donnerpeter commented on a change in pull request #2423: URL: https://github.com/apache/lucene-solr/pull/2423#discussion_r581270914
########## 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: A hack (moved from Dictionary) to mimic Hunspell's behavior, which (probably accidentally) allows [ ] groups to be unclosed ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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