source: josm/trunk/src/org/openstreetmap/josm/io/MultiFetchServerObjectReader.java@ 10300

Last change on this file since 10300 was 10217, checked in by Don-vip, 8 years ago

findbugs - SF_SWITCH_NO_DEFAULT + various sonar fixes
  • Property svn:eol-style set to native
File size: 24.7 KB
Line 
1// License: GPL. For details, see LICENSE file.
2package org.openstreetmap.josm.io;
3
4import static org.openstreetmap.josm.tools.I18n.tr;
5import static org.openstreetmap.josm.tools.I18n.trn;
6
7import java.io.IOException;
8import java.io.InputStream;
9import java.net.HttpURLConnection;
10import java.util.ArrayList;
11import java.util.Collection;
12import java.util.Collections;
13import java.util.HashSet;
14import java.util.Iterator;
15import java.util.LinkedHashSet;
16import java.util.List;
17import java.util.Set;
18import java.util.concurrent.Callable;
19import java.util.concurrent.CompletionService;
20import java.util.concurrent.ExecutionException;
21import java.util.concurrent.ExecutorCompletionService;
22import java.util.concurrent.ExecutorService;
23import java.util.concurrent.Executors;
24import java.util.concurrent.Future;
25
26import org.openstreetmap.josm.Main;
27import org.openstreetmap.josm.data.osm.DataSet;
28import org.openstreetmap.josm.data.osm.DataSetMerger;
29import org.openstreetmap.josm.data.osm.Node;
30import org.openstreetmap.josm.data.osm.OsmPrimitive;
31import org.openstreetmap.josm.data.osm.OsmPrimitiveType;
32import org.openstreetmap.josm.data.osm.PrimitiveId;
33import org.openstreetmap.josm.data.osm.Relation;
34import org.openstreetmap.josm.data.osm.RelationMember;
35import org.openstreetmap.josm.data.osm.SimplePrimitiveId;
36import org.openstreetmap.josm.data.osm.Way;
37import org.openstreetmap.josm.gui.preferences.server.OverpassServerPreference;
38import org.openstreetmap.josm.gui.progress.NullProgressMonitor;
39import org.openstreetmap.josm.gui.progress.ProgressMonitor;
40import org.openstreetmap.josm.tools.Utils;
41
42/**
43 * Retrieves a set of {@link OsmPrimitive}s from an OSM server using the so called
44 * Multi Fetch API.
45 *
46 * Usage:
47 * <pre>
48 * MultiFetchServerObjectReader reader = MultiFetchServerObjectReader()
49 * .append(2345,2334,4444)
50 * .append(new Node(72343));
51 * reader.parseOsm();
52 * if (!reader.getMissingPrimitives().isEmpty()) {
53 * Main.info("There are missing primitives: " + reader.getMissingPrimitives());
54 * }
55 * if (!reader.getSkippedWays().isEmpty()) {
56 * Main.info("There are skipped ways: " + reader.getMissingPrimitives());
57 * }
58 * </pre>
59 */
60public class MultiFetchServerObjectReader extends OsmServerReader {
61 /**
62 * the max. number of primitives retrieved in one step. Assuming IDs with 7 digits,
63 * this leads to a max. request URL of ~ 1600 Bytes ((7 digits + 1 Separator) * 200),
64 * which should be safe according to the
65 * <a href="http://www.boutell.com/newfaq/misc/urllength.html">WWW FAQ</a>.
66 */
67 private static final int MAX_IDS_PER_REQUEST = 200;
68
69 private final Set<Long> nodes;
70 private final Set<Long> ways;
71 private final Set<Long> relations;
72 private Set<PrimitiveId> missingPrimitives;
73 private final DataSet outputDataSet;
74
75 /**
76 * Constructs a {@code MultiFetchServerObjectReader}.
77 */
78 protected MultiFetchServerObjectReader() {
79 nodes = new LinkedHashSet<>();
80 ways = new LinkedHashSet<>();
81 relations = new LinkedHashSet<>();
82 this.outputDataSet = new DataSet();
83 this.missingPrimitives = new LinkedHashSet<>();
84 }
85
86 /**
87 * Creates a new instance of {@link MultiFetchServerObjectReader} or {@link MultiFetchOverpassObjectReader}
88 * depending on the {@link OverpassServerPreference#useForMultiFetch preference}.
