rmuir commented on a change in pull request #2423: URL: https://github.com/apache/lucene-solr/pull/2423#discussion_r581337571
########## File path: lucene/analysis/common/src/java/org/apache/lucene/analysis/hunspell/AffixCondition.java ########## @@ -0,0 +1,214 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.lucene.analysis.hunspell; + +import static org.apache.lucene.analysis.hunspell.AffixKind.PREFIX; +import static org.apache.lucene.analysis.hunspell.AffixKind.SUFFIX; + +import java.util.ArrayList; +import java.util.List; +import java.util.regex.PatternSyntaxException; +import java.util.stream.Collectors; +import org.apache.lucene.util.automaton.CharacterRunAutomaton; +import org.apache.lucene.util.automaton.RegExp; + +/** + * Checks the "condition" part of affix definition, as in + * + * <pre>PFX flag stripping prefix [condition [morphological_fields...]]</pre> + */ +interface AffixCondition { + String ALWAYS_TRUE_KEY = ".*"; + AffixCondition ALWAYS_TRUE = (word, offset, length) -> true; + AffixCondition ALWAYS_FALSE = (word, offset, length) -> false; + + default boolean acceptsStem(String stem) { + return acceptsStem(stem.toCharArray(), 0, stem.length()); + } + + /** + * @return whether the given word matches this condition as a stem with both "strip" and "affix" + * removed + */ + boolean acceptsStem(char[] word, int offset, int length); + + /** + * @return a key used to deduplicate same condition+strip+kind triples. For trivial conditions + * that need no check, {@link #ALWAYS_TRUE_KEY} is returned. + */ + static String uniqueKey(AffixKind kind, String strip, String condition) { + if (".".equals(condition) + || kind == PREFIX && strip.startsWith(condition) + || kind == SUFFIX && strip.endsWith(condition) && !isRegexp(condition)) { + return ALWAYS_TRUE_KEY; + } + return kind == SUFFIX ? ".*" + condition : condition + ".*"; + } + + /** + * Analyzes the given affix kind, strip and condition and returns an object able to efficiently + * check that condition. + */ + static AffixCondition compile(AffixKind kind, String strip, String condition, String line) { + String stemCondition = removeStrip(strip, condition, line, kind); + if (stemCondition == null) { + return ALWAYS_FALSE; + } + + if (stemCondition.isEmpty()) { + return ALWAYS_TRUE; + } + + if (!isRegexp(stemCondition)) { + return substringCondition(kind, stemCondition); + } + + try { + return regexpCondition(kind, escapeDash(stemCondition)); + } catch (IllegalArgumentException e) { + throw new IllegalArgumentException("On line: " + line, e); + } + } + + private static boolean isRegexp(String condition) { + return condition.contains("[") || condition.contains(".") || condition.contains("-"); + } + + /** Removes the "strip" from "condition", to check only the remaining stem part */ + private static String removeStrip(String strip, String condition, String line, AffixKind kind) { + if (!isRegexp(condition)) { + if (kind == SUFFIX && condition.endsWith(strip)) { + return condition.substring(0, condition.length() - strip.length()); + } + if (kind == PREFIX && condition.startsWith(strip)) { + return condition.substring(strip.length()); + } + } + + List<String> charPatterns = parse(condition); + try { + if (charPatterns.size() < strip.length()) { + String regexp = unitePatterns(charPatterns); + return strip.matches(kind == SUFFIX ? ".*" + regexp : regexp + ".*") ? "" : null; + } + + int stripRangeStart = kind == PREFIX ? 0 : charPatterns.size() - strip.length(); + int stripRangeEnd = kind == PREFIX ? strip.length() : charPatterns.size(); + if (!strip.isEmpty() + && !strip.matches(unitePatterns(charPatterns.subList(stripRangeStart, stripRangeEnd)))) { + return null; + } + + if (kind == PREFIX) { + return unitePatterns(charPatterns.subList(stripRangeEnd, charPatterns.size())); + } + return unitePatterns(charPatterns.subList(0, stripRangeStart)); + } catch (PatternSyntaxException e) { + throw new IllegalArgumentException("On line " + line, e); + } + } + + /** Produces a regexp from groups returned by {@link #parse} */ + private static String unitePatterns(List<String> charPatterns) { + return charPatterns.stream() + .map(s -> s.length() == 1 && "()?$^{}*+|\\".indexOf(s.charAt(0)) >= 0 ? "\\" + s : s) + .collect(Collectors.joining()); + } Review comment: I see. I think I just get worried when I see escaping for `RegExp` syntax. Maybe as a `TODO` for the future we can avoid using RegExp class at all here? We could perhaps skip the parsing step and build the `Automaton` we need programmatically with `org.apache.util.automaton` APIs? ########## File path: lucene/analysis/common/src/java/org/apache/lucene/analysis/hunspell/AffixCondition.java ########## @@ -0,0 +1,214 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.lucene.analysis.hunspell; + +import static org.apache.lucene.analysis.hunspell.AffixKind.PREFIX; +import static org.apache.lucene.analysis.hunspell.AffixKind.SUFFIX; + +import java.util.ArrayList; +import java.util.List; +import java.util.regex.PatternSyntaxException; +import java.util.stream.Collectors; +import org.apache.lucene.util.automaton.CharacterRunAutomaton; +import org.apache.lucene.util.automaton.RegExp; + +/** + * Checks the "condition" part of affix definition, as in + * + * <pre>PFX flag stripping prefix [condition [morphological_fields...]]</pre> + */ +interface AffixCondition { + String ALWAYS_TRUE_KEY = ".