/*******************************************************************************
 * Copyright (c) 2000, 2006 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdi.internal;


import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.eclipse.jdi.internal.jdwp.JdwpCommandPacket;
import org.eclipse.jdi.internal.jdwp.JdwpID;
import org.eclipse.jdi.internal.jdwp.JdwpObjectID;
import org.eclipse.jdi.internal.jdwp.JdwpReplyPacket;

import com.sun.jdi.ArrayType;
import com.sun.jdi.ClassNotLoadedException;
import com.sun.jdi.Field;
import com.sun.jdi.IncompatibleThreadStateException;
import com.sun.jdi.InternalException;
import com.sun.jdi.InvalidTypeException;
import com.sun.jdi.InvocationException;
import com.sun.jdi.Method;
import com.sun.jdi.ObjectCollectedException;
import com.sun.jdi.ObjectReference;
import com.sun.jdi.ReferenceType;
import com.sun.jdi.ThreadReference;
import com.sun.jdi.Type;
import com.sun.jdi.VMDisconnectedException;
import com.sun.jdi.Value;

/**
 * this class implements the corresponding interfaces
 * declared by the JDI specification. See the com.sun.jdi package
 * for more information.
 *
 */
public class ObjectReferenceImpl extends ValueImpl implements ObjectReference {
	/** JDWP Tag. */
	public static final byte tag = JdwpID.OBJECT_TAG;
	
	/** ObjectID of object that corresponds to this reference. */
	private JdwpObjectID fObjectID;
	/**
	 * Cached reference type. This value is safe for caching because
	 * the type of an object never changes.
	 */
	private ReferenceType fReferenceType;
	
	/**
	 * Creates new ObjectReferenceImpl.
	 */
	public ObjectReferenceImpl(VirtualMachineImpl vmImpl, JdwpObjectID objectID) {
		this("ObjectReference", vmImpl, objectID); //$NON-NLS-1$
	}

	/**
	 * Creates new ObjectReferenceImpl.
	 */
	public ObjectReferenceImpl(String description, VirtualMachineImpl vmImpl, JdwpObjectID objectID) {
		super(description, vmImpl);
		fObjectID = objectID;
	}
	
	/**
	 * @returns tag.
	 */
	public byte getTag() {
		return tag;
	}
	
	/**
	 * @return Returns Jdwp Object ID.
	 */
	public JdwpObjectID getObjectID() {
		return fObjectID;
	}

	/** 
	 * Prevents garbage collection for this object. 
	 */
	public void disableCollection() {
		initJdwpRequest();
		try {
			JdwpReplyPacket replyPacket = requestVM(JdwpCommandPacket.OR_DISABLE_COLLECTION, this);
			defaultReplyErrorHandler(replyPacket.errorCode());
		} finally {
			handledJdwpRequest();
		}
	}
	
	/** 
	 * Permits garbage collection for this object. 
	 */
	public void enableCollection() {
		initJdwpRequest();
		try {
			JdwpReplyPacket replyPacket = requestVM(JdwpCommandPacket.OR_ENABLE_COLLECTION, this);
			defaultReplyErrorHandler(replyPacket.errorCode());
		} finally {
			handledJdwpRequest();
		}
	}
	
	/** 
	 * Inner class used to return monitor info.
	 */
	private class MonitorInfo {
		ThreadReferenceImpl owner;
		int entryCount;
		ArrayList waiters;
	}
		
	/** 
	 * @return Returns monitor info.
	 */
	private MonitorInfo monitorInfo() throws IncompatibleThreadStateException {
		if (!virtualMachine().canGetMonitorInfo()) {
			throw new UnsupportedOperationException();
		}
		// Note that this information should not be cached.
		initJdwpRequest();
		try {
			JdwpReplyPacket replyPacket = requestVM(JdwpCommandPacket.OR_MONITOR_INFO, this);
			switch (replyPacket.errorCode()) {
				case JdwpReplyPacket.INVALID_THREAD:
					throw new IncompatibleThreadStateException();
				case JdwpReplyPacket.THREAD_NOT_SUSPENDED:
					throw new IncompatibleThreadStateException();
			}
	
			defaultReplyErrorHandler(replyPacket.errorCode());
			
