Add regexp interval source (#1917)

* Add regexp interval source

Add a regexp interval source provider so people can use regular
expressions inside of intervals queries.

Signed-off-by: Matt Weber <matt@mattweber.org>

* Fixes

- register regexp interval in SearchModule
- use fully-qualified name for lucene RegExp
- get rid of unnecessary variable

Signed-off-by: Matt Weber <matt@mattweber.org>

server/src/main/java/org/opensearch/index/query/IntervalsSourceProvider.java

@@ -39,6 +39,7 @@ import org.apache.lucene.queries.intervals.Intervals;
 import org.apache.lucene.queries.intervals.IntervalsSource;
 import org.apache.lucene.search.FuzzyQuery;
 import org.apache.lucene.util.BytesRef;
+import org.apache.lucene.util.automaton.CompiledAutomaton;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.common.ParseField;
@@ -101,12 +102,14 @@ public abstract class IntervalsSourceProvider implements NamedWriteable, ToXCont
                 return Prefix.fromXContent(parser);
             case "wildcard":
                 return Wildcard.fromXContent(parser);
+            case "regexp":
+                return Regexp.fromXContent(parser);
             case "fuzzy":
                 return Fuzzy.fromXContent(parser);
         }
         throw new ParsingException(
             parser.getTokenLocation(),
-            "Unknown interval type [" + parser.currentName() + "], expecting one of [match, any_of, all_of, prefix, wildcard]"
+            "Unknown interval type [" + parser.currentName() + "], expecting one of [match, any_of, all_of, prefix, wildcard, regexp]"
         );
     }
 
@@ -631,6 +634,155 @@ public abstract class IntervalsSourceProvider implements NamedWriteable, ToXCont
         }
     }
 
+    public static class Regexp extends IntervalsSourceProvider {
+
+        public static final String NAME = "regexp";
+        public static final int DEFAULT_FLAGS_VALUE = RegexpFlag.ALL.value();
+
+        private final String pattern;
+        private final int flags;
+        private final String useField;
+        private final Integer maxExpansions;
+
+        public Regexp(String pattern, int flags, String useField, Integer maxExpansions) {
+            this.pattern = pattern;
+            this.flags = flags;
+            this.useField = useField;
+            this.maxExpansions = (maxExpansions != null && maxExpansions > 0) ? maxExpansions : null;
+        }
+
+        public Regexp(StreamInput in) throws IOException {
+            this.pattern = in.readString();
+            this.flags = in.readVInt();
+            this.useField = in.readOptionalString();
+            this.maxExpansions = in.readOptionalVInt();
+        }
+
+        @Override
+        public IntervalsSource getSource(QueryShardContext context, MappedFieldType fieldType) {
+            final org.apache.lucene.util.automaton.RegExp regexp = new org.apache.lucene.util.automaton.RegExp(pattern, flags);
+            final CompiledAutomaton automaton = new CompiledAutomaton(regexp.toAutomaton());
+
+            if (useField != null) {
+                fieldType = context.fieldMapper(useField);
+                assert fieldType != null;
+                checkPositions(fieldType);
+
+                IntervalsSource regexpSource = maxExpansions == null
+                    ? Intervals.multiterm(automaton, regexp.toString())
+                    : Intervals.multiterm(automaton, maxExpansions, regexp.toString());
+                return Intervals.fixField(useField, regexpSource);
+            } else {
+                checkPositions(fieldType);
+                return maxExpansions == null
+                    ? Intervals.multiterm(automaton, regexp.toString())
+                    : Intervals.multiterm(automaton, maxExpansions, regexp.toString());
+            }
+        }
+
+        private void checkPositions(MappedFieldType type) {
+            if (type.getTextSearchInfo().hasPositions() == false) {
+                throw new IllegalArgumentException("Cannot create intervals over field [" + type.name() + "] with no positions indexed");
+            }
+        }
+
+        @Override
+        public void extractFields(Set<String> fields) {
+            if (useField != null) {
+                fields.add(useField);
+            }
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            Regexp regexp = (Regexp) o;
+            return Objects.equals(pattern, regexp.pattern)
+                && Objects.equals(flags, regexp.flags)
+                && Objects.equals(useField, regexp.useField)
+                && Objects.equals(maxExpansions, regexp.maxExpansions);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(pattern, flags, useField, maxExpansions);
+        }
+
+        @Override
+        public String getWriteableName() {
+            return NAME;
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeString(pattern);
+            out.writeVInt(flags);
+            out.writeOptionalString(useField);
+            out.writeOptionalVInt(maxExpansions);
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            builder.startObject(NAME);
+            builder.field("pattern", pattern);
+            if (flags != DEFAULT_FLAGS_VALUE) {
+                builder.field("flags_value", flags);
+            }
+            if (useField != null) {
+                builder.field("use_field", useField);
+            }
+            if (maxExpansions != null) {
+                builder.field("max_expansions", maxExpansions);
+            }
+            builder.endObject();
+            return builder;
+        }
+
+        private static final ConstructingObjectParser<Regexp, Void> PARSER = new ConstructingObjectParser<>(NAME, args -> {
+            String pattern = (String) args[0];
+            String flags = (String) args[1];
+            Integer flagsValue = (Integer) args[2];
+            String useField = (String) args[3];
+            Integer maxExpansions = (Integer) args[4];
+
+            if (flagsValue != null) {
+                return new Regexp(pattern, flagsValue, useField, maxExpansions);
+            } else if (flags != null) {
+                return new Regexp(pattern, RegexpFlag.resolveValue(flags), useField, maxExpansions);
+            } else {
+                return new Regexp(pattern, DEFAULT_FLAGS_VALUE, useField, maxExpansions);
+            }
+        });
+        static {
+            PARSER.declareString(constructorArg(), new ParseField("pattern"));
+            PARSER.declareString(optionalConstructorArg(), new ParseField("flags"));
+            PARSER.declareInt(optionalConstructorArg(), new ParseField("flags_value"));
+            PARSER.declareString(optionalConstructorArg(), new ParseField("use_field"));
+            PARSER.declareInt(optionalConstructorArg(), new ParseField("max_expansions"));
+        }
+
+        public static Regexp fromXContent(XContentParser parser) throws IOException {
+            return PARSER.parse(parser, null);
+        }
+
+        String getPattern() {
+            return pattern;
+        }
+
+        int getFlags() {
+            return flags;
+        }
+
+        String getUseField() {
+            return useField;
+        }
+
+        Integer getMaxExpansions() {
+            return maxExpansions;
+        }
+    }
+
     public static class Wildcard extends IntervalsSourceProvider {
 
