Copyright (c) 2000, 2015 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
    alex.panchenko@gmail.com - Bug 470535 - Bug in UserLibrary.hashCode()
/*******************************************************************************
 * Copyright (c) 2000, 2015 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     alex.panchenko@gmail.com - Bug 470535 - Bug in UserLibrary.hashCode()
 *******************************************************************************/
package org.eclipse.jdt.internal.core;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.util.ArrayList;
import java.util.HashMap;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Path;
import org.eclipse.jdt.core.IAccessRule;
import org.eclipse.jdt.core.IClasspathAttribute;
import org.eclipse.jdt.core.IClasspathEntry;
import org.eclipse.jdt.core.JavaCore;
import org.eclipse.jdt.internal.core.util.Messages;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

Internal model element to represent a user library and code to serialize / deserialize.
/**
 * Internal model element to represent a user library and code to serialize / deserialize.
 */
@SuppressWarnings({"rawtypes", "unchecked"})
public class UserLibrary {

	private static final String VERSION_ONE = "1"; //$NON-NLS-1$
	private static final String CURRENT_VERSION= "2"; //$NON-NLS-1$

	private static final String TAG_VERSION= "version"; //$NON-NLS-1$
	private static final String TAG_USERLIBRARY= "userlibrary"; //$NON-NLS-1$
	private static final String TAG_SOURCEATTACHMENT= "sourceattachment"; //$NON-NLS-1$
	private static final String TAG_SOURCEATTACHMENTROOT= "sourceattachmentroot"; //$NON-NLS-1$
	private static final String TAG_PATH= "path"; //$NON-NLS-1$
	private static final String TAG_ARCHIVE= "archive"; //$NON-NLS-1$
	private static final String TAG_SYSTEMLIBRARY= "systemlibrary"; //$NON-NLS-1$

	private boolean isSystemLibrary;
	private IClasspathEntry[] entries;

	public UserLibrary(IClasspathEntry[] entries, boolean isSystemLibrary) {
		Assert.isNotNull(entries);
		this.entries= entries;
		this.isSystemLibrary= isSystemLibrary;
	}

	public IClasspathEntry[] getEntries() {
		return this.entries;
	}

	public boolean isSystemLibrary() {
		return this.isSystemLibrary;
	}

	@Override
	public boolean equals(Object obj) {
		if (obj != null && obj.getClass() == getClass()) {
			UserLibrary other= (UserLibrary) obj;
			if (this.entries.length == other.entries.length && this.isSystemLibrary == other.isSystemLibrary) {
				for (int i= 0; i < this.entries.length; i++) {
					if (!this.entries[i].equals(other.entries[i])) {
						return false;
					}
				}
				return true;
			}
		}
		return false;
	}

	@Override
	public int hashCode() {
		int hashCode= 0;
		if (this.isSystemLibrary) {
			hashCode++;
		}
		for (int i= 0; i < this.entries.length; i++) {
			hashCode= hashCode * 17 + this.entries[i].hashCode();
		}
		return hashCode;
	}

	public static String serialize(IClasspathEntry[] entries, boolean isSystemLibrary) throws IOException {
		ByteArrayOutputStream s = new ByteArrayOutputStream();
		OutputStreamWriter writer = new OutputStreamWriter(s, "UTF8"); //$NON-NLS-1$
		XMLWriter xmlWriter = new XMLWriter(writer, null/*use the workspace line delimiter*/, true/*print XML version*/);

		HashMap library = new HashMap();
		library.put(TAG_VERSION, String.valueOf(CURRENT_VERSION));
		library.put(TAG_SYSTEMLIBRARY, String.valueOf(isSystemLibrary));
		xmlWriter.printTag(TAG_USERLIBRARY, library, true, true, false);

		for (int i = 0, length = entries.length; i < length; ++i) {
			ClasspathEntry cpEntry = (ClasspathEntry) entries[i];

			HashMap archive = new HashMap();
			archive.put(TAG_PATH, cpEntry.getPath().toPortableString());
			IPath sourceAttach= cpEntry.getSourceAttachmentPath();
			if (sourceAttach != null)
				archive.put(TAG_SOURCEATTACHMENT, sourceAttach.toPortableString());
			IPath sourceAttachRoot= cpEntry.getSourceAttachmentRootPath();
			if (sourceAttachRoot != null)
				archive.put(TAG_SOURCEATTACHMENTROOT, sourceAttachRoot.toPortableString());

			boolean hasExtraAttributes = cpEntry.extraAttributes != null && cpEntry.extraAttributes.length != 0;
			boolean hasRestrictions = cpEntry.getAccessRuleSet() != null; // access rule set is null if no access rules
			xmlWriter.printTag(TAG_ARCHIVE, archive, true, true, !(hasExtraAttributes || hasRestrictions));

