| #region Apache License |
| // |
| // Licensed to the Apache Software Foundation (ASF) under one or more |
| // contributor license agreements. See the NOTICE file distributed with |
| // this work for additional information regarding copyright ownership. |
| // The ASF licenses this file to you under the Apache License, Version 2.0 |
| // (the "License"); you may not use this file except in compliance with |
| // the License. You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| // |
| #endregion |
| |
| using System; |
| using System.Collections.Generic; |
| |
| namespace log4net.Repository.Hierarchy |
| { |
| /// <summary> |
| /// Used internally to accelerate hash table searches. |
| /// </summary> |
| /// <remarks> |
| /// <para> |
| /// Internal class used to improve performance of |
| /// string keyed hashtables. |
| /// </para> |
| /// <para> |
| /// The hashcode of the string is cached for reuse. |
| /// The string is stored as an interned value. |
| /// When comparing two <see cref="LoggerKey"/> objects for equality |
| /// the reference equality of the interned strings is compared. |
| /// </para> |
| /// </remarks> |
| /// <author>Nicko Cadell</author> |
| /// <author>Gert Driesen</author> |
| internal readonly struct LoggerKey |
| { |
| /// <summary> |
| /// Construct key with string name |
| /// </summary> |
| /// <remarks> |
| /// <para> |
| /// Initializes a new instance of the <see cref="LoggerKey" /> class |
| /// with the specified name. |
| /// </para> |
| /// <para> |
| /// Stores the hashcode of the string and interns |
| /// the string key to optimize comparisons. |
| /// </para> |
| /// <note> |
| /// The Compact Framework 1.0 the <see cref="String.Intern"/> |
| /// method does not work. On the Compact Framework |
| /// the string keys are not interned nor are they |
| /// compared by reference. |
| /// </note> |
| /// </remarks> |
| /// <param name="name">The name of the logger.</param> |
| internal LoggerKey(string name) |
| { |
| m_name = string.Intern(name); |
| m_hashCache = name.GetHashCode(); |
| } |
| |
| /// <summary> |
| /// Returns a hash code for the current instance. |
| /// </summary> |
| /// <returns>A hash code for the current instance.</returns> |
| /// <remarks> |
| /// <para> |
| /// Returns the cached hashcode. |
| /// </para> |
| /// </remarks> |
| public override int GetHashCode() |
| { |
| return m_hashCache; |
| } |
| |
| private readonly string m_name; |
| private readonly int m_hashCache; |
| |
| public static Comparer ComparerInstance { get; } = new(); |
| |
| public sealed class Comparer : IEqualityComparer<LoggerKey> |
| { |
| public bool Equals(LoggerKey x, LoggerKey y) |
| { |
| return x.m_hashCache == y.m_hashCache && x.m_name == y.m_name; |
| } |
| |
| public int GetHashCode(LoggerKey obj) => obj.m_hashCache; |
| } |
| } |
| } |