blob: ac0b311bf82d52e2151169a87a2342fbbaddf08e [file] [log] [blame] [edit]
// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
Map<Key, dynamic> _cache = <Key, dynamic>{};
const int _maxSize = 10;
T cache<T>(Key key, T Function() getter) {
T result;
if (_cache[key] != null) {
result = _cache[key] as T;
_cache.remove(key);
} else {
if (_cache.length == _maxSize) {
_cache.remove(_cache.keys.first);
}
result = getter();
assert(result is! Function);
}
_cache[key] = result;
return result;
}
abstract class Key {
Key(this._value);
final dynamic _value;
@override
bool operator ==(Object other) {
if (identical(this, other)) {
return true;
}
if (runtimeType != other.runtimeType) {
return false;
}
return other is Key && other._value == _value;
}
@override
int get hashCode => runtimeType.hashCode ^ _value.hashCode;
@override
String toString() => '$runtimeType($_value)';
}