89 *
90 * @return a new instance
91 * @since 9241
92 */
93 public static MultiFetchServerObjectReader create() {
94 return create(OverpassServerPreference.useForMultiFetch());
95 }
96
97 /**
98 * Creates a new instance of {@link MultiFetchServerObjectReader} or {@link MultiFetchOverpassObjectReader}
99 * depending on the {@code fromMirror} parameter.
100 *
101 * @param fromMirror {@code false} for {@link MultiFetchServerObjectReader}, {@code true} for {@link MultiFetchOverpassObjectReader}
102 * @return a new instance
103 * @since 9241
104 */
105 static MultiFetchServerObjectReader create(final boolean fromMirror) {
106 if (fromMirror) {
107 return new MultiFetchOverpassObjectReader();
108 } else {
109 return new MultiFetchServerObjectReader();
110 }
111 }
112
113 /**
114 * Remembers an {@link OsmPrimitive}'s id. The id will
115 * later be fetched as part of a Multi Get request.
116 *
117 * Ignore the id if it represents a new primitives.
118 *
119 * @param id the id
120 */
121 protected void remember(PrimitiveId id) {
122 if (id.isNew()) return;
123 switch(id.getType()) {
124 case NODE: nodes.add(id.getUniqueId()); break;
125 case WAY: ways.add(id.getUniqueId()); break;
126 case RELATION: relations.add(id.getUniqueId()); break;
127 default: throw new AssertionError();
128 }
129 }
130
131 /**
132 * appends a {@link OsmPrimitive} id to the list of ids which will be fetched from the server.
133 *
134 * @param ds the {@link DataSet} to which the primitive belongs
135 * @param id the primitive id
136 * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
137 * {@link OsmPrimitiveType#RELATION RELATION}
138 * @return this
139 */
140 public MultiFetchServerObjectReader append(DataSet ds, long id, OsmPrimitiveType type) {
141 OsmPrimitive p = ds.getPrimitiveById(id, type);
142 switch(type) {
143 case NODE:
144 return appendNode((Node) p);
145 case WAY:
146 return appendWay((Way) p);
147 case RELATION:
148 return appendRelation((Relation) p);
149 }
150 return this;
151 }
152
153 /**
154 * appends a {@link Node} id to the list of ids which will be fetched from the server.
155 *
156 * @param node the node (ignored, if null)
157 * @return this
158 */
159 public MultiFetchServerObjectReader appendNode(Node node) {
160 if (node == null) return this;
161 remember(node.getPrimitiveId());
162 return this;
163 }
164
165 /**
166 * appends a {@link Way} id and the list of ids of nodes the way refers to the list of ids which will be fetched from the server.
167 *
168 * @param way the way (ignored, if null)
169 * @return this
170 */
171 public MultiFetchServerObjectReader appendWay(Way way) {
172 if (way == null) return this;
173 if (way.isNew()) return this;
174 for (Node node: !recursesDown() ? way.getNodes() : Collections.<Node>emptyList()) {
175 if (!node.isNew()) {
176 remember(node.getPrimitiveId());
177 }
178 }
179 remember(way.getPrimitiveId());
180 return this;
181 }
182
183 /**
184 * appends a {@link Relation} id to the list of ids which will be fetched from the server.
185 *
186 * @param relation the relation (ignored, if null)
187 * @return this
188 */
189 protected MultiFetchServerObjectReader appendRelation(Relation relation) {
190 if (relation == null) return this;
191 if (relation.isNew()) return this;
192 remember(relation.getPrimitiveId());
193 for (RelationMember member : !recursesDown() ? relation.getMembers() : Collections.<RelationMember>emptyList()) {
194 if (OsmPrimitiveType.from(member.getMember()).equals(OsmPrimitiveType.RELATION)) {
195 // avoid infinite recursion in case of cyclic dependencies in relations
196 //
197 if (relations.contains(member.getMember().getId())) {
198 continue;
199 }
200 }
201 if (!member.getMember().isIncomplete()) {
202 append(member.getMember());
203 }
204 }
205 return this;
206 }
207
208 /**
209 * appends an {@link OsmPrimitive} to the list of ids which will be fetched from the server.
