Java tutorial
/* * 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. */ package org.apache.tika.parser.apple; import java.io.IOException; import java.io.InputStream; import java.nio.charset.StandardCharsets; import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.List; import java.util.Set; import org.apache.commons.io.IOUtils; import org.apache.commons.io.input.CloseShieldInputStream; import org.apache.tika.exception.TikaException; import org.apache.tika.extractor.EmbeddedDocumentExtractor; import org.apache.tika.extractor.EmbeddedDocumentUtil; import org.apache.tika.io.EndianUtils; import org.apache.tika.metadata.Metadata; import org.apache.tika.metadata.TikaCoreProperties; import org.apache.tika.mime.MediaType; import org.apache.tika.parser.AbstractParser; import org.apache.tika.parser.ParseContext; import org.apache.tika.sax.XHTMLContentHandler; import org.xml.sax.ContentHandler; import org.xml.sax.SAXException; /** * Parser that strips the header off of AppleSingle and AppleDouble * files. * <p> * See <a href="http://kaiser-edv.de/documents/AppleSingle_AppleDouble.pdf">spec document</a>. */ public class AppleSingleFileParser extends AbstractParser { /** * Entry types */ private static final int DATA_FORK = 1; private static final int RESOURCE_FORK = 2; private static final int REAL_NAME = 3; private static final int COMMENT = 4; private static final int ICON_BW = 5; private static final int ICON_COLOR = 6; //7?! private static final int FILE_DATES_INFO = 8; private static final int FINDER_INFO = 9; private static final int MACINTOSH_FILE_INFO = 10; private static final int PRODOS_FILE_INFO = 11; private static final int MSDOS_FILE_INFO = 12; private static final int SHORT_NAME = 13; private static final int AFP_FILE_INFO = 14; private static final int DIRECTORY_ID = 15; private static final Set<MediaType> SUPPORTED_TYPES = Collections.singleton(MediaType.application("applefile")); public Set<MediaType> getSupportedTypes(ParseContext context) { return SUPPORTED_TYPES; } @Override public void parse(InputStream stream, ContentHandler handler, Metadata metadata, ParseContext context) throws IOException, SAXException, TikaException { EmbeddedDocumentExtractor ex = EmbeddedDocumentUtil.getEmbeddedDocumentExtractor(context); short numEntries = readThroughNumEntries(stream); long bytesRead = 26; List<FieldInfo> fieldInfoList = getSortedFieldInfoList(stream, numEntries); bytesRead += 12 * numEntries; Metadata embeddedMetadata = new Metadata(); bytesRead = processFieldEntries(stream, fieldInfoList, embeddedMetadata, bytesRead); FieldInfo contentFieldInfo = getContentFieldInfo(fieldInfoList); XHTMLContentHandler xhtml = new XHTMLContentHandler(handler, metadata); xhtml.startDocument(); if (contentFieldInfo != null) { long diff = contentFieldInfo.offset - bytesRead; IOUtils.skipFully(stream, diff); if (ex.shouldParseEmbedded(embeddedMetadata)) { // TODO: we should probably add a readlimiting wrapper around this // stream to ensure that not more than contentFieldInfo.length bytes // are read ex.parseEmbedded(new CloseShieldInputStream(stream), xhtml, embeddedMetadata, false); } } xhtml.endDocument(); } private FieldInfo getContentFieldInfo(List<FieldInfo> fieldInfoList) { for (FieldInfo fieldInfo : fieldInfoList) { if (fieldInfo.entryId == 1) { return fieldInfo; } } return null; } private long processFieldEntries(InputStream stream, List<FieldInfo> fieldInfoList, Metadata embeddedMetadata, long bytesRead) throws IOException, TikaException { byte[] buffer = null; for (FieldInfo f : fieldInfoList) { long diff = f.offset - bytesRead; //just in case IOUtils.skipFully(stream, diff); bytesRead += diff; if (f.entryId == REAL_NAME) { if (f.length > Integer.MAX_VALUE) { throw new TikaException("File name length can't be > integer max"); } buffer = new byte[(int) f.length]; IOUtils.readFully(stream, buffer); bytesRead += f.length; String originalFileName = new String(buffer, 0, buffer.length, StandardCharsets.US_ASCII); embeddedMetadata.set(TikaCoreProperties.ORIGINAL_RESOURCE_NAME, originalFileName); } else if (f.entryId != DATA_FORK) { IOUtils.skipFully(stream, f.length); bytesRead += f.length; } } return bytesRead; } private List<FieldInfo> getSortedFieldInfoList(InputStream stream, short numEntries) throws IOException, TikaException { //this is probably overkill. I'd hope that these were already //in order. This ensures it. List<FieldInfo> fieldInfoList = new ArrayList<>(numEntries); for (int i = 0; i < numEntries; i++) { //convert 32-bit unsigned ints to longs fieldInfoList.add(new FieldInfo(EndianUtils.readUIntBE(stream), //entry id EndianUtils.readUIntBE(stream), //offset EndianUtils.readUIntBE(stream) //length )); } if (fieldInfoList.size() == 0) { throw new TikaException("AppleSingleFile missing field info"); } //make absolutely sure these are in order! Collections.sort(fieldInfoList, new FieldInfoComparator()); return fieldInfoList; } //read through header until you hit the number of entries private short readThroughNumEntries(InputStream stream) throws TikaException, IOException { //mime EndianUtils.readIntBE(stream); //version long version = EndianUtils.readIntBE(stream); if (version != 0x00020000) { throw new TikaException("Version should have been 0x00020000, but was:" + version); } IOUtils.skipFully(stream, 16);//filler return EndianUtils.readShortBE(stream);//number of entries } private class FieldInfo { private final long entryId; private final long offset; private final long length; private FieldInfo(long entryId, long offset, long length) { this.entryId = entryId; this.offset = offset; this.length = length; } } private static class FieldInfoComparator implements Comparator<FieldInfo> { @Override public int compare(FieldInfo o1, FieldInfo o2) { return (o1.offset > o2.offset) ? 1 : (o1.offset == o2.offset) ? 0 : -1; } } }