refactor
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randogoth
parent
ac62865cd6
commit
7409b9d4cd
3 changed files with 57 additions and 79 deletions
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@ -2,7 +2,6 @@ import 'dart:convert';
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import 'dart:io';
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import 'package:http/http.dart' as http;
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import 'package:dart_geohash/dart_geohash.dart';
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import 'package:latlong2/latlong.dart';
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import 'package:turf/turf.dart';
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import 'package:path_provider/path_provider.dart';
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import 'package:shared_preferences/shared_preferences.dart';
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@ -12,7 +11,6 @@ class GeoMetadataLookup {
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final String apiUrl;
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final bool enableCacheExpiration;
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final Duration cacheExpirationDuration;
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final Distance distance = const Distance();
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final http.Client httpClient;
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Directory? cacheDir;
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@ -36,55 +34,48 @@ class GeoMetadataLookup {
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Future<List<Map<String, dynamic>>> lookup(double latitude, double longitude, {double distanceThreshold = 10.0}) async {
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final String geohash = GeoHasher().encode(latitude, longitude, precision: 4);
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if (kIsWeb) {
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return _lookupWeb(geohash);
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} else {
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return _lookupFile(geohash, latitude, longitude, distanceThreshold);
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}
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return kIsWeb
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? await _lookupWeb(geohash, latitude, longitude, distanceThreshold)
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: await _lookupFile(geohash, latitude, longitude, distanceThreshold);
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}
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Future<List<Map<String, dynamic>>> _lookupFile(String geohash, double latitude, double longitude, double distanceThreshold) async {
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final File cacheFile = File('${cacheDir?.path}/$geohash.geojson.gz');
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await _updateLastAccessTime(geohash);
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final bool isExpired = await _isCacheExpired(geohash);
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if (!cacheFile.existsSync() || isExpired) {
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if (!cacheFile.existsSync() || await _isCacheExpired(geohash)) {
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await _downloadGeoJson(geohash, cacheFile);
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} else {
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await _updateLastAccessTime(geohash);
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}
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final String geoJsonStr = utf8.decode(GZipCodec().decode(cacheFile.readAsBytesSync()));
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final Map<String, dynamic> geoJson = jsonDecode(geoJsonStr);
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return _findMetadata(latitude, longitude, geoJson, distanceThreshold);
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return _findMetadata(latitude, longitude, jsonDecode(geoJsonStr), distanceThreshold);
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}
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Future<List<Map<String, dynamic>>> _lookupWeb(String geohash) async {
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Future<List<Map<String, dynamic>>> _lookupWeb(String geohash, double latitude, double longitude, double distanceThreshold) async {
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final prefs = await SharedPreferences.getInstance();
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final String? cachedGeoJson = prefs.getString('geojson_$geohash');
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if (cachedGeoJson == null || await _isCacheExpired(geohash)) {
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final response = await http.get(Uri.parse('$apiUrl?geohash=$geohash&format=geojson'));
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final response = await httpClient.get(Uri.parse('$apiUrl?geohash=$geohash&format=geojson'));
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if (response.statusCode == 200) {
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await prefs.setString('geojson_$geohash', utf8.decode(response.bodyBytes));
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final geoJsonStr = utf8.decode(response.bodyBytes);
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await prefs.setString('geojson_$geohash', geoJsonStr);
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await _updateLastAccessTime(geohash);
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return _findMetadata(0, 0, jsonDecode(utf8.decode(response.bodyBytes)), 10.0);
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} else {
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throw Exception('Failed to download GeoJSON for geohash: $geohash');
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return _findMetadata(latitude, longitude, jsonDecode(geoJsonStr), distanceThreshold);
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}
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throw Exception('Failed to download GeoJSON for geohash: $geohash');
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}
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return _findMetadata(0, 0, jsonDecode(cachedGeoJson), 10.0);
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await _updateLastAccessTime(geohash);
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return _findMetadata(latitude, longitude, jsonDecode(cachedGeoJson), distanceThreshold);
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}
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Future<void> _downloadGeoJson(String geohash, File cacheFile) async {
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final response = await httpClient.get(Uri.parse('$apiUrl?geohash=$geohash&format=geojson'));
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if (response.statusCode == 200) {
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cacheFile.writeAsBytesSync(GZipCodec().encode(response.bodyBytes));
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await _updateLastAccessTime(geohash);
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} else {
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throw Exception('Failed to download GeoJSON for geohash: $geohash');
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final response = await httpClient.get(Uri.parse('$apiUrl?geohash=$geohash&format=geojson'));
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if (response.statusCode == 200) {
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cacheFile.writeAsBytesSync(GZipCodec().encode(response.bodyBytes));
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await _updateLastAccessTime(geohash);
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} else {
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throw Exception('Failed to download GeoJSON for geohash: $geohash');
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}
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}
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}
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Future<void> _updateLastAccessTime(String geohash) async {