         public static final String NAME = "wildcard";

server/src/main/java/org/opensearch/search/SearchModule.java

@@ -1254,6 +1254,11 @@ public class SearchModule {
                     IntervalsSourceProvider.Wildcard.NAME,
                     IntervalsSourceProvider.Wildcard::new
                 ),
+                new NamedWriteableRegistry.Entry(
+                    IntervalsSourceProvider.class,
+                    IntervalsSourceProvider.Regexp.NAME,
+                    IntervalsSourceProvider.Regexp::new
+                ),
                 new NamedWriteableRegistry.Entry(
                     IntervalsSourceProvider.class,
                     IntervalsSourceProvider.Fuzzy.NAME,

server/src/test/java/org/opensearch/index/query/IntervalQueryBuilderTests.java

@@ -42,6 +42,8 @@ import org.apache.lucene.search.FuzzyQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.util.BytesRef;
+import org.apache.lucene.util.automaton.CompiledAutomaton;
+import org.apache.lucene.util.automaton.RegExp;
 import org.opensearch.common.ParsingException;
 import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
@@ -686,6 +688,114 @@ public class IntervalQueryBuilderTests extends AbstractQueryTestCase<IntervalQue
         });
     }
 
+    private static IntervalsSource buildRegexpSource(String pattern, int flags, Integer maxExpansions) {
+        final RegExp regexp = new RegExp(pattern, flags);
+        CompiledAutomaton automaton = new CompiledAutomaton(regexp.toAutomaton());
+
+        if (maxExpansions != null) {
+            return Intervals.multiterm(automaton, maxExpansions, regexp.toString());
+        } else {
+            return Intervals.multiterm(automaton, regexp.toString());
+        }
+    }
+
+    public void testRegexp() throws IOException {
+        final int DEFAULT_FLAGS = RegexpFlag.ALL.value();
+        String json = "{ \"intervals\" : { \"" + TEXT_FIELD_NAME + "\": { " + "\"regexp\" : { \"pattern\" : \"te.m\" } } } }";
+
+        IntervalQueryBuilder builder = (IntervalQueryBuilder) parseQuery(json);
+        Query expected = new IntervalQuery(TEXT_FIELD_NAME, buildRegexpSource("te.m", DEFAULT_FLAGS, null));
+        assertEquals(expected, builder.toQuery(createShardContext()));
+
+        String no_positions_json = "{ \"intervals\" : { \""
+            + NO_POSITIONS_FIELD
+            + "\": { "
+            + "\"regexp\" : { \"pattern\" : \"[Tt]erm\" } } } }";
+        expectThrows(IllegalArgumentException.class, () -> {
+            IntervalQueryBuilder builder1 = (IntervalQueryBuilder) parseQuery(no_positions_json);
+            builder1.toQuery(createShardContext());
+        });
+
+        String fixed_field_json = "{ \"intervals\" : { \""
+            + TEXT_FIELD_NAME
+            + "\": { "
+            + "\"regexp\" : { \"pattern\" : \"te.m\", \"use_field\" : \"masked_field\" } } } }";
+
+        builder = (IntervalQueryBuilder) parseQuery(fixed_field_json);
+        expected = new IntervalQuery(TEXT_FIELD_NAME, Intervals.fixField(MASKED_FIELD, buildRegexpSource("te.m", DEFAULT_FLAGS, null)));
+        assertEquals(expected, builder.toQuery(createShardContext()));
+
+        String fixed_field_json_no_positions = "{ \"intervals\" : { \""
+            + TEXT_FIELD_NAME
+            + "\": { "
+            + "\"regexp\" : { \"pattern\" : \"te.m\", \"use_field\" : \""
+            + NO_POSITIONS_FIELD
+            + "\" } } } }";
+        expectThrows(IllegalArgumentException.class, () -> {
