/*******************************************************************************

 * Copyright (c) 2000, 2008 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

 *     Oakland Software Incorporated - added getSessionProperties and getPersistentProperties

 *******************************************************************************/

package org.eclipse.core.internal.resources;

import java.io.*;

import java.util.Map;

import org.eclipse.core.internal.localstore.FileStoreRoot;

import org.eclipse.core.internal.utils.*;

import org.eclipse.core.internal.watson.IElementTreeData;

import org.eclipse.core.resources.IResource;

import org.eclipse.core.runtime.QualifiedName;

/**

 * A data structure containing the in-memory state of a resource in the workspace.

 */

public class ResourceInfo implements IElementTreeData, ICoreConstants, IStringPoolParticipant {

	protected static final int LOWER = 0xFFFF;

	protected static final int UPPER = 0xFFFF0000;

	/** 

	 * This field stores the resource modification stamp in the lower two bytes,

	 * and the character set generation count in the higher two bytes.

	 */

	protected volatile int charsetAndContentId = 0;

	/**

	 * The file system root that this resource is stored in

	 */

	protected FileStoreRoot fileStoreRoot;

	/** Set of flags which reflect various states of the info (used, derived, ...). */

	protected int flags = 0;

	/** Local sync info */

	// thread safety: (Concurrency004)

	protected volatile long localInfo = I_NULL_SYNC_INFO;

	/**

	 * This field stores the sync info generation in the lower two bytes, and

	 * the marker generation count in the upper two bytes.

	 */

	protected volatile int markerAndSyncStamp;

	/** The collection of markers for this resource. */

	protected MarkerSet markers = null;

	/** Modification stamp */

	protected long modStamp = 0;

	/** Unique node identifier */

	// thread safety: (Concurrency004)

	protected volatile long nodeId = 0;

	/** 

	 * The properties which are maintained for the lifecycle of the workspace.

	 * <p>

	 * This field is declared as the implementing class rather than the

	 * interface so we ensure that we get it right since we are making certain

	 * assumptions about the object type w.r.t. casting.

	 */

	protected ObjectMap sessionProperties = null;

	/** 

	 * The table of sync information. 

	 * <p>

	 * This field is declared as the implementing class rather than the

	 * interface so we ensure that we get it right since we are making certain

	 * assumptions about the object type w.r.t. casting.

	 */

	protected ObjectMap syncInfo = null;

	/** 

	 * Returns the integer value stored in the indicated part of this info's flags.

	 */

	protected static int getBits(int flags, int mask, int start) {

		return (flags & mask) >> start;

	}

	/** 

	 * Returns the type setting for this info.  Valid values are 

	 * FILE, FOLDER, PROJECT, 

	 */

	public static int getType(int flags) {

		return getBits(flags, M_TYPE, M_TYPE_START);

	}

	/** 

	 * Returns true if all of the bits indicated by the mask are set.

	 */

	public static boolean isSet(int flags, int mask) {

		return (flags & mask) == mask;

	}

	/** 

	 * Clears all of the bits indicated by the mask.

	 */

	public void clear(int mask) {

		flags &= ~mask;

	}

	public void clearModificationStamp() {

		modStamp = IResource.NULL_STAMP;

	}

	public synchronized void clearSessionProperties() {

		sessionProperties = null;

	}

	public Object clone() {

		try {

			return super.clone();

		} catch (CloneNotSupportedException e) {

			return null; // never gets here.

		}

	}

	public int getCharsetGenerationCount() {

		return charsetAndContentId >> 16;

	}

	public int getContentId() {

		return charsetAndContentId & LOWER;

	}

	public FileStoreRoot getFileStoreRoot() {

		return fileStoreRoot;

	}

	/** 

	 * Returns the set of flags for this info.

	 */

	public int getFlags() {

		return flags;

	}

	/** 

	 * Gets the local-relative sync information.

	 */

	public long getLocalSyncInfo() {

		return localInfo;

	}

	/** 

	 * Returns the marker generation count.

	 * The count is incremented whenever markers on the resource change.

	 */

	public int getMarkerGenerationCount() {

		return markerAndSyncStamp >> 16;

	}

	/** 

	 * Returns a copy of the collection of makers on this resource.

	 * <code>null</code> is returned if there are none.

