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diff --git a/core/string/fuzzy_search.cpp b/core/string/fuzzy_search.cpp
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+/**************************************************************************/
+/* fuzzy_search.cpp */
+/**************************************************************************/
+/* This file is part of: */
+/* GODOT ENGINE */
+/* https://godotengine.org */
+/**************************************************************************/
+/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
+/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
+/* */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the */
+/* "Software"), to deal in the Software without restriction, including */
+/* without limitation the rights to use, copy, modify, merge, publish, */
+/* distribute, sublicense, and/or sell copies of the Software, and to */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions: */
+/* */
+/* The above copyright notice and this permission notice shall be */
+/* included in all copies or substantial portions of the Software. */
+/* */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
+/**************************************************************************/
+
+#include "fuzzy_search.h"
+
+constexpr float cull_factor = 0.1f;
+constexpr float cull_cutoff = 30.0f;
+const String boundary_chars = "/\\-_.";
+
+static bool _is_valid_interval(const Vector2i &p_interval) {
+ // Empty intervals are represented as (-1, -1).
+ return p_interval.x >= 0 && p_interval.y >= p_interval.x;
+}
+
+static Vector2i _extend_interval(const Vector2i &p_a, const Vector2i &p_b) {
+ if (!_is_valid_interval(p_a)) {
+ return p_b;
+ }
+ if (!_is_valid_interval(p_b)) {
+ return p_a;
+ }
+ return Vector2i(MIN(p_a.x, p_b.x), MAX(p_a.y, p_b.y));
+}
+
+static bool _is_word_boundary(const String &p_str, int p_index) {
+ if (p_index == -1 || p_index == p_str.size()) {
+ return true;
+ }
+ return boundary_chars.find_char(p_str[p_index]) != -1;
+}
+
+bool FuzzySearchToken::try_exact_match(FuzzyTokenMatch &p_match, const String &p_target, int p_offset) const {
+ p_match.token_idx = idx;
+ p_match.token_length = string.length();
+ int match_idx = p_target.find(string, p_offset);
+ if (match_idx == -1) {
+ return false;
+ }
+ p_match.add_substring(match_idx, string.length());
+ return true;
+}
+
+bool FuzzySearchToken::try_fuzzy_match(FuzzyTokenMatch &p_match, const String &p_target, int p_offset, int p_miss_budget) const {
+ p_match.token_idx = idx;
+ p_match.token_length = string.length();
+ int run_start = -1;
+ int run_len = 0;
+
+ // Search for the subsequence p_token in p_target starting from p_offset, recording each substring for
+ // later scoring and display.
+ for (int i = 0; i < string.length(); i++) {
+ int new_offset = p_target.find_char(string[i], p_offset);
+ if (new_offset < 0) {
+ p_miss_budget--;
+ if (p_miss_budget < 0) {
+ return false;
+ }
+ } else {
+ if (run_start == -1 || p_offset != new_offset) {
+ if (run_start != -1) {
+ p_match.add_substring(run_start, run_len);
+ }
+ run_start = new_offset;
+ run_len = 1;
+ } else {
+ run_len += 1;
+ }
+ p_offset = new_offset + 1;
+ }
+ }
+
+ if (run_start != -1) {
+ p_match.add_substring(run_start, run_len);
+ }
+
+ return true;
+}
+
+void FuzzyTokenMatch::add_substring(int p_substring_start, int p_substring_length) {
+ substrings.append(Vector2i(p_substring_start, p_substring_length));
+ matched_length += p_substring_length;
+ Vector2i substring_interval = { p_substring_start, p_substring_start + p_substring_length - 1 };
+ interval = _extend_interval(interval, substring_interval);
+}
+
+bool FuzzyTokenMatch::intersects(const Vector2i &p_other_interval) const {
+ if (!_is_valid_interval(interval) || !_is_valid_interval(p_other_interval)) {
+ return false;
+ }
+ return interval.y >= p_other_interval.x && interval.x <= p_other_interval.y;
+}
+
+bool FuzzySearchResult::can_add_token_match(const FuzzyTokenMatch &p_match) const {
+ if (p_match.get_miss_count() > miss_budget) {
+ return false;
+ }
+
+ if (p_match.intersects(match_interval)) {
+ if (token_matches.size() == 1) {
+ return false;
+ }
+ for (const FuzzyTokenMatch &existing_match : token_matches) {
+ if (existing_match.intersects(p_match.interval)) {
+ return false;
+ }
+ }
+ }
+
+ return true;
+}
+
+bool FuzzyTokenMatch::is_case_insensitive(const String &p_original, const String &p_adjusted) const {
+ for (const Vector2i &substr : substrings) {
+ const int end = substr.x + substr.y;
+ for (int i = substr.x; i < end; i++) {
+ if (p_original[i] != p_adjusted[i]) {
+ return true;
+ }
+ }
+ }
+ return false;
+}
+
+void FuzzySearchResult::score_token_match(FuzzyTokenMatch &p_match, bool p_case_insensitive) const {
+ // This can always be tweaked more. The intuition is that exact matches should almost always
+ // be prioritized over broken up matches, and other criteria more or less act as tie breakers.
