D4ParserSax2.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) 2012 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.
 
#include "config.h"
 
// #define DODS_DEBUG 1
 
#include <iostream>
#include <sstream>
 
#include <cassert>
#include <cstdarg>
#include <cstring>
 
#include <libxml2/libxml/parserInternals.h>
 
#include "DMR.h"
 
#include "Array.h"
#include "BaseType.h"
#include "D4Attributes.h"
#include "D4BaseTypeFactory.h"
#include "D4Enum.h"
#include "D4Group.h"
#include "D4Maps.h"
 
#include "D4ParserSax2.h"
#include "DapXmlNamespaces.h"
 
#include "debug.h"
#include "util.h"
 
namespace libdap {
 
static const char *states[] = {"parser_start",
 
                               "inside_dataset",
 
                               // inside_group is the state just after parsing the start of a Group
                               // element.
                               "inside_group",
 
                               "inside_attribute_container", "inside_attribute", "inside_attribute_value",
                               "inside_other_xml_attribute",
 
                               "inside_enum_def", "inside_enum_const",
 
                               "inside_dim_def",
 
                               // This covers Byte, ..., Url, Opaque
                               "inside_simple_type",
 
                               // "inside_array",
                               "inside_dim", "inside_map",
 
                               "inside_constructor",
 
                               "not_dap4_element",
 
                               "parser_unknown", "parser_error", "parser_fatal_error",
 
                               "parser_end"};
 
static bool is_not(const char *name, const char *tag) { return strcmp(name, tag) != 0; }

D4EnumDef *D4ParserSax2::enum_def() {
    if (!d_enum_def)
        d_enum_def = new D4EnumDef;
 
    return d_enum_def;
}

D4Dimension *D4ParserSax2::dim_def() {
    if (!d_dim_def)
        d_dim_def = new D4Dimension;
 
    return d_dim_def;
}

void D4ParserSax2::transfer_xml_attrs(const xmlChar **attributes, int nb_attributes) {
    if (!xml_attrs.empty())
        xml_attrs.clear(); // erase old attributes
 
    // Make a value using the attribute name and the prefix, namespace URI
    // and the value. The prefix might be null.
    unsigned int index = 0;
    for (int i = 0; i < nb_attributes; ++i, index += 5) {
        xml_attrs.insert(map<string, XMLAttribute>::value_type(string((const char *)attributes[index]),
                                                               XMLAttribute(attributes + index + 1)));
 
        DBG(cerr << "XML Attribute '" << (const char *)attributes[index]
                 << "': " << xml_attrs[(const char *)attributes[index]].value << endl);
    }
}

void D4ParserSax2::transfer_xml_ns(const xmlChar **namespaces, int nb_namespaces) {
    // make a value with the prefix and namespace URI. The prefix might be null.
    for (int i = 0; i < nb_namespaces; ++i) {
        namespace_table.insert(map<string, string>::value_type(
            namespaces[i * 2] != 0 ? (const char *)namespaces[i * 2] : "", (const char *)namespaces[i * 2 + 1]));
    }
}

bool D4ParserSax2::check_required_attribute(const string &attr) {
    if (xml_attrs.find(attr) == xml_attrs.end()) {
        dmr_error(this, "Required attribute '%s' not found.", attr.c_str());
        return false;
    } else
        return true;
}

bool D4ParserSax2::check_attribute(const string &attr) { return (xml_attrs.find(attr) != xml_attrs.end()); }
 
bool D4ParserSax2::process_dimension_def(const char *name, const xmlChar **attrs, int nb_attributes) {
    if (is_not(name, "Dimension"))
        return false;
 
    transfer_xml_attrs(attrs, nb_attributes);
 
    if (!(check_required_attribute("name") && check_required_attribute("size"))) {
        dmr_error(this, "The required attribute 'name' or 'size' was missing from a Dimension element.");
        return false;
    }
 
    // This getter (dim_def) allocates a new object if needed.
    dim_def()->set_name(xml_attrs["name"].value);
    try {
        dim_def()->set_size(xml_attrs["size"].value);
    } catch (Error &e) {
        dmr_error(this, "%s", e.get_error_message().c_str());
        return false;
    }
 
    return true;
}

bool D4ParserSax2::process_dimension(const char *name, const xmlChar **attrs, int nb_attributes) {
    if (is_not(name, "Dim"))
        return false;
 
    transfer_xml_attrs(attrs, nb_attributes);
 
    if (check_attribute("size") && check_attribute("name")) {
        dmr_error(this, "Only one of 'size' and 'name' are allowed in a Dim element, but both were used.");
        return false;
    }
    if (!(check_attribute("size") || check_attribute("name"))) {
        dmr_error(this, "Either 'size' or 'name' must be used in a Dim element.");
        return false;
    }
 
    if (!top_basetype()->is_vector_type()) {
        // Make the top BaseType* an array
        BaseType *b = top_basetype();
        pop_basetype();
 
        Array *a = static_cast<Array *>(dmr()->factory()->NewVariable(dods_array_c, b->name()));
        a->set_is_dap4(true);
        a->add_var_nocopy(b);
        a->set_attributes_nocopy(b->attributes());
        // trick: instead of popping b's attributes, copying them and then pushing
        // a's copy, just move the pointer (but make sure there's only one object that
        // references that pointer).
        b->set_attributes_nocopy(0);
 
        push_basetype(a);
    }
 
    assert(top_basetype()->is_vector_type());
 