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final prefs = await SharedPreferences.getInstance();
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@ -95,8 +86,7 @@ class GeoMetadataLookup {
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if (!enableCacheExpiration) return false;
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final prefs = await SharedPreferences.getInstance();
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final int? lastAccess = prefs.getInt('cache_last_access_$geohash');
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if (lastAccess == null) return true;
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return DateTime.now().difference(DateTime.fromMillisecondsSinceEpoch(lastAccess)) > cacheExpirationDuration;
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return lastAccess == null || DateTime.now().difference(DateTime.fromMillisecondsSinceEpoch(lastAccess)) > cacheExpirationDuration;
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}
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Future<void> _cleanExpiredCache() async {
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@ -106,9 +96,7 @@ class GeoMetadataLookup {
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final geohash = key.replaceFirst('cache_last_access_', '');
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if (await _isCacheExpired(geohash)) {
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final File cacheFile = File('${cacheDir?.path}/$geohash.geojson.gz');
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if (cacheFile.existsSync()) {
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cacheFile.deleteSync();
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}
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if (cacheFile.existsSync()) cacheFile.deleteSync();
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await prefs.remove(key);
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}
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}
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@ -116,50 +104,41 @@ class GeoMetadataLookup {
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List<Map<String, dynamic>> _findMetadata(double latitude, double longitude, Map<String, dynamic> geoJson, double distanceThreshold) {
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final Position point = Position(longitude, latitude);
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List<Map<String, dynamic>> results = [];
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final List<Map<String, dynamic>> results = [];
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for (var feature in geoJson['features']) {
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final geometry = feature['geometry'];
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final properties = feature['properties'] ?? {};
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final metadata = properties['tags']?.cast<String, dynamic>() ?? {};
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metadata.removeWhere((key, value) => value == null);
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if (geometry['type'] == 'Polygon') {
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final polygon = Polygon(
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coordinates: (geometry['coordinates'] as List)
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.map((ring) => (ring as List)
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.map((p) => Position(p[0] as double, p[1] as double))
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.toList())
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.toList(),
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);
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if (booleanPointInPolygon(point, polygon)) {
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results.add({"type": "polygon", ...metadata});
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}
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}
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else if (geometry['type'] == 'LineString') {
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final line = LineString(
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coordinates: (geometry['coordinates'] as List)
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.map((p) => Position(p[0] as double, p[1] as double))
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.toList(),
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);
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if (_isPointNearLine(point, line, distanceThreshold)) {
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results.add({"type": "line", ...metadata});
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}
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final metadata = Map<String, dynamic>.from(feature['properties']['tags'] ?? {})..removeWhere((_, v) => v == null);
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switch (geometry['type']) {
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case 'Polygon':
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final polygon = Polygon(
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coordinates: (geometry['coordinates'] as List)
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.map((ring) => (ring as List)
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.map((p) => Position(p[0].toDouble(), p[1].toDouble()))
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.toList())
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.toList(),
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);
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if (booleanPointInPolygon(point, polygon)) results.add({"type": "polygon", ...metadata});
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break;
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case 'LineString':
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final line = LineString(
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coordinates: (geometry['coordinates'] as List)
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.map((p) => Position(p[0].toDouble(), p[1].toDouble()))
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.toList(),
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);
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if (_isPointNearLine(Point(coordinates: point), line, distanceThreshold)) results.add({"type": "line", ...metadata});
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break;
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}
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}
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return results;
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}
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bool _isPointNearLine(Position point, LineString line, double distanceThreshold) {
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for (var p1 in line.coordinates) {
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final double dist = distance.distance(
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LatLng(point.lat.toDouble(), point.lng.toDouble()),
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LatLng(p1.lat.toDouble(), p1.lng.toDouble()),
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);
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if (dist <= distanceThreshold) return true;
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bool _isPointNearLine(Point point, LineString line, double distanceThreshold) {
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for (final Position p in line.coordinates) {
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if (distance(point, Point(coordinates: p), Unit.meters) <= distanceThreshold) {
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return true;
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}
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}
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return false;
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}
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}
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}
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