+
+ p_match.score = -20 * p_match.get_miss_count() - (p_case_insensitive ? 3 : 0);
+
+ for (const Vector2i &substring : p_match.substrings) {
+ // Score longer substrings higher than short substrings.
+ int substring_score = substring.y * substring.y;
+ // Score matches deeper in path higher than shallower matches
+ if (substring.x > dir_index) {
+ substring_score *= 2;
+ }
+ // Score matches on a word boundary higher than matches within a word
+ if (_is_word_boundary(target, substring.x - 1) || _is_word_boundary(target, substring.x + substring.y)) {
+ substring_score += 4;
+ }
+ // Score exact query matches higher than non-compact subsequence matches
+ if (substring.y == p_match.token_length) {
+ substring_score += 100;
+ }
+ p_match.score += substring_score;
+ }
+}
+
+void FuzzySearchResult::maybe_apply_score_bonus() {
+ // This adds a small bonus to results which match tokens in the same order they appear in the query.
+ int *token_range_starts = (int *)alloca(sizeof(int) * token_matches.size());
+
+ for (const FuzzyTokenMatch &match : token_matches) {
+ token_range_starts[match.token_idx] = match.interval.x;
+ }
+
+ int last = token_range_starts[0];
+ for (int i = 1; i < token_matches.size(); i++) {
+ if (last > token_range_starts[i]) {
+ return;
+ }
+ last = token_range_starts[i];
+ }
+
+ score += 1;
+}
+
+void FuzzySearchResult::add_token_match(const FuzzyTokenMatch &p_match) {
+ score += p_match.score;
+ match_interval = _extend_interval(match_interval, p_match.interval);
+ miss_budget -= p_match.get_miss_count();
+ token_matches.append(p_match);
+}
+
+void remove_low_scores(Vector<FuzzySearchResult> &p_results, float p_cull_score) {
+ // Removes all results with score < p_cull_score in-place.
+ int i = 0;
+ int j = p_results.size() - 1;
+ FuzzySearchResult *results = p_results.ptrw();
+
+ while (true) {
+ // Advances i to an element to remove and j to an element to keep.
+ while (j >= i && results[j].score < p_cull_score) {
+ j--;
+ }
+ while (i < j && results[i].score >= p_cull_score) {
+ i++;
+ }
+ if (i >= j) {
+ break;
+ }
+ results[i++] = results[j--];
+ }
+
+ p_results.resize(j + 1);
+}
+
+void FuzzySearch::sort_and_filter(Vector<FuzzySearchResult> &p_results) const {
+ if (p_results.is_empty()) {
+ return;
+ }
+
+ float avg_score = 0;
+ float max_score = 0;
+
+ for (const FuzzySearchResult &result : p_results) {
+ avg_score += result.score;
+ max_score = MAX(max_score, result.score);
+ }
+
+ // TODO: Tune scoring and culling here to display fewer subsequence soup matches when good matches
+ // are available.
