Copyright (c) 2000, 2018 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
/*******************************************************************************
 * Copyright (c) 2000, 2018 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
 *******************************************************************************/
package org.eclipse.debug.core.sourcelookup.containers;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.debug.core.DebugPlugin;
import org.eclipse.debug.core.sourcelookup.ISourceContainerType;
import org.eclipse.debug.internal.core.sourcelookup.SourceLookupMessages;
import org.eclipse.debug.internal.core.sourcelookup.SourceLookupUtils;

import com.ibm.icu.text.MessageFormat;

An archive in the local file system. Returns instances
of ZipEntryStorage as source elements.

Clients may instantiate this class.

Since:
3.0
@noextend
This class is not intended to be subclassed by clients./**
 * An archive in the local file system. Returns instances
 * of <code>ZipEntryStorage</code> as source elements.
 * <p>
 * Clients may instantiate this class.
 * </p>
 * @since 3.0
 * @noextend This class is not intended to be subclassed by clients.
 */
public class ExternalArchiveSourceContainer extends AbstractSourceContainer {

	private boolean fDisposed;
	private boolean fDetectRoots;
	private Set<String> fPotentialRoots;
	private List<String> fRoots = new ArrayList<>();
	private String fArchivePath;
	
Unique identifier for the external archive source container type
(value org.eclipse.debug.core.containerType.externalArchive).
/**
	 * Unique identifier for the external archive source container type
	 * (value <code>org.eclipse.debug.core.containerType.externalArchive</code>).
	 */
	public static final String TYPE_ID = DebugPlugin.getUniqueIdentifier() + ".containerType.externalArchive";	 //$NON-NLS-1$

	
Creates an archive source container on the archive at the
specified location in the local file system.
Params:
archivePath – path to the archive in the local file system
detectRootPaths – whether root container paths should be detected. When
  true, searching is performed relative to a root path
  within the archive based on fully qualified file names. A root
  path is automatically determined for when the first
  successful search is performed. For example, when searching for a file
  named a/b/c.d, and an entry in the archive named
  r/a/b/c.d exists, a root path is set to r.
  When searching for an unqualified file name, root containers are not
  considered.
  When false, searching is performed by
  matching file names as suffixes to the entries in the archive./**
	 * Creates an archive source container on the archive at the
	 * specified location in the local file system.
	 *
	 * @param archivePath path to the archive in the local file system
	 * @param detectRootPaths whether root container paths should be detected. When
	 *   <code>true</code>, searching is performed relative to a root path
	 *   within the archive based on fully qualified file names. A root
	 *   path is automatically determined for when the first
	 *   successful search is performed. For example, when searching for a file
	 *   named <code>a/b/c.d</code>, and an entry in the archive named
	 *   <code>r/a/b/c.d</code> exists, a root path is set to <code>r</code>.
	 *   When searching for an unqualified file name, root containers are not
	 *   considered.
	 *   When <code>false</code>, searching is performed by
	 *   matching file names as suffixes to the entries in the archive.
	 */
	public ExternalArchiveSourceContainer(String archivePath, boolean detectRootPaths) {
		fArchivePath = archivePath;
		fDetectRoots = detectRootPaths;
	}

	@SuppressWarnings("resource")
	@Override
	public Object[] findSourceElements(String name) throws CoreException {
		String newname = name.replace('\\', '/');
		ZipFile file = getArchive();
		if (file == null) {
			return EMPTY;
		}
		// NOTE: archive can be closed between get (above) and synchronized block (below)
		synchronized (file) {
			boolean isQualfied = newname.indexOf('/') > 0;
			if (fDetectRoots && isQualfied) {
				ZipEntry entry = searchRoots(file, newname);
				if (entry != null) {
					return new Object[]{new ZipEntryStorage(file, entry)};
				}
			} else {
				// try exact match
				ZipEntry entry = null;
				try {
					entry = file.getEntry(newname);
				} catch (IllegalStateException e) {
					// archive was closed between retrieving and locking
					throw new CoreException(new Status(IStatus.ERROR, DebugPlugin.getUniqueIdentifier(),
							e.getMessage(), e));
				}
				if (entry != null) {
					// can't be any duplicates if there is an exact match
					return new Object[]{new ZipEntryStorage(file, entry)};
				}
				// search
				Enumeration<? extends ZipEntry> entries = file.entries();
				List<ZipEntryStorage> matches = null;
				try {
					File zipFile = new File(fArchivePath);
					String zipFileCanonical = zipFile.getCanonicalPath();
					while (entries.hasMoreElements()) {
						entry = entries.nextElement();
						String entryName = entry.getName();
						if (entryName.endsWith(newname)) {
							String zipEntryCanonical = (new File(zipFile, entryName)).getCanonicalPath();
							if (!zipEntryCanonical.startsWith(zipFileCanonical + File.separator)) {
								throw new CoreException(new Status(IStatus.ERROR, DebugPlugin.getUniqueIdentifier(), "Invalid path: " + zipEntryCanonical)); //$NON-NLS-1$
							}
							if (isQualfied || entryName.length() == newname.length() || entryName.charAt(entryName.length() - newname.length() - 1) == '/') {
								if (isFindDuplicates()) {
									if (matches == null) {
										matches = new ArrayList<>();
									}
									matches.add(new ZipEntryStorage(file, entry));
								} else {
									return new Object[] {
											new ZipEntryStorage(file, entry) };
								}
							}
						}
					}
				} catch (IOException e) {
					throw new CoreException(new Status(IStatus.ERROR, DebugPlugin.getUniqueIdentifier(), "Invalid path: " + fArchivePath)); //$NON-NLS-1$
				}
				if (matches != null) {
					return matches.toArray();
				}
			}
		}
		return EMPTY;
	}

