001// License: GPL. For details, see LICENSE file.
002package org.openstreetmap.josm.data.osm;
003
004import static org.openstreetmap.josm.tools.I18n.tr;
005
006import java.awt.geom.Area;
007import java.util.ArrayList;
008import java.util.Collection;
009import java.util.HashMap;
010import java.util.HashSet;
011import java.util.Iterator;
012import java.util.LinkedList;
013import java.util.List;
014import java.util.Map;
015import java.util.Set;
016
017import org.openstreetmap.josm.data.DataSource;
018import org.openstreetmap.josm.data.conflict.Conflict;
019import org.openstreetmap.josm.data.conflict.ConflictCollection;
020import org.openstreetmap.josm.gui.progress.ProgressMonitor;
021import org.openstreetmap.josm.tools.CheckParameterUtil;
022import org.openstreetmap.josm.tools.JosmRuntimeException;
023
024/**
025 * A dataset merger which takes a target and a source dataset and merges the source data set
026 * onto the target dataset.
027 *
028 */
029public class DataSetMerger {
030
031    /** the collection of conflicts created during merging */
032    private final ConflictCollection conflicts;
033
034    /** the target dataset for merging */
035    private final DataSet targetDataSet;
036    /** the source dataset where primitives are merged from */
037    private final DataSet sourceDataSet;
038
039    /**
040     * A map of all primitives that got replaced with other primitives.
041     * Key is the PrimitiveId in their dataset, the value is the PrimitiveId in my dataset
042     */
043    private final Map<PrimitiveId, PrimitiveId> mergedMap;
044    /** a set of primitive ids for which we have to fix references (to nodes and
045     * to relation members) after the first phase of merging
046     */
047    private final Set<PrimitiveId> objectsWithChildrenToMerge;
048    private final Set<OsmPrimitive> objectsToDelete;
049
050    /**
051     * constructor
052     *
053     * The visitor will merge <code>sourceDataSet</code> onto <code>targetDataSet</code>
054     *
055     * @param targetDataSet dataset with my primitives. Must not be null.
056     * @param sourceDataSet dataset with their primitives. Ignored, if null.
057     * @throws IllegalArgumentException if myDataSet is null
058     */
059    public DataSetMerger(DataSet targetDataSet, DataSet sourceDataSet) {
060        CheckParameterUtil.ensureParameterNotNull(targetDataSet, "targetDataSet");
061        this.targetDataSet = targetDataSet;
062        this.sourceDataSet = sourceDataSet;
063        conflicts = new ConflictCollection();
064        mergedMap = new HashMap<>();
065        objectsWithChildrenToMerge = new HashSet<>();
066        objectsToDelete = new HashSet<>();
067    }
068
069    /**
070     * Merges a primitive onto primitives dataset.
071     *
072     * If other.id != 0 it tries to merge it with an corresponding primitive from
073     * my dataset with the same id. If this is not possible a conflict is remembered
074     * in {@link #conflicts}.
075     *
076     * If other.id == 0 (new primitive) it tries to find a primitive in my dataset with id == 0 which
077     * is semantically equal. If it finds one it merges its technical attributes onto
078     * my primitive.
079     *
080     * @param source the primitive to merge
081     * @param candidates a set of possible candidates for a new primitive
082     */
083    protected void mergePrimitive(OsmPrimitive source, Collection<? extends OsmPrimitive> candidates) {
084        if (!source.isNew()) {
085            // try to merge onto a matching primitive with the same defined id
086            //
087            if (mergeById(source))
088                return;
089        } else {
090            // ignore deleted primitives from source
091            if (source.isDeleted()) return;
092
093            // try to merge onto a primitive  which has no id assigned
094            // yet but which is equal in its semantic attributes
095            //
096            for (OsmPrimitive target : candidates) {
097                if (!target.isNew() || target.isDeleted()) {
098                    continue;
099                }
100                if (target.hasEqualSemanticAttributes(source)) {
101                    mergedMap.put(source.getPrimitiveId(), target.getPrimitiveId());
102                    // copy the technical attributes from other version
103                    target.setVisible(source.isVisible());
104                    target.setUser(source.getUser());
105                    target.setRawTimestamp(source.getRawTimestamp());
106                    target.setModified(source.isModified());
107                    objectsWithChildrenToMerge.add(source.getPrimitiveId());
108                    return;
109                }
110            }
111        }
112
113        // If we get here we didn't find a suitable primitive in
114        // the target dataset. Create a clone and add it to the target dataset.
