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114 lines
2.9 KiB
C++
114 lines
2.9 KiB
C++
/* -------------------------------------------------------------------------- */
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/* Copyright 2002-2024, OpenNebula Project, OpenNebula Systems */
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/* */
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/* Licensed under the Apache License, Version 2.0 (the "License"); you may */
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/* not use this file except in compliance with the License. You may obtain */
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/* a copy of the License at */
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/* */
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/* http://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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/* -------------------------------------------------------------------------- */
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#ifndef REQUEST_MANAGER_CONNECTION_H_
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#define REQUEST_MANAGER_CONNECTION_H_
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#include "RequestManager.h"
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#include <condition_variable>
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/**
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* The connection manager class synchronizes the connection and manager threads
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*/
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class ConnectionManager
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{
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public:
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ConnectionManager(int mc)
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: connections(0)
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, max_connections(mc)
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, end(false)
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{
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}
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~ConnectionManager() = default;
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/**
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* Increments number of active connections
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*/
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int add()
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{
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std::lock_guard<std::mutex> lock(_mutex);
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return ++connections;
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}
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/**
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* Decrements number of active connections and signals management thread
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*/
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void del()
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{
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std::lock_guard<std::mutex> lock(_mutex);
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--connections;
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cond.notify_one();
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}
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/**
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* Waits for active connections to be under the max_connection threshold
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*/
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void wait()
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{
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std::unique_lock<std::mutex> lock(_mutex);
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if (end)
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{
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return;
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}
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cond.wait(lock, [&]
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{
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return (connections < max_connections) || end;
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});
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}
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/**
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* Interrupts and prevents wait() operations
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*/
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void terminate()
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{
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std::lock_guard<std::mutex> lock(_mutex);
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end = true;
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cond.notify_one();
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}
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private:
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/**
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* Synchronization for connection threads and listener thread
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*/
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std::mutex _mutex;
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std::condition_variable cond;
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/**
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* Number of active connections
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*/
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int connections;
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/**
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* Max number of active connections
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*/
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int max_connections;
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/**
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* Terminate wait
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*/
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std::atomic<bool> end;
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};
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#endif
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