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-rw-r--r--src/object/uri-references.cpp290
1 files changed, 290 insertions, 0 deletions
diff --git a/src/object/uri-references.cpp b/src/object/uri-references.cpp
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+// SPDX-License-Identifier: GPL-2.0-or-later
+/**
+ * Helper methods for resolving URI References
+ *
+ * Authors:
+ * Lauris Kaplinski <lauris@kaplinski.com>
+ * Marc Jeanmougin
+ *
+ * Copyright (C) 2001-2002 Lauris Kaplinski
+ * Copyright (C) 2001 Ximian, Inc.
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#include "uri-references.h"
+
+#include <iostream>
+#include <cstring>
+
+#include <glibmm/miscutils.h>
+#include "live_effects/lpeobject.h"
+#include "bad-uri-exception.h"
+#include "document.h"
+#include "sp-object.h"
+#include "uri.h"
+#include "extract-uri.h"
+#include "sp-tag-use.h"
+
+namespace Inkscape {
+
+URIReference::URIReference(SPObject *owner)
+ : _owner(owner)
+ , _owner_document(nullptr)
+ , _obj(nullptr)
+ , _uri(nullptr)
+{
+ g_assert(_owner != nullptr);
+ /* FIXME !!! attach to owner's destroy signal to clean up in case */
+}
+
+URIReference::URIReference(SPDocument *owner_document)
+ : _owner(nullptr)
+ , _owner_document(owner_document)
+ , _obj(nullptr)
+ , _uri(nullptr)
+{
+ g_assert(_owner_document != nullptr);
+}
+
+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)).
+ *
+ * (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();
+ //allow LPE as owner has any URI attached
+ LivePathEffectObject *lpobj = dynamic_cast<LivePathEffectObject *>(obj);
+ if (!owner || lpobj)
+ return true;
+
+ while (owner->cloned) {
+ if(!owner->clone_original)//happens when the clone is existing and linking to something, even before the original objects exists.
+ //for instance, it can happen when you paste a filtered object in a already cloned group: The construction of the
+ //clone representation of the filtered object will finish before the original object, so the cloned repr will
+ //have to _accept the filter even though the original does not exist yet. In that case, we'll accept iff the parent of the
+ //original can accept it: loops caused by other relations than parent-child would be prevented when created on their base object.
+ //Fixes bug 1636533.
+ owner = owner->parent;
+ else
+ owner = owner->clone_original;
+ }
+ // once we have the "original" object (hopefully) we look at who is referencing it
+ if (obj == owner)
+ return false;
+ 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)
+{
+ SPDocument *document = nullptr;
+
+ // 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 const *filename = uri.getPath() ? uri.getPath() : "";
+ 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) {
+ char const *base = document->getDocumentBase();
+ auto absuri = URI::from_href_and_basedir(uri.str().c_str(), base);
+ std::string path;
+
+ try {
+ path = absuri.toNativeFilename();
+ } catch (const Glib::Error &e) {
+ g_warning("%s", e.what().c_str());
+ }
+
+ if (!path.empty()) {
+ document = document->createChildDoc(path);
+ } else {
+ document = nullptr;
+ }
+ }
+ if (!document) {
+ g_warning("Can't get document for referenced URI: %s", filename);
+ return;
+ }
+
+ 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 = nullptr;
+ 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);
+}
+
+bool URIReference::try_attach(char const *uri)
+{
+ if (uri && uri[0]) {
+ try {
+ attach(Inkscape::URI(uri));
+ return true;
+ } catch (Inkscape::BadURIException &e) {
+ g_warning("%s", e.what());
+ }
+ }
+ detach();
+ return false;
+}
+
+void URIReference::detach()
+{
+ _connection.disconnect();
+ delete _uri;
+ _uri = nullptr;
+ _setObject(nullptr);
+}
+
+void URIReference::_setObject(SPObject *obj)
+{
+ if (obj && !_acceptObject(obj)) {
+ obj = nullptr;
+ }
+
+ if (obj == _obj)
+ return;
+
+ SPObject *old_obj = _obj;
+ _obj = obj;
+
+ _release_connection.disconnect();
+ if (_obj && (!_owner || !_owner->cloned)) {
+ _obj->hrefObject(_owner);
+ _release_connection = _obj->connectRelease(sigc::mem_fun(*this, &URIReference::_release));
+ }
+ _changed_signal.emit(old_obj, _obj);
+ if (old_obj && (!_owner || !_owner->cloned)) {
+ /* release the old object _after_ the signal emission */
+ old_obj->unhrefObject(_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(nullptr);
+}
+
+} /* namespace Inkscape */
+
+
+
+SPObject *sp_css_uri_reference_resolve(SPDocument *document, const gchar *uri)
+{
+ SPObject *ref = nullptr;
+
+ if (document && uri && (strncmp(uri, "url(", 4) == 0)) {
+ auto trimmed = extract_uri(uri);
+ if (!trimmed.empty()) {
+ ref = sp_uri_reference_resolve(document, trimmed.c_str());
+ }
+ }
+
+ return ref;
+}
+
+SPObject *sp_uri_reference_resolve(SPDocument *document, const gchar *uri)
+{
+ SPObject *ref = nullptr;
+
+ 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 :