			DataInputStream replyData = replyPacket.dataInStream();
			MonitorInfo result = new MonitorInfo();
			result.owner = ThreadReferenceImpl.read(this, replyData);
			result.entryCount = readInt("entry count", replyData); //$NON-NLS-1$
			int nrOfWaiters = readInt("nr of waiters", replyData); //$NON-NLS-1$
			result.waiters = new ArrayList(nrOfWaiters);
			for (int i = 0; i < nrOfWaiters; i++)
				result.waiters.add(ThreadReferenceImpl.read(this, replyData));
			return result;
		} catch (IOException e) {
			defaultIOExceptionHandler(e);
			return null;
		} finally {
			handledJdwpRequest();
		}
	}
	
	/** 
	 * @return Returns an ThreadReference for the thread, if any, which currently owns this object's monitor.
	 */
	public ThreadReference owningThread() throws IncompatibleThreadStateException {
		return monitorInfo().owner;
	}

	/** 
	 * @return Returns the number times this object's monitor has been entered by the current owning thread. 
	 */
	public int entryCount() throws IncompatibleThreadStateException {
		return monitorInfo().entryCount;
	}

	/** 
	 * @return Returns a List containing a ThreadReference for each thread currently waiting for this object's monitor.
	 */
	public List waitingThreads() throws IncompatibleThreadStateException {
		return monitorInfo().waiters;
	}
				
	/** 
	 * @return Returns the value of a given instance or static field in this object. 
	 */
	public Value getValue(Field field) {
		ArrayList list = new ArrayList(1);
		list.add(field);
		return (ValueImpl)getValues(list).get(field);
	}
	
	/**
	 * @return Returns objects that directly reference this object. 
	 * Only objects that are reachable for the purposes of garbage collection are returned. 
	 * Note that an object can also be referenced in other ways, such as from a local variable in a stack frame, or from a JNI global reference. Such non-object referrers are not returned by this method.
	 * 
	 * @since 3.3
	 */
	public List referringObjects(long maxReferrers) throws UnsupportedOperationException, IllegalArgumentException {
		try {
			int max = (int)maxReferrers;
			if (maxReferrers >= Integer.MAX_VALUE) {
				max = Integer.MAX_VALUE;
			}
			ByteArrayOutputStream outBytes = new ByteArrayOutputStream();
			DataOutputStream outData = new DataOutputStream(outBytes);
			this.getObjectID().write(outData);
			writeInt(max, "max referrers", outData); //$NON-NLS-1$
						
			JdwpReplyPacket replyPacket = requestVM(JdwpCommandPacket.OR_REFERRING_OBJECTS, outBytes);
			switch(replyPacket.errorCode()) {
				case JdwpReplyPacket.NOT_IMPLEMENTED:
					throw new UnsupportedOperationException(JDIMessages.ReferenceTypeImpl_27);
				case JdwpReplyPacket.ILLEGAL_ARGUMENT:
					throw new IllegalArgumentException(JDIMessages.ReferenceTypeImpl_26);
				case JdwpReplyPacket.INVALID_OBJECT:
					throw new ObjectCollectedException(JDIMessages.ObjectReferenceImpl_object_not_known);
				case JdwpReplyPacket.VM_DEAD:
					throw new VMDisconnectedException(JDIMessages.vm_dead);
			}
			defaultReplyErrorHandler(replyPacket.errorCode());
			
			DataInputStream replyData = replyPacket.dataInStream();
			int elements = readInt("elements", replyData); //$NON-NLS-1$
			if(max > 0 && elements > max) {
				elements = max;
			}
			ArrayList list = new ArrayList();
			for(int i = 0; i < elements; i++) {
				list.add(ValueImpl.readWithTag(this, replyData));
			}
			return list;
		}
		catch(IOException e) {
			defaultIOExceptionHandler(e);
			return null;
		} finally {
			handledJdwpRequest();
		}
	}
	
	/** 
	 * @return Returns the value of multiple instance and/or static fields in this object. 
	 */
	public Map getValues(List allFields) {
		// if the field list is empty, nothing to do.
		if (allFields.isEmpty()) {
			return new HashMap();
		}
		// Note that this information should not be cached.
		initJdwpRequest();
		try {
			ByteArrayOutputStream outBytes = new ByteArrayOutputStream();
			DataOutputStream outData = new DataOutputStream(outBytes);
			
			/*
			 * Distinguish static fields from non-static fields:
			 * For static fields ReferenceTypeImpl.getValues() must be used.
			 */
			List staticFields = new ArrayList();
			List nonStaticFields = new ArrayList();
	
			// Separate static and non-static fields.
			int allFieldsSize = allFields.size();
			for (int i = 0; i < allFieldsSize; i++) {
				FieldImpl field = (FieldImpl)allFields.get(i);
				checkVM(field);
		   		if (field.isStatic())
		   			staticFields.add(field);
		   		else
		   			nonStaticFields.add(field);
			}
			
