--- /dev/null
+package org.apache.lucene.index;
+
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.io.EOFException;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.util.HashMap;
+
+import org.apache.lucene.store.BufferedIndexInput;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.IndexOutput;
+import org.apache.lucene.store.Lock;
+
+/**
+ * Class for accessing a compound stream.
+ * This class implements a directory, but is limited to only read operations.
+ * Directory methods that would normally modify data throw an exception.
+ */
+class CompoundFileReader extends Directory {
+
+ private int readBufferSize;
+
+ private static final class FileEntry {
+ long offset;
+ long length;
+ }
+
+ // Base info
+ private Directory directory;
+ private String fileName;
+
+ private IndexInput stream;
+ private HashMap<String,FileEntry> entries = new HashMap<String,FileEntry>();
+
+ public CompoundFileReader(Directory dir, String name) throws IOException {
+ this(dir, name, BufferedIndexInput.BUFFER_SIZE);
+ }
+
+ public CompoundFileReader(Directory dir, String name, int readBufferSize) throws IOException {
+ assert !(dir instanceof CompoundFileReader) : "compound file inside of compound file: " + name;
+ directory = dir;
+ fileName = name;
+ this.readBufferSize = readBufferSize;
+
+ boolean success = false;
+
+ try {
+ stream = dir.openInput(name, readBufferSize);
+
+ // read the first VInt. If it is negative, it's the version number
+ // otherwise it's the count (pre-3.1 indexes)
+ int firstInt = stream.readVInt();
+
+ final int count;
+ final boolean stripSegmentName;
+ if (firstInt < CompoundFileWriter.FORMAT_PRE_VERSION) {
+ if (firstInt < CompoundFileWriter.FORMAT_CURRENT) {
+ throw new CorruptIndexException("Incompatible format version: "
+ + firstInt + " expected " + CompoundFileWriter.FORMAT_CURRENT + " (resource: " + stream + ")");
+ }
+ // It's a post-3.1 index, read the count.
+ count = stream.readVInt();
+ stripSegmentName = false;
+ } else {
+ count = firstInt;
+ stripSegmentName = true;
+ }
+
+ // read the directory and init files
+ FileEntry entry = null;
+ for (int i=0; i<count; i++) {
+ long offset = stream.readLong();
+ String id = stream.readString();
+
+ if (stripSegmentName) {
+ // Fix the id to not include the segment names. This is relevant for
+ // pre-3.1 indexes.
+ id = IndexFileNames.stripSegmentName(id);
+ }
+
+ if (entry != null) {
+ // set length of the previous entry
+ entry.length = offset - entry.offset;
+ }
+
+ entry = new FileEntry();
+ entry.offset = offset;
+ entries.put(id, entry);
+ }
+
+ // set the length of the final entry
+ if (entry != null) {
+ entry.length = stream.length() - entry.offset;
+ }
+
+ success = true;
+
+ } finally {
+ if (!success && (stream != null)) {
+ try {
+ stream.close();
+ } catch (IOException e) { }
+ }
+ }
+ }
+
+ public Directory getDirectory() {
+ return directory;
+ }
+
+ public String getName() {
+ return fileName;
+ }
+
+ @Override
+ public synchronized void close() throws IOException {
+ if (stream == null)
+ throw new IOException("Already closed");
+
+ entries.clear();
+ stream.close();
+ stream = null;
+ }
+
+ @Override
+ public synchronized IndexInput openInput(String id) throws IOException {
+ // Default to readBufferSize passed in when we were opened
+ return openInput(id, readBufferSize);
+ }
+
+ @Override
+ public synchronized IndexInput openInput(String id, int readBufferSize) throws IOException {
+ if (stream == null)
+ throw new IOException("Stream closed");
+
+ id = IndexFileNames.stripSegmentName(id);
+ FileEntry entry = entries.get(id);
+ if (entry == null) {
+ throw new IOException("No sub-file with id " + id + " found (fileName=" + fileName + " files: " + entries.keySet() + ")");
+ }
+
+ return new CSIndexInput(stream, entry.offset, entry.length, readBufferSize);
+ }
+
+ /** Returns an array of strings, one for each file in the directory. */
+ @Override
+ public String[] listAll() {
+ String[] res = entries.keySet().toArray(new String[entries.size()]);
+ // Add the segment name
+ String seg = fileName.substring(0, fileName.indexOf('.'));
+ for (int i = 0; i < res.length; i++) {
+ res[i] = seg + res[i];
+ }
+ return res;
+ }
+
+ /** Returns true iff a file with the given name exists. */
+ @Override
+ public boolean fileExists(String name) {
+ return entries.containsKey(IndexFileNames.stripSegmentName(name));
+ }
+
+ /** Returns the time the compound file was last modified. */
+ @Override
+ public long fileModified(String name) throws IOException {
+ return directory.fileModified(fileName);
+ }
+
+ /** Set the modified time of the compound file to now.
