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