AISMerge.cc

// -*- 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 "AISMerge.h"
#include "AISExceptions.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 {
#if 0
        ifstream s(res);
#endif
        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