AISMerge.cc

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// -*- mode: c++; c-basic-offset:4 -*-
 
// This file is part of libdap, A C++ implementation of the OPeNDAP Data
// Access Protocol.
 
// Copyright (c) 2003 OPeNDAP, Inc.
// Author: James Gallagher <jgallagher@opendap.org>
//         Dan Holloway <dan@hollywood.gso.uri.edu>
//         Reza Nekovei <reza@intcomm.net>
//
// 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.
 
#include "config.h"
 
#include <cstdio>
#include <fstream>
 
#include "AISExceptions.h"
#include "AISMerge.h"
#include "Response.h"
 
namespace libdap {

Response *AISMerge::get_ais_resource(const string &res) {
    if (res.find("http:") == 0 || res.find("file:") == 0 || res.find("https:") == 0) {
        return d_http.fetch_url(res);
    } else {
        FILE *s = fopen(res.c_str(), "r");
        if (!s)
            throw Error("I could not open local AIS resource '" + res + "'.");
        return new Response(s, 0);
    }
}

void AISMerge::merge(const string &primary, DAS &das) {
    if (!d_ais_db.has_resource(primary))
        return;
 
    try {
        ResourceVector rv = d_ais_db.get_resource(primary);
 
        for (ResourceVectorIter i = rv.begin(); i != rv.end(); ++i) {
            Response *ais_resource = get_ais_resource(i->get_url());
            switch (i->get_rule()) {
            case Resource::overwrite:
                das.parse(ais_resource->get_stream());
                break;
            case Resource::replace:
                das.erase();
                das.parse(ais_resource->get_stream());
                break;
            case Resource::fallback:
                if (das.get_size() == 0)
                    das.parse(ais_resource->get_stream());
                break;
            }
            delete ais_resource;
            ais_resource = 0;
        }
    } catch (NoSuchPrimaryResource &e) {
        throw InternalErr(string("I caught a 'NoSuchPrimaryResource' exception, it said:\n") + e.get_error_message() +
                          string("\n"));
    }
}
 
} // namespace libdap