261 lines
9.5 KiB
C#
261 lines
9.5 KiB
C#
//Copyright (c) 2007-2008 Henrik Schr鰀er, Oliver Kofoed Pedersen
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//Permission is hereby granted, free of charge, to any person
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//obtaining a copy of this software and associated documentation
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//files (the "Software"), to deal in the Software without
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//restriction, including without limitation the rights to use,
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//copy, modify, merge, publish, distribute, sublicense, and/or sell
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//copies of the Software, and to permit persons to whom the
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//Software is furnished to do so, subject to the following
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//conditions:
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//The above copyright notice and this permission notice shall be
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//included in all copies or substantial portions of the Software.
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//THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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//EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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//OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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//NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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//HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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//WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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//FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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//OTHER DEALINGS IN THE SOFTWARE.
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using System;
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using System.Collections.Generic;
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using System.Text;
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namespace CYQ.Data.Cache
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{
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internal delegate T UseSocket<T>(MSocket socket);
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internal delegate void UseSocket(MSocket socket);
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/// <summary>
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/// The ServerPool encapsulates a collection of memcached servers and the associated SocketPool objects.
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/// This class contains the server-selection logic, and contains methods for executing a block of code on
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/// a socket from the server corresponding to a given key.
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/// </summary>
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internal class ServerPool
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{
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//用于验证权限的委托事件。
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internal delegate bool AuthDelegate(MSocket socket);
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internal event AuthDelegate OnAuthEvent;
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private static LogAdapter logger = LogAdapter.GetLogger(typeof(ServerPool));
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internal CacheType serverType = CacheType.MemCache;
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/// <summary>
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/// 备份的Socket池，如果某主机挂了，在配置了备份的情况下，会由备份Socket池提供服务。
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/// </summary>
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internal ServerPool serverPoolBak;
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//Expose the socket pools.
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private SocketPool[] hostList;
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internal SocketPool[] HostList { get { return hostList; } }
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private Dictionary<uint, SocketPool> hostDictionary;
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private uint[] hostKeys;
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//Internal configuration properties
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private int sendReceiveTimeout = 5000;
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private int connectTimeout = 3000;
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private uint maxPoolSize = 10;
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private uint minPoolSize = 1;
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private TimeSpan socketRecycleAge = TimeSpan.FromMinutes(30);
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internal int SendReceiveTimeout { get { return sendReceiveTimeout; } set { sendReceiveTimeout = value; } }
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internal int ConnectTimeout { get { return connectTimeout; } set { connectTimeout = value; } }
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internal uint MaxPoolSize { get { return maxPoolSize; } set { maxPoolSize = value; } }
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internal uint MinPoolSize { get { return minPoolSize; } set { minPoolSize = value; } }
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internal TimeSpan SocketRecycleAge { get { return socketRecycleAge; } set { socketRecycleAge = value; } }
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//private string clientName;
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/// <summary>
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/// Internal constructor. This method takes the array of hosts and sets up an internal list of socketpools.
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/// </summary>
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internal ServerPool(string[] hosts, CacheType serverType)
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{
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this.serverType = serverType;//服务的缓存类型（为了支持Redis的密码功能，在这里增加点依赖扩展。）
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hostDictionary = new Dictionary<uint, SocketPool>();
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List<SocketPool> pools = new List<SocketPool>();
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List<uint> keys = new List<uint>();
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foreach (string hostItem in hosts)//遍历每一台主机。
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{
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if (string.IsNullOrEmpty(hostItem)) { continue; }
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string[] items = hostItem.Split('-');
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string pwd = "";
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string host = items[0].Trim(); ;
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if (items.Length > 1)
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{
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pwd = items[1].Trim();
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}
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//Create pool
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SocketPool pool = new SocketPool(this, host);
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pool.OnAfterSocketCreateEvent += new SocketPool.OnAfterSocketCreateDelegate(pool_OnAfterSocketCreateEvent);
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if (!string.IsNullOrEmpty(pwd))
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{
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pool.password = pwd;
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}
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//Create 250 keys for this pool, store each key in the hostDictionary, as well as in the list of keys.