115        //
116        OsmPrimitive target;
117        switch(source.getType()) {
118        case NODE: target = source.isNew() ? new Node() : new Node(source.getId()); break;
119        case WAY: target = source.isNew() ? new Way() : new Way(source.getId()); break;
120        case RELATION: target = source.isNew() ? new Relation() : new Relation(source.getId()); break;
121        default: throw new AssertionError();
122        }
123        target.mergeFrom(source);
124        targetDataSet.addPrimitive(target);
125        mergedMap.put(source.getPrimitiveId(), target.getPrimitiveId());
126        objectsWithChildrenToMerge.add(source.getPrimitiveId());
127    }
128
129    protected OsmPrimitive getMergeTarget(OsmPrimitive mergeSource) {
130        PrimitiveId targetId = mergedMap.get(mergeSource.getPrimitiveId());
131        if (targetId == null)
132            return null;
133        return targetDataSet.getPrimitiveById(targetId);
134    }
135
136    protected void addConflict(Conflict<?> c) {
137        c.setMergedMap(mergedMap);
138        conflicts.add(c);
139    }
140
141    protected void addConflict(OsmPrimitive my, OsmPrimitive their) {
142        addConflict(new Conflict<>(my, their));
143    }
144
145    protected void fixIncomplete(Way other) {
146        Way myWay = (Way) getMergeTarget(other);
147        if (myWay == null)
148            throw new JosmRuntimeException(tr("Missing merge target for way with id {0}", other.getUniqueId()));
149    }
150
151    /**
152     * Postprocess the dataset and fix all merged references to point to the actual
153     * data.
154     */
155    public void fixReferences() {
156        for (Way w : sourceDataSet.getWays()) {
157            if (!conflicts.hasConflictForTheir(w) && objectsWithChildrenToMerge.contains(w.getPrimitiveId())) {
158                mergeNodeList(w);
159                fixIncomplete(w);
160            }
161        }
162        for (Relation r : sourceDataSet.getRelations()) {
163            if (!conflicts.hasConflictForTheir(r) && objectsWithChildrenToMerge.contains(r.getPrimitiveId())) {
164                mergeRelationMembers(r);
165            }
166        }
167
168        deleteMarkedObjects();
169    }
170
171    /**
172     * Deleted objects in objectsToDelete set and create conflicts for objects that cannot
173     * be deleted because they're referenced in the target dataset.
174     */
175    protected void deleteMarkedObjects() {
176        boolean flag;
177        do {
178            flag = false;
179            for (Iterator<OsmPrimitive> it = objectsToDelete.iterator(); it.hasNext();) {
180                OsmPrimitive target = it.next();
181                OsmPrimitive source = sourceDataSet.getPrimitiveById(target.getPrimitiveId());
182                if (source == null)
183                    throw new JosmRuntimeException(
184                            tr("Object of type {0} with id {1} was marked to be deleted, but it''s missing in the source dataset",
185                            target.getType(), target.getUniqueId()));
186
187                List<OsmPrimitive> referrers = target.getReferrers();
188                if (referrers.isEmpty()) {
189                    resetPrimitive(target);
190                    target.mergeFrom(source);
191                    target.setDeleted(true);
192                    it.remove();
193                    flag = true;
194                } else {
195                    for (OsmPrimitive referrer : referrers) {
196                        // If one of object referrers isn't going to be deleted,
197                        // add a conflict and don't delete the object
198                        if (!objectsToDelete.contains(referrer)) {
199                            addConflict(target, source);
200                            it.remove();
201                            flag = true;
202                            break;
203                        }
204                    }
205                }
206
207            }
208        } while (flag);
209
210        if (!objectsToDelete.isEmpty()) {
211            // There are some more objects rest in the objectsToDelete set
212            // This can be because of cross-referenced relations.
