inkscape/src/uri-references.cpp

	uri-references.cpp revision 3a8e479f331858946168c32bfc7622c9010b6680
#define __SP_URI_REFERENCES_C__

/*
 * Helper methods for resolving URI References
 *
 * Authors:
 *   Lauris Kaplinski <lauris@kaplinski.com>
 *
 * Copyright (C) 2001-2002 Lauris Kaplinski
 * Copyright (C) 2001 Ximian, Inc.
 *
 * Released under GNU GPL, read the file 'COPYING' for more information
 */

#include "document.h"
#include "sp-object.h"
#include "uri.h"
#include "uri-references.h"

#include <sigc++/functors/mem_fun.h>

static gchar *uri_to_id(SPDocument *document, const gchar *uri);

namespace Inkscape {

URIReference::URIReference(SPObject *owner)
    : _owner(owner), _owner_document(NULL), _obj(NULL), _uri(NULL)
{
    g_assert(_owner != NULL);
    /* FIXME !!! attach to owner's destroy signal to clean up in case */
}

URIReference::URIReference(SPDocument *owner_document)
    : _owner_document(owner_document), _owner(NULL), _obj(NULL), _uri(NULL)
{
    g_assert(_owner_document != NULL);
}

URIReference::~URIReference() {
    detach();
}

void URIReference::attach(const URI &uri) throw(BadURIException)
{
    SPDocument *document;
  if (_owner) {
    document = SP_OBJECT_DOCUMENT(_owner);
    } else if (_owner_document) {
    document = _owner_document;
    } else {
    g_assert_not_reached();
    }
    gchar const *fragment = uri.getFragment();
    if ( !uri.isRelative() || uri.getQuery() || !fragment ) {
        throw UnsupportedURIException();
    }

    /* FIXME !!! real xpointer support should be delegated to document */
    /* for now this handles the minimal xpointer form that SVG 1.0
     * requires of us
     */
    gchar *id;
    if (!strncmp(fragment, "xpointer(", 9)) {
        /* FIXME !!! this is wasteful */
        /* FIXME: It looks as though this is including "))" in the id.  I suggest moving
           the strlen calculation and validity testing to before strdup, and copying just
           the id without the "))".  -- pjrm */
        if (!strncmp(fragment, "xpointer(id(", 12)) {
            id = g_strdup(fragment+12);
            size_t const len = strlen(id);
            if ( len < 3 || strcmp(id+len-2, "))") ) {
                g_free(id);
                throw MalformedURIException();
            }
        } else {
            throw UnsupportedURIException();
        }
    } else {
        id = g_strdup(fragment);
    }

    /* FIXME !!! validate id as an NCName somewhere */

    if (_uri) {
        delete _uri;
    }
    _uri = new URI(uri);

    _connection.disconnect();
    _setObject(document->getObjectById(id));
    _connection = document->connectIdChanged(id, sigc::mem_fun(*this, &URIReference::_setObject));

    g_free(id);
}

void URIReference::detach() {
    _connection.disconnect();
    delete _uri;
    _uri = NULL;
    _setObject(NULL);
}

void URIReference::_setObject(SPObject *obj) {
    if ( obj && !_acceptObject(obj) ) {
        obj = NULL;
    }

    if ( obj == _obj ) return;

    SPObject *old_obj=_obj;
    _obj = obj;

    _release_connection.disconnect();
    if (_obj) {
        sp_object_href(_obj, _owner);
        _release_connection = _obj->connectRelease(sigc::mem_fun(*this, &URIReference::_release));
    }
    _changed_signal.emit(old_obj, _obj);
    if (old_obj) {
        /* release the old object _after_ the signal emission */
        sp_object_hunref(old_obj, _owner);
    }
}

/* If an object is deleted, current semantics require that we release
 * it on its "release" signal, rather than later, when its ID is actually
 * unregistered from the document.
 */
void URIReference::_release(SPObject *obj) {
    g_assert( _obj == obj );
    _setObject(NULL);
}

} /* namespace Inkscape */

static gchar *
uri_to_id(SPDocument *document, const gchar *uri)
{
    const gchar *e;
    gchar *id;
    gint len;

    g_return_val_if_fail (document != NULL, NULL);

    if (!uri) return NULL;
    /* fixme: xpointer, everything */
    if (strncmp (uri, "url(#", 5)) return NULL;

    e = uri + 5;
    while (*e) {
        if (*e == ')') break;
        if (!isalnum (*e) && (*e != '_') && (*e != '-') && (*e != ':') && (*e != '.')) return NULL;
        e += 1;
        if (!*e) return NULL;
    }

    len = e - uri - 5;
    if (len < 1) return NULL;

    id = (gchar*)g_new(gchar, len + 1);
    memcpy (id, uri + 5, len);
    id[len] = '\0';

    return id;
}

SPObject *
sp_uri_reference_resolve (SPDocument *document, const gchar *uri)
{
    gchar *id;

    id = uri_to_id(document, uri);
    if (!id) return NULL;

    SPObject *ref;
    ref = document->getObjectById(id);
    g_free(id);
    return ref;
}