210 * @param primitive the primitive
211 * @return this
212 */
213 public MultiFetchServerObjectReader append(OsmPrimitive primitive) {
214 if (primitive != null) {
215 switch (OsmPrimitiveType.from(primitive)) {
216 case NODE: return appendNode((Node) primitive);
217 case WAY: return appendWay((Way) primitive);
218 case RELATION: return appendRelation((Relation) primitive);
219 }
220 }
221 return this;
222 }
223
224 /**
225 * appends a list of {@link OsmPrimitive} to the list of ids which will be fetched from the server.
226 *
227 * @param primitives the list of primitives (ignored, if null)
228 * @return this
229 *
230 * @see #append(OsmPrimitive)
231 */
232 public MultiFetchServerObjectReader append(Collection<? extends OsmPrimitive> primitives) {
233 if (primitives == null) return this;
234 for (OsmPrimitive primitive : primitives) {
235 append(primitive);
236 }
237 return this;
238 }
239
240 /**
241 * extracts a subset of max {@link #MAX_IDS_PER_REQUEST} ids from <code>ids</code> and
242 * replies the subset. The extracted subset is removed from <code>ids</code>.
243 *
244 * @param ids a set of ids
245 * @return the subset of ids
246 */
247 protected Set<Long> extractIdPackage(Set<Long> ids) {
248 Set<Long> pkg = new HashSet<>();
249 if (ids.isEmpty())
250 return pkg;
251 if (ids.size() > MAX_IDS_PER_REQUEST) {
252 Iterator<Long> it = ids.iterator();
253 for (int i = 0; i < MAX_IDS_PER_REQUEST; i++) {
254 pkg.add(it.next());
255 }
256 ids.removeAll(pkg);
257 } else {
258 pkg.addAll(ids);
259 ids.clear();
260 }
261 return pkg;
262 }
263
264 /**
265 * builds the Multi Get request string for a set of ids and a given {@link OsmPrimitiveType}.
266 *
267 * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
268 * {@link OsmPrimitiveType#RELATION RELATION}
269 * @param idPackage the package of ids
270 * @return the request string
271 */
272 protected String buildRequestString(final OsmPrimitiveType type, Set<Long> idPackage) {
273 return type.getAPIName() + "s?" + type.getAPIName() + "s=" + Utils.join(",", idPackage);
274 }
275
276 @Override
277 protected String getBaseUrl() {
278 return super.getBaseUrl();
279 }
280
281 protected void rememberNodesOfIncompleteWaysToLoad(DataSet from) {
282 for (Way w: from.getWays()) {
283 if (w.hasIncompleteNodes()) {
284 for (Node n: w.getNodes()) {
285 if (n.isIncomplete()) {
286 nodes.add(n.getId());
287 }
288 }
289 }
290 }
291 }
292
293 /**
294 * merges the dataset <code>from</code> to {@link #outputDataSet}.
295 *
296 * @param from the other dataset
297 */
298 protected void merge(DataSet from) {
299 final DataSetMerger visitor = new DataSetMerger(outputDataSet, from);
300 visitor.merge();
301 }
302
303 /**
304 * fetches a set of ids of a given {@link OsmPrimitiveType} from the server
305 *
306 * @param ids the set of ids
307 * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
308 * {@link OsmPrimitiveType#RELATION RELATION}
309 * @param progressMonitor progress monitor
310 * @throws OsmTransferException if an error occurs while communicating with the API server
311 */
312 protected void fetchPrimitives(Set<Long> ids, OsmPrimitiveType type, ProgressMonitor progressMonitor) throws OsmTransferException {
313 String msg;
314 final String baseUrl = getBaseUrl();
315 switch (type) {
316 case NODE: msg = tr("Fetching a package of nodes from ''{0}''", baseUrl); break;
317 case WAY: msg = tr("Fetching a package of ways from ''{0}''", baseUrl); break;
318 case RELATION: msg = tr("Fetching a package of relations from ''{0}''", baseUrl); break;
319 default: throw new AssertionError();
320 }
321 progressMonitor.setTicksCount(ids.size());
322 progressMonitor.setTicks(0);
323 // The complete set containing all primitives to fetch
324 Set<Long> toFetch = new HashSet<>(ids);
325 // Build a list of fetchers that will download smaller sets containing only MAX_IDS_PER_REQUEST (200) primitives each.
