From d7bb04a09c7f04b0c3a8580d6a9ccd6313656fcf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20Ankarstr=C3=B6m?= <john@ankarstrom.se>
Date: Mon, 22 Aug 2022 03:17:54 +0200
Subject: Add InternetError exception.

---
 c/win.cpp | 86 +++++++++++++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 65 insertions(+), 21 deletions(-)

(limited to 'c/win.cpp')

diff --git a/c/win.cpp b/c/win.cpp
index c7ce7ec..601f82c 100644
--- a/c/win.cpp
+++ b/c/win.cpp
@@ -2,6 +2,7 @@
 #include <string>
 #include <SWI-Prolog.h>
 #include <windows.h>
+#include <wininet.h>
 
 #include "pl.h"
 #include "util.h"
@@ -84,24 +85,29 @@ int EBMessageBox(const std::wstring_view text, const std::wstring_view caption,
 
 void ShowException(const wchar_t* const fmt, const wchar_t* const title, const UINT uType) noexcept
 {
-	const wchar_t* what = L"an exception";
-	WcharPtr why;
-
 	try {
 		std::rethrow_exception(std::current_exception());
         } catch (const term_t& t) {
-		what = L"a Prolog exception";
-		try { why = PlString(t); } catch (...) {}
-	} catch (const Win32Error& e) {
-		what = L"a Windows error";
-		try { why = WcharPtr::Copy(e.What()); } catch (...) {}
+		WcharPtr what = PlString(t);
+		std::wstring msg(wcslen(fmt)+wcslen(what), 0);
+		Swprintf(msg, fmt, static_cast<wchar_t*>(what));
+		EBMessageBox(msg, title, uType);
+	} catch (const WideException& e) {
+		std::wstring msg(wcslen(fmt)+wcslen(e.What()), 0);
+		Swprintf(msg, fmt, e.What());
+		EBMessageBox(msg, title, uType);
 	} catch (const std::exception& e) {
-		try { why = WcharPtr::FromNarrow(e.what()); } catch (...) {}
-	} catch (...) {}
+		auto what = WcharPtr::FromNarrow(e.what());
+		std::wstring msg(wcslen(fmt)+wcslen(what), 0);
+		Swprintf(msg, fmt, static_cast<wchar_t*>(what));
+		EBMessageBox(msg, title, uType);
+	} catch (...) {
+		const wchar_t* what = L"an unknown error occurred";
+		std::wstring msg(wcslen(fmt)+wcslen(what), 0);
+		Swprintf(msg, fmt, what);
+		EBMessageBox(msg, title, uType);
+	}
 
-	std::wstring msg(wcslen(fmt)+wcslen(what)+wcslen(why), 0);
-	Swprintf(msg, fmt, what, static_cast<wchar_t*>(why));
-	EBMessageBox(msg, title, uType);
 }
 
 int GetRelativeCursorPos(const HWND hWnd, POINT* const pt) noexcept
@@ -118,9 +124,6 @@ int GetRelativeCursorPos(const HWND hWnd, POINT* const pt) noexcept
 	return 1;
 }
 
-Win32Error::Win32Error() noexcept
-	: code(GetLastError()) {}
-
 Win32Error::Win32Error(const DWORD code) noexcept
 	: code(code) {}
 
@@ -136,25 +139,66 @@ const char* Win32Error::what() const noexcept
 {
 	if (!m_szMsg)
 		FormatMessageA(
-		    FORMAT_MESSAGE_ALLOCATE_BUFFER|FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS,
-		    nullptr,
+		    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),
 		    (char*)&m_szMsg,
 		    0, nullptr);
-	return m_szMsg;
+	return m_szMsg? m_szMsg: "An unknown error occurred";
 }
 
 const wchar_t* Win32Error::What() const noexcept
 {
 	if (!m_wszMsg)
 		FormatMessage(
-		    FORMAT_MESSAGE_ALLOCATE_BUFFER|FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS,
-		    nullptr,
+		    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*)&m_wszMsg,
 		    0, nullptr);
+	return m_wszMsg? m_wszMsg: L"An unknown error occurred";
+}
+
+InternetError::InternetError(DWORD codeSystem)
+{
+	if (codeSystem != ERROR_INTERNET_EXTENDED_ERROR)
+		throw Win32Error{codeSystem};
+
+	DWORD len, cch;
+	InternetGetLastResponseInfo(&code, nullptr, &len);
+
+	cch = len+1;
+	m_szMsg = new char[cch];
+	if (!InternetGetLastResponseInfoA(&code, m_szMsg, &cch))
+		throw Win32Error{};
+
+	cch = len+1;
+	m_wszMsg = new wchar_t[cch];
+	if (!InternetGetLastResponseInfo(&code, m_wszMsg, &len))
+		throw Win32Error{};
+}
+
+InternetError::~InternetError()
+{
+	delete m_szMsg;
+	delete m_wszMsg;
+}
+
+const char* InternetError::what() const noexcept
+{
+	return m_szMsg;
+}
+
+const wchar_t* InternetError::What() const noexcept
+{
 	return m_wszMsg;
 }
 
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