213            for (OsmPrimitive osm: objectsToDelete) {
214                resetPrimitive(osm);
215            }
216            for (OsmPrimitive osm: objectsToDelete) {
217                osm.setDeleted(true);
218                osm.mergeFrom(sourceDataSet.getPrimitiveById(osm.getPrimitiveId()));
219            }
220        }
221    }
222
223    private static void resetPrimitive(OsmPrimitive osm) {
224        if (osm instanceof Way) {
225            ((Way) osm).setNodes(null);
226        } else if (osm instanceof Relation) {
227            ((Relation) osm).setMembers(null);
228        }
229    }
230
231    /**
232     * Merges the node list of a source way onto its target way.
233     *
234     * @param source the source way
235     * @throws IllegalStateException if no target way can be found for the source way
236     * @throws IllegalStateException if there isn't a target node for one of the nodes in the source way
237     *
238     */
239    private void mergeNodeList(Way source) {
240        Way target = (Way) getMergeTarget(source);
241        if (target == null)
242            throw new IllegalStateException(tr("Missing merge target for way with id {0}", source.getUniqueId()));
243
244        List<Node> newNodes = new ArrayList<>(source.getNodesCount());
245        for (Node sourceNode : source.getNodes()) {
246            Node targetNode = (Node) getMergeTarget(sourceNode);
247            if (targetNode != null) {
248                newNodes.add(targetNode);
249                if (targetNode.isDeleted() && !conflicts.hasConflictForMy(targetNode)) {
250                    addConflict(new Conflict<OsmPrimitive>(targetNode, sourceNode, true));
251                    targetNode.setDeleted(false);
252                }
253            } else
254                throw new IllegalStateException(tr("Missing merge target for node with id {0}", sourceNode.getUniqueId()));
255        }
256        target.setNodes(newNodes);
257    }
258
259    /**
260     * Merges the relation members of a source relation onto the corresponding target relation.
261     * @param source the source relation
262     * @throws IllegalStateException if there is no corresponding target relation
263     * @throws IllegalStateException if there isn't a corresponding target object for one of the relation
264     * members in source
265     */
266    private void mergeRelationMembers(Relation source) {
267        Relation target = (Relation) getMergeTarget(source);
268        if (target == null)
269            throw new IllegalStateException(tr("Missing merge target for relation with id {0}", source.getUniqueId()));
270        List<RelationMember> newMembers = new LinkedList<>();
271        for (RelationMember sourceMember : source.getMembers()) {
272            OsmPrimitive targetMember = getMergeTarget(sourceMember.getMember());
273            if (targetMember == null)
274                throw new IllegalStateException(tr("Missing merge target of type {0} with id {1}",
275                        sourceMember.getType(), sourceMember.getUniqueId()));
276            RelationMember newMember = new RelationMember(sourceMember.getRole(), targetMember);
277            newMembers.add(newMember);
278            if (targetMember.isDeleted() && !conflicts.hasConflictForMy(targetMember)) {
279                addConflict(new Conflict<>(targetMember, sourceMember.getMember(), true));
280                targetMember.setDeleted(false);
281            }
282        }
283        target.setMembers(newMembers);
284    }
285
286    /**
287     * Tries to merge a primitive <code>source</code> into an existing primitive with the same id.