326 // we will run up to MAX_DOWNLOAD_THREADS concurrent fetchers.
327 int threadsNumber = Main.pref.getInteger("osm.download.threads", OsmApi.MAX_DOWNLOAD_THREADS);
328 threadsNumber = Math.min(Math.max(threadsNumber, 1), OsmApi.MAX_DOWNLOAD_THREADS);
329 final ExecutorService exec = Executors.newFixedThreadPool(
330 threadsNumber, Utils.newThreadFactory(getClass() + "-%d", Thread.NORM_PRIORITY));
331 CompletionService<FetchResult> ecs = new ExecutorCompletionService<>(exec);
332 List<Future<FetchResult>> jobs = new ArrayList<>();
333 while (!toFetch.isEmpty()) {
334 jobs.add(ecs.submit(new Fetcher(type, extractIdPackage(toFetch), progressMonitor)));
335 }
336 // Run the fetchers
337 for (int i = 0; i < jobs.size() && !isCanceled(); i++) {
338 progressMonitor.subTask(msg + "... " + progressMonitor.getTicks() + '/' + progressMonitor.getTicksCount());
339 try {
340 FetchResult result = ecs.take().get();
341 if (result.missingPrimitives != null) {
342 missingPrimitives.addAll(result.missingPrimitives);
343 }
344 if (result.dataSet != null && !isCanceled()) {
345 rememberNodesOfIncompleteWaysToLoad(result.dataSet);
346 merge(result.dataSet);
347 }
348 } catch (InterruptedException | ExecutionException e) {
349 Main.error(e);
350 }
351 }
352 exec.shutdown();
353 // Cancel requests if the user chose to
354 if (isCanceled()) {
355 for (Future<FetchResult> job : jobs) {
356 job.cancel(true);
357 }
358 }
359 }
360
361 /**
362 * invokes one or more Multi Gets to fetch the {@link OsmPrimitive}s and replies
363 * the dataset of retrieved primitives. Note that the dataset includes non visible primitives too!
364 * In contrast to a simple Get for a node, a way, or a relation, a Multi Get always replies
365 * the latest version of the primitive (if any), even if the primitive is not visible (i.e. if
366 * visible==false).
367 *
368 * Invoke {@link #getMissingPrimitives()} to get a list of primitives which have not been
369 * found on the server (the server response code was 404)
370 *
371 * @return the parsed data
372 * @throws OsmTransferException if an error occurs while communicating with the API server
373 * @see #getMissingPrimitives()
374 *
375 */
376 @Override
377 public DataSet parseOsm(ProgressMonitor progressMonitor) throws OsmTransferException {
378 int n = nodes.size() + ways.size() + relations.size();
379 progressMonitor.beginTask(trn("Downloading {0} object from ''{1}''",
380 "Downloading {0} objects from ''{1}''", n, n, OsmApi.getOsmApi().getBaseUrl()));
381 try {
382 missingPrimitives = new HashSet<>();
383 if (isCanceled()) return null;
384 fetchPrimitives(ways, OsmPrimitiveType.WAY, progressMonitor);
385 if (isCanceled()) return null;
386 fetchPrimitives(nodes, OsmPrimitiveType.NODE, progressMonitor);
387 if (isCanceled()) return null;
388 fetchPrimitives(relations, OsmPrimitiveType.RELATION, progressMonitor);
389 if (outputDataSet != null) {
390 outputDataSet.deleteInvisible();
391 }
392 return outputDataSet;
393 } finally {
394 progressMonitor.finishTask();
395 }
396 }
397
398 /**
399 * replies the set of ids of all primitives for which a fetch request to the
400 * server was submitted but which are not available from the server (the server
401 * replied a return code of 404)
402 *
403 * @return the set of ids of missing primitives
404 */
405 public Set<PrimitiveId> getMissingPrimitives() {
406 return missingPrimitives;
407 }
408
409 /**
410 * Whether this reader fetches nodes when loading ways, or members when loading relations.
