src/main/java/net/pterodactylus/sone/text/SoneTextParser.java

   1 /*
   2  * Sone - SoneTextParser.java - Copyright © 2010–2013 David Roden
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 package net.pterodactylus.sone.text;
  19
  20 import static com.google.common.base.Optional.absent;
  21 import static com.google.common.base.Optional.of;
  22 import static com.google.common.collect.FluentIterable.from;
  23
  24 import java.io.BufferedReader;
  25 import java.io.IOException;
  26 import java.io.Reader;
  27 import java.net.MalformedURLException;
  28 import java.util.Comparator;
  29 import java.util.EnumMap;
  30 import java.util.Map.Entry;
  31 import java.util.logging.Level;
  32 import java.util.logging.Logger;
  33 import java.util.regex.Matcher;
  34 import java.util.regex.Pattern;
  35
  36 import net.pterodactylus.sone.data.Post;
  37 import net.pterodactylus.sone.data.Sone;
  38 import net.pterodactylus.sone.data.impl.DefaultSone;
  39 import net.pterodactylus.sone.database.Database;
  40 import net.pterodactylus.util.io.Closer;
  41 import net.pterodactylus.util.logging.Logging;
  42
  43 import com.google.common.base.Optional;
  44 import freenet.keys.FreenetURI;
  45
  46 /**
  47  * {@link Parser} implementation that can recognize Freenet URIs.
  48  *
  49  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  50  */
  51 public class SoneTextParser implements Parser<SoneTextParserContext> {
  52
  53         /** The logger. */
  54         private static final Logger logger = Logging.getLogger(SoneTextParser.class);
  55
  56         /** Pattern to detect whitespace. */
  57         private static final Pattern whitespacePattern = Pattern.compile("[\\u000a\u0020\u00a0\u1680\u180e\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u200b\u200c\u200d\u202f\u205f\u2060\u2800\u3000]");
  58
  59         /**
  60          * Enumeration for all recognized link types.
  61          *
  62          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  63          */
  64         private enum LinkType {
  65
  66                 /** Link is a KSK. */
  67                 KSK("KSK@", true, false),
  68
  69                 /** Link is a CHK. */
  70                 CHK("CHK@", true, false),
  71
  72                 /** Link is an SSK. */
  73                 SSK("SSK@", true, false),
  74
  75                 /** Link is a USK. */
  76                 USK("USK@", true, false),
  77
  78                 /** Link is HTTP. */
  79                 HTTP("http://", false, true),
  80
  81                 /** Link is HTTPS. */
  82                 HTTPS("https://", false, true),
  83
  84                 /** Link is a Sone. */
  85                 SONE("sone://", false, false),
  86
  87                 /** Link is a post. */
  88                 POST("post://", false, false);
  89
  90                 /** The scheme identifying this link type. */
  91                 private final String scheme;
  92                 private final boolean freenetLink;
  93                 private final boolean internetLink;
  94
  95                 /**
  96                  * Creates a new link type identified by the given scheme.
  97                  *
  98                  * @param scheme
  99                  *            The scheme of the link type
 100                  * @param freenetLink
 101                  */
 102                 private LinkType(String scheme, boolean freenetLink, boolean internetLink) {
 103                         this.scheme = scheme;
 104                         this.freenetLink = freenetLink;
 105                         this.internetLink = internetLink;
 106                 }
 107
 108                 /**
 109                  * Returns the scheme of this link type.
 110                  *
 111                  * @return The scheme of this link type
 112                  */
 113                 public String getScheme() {
 114                         return scheme;
 115                 }
 116
 117                 public boolean isFreenetLink() {
 118                         return freenetLink;
 119                 }
 120
 121                 public boolean isInternetLink() {
 122                         return internetLink;
 123                 }
 124
 125         }
 126
 127         private final Database database;
 128
 129         /**
 130          * Creates a new freenet link parser.
 131          *
 132          * @param database
 133          */
 134         public SoneTextParser(Database database) {
 135                 this.database = database;
 136         }
 137
 138         //
 139         // PART METHODS
 140         //
 141
 142         @Override
 143         public Iterable<Part> parse(SoneTextParserContext context, Reader source) throws IOException {
 144                 PartContainer parts = new PartContainer();
 145                 BufferedReader bufferedReader = (source instanceof BufferedReader) ? (BufferedReader) source : new BufferedReader(source);
 146                 try {
 147                         String line;
 148                         boolean lastLineEmpty = true;
 149                         int emptyLines = 0;
 150                         while ((line = bufferedReader.readLine()) != null) {
 151                                 if (line.trim().length() == 0) {
 152                                         if (lastLineEmpty) {
 153                                                 continue;
 154                                         }
 155                                         parts.add(new PlainTextPart("\n"));
 156                                         ++emptyLines;
 157                                         lastLineEmpty = emptyLines == 2;
 158                                         continue;
 159                                 }
 160                                 emptyLines = 0;
 161                                 /*
 162                                  * lineComplete tracks whether the block you are parsing is the
 163                                  * first block of the line. this is important because sometimes
 164                                  * you have to add an additional line break.