    Array *a = static_cast<Array *>(top_basetype());
    if (check_attribute("size")) {
 
        a->append_dim_ll(strtoll(xml_attrs["size"].value.c_str(), nullptr, 10));
#if 0
        a->append_dim(atoi(xml_attrs["size"].value.c_str())); // low budget code for now. jhrg 8/20/13
#endif
        return true;
    } else if (check_attribute("name")) {
        string name = xml_attrs["name"].value;
 
        D4Dimension *dim = 0;
        if (name[0] == '/') // lookup the Dimension in the root group
            dim = dmr()->root()->find_dim(name);
        else // get enclosing Group and lookup Dimension there
            dim = top_group()->find_dim(name);
 
        if (!dim)
            throw Error("The dimension '" + name + "' was not found while parsing the variable '" + a->name() + "'.");
        a->append_dim(dim);
        return true;
    }
 
    return false;
}
 
bool D4ParserSax2::process_map(const char *name, const xmlChar **attrs, int nb_attributes) {
    if (is_not(name, "Map"))
        return false;
 
    transfer_xml_attrs(attrs, nb_attributes);
 
    if (!check_attribute("name")) {
        dmr_error(this, "The 'name' attribute must be used in a Map element.");
        return false;
    }
 
    if (!top_basetype()->is_vector_type()) {
        // Make the top BaseType* an array
        BaseType *b = top_basetype();
        pop_basetype();
 
        Array *a = static_cast<Array *>(dmr()->factory()->NewVariable(dods_array_c, b->name()));
        a->set_is_dap4(true);
        a->add_var_nocopy(b);
        a->set_attributes_nocopy(b->attributes());
        // trick: instead of popping b's attributes, copying them and then pushing
        // a's copy, just move the pointer (but make sure there's only one object that
        // references that pointer).
        b->set_attributes_nocopy(0);
 
        push_basetype(a);
    }
 
    assert(top_basetype()->is_vector_type());
 
    Array *a = static_cast<Array *>(top_basetype());
 
    string map_name = xml_attrs["name"].value;
    if (xml_attrs["name"].value[0] != '/')
        map_name = top_group()->FQN() + map_name;
 
    Array *map_source = 0; // The array variable that holds the data for the Map
 
    if (map_name[0] == '/') // lookup the Map in the root group
        map_source = dmr()->root()->find_map_source(map_name);
    else // get enclosing Group and lookup Map there
        map_source = top_group()->find_map_source(map_name);
 
    // Change: If the parser is in 'strict' mode (the default) and the Array named by
    // the Map cannot be fond, it is an error. If 'strict' mode is false (permissive
    // mode), then this is not an error. However, the Array referenced by the Map will
    // be null. This is a change in the parser's behavior to accommodate requests for
    // Arrays that include Maps that do not also include the Map(s) in the request.
    // See https://opendap.atlassian.net/browse/HYRAX-98. jhrg 4/13/16
    if (!map_source && d_strict)
        throw Error("The Map '" + map_name + "' was not found while parsing the variable '" + a->name() + "'.");
 
    a->maps()->add_map(new D4Map(map_name, map_source));
 
    return true;
}
 
bool D4ParserSax2::process_group(const char *name, const xmlChar **attrs, int nb_attributes) {
    if (is_not(name, "Group"))
        return false;
 
    transfer_xml_attrs(attrs, nb_attributes);
 
    if (!check_required_attribute("name")) {
        dmr_error(this, "The required attribute 'name' was missing from a Group element.");
        return false;
    }
 
    BaseType *btp = dmr()->factory()->NewVariable(dods_group_c, xml_attrs["name"].value);
    if (!btp) {
        dmr_fatal_error(this, "Could not instantiate the Group '%s'.", xml_attrs["name"].value.c_str());
        return false;
    }
 
    D4Group *grp = static_cast<D4Group *>(btp);
 
    // Need to set this to get the D4Attribute behavior in the type classes
    // shared between DAP2 and DAP4. jhrg 4/18/13
    grp->set_is_dap4(true);
 
    // link it up and change the current group
    D4Group *parent = top_group();
    if (!parent) {
        dmr_fatal_error(this, "No Group on the Group stack.");
        return false;
    }
 
    grp->set_parent(parent);
    parent->add_group_nocopy(grp);
 
    push_group(grp);
    push_attributes(grp->attributes());
    return true;
}

inline bool D4ParserSax2::process_attribute(const char *name, const xmlChar **attrs, int nb_attributes) {
    if (is_not(name, "Attribute"))
        return false;
 
    // These methods set the state to parser_error if a problem is found.
    transfer_xml_attrs(attrs, nb_attributes);
 
    // add error
    if (!(check_required_attribute(string("name")) && check_required_attribute(string("type")))) {
        dmr_error(this, "The required attribute 'name' or 'type' was missing from an Attribute element.");
        return false;
    }
 
    if (xml_attrs["type"].value == "Container") {
        push_state(inside_attribute_container);
 
