| /******************************************************************************* |
| * Copyright (c) 2000, 2017 IBM Corporation and others. |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Public License v. 2.0 which is available at |
| * http://www.eclipse.org/legal/epl-2.0. |
| * |
| * SPDX-License-Identifier: EPL-2.0 |
| * |
| *******************************************************************************/ |
| package org.eclipse.dltk.internal.ui.text; |
| |
| 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.dltk.internal.ui.DLTKUIMessages; |
| 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. |
| */ |
| 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", "~"); //$NON-NLS-2$ //$NON-NLS-1$ |
| 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; |
| |
| /** |
| * 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; |
| } |
| |
| protected void startBold() { |
| if (fBold == 0) |
| fStartOffset = fCounter; |
| ++fBold; |
| } |
| |
| protected void startPreformattedText() { |
| fIsPreformattedText = true; |
| setSkipWhitespace(false); |
| } |
| |
| protected void stopPreformattedText() { |
| fIsPreformattedText = false; |
| setSkipWhitespace(true); |
| } |
| |
| protected void stopBold() { |
| --fBold; |
| if (fBold == 0) { |
| if (fTextPresentation != null) { |
| fTextPresentation.addStyleRange(new StyleRange(fStartOffset, |
| fCounter - fStartOffset, null, null, SWT.BOLD)); |
| } |
| fStartOffset = -1; |
| } |
| } |
| |
| @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; |
| } |
| |
| 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)) //$NON-NLS-1$ |
| 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 + DLTKUIMessages.HTML2TextReader_listItemPrefix; |
| |
| 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 { |
| |
| 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); |
| } |
| |
| 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 //$NON-NLS-1$ |
| } |
| |
| /* |
| * 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(); |
| } |
| } |
