/*******************************************************************************
* 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 au.gov.ga.earthsci.jface.extras.information.html;
import java.io.IOException;
import java.io.PushbackReader;
import java.io.Reader;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import org.eclipse.jface.text.TextPresentation;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.StyleRange;
/**
* 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>
*/
public class HTML2TextReader extends SubstitutionTextReader {
private static final String EMPTY_STRING= ""; //$NON-NLS-1$
private static final Map<String, String> fgEntityLookup;
private static final Set<String> fgTags;
static {
fgTags= new HashSet<String>();
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("del"); //$NON-NLS-1$
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<String, String>(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", "~"); //$NON-NLS-2$ //$NON-NLS-1$
fgEntityLookup.put("quot", "\""); //$NON-NLS-1$ //$NON-NLS-2$
}
private int fCounter= 0;
private TextPresentation fTextPresentation;
private int fBold= 0;
private int fBoldStartOffset= -1;
private int fStrikeout= 0;
private int fStrikeoutStartOffset= -1;
private boolean fInParagraph= false;
private boolean fIsPreformattedText= false;
private boolean fIgnore= false;
private boolean fHeaderDetected= 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, TextPresentation presentation) {
super(new PushbackReader(reader));
fTextPresentation= presentation;
}
public int read() throws IOException {
int c= super.read();
if (c != -1)
++ fCounter;
return c;
}
private void setBold(int offset, int length) {
if (fTextPresentation != null && offset >= 0 && length > 0) {
fTextPresentation.addStyleRange(new StyleRange(offset, length, null, null, SWT.BOLD));
}
}
private void setStrikeout(int offset, int length) {
if (fTextPresentation != null && offset >= 0 && length > 0) {
StyleRange styleRange= new StyleRange(offset, length, null, null, SWT.NORMAL);
styleRange.strikeout= true;
fTextPresentation.addStyleRange(styleRange);
}
}
private void setBoldAndStrikeOut(int offset, int length) {
if (fTextPresentation != null && offset >= 0 && length > 0) {
StyleRange styleRange= new StyleRange(offset, length, null, null, SWT.BOLD);
styleRange.strikeout= true;
fTextPresentation.addStyleRange(styleRange);
}
}
protected void startBold() {
if (fBold == 0) {
fBoldStartOffset= fCounter;
if (fStrikeout > 0) {
setStrikeout(fStrikeoutStartOffset, fCounter - fStrikeoutStartOffset);
}
}
++fBold;
}
protected void stopBold() {
--fBold;
if (fBold == 0) {
if (fStrikeout == 0) {
setBold(fBoldStartOffset, fCounter - fBoldStartOffset);
} else {
setBoldAndStrikeOut(fBoldStartOffset, fCounter - fBoldStartOffset);
fStrikeoutStartOffset= fCounter;
}
fBoldStartOffset= -1;
}
}
protected void startStrikeout() {
if (fStrikeout == 0) {
fStrikeoutStartOffset= fCounter;
if (fBold > 0) {
setBold(fBoldStartOffset, fCounter - fBoldStartOffset);
}
}
++fStrikeout;
}
protected void stopStrikeout() {
--fStrikeout;
if (fStrikeout == 0) {
if (fBold == 0) {
setStrikeout(fStrikeoutStartOffset, fCounter - fStrikeoutStartOffset);
} else {
setBoldAndStrikeOut(fStrikeoutStartOffset, fCounter - fStrikeoutStartOffset);
fBoldStartOffset= fCounter;
}
fStrikeoutStartOffset= -1;
}
}
protected void startPreformattedText() {
fIsPreformattedText= true;
setSkipWhitespace(false);
}
protected void stopPreformattedText() {
fIsPreformattedText= false;
setSkipWhitespace(true);
}
/*
* @see org.eclipse.jdt.internal.ui.text.SubstitutionTextReader#computeSubstitution(int)
*/
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);
return null;
}
private String html2Text(String html) {
if (html == null || html.length() == 0)
return EMPTY_STRING;
html= html.toLowerCase();
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 ("del".equals(html)) { //$NON-NLS-1$
startStrikeout();
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)) //$NON-NLS-1$
// FIXME: this hard-coded prefix does not work for RTL languages, see https://bugs.eclipse.org/bugs/show_bug.cgi?id=91682
return LINE_DELIM + HTMLMessages.getString("HTML2TextReader.listItemPrefix"); //$NON-NLS-1$
if ("/b".equals(html)) { //$NON-NLS-1$
stopBold();
return EMPTY_STRING;
}
if ("/del".equals(html)) { //$NON-NLS-1$
stopStrikeout();
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) && !fHeaderDetected) { //$NON-NLS-1$
fHeaderDetected= true;
fIgnore= true;
return EMPTY_STRING;
}
if ("/head".equals(html) && fHeaderDetected && fIgnore) { //$NON-NLS-1$
fIgnore= false;
return EMPTY_STRING;
}
return EMPTY_STRING;
}
/*
* A '<' has been read. Process a html tag
*/
private String processHTMLTag() throws IOException {
StringBuffer buf= new StringBuffer();
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 == '<' && !isInComment(buf)) {
unread(ch);
return '<' + buf.toString();
}
}
if (ch == -1)
return null;
if (!isInComment(buf) || isCommentEnd(buf)) {
break;
}
// unfinished comment
buf.append((char) ch);
} while (true);
return html2Text(buf.toString());
}
private static boolean isInComment(StringBuffer buf) {
return buf.length() >= 3 && "!--".equals(buf.substring(0, 3)); //$NON-NLS-1$
}
private static boolean isCommentEnd(StringBuffer buf) {
int tagLen= buf.length();
return tagLen >= 5 && "--".equals(buf.substring(tagLen - 2)); //$NON-NLS-1$
}
private String processPreformattedText(int c) {
if (c == '\r' || c == '\n')
fCounter++;
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 {
StringBuffer buf= new StringBuffer();
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();
}
}