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
Martin Oberhuber (Wind River) - [184534] get attributes from native lib
/*******************************************************************************
 * 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
 * Martin Oberhuber (Wind River) - [184534] get attributes from native lib
 *******************************************************************************/
package org.eclipse.core.internal.filesystem.local;

import java.net.URL;
import java.util.Enumeration;
import org.eclipse.core.filesystem.IFileInfo;
import org.eclipse.core.filesystem.IFileSystem;
import org.eclipse.core.filesystem.provider.FileInfo;
import org.eclipse.core.internal.filesystem.*;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.osgi.util.NLS;

abstract class LocalFileNatives {
	private static boolean hasNatives = false;
	private static boolean isUnicode = false;
	private static int nativeAttributes = -1;

	
instance of this library /** instance of this library */
	// The name convention is to use the plugin version at the time the library is changed.  
	private static final String LIBRARY_NAME = "localfile_1_0_0"; //$NON-NLS-1$

	static {
		try {
			System.loadLibrary(LIBRARY_NAME);
			hasNatives = true;
			isUnicode = internalIsUnicode();
			try {
				nativeAttributes = nativeAttributes();
			} catch (UnsatisfiedLinkError e) {
				// older native implementations did not support this
				// call, so we need to handle the error silently
			}
		} catch (UnsatisfiedLinkError e) {
			if (isLibraryPresent())
				logMissingNativeLibrary(e);
		}
	}

	private static boolean isLibraryPresent() {
		String libName = System.mapLibraryName(LIBRARY_NAME);
		Enumeration<URL> entries = FileSystemAccess.findEntries("/", libName, true); //$NON-NLS-1$
		return entries != null && entries.hasMoreElements();
	}

	private static void logMissingNativeLibrary(UnsatisfiedLinkError e) {
		String libName = System.mapLibraryName(LIBRARY_NAME);
		String message = NLS.bind(Messages.couldNotLoadLibrary, libName);
		Policy.log(IStatus.INFO, message, e);
	}

	
Return the bit-mask of EFS attributes that this native
file system implementation supports.

This is an optional method: if it has not been compiled
into the native library, the client must catch the 
resulting UnsatisfiedLinkError and handle attributes
as known by older version libraries.

See Also:
attributes.attributes()
Returns:
an integer bit mask of attributes./**
	 * Return the bit-mask of EFS attributes that this native
	 * file system implementation supports.
	 * <p>
	 * This is an optional method: if it has not been compiled
	 * into the native library, the client must catch the 
	 * resulting UnsatisfiedLinkError and handle attributes
	 * as known by older version libraries.
	 * </p>
	 * @see IFileSystem#attributes()
	 * @return an integer bit mask of attributes.
	 */
	private static final native int nativeAttributes();

	
Return the value that the native library thinks IFileSystem.attributes() should return. Returns -1 when the native library has not been loaded, or is a version that does not support this investigation method yet. 
Returns:
an positive value that is a bit-mask suitable for use in IFileSystem.attributes, or -1 if native attributes are not available./**
	 * Return the value that the native library thinks
	 * {@link IFileSystem#attributes()} should return.
	 * 
	 * Returns -1 when the native library has not been
	 * loaded, or is a version that does not support
	 * this investigation method yet.
	 * 
	 * @return an positive value that is a bit-mask
	 *    suitable for use in {@link IFileSystem#attributes},
	 *    or -1 if native attributes are not available. 
	 */
	public static int attributes() {
		return nativeAttributes;
	}

	
Copies file attributes from source to destination. The copyLastModified attribute
indicates whether the lastModified attribute should be copied.
Params:
source – 
destination – 
copyLastModified – 
Returns:
true for success, and false otherwise./**
	 * Copies file attributes from source to destination. The copyLastModified attribute
	 * indicates whether the lastModified attribute should be copied.
	 * @param source 
	 * @param destination 
	 * @param copyLastModified 
	 * @return <code>true</code> for success, and <code>false</code> otherwise.
	 */
	public static boolean copyAttributes(String source, String destination, boolean copyLastModified) {
		if (hasNatives)
			// Note that support for copying last modified info is not implemented on Windows
			return isUnicode ? internalCopyAttributesW(Convert.toPlatformChars(source), Convert.toPlatformChars(destination), copyLastModified) : internalCopyAttributes(Convert.toPlatformBytes(source), Convert.toPlatformBytes(destination), copyLastModified);
		return false; // not supported
	}