	 */

	public MarkerSet getMarkers() {

		return getMarkers(true);

	}

	/** 

	 * Returns the collection of makers on this resource.

	 * <code>null</code> is returned if there are none.

	 */

	public MarkerSet getMarkers(boolean makeCopy) {

		if (markers == null)

			return null;

		return makeCopy ? (MarkerSet) markers.clone() : markers;

	}

	public long getModificationStamp() {

		return modStamp;

	}

	public long getNodeId() {

		return nodeId;

	}

	/**

	 * Returns the property store associated with this info.  The return value may be null.

	 */

	public Object getPropertyStore() {

		return null;

	}

	/** 

	 * Returns a copy of the map of this resource session properties.

	 * An empty map is returned if there are none.

	 */

	public Map getSessionProperties() {

		// thread safety: (Concurrency001)

		ObjectMap temp = sessionProperties;

		if (temp == null)

			temp = new ObjectMap(5);

		else

			temp = (ObjectMap) sessionProperties.clone();

		return temp;

	}

	/** 

	 * Returns the value of the identified session property

	 */

	public Object getSessionProperty(QualifiedName name) {

		// thread safety: (Concurrency001)

		Map temp = sessionProperties;

		if (temp == null)

			return null;

		return temp.get(name);

	}

	/**

	 * The parameter to this method is the implementing class rather than the

	 * interface so we ensure that we get it right since we are making certain

	 * assumptions about the object type w.r.t. casting.

	 */

	public synchronized ObjectMap getSyncInfo(boolean makeCopy) {

		if (syncInfo == null)

			return null;

		return makeCopy ? (ObjectMap) syncInfo.clone() : syncInfo;

	}

	public synchronized byte[] getSyncInfo(QualifiedName id, boolean makeCopy) {

		// thread safety: (Concurrency001)

		byte[] b;

		if (syncInfo == null)

			return null;

		b = (byte[]) syncInfo.get(id);

		return b == null ? null : (makeCopy ? (byte[]) b.clone() : b);

	}

	/** 

	 * Returns the sync information generation count.

	 * The count is incremented whenever sync info on the resource changes.

	 */

	public int getSyncInfoGenerationCount() {

		return markerAndSyncStamp & LOWER;

	}

	/** 

	 * Returns the type setting for this info.  Valid values are 

	 * FILE, FOLDER, PROJECT, 

	 */

	public int getType() {

		return getType(flags);

	}

	/** 

	 * Increments the charset generation count.

	 * The count is incremented whenever the encoding on the resource changes.

	 */

	public void incrementCharsetGenerationCount() {

		//increment high order bits

		charsetAndContentId = ((charsetAndContentId + LOWER + 1) & UPPER) + (charsetAndContentId & LOWER);

	}

	/** 

	 * Mark this resource info as having changed content

	 */

	public void incrementContentId() {

		//increment low order bits

		charsetAndContentId = (charsetAndContentId & UPPER) + ((charsetAndContentId + 1) & LOWER);

	}

	/** 

	 * Increments the marker generation count.

	 * The count is incremented whenever markers on the resource change.

	 */

	public void incrementMarkerGenerationCount() {

		//increment high order bits

		markerAndSyncStamp = ((markerAndSyncStamp + LOWER + 1) & UPPER) + (markerAndSyncStamp & LOWER);

	}

	/** 

	 * Change the modification stamp to indicate that this resource has changed.

	 * The exact value of the stamp doesn't matter, as long as it can be used to

	 * distinguish two arbitrary resource generations.

	 */

	public void incrementModificationStamp() {

		modStamp++;

	}

	/** 

	 * Increments the sync information generation count.

	 * The count is incremented whenever sync info on the resource changes.

	 */

	public void incrementSyncInfoGenerationCount() {

		//increment low order bits

		markerAndSyncStamp = (markerAndSyncStamp & UPPER) + ((markerAndSyncStamp + 1) & LOWER);

	}

	/** 

	 * Returns true if all of the bits indicated by the mask are set.

	 */

	public boolean isSet(int mask) {

		return (flags & mask) == mask;

	}

	public void readFrom(int newFlags, DataInput input) throws IOException {

		// The flags for this info are read by the visitor (flattener). 

