BESRequestHandlerList.cc

// BESRequestHandlerList.cc
 
// This file is part of bes, A C++ back-end server implementation framework
// for the OPeNDAP Data Access Protocol.
 
// Copyright (c) 2004-2009 University Corporation for Atmospheric Research
// Author: Patrick West <pwest@ucar.edu> and Jose Garcia <jgarcia@ucar.edu>
//
// 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 University Corporation for Atmospheric Research at
// 3080 Center Green Drive, Boulder, CO 80301
 
// (c) COPYRIGHT University Corporation for Atmospheric Research 2004-2005
// Please read the full copyright statement in the file COPYRIGHT_UCAR.
//
// Authors:
//      pwest       Patrick West <pwest@ucar.edu>
//      jgarcia     Jose Garcia <jgarcia@ucar.edu>
 
#include "config.h"
#include <mutex>
 
#include "BESLog.h"
#include "BESRequestHandlerList.h"
#include "BESRequestHandler.h"
#include "BESInternalError.h"
 
using std::endl;
using std::ostream;
using std::string;
 
BESRequestHandlerList *BESRequestHandlerList::d_instance = nullptr;
static std::once_flag d_euc_init_once;
 
BESRequestHandlerList::BESRequestHandlerList() {}
 
BESRequestHandlerList::~BESRequestHandlerList() {}
 
bool BESRequestHandlerList::add_handler(const string &handler_name, BESRequestHandler *handler_object)
{
    std::lock_guard<std::recursive_mutex> lock_me(d_cache_lock_mutex);
 
    if (find_handler(handler_name) == 0) {
        _handler_list[handler_name] = handler_object;
        return true;
    }
    return false;
}
 
BESRequestHandler *
BESRequestHandlerList::remove_handler(const string &handler_name)
{
    std::lock_guard<std::recursive_mutex> lock_me(d_cache_lock_mutex);
 
    BESRequestHandler *ret = 0;
    BESRequestHandlerList::Handler_iter i;
    i = _handler_list.find(handler_name);
    if (i != _handler_list.end()) {
        ret = (*i).second;
        _handler_list.erase(i);
    }
    return ret;
}
 
BESRequestHandler *
BESRequestHandlerList::find_handler(const string &handler_name)
{
    std::lock_guard<std::recursive_mutex> lock_me(d_cache_lock_mutex);
 
    BESRequestHandlerList::Handler_citer i;
    i = _handler_list.find(handler_name);
    if (i != _handler_list.end()) {
        return (*i).second;
    }
    return 0;
}
 
BESRequestHandlerList::Handler_citer BESRequestHandlerList::get_first_handler()
{
    std::lock_guard<std::recursive_mutex> lock_me(d_cache_lock_mutex);
 
    return _handler_list.begin();
}
 
BESRequestHandlerList::Handler_citer BESRequestHandlerList::get_last_handler()
{
    std::lock_guard<std::recursive_mutex> lock_me(d_cache_lock_mutex);
 
    return _handler_list.end();
}
 
string BESRequestHandlerList::get_handler_names()
{
    std::lock_guard<std::recursive_mutex> lock_me(d_cache_lock_mutex);
 
    string ret = "";
    bool first_name = true;
    BESRequestHandlerList::Handler_citer i = _handler_list.begin();
    for (; i != _handler_list.end(); i++) {
        if (!first_name) ret += ", ";
        ret += (*i).first;
        first_name = false;
    }
    return ret;
}
 
void BESRequestHandlerList::execute_each(BESDataHandlerInterface &dhi)
{
    std::lock_guard<std::recursive_mutex> lock_me(d_cache_lock_mutex);
 
    dhi.first_container();
    while (dhi.container) {
        execute_current(dhi);
        dhi.next_container();
    }
}
 
void BESRequestHandlerList::execute_all(BESDataHandlerInterface &dhi)
{
    std::lock_guard<std::recursive_mutex> lock_me(d_cache_lock_mutex);
 
    BESRequestHandlerList::Handler_citer i = get_first_handler();
    BESRequestHandlerList::Handler_citer ie = get_last_handler();
    for (; i != ie; i++) {
        BESRequestHandler *rh = (*i).second;
        p_request_handler_method p = rh->find_method(dhi.action);
        if (p) {
            p(dhi);
        }
    }
}
 
#if 0
void BESRequestHandlerList::execute_once(BESDataHandlerInterface &dhi)
{
    dhi.first_container();
    execute_current(dhi);
}
#endif
 
void BESRequestHandlerList::execute_current(BESDataHandlerInterface &dhi)
{
    std::lock_guard<std::recursive_mutex> lock_me(d_cache_lock_mutex);
 
    if (dhi.container) {
        // Patrick's comment: This needs to happen here, but really should be done
        // in the get_container_type method in the container class if it
        // needs to happen.
        //
        // This call will, for BESFileContainer, decompress and cache compressed files,
        // changing their extensions from, e.g., '.gz' to '.h5' and enabling the
        // get_container_type() method to function correctly. jhrg 5/31/18
        dhi.container->access();
 
        // Given the kind of thing in the DHI's container (netcdf file, ...) find the
        // RequestHandler that understands that and then find the method in that handler
        // that can process the DHI's action.
        BESRequestHandler *rh = find_handler((dhi.container->get_container_type()));
        if (!rh)
            throw BESInternalError(string("The data handler '") + dhi.container->get_container_type() + "' does not exist",
                __FILE__, __LINE__);
 
        p_request_handler_method request_handler_method = rh->find_method(dhi.action);
        if (!request_handler_method) {
            throw BESInternalError(string("Request handler for '") + dhi.container->get_container_type()
                + "' does not handle the response type '" + dhi.action + "'", __FILE__, __LINE__);
        }
 
        VERBOSE("Found handler '" << rh->get_name() << "' for item '" << dhi.container->get_symbolic_name() << "'." << endl);
 
        request_handler_method(dhi); // This is where the request handler method is called
    }
}
 
void BESRequestHandlerList::dump(ostream &strm) const
{
    std::lock_guard<std::recursive_mutex> lock_me(d_cache_lock_mutex);
 
    strm << BESIndent::LMarg << "BESRequestHandlerList::dump - (" << (void *) this << ")" << endl;
    BESIndent::Indent();
    if (_handler_list.size()) {
        strm << BESIndent::LMarg << "registered handlers:" << endl;
        BESIndent::Indent();
        BESRequestHandlerList::Handler_citer i = _handler_list.begin();
        BESRequestHandlerList::Handler_citer ie = _handler_list.end();
        for (; i != ie; i++) {
            BESRequestHandler *rh = (*i).second;
            rh->dump(strm);
        }
        BESIndent::UnIndent();
    }
    else {
        strm << BESIndent::LMarg << "registered handlers: none" << endl;
    }
    BESIndent::UnIndent();
}
 
BESRequestHandlerList *
BESRequestHandlerList::TheList()
{
    std::call_once(d_euc_init_once,BESRequestHandlerList::initialize_instance);
    return d_instance;
}
 
void BESRequestHandlerList::initialize_instance() {
    d_instance = new BESRequestHandlerList;
#ifdef HAVE_ATEXIT
    atexit(delete_instance);
#endif
}
 
void BESRequestHandlerList::delete_instance() {
    delete d_instance;
    d_instance = 0;
}