112 lines
2.9 KiB
C#
112 lines
2.9 KiB
C#
// Copyright 2019 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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using System;
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using System.Collections;
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using System.Collections.Generic;
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using System.Linq;
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namespace Google.Android.AppBundle.Editor.Internal.Utils
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{
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/// <summary>
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/// An empty <see cref="IDictionary"/> that cannot be added to.
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/// </summary>
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public class EmptyDictionary<TKey, TValue> : IDictionary<TKey, TValue>
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{
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private readonly EmptyCollection<TKey> EmptyKeys = new EmptyCollection<TKey>();
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private readonly EmptyCollection<TValue> EmptyValues = new EmptyCollection<TValue>();
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public int Count
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{
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get { return 0; }
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}
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public bool IsReadOnly
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{
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get { return true; }
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}
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public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator()
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{
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return Enumerable.Empty<KeyValuePair<TKey, TValue>>().GetEnumerator();
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}
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IEnumerator IEnumerable.GetEnumerator()
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{
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return GetEnumerator();
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}
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public ICollection<TKey> Keys
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{
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get { return EmptyKeys; }
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}
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public ICollection<TValue> Values
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{
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get { return EmptyValues; }
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}
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public bool Contains(KeyValuePair<TKey, TValue> item)
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{
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return false;
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}
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public bool ContainsKey(TKey key)
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{
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return false;
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}
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public bool TryGetValue(TKey key, out TValue value)
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{
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value = default(TValue);
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return false;
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}
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public TValue this[TKey key]
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{
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get { throw new KeyNotFoundException(); }
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set { throw new NotSupportedException(); }
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}
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public void Add(TKey key, TValue value)
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{
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throw new NotSupportedException();
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}
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public bool Remove(TKey key)
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{
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throw new NotSupportedException();
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}
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public void Add(KeyValuePair<TKey, TValue> item)
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{
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throw new NotSupportedException();
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}
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public bool Remove(KeyValuePair<TKey, TValue> item)
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{
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throw new NotSupportedException();
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}
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public void Clear()
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{
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// No-op.
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}
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public void CopyTo(KeyValuePair<TKey, TValue>[] array, int arrayIndex)
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{
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// No-op.
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}
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}
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} |