RTFHtmlDecapsulator.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.rtf.jflex;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;
import org.apache.tika.exception.TikaException;
import org.apache.tika.parser.ParseContext;
/**
* Extracts the original HTML from an RTF document that contains encapsulated HTML
* (as indicated by the {@code \fromhtml1} control word), using a JFlex-based tokenizer
* and shared {@link RTFState} for font/codepage tracking.
*
* <p>Embedded objects and pictures are extracted in the same pass via
* {@link RTFEmbeddedHandler}.</p>
*/
public class RTFHtmlDecapsulator {
private static final int DEFAULT_MAX_BYTES_KB = 2 * 1024 * 1024; // 2 GB
private final RTFEmbeddedHandler embHandler;
public RTFHtmlDecapsulator(ContentHandler handler, ParseContext context,
int maxBytesInKb) {
this.embHandler = new RTFEmbeddedHandler(handler, context, maxBytesInKb);
}
public RTFHtmlDecapsulator(ContentHandler handler, ParseContext context) {
this(handler, context, DEFAULT_MAX_BYTES_KB);
}
public String extract(byte[] rtfBytes) throws IOException, SAXException, TikaException {
if (rtfBytes == null || rtfBytes.length == 0) {
return null;
}
// Wrap byte[] in a Reader directly ��� RTF is 7-bit ASCII, so
// US_ASCII decoding is a 1:1 byte-to-char mapping with no
// intermediate String allocation.
Reader reader = new InputStreamReader(
new ByteArrayInputStream(rtfBytes), StandardCharsets.US_ASCII);
RTFTokenizer tokenizer = new RTFTokenizer(reader);
RTFState state = new RTFState();
StringBuilder html = new StringBuilder(rtfBytes.length / 2);
ByteArrayOutputStream pendingBytes = new ByteArrayOutputStream();
boolean foundFromHtml = false;
boolean foundHtmlTag = false;
boolean inHtmlRtfSkip = false;
boolean sawIgnorable = false;
int htmlTagDepth = -1;
boolean inHtmlTag = false;
RTFToken tok;
// EOF inside {\object or {\pict leaves a stream parser open
try {
while ((tok = tokenizer.yylex()) != null) {
RTFTokenType type = tok.getType();
if (type == RTFTokenType.EOF) {
break;
}
// Flush pending bytes before charset-changing events
if (type == RTFTokenType.GROUP_CLOSE
|| (type == RTFTokenType.CONTROL_WORD && "f".equals(tok.getName())
&& tok.hasParameter())) {
flushPendingBytes(pendingBytes, html, state);
}
boolean consumed = state.processToken(tok);
// Embedded handler processes objdata/pict/sp in the same pass
if (!consumed) {
RTFGroupState closingGroup =
(type == RTFTokenType.GROUP_CLOSE) ? state.getLastClosedGroup() : null;
try {
embHandler.processToken(tok, state, closingGroup);
} catch (TikaException | IOException e) {
// don't let a bad embedded object kill decapsulation
}
}
RTFGroupState group = state.getCurrentGroup();
// Skip tokens that are part of objdata/pict hex streams
if (!consumed && (group.objdata || group.pictDepth > 0)) {
continue;
}
switch (type) {
case GROUP_OPEN:
sawIgnorable = false;
break;
case GROUP_CLOSE:
if (inHtmlTag && state.getDepth() < htmlTagDepth) {
flushPendingBytes(pendingBytes, html, state);
inHtmlTag = false;
htmlTagDepth = -1;
}
break;
case CONTROL_SYMBOL:
if (tok.getChar() == '*') {
sawIgnorable = true;
}
if (!foundHtmlTag || inHtmlRtfSkip) {
break;
}
if (inHtmlTag || htmlTagDepth == -1) {
char sym = tok.getChar();
if (sym == '{' || sym == '}' || sym == '\\') {
flushPendingBytes(pendingBytes, html, state);
html.append(sym);
}
}
break;
case CONTROL_WORD:
if (consumed) {
break;
}
String name = tok.getName();
if ("fromhtml".equals(name)) {
foundFromHtml = true;
break;
}
if ("htmltag".equals(name) && sawIgnorable) {
if (!foundFromHtml) {
break;
}
foundHtmlTag = true;
flushPendingBytes(pendingBytes, html, state);
inHtmlTag = true;
htmlTagDepth = state.getDepth();
break;
}
if ("htmlrtf".equals(name)) {
flushPendingBytes(pendingBytes, html, state);
inHtmlRtfSkip = !(tok.hasParameter() && tok.getParameter() == 0);
break;
}
if (!foundHtmlTag || inHtmlRtfSkip) {
break;
}
if (inHtmlTag || htmlTagDepth == -1) {
flushPendingBytes(pendingBytes, html, state);
switch (name) {
case "par":
case "pard":
html.append('\n');
break;
case "tab":
html.append('\t');
break;
case "line":
html.append("<br>");
break;
default:
break;
}
}
break;
case HEX_ESCAPE:
if (consumed || !foundHtmlTag || inHtmlRtfSkip) {
break;
}
if (inHtmlTag || htmlTagDepth == -1) {
pendingBytes.write(tok.getHexValue());
}
break;
case UNICODE_ESCAPE:
if (!foundHtmlTag || inHtmlRtfSkip) {
break;
}
if (inHtmlTag || htmlTagDepth == -1) {
flushPendingBytes(pendingBytes, html, state);
int cp = tok.getParameter();
if (Character.isValidCodePoint(cp)) {
html.appendCodePoint(cp);
}
}
break;
case TEXT:
if (consumed || !foundHtmlTag || inHtmlRtfSkip) {
break;
}
if (inHtmlTag || htmlTagDepth == -1) {
flushPendingBytes(pendingBytes, html, state);
html.append(tok.getChar());
}
break;
default:
break;
}
}
} finally {
embHandler.close();
}
flushPendingBytes(pendingBytes, html, state);
if (!foundFromHtml || html.length() == 0) {
return null;
}
return html.toString();
}
private static void flushPendingBytes(ByteArrayOutputStream pending, StringBuilder out,
RTFState state) {
if (pending.size() > 0) {
Charset cs = state.getCurrentCharset();
out.append(new String(pending.toByteArray(), cs));
pending.reset();
}
}
}