package org.apidesign.impl.security.extension;

 import org.apidesign.api.security.Digest;

 import java.nio.ByteBuffer;

 import java.security.MessageDigest;

 import java.security.NoSuchAlgorithmException;

 import java.security.Provider;

 import java.security.Security;

 import java.util.Collections;

 import java.util.List;

 import java.util.Map;

 /**

  *

  * @author Jaroslav Tulach <jaroslav.tulach@apidesign.org>

  */

 // BEGIN: day.end.bridges.BridgeToOld

 public final class BridgeToOld extends Provider {

     public BridgeToOld() {

         super("spi.Digestor", 1.0, "");

         Security.addProvider(this);

     }

     // BEGIN: day.end.bridges.cycle

     private ThreadLocal<Boolean> searching = new ThreadLocal<Boolean>();

     final boolean isSearching() {

         return Boolean.TRUE.equals(searching.get());

     }

     @Override

     public synchronized Service getService(String type, String algorithm) {

         Boolean prev = searching.get();

         try {

             searching.set(Boolean.TRUE);

             if ("MessageDigest".equals(type)) {

                 Digest dig = Digest.getInstance(algorithm);

                 if (dig != null) {

                     return new ServiceImpl(

                         dig, this, type, algorithm, "", 

                         Collections.<String>emptyList(), 

                         Collections.<String,String>emptyMap());

                 }

             }

             return null;

         } finally {

             searching.set(prev);

         }

     }

     // END: day.end.bridges.cycle

     private static class ServiceImpl<Data> extends Service {

         Digest dig;

         public ServiceImpl(Digest dig, Provider provider, 

             String type, String algorithm, String className, 

             List<String> aliases, Map<String, String> attributes

         ) {

             super(

                 provider, type, algorithm, className, aliases, attributes

             );

             this.dig = dig;

         }

         @Override

         public Object newInstance(Object constructorParameter) 

         throws NoSuchAlgorithmException {

             return new MessageDigest(getAlgorithm()) {

                 private byte[] res;

                 @Override

                 protected void engineUpdate(byte input) {

                     ByteBuffer bb = ByteBuffer.wrap(new byte[] { input });

                     res = dig.digest(bb);

                 }

                 @Override

                 protected void engineUpdate(

                     byte[] input, int offset, int len

                 ) {

                     ByteBuffer bb = ByteBuffer.wrap(input);

                     bb.position(offset);

                     bb.limit(offset + len);

                     res = dig.digest(bb);

                 }

                 @Override

                 protected byte[] engineDigest() {

                     return res;

                 }

                 @Override

                 protected void engineReset() {

                     dig = Digest.getInstance(getAlgorithm());

                 }

             };

         }

     }

 }

 // END: day.end.bridges.BridgeToOld