IsOpened() ) {
 				const u32 clusterOffset = ( page % 2 ) * PageSize + offset;
@@ -1133,6 +1139,7 @@ bool FolderMemoryCard::WriteToFile( const u8* src, u32 adr, u32 dataLength ) {
 			} else {
 				return false;
 			}
+		}
 
 		return true;
 	}

pcsx2/gui/MemoryCardFolder.h

@@ -283,6 +283,9 @@ protected:
 
 	bool m_isEnabled;
 
+	// if set to false, nothing is actually written to the file system while flushing, and data is discarded instead
+	bool m_performFileWrites;
+
 public:
 	FolderMemoryCard();
 	virtual ~FolderMemoryCard() throw() {}
@@ -293,7 +296,7 @@ public:
 	// Initialize & Load Memory Card with values configured in the Memory Card Manager
 	void Open( const bool enableFiltering, const wxString& filter );
 	// Initialize & Load Memory Card with provided custom values
-	void Open( const wxString& fullPath, const AppConfig::McdOptions& mcdOptions, const u32 sizeInClusters, const bool enableFiltering, const wxString& filter );
+	void Open( const wxString& fullPath, const AppConfig::McdOptions& mcdOptions, const u32 sizeInClusters, const bool enableFiltering, const wxString& filter, bool simulateFileWrites = false );
 	// Close the memory card and flush changes to the file system. Set flush to false to not store changes.
 	void Close( bool flush = true );