		// See Workspace.readElement().  This allows the reader to look ahead 

		// and see what type of info is being loaded.

		this.flags = newFlags;

		localInfo = input.readLong();

		nodeId = input.readLong();

		charsetAndContentId = input.readInt() & LOWER;

		modStamp = input.readLong();

	}

	/** 

	 * Sets all of the bits indicated by the mask.

	 */

	public void set(int mask) {

		flags |= mask;

	}

	/** 

	 * Sets the value of the indicated bits to be the given value.

	 */

	protected void setBits(int mask, int start, int value) {

		int baseMask = mask >> start;

		int newValue = (value & baseMask) << start;

		// thread safety: (guarantee atomic assignment)

		int temp = flags;

		temp &= ~mask;

		temp |= newValue;

		flags = temp;

	}

	public void setFileStoreRoot(FileStoreRoot fileStoreRoot) {

		this.fileStoreRoot = fileStoreRoot;

	}

	/** 

	 * Sets the flags for this info.

	 */

	protected void setFlags(int value) {

		flags = value;

	}

	/** 

	 * Sets the local-relative sync information.

	 */

	public void setLocalSyncInfo(long info) {

		localInfo = info;

	}

	/** 

	 * Sets the collection of makers for this resource.

	 * <code>null</code> is passed in if there are no markers.

	 */

	public void setMarkers(MarkerSet value) {

		markers = value;

	}

	/**

	 * Sets the resource modification stamp.

	 */

	public void setModificationStamp(long value) {

		this.modStamp = value;

	}

	/** 

	 *

	 */

	public void setNodeId(long id) {

		nodeId = id;

	}

	/**

	 * Sets the property store associated with this info.  The value may be null.

	 */

	public void setPropertyStore(Object value) {

		// needs to be implemented on subclasses

	}

	/** 

	 * Sets the identified session property to the given value.  If

	 * the value is null, the property is removed.

	 */

	public synchronized void setSessionProperty(QualifiedName name, Object value) {

		// thread safety: (Concurrency001)

		if (value == null) {

			if (sessionProperties == null)

				return;

			ObjectMap temp = (ObjectMap) sessionProperties.clone();

			temp.remove(name);

			if (temp.isEmpty())

				sessionProperties = null;

			else

				sessionProperties = temp;

		} else {

			ObjectMap temp = sessionProperties;

			if (temp == null)

				temp = new ObjectMap(5);

			else

				temp = (ObjectMap) sessionProperties.clone();

			temp.put(name, value);

			sessionProperties = temp;

		}

	}

	/**

	 * The parameter to this method is the implementing class rather than the

	 * interface so we ensure that we get it right since we are making certain

	 * assumptions about the object type w.r.t. casting.

	 */

	protected void setSyncInfo(ObjectMap syncInfo) {

		this.syncInfo = syncInfo;

	}

	public synchronized void setSyncInfo(QualifiedName id, byte[] value) {

		if (value == null) {

			//delete sync info

			if (syncInfo == null)

				return;

			syncInfo.remove(id);

			if (syncInfo.isEmpty())

				syncInfo = null;

		} else {

			//add sync info

			if (syncInfo == null)

				syncInfo = new ObjectMap(5);

			syncInfo.put(id, value.clone());

		}

	}

	/** 

	 * Sets the type for this info to the given value.  Valid values are 

	 * FILE, FOLDER, PROJECT

	 */

	public void setType(int value) {

		setBits(M_TYPE, M_TYPE_START, value);

	}

	/* (non-Javadoc

	 * Method declared on IStringPoolParticipant

	 */

	public void shareStrings(StringPool set) {

		ObjectMap map = syncInfo;

		if (map != null)

			map.shareStrings(set);

		map = sessionProperties;

		if (map != null)

			map.shareStrings(set);

		MarkerSet markerSet = markers;

		if (markerSet != null)

			markerSet.shareStrings(set);

	}

	public void writeTo(DataOutput output) throws IOException {

		// The flags for this info are written by the visitor (flattener). 

		// See SaveManager.writeElement().  This allows the reader to look ahead 

		// and see what type of info is being loaded.

		output.writeLong(localInfo);

		output.writeLong(nodeId);

		output.writeInt(getContentId());

		output.writeLong(modStamp);

	}

}