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(possible) optimization when locating entries

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Thibault Deckers 2020-07-18 23:55:01 +09:00
parent 80a591ca82
commit de3528baab
1 changed files with 21 additions and 2 deletions
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23
lib/model/source/location.dart
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@ -4,6 +4,7 @@ import 'package:aves/model/metadata_db.dart';
import 'package:aves/model/source/collection_source.dart';
import 'package:collection/collection.dart';
import 'package:flutter/foundation.dart';
import 'package:tuple/tuple.dart';
mixin LocationMixin on SourceBase {
static const _commitCountThreshold = 50;
@ -24,16 +25,34 @@ mixin LocationMixin on SourceBase {
Future<void> locateEntries() async {
// final stopwatch = Stopwatch()..start();
final todo = rawEntries.where((entry) => entry.hasGps && !entry.isLocated).toList();
final byLocated = groupBy<ImageEntry, bool>(rawEntries.where((entry) => entry.hasGps), (entry) => entry.isLocated);
final todo = byLocated[false] ?? [];
if (todo.isEmpty) return;
// cache known locations to avoid querying the geocoder unless necessary
// measuring the time it takes to process ~3000 coordinates (with ~10% of duplicates)
// does not clearly show whether it is an actual optimization,
// as results vary wildly (durations in "min:sec"):
// - with no cache: 06:17, 08:36, 08:34
// - with cache: 08:28, 05:42, 08:03, 05:58
// anyway, in theory it should help!
final knownLocations = <Tuple2<double, double>, AddressDetails>{};
byLocated[true]?.forEach((entry) => knownLocations.putIfAbsent(entry.latLng, () => entry.addressDetails));
var progressDone = 0;
final progressTotal = todo.length;
setProgress(done: progressDone, total: progressTotal);
final newAddresses = <AddressDetails>[];
await Future.forEach<ImageEntry>(todo, (entry) async {
await entry.locate(background: true);
if (knownLocations.containsKey(entry.latLng)) {
entry.addressDetails = knownLocations[entry.latLng]?.copyWith(contentId: entry.contentId);
} else {
await entry.locate(background: true);
// it is intended to insert `null` if the geocoder failed,
// so that we skip geocoding of following entries with the same coordinates
knownLocations[entry.latLng] = entry.addressDetails;
}
if (entry.isLocated) {
newAddresses.add(entry.addressDetails);
if (newAddresses.length >= _commitCountThreshold) {