			// First get values for the static fields.
			Map resultMap;
			if (staticFields.isEmpty()) {
				resultMap= new HashMap();
			} else {
				resultMap= referenceType().getValues(staticFields);
			}
			
			// if no non-static fields are requested, return directly the result.
			if (nonStaticFields.isEmpty()) {
				return resultMap;
			}
			// Then get the values for the non-static fields.
			int nonStaticFieldsSize = nonStaticFields.size();
			write(this, outData);
			writeInt(nonStaticFieldsSize, "size", outData); //$NON-NLS-1$
			for (int i = 0; i < nonStaticFieldsSize; i++) {
				FieldImpl field = (FieldImpl)nonStaticFields.get(i);
				field.write(this, outData);
			}
	
			JdwpReplyPacket replyPacket = requestVM(JdwpCommandPacket.OR_GET_VALUES, outBytes);
			defaultReplyErrorHandler(replyPacket.errorCode());
			
			DataInputStream replyData = replyPacket.dataInStream();
			int nrOfElements = readInt("elements", replyData); //$NON-NLS-1$
			if (nrOfElements != nonStaticFieldsSize) 
				throw new InternalError(JDIMessages.ObjectReferenceImpl_Retrieved_a_different_number_of_values_from_the_VM_than_requested_1); 
				
			for (int i = 0; i < nrOfElements; i++) {
				resultMap.put(nonStaticFields.get(i), ValueImpl.readWithTag(this, replyData));
			}
			return resultMap;
		} catch (IOException e) {
			defaultIOExceptionHandler(e);
			return null;
		} finally {
			handledJdwpRequest();
		}
	}
	
	/** 
	 * @return Returns the hash code value.
	 */
	public int hashCode() {
		return fObjectID.hashCode();
	}
	
	/**
	 * @return Returns true if two mirrors refer to the same entity in the target VM.
	 * @see java.lang.Object#equals(Object)
	 */
	public boolean equals(Object object) {

		return object != null
			&& object.getClass().equals(this.getClass())
			&& fObjectID.equals(((ObjectReferenceImpl)object).fObjectID)
			&& virtualMachine().equals(((MirrorImpl)object).virtualMachine());
	}
	
	/**
	 * @return Returns Jdwp version of given options.
	 */
	private int optionsToJdwpOptions(int options) {
		int jdwpOptions = 0;
   		if ((options & INVOKE_SINGLE_THREADED) != 0) {
   			jdwpOptions |= MethodImpl.INVOKE_SINGLE_THREADED_JDWP;
   		}
   		if ((options & INVOKE_NONVIRTUAL) != 0) {
   			jdwpOptions |= MethodImpl.INVOKE_NONVIRTUAL_JDWP;
   		}
   		return jdwpOptions;
	}
	
	/**
	 * Invokes the specified static Method in the target VM.
	 * @return Returns a Value mirror of the invoked method's return value.
	 */
	public Value invokeMethod(ThreadReference thread, Method method, List arguments, int options) throws InvalidTypeException, ClassNotLoadedException, IncompatibleThreadStateException, InvocationException {
	   	checkVM(thread);
		checkVM(method);
		ThreadReferenceImpl threadImpl = (ThreadReferenceImpl)thread;
		MethodImpl methodImpl = (MethodImpl)method;
		
		// Perform some checks for IllegalArgumentException.
		if (!isAValidMethod(method))
			throw new IllegalArgumentException(JDIMessages.ObjectReferenceImpl_Class_does_not_contain_given_method_2); 
		if (method.argumentTypeNames().size() != arguments.size())
			throw new IllegalArgumentException(JDIMessages.ObjectReferenceImpl_Number_of_arguments_doesn__t_match_3); 
		if (method.isConstructor() || method.isStaticInitializer())
			throw new IllegalArgumentException(JDIMessages.ObjectReferenceImpl_Method_is_constructor_or_intitializer_4); 
		if ((options & INVOKE_NONVIRTUAL) != 0 && method.isAbstract())
			throw new IllegalArgumentException(JDIMessages.ObjectReferenceImpl_Method_is_abstract_and_can_therefore_not_be_invoked_nonvirtual_5); 