        DBG(cerr << "Pushing attribute container " << xml_attrs["name"].value << endl);
        D4Attribute *child = new D4Attribute(xml_attrs["name"].value, attr_container_c);
 
        D4Attributes *tos = top_attributes();
        // add return
        if (!tos) {
            delete child;
            dmr_fatal_error(this, "Expected an Attribute container on the top of the attribute stack.");
            return false;
        }
 
        tos->add_attribute_nocopy(child);
        push_attributes(child->attributes());
    } else if (xml_attrs["type"].value == "OtherXML") {
        push_state(inside_other_xml_attribute);
 
        dods_attr_name = xml_attrs["name"].value;
        dods_attr_type = xml_attrs["type"].value;
    } else {
        push_state(inside_attribute);
 
        dods_attr_name = xml_attrs["name"].value;
        dods_attr_type = xml_attrs["type"].value;
    }
 
    return true;
}

inline bool D4ParserSax2::process_enum_def(const char *name, const xmlChar **attrs, int nb_attributes) {
    if (is_not(name, "Enumeration"))
        return false;
 
    transfer_xml_attrs(attrs, nb_attributes);
 
    if (!(check_required_attribute("name") && check_required_attribute("basetype"))) {
        dmr_error(this, "The required attribute 'name' or 'basetype' was missing from an Enumeration element.");
        return false;
    }
 
    Type t = get_type(xml_attrs["basetype"].value.c_str());
    if (!is_integer_type(t)) {
        dmr_error(this, "The Enumeration '%s' must have an integer type, instead the type '%s' was used.",
                  xml_attrs["name"].value.c_str(), xml_attrs["basetype"].value.c_str());
        return false;
    }
 
    // This getter allocates a new object if needed.
    string enum_def_path = xml_attrs["name"].value;
#if 0
    // Use FQNs when things are referenced, not when they are defined
    if (xml_attrs["name"].value[0] != '/')
        enum_def_path = top_group()->FQN() + enum_def_path;
#endif
    enum_def()->set_name(enum_def_path);
    enum_def()->set_type(t);
 
    return true;
}
 
inline bool D4ParserSax2::process_enum_const(const char *name, const xmlChar **attrs, int nb_attributes) {
    if (is_not(name, "EnumConst"))
        return false;
 
    // These methods set the state to parser_error if a problem is found.
    transfer_xml_attrs(attrs, nb_attributes);
 
    if (!(check_required_attribute("name") && check_required_attribute("value"))) {
        dmr_error(this, "The required attribute 'name' or 'value' was missing from an EnumConst element.");
        return false;
    }
 
    istringstream iss(xml_attrs["value"].value);
    long long value = 0;
    iss >> skipws >> value;
    if (iss.fail() || iss.bad()) {
        dmr_error(this, "Expected an integer value for an Enumeration constant, got '%s' instead.",
                  xml_attrs["value"].value.c_str());
    } else if (!enum_def()->is_valid_enum_value(value)) {
        dmr_error(this, "In an Enumeration constant, the value '%s' cannot fit in a variable of type '%s'.",
                  xml_attrs["value"].value.c_str(), D4type_name(d_enum_def->type()).c_str());
    } else {
        // unfortunate choice of names... args are 'label' and 'value'
        enum_def()->add_value(xml_attrs["name"].value, value);
    }
 
    return true;
}

inline bool D4ParserSax2::process_variable(const char *name, const xmlChar **attrs, int nb_attributes) {
    Type t = get_type(name);
    if (is_simple_type(t)) {
        process_variable_helper(t, inside_simple_type, attrs, nb_attributes);
        return true;
    } else {
        switch (t) {
        case dods_structure_c:
            process_variable_helper(t, inside_constructor, attrs, nb_attributes);
            return true;
 
        case dods_sequence_c:
            process_variable_helper(t, inside_constructor, attrs, nb_attributes);
            return true;
 
        default:
            return false;
        }
    }
}

void D4ParserSax2::process_variable_helper(Type t, ParseState s, const xmlChar **attrs, int nb_attributes) {
    transfer_xml_attrs(attrs, nb_attributes);
 
    if (check_required_attribute("name")) {
        BaseType *btp = dmr()->factory()->NewVariable(t, xml_attrs["name"].value);
        if (!btp) {
            dmr_fatal_error(this, "Could not instantiate the variable '%s'.", xml_attrs["name"].value.c_str());
            return;
        }
 
        if ((t == dods_enum_c) && check_required_attribute("enum")) {
            D4EnumDef *enum_def = 0;
            string enum_path = xml_attrs["enum"].value;
            if (enum_path[0] == '/')
                enum_def = dmr()->root()->find_enum_def(enum_path);
            else
                enum_def = top_group()->find_enum_def(enum_path);
 
            if (!enum_def)
                dmr_fatal_error(this, "Could not find the Enumeration definition '%s'.", enum_path.c_str());
 
            static_cast<D4Enum *>(btp)->set_enumeration(enum_def);
        }
 
        btp->set_is_dap4(true); // see comment above
        push_basetype(btp);
 
        push_attributes(btp->attributes());
 
        push_state(s);
    }
}


void D4ParserSax2::dmr_start_document(void *p) {
    D4ParserSax2 *parser = static_cast<D4ParserSax2 *>(p);
    parser->d_error_msg = "";
    parser->char_data = "";
 
