001// License: GPL. For details, see LICENSE file.
002package org.openstreetmap.josm.data.osm;
003
004import java.util.ArrayList;
005import java.util.Collection;
006import java.util.List;
007
008import org.openstreetmap.josm.data.osm.search.SearchCompiler;
009import org.openstreetmap.josm.data.osm.search.SearchCompiler.Match;
010import org.openstreetmap.josm.data.osm.search.SearchCompiler.Not;
011import org.openstreetmap.josm.data.osm.search.SearchMode;
012import org.openstreetmap.josm.data.osm.search.SearchParseError;
013import org.openstreetmap.josm.tools.SubclassFilteredCollection;
014
015/**
016 * Class that encapsulates the filter logic, i.e. applies a list of
017 * filters to a primitive.
018 *
019 * Uses {@link Match#match} to see if the filter expression matches,
020 * cares for "inverted-flag" of the filters and combines the results of all active
021 * filters.
022 *
023 * There are two major use cases:
024 *
025 * (1) Hide features that you don't like to edit but get in the way, e.g.
026 * <code>landuse</code> or power lines. It is expected, that the inverted flag
027 * if false for these kind of filters.
028 *
029 * (2) Highlight certain features, that are currently interesting and hide everything
030 * else. This can be thought of as an improved search (Ctrl-F), where you can
031 * continue editing and don't loose the current selection. It is expected that
032 * the inverted flag of the filter is true in this case.
033 *
034 * In addition to the formal application of filter rules, some magic is applied
035 * to (hopefully) match the expectations of the user:
036 *
037 * (1) non-inverted: When hiding a way, all its untagged nodes are hidden as well.
038 * This avoids a "cloud of nodes", that normally isn't useful without the
039 * corresponding way.
040 *
041 * (2) inverted: When displaying a way, we show all its nodes, although the
042 * individual nodes do not match the filter expression. The reason is, that a
043 * way without its nodes cannot be edited properly.
044 *
045 * Multipolygons and (untagged) member ways are handled in a similar way.
046 */
047public class FilterMatcher {
048
049    /**
050     * Describes quality of the filtering.
051     *
052     * Depending on the context, this can either refer to disabled or
053     * to hidden primitives.
054     *
055     * The distinction is necessary, because untagged nodes should only
056     * "inherit" their filter property from the parent way, when the
057     * parent way is hidden (or disabled) "explicitly" (i.e. by a non-inverted
058     * filter). This way, filters like
059     * <code>["child type:way", inverted, Add]</code> show the
060     * untagged way nodes, as intended.
061     *
062     * This information is only needed for ways and relations, so nodes are
063     * either <code>NOT_FILTERED</code> or <code>PASSIV</code>.
064     */
065    public enum FilterType {
066        /** no filter applies */
067        NOT_FILTERED,
068        /** at least one non-inverted filter applies */
069        EXPLICIT,
070        /** at least one filter applies, but they are all inverted filters */
071        PASSIV
072    }
073
074    private static class FilterInfo {
075        private final Match match;
076        private final boolean isDelete;
077        private final boolean isInverted;
078
079        FilterInfo(Filter filter) throws SearchParseError {
080            if (filter.mode == SearchMode.remove || filter.mode == SearchMode.in_selection) {
081                isDelete = true;
082            } else {
083                isDelete = false;
084            }
085
086            Match compiled = SearchCompiler.compile(filter);
087            this.match = filter.inverted ? new Not(compiled) : compiled;
088            this.isInverted = filter.inverted;
089        }
090    }
091
092    private final List<FilterInfo> hiddenFilters = new ArrayList<>();
093    private final List<FilterInfo> disabledFilters = new ArrayList<>();
094
095    /**
096     * Clears the current filters, and adds the given filters
097     * @param filters the filters to add
098     * @throws SearchParseError if the search expression in one of the filters cannot be parsed
099     */
100    public void update(Collection<Filter> filters) throws SearchParseError {
101        reset();
102        for (Filter filter : filters) {
103            add(filter);
104        }
105    }
106
107    /**
108     * Clears the filters in use.
