Qt/GCMemcardManager and Qt/GameCubePane: Give detailed error messages for invalid memory cards.

Source/Core/DolphinQt/GCMemcardManager.cpp

@@ -17,6 +17,8 @@
 #include <QLineEdit>
 #include <QPixmap>
 #include <QPushButton>
+#include <QString>
+#include <QStringList>
 #include <QTableWidget>
 #include <QTimer>
 
@@ -241,14 +243,20 @@ void GCMemcardManager::UpdateActions()
 
 void GCMemcardManager::SetSlotFile(int slot, QString path)
 {
-  // TODO: Check error codes and give reasonable error messages.
   auto [error_code, memcard] = GCMemcard::Open(path.toStdString());
 
-  if (error_code.HasCriticalErrors() || !memcard || !memcard->IsValid())
-    return;
-
-  m_slot_file_edit[slot]->setText(path);
-  m_slot_memcard[slot] = std::make_unique<GCMemcard>(std::move(*memcard));
+  if (!error_code.HasCriticalErrors() && memcard && memcard->IsValid())
+  {
+    m_slot_file_edit[slot]->setText(path);
+    m_slot_memcard[slot] = std::make_unique<GCMemcard>(std::move(*memcard));
+  }
+  else
+  {
+    m_slot_memcard[slot] = nullptr;
+    ModalMessageBox::critical(
+        this, tr("Error"),
+        tr("Failed opening memory card:\n%1").arg(GetErrorMessagesForErrorCode(error_code)));
+  }
 
   UpdateSlotTable(slot);
   UpdateActions();
@@ -524,3 +532,37 @@ std::vector<QPixmap> GCMemcardManager::GetIconFromSaveFile(int file_index, int s
 
   return frame_pixmaps;
 }
+
+QString GCMemcardManager::GetErrorMessagesForErrorCode(const GCMemcardErrorCode& code)
+{
+  QStringList sl;
+
+  if (code.Test(GCMemcardValidityIssues::FAILED_TO_OPEN))
+    sl.push_back(tr("Couldn't open file."));
+
+  if (code.Test(GCMemcardValidityIssues::IO_ERROR))
+    sl.push_back(tr("Couldn't read file."));
+
+  if (code.Test(GCMemcardValidityIssues::INVALID_CARD_SIZE))
+    sl.push_back(tr("Filesize does not match any known GameCube Memory Card size."));
+
+  if (code.Test(GCMemcardValidityIssues::MISMATCHED_CARD_SIZE))
+    sl.push_back(tr("Filesize in header mismatches actual card size."));
+
+  if (code.Test(GCMemcardValidityIssues::INVALID_CHECKSUM))
+    sl.push_back(tr("Invalid checksums."));
+
+  if (code.Test(GCMemcardValidityIssues::FREE_BLOCK_MISMATCH))
+    sl.push_back(tr("Mismatch between free block count in header and actually unused blocks."));
+
+  if (code.Test(GCMemcardValidityIssues::DIR_BAT_INCONSISTENT))
+    sl.push_back(tr("Mismatch between internal data structures."));
+
+  if (code.Test(GCMemcardValidityIssues::DATA_IN_UNUSED_AREA))
+    sl.push_back(tr("Data in area of file that should be unused."));
+
+  if (sl.empty())
+    return QStringLiteral("No errors.");
+
+  return sl.join(QStringLiteral("\n"));
+}

Source/Core/DolphinQt/GCMemcardManager.h

@@ -12,6 +12,7 @@
 #include <QDialog>
 
 class GCMemcard;
+class GCMemcardErrorCode;
 
 class QDialogButtonBox;
 class QGroupBox;
@@ -19,6 +20,7 @@ class QLabel;
 class QLineEdit;
 class QPixmap;
 class QPushButton;
+class QString;
 class QTableWidget;
 class QTimer;
 
@@ -29,6 +31,8 @@ public:
   explicit GCMemcardManager(QWidget* parent = nullptr);
   ~GCMemcardManager();
 
+  static QString GetErrorMessagesForErrorCode(const GCMemcardErrorCode& code);
+
 private:
   void CreateWidgets();
   void ConnectWidgets();

Source/Core/DolphinQt/Settings/GameCubePane.cpp

@@ -28,6 +28,7 @@
 #include "Core/HW/GCMemcard/GCMemcard.h"
 
 #include "DolphinQt/Config/Mapping/MappingWindow.h"
+#include "DolphinQt/GCMemcardManager.h"
 #include "DolphinQt/QtUtils/ModalMessageBox.h"
 
 enum
@@ -212,16 +213,15 @@ void GameCubePane::OnConfigPressed(int slot)
   {
     if (File::Exists(filename.toStdString()))
     {
-      // TODO: check error codes and give reasonable error messages
       auto [error_code, mc] = GCMemcard::Open(filename.toStdString());
 
       if (error_code.HasCriticalErrors() || !mc || !mc->IsValid())
       {
-        ModalMessageBox::critical(this, tr("Error"),
-                                  tr("Cannot use that file as a memory card.\n%1\n"
-                                     "is not a valid GameCube memory card file")
-                                      .arg(filename));
-
+        ModalMessageBox::critical(
+            this, tr("Error"),
+            tr("The file\n%1\nis either corrupted or not a GameCube memory card file.\n%2")
+                .arg(filename)
+                .arg(GCMemcardManager::GetErrorMessagesForErrorCode(error_code)));
         return;
       }
     }