    // Set this in intern_helper so that the loop test for the parser_end
    // state works for the first iteration. It seems like XMLParseChunk calls this
    // function on it's first run. jhrg 9/16/13
    // parser->push_state(parser_start);
 
    parser->push_attributes(parser->dmr()->root()->attributes());
 
    if (parser->debug())
        cerr << "Parser start state: " << states[parser->get_state()] << endl;
}

void D4ParserSax2::dmr_end_document(void *p) {
    D4ParserSax2 *parser = static_cast<D4ParserSax2 *>(p);
 
    if (parser->debug())
        cerr << "Parser end state: " << states[parser->get_state()] << endl;
 
    if (parser->get_state() != parser_end)
        D4ParserSax2::dmr_error(parser, "The document contained unbalanced tags.");
 
    // If we've found any sort of error, don't make the DMR; intern() will
    // take care of the error.
    if (parser->get_state() == parser_error || parser->get_state() == parser_fatal_error)
        return;
 
    if (!parser->empty_basetype() || parser->empty_group())
        D4ParserSax2::dmr_error(parser,
                                "The document did not contain a valid root Group or contained unbalanced tags.");
 
    parser->pop_group(); // leave the stack 'clean'
    parser->pop_attributes();
}

void D4ParserSax2::dmr_start_element(void *p, const xmlChar *l, const xmlChar *prefix, const xmlChar *URI,
                                     int nb_namespaces, const xmlChar **namespaces, int nb_attributes,
                                     int /*nb_defaulted*/, const xmlChar **attributes) {
    D4ParserSax2 *parser = static_cast<D4ParserSax2 *>(p);
    const char *localname = (const char *)l;
 
    if (parser->debug())
        cerr << "Start element " << localname << "  prefix:  " << (prefix ? (char *)prefix : "null")
             << "  ns: " << (URI ? (char *)URI : "null") << " (state: " << states[parser->get_state()] << ")" << endl;
 
    if (parser->get_state() != parser_error) {
        string dap4_ns_name = DapXmlNamspaces::getDapNamespaceString(DAP_4_0);
        if (parser->debug())
            cerr << "dap4_ns_name:         " << dap4_ns_name << endl;
 
        string this_element_ns_name = (URI != 0) ? ((char *)URI) : "";
        if (parser->debug())
            cerr << "this_element_ns_name: " << this_element_ns_name << endl;
 
        if (this_element_ns_name.compare(dap4_ns_name)) {
            if (parser->debug())
                cerr << "Start of non DAP4 element: " << localname << " detected." << endl;
            parser->push_state(not_dap4_element);
            // return;
        }
    }
 
    switch (parser->get_state()) {
    case parser_start:
        if (is_not(localname, "Dataset"))
            D4ParserSax2::dmr_error(parser, "Expected DMR to start with a Dataset element; found '%s' instead.",
                                    localname);
 
        parser->root_ns = URI ? (const char *)URI : "";
        parser->transfer_xml_attrs(attributes, nb_attributes);
 
        if (parser->check_required_attribute(string("name")))
            parser->dmr()->set_name(parser->xml_attrs["name"].value);
 
        if (parser->check_attribute("dapVersion"))
            parser->dmr()->set_dap_version(parser->xml_attrs["dapVersion"].value);
 
        if (parser->check_attribute("dmrVersion"))
            parser->dmr()->set_dmr_version(parser->xml_attrs["dmrVersion"].value);
 
        if (parser->check_attribute("base"))
            parser->dmr()->set_request_xml_base(parser->xml_attrs["base"].value);
 
        if (!parser->root_ns.empty())
            parser->dmr()->set_namespace(parser->root_ns);
 
        // Push the root Group on the stack
        parser->push_group(parser->dmr()->root());
 
        parser->push_state(inside_dataset);
 
        break;
 
        // Both inside dataset and inside group can have the same stuff.
        // The difference is that the Dataset holds the root group, which
        // must be present; other groups are optional
    case inside_dataset:
    case inside_group:
        if (parser->process_enum_def(localname, attributes, nb_attributes))
            parser->push_state(inside_enum_def);
        else if (parser->process_dimension_def(localname, attributes, nb_attributes))
            parser->push_state(inside_dim_def);
        else if (parser->process_group(localname, attributes, nb_attributes))
            parser->push_state(inside_group);
        else if (parser->process_variable(localname, attributes, nb_attributes))
            // This will push either inside_simple_type or inside_structure
            // onto the parser state stack.
            break;
        else if (parser->process_attribute(localname, attributes, nb_attributes))
            // This will push either inside_attribute, inside_attribute_container
            // or inside_otherxml_attribute onto the parser state stack
            break;
        else
            D4ParserSax2::dmr_error(
                parser, "Expected an Attribute, Enumeration, Dimension, Group or variable element; found '%s' instead.",
                localname);
        break;
 
    case inside_attribute_container:
        if (parser->process_attribute(localname, attributes, nb_attributes))
            break;
        else
            D4ParserSax2::dmr_error(parser, "Expected an Attribute element; found '%s' instead.", localname);
        break;
 
    case inside_attribute:
        if (parser->process_attribute(localname, attributes, nb_attributes))
            break;
        else if (strcmp(localname, "Value") == 0)
            parser->push_state(inside_attribute_value);
        else
            dmr_error(parser, "Expected an 'Attribute' or 'Value' element; found '%s' instead.", localname);
        break;
 
    case inside_attribute_value:
        // Attribute values are processed by the end element code.
        break;
 
    case inside_other_xml_attribute:
        parser->other_xml_depth++;
 
