/*******************************************************************************
* Copyright (c) 2000, 2012 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.mylyn.internal.commons.core;
import java.io.IOException;
import java.io.PushbackReader;
import java.io.Reader;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
/**
* Reads the text contents from a reader of HTML contents and translates the tags or cut them out.
* <p>
* Moved into this package from <code>org.eclipse.jface.internal.text.revisions</code>.
* </p>
* <p>
* Based on {@link org.eclipse.jface.internal.text.html.HTML2TextReader}.
* </p>
*/
@SuppressWarnings({ "rawtypes", "unchecked" })
public class Html2TextReader extends SubstitutionTextReader {
private static final String EMPTY_STRING = ""; //$NON-NLS-1$
private static final Map fgEntityLookup;
private static final Set fgTags;
static {
fgTags = new HashSet();
fgTags.add("b"); //$NON-NLS-1$
fgTags.add("br"); //$NON-NLS-1$
fgTags.add("br/"); //$NON-NLS-1$
fgTags.add("div"); //$NON-NLS-1$
fgTags.add("h1"); //$NON-NLS-1$
fgTags.add("h2"); //$NON-NLS-1$
fgTags.add("h3"); //$NON-NLS-1$
fgTags.add("h4"); //$NON-NLS-1$
fgTags.add("h5"); //$NON-NLS-1$
fgTags.add("p"); //$NON-NLS-1$
fgTags.add("dl"); //$NON-NLS-1$
fgTags.add("dt"); //$NON-NLS-1$
fgTags.add("dd"); //$NON-NLS-1$
fgTags.add("li"); //$NON-NLS-1$
fgTags.add("ul"); //$NON-NLS-1$
fgTags.add("pre"); //$NON-NLS-1$
fgTags.add("head"); //$NON-NLS-1$
fgEntityLookup = new HashMap(7);
fgEntityLookup.put("lt", "<"); //$NON-NLS-1$ //$NON-NLS-2$
fgEntityLookup.put("gt", ">"); //$NON-NLS-1$ //$NON-NLS-2$
fgEntityLookup.put("nbsp", " "); //$NON-NLS-1$ //$NON-NLS-2$
fgEntityLookup.put("amp", "&"); //$NON-NLS-1$ //$NON-NLS-2$
fgEntityLookup.put("circ", "^"); //$NON-NLS-1$ //$NON-NLS-2$
fgEntityLookup.put("tilde", "~"); //$NON-NLS-1$ //$NON-NLS-2$
fgEntityLookup.put("quot", "\""); //$NON-NLS-1$ //$NON-NLS-2$
}
private boolean fInParagraph = false;
private boolean fIsPreformattedText = false;
private boolean fIgnore = false;
/**
* Transforms the HTML text from the reader to formatted text.
*
* @param reader
* the reader
* @param presentation
* If not <code>null</code>, formattings will be applied to the presentation.
*/
public Html2TextReader(Reader reader) {
super(new PushbackReader(reader));
}
protected void startBold() {
}
protected void startPreformattedText() {
fIsPreformattedText = true;
//setSkipWhitespace(false);
}
protected void stopPreformattedText() {
fIsPreformattedText = false;
//setSkipWhitespace(true);
}
protected void stopBold() {
}
/*
* @see org.eclipse.jdt.internal.ui.text.SubstitutionTextReader#computeSubstitution(int)
*/
@Override
protected String computeSubstitution(int c) throws IOException {
if (c == '<') {
return processHTMLTag();
} else if (fIgnore) {
return EMPTY_STRING;
} else if (c == '&') {
return processEntity();
} else if (fIsPreformattedText) {
return processPreformattedText(c);
} else if (c == '\n') {
return EMPTY_STRING;
}
return null;
}
private String html2Text(String html) {
if (html == null || html.length() == 0) {
return EMPTY_STRING;
}
html = html.toLowerCase(Locale.ENGLISH);
String tag = html;
if ('/' == tag.charAt(0)) {
tag = tag.substring(1);
}
if (!fgTags.contains(tag)) {
return EMPTY_STRING;
}
if ("pre".equals(html)) { //$NON-NLS-1$
startPreformattedText();
return EMPTY_STRING;
}