288     *
289     * @param source  the source primitive which is to be merged into a target primitive
290     * @return true, if this method was able to merge <code>source</code> into a target object; false, otherwise
291     */
292    private boolean mergeById(OsmPrimitive source) {
293        OsmPrimitive target = targetDataSet.getPrimitiveById(source.getId(), source.getType());
294        // merge other into an existing primitive with the same id, if possible
295        //
296        if (target == null)
297            return false;
298        // found a corresponding target, remember it
299        mergedMap.put(source.getPrimitiveId(), target.getPrimitiveId());
300
301        if (target.getVersion() > source.getVersion())
302            // target.version > source.version => keep target version
303            return true;
304
305        if (target.isIncomplete() && !source.isIncomplete()) {
306            // target is incomplete, source completes it
307            // => merge source into target
308            //
309            target.mergeFrom(source);
310            objectsWithChildrenToMerge.add(source.getPrimitiveId());
311        } else if (!target.isIncomplete() && source.isIncomplete()) {
312            // target is complete and source is incomplete
313            // => keep target, it has more information already
314            //
315        } else if (target.isIncomplete() && source.isIncomplete()) {
316            // target and source are incomplete. Doesn't matter which one to
317            // take. We take target.
318            //
319        } else if (!target.isModified() && !source.isModified() && target.isVisible() != source.isVisible()
320                && target.getVersion() == source.getVersion()) {
321            // Same version, but different "visible" attribute and neither of them are modified.
322            // It indicates a serious problem in datasets.
323            // For example, datasets can be fetched from different OSM servers or badly hand-modified.
324            // We shouldn't merge that datasets.
325            throw new DataIntegrityProblemException(tr("Conflict in ''visible'' attribute for object of type {0} with id {1}",
326                    target.getType(), target.getId()));
327        } else if (target.isDeleted() && !source.isDeleted() && target.getVersion() == source.getVersion()) {
328            // same version, but target is deleted. Assume target takes precedence
329            // otherwise too many conflicts when refreshing from the server
330            // but, if source is modified, there is a conflict
331            if (source.isModified()) {
332                addConflict(new Conflict<>(target, source, true));
333            }
334            // or, if source has a referrer that is not in the target dataset there is a conflict
335            // If target dataset refers to the deleted primitive, conflict will be added in fixReferences method
336            for (OsmPrimitive referrer: source.getReferrers()) {
337                if (targetDataSet.getPrimitiveById(referrer.getPrimitiveId()) == null) {
338                    addConflict(new Conflict<>(target, source, true));
339                    target.setDeleted(false);
340                    break;
341                }
342            }
343        } else if (!target.isModified() && source.isDeleted()) {
344            // target not modified. We can assume that source is the most recent version,
345            // so mark it to be deleted.
346            //
347            objectsToDelete.add(target);
348        } else if (!target.isModified() && source.isModified()) {
349            // target not modified. We can assume that source is the most recent version.
350            // clone it into target.
351            target.mergeFrom(source);
352            objectsWithChildrenToMerge.add(source.getPrimitiveId());
353        } else if (!target.isModified() && !source.isModified() && target.getVersion() == source.getVersion()) {
354            // both not modified. Merge nevertheless.
355            // This helps when updating "empty" relations, see #4295
356            target.mergeFrom(source);
357            objectsWithChildrenToMerge.add(source.getPrimitiveId());
358        } else if (!target.isModified() && !source.isModified() && target.getVersion() < source.getVersion()) {
359            // my not modified but other is newer. clone other onto mine.
360            //
361            target.mergeFrom(source);
362            objectsWithChildrenToMerge.add(source.getPrimitiveId());
363        } else if (target.isModified() && !source.isModified() && target.getVersion() == source.getVersion()) {
364            // target is same as source but target is modified
365            // => keep target and reset modified flag if target and source are semantically equal
366            if (target.hasEqualSemanticAttributes(source, false)) {
367                target.setModified(false);
368            }
369        } else if (source.isDeleted() != target.isDeleted()) {
370            // target is modified and deleted state differs.
371            // this have to be resolved manually.
372            //
373            addConflict(target, source);
374        } else if (!target.hasEqualSemanticAttributes(source)) {
375            // target is modified and is not semantically equal with source. Can't automatically
376            // resolve the differences
377            // =>  create a conflict
378            addConflict(target, source);
379        } else {
380            // clone from other. mergeFrom will mainly copy
381            // technical attributes like timestamp or user information. Semantic
382            // attributes should already be equal if we get here.
