From 2f7b69d6d4cf18ca9ca04d9a44aaa6871ce51160 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20Ankarstr=C3=B6m?= <john@ankarstrom.se>
Date: Wed, 7 Sep 2022 00:40:26 +0200
Subject: Improve error handling.

---
 c/win32.cpp | 107 ++++++++++--------------------------------------------------
 1 file changed, 18 insertions(+), 89 deletions(-)

(limited to 'c/win32.cpp')

diff --git a/c/win32.cpp b/c/win32.cpp
index fa5116d..73316e8 100644
--- a/c/win32.cpp
+++ b/c/win32.cpp
@@ -32,17 +32,21 @@ void WithNextWindow(void (*proc)(HWND))
 
 	static thread_local void (*procNext)(HWND);
 	static thread_local HHOOK hHook;
-	procNext = proc;
-	hHook = Require(SetWindowsHookExW(WH_CBT, [](const int nCode,
+	static const auto procCBT = [](const int nCode,
 	    const WPARAM wParam, const LPARAM lParam) -> LRESULT CALLBACK
 	{
 		if (nCode == HCBT_CREATEWND) {
-			Require(UnhookWindowsHookEx(hHook));
+			if (!UnhookWindowsHookEx(hHook))
+				throw Err(WINDOWS, L"Window hook could not be removed: %s");
 			procNext(reinterpret_cast<HWND>(wParam));
 			return 0;
 		} else
 			return CallNextHookEx(0, nCode, wParam, lParam);
-	}, nullptr, GetCurrentThreadId()));
+	};
+
+	procNext = proc;
+	if (!(hHook = SetWindowsHookExW(WH_CBT, procCBT, nullptr, GetCurrentThreadId())))
+		throw Err(WINDOWS, L"Window hook could not be set: %s");
 }
 
 /* Display next created window in the center of given window. */
@@ -59,18 +63,16 @@ static void CenterNextWindow(HWND hWnd)
 	static thread_local HWND hWndParent;
 	static thread_local HWND hWndNext;
 	static thread_local HHOOK hHook;
-
-	hWndParent = hWnd;
-	hWndNext = nullptr;
-	hHook = Require(SetWindowsHookExW(WH_CBT, [](const int nCode,
-	    const WPARAM wParam, const LPARAM lParam) noexcept -> LRESULT CALLBACK
+	static const auto procCBT = [](const int nCode,
+	    const WPARAM wParam, const LPARAM lParam) -> LRESULT CALLBACK
 	{
 		if (!hWndNext && nCode == HCBT_CREATEWND) {
 			hWndNext = reinterpret_cast<HWND>(wParam);
 			return 0;
 		} else if (nCode == HCBT_ACTIVATE
 		    && reinterpret_cast<HWND>(wParam) == hWndNext) {
-			Require(UnhookWindowsHookEx(hHook));
+			if (!UnhookWindowsHookEx(hHook))
+				throw Err(WINDOWS, L"Window hook could not be removed: %s");
 
 			long lStyle = GetWindowLongW(hWndNext, GWL_STYLE);
 			if (!(lStyle & WS_POPUP)) return 0;
@@ -87,7 +89,12 @@ static void CenterNextWindow(HWND hWnd)
 			return 0;
 		} else
 			return CallNextHookEx(0, nCode, wParam, lParam);
-	}, nullptr, GetCurrentThreadId()));
+	};
+
+	hWndParent = hWnd;
+	hWndNext = nullptr;
+	if (!(hHook = SetWindowsHookExW(WH_CBT, procCBT, nullptr, GetCurrentThreadId())))
+		throw Err(WINDOWS, L"Window hook could not be set: %s");
 }
 
 int EBMessageBox(const std::wstring_view text, const std::wstring_view caption, const UINT uType)
@@ -112,84 +119,6 @@ int GetRelativeCursorPos(const HWND hWnd, POINT* const pt) noexcept
 	return 1;
 }
 
-Win32Error::Win32Error(const DWORD code, const HMODULE hModule) noexcept
-	: code(code), hModule(hModule) {}
-
-Win32Error::~Win32Error()
-{
-	if (m_szMsg)
-		HeapFree(GetProcessHeap(), 0, m_szMsg);
-	if (m_wszMsg)
-		HeapFree(GetProcessHeap(), 0, m_wszMsg);
-}
-
-const char* Win32Error::what() const noexcept
-{
-	if (!m_szMsg)
-		FormatMessageA(
-		    FORMAT_MESSAGE_ALLOCATE_BUFFER
-		    |FORMAT_MESSAGE_FROM_SYSTEM
-		    |FORMAT_MESSAGE_FROM_HMODULE
-		    |FORMAT_MESSAGE_IGNORE_INSERTS,
-		    hModule,
-		    code,
-		    MAKELANGID(LANG_ENGLISH, SUBLANG_ENGLISH_US),
-		    (char*)&m_szMsg,
-		    0, nullptr);
-	return m_szMsg? m_szMsg: "An unknown error occurred";
-}
-
-const wchar_t* Win32Error::What() const noexcept
-{
-	if (!m_wszMsg)
-		FormatMessageW(
-		    FORMAT_MESSAGE_ALLOCATE_BUFFER
-		    |FORMAT_MESSAGE_FROM_SYSTEM
-		    |FORMAT_MESSAGE_FROM_HMODULE
-		    |FORMAT_MESSAGE_IGNORE_INSERTS,
-		    hModule,
-		    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, GetModuleHandle(L"wininet.dll"));
-
-	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 (!InternetGetLastResponseInfoW(&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;
-}
-
 std::optional<Library> Library::Maybe(const wchar_t* const lib) noexcept
 {
 	HMODULE hModule = LoadLibraryW(lib);
-- 
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