CurlHandlePool.h

// -*- mode: c++; c-basic-offset:4 -*-
 
// This file is part of the BES
 
// Copyright (c) 2018 OPeNDAP, Inc.
// Author: James Gallagher<jgallagher@opendap.org>
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
//
// You can contact OPeNDAP, Inc. at PO Box 112, Saunderstown, RI. 02874-0112.
 
#ifndef _HandlePool_h
#define _HandlePool_h 1
 
#include <memory>
#include <string>
#include <vector>
#include <mutex>
 
#include <pthread.h>
 
#include <curl/curl.h>
 
#include "url_impl.h"
 
namespace dmrpp {
 
class Chunk;
 
class dmrpp_easy_handle {
    bool d_in_use;      
    std::shared_ptr<http::url> d_url;  
    Chunk *d_chunk;     
    char d_errbuf[CURL_ERROR_SIZE]; 
    CURL *d_handle;     
    curl_slist *d_request_headers; 
 
    friend class CurlHandlePool;
 
public:
    dmrpp_easy_handle();
 
    ~dmrpp_easy_handle();
 
    void read_data();
};
 
class CurlHandlePool {
private:
    unsigned int d_max_easy_handles;
    std::vector<dmrpp_easy_handle *> d_easy_handles;
    std::recursive_mutex d_get_easy_handle_mutex;
 
    friend class Lock;
 
public:
    CurlHandlePool() = delete;
    explicit CurlHandlePool(unsigned int max_handles);
 
    ~CurlHandlePool()
    {
        for (auto i = d_easy_handles.begin(), e = d_easy_handles.end(); i != e; ++i) {
            delete *i;
        }
    }
 
    unsigned int get_max_handles() const
    { return d_max_easy_handles; }
 
    unsigned int get_handles_available() const
    {
        unsigned int n = 0;
        for (auto i = d_easy_handles.begin(), e = d_easy_handles.end(); i != e; ++i) {
            if (!(*i)->d_in_use) {
                n++;
 
            }
        }
        return n;
    }
 
    dmrpp_easy_handle *get_easy_handle(Chunk *chunk);
 
    void release_handle(dmrpp_easy_handle *h);
 
    void release_handle(Chunk *chunk);
 
    void release_all_handles();
};
 
} // namespace dmrpp
 
#endif // _HandlePool_h