+ * @deprecated Lucene never uses this API; it will be
+ * removed in 4.0. */
+ @Override
+ @Deprecated
+ public void touchFile(String name) throws IOException {
+ directory.touchFile(fileName);
+ }
+
+ /** Not implemented
+ * @throws UnsupportedOperationException */
+ @Override
+ public void deleteFile(String name) {
+ throw new UnsupportedOperationException();
+ }
+
+ /** Not implemented
+ * @throws UnsupportedOperationException */
+ public void renameFile(String from, String to) {
+ throw new UnsupportedOperationException();
+ }
+
+ /** Returns the length of a file in the directory.
+ * @throws IOException if the file does not exist */
+ @Override
+ public long fileLength(String name) throws IOException {
+ FileEntry e = entries.get(IndexFileNames.stripSegmentName(name));
+ if (e == null)
+ throw new FileNotFoundException(name);
+ return e.length;
+ }
+
+ /** Not implemented
+ * @throws UnsupportedOperationException */
+ @Override
+ public IndexOutput createOutput(String name) {
+ throw new UnsupportedOperationException();
+ }
+
+ /** Not implemented
+ * @throws UnsupportedOperationException */
+ @Override
+ public Lock makeLock(String name) {
+ throw new UnsupportedOperationException();
+ }
+
+ /** Implementation of an IndexInput that reads from a portion of the
+ * compound file. The visibility is left as "package" *only* because
+ * this helps with testing since JUnit test cases in a different class
+ * can then access package fields of this class.
+ */
+ static final class CSIndexInput extends BufferedIndexInput {
+ IndexInput base;
+ long fileOffset;
+ long length;
+
+ CSIndexInput(final IndexInput base, final long fileOffset, final long length) {
+ this(base, fileOffset, length, BufferedIndexInput.BUFFER_SIZE);
+ }
+
+ CSIndexInput(final IndexInput base, final long fileOffset, final long length, int readBufferSize) {
+ super(readBufferSize);
+ this.base = (IndexInput)base.clone();
+ this.fileOffset = fileOffset;
+ this.length = length;
+ }
+
+ @Override
+ public Object clone() {
+ CSIndexInput clone = (CSIndexInput)super.clone();
+ clone.base = (IndexInput)base.clone();
+ clone.fileOffset = fileOffset;
+ clone.length = length;
+ return clone;
+ }
+
+ /** Expert: implements buffer refill. Reads bytes from the current
+ * position in the input.
+ * @param b the array to read bytes into
+ * @param offset the offset in the array to start storing bytes
+ * @param len the number of bytes to read
+ */
+ @Override
+ protected void readInternal(byte[] b, int offset, int len) throws IOException {
+ long start = getFilePointer();
+ if(start + len > length)
+ throw new EOFException("read past EOF (resource: " + base + ")");
+ base.seek(fileOffset + start);
+ base.readBytes(b, offset, len, false);
+ }
+
+ /** Expert: implements seek. Sets current position in this file, where
+ * the next {@link #readInternal(byte[],int,int)} will occur.
+ * @see #readInternal(byte[],int,int)
+ */
+ @Override
+ protected void seekInternal(long pos) {}
+
+ /** Closes the stream to further operations. */
+ @Override
+ public void close() throws IOException {
+ base.close();
+ }
+
+ @Override
+ public long length() {
+ return length;
+ }
+
+ @Override
+ public void copyBytes(IndexOutput out, long numBytes) throws IOException {
+ // Copy first whatever is in the buffer
+ numBytes -= flushBuffer(out, numBytes);
+
+ // If there are more bytes left to copy, delegate the copy task to the
+ // base IndexInput, in case it can do an optimized copy.
+ if (numBytes > 0) {
+ long start = getFilePointer();
+ if (start + numBytes > length) {
+ throw new EOFException("read past EOF (resource: " + base + ")");
+ }
+ base.seek(fileOffset + start);
+ base.copyBytes(out, numBytes);
+ }
+ }
+ }
+}
fnp / pylucene.git / blobdiff