tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-microsoft-module/src/main/java/org/apache/tika/parser/microsoft/EMFParser.java

/*
 * 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.microsoft;

import java.io.IOException;
import java.io.InputStream;
import java.util.Collections;
import java.util.Set;

import org.apache.poi.hemf.record.emf.HemfComment;
import org.apache.poi.hemf.record.emf.HemfRecord;
import org.apache.poi.hemf.record.emf.HemfRecordType;
import org.apache.poi.hemf.record.emf.HemfText;
import org.apache.poi.hemf.usermodel.HemfPicture;
import org.apache.poi.util.RecordFormatException;
import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;

import org.apache.tika.exception.TikaException;
import org.apache.tika.extractor.EmbeddedDocumentExtractor;
import org.apache.tika.extractor.EmbeddedDocumentUtil;
import org.apache.tika.io.TikaInputStream;
import org.apache.tika.metadata.Metadata;
import org.apache.tika.mime.MediaType;
import org.apache.tika.parser.AbstractParser;
import org.apache.tika.parser.ParseContext;
import org.apache.tika.sax.EmbeddedContentHandler;
import org.apache.tika.sax.XHTMLContentHandler;

/**
 * Extracts files embedded in EMF and offers a
 * very rough capability to extract text if there
 * is text stored in the EMF.
 * <p/>
 * To improve text extraction, we'd have to implement
 * quite a bit more at the POI level.  We'd want to track changes
 * in font and use that information for identifying character sets,
 * inserting spaces and new lines.
 */
public class EMFParser extends AbstractParser {

    private static final MediaType MEDIA_TYPE = MediaType.image("emf");
    private static final MediaType WMF_MEDIA_TYPE = MediaType.image("wmf");

    private static final Set<MediaType> SUPPORTED_TYPES = Collections.singleton(MEDIA_TYPE);

    private static void handleEmbedded(byte[] data,
                                       EmbeddedDocumentExtractor embeddedDocumentExtractor,
                                       ContentHandler handler) throws TikaException, SAXException {
        try (InputStream is = TikaInputStream.get(data)) {
            Metadata embeddedMetadata = new Metadata();
            if (embeddedDocumentExtractor.shouldParseEmbedded(embeddedMetadata)) {
                embeddedDocumentExtractor
                        .parseEmbedded(is, new EmbeddedContentHandler(handler), embeddedMetadata,
                                false);
            }
        } catch (IOException e) {
            //swallow
        }
    }

    @Override
    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 embeddedDocumentExtractor = null;
        XHTMLContentHandler xhtml = new XHTMLContentHandler(handler, metadata);
        xhtml.startDocument();
        try {
            HemfPicture ex = new HemfPicture(stream);
            double lastY = -1;
            double lastX = -1;
            long fudgeFactorX = 1000;//derive this from the font or frame/bounds information
            StringBuilder buffer = new StringBuilder();
            for (HemfRecord record : ex) {
                if (record.getEmfRecordType() == HemfRecordType.comment) {
                    HemfComment.EmfCommentData commentData =
                            ((HemfComment.EmfComment) record).getCommentData();
                    if (commentData instanceof HemfComment.EmfCommentDataMultiformats) {
                        if (embeddedDocumentExtractor == null) {
                            embeddedDocumentExtractor =
                                    EmbeddedDocumentUtil.getEmbeddedDocumentExtractor(context);
                        }
                        handleMultiFormats((HemfComment.EmfCommentDataMultiformats) commentData,
                                xhtml, embeddedDocumentExtractor);
                    } else if (commentData instanceof HemfComment.EmfCommentDataWMF) {
                        if (embeddedDocumentExtractor == null) {
                            embeddedDocumentExtractor =
                                    EmbeddedDocumentUtil.getEmbeddedDocumentExtractor(context);
                        }
                        handleWMF(((HemfComment.EmfCommentDataWMF) commentData).getWMFData(), xhtml,
                                embeddedDocumentExtractor);
                    }
                } else if (record.getEmfRecordType().equals(HemfRecordType.extTextOutW)) {

                    HemfText.EmfExtTextOutW extTextOutW = (HemfText.EmfExtTextOutW) record;
                    //change equality to delta diff;

                    if (lastY > -1 && lastY != extTextOutW.getReference().getY()) {
                        xhtml.startElement("p");
                        xhtml.characters(buffer.toString());
                        xhtml.endElement("p");
                        buffer.setLength(0);
                        lastX = -1;
                    }
                    if (lastX > -1 && extTextOutW.getReference().getX() - lastX > fudgeFactorX) {
                        buffer.append(" ");
                    }
                    String txt = extTextOutW.getText();
                    buffer.append(txt);
                    lastY = extTextOutW.getReference().getY();
                    lastX = extTextOutW.getReference().getX();
                }
            }
            if (buffer.length() > 0) {
                xhtml.startElement("p");
                xhtml.characters(buffer.toString());
                xhtml.endElement("p");
            }
        } catch (RecordFormatException e) { //POI's hemfparser can throw these for "parse
            // exceptions"
            throw new TikaException(e.getMessage(), e);
        } catch (RuntimeException e) { //convert Runtime to RecordFormatExceptions
            throw new TikaException(e.getMessage(), e);
        }
        xhtml.endDocument();
    }

    private void handleWMF(byte[] bytes, ContentHandler contentHandler,
                           EmbeddedDocumentExtractor embeddedDocumentExtractor)
            throws IOException, SAXException, TikaException {
        Metadata embeddedMetadata = new Metadata();
        embeddedMetadata.set(Metadata.CONTENT_TYPE, WMF_MEDIA_TYPE.toString());
        if (embeddedDocumentExtractor.shouldParseEmbedded(embeddedMetadata)) {
            try (InputStream is = TikaInputStream.get(bytes)) {
                embeddedDocumentExtractor
                        .parseEmbedded(is, new EmbeddedContentHandler(contentHandler),
                                embeddedMetadata, false);

            }

        }

    }

    private void handleMultiFormats(HemfComment.EmfCommentDataMultiformats commentData,
                                    ContentHandler handler,
                                    EmbeddedDocumentExtractor embeddedDocumentExtractor)
            throws IOException, TikaException, SAXException {

        for (HemfComment.EmfCommentDataFormat dataFormat : commentData.getFormats()) {
            //is this right?!
            handleEmbedded(dataFormat.getRawData(), embeddedDocumentExtractor, handler);
        }
    }
}