+            IntervalQueryBuilder builder1 = (IntervalQueryBuilder) parseQuery(fixed_field_json_no_positions);
+            builder1.toQuery(createShardContext());
+        });
+
+        String flags_json = "{ \"intervals\" : { \""
+            + TEXT_FIELD_NAME
+            + "\": { "
+            + "\"regexp\" : { \"pattern\" : \"te.m\", \"flags\" : \"NONE\" } } } }";
+
+        builder = (IntervalQueryBuilder) parseQuery(flags_json);
+        expected = new IntervalQuery(TEXT_FIELD_NAME, buildRegexpSource("te.m", RegexpFlag.NONE.value(), null));
+        assertEquals(expected, builder.toQuery(createShardContext()));
+
+        String flags_value_json = "{ \"intervals\" : { \""
+            + TEXT_FIELD_NAME
+            + "\": { "
+            + "\"regexp\" : { \"pattern\" : \"te.m\", \"flags_value\" : \""
+            + RegexpFlag.ANYSTRING.value()
+            + "\" } } } }";
+
+        builder = (IntervalQueryBuilder) parseQuery(flags_value_json);
+        expected = new IntervalQuery(TEXT_FIELD_NAME, buildRegexpSource("te.m", RegexpFlag.ANYSTRING.value(), null));
+        assertEquals(expected, builder.toQuery(createShardContext()));
+
+        String regexp_max_expand_json = "{ \"intervals\" : { \""
+            + TEXT_FIELD_NAME
+            + "\": { "
+            + "\"regexp\" : { \"pattern\" : \"te.m\", \"max_expansions\" : 500 } } } }";
+
+        builder = (IntervalQueryBuilder) parseQuery(regexp_max_expand_json);
+        expected = new IntervalQuery(TEXT_FIELD_NAME, buildRegexpSource("te.m", DEFAULT_FLAGS, 500));
+        assertEquals(expected, builder.toQuery(createShardContext()));
+
+        String regexp_neg_max_expand_json = "{ \"intervals\" : { \""
+            + TEXT_FIELD_NAME
+            + "\": { "
+            + "\"regexp\" : { \"pattern\" : \"te.m\", \"max_expansions\" : -20 } } } }";
+
+        builder = (IntervalQueryBuilder) parseQuery(regexp_neg_max_expand_json);
+        // max expansions use default
+        expected = new IntervalQuery(TEXT_FIELD_NAME, buildRegexpSource("te.m", DEFAULT_FLAGS, null));
+        assertEquals(expected, builder.toQuery(createShardContext()));
+
+        String regexp_over_max_expand_json = "{ \"intervals\" : { \""
+            + TEXT_FIELD_NAME
+            + "\": { "
+            + "\"regexp\" : { \"pattern\" : \"te.m\", \"max_expansions\" : "
+            + (BooleanQuery.getMaxClauseCount() + 1)
+            + " } } } }";
+        expectThrows(IllegalArgumentException.class, () -> {
+            IntervalQueryBuilder builder1 = (IntervalQueryBuilder) parseQuery(regexp_over_max_expand_json);
+            builder1.toQuery(createShardContext());
+        });
+
+        String regexp_max_expand_with_flags_json = "{ \"intervals\" : { \""
+            + TEXT_FIELD_NAME
+            + "\": { "
+            + "\"regexp\" : { \"pattern\" : \"te.m\", \"flags\": \"NONE\", \"max_expansions\" : 500 } } } }";
+
+        builder = (IntervalQueryBuilder) parseQuery(regexp_max_expand_with_flags_json);
+        expected = new IntervalQuery(TEXT_FIELD_NAME, buildRegexpSource("te.m", RegexpFlag.NONE.value(), 500));
+        assertEquals(expected, builder.toQuery(createShardContext()));
+    }
+
     private static IntervalsSource buildFuzzySource(String term, String label, int prefixLength, boolean transpositions, int editDistance) {
         FuzzyQuery fq = new FuzzyQuery(new Term("field", term), editDistance, prefixLength, 128, transpositions);
         return Intervals.multiterm(fq.getAutomata(), label);