	
Returns the root path in this archive for the given file name, based
on its type, or null if none. Detects a root if a root has
not yet been detected for the given file type.
Params:
file – zip file to search in
name – file name
Throws:
CoreException – if an exception occurs while detecting the root
Returns:
the ZipEntry with the given name or null/**
	 * Returns the root path in this archive for the given file name, based
	 * on its type, or <code>null</code> if none. Detects a root if a root has
	 * not yet been detected for the given file type.
	 *
	 * @param file zip file to search in
	 * @param name file name
	 * @return the {@link ZipEntry} with the given name or <code>null</code>
	 * @exception CoreException if an exception occurs while detecting the root
	 */
	private synchronized ZipEntry searchRoots(ZipFile file, String name) throws CoreException {
		if (fDisposed) {
			return null;
		}
		if (fPotentialRoots == null) {
			fPotentialRoots = new HashSet<>();
			fPotentialRoots.add(""); //$NON-NLS-1$
			// all potential roots are the directories
			try {
				Enumeration<? extends ZipEntry> entries = file.entries();
				while (entries.hasMoreElements()) {
					ZipEntry entry = entries.nextElement();
					if (entry.isDirectory()) {
						fPotentialRoots.add(entry.getName());
					} else {
						String entryName = entry.getName();
						int index = entryName.lastIndexOf('/'); 
						while (index > 0) {
							if (fPotentialRoots.add(entryName.substring(0, index + 1))) {
								entryName = entryName.substring(0, index);
								index = entryName.lastIndexOf('/'); 
							} else {
								break;
							}
						}
					}
				}
			} catch (IllegalStateException e) {
				// archive was closed between retrieving and locking
				throw new CoreException(new Status(IStatus.ERROR, DebugPlugin.getUniqueIdentifier(),
					e.getMessage(), e));
			}
		}
		int i = 0;
		while (i < fRoots.size()) {
			String root = fRoots.get(i);
			ZipEntry entry = file.getEntry(root+name);
			if (entry != null) {
				return entry;
			}
			i++;
		}
		if (!fPotentialRoots.isEmpty()) {
			for (String root : fPotentialRoots) {
				ZipEntry entry = file.getEntry(root + name);
				if (entry != null) {
					if (root != null) {
						fRoots.add(root);
						fPotentialRoots.remove(root);
						// remove any roots that begin with the new root, as
						// roots
						// cannot be nested
						Iterator<String> rs = fPotentialRoots.iterator();
						while (rs.hasNext()) {
							String r = rs.next();
							if (r.startsWith(root)) {
								rs.remove();
							}
						}
					}
					return entry;
				}
			}
		}
		return null;
	}

	
Returns the archive to search in.
Throws:
CoreException – if unable to access the archive
Returns:
the ZipFile to search in/**
	 * Returns the archive to search in.
	 * @return the {@link ZipFile} to search in
	 *
	 * @throws CoreException if unable to access the archive
	 */
	private synchronized ZipFile getArchive() throws CoreException {
		if (fDisposed) {
			return null;
		}
		try {
			return SourceLookupUtils.getZipFile(fArchivePath);
		} catch (IOException e) {
			File file = new File(fArchivePath);
			if (file.exists()) {
				abort(MessageFormat.format(SourceLookupMessages.ExternalArchiveSourceContainer_2, new Object[] { fArchivePath }), e);
			} else {
				warn(MessageFormat.format(SourceLookupMessages.ExternalArchiveSourceContainer_1, new Object[] { fArchivePath }), e);
			}
		}
		return null;
	}

	@Override
	public String getName() {
		return fArchivePath;
	}

	@Override
	public ISourceContainerType getType() {
		return getSourceContainerType(TYPE_ID);
	}

	
Returns whether root paths are automatically detected in this
archive source container.
Returns:
whether root paths are automatically detected in this
archive source container/**
	 * Returns whether root paths are automatically detected in this
	 * archive source container.
	 *
	 * @return whether root paths are automatically detected in this
	 * archive source container
	 */
	public boolean isDetectRoot() {
		return fDetectRoots;
	}

	@Override
	public boolean equals(Object obj) {
		return obj instanceof ExternalArchiveSourceContainer &&
			((ExternalArchiveSourceContainer)obj).getName().equals(getName());
	}

	@Override
	public int hashCode() {
		return getName().hashCode();
	}

	@Override
	public synchronized void dispose() {
		super.dispose();
		if (fPotentialRoots != null) {
			fPotentialRoots.clear();
		}
		fRoots.clear();
		fDisposed = true;
	}
}