/*
* $Id$
*
* Copyright (C) 2003-2015 JNode.org
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; If not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
package org.jnode.fs.ntfs.index;
import java.io.IOException;
import java.util.Iterator;
import java.util.NoSuchElementException;
import org.apache.log4j.Logger;
import org.jnode.fs.ntfs.FileRecord;
import org.jnode.fs.ntfs.attribute.NTFSAttribute;
import org.jnode.util.Queue;
/**
* @author Chira
* @author Ewout Prangsma (epr@users.sourceforge.net)
*/
public final class NTFSIndex {
private final FileRecord fileRecord;
/**
* The name of the index root / allocation attributes to open.
*/
private String attributeName;
private IndexRootAttribute indexRootAttribute;
private IndexAllocationAttribute indexAllocationAttribute;
static final Logger log = Logger.getLogger(NTFSIndex.class);
/**
* Initialize this instance.
*
* @param fileRecord the file record holding the index streams.
* @param attributeName the name of the index root / allocation attributes to open.
*/
public NTFSIndex(FileRecord fileRecord, String attributeName) throws IOException {
this.fileRecord = fileRecord;
this.attributeName = attributeName;
}
/**
* Gets the index root attribute.
*
* @return
*/
public IndexRootAttribute getIndexRootAttribute() {
if (indexRootAttribute == null) {
indexRootAttribute = (IndexRootAttribute)
fileRecord.findAttributesByTypeAndName(NTFSAttribute.Types.INDEX_ROOT, attributeName).next();
log.debug("getIndexRootAttribute: " + indexRootAttribute);
}
return indexRootAttribute;
}
/**
* Gets the index allocation attribute, if any.
*
* @return
*/
public IndexAllocationAttribute getIndexAllocationAttribute() {
if (indexAllocationAttribute == null) {
indexAllocationAttribute = (IndexAllocationAttribute)
fileRecord.findAttributesByTypeAndName(NTFSAttribute.Types.INDEX_ALLOCATION, attributeName).next();
}
return indexAllocationAttribute;
}
/**
* Searches the index for a value.
*
* @param callback the callback to pass each entry in the search to check for a match.
* @return the matching node, or {@code null} if no match is found.
*/
public IndexEntry search(IndexSearchCallback callback) {
Iterator<IndexEntry> rootIterator = getIndexRootAttribute().iterator();
while (rootIterator.hasNext()) {
IndexEntry entry = rootIterator.next();
if (entry.isLastIndexEntryInSubnode()) {
return searchSubTree(entry, callback);
} else {
int compareResult = callback.visitAndCompareEntry(entry);
if (compareResult == 0) {
return entry;
} else if (compareResult < 0) {
return searchSubTree(entry, callback);
} else {
// Maybe in a subsequent node, continue iterating
}
}
}
// No match
return null;
}
/**
* Searches a sub-tree of the index for a value.
*
* @param topEntry the top entry in this sub-tree of the index.
* @param callback the callback to pass each entry in the search to check for a match.
* @return the matching node, or {@code null} if no match is found.
*/
public IndexEntry searchSubTree(IndexEntry topEntry, IndexSearchCallback callback) {
if (!topEntry.hasSubNodes()) {
return null;
}
final IndexBlock indexBlock;
try {
IndexRoot indexRoot = getIndexRootAttribute().getRoot();
indexBlock = getIndexAllocationAttribute().getIndexBlock(indexRoot, topEntry.getSubnodeVCN());
} catch (IOException ex) {
throw new IllegalStateException("Cannot read next index block during search", ex);
}
Iterator<IndexEntry> iterator = indexBlock.iterator();
while (iterator.hasNext()) {
IndexEntry entry = iterator.next();
if (entry.isLastIndexEntryInSubnode()) {
return searchSubTree(entry, callback);
} else {
int compareResult = callback.visitAndCompareEntry(entry);
if (compareResult == 0) {
return entry;
} else if (compareResult < 0) {
return searchSubTree(entry, callback);
} else {
// Maybe in a subsequent node, continue iterating
}
}
}
// No match
return null;
}
public Iterator<IndexEntry> iterator() {
log.debug("iterator");
return new FullIndexEntryIterator();
}
class FullIndexEntryIterator implements Iterator<IndexEntry> {
/**
* List of those IndexEntry's that have a subnode and the subnode has
* not been visited.
*/
private final Queue<IndexEntry> subNodeEntries = new Queue<IndexEntry>();
/** Iterator of current part of the index */
private Iterator<IndexEntry> currentIterator;
private IndexEntry nextEntry;
/**
* Initialize this instance.
*/
public FullIndexEntryIterator() {
log.debug("FullIndexEntryIterator");
currentIterator = getIndexRootAttribute().iterator();
log.debug("currentIterator=" + currentIterator);
readNextEntry();
}
/**
* @see java.util.Iterator#hasNext()
*/
public boolean hasNext() {
return (nextEntry != null);
}
/**
* @see java.util.Iterator#next()
*/
public IndexEntry next() {
final IndexEntry result = nextEntry;
if (result == null) {
throw new NoSuchElementException();
}
readNextEntry();
return result;
}
/**
* @see java.util.Iterator#remove()
*/
public void remove() {
throw new UnsupportedOperationException();
}
private void readNextEntry() {
while (true) {
if (currentIterator.hasNext()) {
// Read it
nextEntry = currentIterator.next();
if (nextEntry.hasSubNodes()) {
log.debug("next has subnode");
subNodeEntries.add(nextEntry);
}
if (!nextEntry.isLastIndexEntryInSubnode()) {
return;
}
}
nextEntry = null;
// Do we have subnodes to iterate over?
if (subNodeEntries.isEmpty()) {
// No, we're done
log.debug("end of list");
return;
}
log.debug("hasNext: read next indexblock");
final IndexEntry entry = subNodeEntries.get();
final IndexRoot indexRoot = getIndexRootAttribute().getRoot();
final IndexBlock indexBlock;
try {
indexBlock = getIndexAllocationAttribute().getIndexBlock(indexRoot, entry.getSubnodeVCN());
} catch (IOException ex) {
throw new RuntimeException("Cannot read next index block", ex);
}
currentIterator = indexBlock.iterator();
}
}
}
}