        // Accumulate the elements here
        parser->other_xml.append("<");
        if (prefix) {
            parser->other_xml.append((const char *)prefix);
            parser->other_xml.append(":");
        }
        parser->other_xml.append(localname);
 
        if (nb_namespaces != 0) {
            parser->transfer_xml_ns(namespaces, nb_namespaces);
 
            for (map<string, string>::iterator i = parser->namespace_table.begin(); i != parser->namespace_table.end();
                 ++i) {
                parser->other_xml.append(" xmlns");
                if (!i->first.empty()) {
                    parser->other_xml.append(":");
                    parser->other_xml.append(i->first);
                }
                parser->other_xml.append("=\"");
                parser->other_xml.append(i->second);
                parser->other_xml.append("\"");
            }
        }
 
        if (nb_attributes != 0) {
            parser->transfer_xml_attrs(attributes, nb_attributes);
            for (XMLAttrMap::iterator i = parser->xml_attr_begin(); i != parser->xml_attr_end(); ++i) {
                parser->other_xml.append(" ");
                if (!i->second.prefix.empty()) {
                    parser->other_xml.append(i->second.prefix);
                    parser->other_xml.append(":");
                }
                parser->other_xml.append(i->first);
                parser->other_xml.append("=\"");
                parser->other_xml.append(i->second.value);
                parser->other_xml.append("\"");
            }
        }
 
        parser->other_xml.append(">");
        break;
 
    case inside_enum_def:
        // process an EnumConst element
        if (parser->process_enum_const(localname, attributes, nb_attributes))
            parser->push_state(inside_enum_const);
        else
            dmr_error(parser, "Expected an 'EnumConst' element; found '%s' instead.", localname);
        break;
 
    case inside_enum_const:
        // No content; nothing to do
        break;
 
    case inside_dim_def:
        // No content; nothing to do
        break;
#if 0
        case inside_dimension:
            // No content.
            break;
#endif
    case inside_dim:
        // No content.
        break;
 
    case inside_map:
        // No content.
        break;
 
    case inside_simple_type:
        if (parser->process_attribute(localname, attributes, nb_attributes))
            break;
        else if (parser->process_dimension(localname, attributes, nb_attributes))
            parser->push_state(inside_dim);
        else if (parser->process_map(localname, attributes, nb_attributes))
            parser->push_state(inside_map);
        else
            dmr_error(parser, "Expected an 'Attribute', 'Dim' or 'Map' element; found '%s' instead.", localname);
        break;
 
    case inside_constructor:
        if (parser->process_variable(localname, attributes, nb_attributes))
            // This will push either inside_simple_type or inside_structure
            // onto the parser state stack.
            break;
        else if (parser->process_attribute(localname, attributes, nb_attributes))
            break;
        else if (parser->process_dimension(localname, attributes, nb_attributes))
            parser->push_state(inside_dim);
        else if (parser->process_map(localname, attributes, nb_attributes))
            parser->push_state(inside_map);
        else
            D4ParserSax2::dmr_error(parser, "Expected an Attribute, Dim, Map or variable element; found '%s' instead.",
                                    localname);
        break;
 
    case not_dap4_element:
        if (parser->debug())
            cerr << "Inside non DAP4 element. localname: " << localname << endl;
        break;
 
    case parser_unknown:
        // FIXME?
        // *** Never used? If so remove/error
        parser->push_state(parser_unknown);
        break;
 
    case parser_error:
    case parser_fatal_error:
        break;
 
    case parser_end:
        // FIXME Error?
        break;
    }
 
    if (parser->debug())
        cerr << "Start element exit state: " << states[parser->get_state()] << endl;
}
 
void D4ParserSax2::dmr_end_element(void *p, const xmlChar *l, const xmlChar *prefix, const xmlChar *URI) {
    D4ParserSax2 *parser = static_cast<D4ParserSax2 *>(p);
    const char *localname = (const char *)l;
 
    if (parser->debug())
        cerr << "End element " << localname << " (state " << states[parser->get_state()] << ")" << endl;
 
    switch (parser->get_state()) {
    case parser_start:
        dmr_fatal_error(parser, "Unexpected state, inside start state while processing element '%s'.", localname);
        break;
 
    case inside_dataset:
        if (is_not(localname, "Dataset"))
            D4ParserSax2::dmr_error(parser, "Expected an end Dataset tag; found '%s' instead.", localname);
 
        parser->pop_state();
        if (parser->get_state() != parser_start)
            dmr_fatal_error(parser, "Unexpected state, expected start state.");
        else {
            parser->pop_state();
            parser->push_state(parser_end);
        }
        break;
 
    case inside_group: {
        if (is_not(localname, "Group"))
            D4ParserSax2::dmr_error(parser, "Expected an end tag for a Group; found '%s' instead.", localname);
 