server/src/test/java/org/opensearch/index/query/RegexpIntervalsSourceProviderTests.java

@@ -0,0 +1,79 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.query;
+
+import static org.opensearch.index.query.IntervalsSourceProvider.Regexp;
+import static org.opensearch.index.query.IntervalsSourceProvider.fromXContent;
+
+import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.test.AbstractSerializingTestCase;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.List;
+
+public class RegexpIntervalsSourceProviderTests extends AbstractSerializingTestCase<Regexp> {
+    private static final List<String> FLAGS = Arrays.asList("INTERSECTION", "COMPLEMENT", "EMPTY", "ANYSTRING", "INTERVAL", "NONE");
+
+    @Override
+    protected Regexp createTestInstance() {
+        return createRandomRegexp();
+    }
+
+    static Regexp createRandomRegexp() {
+        return new Regexp(
+            randomAlphaOfLengthBetween(0, 3) + (randomBoolean() ? ".*?" : "." + randomAlphaOfLength(4)) + randomAlphaOfLengthBetween(0, 5),
+            randomBoolean() ? RegexpFlag.resolveValue(randomFrom(FLAGS)) : RegexpFlag.ALL.value(),
+            randomBoolean() ? randomAlphaOfLength(10) : null,
+            randomBoolean() ? randomIntBetween(-1, Integer.MAX_VALUE) : null
+        );
+    }
+
+    @Override
+    protected Regexp mutateInstance(Regexp instance) throws IOException {
+        String pattern = instance.getPattern();
+        int flags = instance.getFlags();
+        String useField = instance.getUseField();
+        Integer maxExpansions = instance.getMaxExpansions();
+        int ran = between(0, 3);
+        switch (ran) {
+            case 0:
+                pattern += randomBoolean() ? ".*?" : randomAlphaOfLength(5);
+                break;
+            case 1:
+                flags = (flags == RegexpFlag.ALL.value()) ? RegexpFlag.resolveValue(randomFrom(FLAGS)) : RegexpFlag.ALL.value();
+                break;
+            case 2:
+                useField = useField == null ? randomAlphaOfLength(5) : null;
+                break;
+            case 3:
+                maxExpansions = maxExpansions == null ? randomIntBetween(1, Integer.MAX_VALUE) : null;
+                break;
+            default:
+                throw new AssertionError("Illegal randomisation branch");
+        }
+        return new Regexp(pattern, flags, useField, maxExpansions);
+    }
+
+    @Override
+    protected Writeable.Reader<Regexp> instanceReader() {
+        return Regexp::new;
+    }
+
+    @Override
+    protected Regexp doParseInstance(XContentParser parser) throws IOException {
+        if (parser.nextToken() == XContentParser.Token.START_OBJECT) {
+            parser.nextToken();
+        }
+        Regexp regexp = (Regexp) fromXContent(parser);
+        assertEquals(XContentParser.Token.END_OBJECT, parser.nextToken());
+        return regexp;
+    }
+}