/*
 * Copyright (c) 2001-2008 Caucho Technology, Inc.  All rights reserved.
 *
 * The Apache Software License, Version 1.1
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Caucho Technology (http://www.caucho.com/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "Burlap", "Resin", and "Caucho" must not be used to
 *    endorse or promote products derived from this software without prior
 *    written permission. For written permission, please contact
 *    info@caucho.com.
 *
 * 5. Products derived from this software may not be called "Resin"
 *    nor may "Resin" appear in their names without prior written
 *    permission of Caucho Technology.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL CAUCHO TECHNOLOGY OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * @author Scott Ferguson
 */

package com.caucho.hessian.io;

import java.io.IOException;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.HashMap;
import java.util.logging.Level;
import java.util.logging.Logger;

import com.caucho.hessian.io.FieldDeserializer2FactoryUnsafe.NullFieldDeserializer;

import sun.misc.Unsafe;

Serializing an object for known object types.
/**
 * Serializing an object for known object types.
 */
public class UnsafeDeserializer extends AbstractMapDeserializer {
  private static final Logger log
    = Logger.getLogger(JavaDeserializer.class.getName());

  private static boolean _isEnabled;
  @SuppressWarnings("restriction")
  private static Unsafe _unsafe;

  private Class<?> _type;
  private HashMap<String,FieldDeserializer2> _fieldMap;
  private Method _readResolve;

  public UnsafeDeserializer(Class<?> cl, FieldDeserializer2Factory fieldFactory)
  {
    _type = cl;
    _fieldMap = getFieldMap(cl, fieldFactory);

    _readResolve = getReadResolve(cl);

    if (_readResolve != null) {
      _readResolve.setAccessible(true);
    }
  }
  
  public static boolean isEnabled()
  {
    return _isEnabled;
  }

  @Override
  public Class<?> getType()
  {
    return _type;
  }

  @Override
  public boolean isReadResolve()
  {
    return _readResolve != null;
  }

  public Object readMap(AbstractHessianInput in)
    throws IOException
  {
    try {
      Object obj = instantiate();

      return readMap(in, obj);
    } catch (IOException e) {
      throw e;
    } catch (RuntimeException e) {
      throw e;
    } catch (Exception e) {
      throw new IOExceptionWrapper(_type.getName() + ":" + e.getMessage(), e);
    }
  }
  
  @Override
  public Object []createFields(int len)
  {
    return new FieldDeserializer2[len];
  }

  public Object createField(String name)
  {
    Object reader = _fieldMap.get(name);
    
    if (reader == null)
      reader = NullFieldDeserializer.DESER;
    
    return reader;
  }

  @Override
  public Object readObject(AbstractHessianInput in,
                           Object []fields)
    throws IOException
  {
    try {
      Object obj = instantiate();

      return readObject(in, obj, (FieldDeserializer2 []) fields);
    } catch (IOException e) {
      throw e;
    } catch (RuntimeException e) {
      throw e;
    } catch (Exception e) {
      throw new IOExceptionWrapper(_type.getName() + ":" + e.getMessage(), e);
    }
  }

  @Override
  public Object readObject(AbstractHessianInput in,
                           String []fieldNames)
    throws IOException
  {
    try {
      Object obj = instantiate();

      return readObject(in, obj, fieldNames);
    } catch (IOException e) {
      throw e;
    } catch (RuntimeException e) {
      throw e;
    } catch (Exception e) {
      throw new IOExceptionWrapper(_type.getName() + ":" + e.getMessage(), e);
    }
  }

  
Returns the readResolve method
/**
   * Returns the readResolve method
   */
  protected Method getReadResolve(Class<?> cl)
  {
    for (; cl != null; cl = cl.getSuperclass()) {
      Method []methods = cl.getDeclaredMethods();

      for (int i = 0; i < methods.length; i++) {
        Method method = methods[i];

        if (method.getName().equals("readResolve")
            && method.getParameterTypes().length == 0)
          return method;
      }
    }

    return null;
  }

  public Object readMap(AbstractHessianInput in, Object obj)
    throws IOException
  {
    try {
      int ref = in.addRef(obj);

      while (! in.isEnd()) {
        Object key = in.readObject();

        FieldDeserializer2 deser = (FieldDeserializer2) _fieldMap.get(key);

        if (deser != null)
          deser.deserialize(in, obj);
        else
          in.readObject();
      }

      in.readMapEnd();

