/*
 * 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.alibaba.com.caucho.hessian.io;

import com.alibaba.com.caucho.hessian.io.FieldDeserializer2FactoryUnsafe.NullFieldDeserializer;
import sun.misc.Unsafe;

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;

/**
 * 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;

    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;
    }

    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;
    }

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

    @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
     */
    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.
     */
    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;
    }
}