components/dotnet-registry/src/main/java/npanday/registry/impl/WinRegistry.java

package npanday.registry.impl;

import npanday.registry.WindowsRegistryAccessException;
import npanday.registry.WindowsRegistryAccessProvider;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.prefs.Preferences;

public class WinRegistry
    implements WindowsRegistryAccessProvider
{
    public static final int HKEY_CURRENT_USER = 0x80000001;

    public static final int HKEY_LOCAL_MACHINE = 0x80000002;

    public static final int REG_SUCCESS = 0;

    private static final int KEY_ALL_ACCESS = 0xf003f;

    private static final int KEY_READ = 0x20019;

    private static Preferences userRoot = Preferences.userRoot();

    private static Preferences systemRoot = Preferences.systemRoot();

    private static Class<? extends Preferences> userClass = userRoot.getClass();

    private static Method regOpenKey = null;

    private static Method regCloseKey = null;

    private static Method regQueryValueEx = null;

    private static Method regEnumValue = null;

    private static Method regQueryInfoKey = null;

    private static Method regEnumKeyEx = null;

    private static Method regCreateKeyEx = null;

    private static Method regSetValueEx = null;

    private static Method regDeleteKey = null;

    private static Method regDeleteValue = null;

    static
    {
        try
        {
            regOpenKey = userClass.getDeclaredMethod(
                "WindowsRegOpenKey", new Class[]{ int.class, byte[].class, int.class }
            );
            regOpenKey.setAccessible( true );
            regCloseKey = userClass.getDeclaredMethod( "WindowsRegCloseKey", new Class[]{ int.class } );
            regCloseKey.setAccessible( true );
            regQueryValueEx = userClass.getDeclaredMethod(
                "WindowsRegQueryValueEx", new Class[]{ int.class, byte[].class }
            );
            regQueryValueEx.setAccessible( true );
            regEnumValue = userClass.getDeclaredMethod(
                "WindowsRegEnumValue", new Class[]{ int.class, int.class, int.class }
            );
            regEnumValue.setAccessible( true );
            regQueryInfoKey = userClass.getDeclaredMethod( "WindowsRegQueryInfoKey1", new Class[]{ int.class } );
            regQueryInfoKey.setAccessible( true );
            regEnumKeyEx = userClass.getDeclaredMethod(
                "WindowsRegEnumKeyEx", new Class[]{ int.class, int.class, int.class }
            );
            regEnumKeyEx.setAccessible( true );
            regCreateKeyEx = userClass.getDeclaredMethod(
                "WindowsRegCreateKeyEx", new Class[]{ int.class, byte[].class }
            );
            regCreateKeyEx.setAccessible( true );
            regSetValueEx = userClass.getDeclaredMethod(
                "WindowsRegSetValueEx", new Class[]{ int.class, byte[].class, byte[].class }
            );
            regSetValueEx.setAccessible( true );
            regDeleteValue = userClass.getDeclaredMethod(
                "WindowsRegDeleteValue", new Class[]{ int.class, byte[].class }
            );
            regDeleteValue.setAccessible( true );
            regDeleteKey = userClass.getDeclaredMethod(
                "WindowsRegDeleteKey", new Class[]{
                int.class, byte[].class
            }
            );
            regDeleteKey.setAccessible( true );
        }
        catch ( Exception e )
        {
            e.printStackTrace();
        }
    }

    public WinRegistry()
    {
    }

    /**
     * Read a value from key and value name
     *
     * @param hkey      HKEY_CURRENT_USER/HKEY_LOCAL_MACHINE
     * @param key
     * @param valueName
     * @return the value
     * @throws IllegalArgumentException
     * @throws IllegalAccessException
     * @throws java.lang.reflect.InvocationTargetException
     *
     */
    public static String readString( int hkey, String key, String valueName ) throws
        IllegalArgumentException,
        IllegalAccessException,
        InvocationTargetException
    {
        if ( hkey == HKEY_LOCAL_MACHINE )
        {
            return readString( systemRoot, hkey, key, valueName );
        }
        else if ( hkey == HKEY_CURRENT_USER )
        {
            return readString( userRoot, hkey, key, valueName );
        }
        else
        {
            throw new IllegalArgumentException( "hkey=" + hkey );
        }
    }