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for (int i = 0; i < 250; i++)
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{
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uint key = BitConverter.ToUInt32(new ModifiedFNV1_32().ComputeHash(Encoding.UTF8.GetBytes(host + "-" + i)), 0);
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if (!hostDictionary.ContainsKey(key))
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{
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hostDictionary[key] = pool;
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keys.Add(key);
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}
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}
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pools.Add(pool);
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}
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//Hostlist should contain the list of all pools that has been created.
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hostList = pools.ToArray();
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//Hostkeys should contain the list of all key for all pools that have been created.
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//This array forms the server key continuum that we use to lookup which server a
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//given item key hash should be assigned to.
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keys.Sort();
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hostKeys = keys.ToArray();
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}
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bool pool_OnAfterSocketCreateEvent(MSocket socket)
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{
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if (OnAuthEvent != null)
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{
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return OnAuthEvent(socket);
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}
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return true;
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}
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/// <summary>
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/// Given an item key hash, this method returns the socketpool which is closest on the server key continuum.
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/// </summary>
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internal SocketPool GetSocketPool(uint hash)
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{
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//Quick return if we only have one host.
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if (hostList.Length == 1)
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{
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return hostList[0];
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}
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//New "ketama" host selection.
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int i = Array.BinarySearch(hostKeys, hash);
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//If not exact match...
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if (i < 0)
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{
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//Get the index of the first item bigger than the one searched for.
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i = ~i;
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//If i is bigger than the last index, it was bigger than the last item = use the first item.
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if (i >= hostKeys.Length)
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{
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i = 0;
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}
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}
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return hostDictionary[hostKeys[i]];
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}
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internal SocketPool GetSocketPool(string host)
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{
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return Array.Find(HostList, delegate(SocketPool socketPool) { return socketPool.Host == host; });
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}
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/// <summary>
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/// This method executes the given delegate on a socket from the server that corresponds to the given hash.
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/// If anything causes an error, the given defaultValue will be returned instead.
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/// This method takes care of disposing the socket properly once the delegate has executed.
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/// </summary>
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internal T Execute<T>(uint hash, T defaultValue, UseSocket<T> use)
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{
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SocketPool pool = GetSocketPool(hash);
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if (pool.socketPoolBak == null && serverPoolBak != null)
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{
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//为主Socket池挂接备份的Socket池
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pool.socketPoolBak = serverPoolBak.GetSocketPool(hash);
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}
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return Execute(pool, defaultValue, use);
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}
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internal T Execute<T>(SocketPool pool, T defaultValue, UseSocket<T> use)
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{
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MSocket sock = null;
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try
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{
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//Acquire a socket
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sock = pool.Acquire();
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//Use the socket as a parameter to the delegate and return its result.
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if (sock != null)
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{
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return use(sock);
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}
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}
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catch (Exception e)
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{
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logger.Error("Error in Execute<T>: " + pool.Host, e);
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//Socket is probably broken
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if (sock != null)
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{
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sock.Close();
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}
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}
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finally
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{
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if (sock != null)
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{
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sock.Dispose();
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}
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}
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return defaultValue;
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}
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internal void Execute(SocketPool pool, UseSocket use)
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{
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MSocket sock = null;
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try
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{
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//Acquire a socket
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sock = pool.Acquire();
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//Use the socket as a parameter to the delegate and return its result.
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if (sock != null)
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{
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use(sock);
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}
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}
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catch (Exception e)
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{
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logger.Error("Error in Execute: " + pool.Host, e);
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//Socket is probably broken
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if (sock != null)
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{
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sock.Close();
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}
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}
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finally
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{
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if (sock != null)
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{
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sock.Dispose();
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}
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}
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}
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/// <summary>
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/// This method executes the given delegate on all servers.
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/// </summary>
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internal void ExecuteAll(UseSocket use)
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{
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foreach (SocketPool socketPool in hostList)
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{
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Execute(socketPool, use);
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}
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}
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}
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} |