*"; + AffixCondition ALWAYS_TRUE = (word, offset, length) -> true; + AffixCondition ALWAYS_FALSE = (word, offset, length) -> false; + + default boolean acceptsStem(String stem) { + return acceptsStem(stem.toCharArray(), 0, stem.length()); + } + + /** + * @return whether the given word matches this condition as a stem with both "strip" and "affix" + * removed + */ + boolean acceptsStem(char[] word, int offset, int length); + + /** + * @return a key used to deduplicate same condition+strip+kind triples. For trivial conditions + * that need no check, {@link #ALWAYS_TRUE_KEY} is returned. + */ + static String uniqueKey(AffixKind kind, String strip, String condition) { + if (".".equals(condition) + || kind == PREFIX && strip.startsWith(condition) + || kind == SUFFIX && strip.endsWith(condition) && !isRegexp(condition)) { + return ALWAYS_TRUE_KEY; + } + return kind == SUFFIX ? ".*" + condition : condition + ".*"; + } + + /** + * Analyzes the given affix kind, strip and condition and returns an object able to efficiently + * check that condition. + */ + static AffixCondition compile(AffixKind kind, String strip, String condition, String line) { + String stemCondition = removeStrip(strip, condition, line, kind); + if (stemCondition == null) { + return ALWAYS_FALSE; + } + + if (stemCondition.isEmpty()) { + return ALWAYS_TRUE; + } + + if (!isRegexp(stemCondition)) { + return substringCondition(kind, stemCondition); + } + + try { + return regexpCondition(kind, escapeDash(stemCondition)); + } catch (IllegalArgumentException e) { + throw new IllegalArgumentException("On line: " + line, e); + } + } + + private static boolean isRegexp(String condition) { + return condition.contains("[") || condition.contains(".") || condition.contains("-"); + } + + /** Removes the "strip" from "condition", to check only the remaining stem part */ + private static String removeStrip(String strip, String condition, String line, AffixKind kind) { + if (!isRegexp(condition)) { + if (kind == SUFFIX && condition.endsWith(strip)) { + return condition.substring(0, condition.length() - strip.length()); + } + if (kind == PREFIX && condition.startsWith(strip)) { + return condition.substring(strip.length()); + } + } + + List<String> charPatterns = parse(condition); + try { + if (charPatterns.size() < strip.length()) { + String regexp = unitePatterns(charPatterns); + return strip.matches(kind == SUFFIX ? ".*" + regexp : regexp + ".*") ? "" : null; + } + + int stripRangeStart = kind == PREFIX ? 0 : charPatterns.size() - strip.length(); + int stripRangeEnd = kind == PREFIX ? strip.length() : charPatterns.size(); + if (!strip.isEmpty() + && !strip.matches(unitePatterns(charPatterns.subList(stripRangeStart, stripRangeEnd)))) { + return null; + } + + if (kind == PREFIX) { + return unitePatterns(charPatterns.subList(stripRangeEnd, charPatterns.size())); + } + return unitePatterns(charPatterns.subList(0, stripRangeStart)); + } catch (PatternSyntaxException e) { + throw new IllegalArgumentException("On line " + line, e); + } + } + + /** Produces a regexp from groups returned by {@link #parse} */ + private static String unitePatterns(List<String> charPatterns) { + return charPatterns.stream() + .map(s -> s.length() == 1 && "()?$^{}*+|\\".indexOf(s.charAt(0)) >= 0 ? "\\" + s : s) + .collect(Collectors.joining()); + } + + /** Splits condition into small regexps, each standing for a single char to be matched. */ + private static List<String> parse(String condition) { + List<String> groups = new ArrayList<>(); + for (int i = 0; i < condition.length(); i++) { + char c = condition.charAt(i); + if (c == '[') { + int closing = condition.indexOf(']', i + 1); + if (closing <= 0) { + groups.add(condition.substring(i) + "]"); + break; + } + + groups.add(condition.substring(i, closing + 1)); + i = closing; + } else if (c == '.') { + groups.add("."); + } else { + groups.add(String.valueOf(c)); + } + } + return groups; + } + + private static AffixCondition substringCondition(AffixKind kind, String stemCondition) { + boolean forSuffix = kind == AffixKind.SUFFIX; + int condLength = stemCondition.length(); + return (word, offset, length) -> { + if (length < condLength) { + return false; + } + int matchStart = forSuffix ? offset + length - condLength : offset; + for (int i = 0; i < condLength; i++) { + if (stemCondition.charAt(i) != word[matchStart + i]) { + return false; + } + } + return true; + }; + } + + private static AffixCondition regexpCondition(AffixKind kind, String stemCondition) { + boolean forSuffix = kind == AffixKind.SUFFIX; + int condLength = parse(stemCondition).size(); + CharacterRunAutomaton automaton = + new CharacterRunAutomaton(conditionRegexp(stemCondition).toAutomaton()); + return (word, offset, length) -> + length >= condLength + && automaton.run(word, forSuffix ? offset + length - condLength : offset, condLength); + } + + private static RegExp conditionRegexp(String regex) { + try { + return new RegExp(regex, RegExp.NONE); + } catch (IllegalArgumentException e) { + if (e.getMessage().contains("expected ']'")) { + return conditionRegexp(regex + "]"); Review comment: Maybe my other comment on the "unite" method is related. Ideally we could avoid RegExp class. RegExp class just parses and then uses automaton API to build the result. But if we bypass the parsing and build the DFA we want explicitly, we may be able to avoid some hassles. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org