109     */
110    public void reset() {
111        hiddenFilters.clear();
112        disabledFilters.clear();
113    }
114
115    /**
116     * Adds a filter to the currently used filters
117     * @param filter the filter to add
118     * @throws SearchParseError if the search expression in the filter cannot be parsed
119     */
120    public void add(final Filter filter) throws SearchParseError {
121        if (!filter.enable) {
122            return;
123        }
124
125        FilterInfo fi = new FilterInfo(filter);
126        if (fi.isDelete) {
127            if (filter.hiding) {
128                // Remove only hide flag
129                hiddenFilters.add(fi);
130            } else {
131                // Remove both flags
132                disabledFilters.add(fi);
133                hiddenFilters.add(fi);
134            }
135        } else {
136            if (filter.mode == SearchMode.replace && filter.hiding) {
137                hiddenFilters.clear();
138                disabledFilters.clear();
139            }
140
141            disabledFilters.add(fi);
142            if (filter.hiding) {
143                hiddenFilters.add(fi);
144            }
145        }
146    }
147
148    /**
149     * Check if primitive is filtered.
150     * @param primitive the primitive to check
151     * @param hidden the minimum level required for the primitive to count as filtered
152     * @return when hidden is true, returns whether the primitive is hidden
153     * when hidden is false, returns whether the primitive is disabled or hidden
154     */
155    private static boolean isFiltered(OsmPrimitive primitive, boolean hidden) {
156        return hidden ? primitive.isDisabledAndHidden() : primitive.isDisabled();
157    }
158
159    /**
160     * Check if primitive is hidden explicitly.
161     * Only used for ways and relations.
162     * @param primitive the primitive to check
163     * @param hidden the level where the check is performed
164     * @return true, if at least one non-inverted filter applies to the primitive
165     */
166    private static boolean isFilterExplicit(OsmPrimitive primitive, boolean hidden) {
167        return hidden ? primitive.getHiddenType() : primitive.getDisabledType();
168    }
169
170    /**
171     * Check if all parent ways are filtered.
172     * @param primitive the primitive to check
173     * @param hidden parameter that indicates the minimum level of filtering:
174     * true when objects need to be hidden to count as filtered and
175     * false when it suffices to be disabled to count as filtered
176     * @return true if (a) there is at least one parent way
177     * (b) all parent ways are filtered at least at the level indicated by the
178     * parameter <code>hidden</code> and
179     * (c) at least one of the parent ways is explicitly filtered
180     */
181    private static boolean allParentWaysFiltered(OsmPrimitive primitive, boolean hidden) {
182        List<OsmPrimitive> refs = primitive.getReferrers();
183        boolean isExplicit = false;
184        for (OsmPrimitive p: refs) {
185            if (p instanceof Way) {
186                if (!isFiltered(p, hidden))
187                    return false;
188                isExplicit |= isFilterExplicit(p, hidden);
189            }
190        }
191        return isExplicit;
192    }
193
194    private static boolean oneParentWayNotFiltered(OsmPrimitive primitive, boolean hidden) {
195        List<OsmPrimitive> refs = primitive.getReferrers();
196        for (OsmPrimitive p: refs) {
197            if (p instanceof Way && !isFiltered(p, hidden))
198                return true;
199        }
200
201        return false;
202    }
203
204    private static boolean allParentMultipolygonsFiltered(OsmPrimitive primitive, boolean hidden) {
205        boolean isExplicit = false;
206        for (Relation r : new SubclassFilteredCollection<OsmPrimitive, Relation>(
207                primitive.getReferrers(), OsmPrimitive::isMultipolygon)) {
208            if (!isFiltered(r, hidden))
209                return false;
210            isExplicit |= isFilterExplicit(r, hidden);
211        }
212        return isExplicit;
213    }
214
215    private static boolean oneParentMultipolygonNotFiltered(OsmPrimitive primitive, boolean hidden) {
216        for (Relation r : new SubclassFilteredCollection<OsmPrimitive, Relation>(
217                primitive.getReferrers(), OsmPrimitive::isMultipolygon)) {
218            if (!isFiltered(r, hidden))
219                return true;
220        }
221        return false;
222    }
223
224    private static FilterType test(List<FilterInfo> filters, OsmPrimitive primitive, boolean hidden) {
225        if (primitive.isIncomplete() || primitive.isPreserved())
226            return FilterType.NOT_FILTERED;
227
228        boolean filtered = false;
229        // If the primitive is "explicitly" hidden by a non-inverted filter.
