Added support for WPT installation in atypical locations.

Addresses #118.

UIforETW/UIforETWDlg.cpp

@@ -400,18 +400,40 @@ BOOL CUIforETWDlg::OnInitDialog()
 	systemDrive_ = static_cast<char>(windowsDir_[0]);
 	systemDrive_ += ":\\";
 
-	// The WPT 8.1 installer is always a 32-bit installer, so we look for it in
-	// ProgramFilesX86, on 32-bit and 64-bit operating systems.
-	wchar_t* progFilesx86Dir = nullptr;
-	if (!SUCCEEDED(SHGetKnownFolderPath(FOLDERID_ProgramFilesX86, 0, NULL, &progFilesx86Dir)))
-		std::terminate();
-	windowsKitsDir_ = progFilesx86Dir;
-	CoTaskMemFree(progFilesx86Dir);
-	progFilesx86Dir = nullptr;
 
-	windowsKitsDir_ += L"\\Windows Kits\\";
-	wpt81Dir_ = windowsKitsDir_ + L"8.1\\Windows Performance Toolkit\\";
-	wpt10Dir_ = windowsKitsDir_ + L"10\\Windows Performance Toolkit\\";
+	// The WPT installer is always a 32-bit installer, so we look for it in
+	// ProgramFilesX86 / WOW6432Node, on 32-bit and 64-bit operating systems.
+	wpt81Dir_ = ReadRegistryString(HKEY_LOCAL_MACHINE, L"SOFTWARE\\Microsoft\\Microsoft SDKs\\Windows\\v8.1", L"InstallationFolder", true);
+	wpt10Dir_ = ReadRegistryString(HKEY_LOCAL_MACHINE, L"SOFTWARE\\Microsoft\\Microsoft SDKs\\Windows\\v10.0", L"InstallationFolder", true);
+	if (!wpt81Dir_.empty())
+	{
+		EnsureEndsWithDirSeparator(wpt81Dir_);
+		wpt81Dir_ += L"Windows Performance Toolkit\\";
+	}
+	if (!wpt10Dir_.empty())
+	{
+		EnsureEndsWithDirSeparator(wpt10Dir_);
+		wpt10Dir_ += L"Windows Performance Toolkit\\";
+	}
+
+	// If the registry entries were unavailable, fall back to assuming their installation directory.
+	if (wpt81Dir_.empty() || wpt10Dir_.empty())
+	{
+		wchar_t* progFilesx86Dir = nullptr;
+		if (!SUCCEEDED(SHGetKnownFolderPath(FOLDERID_ProgramFilesX86, 0, nullptr, &progFilesx86Dir)))
+			std::terminate();
+		std::wstring windowsKitsDir = progFilesx86Dir;
+		CoTaskMemFree(progFilesx86Dir);
+		windowsKitsDir += L"\\Windows Kits\\";
+		if (wpt81Dir_.empty())
+		{
+			wpt81Dir_ = windowsKitsDir + L"8.1\\Windows Performance Toolkit\\";
+		}
+		if (wpt10Dir_.empty())
+		{
+			wpt10Dir_ = windowsKitsDir + L"10\\Windows Performance Toolkit\\";
+		}
+	}
 
 	auto xperfVersion = GetFileVersion(GetXperfPath());
 	const int64_t requiredXperfVersion = (10llu << 48) + 0 + (10586llu << 16) + (15llu << 0);

UIforETW/UIforETWDlg.h

@@ -152,7 +152,6 @@ class CUIforETWDlg : public CDialog
 	// this string object, so don't change it without adding synchronization.
 	std::wstring traceDir_;
 	std::wstring tempTraceDir_;
-	std::wstring windowsKitsDir_; // C:\\Program Files (x86)\\Windows Kits
 	std::wstring wpt81Dir_; // This points to the WPT 8.1 directory if it exists, else nothing.
 	std::wstring wpt10Dir_; // If WPT 10 isn't installed UIforETW will exit.
 	std::wstring wpa81Path_;

UIforETW/Utility.cpp

@@ -298,6 +298,47 @@ std::wstring ConvertToCRLF(const std::wstring& input)
 	return result;
 }
 
+std::wstring ReadRegistryString(HKEY root, const std::wstring& subkey, const std::wstring& valueName, bool force32Bit)
+{
+	std::wstring value;
+	const DWORD flags = RRF_RT_REG_SZ | RRF_RT_REG_EXPAND_SZ | RRF_ZEROONFAILURE;
+
+	REGSAM openOptions = KEY_QUERY_VALUE;
+	if (force32Bit)
+	{
+		openOptions |= KEY_WOW64_32KEY;
+	}
+
+	HKEY key;
+	if (::RegOpenKeyExW(root, subkey.c_str(), 0, openOptions, &key) != ERROR_SUCCESS)
+	{
+		return value;
+	}
+
+
+	DWORD bufSize = 50 * sizeof(wchar_t);
+	LSTATUS result = ERROR_MORE_DATA;
+	while (result == ERROR_MORE_DATA)
+	{
+		value.resize(bufSize / sizeof(wchar_t));
+		DWORD type;
+		result = ::RegGetValueW(key, nullptr, valueName.c_str(), flags, &type, const_cast<wchar_t*>(value.data()), &bufSize);
+	}
+	if (result == ERROR_SUCCESS && bufSize > 0)
+	{
+		// remove the space for the NUL teminator written by RegGetValueW
+		value.resize((bufSize / sizeof(wchar_t)) - 1);
+	}
+	else
+	{
+		value.clear();
+	}
+	ATLVERIFY(::RegCloseKey(key) == ERROR_SUCCESS);
+
+	return value;
+}
+
+
 void SetRegistryDWORD(const HKEY root, const std::wstring& subkey, const std::wstring& valueName, const DWORD value) noexcept
 {
 	HKEY key;
@@ -561,6 +602,13 @@ std::wstring CanonicalizePath(const std::wstring& path)
 	return output;
 }
 
+void EnsureEndsWithDirSeparator(std::wstring& path)
+{
+	if (path.back() != '\\')
+	{
+		path.push_back(L'\\');
+	}
+}
 int DeleteOneFile(const HWND hwnd, const std::wstring& path)
 {
 	// {path} uses std::vector list initialization

UIforETW/Utility.h

@@ -35,6 +35,7 @@ std::wstring ConvertToCRLF(const std::wstring& input);
 
 void SetRegistryDWORD(HKEY root, const std::wstring& subkey, const std::wstring& valueName, DWORD value) noexcept;
 void CreateRegistryKey(HKEY root, const std::wstring& subkey, const std::wstring& newKey) noexcept;
+std::wstring ReadRegistryString(HKEY root, const std::wstring& subkey, const std::wstring& valueName, bool force32Bit);
 
 std::wstring GetEditControlText(HWND hwnd);
 std::wstring AnsiToUnicode(const std::string& text);
@@ -62,6 +63,9 @@ std::wstring GetFileExt(const std::wstring& path);
 // Return the path part only, or an empty string if there is no '\'.
 // The '\' character is returned.
 std::wstring GetDirPart(const std::wstring& path);
+// Ensures that a non-empty string ends with '\'.
+// Empty strings are left untouched.
+void EnsureEndsWithDirSeparator(std::wstring& path);
 // Pass this a path and it returns the pre extension part of
 // the file part of the path (which could conceivably be an
 // empty string).