411 *
412 * @return {@code true} if the reader recurses down
413 */
414 protected boolean recursesDown() {
415 return false;
416 }
417
418 /**
419 * The class holding the results given by {@link Fetcher}.
420 * It is only a wrapper of the resulting {@link DataSet} and the collection of {@link PrimitiveId} that could not have been loaded.
421 */
422 protected static class FetchResult {
423
424 /**
425 * The resulting data set
426 */
427 public final DataSet dataSet;
428
429 /**
430 * The collection of primitive ids that could not have been loaded
431 */
432 public final Set<PrimitiveId> missingPrimitives;
433
434 /**
435 * Constructs a {@code FetchResult}
436 * @param dataSet The resulting data set
437 * @param missingPrimitives The collection of primitive ids that could not have been loaded
438 */
439 public FetchResult(DataSet dataSet, Set<PrimitiveId> missingPrimitives) {
440 this.dataSet = dataSet;
441 this.missingPrimitives = missingPrimitives;
442 }
443 }
444
445 /**
446 * The class that actually download data from OSM API.
447 * Several instances of this class are used by {@link MultiFetchServerObjectReader} (one per set of primitives to fetch).
448 * The inheritance of {@link OsmServerReader} is only explained by the need to have a distinct OSM connection by {@code Fetcher} instance.
449 * @see FetchResult
450 */
451 protected class Fetcher extends OsmServerReader implements Callable<FetchResult> {
452
453 private final Set<Long> pkg;
454 private final OsmPrimitiveType type;
455 private final ProgressMonitor progressMonitor;
456
457 /**
458 * Constructs a {@code Fetcher}
459 * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
460 * {@link OsmPrimitiveType#RELATION RELATION}
461 * @param idsPackage The set of primitives ids to fetch
462 * @param progressMonitor The progress monitor
463 */
464 public Fetcher(OsmPrimitiveType type, Set<Long> idsPackage, ProgressMonitor progressMonitor) {
465 this.pkg = idsPackage;
466 this.type = type;
467 this.progressMonitor = progressMonitor;
468 }
469
470 @Override
471 public DataSet parseOsm(ProgressMonitor progressMonitor) throws OsmTransferException {
472 // This method is implemented because of the OsmServerReader inheritance, but not used,
473 // as the main target of this class is the call() method.
474 return fetch(progressMonitor).dataSet;
475 }
476
477 @Override
478 public FetchResult call() throws Exception {
479 return fetch(progressMonitor);
480 }
481
482 /**
483 * fetches the requested primitives and updates the specified progress monitor.
484 * @param progressMonitor the progress monitor
485 * @return the {@link FetchResult} of this operation
486 * @throws OsmTransferException if an error occurs while communicating with the API server
487 */
488 protected FetchResult fetch(ProgressMonitor progressMonitor) throws OsmTransferException {
489 try {
490 return multiGetIdPackage(type, pkg, progressMonitor);
491 } catch (OsmApiException e) {
492 if (e.getResponseCode() == HttpURLConnection.HTTP_NOT_FOUND) {
493 Main.info(tr("Server replied with response code 404, retrying with an individual request for each object."));
494 return singleGetIdPackage(type, pkg, progressMonitor);
495 } else {
496 throw e;
497 }
498 }
499 }
500
501 @Override
502 protected String getBaseUrl() {
503 return MultiFetchServerObjectReader.this.getBaseUrl();
504 }
505
506 /**
507 * invokes a Multi Get for a set of ids and a given {@link OsmPrimitiveType}.
508 * The retrieved primitives are merged to {@link #outputDataSet}.
