ZipFileStructureProvider.java

/*******************************************************************************
 * Copyright (c) 2005 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.buckminster.pde.internal.datatransfer;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Path;

/**
 * This class provides information regarding the context structure and content
 * of specified zip file entry objects.
 */
@SuppressWarnings({ "rawtypes", "unchecked" })
public class ZipFileStructureProvider implements IImportStructureProvider {
	private ZipFile zipFile;

	private ZipEntry root = new ZipEntry("/");//$NON-NLS-1$

	private Map children;

	private Map directoryEntryCache = new HashMap();

	/**
	 * Creates a <code>ZipFileStructureProvider</code>, which will operate on
	 * the passed zip file.
	 */
	public ZipFileStructureProvider(ZipFile sourceFile) {
		super();
		zipFile = sourceFile;
	}

	/*
	 * (non-Javadoc) Method declared on IImportStructureProvider
	 */
	@Override
	public List getChildren(Object element) {
		if (children == null)
			initialize();

		return ((List) children.get(element));
	}

	/*
	 * (non-Javadoc) Method declared on IImportStructureProvider
	 */
	@Override
	public InputStream getContents(Object element) {
		try {
			return zipFile.getInputStream((ZipEntry) element);
		} catch (IOException e) {
			return null;
		}
	}

	/*
	 * (non-Javadoc) Method declared on IImportStructureProvider
	 */
	@Override
	public String getFullPath(Object element) {
		return ((ZipEntry) element).getName();
	}

	/*
	 * (non-Javadoc) Method declared on IImportStructureProvider
	 */
	@Override
	public String getLabel(Object element) {
		if (element.equals(root))
			return ((ZipEntry) element).getName();

		return new Path(((ZipEntry) element).getName()).lastSegment();
	}

	/**
	 * Returns the entry that this importer uses as the root sentinel.
	 * 
	 * @return java.util.zip.ZipEntry
	 */
	public ZipEntry getRoot() {
		return root;
	}

	/**
	 * Returns the zip file that this provider provides structure for.
	 */
	public ZipFile getZipFile() {
		return zipFile;
	}

	/*
	 * (non-Javadoc) Method declared on IImportStructureProvider
	 */
	@Override
	public boolean isFolder(Object element) {
		return ((ZipEntry) element).isDirectory();
	}

	/**
	 * Adds the specified child to the internal collection of the parent's
	 * children.
	 */
	protected void addToChildren(ZipEntry parent, ZipEntry child) {
		List childList = (List) children.get(parent);
		if (childList == null) {
			childList = new ArrayList();
			children.put(parent, childList);
		}

		childList.add(child);
	}

	/**
	 * Creates a new container zip entry with the specified name, iff it has not
	 * already been created.
	 */
	protected void createContainer(IPath pathname) {
		if (directoryEntryCache.containsKey(pathname))
			return;

		ZipEntry parent;
		if (pathname.segmentCount() == 1)
			parent = root;
		else
			parent = (ZipEntry) directoryEntryCache.get(pathname.removeLastSegments(1));

		ZipEntry newEntry = new ZipEntry(pathname.toString());
		directoryEntryCache.put(pathname, newEntry);
		addToChildren(parent, newEntry);
	}

	/**
	 * Creates a new file zip entry with the specified name.
	 */
	protected void createFile(ZipEntry entry) {
		IPath pathname = new Path(entry.getName());
		ZipEntry parent;
		if (pathname.segmentCount() == 1)
			parent = root;
		else
			parent = (ZipEntry) directoryEntryCache.get(pathname.removeLastSegments(1));

		addToChildren(parent, entry);
	}

	/**
	 * Initializes this object's children table based on the contents of the
	 * specified source file.
	 */
	protected void initialize() {
		children = new HashMap(1000);

		Enumeration entries = zipFile.entries();
		while (entries.hasMoreElements()) {
			ZipEntry entry = (ZipEntry) entries.nextElement();
			if (!entry.isDirectory()) {
				IPath path = new Path(entry.getName()).addTrailingSeparator();
				int pathSegmentCount = path.segmentCount();

				for (int i = 1; i < pathSegmentCount; i++)
					createContainer(path.uptoSegment(i));
				createFile(entry);
			}
		}
	}
}