			// write extra attributes if necessary
			if (hasExtraAttributes) {
				cpEntry.encodeExtraAttributes(xmlWriter, true, true);
			}

			// write extra attributes and restriction if necessary
			if (hasRestrictions) {
				cpEntry.encodeAccessRules(xmlWriter, true, true);
			}

			// write archive end tag if necessary
			if (hasExtraAttributes || hasRestrictions) {
				xmlWriter.endTag(TAG_ARCHIVE, true/*insert tab*/, true/*insert new line*/);
			}
		}
		xmlWriter.endTag(TAG_USERLIBRARY, true/*insert tab*/, true/*insert new line*/);
		writer.flush();
		writer.close();
		return s.toString("UTF8");//$NON-NLS-1$
	}

	public static UserLibrary createFromString(Reader reader) throws IOException {
		Element cpElement;
		try {
			DocumentBuilder parser = DocumentBuilderFactory.newInstance().newDocumentBuilder();
			cpElement = parser.parse(new InputSource(reader)).getDocumentElement();
		} catch (SAXException | ParserConfigurationException e) {
			throw new IOException(Messages.file_badFormat, e);
		} finally {
			reader.close();
		}

		if (!cpElement.getNodeName().equalsIgnoreCase(TAG_USERLIBRARY)) {
			throw new IOException(Messages.file_badFormat);
		}
		String version= cpElement.getAttribute(TAG_VERSION);
		boolean isSystem= Boolean.valueOf(cpElement.getAttribute(TAG_SYSTEMLIBRARY)).booleanValue();

		NodeList list= cpElement.getChildNodes();
		int length = list.getLength();

		ArrayList res= new ArrayList(length);
		for (int i = 0; i < length; ++i) {
			Node node = list.item(i);

			if (node.getNodeType() == Node.ELEMENT_NODE) {
				Element element= (Element) node;
				if (element.getNodeName().equals(TAG_ARCHIVE)) {
					String pathString = element.getAttribute(TAG_PATH);
					String sourceAttachString = element.hasAttribute(TAG_SOURCEATTACHMENT) ? element.getAttribute(TAG_SOURCEATTACHMENT) : null;
					String sourceAttachRootString = element.hasAttribute(TAG_SOURCEATTACHMENTROOT) ? element.getAttribute(TAG_SOURCEATTACHMENTROOT) : null;
					IPath entryPath = null; 
					IPath sourceAttachPath = null;
					IPath sourceAttachRootPath = null;
					if (version.equals(VERSION_ONE)) {
						entryPath = Path.fromOSString(pathString);
						if (sourceAttachString != null) sourceAttachPath = Path.fromOSString(sourceAttachString);
						if (sourceAttachRootString != null) sourceAttachRootPath = Path.fromOSString(sourceAttachRootString);
					}
					else {
						entryPath = Path.fromPortableString(pathString);
						if (sourceAttachString != null) sourceAttachPath = Path.fromPortableString(sourceAttachString);
						if (sourceAttachRootString != null) sourceAttachRootPath = Path.fromPortableString(sourceAttachRootString);
					}

					NodeList children = element.getElementsByTagName("*"); //$NON-NLS-1$
					boolean[] foundChildren = new boolean[children.getLength()];
					NodeList attributeList = ClasspathEntry.getChildAttributes(ClasspathEntry.TAG_ATTRIBUTES, children, foundChildren);
					IClasspathAttribute[] extraAttributes = ClasspathEntry.decodeExtraAttributes(attributeList);
					attributeList = ClasspathEntry.getChildAttributes(ClasspathEntry.TAG_ACCESS_RULES, children, foundChildren);
					IAccessRule[] accessRules = ClasspathEntry.decodeAccessRules(attributeList);
					IClasspathEntry entry = JavaCore.newLibraryEntry(entryPath, sourceAttachPath, sourceAttachRootPath, accessRules, extraAttributes, false/*not exported*/);
					res.add(entry);
				}
			}
		}

		IClasspathEntry[] entries= (IClasspathEntry[]) res.toArray(new IClasspathEntry[res.size()]);

		return new UserLibrary(entries, isSystem);
	}

	@Override
	public String toString() {
		if (this.entries == null)
			return "null"; //$NON-NLS-1$
		StringBuffer buffer = new StringBuffer();
		int length = this.entries.length;
		for (int i=0; i<length; i++) {
			buffer.append(this.entries[i].toString()+'\n');
		}
		return buffer.toString();
	}
}