        if (!parser->empty_basetype() || parser->empty_group())
            D4ParserSax2::dmr_error(parser,
                                    "The document did not contain a valid root Group or contained unbalanced tags.");
 
        parser->pop_group();
        parser->pop_state();
        break;
    }
 
    case inside_attribute_container:
        if (is_not(localname, "Attribute"))
            D4ParserSax2::dmr_error(parser, "Expected an end Attribute tag; found '%s' instead.", localname);
 
        parser->pop_state();
        parser->pop_attributes();
        break;
 
    case inside_attribute:
        if (is_not(localname, "Attribute"))
            D4ParserSax2::dmr_error(parser, "Expected an end Attribute tag; found '%s' instead.", localname);
 
        parser->pop_state();
        break;
 
    case inside_attribute_value: {
        if (is_not(localname, "Value"))
            D4ParserSax2::dmr_error(parser, "Expected an end value tag; found '%s' instead.", localname);
 
        parser->pop_state();
 
        // The old code added more values using the name and type as
        // indexes to find the correct attribute. Use get() for that
        // now. Or fix this code to keep a pointer to the to attribute...
        D4Attributes *attrs = parser->top_attributes();
        D4Attribute *attr = attrs->get(parser->dods_attr_name);
        if (!attr) {
            attr = new D4Attribute(parser->dods_attr_name, StringToD4AttributeType(parser->dods_attr_type));
            attrs->add_attribute_nocopy(attr);
        }
        attr->add_value(parser->char_data);
 
        parser->char_data = ""; // Null this after use.
        break;
    }
 
    case inside_other_xml_attribute: {
        if (strcmp(localname, "Attribute") == 0 && parser->root_ns == (const char *)URI) {
            parser->pop_state();
 
            // The old code added more values using the name and type as
            // indexes to find the correct attribute. Use get() for that
            // now. Or fix this code to keep a pointer to the to attribute...
            D4Attributes *attrs = parser->top_attributes();
            D4Attribute *attr = attrs->get(parser->dods_attr_name);
            if (!attr) {
                attr = new D4Attribute(parser->dods_attr_name, StringToD4AttributeType(parser->dods_attr_type));
                attrs->add_attribute_nocopy(attr);
            }
            attr->add_value(parser->other_xml);
 
            parser->other_xml = ""; // Null this after use.
        } else {
            if (parser->other_xml_depth == 0) {
                D4ParserSax2::dmr_error(parser, "Expected an OtherXML attribute to end! Instead I found '%s'",
                                        localname);
                break;
            }
            parser->other_xml_depth--;
 
            parser->other_xml.append("</");
            if (prefix) {
                parser->other_xml.append((const char *)prefix);
                parser->other_xml.append(":");
            }
            parser->other_xml.append(localname);
            parser->other_xml.append(">");
        }
        break;
    }
 
    case inside_enum_def:
        if (is_not(localname, "Enumeration"))
            D4ParserSax2::dmr_error(parser, "Expected an end Enumeration tag; found '%s' instead.", localname);
        if (!parser->top_group())
            D4ParserSax2::dmr_fatal_error(
                parser, "Expected a Group to be the current item, while finishing up an Enumeration.");
        else {
            // copy the pointer; not a deep copy
            parser->top_group()->enum_defs()->add_enum_nocopy(parser->enum_def());
            // Set the enum_def to null; next call to enum_def() will
            // allocate a new object
            parser->clear_enum_def();
            parser->pop_state();
        }
        break;
 
    case inside_enum_const:
        if (is_not(localname, "EnumConst"))
            D4ParserSax2::dmr_error(parser, "Expected an end EnumConst tag; found '%s' instead.", localname);
 
        parser->pop_state();
        break;
 
    case inside_dim_def: {
        if (is_not(localname, "Dimension"))
            D4ParserSax2::dmr_error(parser, "Expected an end Dimension tag; found '%s' instead.", localname);
 
        if (!parser->top_group())
            D4ParserSax2::dmr_error(parser,
                                    "Expected a Group to be the current item, while finishing up an Dimension.");
 
        // FIXME Use the Group on the top of the group stack
        // copy the pointer; not a deep copy
        parser->top_group()->dims()->add_dim_nocopy(parser->dim_def());
        // parser->dmr()->root()->dims()->add_dim_nocopy(parser->dim_def());
        //  Set the dim_def to null; next call to dim_def() will
        //  allocate a new object. Calling 'clear' is important because
        //  the cleanup method will free dim_def if it's not null and
        //  we just copied the pointer in the add_dim_nocopy() call
        //  above.
        parser->clear_dim_def();
        parser->pop_state();
        break;
    }
 
    case inside_simple_type:
        if (is_simple_type(get_type(localname))) {
            BaseType *btp = parser->top_basetype();
            parser->pop_basetype();
            parser->pop_attributes();
 