		// check the type and the vm of the argument, convert the value if needed.
		List checkedArguments= ValueImpl.checkValues(arguments, method.argumentTypes(), virtualMachineImpl());

		initJdwpRequest();
		try {
			ByteArrayOutputStream outBytes = new ByteArrayOutputStream();
			DataOutputStream outData = new DataOutputStream(outBytes);
			write(this, outData);
			threadImpl.write(this, outData);
			((ReferenceTypeImpl)referenceType()).write(this, outData);
			methodImpl.write(this, outData);
			
			writeInt(checkedArguments.size(), "size", outData); //$NON-NLS-1$
			Iterator iter = checkedArguments.iterator();
			while(iter.hasNext()) {
				ValueImpl elt = (ValueImpl)iter.next();
				if (elt != null) {
					elt.writeWithTag(this, outData);
				} else {
					ValueImpl.writeNullWithTag(this, outData);
				}
			}
			
			writeInt(optionsToJdwpOptions(options),"options", MethodImpl.getInvokeOptions(), outData); //$NON-NLS-1$
			
			JdwpReplyPacket replyPacket = requestVM(JdwpCommandPacket.OR_INVOKE_METHOD, outBytes);
			switch (replyPacket.errorCode()) {
				case JdwpReplyPacket.TYPE_MISMATCH:
					throw new InvalidTypeException();
				case JdwpReplyPacket.INVALID_CLASS:
					throw new ClassNotLoadedException(JDIMessages.ObjectReferenceImpl_One_of_the_arguments_of_ObjectReference_invokeMethod___6); 
				case JdwpReplyPacket.INVALID_THREAD:
					throw new IncompatibleThreadStateException();
				case JdwpReplyPacket.THREAD_NOT_SUSPENDED:
					throw new IncompatibleThreadStateException();
				case JdwpReplyPacket.INVALID_TYPESTATE:
					throw new IncompatibleThreadStateException();
			}
			defaultReplyErrorHandler(replyPacket.errorCode());
			DataInputStream replyData = replyPacket.dataInStream();
			ValueImpl value = ValueImpl.readWithTag(this, replyData);
			ObjectReferenceImpl exception = ObjectReferenceImpl.readObjectRefWithTag(this, replyData);
			if (exception != null)
				throw new InvocationException(exception);
			return value;
		} catch (IOException e) {
			defaultIOExceptionHandler(e);
			return null;
		} finally {
			handledJdwpRequest();
		}
	}

	private boolean isAValidMethod(Method method) {
		ReferenceType refType= referenceType();
		if (refType instanceof ArrayType) {
			// if the object is an array, check if the method is declared in java.lang.Object
			return "java.lang.Object".equals(method.declaringType().name()); //$NON-NLS-1$
		}
		return refType.allMethods().contains(method);
	}
	
	/**
	 * @return Returns if this object has been garbage collected in the target VM.
	 */
	public boolean isCollected() {
		// Note that this information should not be cached.
		initJdwpRequest();
		try {
			JdwpReplyPacket replyPacket = requestVM(JdwpCommandPacket.OR_IS_COLLECTED, this);
			switch (replyPacket.errorCode()) {
				case JdwpReplyPacket.INVALID_OBJECT:
					return true;
				case JdwpReplyPacket.NOT_IMPLEMENTED:
					// Workaround for problem in J2ME WTK (wireless toolkit)
					// @see Bug 12966
					try {
						referenceType();
					} catch (ObjectCollectedException e) {
						return true;
					}
					return false;
				default:
					defaultReplyErrorHandler(replyPacket.errorCode());
					break;
			}
			DataInputStream replyData = replyPacket.dataInStream();
			boolean result = readBoolean("is collected", replyData); //$NON-NLS-1$
			return result;
		} catch (IOException e) {
			defaultIOExceptionHandler(e);
			return false;
		} finally {
			handledJdwpRequest();
		}
	}

	
	/**
	 * @return Returns the ReferenceType that mirrors the type of this object.
	 */
	public ReferenceType referenceType() {
		if (fReferenceType != null) {
			return fReferenceType;
		}
		initJdwpRequest();
		try {
			JdwpReplyPacket replyPacket = requestVM(JdwpCommandPacket.OR_REFERENCE_TYPE, this);
			defaultReplyErrorHandler(replyPacket.errorCode());
			DataInputStream replyData = replyPacket.dataInStream();
			fReferenceType= ReferenceTypeImpl.readWithTypeTag(this, replyData);
			return fReferenceType;
		} catch (IOException e) {
			defaultIOExceptionHandler(e);
			return null;
		} finally {
			handledJdwpRequest();
		}
	}
	
	/**
	 * @return Returns the Type that mirrors the type of this object.
	 */
	public Type type() {
		return referenceType();
	}
	