	
Params:
fileName – 
Returns:
The file info/**
	 * @param fileName
	 * @return The file info
	 */
	public static FileInfo fetchFileInfo(String fileName) {
		FileInfo info = new FileInfo();
		if (isUnicode)
			internalGetFileInfoW(Convert.toPlatformChars(fileName), info);
		else
			internalGetFileInfo(Convert.toPlatformBytes(fileName), info);
		return info;
	}

	
Copies file attributes from source to destination. The copyLastModified attribute
indicates whether the lastModified attribute should be copied.
/**
	 * Copies file attributes from source to destination. The copyLastModified attribute
	 * indicates whether the lastModified attribute should be copied.
	 */
	private static final native boolean internalCopyAttributes(byte[] source, byte[] destination, boolean copyLastModified);

	
Copies file attributes from source to destination. The copyLastModified attribute
indicates whether the lastModified attribute should be copied (Unicode
version - should not be called if isUnicode is
false).
/**
	 * Copies file attributes from source to destination. The copyLastModified attribute
	 * indicates whether the lastModified attribute should be copied (Unicode
	 * version - should not be called if <code>isUnicode</code> is
	 * <code>false</code>).
	 */
	private static final native boolean internalCopyAttributesW(char[] source, char[] destination, boolean copyLastModified);

	
Stores the file information for the specified filename in the supplied file
information object.  This avoids multiple JNI calls.
/**
	 * Stores the file information for the specified filename in the supplied file
	 * information object.  This avoids multiple JNI calls.
	 */
	private static final native boolean internalGetFileInfo(byte[] fileName, IFileInfo info);

	
Stores the file information for the specified filename in the supplied file
information object.  This avoids multiple JNI calls.
/**
	 * Stores the file information for the specified filename in the supplied file
	 * information object.  This avoids multiple JNI calls.
	 */
	private static final native boolean internalGetFileInfoW(char[] fileName, IFileInfo info);

	
Returns true if the underlying file system API supports Unicode,
false otherwise.
/**
	 * Returns <code>true</code> if the underlying file system API supports Unicode,
	 * <code>false</code> otherwise.
	 */
	private static final native boolean internalIsUnicode();

	
Set the extended attributes specified in the IResource attribute. Only attributes 
that the platform supports will be set. /** Set the extended attributes specified in the IResource attribute. Only attributes 
	 * that the platform supports will be set. */
	private static final native boolean internalSetFileInfo(byte[] fileName, IFileInfo attribute);

	
Set the extended attributes specified in the IResource attribute object. Only 
attributes that the platform supports will be set. (Unicode version - should not 
be called if isUnicode is false). /** Set the extended attributes specified in the IResource attribute object. Only 
	 * attributes that the platform supports will be set. (Unicode version - should not 
	 * be called if <code>isUnicode</code> is <code>false</code>). */
	private static final native boolean internalSetFileInfoW(char[] fileName, IFileInfo attribute, int options);

	
Params:
fileName – 
info – 
options – /**
	 * @param fileName
	 * @param info
	 * @param options
	 */
	public static boolean putFileInfo(String fileName, IFileInfo info, int options) {
		if (isUnicode)
			return internalSetFileInfoW(Convert.toPlatformChars(fileName), info, options);
		return internalSetFileInfo(Convert.toPlatformBytes(fileName), info);
	}

	
Return true if we have found the core library and are using it for
our file-system calls, and false otherwise.
Returns:
true if native library is available, and false
otherwise./**
	 * Return <code>true</code> if we have found the core library and are using it for
	 * our file-system calls, and <code>false</code> otherwise.
	 * @return <code>true</code> if native library is available, and <code>false</code>
	 * otherwise.
	 */
	public static boolean isUsingNatives() {
		return hasNatives;
	}
}