 165                                  */
 166                                 boolean lineComplete = true;
 167                                 while (line.length() > 0) {
 168                                         Optional<NextLink> nextLink = findNextLink(line);
 169                                         if (!nextLink.isPresent()) {
 170                                                 if (lineComplete && !lastLineEmpty) {
 171                                                         parts.add(new PlainTextPart("\n" + line));
 172                                                 } else {
 173                                                         parts.add(new PlainTextPart(line));
 174                                                 }
 175                                                 break;
 176                                         }
 177
 178                                         int next = nextLink.get().getNextIndex();
 179                                         LinkType linkType = nextLink.get().getLinkType();
 180
 181                                         /* cut off “freenet:” from before keys. */
 182                                         if (linkType.isFreenetLink() && (next >= 8) && (line.substring(next - 8, next).equals("freenet:"))) {
 183                                                 next -= 8;
 184                                                 line = line.substring(0, next) + line.substring(next + 8);
 185                                         }
 186
 187                                         /* if there is text before the next item, write it out. */
 188                                         if (lineComplete && !lastLineEmpty) {
 189                                                 parts.add(new PlainTextPart("\n"));
 190                                         }
 191                                         if (next > 0) {
 192                                                 parts.add(new PlainTextPart(line.substring(0, next)));
 193                                                 line = line.substring(next);
 194                                         }
 195                                         lineComplete = false;
 196
 197                                         int nextSpace = findNextWhitespace(line);
 198                                         String link = line.substring(0, nextSpace);
 199                                         String name = link;
 200                                         logger.log(Level.FINER, String.format("Found link: %s", link));
 201
 202                                         /* if there is no text after the scheme, it’s not a link! */
 203                                         if (link.equals(linkType.getScheme())) {
 204                                                 parts.add(new PlainTextPart(linkType.getScheme()));
 205                                                 line = line.substring(linkType.getScheme().length());
 206                                                 continue;
 207                                         }
 208
 209                                         if (linkType == LinkType.SONE) {
 210                                                 if (line.length() >= (7 + 43)) {
 211                                                         String soneId = line.substring(7, 50);
 212                                                         Optional<Sone> sone = database.getSone(soneId);
 213                                                         if (!sone.isPresent()) {
 214                                                                 /*
 215                                                                  * don’t use create=true above, we don’t want
 216                                                                  * the empty shell.
 217                                                                  */
 218                                                                 sone = Optional.<Sone>of(new DefaultSone(database, soneId, false, null));
 219                                                         }
 220                                                         parts.add(new SonePart(sone.get()));
 221                                                         line = line.substring(50);
 222                                                 } else {
 223                                                         parts.add(new PlainTextPart(line));
 224                                                         line = "";
 225                                                 }
 226                                                 continue;
 227                                         }
 228                                         if (linkType == LinkType.POST) {
 229                                                 if (line.length() >= (7 + 36)) {
 230                                                         String postId = line.substring(7, 43);
 231                                                         Optional<Post> post = database.getPost(postId);
 232                                                         if (post.isPresent()) {
 233                                                                 parts.add(new PostPart(post.get()));
 234                                                         } else {
 235                                                                 parts.add(new PlainTextPart(line.substring(0, 43)));
 236                                                         }
 237                                                         line = line.substring(43);
 238                                                 } else {
 239                                                         parts.add(new PlainTextPart(line));
 240                                                         line = "";
 241                                                 }
 242                                                 continue;
 243                                         }
 244
 245                                         if (linkType.isFreenetLink()) {
 246                                                 FreenetURI uri;
 247                                                 if (name.indexOf('?') > -1) {
 248                                                         name = name.substring(0, name.indexOf('?'));
 249                                                 }
 250                                                 if (name.endsWith("/")) {
 251                                                         name = name.substring(0, name.length() - 1);
 252                                                 }
 253                                                 try {
 254                                                         uri = new FreenetURI(name);
 255                                                         name = uri.lastMetaString();
 256                                                         if (name == null) {
