/*
* Copyright (c) 2011, the Dart project authors.
*
* Licensed under the Eclipse Public License v1.0 (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.eclipse.org/legal/epl-v10.html
*
* 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 com.google.dart.tools.ui.internal.text.html;
import org.eclipse.jface.text.TextPresentation;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.StyleRange;
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;
/**
* 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("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 fStartOffset = -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;
}
@Override
public int read() throws IOException {
int c = super.read();
if (c != -1) {
++fCounter;
}
return c;
}
/*
* @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);
}
return null;
}
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 = fgEntityLookup.get(symbol);
if (str != null) {
return str;
}
}
return "&" + symbol; // not found //$NON-NLS-1$
}
protected void startBold() {
if (fBold == 0) {
fStartOffset = fCounter;
}
++fBold;
}
protected void startPreformattedText() {
fIsPreformattedText = true;
setSkipWhitespace(false);
}
protected void stopBold() {
--fBold;
if (fBold == 0) {
if (fTextPresentation != null) {
fTextPresentation.addStyleRange(new StyleRange(
fStartOffset,
fCounter - fStartOffset,
null,
null,
SWT.BOLD));
}
fStartOffset = -1;
}
}
protected void stopPreformattedText() {
fIsPreformattedText = false;
setSkipWhitespace(true);
}
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 ((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)) {
return LINE_DELIM;
}
if ("dd".equals(html)) {
return "\t"; //$NON-NLS-1$
}
if ("li".equals(html)) {
// 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 ("p".equals(html)) { //$NON-NLS-1$
fInParagraph = true;
return LINE_DELIM;
}
if ("br".equals(html) || "br/".equals(html) || "div".equals(html)) {
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)) {
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 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();
}
/*
* 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 == '<') {
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) {
if (c == '\r' || c == '\n') {
fCounter++;
}
return null;
}
private void unread(int ch) throws IOException {
((PushbackReader) getReader()).unread(ch);
}
}