383            //
384            target.mergeFrom(source);
385            objectsWithChildrenToMerge.add(source.getPrimitiveId());
386        }
387        return true;
388    }
389
390    /**
391     * Runs the merge operation. Successfully merged {@link OsmPrimitive}s are in
392     * {@link #getTargetDataSet()}.
393     *
394     * See {@link #getConflicts()} for a map of conflicts after the merge operation.
395     */
396    public void merge() {
397        merge(null);
398    }
399
400    /**
401     * Runs the merge operation. Successfully merged {@link OsmPrimitive}s are in
402     * {@link #getTargetDataSet()}.
403     *
404     * See {@link #getConflicts()} for a map of conflicts after the merge operation.
405     * @param progressMonitor The progress monitor
406     */
407    public void merge(ProgressMonitor progressMonitor) {
408        if (sourceDataSet == null)
409            return;
410        if (progressMonitor != null) {
411            progressMonitor.beginTask(tr("Merging data..."), sourceDataSet.allPrimitives().size());
412        }
413        targetDataSet.beginUpdate();
414        try {
415            List<? extends OsmPrimitive> candidates = new ArrayList<>(targetDataSet.getNodes());
416            for (Node node: sourceDataSet.getNodes()) {
417                mergePrimitive(node, candidates);
418                if (progressMonitor != null) {
419                    progressMonitor.worked(1);
420                }
421            }
422            candidates.clear();
423            candidates = new ArrayList<>(targetDataSet.getWays());
424            for (Way way: sourceDataSet.getWays()) {
425                mergePrimitive(way, candidates);
426                if (progressMonitor != null) {
427                    progressMonitor.worked(1);
428                }
429            }
430            candidates.clear();
431            candidates = new ArrayList<>(targetDataSet.getRelations());
432            for (Relation relation: sourceDataSet.getRelations()) {
433                mergePrimitive(relation, candidates);
434                if (progressMonitor != null) {
435                    progressMonitor.worked(1);
436                }
437            }
438            candidates.clear();
439            fixReferences();
440
441            Area a = targetDataSet.getDataSourceArea();
442
443            // copy the merged layer's data source info.
444            // only add source rectangles if they are not contained in the layer already.
445            for (DataSource src : sourceDataSet.getDataSources()) {
446                if (a == null || !a.contains(src.bounds.asRect())) {
447                    targetDataSet.addDataSource(src);
448                }
449            }
450
451            // copy the merged layer's API version
452            if (targetDataSet.getVersion() == null) {
453                targetDataSet.setVersion(sourceDataSet.getVersion());
454            }
455
456            // copy the merged layer's policies and locked status
457            if (sourceDataSet.getUploadPolicy() != null && (targetDataSet.getUploadPolicy() == null
458                    || sourceDataSet.getUploadPolicy().compareTo(targetDataSet.getUploadPolicy()) > 0)) {
459                targetDataSet.setUploadPolicy(sourceDataSet.getUploadPolicy());
460            }
461            if (sourceDataSet.getDownloadPolicy() != null && (targetDataSet.getDownloadPolicy() == null
462                    || sourceDataSet.getDownloadPolicy().compareTo(targetDataSet.getDownloadPolicy()) > 0)) {
463                targetDataSet.setDownloadPolicy(sourceDataSet.getDownloadPolicy());
464            }
465            if (sourceDataSet.isLocked() && !targetDataSet.isLocked()) {
466                targetDataSet.lock();
467            }
468        } finally {
469            targetDataSet.endUpdate();
470        }
471        if (progressMonitor != null) {
472            progressMonitor.finishTask();
473        }
474    }
475
476    /**
477     * replies my dataset
478     *
479     * @return the own (target) data set
480     */
481    public DataSet getTargetDataSet() {
482        return targetDataSet;
483    }
484
485    /**
486     * replies the map of conflicts
487     *
488     * @return the map of conflicts
489     */
490    public ConflictCollection getConflicts() {
491        return conflicts;
492    }
493}