DDrawCompat/DDrawCompat/CompatRegistry.cpp

#include <cassert>
#include <cstring>
#include <map>

#include <atlstr.h>

#include "CompatRegistry.h"
#include "DDrawLog.h"
#include "Hook.h"

namespace
{
	struct RegistryKey
	{
		HKEY key;
		CStringW subKey;
		CStringW value;

		RegistryKey(HKEY key, CStringW subKey, CStringW value) : key(key), subKey(subKey), value(value) {}

		bool operator<(const RegistryKey& rhs) const
		{
			if (key < rhs.key) { return true; }
			if (key > rhs.key) { return false; }
			const int subKeyComp = subKey.CompareNoCase(rhs.subKey);
			if (subKeyComp < 0) { return true; }
			if (subKeyComp > 0) { return false; }
			return value.CompareNoCase(rhs.value) < 0;
		}

		bool operator==(const RegistryKey& rhs) const
		{
			return key == rhs.key &&
				0 == subKey.CompareNoCase(rhs.subKey) &&
				0 == value.CompareNoCase(rhs.value);
		}
	};

	std::map<RegistryKey, DWORD> g_registryOverride;

	LSTATUS WINAPI regGetValueW(HKEY hkey, LPCWSTR lpSubKey, LPCWSTR lpValue, 
		DWORD dwFlags, LPDWORD pdwType, PVOID pvData, LPDWORD pcbData)
	{
		Compat::LogEnter("regGetValueW", hkey, lpSubKey, lpValue, dwFlags, pdwType, pvData, pcbData);
		LSTATUS result = ERROR_SUCCESS;

		const auto it = hkey && lpSubKey && lpValue && (dwFlags & RRF_RT_REG_DWORD)
			? g_registryOverride.find(RegistryKey(hkey, lpSubKey, lpValue))
			: g_registryOverride.end();

		if (it != g_registryOverride.end())
		{
			if (pdwType)
			{
				*pdwType = REG_DWORD;
			}

			if (pvData)
			{
				if (!pcbData)
				{
					result = ERROR_INVALID_PARAMETER;
				}
				else if (*pcbData >= sizeof(DWORD))
				{
					std::memcpy(pvData, &it->second, sizeof(DWORD));
				}
				else
				{
					result = ERROR_MORE_DATA;
				}
			}

			if (pcbData)
			{
				*pcbData = sizeof(DWORD);
			}
		}
		else
		{
			result = CALL_ORIG_FUNC(RegGetValueW)(hkey, lpSubKey, lpValue, dwFlags, pdwType, pvData, pcbData);
		}

	 	Compat::LogLeave("regGetValueW", hkey, lpSubKey, lpValue, dwFlags, pdwType, pvData, pcbData) << result;
		return result;
	}
}

namespace CompatRegistry
{
	void installHooks()
	{
		HOOK_FUNCTION(KernelBase, RegGetValueW, regGetValueW);
	}

	void setValue(HKEY key, const char* subKey, const char* valueName, DWORD value)
	{
		assert(key && subKey && valueName);
		g_registryOverride[RegistryKey(key, subKey, valueName)] = value;
	}
}