    /**
     * Read value(s) and value name(s) form given key
     *
     * @param hkey HKEY_CURRENT_USER/HKEY_LOCAL_MACHINE
     * @param key
     * @return the value name(s) plus the value(s)
     * @throws IllegalArgumentException
     * @throws IllegalAccessException
     * @throws java.lang.reflect.InvocationTargetException
     *
     */
    public static Map<String, String> readStringValues( int hkey, String key ) throws
        IllegalArgumentException,
        IllegalAccessException,
        InvocationTargetException
    {
        if ( hkey == HKEY_LOCAL_MACHINE )
        {
            return readStringValues( systemRoot, hkey, key );
        }
        else if ( hkey == HKEY_CURRENT_USER )
        {
            return readStringValues( userRoot, hkey, key );
        }
        else
        {
            throw new IllegalArgumentException( "hkey=" + hkey );
        }
    }

    /**
     * Read the value name(s) from a given key
     *
     * @param hkey HKEY_CURRENT_USER/HKEY_LOCAL_MACHINE
     * @param key
     * @return the value name(s)
     * @throws IllegalArgumentException
     * @throws IllegalAccessException
     * @throws java.lang.reflect.InvocationTargetException
     *
     */
    public static List<String> readStringSubKeys( int hkey, String key ) throws
        IllegalArgumentException,
        IllegalAccessException,
        InvocationTargetException
    {
        if ( hkey == HKEY_LOCAL_MACHINE )
        {
            return readStringSubKeys( systemRoot, hkey, key );
        }
        else if ( hkey == HKEY_CURRENT_USER )
        {
            return readStringSubKeys( userRoot, hkey, key );
        }
        else
        {
            throw new IllegalArgumentException( "hkey=" + hkey );
        }
    }

    /**
     * Create a key
     *
     * @param hkey HKEY_CURRENT_USER/HKEY_LOCAL_MACHINE
     * @param key
     * @throws IllegalArgumentException
     * @throws IllegalAccessException
     * @throws java.lang.reflect.InvocationTargetException
     *
     */
    public static void createKey( int hkey, String key ) throws
        IllegalArgumentException,
        IllegalAccessException,
        InvocationTargetException
    {
        int[] ret;
        if ( hkey == HKEY_LOCAL_MACHINE )
        {
            ret = createKey( systemRoot, hkey, key );
            regCloseKey.invoke( systemRoot, new Object[]{ new Integer( ret[0] ) } );
        }
        else if ( hkey == HKEY_CURRENT_USER )
        {
            ret = createKey( userRoot, hkey, key );
            regCloseKey.invoke( userRoot, new Object[]{ new Integer( ret[0] ) } );
        }
        else
        {
            throw new IllegalArgumentException( "hkey=" + hkey );
        }
        if ( ret[1] != REG_SUCCESS )
        {
            throw new IllegalArgumentException( "rc=" + ret[1] + "  key=" + key );
        }
    }

    /**
     * Write a value in a given key/value name
     *
     * @param hkey
     * @param key
     * @param valueName
     * @param value
     * @throws IllegalArgumentException
     * @throws IllegalAccessException
     * @throws java.lang.reflect.InvocationTargetException
     *
     */
    public static void writeStringValue( int hkey, String key, String valueName, String value ) throws
        IllegalArgumentException,
        IllegalAccessException,
        InvocationTargetException
    {
        if ( hkey == HKEY_LOCAL_MACHINE )
        {
            writeStringValue( systemRoot, hkey, key, valueName, value );
        }
        else if ( hkey == HKEY_CURRENT_USER )
        {
            writeStringValue( userRoot, hkey, key, valueName, value );
        }
        else
        {
            throw new IllegalArgumentException( "hkey=" + hkey );
        }
    }

