From 6ae7e24675cff4ff6b808c3024f45083f35ced97 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20Ankarstr=C3=B6m?= <john@ankarstrom.se>
Date: Sat, 3 Sep 2022 15:28:56 +0200
Subject: Improve error handling.

---
 c/err.cpp | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 c/err.cpp

(limited to 'c/err.cpp')

diff --git a/c/err.cpp b/c/err.cpp
new file mode 100644
index 0000000..fd35ddd
--- /dev/null
+++ b/c/err.cpp
@@ -0,0 +1,87 @@
+#include <exception>
+#include <windows.h>
+#include <wininet.h>
+#include <libxml/xmlerror.h>
+
+#include "err.h"
+#include "util.h"
+#include "win32.h"
+
+Err::Err(ErrType t, const wchar_t* fmt)
+{
+	switch (t) {
+	case GENERIC:
+		what = fmt;
+		break;
+	case WINDOWS:
+	    {
+		wchar_t* msg;
+		DWORD lenMsg = FormatMessageW(
+		    FORMAT_MESSAGE_ALLOCATE_BUFFER
+		    |FORMAT_MESSAGE_FROM_SYSTEM
+		    |FORMAT_MESSAGE_IGNORE_INSERTS,
+		    nullptr,
+		    GetLastError(),
+		    MAKELANGID(LANG_ENGLISH, SUBLANG_ENGLISH_US),
+		    (wchar_t*)&msg,
+		    0, nullptr);
+		what = std::wstring(lenMsg+wcslen(fmt), 0);
+		Swprintf(what, fmt, msg);
+		HeapFree(GetProcessHeap(), 0, msg);
+		break;
+	    }
+	case WININET:
+	    {
+		DWORD code = GetLastError();
+		if (code == ERROR_INTERNET_EXTENDED_ERROR) {
+			DWORD lenMsg;
+			InternetGetLastResponseInfo(&code, nullptr, &lenMsg);
+			std::wstring msg(lenMsg, 0);
+			if (InternetGetLastResponseInfoW(&code, msg.data(), &lenMsg)) {
+				what = std::wstring(lenMsg+wcslen(fmt), 0);
+				Swprintf(what, fmt, msg.c_str());
+				EBMessageBox(msg, L"Test");
+			} else
+				what = Err(WINDOWS, fmt).what;
+		} else {
+			wchar_t* wszMsg;
+			DWORD lenMsg = FormatMessageW(
+			    FORMAT_MESSAGE_ALLOCATE_BUFFER
+			    |FORMAT_MESSAGE_FROM_SYSTEM
+			    |FORMAT_MESSAGE_FROM_HMODULE
+			    |FORMAT_MESSAGE_IGNORE_INSERTS,
+			    GetModuleHandle(L"wininet.dll"),
+			    code,
+			    MAKELANGID(LANG_ENGLISH, SUBLANG_ENGLISH_US),
+			    (wchar_t*)&wszMsg,
+			    0, nullptr);
+			what = std::wstring(lenMsg+wcslen(fmt), 0);
+			Swprintf(what, fmt, wszMsg);
+			HeapFree(GetProcessHeap(), 0, wszMsg);
+		}
+		break;
+	    }
+	case LIBXML2:
+	    {
+		std::wstring msg = WideFromNarrow(xmlGetLastError()->message);
+		what = std::wstring(msg.size()+wcslen(fmt), 0);
+		Swprintf(what, fmt, msg.c_str());
+		break;
+	    }
+	}
+}
+
+std::wstring What(std::exception_ptr ex)
+{
+	try {
+		std::rethrow_exception(ex);
+	} catch (const Err& e) {
+		return e.what;
+	} catch (const WideException& e) {
+		return e.What();
+	} catch (const std::exception& e) {
+		return WideFromNarrow(e.what());
+	} catch (...) {
+		return L"Unknown exception";
+	}
+}
-- 
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