	/**
	 * Sets the value of a given instance or static field in this object. 
	 */
	public void setValue(Field field, Value value) throws InvalidTypeException, ClassNotLoadedException {
		// Note that this information should not be cached.
		initJdwpRequest();
		try {
			ByteArrayOutputStream outBytes = new ByteArrayOutputStream();
			DataOutputStream outData = new DataOutputStream(outBytes);
			write(this, outData);
			writeInt(1, "size", outData);	// We only set one field //$NON-NLS-1$
			checkVM(field);
			((FieldImpl)field).write(this, outData);

			// check the type and the vm of the value. Convert the value if needed
			ValueImpl checkedValue= ValueImpl.checkValue(value, field.type(), virtualMachineImpl());

			if (checkedValue != null) {
				checkedValue.write(this, outData);
			} else {
				ValueImpl.writeNull(this, outData);
			}
	
			JdwpReplyPacket replyPacket = requestVM(JdwpCommandPacket.OR_SET_VALUES, outBytes);
			switch (replyPacket.errorCode()) {
				case JdwpReplyPacket.TYPE_MISMATCH:
					throw new InvalidTypeException();
				case JdwpReplyPacket.INVALID_CLASS:
					throw new ClassNotLoadedException(referenceType().name());
			}
			defaultReplyErrorHandler(replyPacket.errorCode());
		} catch (IOException e) {
			defaultIOExceptionHandler(e);
		} finally {
			handledJdwpRequest();
		}
	}
	
	/**
	 * @return Returns a unique identifier for this ObjectReference. 
	 */
	public long uniqueID() {
		return fObjectID.value();
	}
		
	/**
	 * @return Returns string with value of ID.
	 */
	public String idString() {
		return "(id=" + fObjectID + ")"; //$NON-NLS-1$ //$NON-NLS-2$
	}

	/**
	 * @return Returns description of Mirror object.
	 */
	public String toString() {
		try {
			return type().toString() + " " + idString(); //$NON-NLS-1$
		} catch (ObjectCollectedException e) {
			return JDIMessages.ObjectReferenceImpl__Garbage_Collected__ObjectReference__8 + idString(); 
		} catch (Exception e) {
			return fDescription;
		}
	}

	/**
	 * @return Reads JDWP representation and returns new instance.
	 */
	public static ObjectReferenceImpl readObjectRefWithoutTag(MirrorImpl target, DataInputStream in) throws IOException {
		VirtualMachineImpl vmImpl = target.virtualMachineImpl();
		JdwpObjectID ID = new JdwpObjectID(vmImpl);
		ID.read(in);
		if (target.fVerboseWriter != null)
			target.fVerboseWriter.println("objectReference", ID.value()); //$NON-NLS-1$

		if (ID.isNull())
			return null;
			
		ObjectReferenceImpl mirror = new ObjectReferenceImpl(vmImpl, ID);
		return mirror;
	}
	
	/**
	 * @return Reads JDWP representation and returns new instance.
	 */
	public static ObjectReferenceImpl readObjectRefWithTag(MirrorImpl target, DataInputStream in) throws IOException {
		byte objectTag = target.readByte("object tag", JdwpID.tagMap(), in); //$NON-NLS-1$
		switch (objectTag) {
	   		case 0:
				return null;
			case ObjectReferenceImpl.tag:
				return ObjectReferenceImpl.readObjectRefWithoutTag(target, in);
			case ArrayReferenceImpl.tag:
				return ArrayReferenceImpl.read(target, in);
			case ClassLoaderReferenceImpl.tag:
				return ClassLoaderReferenceImpl.read(target, in);
			case ClassObjectReferenceImpl.tag:
				return ClassObjectReferenceImpl.read(target, in);
			case StringReferenceImpl.tag:
				return StringReferenceImpl.read(target, in);
			case ThreadGroupReferenceImpl.tag:
				return ThreadGroupReferenceImpl.read(target, in);
			case ThreadReferenceImpl.tag:
				return ThreadReferenceImpl.read(target, in);
   	   	}
		throw new InternalException(JDIMessages.ObjectReferenceImpl_Invalid_ObjectID_tag_encountered___9 + objectTag); 
	}

	/**
	 * Writes JDWP representation without tag.
	 */
	public void write(MirrorImpl target, DataOutputStream out) throws IOException {
		fObjectID.write(out);
		if (target.fVerboseWriter != null)
			target.fVerboseWriter.println("objectReference", fObjectID.value()); //$NON-NLS-1$
	}
}