      Object resolve = resolve(in, obj);

      if (obj != resolve)
        in.setRef(ref, resolve);

      return resolve;
    } catch (IOException e) {
      throw e;
    } catch (Exception e) {
      throw new IOExceptionWrapper(e);
    }
  }

  public Object readObject(AbstractHessianInput in,
                           Object obj,
                           FieldDeserializer2 []fields)
    throws IOException
  {
    try {
      int ref = in.addRef(obj);

      for (FieldDeserializer2 reader : fields) {
        reader.deserialize(in, obj);
      }

      Object resolve = resolve(in, obj);

      if (obj != resolve)
        in.setRef(ref, resolve);

      return resolve;
    } catch (IOException e) {
      throw e;
    } catch (Exception e) {
      throw new IOExceptionWrapper(obj.getClass().getName() + ":" + e, e);
    }
  }

  public Object readObject(AbstractHessianInput in,
                           Object obj,
                           String []fieldNames)
    throws IOException
  {
    try {
      int ref = in.addRef(obj);

      for (String fieldName : fieldNames) {
        FieldDeserializer2 reader = _fieldMap.get(fieldName);
        
        if (reader != null)
          reader.deserialize(in, obj);
        else
          in.readObject();
      }

      Object resolve = resolve(in, obj);

      if (obj != resolve)
        in.setRef(ref, resolve);

      return resolve;
    } catch (IOException e) {
      throw e;
    } catch (Exception e) {
      throw new IOExceptionWrapper(obj.getClass().getName() + ":" + e, e);
    }
  }

  protected Object resolve(AbstractHessianInput in, Object obj)
    throws Exception
  {
    // if there's a readResolve method, call it
    try {
      if (_readResolve != null)
        return _readResolve.invoke(obj, new Object[0]);
    } catch (InvocationTargetException e) {
      if (e.getCause() instanceof Exception)
        throw (Exception) e.getCause();
      else
        throw e;
    }

    return obj;
  }

  @SuppressWarnings("restriction")
  protected Object instantiate()
    throws Exception
  {
    return _unsafe.allocateInstance(_type);
  }

  
Creates a map of the classes fields.
/**
   * Creates a map of the classes fields.
   */
  protected HashMap<String,FieldDeserializer2> 
  getFieldMap(Class<?> cl, FieldDeserializer2Factory fieldFactory)
  {
    HashMap<String,FieldDeserializer2> fieldMap
      = new HashMap<String,FieldDeserializer2>();
    
    for (; cl != null; cl = cl.getSuperclass()) {
      Field []fields = cl.getDeclaredFields();
      for (int i = 0; i < fields.length; i++) {
        Field field = fields[i];

        if (Modifier.isTransient(field.getModifiers())
            || Modifier.isStatic(field.getModifiers()))
          continue;
        else if (fieldMap.get(field.getName()) != null)
          continue;

        /*
        // XXX: could parameterize the handler to only deal with public
        try {
          field.setAccessible(true);
        } catch (Throwable e) {
          e.printStackTrace();
        }
        */

        FieldDeserializer2 deser = fieldFactory.create(field);

        fieldMap.put(field.getName(), deser);
      }
    }

    return fieldMap;
  }

  static void logDeserializeError(Field field, Object obj, Object value,
                                  Throwable e)
    throws IOException
  {
    String fieldName = (field.getDeclaringClass().getName()
                        + "." + field.getName());

    if (e instanceof HessianFieldException)
      throw (HessianFieldException) e;
    else if (e instanceof IOException)
      throw new HessianFieldException(fieldName + ": " + e.getMessage(), e);

    if (value != null)
      throw new HessianFieldException(fieldName + ": " + value.getClass().getName() + " (" + value + ")"
                                      + " cannot be assigned to '" + field.getType().getName() + "'", e);
    else
       throw new HessianFieldException(fieldName + ": " + field.getType().getName() + " cannot be assigned from null", e);
  }

  static {
    boolean isEnabled = false;

    try {
      Class<?> unsafe = Class.forName("sun.misc.Unsafe");
      Field theUnsafe = null;
      for (Field field : unsafe.getDeclaredFields()) {
        if (field.getName().equals("theUnsafe"))
          theUnsafe = field;
      }

      if (theUnsafe != null) {
        theUnsafe.setAccessible(true);
        _unsafe = (Unsafe) theUnsafe.get(null);
      }

      isEnabled = _unsafe != null;

      String unsafeProp = System.getProperty("com.caucho.hessian.unsafe");

      if ("false".equals(unsafeProp))
        isEnabled = false;
    } catch (Throwable e) {
      log.log(Level.FINER, e.toString(), e);
    }

    _isEnabled = isEnabled;
  }
}