            BaseType *parent = 0;
            if (!parser->empty_basetype())
                parent = parser->top_basetype();
            else if (!parser->empty_group())
                parent = parser->top_group();
            else {
                dmr_fatal_error(parser, "Both the Variable and Groups stacks are empty while closing a %s element.",
                                localname);
                delete btp;
                parser->pop_state();
                break;
            }
 
            if (parent->type() == dods_array_c)
                static_cast<Array *>(parent)->prototype()->add_var_nocopy(btp);
            else
                parent->add_var_nocopy(btp);
        } else
            D4ParserSax2::dmr_error(parser, "Expected an end tag for a simple type; found '%s' instead.", localname);
 
        parser->pop_state();
        break;
 
    case inside_dim:
        if (is_not(localname, "Dim"))
            D4ParserSax2::dmr_fatal_error(parser, "Expected an end Dim tag; found '%s' instead.", localname);
 
        parser->pop_state();
        break;
 
    case inside_map:
        if (is_not(localname, "Map"))
            D4ParserSax2::dmr_fatal_error(parser, "Expected an end Map tag; found '%s' instead.", localname);
 
        parser->pop_state();
        break;
 
    case inside_constructor: {
        if (strcmp(localname, "Structure") != 0 && strcmp(localname, "Sequence") != 0) {
            D4ParserSax2::dmr_error(parser, "Expected an end tag for a constructor; found '%s' instead.", localname);
            return;
        }
 
        BaseType *btp = parser->top_basetype();
        parser->pop_basetype();
        parser->pop_attributes();
 
        BaseType *parent = 0;
        if (!parser->empty_basetype())
            parent = parser->top_basetype();
        else if (!parser->empty_group())
            parent = parser->top_group();
        else {
            dmr_fatal_error(parser, "Both the Variable and Groups stacks are empty while closing a %s element.",
                            localname);
            delete btp;
            parser->pop_state();
            break;
        }
 
        // TODO Why doesn't this code mirror the simple_var case and test
        // for the parent being an array? jhrg 10/13/13
        parent->add_var_nocopy(btp);
        parser->pop_state();
        break;
    }
 
    case not_dap4_element:
        if (parser->debug())
            cerr << "End of non DAP4 element: " << localname << endl;
        parser->pop_state();
        break;
 
    case parser_unknown:
        parser->pop_state();
        break;
 
    case parser_error:
    case parser_fatal_error:
        break;
 
    case parser_end:
        // FIXME Error?
        break;
    }
 
    if (parser->debug())
        cerr << "End element exit state: " << states[parser->get_state()] << endl;
}

void D4ParserSax2::dmr_get_characters(void *p, const xmlChar *ch, int len) {
    D4ParserSax2 *parser = static_cast<D4ParserSax2 *>(p);
 
    switch (parser->get_state()) {
    case inside_attribute_value:
        parser->char_data.append((const char *)(ch), len);
        DBG(cerr << "Characters: '" << parser->char_data << "'" << endl);
        break;
 
    case inside_other_xml_attribute:
        parser->other_xml.append((const char *)(ch), len);
        DBG(cerr << "Other XML Characters: '" << parser->other_xml << "'" << endl);
        break;
 
    default:
        break;
    }
}

void D4ParserSax2::dmr_ignoreable_whitespace(void *p, const xmlChar *ch, int len) {
    D4ParserSax2 *parser = static_cast<D4ParserSax2 *>(p);
 
    switch (parser->get_state()) {
    case inside_other_xml_attribute:
        parser->other_xml.append((const char *)(ch), len);
        break;
 
    default:
        break;
    }
}

void D4ParserSax2::dmr_get_cdata(void *p, const xmlChar *value, int len) {
    D4ParserSax2 *parser = static_cast<D4ParserSax2 *>(p);
 
    switch (parser->get_state()) {
    case inside_other_xml_attribute:
        parser->other_xml.append((const char *)(value), len);
        break;
 
    case parser_unknown:
        break;
 
    default:
        D4ParserSax2::dmr_error(parser, "Found a CData block but none are allowed by DAP4.");
 
        break;
    }
}

xmlEntityPtr D4ParserSax2::dmr_get_entity(void *, const xmlChar *name) { return xmlGetPredefinedEntity(name); }

void D4ParserSax2::dmr_fatal_error(void *p, const char *msg, ...) {
    va_list args;
    D4ParserSax2 *parser = static_cast<D4ParserSax2 *>(p);
 
    parser->push_state(parser_fatal_error);
 
    va_start(args, msg);
    char str[1024];
    vsnprintf(str, 1024, msg, args);
    va_end(args);
 
    int line = xmlSAX2GetLineNumber(parser->d_context);
 
    if (!parser->d_error_msg.empty())
        parser->d_error_msg += "\n";
    parser->d_error_msg += "At line " + long_to_string(line) + ": " + string(str);
}
 
void D4ParserSax2::dmr_error(void *p, const char *msg, ...) {
    va_list args;
    D4ParserSax2 *parser = static_cast<D4ParserSax2 *>(p);
 
    parser->push_state(parser_error);
 
    va_start(args, msg);
    char str[1024];
    vsnprintf(str, 1024, msg, args);
    va_end(args);
 
    int line = xmlSAX2GetLineNumber(parser->d_context);
 
    if (!parser->d_error_msg.empty())
        parser->d_error_msg += "\n";
    parser->d_error_msg += "At line " + long_to_string(line) + ": " + string(str);
}


void D4ParserSax2::cleanup_parse() {
    bool wellFormed = d_context->wellFormed;
    bool valid = d_context->valid;
 