if ("/pre".equals(html)) { //$NON-NLS-1$
stopPreformattedText();
return EMPTY_STRING;
}
if (fIsPreformattedText) {
return EMPTY_STRING;
}
if ("b".equals(html)) { //$NON-NLS-1$
startBold();
return EMPTY_STRING;
}
if ((html.length() > 1 && html.charAt(0) == 'h' && Character.isDigit(html.charAt(1))) || "dt".equals(html)) { //$NON-NLS-1$
startBold();
return EMPTY_STRING;
}
if ("dl".equals(html)) { //$NON-NLS-1$
return LINE_DELIM;
}
if ("dd".equals(html)) { //$NON-NLS-1$
return "\t"; //$NON-NLS-1$
}
if ("li".equals(html)) { //$NON-NLS-1$
return LINE_DELIM + " - "; //$NON-NLS-1$
}
if ("/b".equals(html)) { //$NON-NLS-1$
stopBold();
return EMPTY_STRING;
}
if ("p".equals(html)) { //$NON-NLS-1$
fInParagraph = true;
return LINE_DELIM;
}
if ("br".equals(html) || "br/".equals(html) || "div".equals(html)) { //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
return LINE_DELIM;
}
if ("/p".equals(html)) { //$NON-NLS-1$
boolean inParagraph = fInParagraph;
fInParagraph = false;
return inParagraph ? EMPTY_STRING : LINE_DELIM;
}
if ((html.startsWith("/h") && html.length() > 2 && Character.isDigit(html.charAt(2))) || "/dt".equals(html)) { //$NON-NLS-1$ //$NON-NLS-2$
stopBold();
return LINE_DELIM;
}
if ("/dd".equals(html)) { //$NON-NLS-1$
return LINE_DELIM;
}
if ("head".equals(html)) { //$NON-NLS-1$
fIgnore = true;
return EMPTY_STRING;
}
if ("/head".equals(html)) { //$NON-NLS-1$
fIgnore = false;
return EMPTY_STRING;
}
return EMPTY_STRING;
}
/*
* A '<' has been read. Process a html tag
*/
private String processHTMLTag() throws IOException {
StringBuilder buf = new StringBuilder();
int ch;
do {
ch = nextChar();
while (ch != -1 && ch != '>') {
buf.append(Character.toLowerCase((char) ch));
ch = nextChar();
if (ch == '"') {
buf.append(Character.toLowerCase((char) ch));
ch = nextChar();
while (ch != -1 && ch != '"') {
buf.append(Character.toLowerCase((char) ch));
ch = nextChar();
}
}
if (ch == '<') {
unread(ch);
return '<' + buf.toString();
}
}
if (ch == -1) {
return null;
}
int tagLen = buf.length();
// needs special treatment for comments
if ((tagLen >= 3 && "!--".equals(buf.substring(0, 3))) //$NON-NLS-1$
&& !(tagLen >= 5 && "--".equals(buf.substring(tagLen - 2)))) { //$NON-NLS-1$
// unfinished comment
buf.append(ch);
} else {
break;
}
} while (true);
return html2Text(buf.toString());
}
private String processPreformattedText(int c) {
return null;
}
private void unread(int ch) throws IOException {
((PushbackReader) getReader()).unread(ch);
}
protected String entity2Text(String symbol) {
if (symbol.length() > 1 && symbol.charAt(0) == '#') {
int ch;
try {
if (symbol.charAt(1) == 'x') {
ch = Integer.parseInt(symbol.substring(2), 16);
} else {
ch = Integer.parseInt(symbol.substring(1), 10);
}
return EMPTY_STRING + (char) ch;
} catch (NumberFormatException e) {
}
} else {
String str = (String) fgEntityLookup.get(symbol);
if (str != null) {
return str;
}
}
return "&" + symbol + ";"; // not found //$NON-NLS-1$ //$NON-NLS-2$
}
/*
* A '&' has been read. Process a entity
*/
private String processEntity() throws IOException {
StringBuilder buf = new StringBuilder();
int ch = nextChar();
while (Character.isLetterOrDigit((char) ch) || ch == '#') {
buf.append((char) ch);
ch = nextChar();
}
if (ch == ';') {
return entity2Text(buf.toString());
}
buf.insert(0, '&');
if (ch != -1) {
buf.append((char) ch);
}
return buf.toString();
}
}