// -*- mode: c++; c-basic-offset:4 -*-

// This file is part of libdap, A C++ implementation of the OPeNDAP Data

// Access Protocol.

// Copyright (c) 2002,2003 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.

// (c) COPYRIGHT URI/MIT 1994-1999

// Please read the full copyright statement in the file COPYRIGHT_URI.

//

// Authors:

//      jhrg,jimg       James Gallagher <jgallagher@gso.uri.edu>

// Implementation for the Error class.

#include "config.h"

#include <cstdio>

#include <cassert>

#include "Error.h"

#include "parser.h"

#include "InternalErr.h"

#include "debug.h"

using namespace std;

// Glue routines declared in Error.lex

extern void Error_switch_to_buffer(void *new_buffer);

extern void Error_delete_buffer(void * buffer);

extern void *Error_buffer(FILE *fp);

//extern void Errorrestart(FILE *yyin); // defined in Error.tab.c

extern int Errorparse(libdap::parser_arg *arg);

namespace libdap {

// There are two entries for 'cannot read file' because of an error made 

// when the message was first added to this class. 

static const char *err_messages[] = {

    "Undefined error",

    "Unknown error",

    "Internal error",

    "No such file",

    "No such variable",

    "Malformed expression",

    "No authorization",

    "Cannot read file",

    "Not Implemented",

    ""

};

/** Specializations of Error should use this to set the error code and

    message. */

Error::Error() : _error_code(undefined_error), _error_message("")

{}

/** Create an instance with a specific code and message string. This ctor

    provides a way to to use any code and string you'd like. The code can be

    one of the standard codes or it may be specific to your server. Thus a

    client which can tell it's dealing with a specific type of server can use

    the code accordingly. In general, clients simply show the error message

    to users or write it to a log file.

    @param ec The error code

    @param msg The error message string. */

Error::Error(ErrorCode ec, string msg)

        : _error_code(ec), _error_message(msg)

{}

/** Create an instance with a specific message. The error code is set to \c

    unknown_error.

    @param msg The error message.

    @see ErrorCode */

Error::Error(string msg)

        : _error_code(unknown_error), _error_message(msg)

{}

Error::Error(const Error &copy_from)

        : _error_code(copy_from._error_code),

        _error_message(copy_from._error_message)

{

}

Error::~Error()

{

}

Error &

Error::operator=(const Error &rhs)

{

    assert(OK());

    if (&rhs == this)  // are they identical?

        return *this;

    else {

        _error_code = rhs._error_code;

        _error_message = rhs._error_message;

        assert(this->OK());

        return *this;

    }

}

/** Use this function to determine whether an Error object is

    valid.  To be a valid, an Error object must either be: 1)

    empty or contain a message and a code.

    @brief Is the Error object valid?

    @return TRUE if the object is valid, FALSE otherwise. */

bool

Error::OK() const

{

    // The object is empty - users cannot make these, but this class can!

    bool empty = ((_error_code == undefined_error)

                  && (_error_message.empty()));

    // Just a message - the program part is null.

    bool message = ((_error_code != undefined_error)

                    && (!_error_message.empty()));

    DBG(cerr << "empty: " << empty << ", message: " << message << endl);

    return empty || message;

}

/** Given an input stream (FILE *) <tt>fp</tt>, parse an Error object from

    stream. Values for fields of the Error object are parsed and \c this is

    set accordingly. This is how a client program receives an error object

    from a server.

    @brief Parse an Error object.

    @param fp A valid file pointer to an input stream.

    @return TRUE if no error was detected, FALSE otherwise.  */

bool

Error::parse(FILE *fp)

{

    if (!fp)

        throw InternalErr(__FILE__, __LINE__, "Null input stream");

    void *buffer = Error_buffer(fp);

    Error_switch_to_buffer(buffer);

    parser_arg arg(this);

    bool status;

    try {

        status = Errorparse(&arg) == 0;

        Error_delete_buffer(buffer);

    }

    catch (Error &e) {

        Error_delete_buffer(buffer);

        throw InternalErr(__FILE__, __LINE__, e.get_error_message());

    }

    // STATUS is the result of the parser function; if a recoverable error

    // was found it will be true but arg.status() will be false.

    // I'm throwing an InternalErr here since Error objects are generated by

    // the core; they should always parse! 9/21/2000 jhrg

    if (!status || !arg.status())

        throw InternalErr(__FILE__, __LINE__, "Error parsing error object!");

    else

        return OK();  // Check object consistency

}

/** Creates a printable representation of the Error object. It is suitable

    for framing, and also for printing and sending over a network.

    The printed representation produced by this function can be parsed by the

    parse() member function. Thus parse and print form a symmetrical pair

    that can be used to send and receive an Error object over the network in

    a MIME document.

    @param out A pointer to the output stream on which the Error object is to

    be rendered. */

void

Error::print(FILE *out) const

{

    assert(OK());

    fprintf(out, "Error {\n") ;

    fprintf(out, "    code = %d;\n", static_cast<int>(_error_code)) ;

    // If the error message is wrapped in double quotes, print it, else, add

    // wrapping double quotes.

    if (*_error_message.begin() == '"' && *(_error_message.end() - 1) == '"')

        fprintf(out, "    message = %s;\n", _error_message.c_str()) ;

    else

        fprintf(out, "    message = \"%s\";\n", _error_message.c_str()) ;

    fprintf(out, "};\n") ;

}

/** Creates a printable representation of the Error object. It is suitable

    for framing, and also for printing and sending over a network.

    The printed representation produced by this function can be parsed by the

    parse() member function. Thus parse and print form a symmetrical pair

    that can be used to send and receive an Error object over the network in

    a MIME document.

    @param strm A reference to the output stream on which the Error object is to

    be rendered. */

void

Error::print(ostream &strm) const

{

    assert(OK());

    strm << "Error {\n" ;

    strm << "    code = " << static_cast<int>(_error_code) << ";\n" ;

    // If the error message is wrapped in double quotes, print it, else, add

    // wrapping double quotes.

    if (*_error_message.begin() == '"' && *(_error_message.end() - 1) == '"')

        strm << "    message = " << _error_message.c_str() << ";\n" ;

    else

        strm << "    message = \"" << _error_message.c_str() << "\";\n"  ;

    strm << "};\n" ;

}

/** Get the ErrorCode for this instance. */

ErrorCode

Error::get_error_code() const

{

    assert(OK());

    return _error_code;

}

/** Set the ErrorCode. If the current error message has not been set, use \e

    ec to set the error message. The resulting error message string is the

    same as the ErrorCode name. If \e ec is not within the range of values

    for an OPeNDAP ErrorCode, the error message is left unchanged.

    @param ec The new ErrorCode value. */

void

Error::set_error_code(ErrorCode ec)

{

    _error_code = ec;

    // Added check to make sure that err_messages is not accessed beyond its

    // bounds. 02/02/04 jhrg

    if (_error_message.empty()

        && ec > undefined_error && ec <= cannot_read_file) {

        _error_message = err_messages[ec - undefined_error];

    }

    else {

        _error_message = err_messages[0];

    }

}

/** Return the current error message. */

string

Error::get_error_message() const

{

    assert(OK());

    return string(_error_message);

}

/** Set the error message. */

void

Error::set_error_message(string msg)

{

    _error_message = msg;

}

} // namespace libdap