    /**
     * Delete a given key
     *
     * @param hkey
     * @param key
     * @throws IllegalArgumentException
     * @throws IllegalAccessException
     * @throws java.lang.reflect.InvocationTargetException
     *
     */
    public static void deleteKey( int hkey, String key ) throws
        IllegalArgumentException,
        IllegalAccessException,
        InvocationTargetException
    {
        int rc = -1;
        if ( hkey == HKEY_LOCAL_MACHINE )
        {
            rc = deleteKey( systemRoot, hkey, key );
        }
        else if ( hkey == HKEY_CURRENT_USER )
        {
            rc = deleteKey( userRoot, hkey, key );
        }
        if ( rc != REG_SUCCESS )
        {
            throw new IllegalArgumentException( "rc=" + rc + "  key=" + key );
        }
    }

    /**
     * delete a value from a given key/value name
     *
     * @param hkey
     * @param key
     * @param value
     * @throws IllegalArgumentException
     * @throws IllegalAccessException
     * @throws java.lang.reflect.InvocationTargetException
     *
     */
    public static void deleteValue( int hkey, String key, String value ) throws
        IllegalArgumentException,
        IllegalAccessException,
        InvocationTargetException
    {
        int rc = -1;
        if ( hkey == HKEY_LOCAL_MACHINE )
        {
            rc = deleteValue( systemRoot, hkey, key, value );
        }
        else if ( hkey == HKEY_CURRENT_USER )
        {
            rc = deleteValue( userRoot, hkey, key, value );
        }
        if ( rc != REG_SUCCESS )
        {
            throw new IllegalArgumentException( "rc=" + rc + "  key=" + key + "  value=" + value );
        }
    }

    // =====================

    private static int deleteValue( Preferences root, int hkey, String key, String value ) throws
        IllegalArgumentException,
        IllegalAccessException,
        InvocationTargetException
    {
        int[] handles = (int[]) regOpenKey.invoke(
            root, new Object[]{
            new Integer( hkey ), toCstr( key ), new Integer( KEY_ALL_ACCESS )
        }
        );
        if ( handles[1] != REG_SUCCESS )
        {
            return handles[1];  // can be REG_NOTFOUND, REG_ACCESSDENIED
        }
        int rc = (
            (Integer) regDeleteValue.invoke(
                root, new Object[]{
                new Integer( handles[0] ), toCstr( value )
            }
            )
        ).intValue();
        regCloseKey.invoke( root, new Object[]{ new Integer( handles[0] ) } );
        return rc;
    }

    private static int deleteKey( Preferences root, int hkey, String key ) throws
        IllegalArgumentException,
        IllegalAccessException,
        InvocationTargetException
    {
        int rc = (
            (Integer) regDeleteKey.invoke(
                root, new Object[]{ new Integer( hkey ), toCstr( key ) }
            )
        ).intValue();
        return rc;  // can REG_NOTFOUND, REG_ACCESSDENIED, REG_SUCCESS
    }

    private static String readString( Preferences root, int hkey, String key, String value ) throws
        IllegalArgumentException,
        IllegalAccessException,
        InvocationTargetException
    {
        int[] handles = (int[]) regOpenKey.invoke(
            root, new Object[]{
            new Integer( hkey ), toCstr( key ), new Integer( KEY_READ )
        }
        );
        if ( handles[1] != REG_SUCCESS )
        {
            return null;
        }
        byte[] valb = (byte[]) regQueryValueEx.invoke(
            root, new Object[]{ new Integer( handles[0] ), toCstr( value ) }
        );
        regCloseKey.invoke( root, new Object[]{ new Integer( handles[0] ) } );
        return ( valb != null ? new String( valb ).trim() : null );
    }