 257                                                                 name = uri.getDocName();
 258                                                         }
 259                                                         if (name == null) {
 260                                                                 name = link.substring(0, Math.min(9, link.length()));
 261                                                         }
 262                                                         boolean fromPostingSone = ((linkType == LinkType.SSK) || (linkType == LinkType.USK)) && (context != null) && (context.getPostingSone() != null) && link.substring(4, Math.min(link.length(), 47)).equals(context.getPostingSone().getId());
 263                                                         parts.add(new FreenetLinkPart(link, name, fromPostingSone));
 264                                                 } catch (MalformedURLException mue1) {
 265                                                         /* not a valid link, insert as plain text. */
 266                                                         parts.add(new PlainTextPart(link));
 267                                                 } catch (NullPointerException npe1) {
 268                                                         /* FreenetURI sometimes throws these, too. */
 269                                                         parts.add(new PlainTextPart(link));
 270                                                 } catch (ArrayIndexOutOfBoundsException aioobe1) {
 271                                                         /* oh, and these, too. */
 272                                                         parts.add(new PlainTextPart(link));
 273                                                 }
 274                                         } else if (linkType.isInternetLink()) {
 275                                                 name = link.substring(linkType.getScheme().length());
 276                                                 int firstSlash = name.indexOf('/');
 277                                                 int lastSlash = name.lastIndexOf('/');
 278                                                 if ((lastSlash - firstSlash) > 3) {
 279                                                         name = name.substring(0, firstSlash + 1) + "…" + name.substring(lastSlash);
 280                                                 }
 281                                                 if (name.endsWith("/")) {
 282                                                         name = name.substring(0, name.length() - 1);
 283                                                 }
 284                                                 if (((name.indexOf('/') > -1) && (name.indexOf('.') < name.lastIndexOf('.', name.indexOf('/'))) || ((name.indexOf('/') == -1) && (name.indexOf('.') < name.lastIndexOf('.')))) && name.startsWith("www.")) {
 285                                                         name = name.substring(4);
 286                                                 }
 287                                                 if (name.indexOf('?') > -1) {
 288                                                         name = name.substring(0, name.indexOf('?'));
 289                                                 }
 290                                                 parts.add(new LinkPart(link, name));
 291                                         }
 292                                         line = line.substring(nextSpace);
 293                                 }
 294                                 lastLineEmpty = false;
 295                         }
 296                 } finally {
 297                         if (bufferedReader != source) {
 298                                 Closer.close(bufferedReader);
 299                         }
 300                 }
 301                 removeTrailingWhitespaceParts(parts);
 302                 return parts;
 303         }
 304
 305         private void removeTrailingWhitespaceParts(PartContainer parts) {
 306                 for (int partIndex = parts.size() - 1; partIndex >= 0; --partIndex) {
 307                         Part part = parts.getPart(partIndex);
 308                         if (!(part instanceof PlainTextPart) || !"\n".equals(part.getText())) {
 309                                 break;
 310                         }
 311                         parts.removePart(partIndex);
 312                 }
 313         }
 314
 315         private int findNextWhitespace(String line) {
 316                 Matcher matcher = whitespacePattern.matcher(line);
 317                 return matcher.find(0) ? matcher.start() : line.length();
 318         }
 319
 320         private Optional<NextLink> findNextLink(String line) {
 321                 EnumMap<LinkType, Integer> linkTypeIndexes = new EnumMap<LinkType, Integer>(LinkType.class);
 322                 for (LinkType linkType : LinkType.values()) {
 323                         int index = line.indexOf(linkType.getScheme());
 324                         if (index != -1) {
 325                                 linkTypeIndexes.put(linkType, index);
 326                         }
 327                 }
 328                 if (linkTypeIndexes.isEmpty()) {
 329                         return absent();
 330                 }
 331                 Entry<LinkType, Integer> smallestEntry = from(linkTypeIndexes.entrySet()).toSortedList(locateSmallestIndex()).get(0);
 332                 return of(new NextLink(smallestEntry.getValue(), smallestEntry.getKey()));
 333         }
 334
 335         private Comparator<Entry<LinkType, Integer>> locateSmallestIndex() {
 336                 return new Comparator<Entry<LinkType, Integer>>() {
 337                         @Override
 338                         public int compare(Entry<LinkType, Integer> leftEntry, Entry<LinkType, Integer> rightEntry) {
 339                                 return leftEntry.getValue() - rightEntry.getValue();
 340                         }
 341                 };
 342         }
 343
 344         /**
 345          * Container for position and type of the next link in a line.
 346          *
 347          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 348          */
 349         private static class NextLink {
 350
 351                 private final int nextIndex;
 352                 private final LinkType linkType;
 353
 354                 private NextLink(int nextIndex, LinkType linkType) {
 355                         this.nextIndex = nextIndex;
 356                         this.linkType = linkType;
 357                 }
 358
 359                 private int getNextIndex() {
 360                         return nextIndex;
 361                 }
 362
 363                 private LinkType getLinkType() {
 364                         return linkType;
 365                 }
 366
 367         }
 368
 369 }