Method FindJavaFromRegistryKey

launcher/java/JavaUtils.cpp:197–271

#if defined(Q_OS_WIN32)
QList<JavaInstallPtr> JavaUtils::FindJavaFromRegistryKey(DWORD keyType, QString keyName, QString keyJavaDir, QString subkeySuffix)
{
    QList<JavaInstallPtr> javas;

    QString archType = "unknown";
    if (keyType == KEY_WOW64_64KEY)
        archType = "64";
    else if (keyType == KEY_WOW64_32KEY)
        archType = "32";

    HKEY jreKey;
    if (RegOpenKeyExW(HKEY_LOCAL_MACHINE, keyName.toStdWString().c_str(), 0,
                      KEY_READ | keyType | KEY_ENUMERATE_SUB_KEYS, &jreKey) == ERROR_SUCCESS)
    {
        // Read the current type version from the registry.
        // This will be used to find any key that contains the JavaHome value.

        WCHAR subKeyName[255];
        DWORD subKeyNameSize, numSubKeys, retCode;

        // Get the number of subkeys
        RegQueryInfoKeyW(jreKey, NULL, NULL, NULL, &numSubKeys, NULL, NULL, NULL, NULL, NULL,
                        NULL, NULL);

        // Iterate until RegEnumKeyEx fails
        if (numSubKeys > 0)
        {
            for (DWORD i = 0; i < numSubKeys; i++)
            {
                subKeyNameSize = 255;
                retCode = RegEnumKeyExW(jreKey, i, subKeyName, &subKeyNameSize, NULL, NULL, NULL,
                                        NULL);
                QString newSubkeyName = QString::fromWCharArray(subKeyName);
                if (retCode == ERROR_SUCCESS)
                {
                    // Now open the registry key for the version that we just got.
                    QString newKeyName = keyName + "\\" + newSubkeyName + subkeySuffix;

                    HKEY newKey;
                    if (RegOpenKeyExW(HKEY_LOCAL_MACHINE, newKeyName.toStdWString().c_str(), 0,
                                      KEY_READ | KEY_WOW64_64KEY, &newKey) == ERROR_SUCCESS)
                    {
                        // Read the JavaHome value to find where Java is installed.
                        DWORD valueSz = 0;
                        if (RegQueryValueExW(newKey, keyJavaDir.toStdWString().c_str(), NULL, NULL, NULL,
                                             &valueSz) == ERROR_SUCCESS)
                        {
                            WCHAR *value = new WCHAR[valueSz];
                            RegQueryValueExW(newKey, keyJavaDir.toStdWString().c_str(), NULL, NULL, (BYTE *)value,
                                             &valueSz);

                            QString newValue = QString::fromWCharArray(value);
                            delete [] value;

                            // Now, we construct the version object and add it to the list.
                            JavaInstallPtr javaVersion(new JavaInstall());

                            javaVersion->id = newSubkeyName;