    // d_context->sax = NULL;
    xmlFreeParserCtxt(d_context);
 
    delete d_enum_def;
    d_enum_def = 0;
 
    delete d_dim_def;
    d_dim_def = 0;
 
    // If there's an error, there may still be items on the stack at the
    // end of the parse.
    while (!btp_stack.empty()) {
        delete top_basetype();
        pop_basetype();
    }
 
    if (!wellFormed)
        throw Error("The DMR was not well formed. " + d_error_msg);
    else if (!valid)
        throw Error("The DMR was not valid." + d_error_msg);
    else if (get_state() == parser_error)
        throw Error(d_error_msg);
    else if (get_state() == parser_fatal_error)
        throw InternalErr(d_error_msg);
}

void D4ParserSax2::intern(istream &f, DMR *dest_dmr, bool debug) {
    d_debug = debug;
 
    // Code example from libxml2 docs re: read from a stream.
 
    if (!f.good())
        throw Error("Input stream not open or read error");
    if (!dest_dmr)
        throw InternalErr(__FILE__, __LINE__, "DMR object is null");
 
    d_dmr = dest_dmr; // dump values here
#if 0
    int line_num = 1;
    string line;
 
    // Get the <xml ... ?> line
    getline(f, line);
    if (line.length() == 0) throw Error("No input found while parsing the DMR.");
 
    if (debug) cerr << "line: (" << line_num << "): " << endl << line << endl << endl;
 
    d_context = xmlCreatePushParserCtxt(&d_dmr_sax_parser, this, line.c_str(), line.length(), "stream");
    d_context->validate = true;
    push_state(parser_start);
 
    // Get the first line of stuff
    getline(f, line);
    ++line_num;
 
    if (debug) cerr << "line: (" << line_num << "): " << endl << line << endl << endl;
 
    while (!f.eof() && (get_state() != parser_end)) {
        xmlParseChunk(d_context, line.c_str(), line.length(), 0);
 
        // Get the next line
        getline(f, line);
        ++line_num;
 
        if (debug) cerr << "line: (" << line_num << "): " << endl << line << endl << endl;
    }
    // This call ends the parse.
    xmlParseChunk(d_context, line.c_str(), 0, 1/*terminate*/);
 
#else
    int line_num = 1;
    string line;
 
    // Get the XML prolog line (looks like: <?xml ... ?> )
    getline(f, line);
    if (line.length() == 0)
        throw Error("No input found while parsing the DMR.");
 
    if (debug)
        cerr << "line: (" << line_num << "): " << endl << line << endl << endl;
 
    d_context = xmlCreatePushParserCtxt(&d_dmr_sax_parser, this, line.c_str(), line.length(), "stream");
    d_context->validate = true;
    push_state(parser_start);
 
    // Get the first chunk of the stuff
    long chunk_count = 0;
    long chunk_size = 0;
 
    f.read(d_parse_buffer, D4_PARSE_BUFF_SIZE);
    chunk_size = f.gcount();
    d_parse_buffer[chunk_size] =
        0; // null terminate the string. We can do it this way because the buffer is +1 bigger than D4_PARSE_BUFF_SIZE
    if (debug)
        cerr << "chunk: (" << chunk_count++ << "): " << endl << d_parse_buffer << endl << endl;
 
    while (!f.eof() && (get_state() != parser_end)) {
 
        xmlParseChunk(d_context, d_parse_buffer, chunk_size, 0);
 
        // There is more to read. Get the next chunk
        f.read(d_parse_buffer, D4_PARSE_BUFF_SIZE);
        chunk_size = f.gcount();
        d_parse_buffer[chunk_size] = 0; // null terminate the string. We can do it this way because the buffer is +1
                                        // bigger than D4_PARSE_BUFF_SIZE
        if (debug)
            cerr << "chunk: (" << chunk_count++ << "): " << endl << d_parse_buffer << endl << endl;
    }
 
    // This call ends the parse.
    xmlParseChunk(d_context, d_parse_buffer, chunk_size, 1 /*terminate*/);
#endif
 
    // This checks that the state on the parser stack is parser_end and throws
    // an exception if it's not (i.e., the loop exited with gcount() == 0).
    cleanup_parse();
}

void D4ParserSax2::intern(const string &document, DMR *dest_dmr, bool debug) {
    intern(document.c_str(), document.length(), dest_dmr, debug);
}

void D4ParserSax2::intern(const char *buffer, int size, DMR *dest_dmr, bool debug) {
    if (!(size > 0))
        return;
 
    d_debug = debug;
 
    // Code example from libxml2 docs re: read from a stream.
 
    if (!dest_dmr)
        throw InternalErr(__FILE__, __LINE__, "DMR object is null");
    d_dmr = dest_dmr; // dump values in dest_dmr
 
    push_state(parser_start);
    d_context = xmlCreatePushParserCtxt(&d_dmr_sax_parser, this, buffer, size, "stream");
    d_context->validate = true;
 
    // This call ends the parse.
    xmlParseChunk(d_context, buffer, 0, 1 /*terminate*/);
 
    // This checks that the state on the parser stack is parser_end and throws
    // an exception if it's not (i.e., the loop exited with gcount() == 0).
    cleanup_parse();
}
 
} // namespace libdap