RMG: add minidump handler in main.cpp

Source/RMG/main.cpp

@@ -17,7 +17,10 @@
 #include <iostream>
 #include <cstdlib>
 
-#ifndef _WIN32
+#ifdef _WIN32
+#include <Windows.h>
+#include <wchar.h>
+#else
 #include <signal.h>
 #endif
 
@@ -42,10 +45,79 @@ static void message_handler(QtMsgType type, const QMessageLogContext &context, c
     std::cerr << msg.toStdString() << std::endl;
 }
 
+#ifdef _WIN32
+typedef BOOL (WINAPI* ptr_MiniDumpWriteDump)(HANDLE, DWORD, HANDLE, MINIDUMP_TYPE,
+                                             PMINIDUMP_EXCEPTION_INFORMATION,
+                                             PMINIDUMP_USER_STREAM_INFORMATION,
+                                             PMINIDUMP_CALLBACK_INFORMATION);
+static void show_error(const char* error)
+{
+    MessageBoxA(nullptr, error, "RMG Crash Handler", MB_OK | MB_ICONERROR);
+}
+
+static LONG WINAPI exception_handler(_EXCEPTION_POINTERS* ExceptionInfo)
+{
+    HMODULE dbgHelpModule = LoadLibraryA("Dbghelp.dll");
+    if (dbgHelpModule == nullptr)
+    {
+        show_error("Failed to find Dbghelp.dll!");
+        return EXCEPTION_CONTINUE_SEARCH;
+    }
+
+    ptr_MiniDumpWriteDump miniDumpWriteDump = 
+        (ptr_MiniDumpWriteDump)GetProcAddress(dbgHelpModule, "MiniDumpWriteDump");
+    if (miniDumpWriteDump == nullptr)
+    {
+        show_error("Failed to retrieve MiniDumpWriteDump from Dbghelp.dll!");
+        return EXCEPTION_CONTINUE_SEARCH;
+    }
+
+    wchar_t dump_filename[MAX_PATH+1] = {0};
+    DWORD filename_len = GetModuleFileNameW(nullptr, dump_filename, MAX_PATH);
+    if (filename_len <= 0)
+    {
+        show_error("Failed to retrieve path of current process!");
+        return EXCEPTION_CONTINUE_SEARCH;
+    }
+
+    if (filename_len >= MAX_PATH)
+    { // replace .exe with .dmp
+        wcscpy((dump_filename + (filename_len - 4)), ".dmp");
+    }
+    else
+    { // append .dmp to .exe
+        wcscpy((dump_filename + filename_len), ".dmp");
+    }
+
+    HANDLE hDumpFile = CreateFileW(dump_filename, GENERIC_WRITE, FILE_SHARE_WRITE, 
+                                   nullptr, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, nullptr);
+
+    if (hDumpFile != INVALID_HANDLE_VALUE)
+    {
+        _MINIDUMP_EXCEPTION_INFORMATION exceptionInfo;
+        exceptionInfo.ThreadId = GetCurrentThreadId();
+        exceptionInfo.ExceptionPointers = pExceptionInfo;
+        exceptionInfo.ClientPointers = nullptr;
+
+        BOOL ret = miniDumpWriteDump(GetCurrentProcess(), GetCurrentProcessId(), 
+                                     hDumpFile, MiniDumpNormal, &exceptionInfo, 
+                                     nullptr, nullptr);
+        if (!ret)
+        {
+            show_error("Crash detected, failed to save minidump file!");
+        }
+    }
+
+    // we've saved the minidump,
+    // now we can crash safely
+    return EXCEPTION_CONTINUE_SEARCH;
+}
+#else
 static void signal_handler(int sig)
 {
     QGuiApplication::quit();
 }
+#endif // _WIN32
 
 //
 // Exported Functions
@@ -56,7 +128,12 @@ int main(int argc, char **argv)
     // install message handler
     qInstallMessageHandler(message_handler);
 
-#ifndef _WIN32
+#ifdef _WIN32
+    // on Windows, to aid with crash debugging
+    // we'll install a crash handler and
+    // write out a minidump there
+    SetUnhandledExceptionFilter(exception_handler);
+#else
     // on Linux we need to install signal handlers,
     // so we can exit cleanly when the user presses
     // i.e control+c