inkscape/src/uri-references.cpp

	uri-references.cpp revision 901d2d4a59790c220c6589e17dbbf556d47dfe71
/**
 * 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 <iostream>
#include <cstring>
#include <string>

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

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

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(NULL), _owner_document(owner_document), _obj(NULL), _uri(NULL)
{
    g_assert(_owner_document != NULL);
}

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

/*
 * The main ideas here are:
 * (1) "If we are inside a clone, then we can accept if and only if our "original thing" can accept the reference"
 * (this caused problems when there are clones because a change in ids triggers signals for the object hrefing this id, but also its cloned reprs
 * (descendants of <use> referencing an ancestor of the href'ing object)). The way it is done here is *atrocious*, but i could not find a better way.
 * FIXME: find a better and safer way to find the "original object" of anyone with the flag ->cloned
 *
 * (2) Once we have an (potential owner) object, it can accept a href to obj, iff the graph of objects where directed edges are
 * either parent->child relations , *** or href'ing to href'ed *** relations, stays acyclic.
 * We can go either from owner and up in the tree, or from obj and down, in either case this will be in the worst case linear in the number of objects.
 * There are no easy objects allowing to do the second proposition, while "hrefList" is a "list of objects href'ing us", so we'll take this.
 * Then we keep a set of already visited elements, and do a DFS on this graph. if we find obj, then BOOM.
 */

bool URIReference::_acceptObject(SPObject *obj) const {
    //we go back following hrefList and parent to find if the object already references ourselves indirectly
    std::set<SPObject*> done;
    SPObject * owner = getOwner();
    if(!owner)return true;
    while(owner->cloned){
        std::vector<int> positions;
        while(owner->cloned){
            int position=0;
            SPObject* c = owner->parent->firstChild();
            while(c != owner && dynamic_cast<SPObject*>(c) ){position++;c=c->next;}
            positions.push_back(position);
            owner=owner->parent;
        }
            owner = ((SPUse*)owner)->get_original();
            for(int i=positions.size()-2;i>=0;i--)owner=owner->childList(false)[positions[i]];
    }
    //once we have the "original" object (hopefully) we look at who is referencing it
    std::list<SPObject*> todo(owner->hrefList);
    todo.push_front(owner->parent);
    while(!todo.empty()){
        SPObject* e = todo.front();
        todo.pop_front();
        if(!dynamic_cast<SPObject*>(e))continue;
        if(done.insert(e).second){
            if(e==obj){return false;}
            todo.push_front(e->parent);
            todo.insert(todo.begin(),e->hrefList.begin(),e->hrefList.end());
        }
    }
    return true;
}


void URIReference::attach(const URI &uri) throw(BadURIException)
{
    SPDocument *document = NULL;

    // Attempt to get the document that contains the URI
    if (_owner) {
        document = _owner->document;
    } else if (_owner_document) {
        document = _owner_document;
    }

    // createChildDoc() assumes that the referenced file is an SVG.
    // PNG and JPG files are allowed (in the case of feImage).
    gchar *filename = uri.toString();
    bool skip = false;
    if( g_str_has_suffix( filename, ".jpg" ) ||
        g_str_has_suffix( filename, ".JPG" ) ||
        g_str_has_suffix( filename, ".png" ) ||
        g_str_has_suffix( filename, ".PNG" ) ) {
        skip = true;
    }

    // The path contains references to separate document files to load.
    if(document && uri.getPath() && !skip ) {
        std::string base = document->getBase() ? document->getBase() : "";
        std::string path = uri.getFullPath(base);
        if(!path.empty()) {
            document = document->createChildDoc(path);
        } else {
            document = NULL;
        }
    }
    if(!document) {
        g_warning("Can't get document for referenced URI: %s", filename);
        g_free( filename );
        return;
    }
    g_free( filename );

    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 = NULL;
    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 */

    _connection.disconnect();
    delete _uri;
    _uri = new URI(uri);

    _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 */


SPObject* sp_css_uri_reference_resolve( SPDocument *document, const gchar *uri )
{
    SPObject* ref = NULL;

    if ( document && uri && ( strncmp(uri, "url(", 4) == 0 ) ) {
        gchar *trimmed = extract_uri( uri );
        if ( trimmed ) {
            ref = sp_uri_reference_resolve( document, trimmed );
            g_free( trimmed );
        }
    }

    return ref;
}

SPObject *
sp_uri_reference_resolve (SPDocument *document, const gchar *uri)
{
    SPObject* ref = NULL;

    if ( uri && (*uri == '#') ) {
        ref = document->getObjectById( uri + 1 );
    }

    return ref;
}

/*
  Local Variables:
  mode:c++
  c-file-style:"stroustrup"
  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
  indent-tabs-mode:nil
  fill-column:99
  End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8 :