509 *
510 * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
511 * {@link OsmPrimitiveType#RELATION RELATION}
512 * @param pkg the package of ids
513 * @param progressMonitor progress monitor
514 * @return the {@link FetchResult} of this operation
515 * @throws OsmTransferException if an error occurs while communicating with the API server
516 */
517 protected FetchResult multiGetIdPackage(OsmPrimitiveType type, Set<Long> pkg, ProgressMonitor progressMonitor)
518 throws OsmTransferException {
519 String request = buildRequestString(type, pkg);
520 FetchResult result = null;
521 try (InputStream in = getInputStream(request, NullProgressMonitor.INSTANCE)) {
522 if (in == null) return null;
523 progressMonitor.subTask(tr("Downloading OSM data..."));
524 try {
525 result = new FetchResult(OsmReader.parseDataSet(in, progressMonitor.createSubTaskMonitor(pkg.size(), false)), null);
526 } catch (IllegalDataException e) {
527 throw new OsmTransferException(e);
528 }
529 } catch (IOException ex) {
530 Main.warn(ex);
531 }
532 return result;
533 }
534
535 /**
536 * invokes a Multi Get for a single id and a given {@link OsmPrimitiveType}.
537 * The retrieved primitive is merged to {@link #outputDataSet}.
538 *
539 * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
540 * {@link OsmPrimitiveType#RELATION RELATION}
541 * @param id the id
542 * @param progressMonitor progress monitor
543 * @return the {@link DataSet} resulting of this operation
544 * @throws OsmTransferException if an error occurs while communicating with the API server
545 */
546 protected DataSet singleGetId(OsmPrimitiveType type, long id, ProgressMonitor progressMonitor) throws OsmTransferException {
547 String request = buildRequestString(type, Collections.singleton(id));
548 DataSet result = null;
549 try (InputStream in = getInputStream(request, NullProgressMonitor.INSTANCE)) {
550 if (in == null) return null;
551 progressMonitor.subTask(tr("Downloading OSM data..."));
552 try {
553 result = OsmReader.parseDataSet(in, progressMonitor.createSubTaskMonitor(1, false));
554 } catch (IllegalDataException e) {
555 throw new OsmTransferException(e);
556 }
557 } catch (IOException ex) {
558 Main.warn(ex);
559 }
560 return result;
561 }
562
563 /**
564 * invokes a sequence of Multi Gets for individual ids in a set of ids and a given {@link OsmPrimitiveType}.
565 * The retrieved primitives are merged to {@link #outputDataSet}.
566 *
567 * This method is used if one of the ids in pkg doesn't exist (the server replies with return code 404).
568 * If the set is fetched with this method it is possible to find out which of the ids doesn't exist.
569 * Unfortunately, the server does not provide an error header or an error body for a 404 reply.
570 *
571 * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY},
572 * {@link OsmPrimitiveType#RELATION RELATION}
573 * @param pkg the set of ids
574 * @param progressMonitor progress monitor
575 * @return the {@link FetchResult} of this operation
576 * @throws OsmTransferException if an error occurs while communicating with the API server
577 */
578 protected FetchResult singleGetIdPackage(OsmPrimitiveType type, Set<Long> pkg, ProgressMonitor progressMonitor)
579 throws OsmTransferException {
580 FetchResult result = new FetchResult(new DataSet(), new HashSet<PrimitiveId>());
581 String baseUrl = OsmApi.getOsmApi().getBaseUrl();
582 for (long id : pkg) {
583 try {
584 String msg;
585 switch (type) {
586 case NODE: msg = tr("Fetching node with id {0} from ''{1}''", id, baseUrl); break;
587 case WAY: msg = tr("Fetching way with id {0} from ''{1}''", id, baseUrl); break;
588 case RELATION: msg = tr("Fetching relation with id {0} from ''{1}''", id, baseUrl); break;
589 default: throw new AssertionError();
590 }
591 progressMonitor.setCustomText(msg);
592 result.dataSet.mergeFrom(singleGetId(type, id, progressMonitor));
593 } catch (OsmApiException e) {
594 if (e.getResponseCode() == HttpURLConnection.HTTP_NOT_FOUND) {
595 Main.info(tr("Server replied with response code 404 for id {0}. Skipping.", Long.toString(id)));
596 result.missingPrimitives.add(new SimplePrimitiveId(id, type));
597 } else {
598 throw e;
599 }
600 }
601 }
602 return result;
603 }
604 }
605}
Note: See TracBrowser for help on using the repository browser.