230        // Only interesting for nodes.
231        boolean explicitlyFiltered = false;
232
233        for (FilterInfo fi: filters) {
234            if (fi.isDelete) {
235                if (filtered && fi.match.match(primitive)) {
236                    filtered = false;
237                }
238            } else {
239                if ((!filtered || (!explicitlyFiltered && !fi.isInverted)) && fi.match.match(primitive)) {
240                    filtered = true;
241                    if (!fi.isInverted) {
242                        explicitlyFiltered = true;
243                    }
244                }
245            }
246        }
247
248        if (primitive instanceof Node) {
249            if (filtered) {
250                // If there is a parent way, that is not hidden, we  show the
251                // node anyway, unless there is no non-inverted filter that
252                // applies to the node directly.
253                if (explicitlyFiltered)
254                    return FilterType.PASSIV;
255                else {
256                    if (oneParentWayNotFiltered(primitive, hidden))
257                        return FilterType.NOT_FILTERED;
258                    else
259                        return FilterType.PASSIV;
260                }
261            } else {
262                if (!primitive.isTagged() && allParentWaysFiltered(primitive, hidden))
263                    // Technically not hidden by any filter, but we hide it anyway, if
264                    // it is untagged and all parent ways are hidden.
265                    return FilterType.PASSIV;
266                else
267                    return FilterType.NOT_FILTERED;
268            }
269        } else if (primitive instanceof Way) {
270            if (filtered) {
271                if (explicitlyFiltered)
272                    return FilterType.EXPLICIT;
273                else {
274                    if (oneParentMultipolygonNotFiltered(primitive, hidden))
275                        return FilterType.NOT_FILTERED;
276                    else
277                        return FilterType.PASSIV;
278                }
279            } else {
280                if (!primitive.isTagged() && allParentMultipolygonsFiltered(primitive, hidden))
281                    return FilterType.EXPLICIT;
282                else
283                    return FilterType.NOT_FILTERED;
284            }
285        } else {
286            if (filtered)
287                return explicitlyFiltered ? FilterType.EXPLICIT : FilterType.PASSIV;
288            else
289                return FilterType.NOT_FILTERED;
290        }
291
292    }
293
294    /**
295     * Check if primitive is hidden.
296     * The filter flags for all parent objects must be set correctly, when
297     * calling this method.
298     * @param primitive the primitive
299     * @return FilterType.NOT_FILTERED when primitive is not hidden;
300     * FilterType.EXPLICIT when primitive is hidden and there is a non-inverted
301     * filter that applies;
302     * FilterType.PASSIV when primitive is hidden and all filters that apply
303     * are inverted
304     */
305    public FilterType isHidden(OsmPrimitive primitive) {
306        return test(hiddenFilters, primitive, true);
307    }
308
309    /**
310     * Check if primitive is disabled.
311     * The filter flags for all parent objects must be set correctly, when
312     * calling this method.
313     * @param primitive the primitive
314     * @return FilterType.NOT_FILTERED when primitive is not disabled;
315     * FilterType.EXPLICIT when primitive is disabled and there is a non-inverted
316     * filter that applies;
317     * FilterType.PASSIV when primitive is disabled and all filters that apply
318     * are inverted
319     */
320    public FilterType isDisabled(OsmPrimitive primitive) {
321        return test(disabledFilters, primitive, false);
322    }
323
324    /**
325     * Returns a new {@code FilterMatcher} containing the given filters.
326     * @param filters filters to add to the resulting filter matcher
327     * @return a new {@code FilterMatcher} containing the given filters
328     * @throws SearchParseError if the search expression in a filter cannot be parsed
329     * @since 12383
330     */
331    public static FilterMatcher of(Filter... filters) throws SearchParseError {
332        FilterMatcher result = new FilterMatcher();
333        for (Filter filter : filters) {
334            result.add(filter);
335        }
336        return result;
337    }
338}