+ avg_score /= p_results.size();
+ float cull_score = MIN(cull_cutoff, Math::lerp(avg_score, max_score, cull_factor));
+ remove_low_scores(p_results, cull_score);
+
+ struct FuzzySearchResultComparator {
+ bool operator()(const FuzzySearchResult &p_lhs, const FuzzySearchResult &p_rhs) const {
+ // Sort on (score, length, alphanumeric) to ensure consistent ordering.
+ if (p_lhs.score == p_rhs.score) {
+ if (p_lhs.target.length() == p_rhs.target.length()) {
+ return p_lhs.target < p_rhs.target;
+ }
+ return p_lhs.target.length() < p_rhs.target.length();
+ }
+ return p_lhs.score > p_rhs.score;
+ }
+ };
+
+ SortArray<FuzzySearchResult, FuzzySearchResultComparator> sorter;
+
+ if (p_results.size() > max_results) {
+ sorter.partial_sort(0, p_results.size(), max_results, p_results.ptrw());
+ p_results.resize(max_results);
+ } else {
+ sorter.sort(p_results.ptrw(), p_results.size());
+ }
+}
+
+void FuzzySearch::set_query(const String &p_query) {
+ tokens.clear();
+ for (const String &string : p_query.split(" ", false)) {
+ tokens.append({ static_cast<int>(tokens.size()), string });
+ }
+
+ case_sensitive = !p_query.is_lowercase();
+
+ struct TokenComparator {
+ bool operator()(const FuzzySearchToken &A, const FuzzySearchToken &B) const {
+ if (A.string.length() == B.string.length()) {
+ return A.idx < B.idx;
+ }
+ return A.string.length() > B.string.length();
+ }
+ };
+
+ // Prioritize matching longer tokens before shorter ones since match overlaps are not accepted.
+ tokens.sort_custom<TokenComparator>();
+}
+
+bool FuzzySearch::search(const String &p_target, FuzzySearchResult &p_result) const {
+ p_result.target = p_target;
+ p_result.dir_index = p_target.rfind_char('/');
+ p_result.miss_budget = max_misses;
+
+ String adjusted_target = case_sensitive ? p_target : p_target.to_lower();
+
+ // For each token, eagerly generate subsequences starting from index 0 and keep the best scoring one
+ // which does not conflict with prior token matches. This is not ensured to find the highest scoring
+ // combination of matches, or necessarily the highest scoring single subsequence, as it only considers
+ // eager subsequences for a given index, and likewise eagerly finds matches for each token in sequence.
+ for (const FuzzySearchToken &token : tokens) {
+ FuzzyTokenMatch best_match;
+ int offset = start_offset;
+
+ while (true) {
+ FuzzyTokenMatch match;
+ if (allow_subsequences) {
+ if (!token.try_fuzzy_match(match, adjusted_target, offset, p_result.miss_budget)) {
+ break;
+ }
+ } else {
+ if (!token.try_exact_match(match, adjusted_target, offset)) {
+ break;
+ }
+ }
+ if (p_result.can_add_token_match(match)) {
+ p_result.score_token_match(match, match.is_case_insensitive(p_target, adjusted_target));
+ if (best_match.token_idx == -1 || best_match.score < match.score) {
+ best_match = match;
+ }
+ }
+ if (_is_valid_interval(match.interval)) {
+ offset = match.interval.x + 1;
+ } else {
+ break;
+ }
+ }
+
+ if (best_match.token_idx == -1) {
+ return false;
+ }
+
+ p_result.add_token_match(best_match);
+ }
+
+ p_result.maybe_apply_score_bonus();
+ return true;
+}
+
+void FuzzySearch::search_all(const PackedStringArray &p_targets, Vector<FuzzySearchResult> &p_results) const {
+ p_results.clear();
+
+ for (const String &target : p_targets) {
+ FuzzySearchResult result;
+ if (search(target, result)) {
+ p_results.append(result);
+ }
+ }
+
+ sort_and_filter(p_results);
+}