Copyright (c) 2013, 2016 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
    Chris McGee (IBM) - Bug 380325 - Release filesystem fragment providing Java 7 NIO2 support
    Sergey Prigogin (Google) - ongoing development
/*******************************************************************************
 * Copyright (c) 2013, 2016 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
 *     Chris McGee (IBM) - Bug 380325 - Release filesystem fragment providing Java 7 NIO2 support
 *     Sergey Prigogin (Google) - ongoing development
 *******************************************************************************/
package org.eclipse.core.internal.filesystem.local.nio;

import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.nio.file.*;
import java.nio.file.attribute.DosFileAttributeView;
import java.nio.file.attribute.DosFileAttributes;
import org.eclipse.core.filesystem.EFS;
import org.eclipse.core.filesystem.IFileInfo;
import org.eclipse.core.filesystem.provider.FileInfo;
import org.eclipse.core.internal.filesystem.local.NativeHandler;

NativeHandler for file system that supports legacy "DOS" attributes using
only Java 7 API's. It can be used for DOS/Windows file systems.
/**
 * NativeHandler for file system that supports legacy "DOS" attributes using
 * only Java 7 API's. It can be used for DOS/Windows file systems.
 */
public class DosHandler extends NativeHandler {
	private static final int ATTRIBUTES = EFS.ATTRIBUTE_SYMLINK | EFS.ATTRIBUTE_LINK_TARGET // symbolic link support
			| EFS.ATTRIBUTE_ARCHIVE | EFS.ATTRIBUTE_READ_ONLY | EFS.ATTRIBUTE_HIDDEN; // standard DOS attributes

	@Override
	public FileInfo fetchFileInfo(String fileName) {
		FileInfo info = new FileInfo();

		try {
			Path path = Paths.get(fileName);

			// Use canonical file to get the correct case of filename. See bug 431983.
			Path fileNamePath = path.toRealPath(LinkOption.NOFOLLOW_LINKS).getFileName();
			String canonicalName = fileNamePath == null ? "" : fileNamePath.toString(); //$NON-NLS-1$
			info.setName(canonicalName);

			// To be consistent with the native implementation we do not follow a symbolic link
			// and return back the information about the target. Instead, we provide the information
			// about the symbolic link itself whether it exists or not.
			DosFileAttributes attrs = Files.readAttributes(path, DosFileAttributes.class, LinkOption.NOFOLLOW_LINKS);

			info.setExists(true);
			info.setLastModified(attrs.lastModifiedTime().toMillis());
			info.setLength(attrs.size());
			info.setAttribute(EFS.ATTRIBUTE_ARCHIVE, attrs.isArchive());
			info.setAttribute(EFS.ATTRIBUTE_READ_ONLY, attrs.isReadOnly());
			info.setAttribute(EFS.ATTRIBUTE_HIDDEN, attrs.isHidden());
			if (attrs.isSymbolicLink()) {
				info.setDirectory(isDirectoryLink(attrs));
				info.setAttribute(EFS.ATTRIBUTE_SYMLINK, true);
				info.setStringAttribute(EFS.ATTRIBUTE_LINK_TARGET, Files.readSymbolicLink(path).toString());
			} else {
				info.setDirectory(attrs.isDirectory());
			}
		} catch (NoSuchFileException e) {
			// A non-existing file is not considered an error.
		} catch (IOException e) {
			// Leave alone and continue.
			info.setError(IFileInfo.IO_ERROR);
		}
		return info;
	}

	private boolean isDirectoryLink(DosFileAttributes attrs) {
		// Use reflection to call package protected WindowsFileAttributes.isDirectoryLink() method.
		try {
			Method method = attrs.getClass().getDeclaredMethod("isDirectoryLink"); //$NON-NLS-1$
			method.setAccessible(true);
			return (Boolean) method.invoke(attrs);
		} catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException | NoSuchMethodException | SecurityException e) {
			return false;
		}
	}

	@Override
	public int getSupportedAttributes() {
		return ATTRIBUTES;
	}

	@Override
	public boolean putFileInfo(String fileName, IFileInfo info, int options) {
		Path path = Paths.get(fileName);
		// To be consistent with fetchInfo do not following symbolic links to set archive, read only and hidden attributes.
		DosFileAttributeView view = Files.getFileAttributeView(path, DosFileAttributeView.class, LinkOption.NOFOLLOW_LINKS);
		try {
			view.setArchive(info.getAttribute(EFS.ATTRIBUTE_ARCHIVE));
			view.setReadOnly(info.getAttribute(EFS.ATTRIBUTE_READ_ONLY));
			view.setHidden(info.getAttribute(EFS.ATTRIBUTE_HIDDEN));
		} catch (IOException e) {
			return false;
		}
		return true;
	}
}