    private static Map<String, String> readStringValues( Preferences root, int hkey, String key ) throws
        IllegalArgumentException,
        IllegalAccessException,
        InvocationTargetException
    {
        HashMap<String, String> results = new HashMap<String, String>();
        int[] handles = (int[]) regOpenKey.invoke(
            root, new Object[]{
            new Integer( hkey ), toCstr( key ), new Integer( KEY_READ )
        }
        );
        if ( handles[1] != REG_SUCCESS )
        {
            return null;
        }
        int[] info = (int[]) regQueryInfoKey.invoke( root, new Object[]{ new Integer( handles[0] ) } );

        int count = info[2]; // count
        int maxlen = info[3]; // value length max
        for ( int index = 0; index < count; index++ )
        {
            byte[] name = (byte[]) regEnumValue.invoke(
                root, new Object[]{
                new Integer( handles[0] ), new Integer( index ), new Integer( maxlen + 1 )
            }
            );
            String value = readString( hkey, key, new String( name ) );
            results.put( new String( name ).trim(), value );
        }
        regCloseKey.invoke( root, new Object[]{ new Integer( handles[0] ) } );
        return results;
    }

    private static List<String> readStringSubKeys( Preferences root, int hkey, String key ) throws
        IllegalArgumentException,
        IllegalAccessException,
        InvocationTargetException
    {
        List<String> results = new ArrayList<String>();
        int[] handles = (int[]) regOpenKey.invoke(
            root, new Object[]{
            new Integer( hkey ), toCstr( key ), new Integer( KEY_READ )
        }
        );
        if ( handles[1] != REG_SUCCESS )
        {
            return null;
        }
        int[] info = (int[]) regQueryInfoKey.invoke( root, new Object[]{ new Integer( handles[0] ) } );

        int count = info[2]; // count
        int maxlen = info[3]; // value length max
        for ( int index = 0; index < count; index++ )
        {
            byte[] name = (byte[]) regEnumKeyEx.invoke(
                root, new Object[]{
                new Integer( handles[0] ), new Integer( index ), new Integer( maxlen + 1 )
            }
            );
            results.add( new String( name ).trim() );
        }
        regCloseKey.invoke( root, new Object[]{ new Integer( handles[0] ) } );
        return results;
    }

    private static int[] createKey( Preferences root, int hkey, String key ) throws
        IllegalArgumentException,
        IllegalAccessException,
        InvocationTargetException
    {
        return (int[]) regCreateKeyEx.invoke( root, new Object[]{ new Integer( hkey ), toCstr( key ) } );
    }

    private static void writeStringValue(
        Preferences root, int hkey, String key, String valueName, String value ) throws
        IllegalArgumentException,
        IllegalAccessException,
        InvocationTargetException
    {
        int[] handles = (int[]) regOpenKey.invoke(
            root, new Object[]{
            new Integer( hkey ), toCstr( key ), new Integer( KEY_ALL_ACCESS )
        }
        );

        regSetValueEx.invoke( root, new Object[]{ new Integer( handles[0] ), toCstr( valueName ), toCstr( value ) } );
        regCloseKey.invoke( root, new Object[]{ new Integer( handles[0] ) } );
    }

    // utility
    private static byte[] toCstr( String str )
    {
        byte[] result = new byte[str.length() + 1];

        for ( int i = 0; i < str.length(); i++ )
        {
            result[i] = (byte) str.charAt( i );
        }
        result[str.length()] = 0;
        return result;
    }

    public String getValue(
        RegistryHKey registryHKey, String key, String valueName ) throws WindowsRegistryAccessException
    {
        try
        {
            return WinRegistry.readString(
                registryHKey.getHKey(), key, valueName
            );
        }
        catch ( InvocationTargetException e )
        {
            throw new WindowsRegistryAccessException(
                "NPANDAY-117-000: Error while retrieving a windows registry value", e
            );
        }
        catch ( IllegalAccessException e )
        {
            throw new WindowsRegistryAccessException(
                "NPANDAY-117-001: Error while retrieving a windows registry value", e
            );
        }
    }
}