netsurf/utils/libdom.c

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/*
* Copyright 2012 Vincent Sanders <vince@netsurf-browser.org>
*
* This file is part of NetSurf, http://www.netsurf-browser.org/
*
* NetSurf is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* NetSurf 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/** \file
* libdom utilities (implementation).
*/
#include <assert.h>
#include "utils/libdom.h"
/* exported interface documented in libdom.h */
bool libdom_treewalk(dom_node *root,
bool (*callback)(dom_node *node, dom_string *name, void *ctx),
void *ctx)
{
dom_node *node;
bool result = true;;
node = dom_node_ref(root); /* tree root */
while (node != NULL) {
dom_node *next = NULL;
dom_node_type type;
dom_string *name;
dom_exception exc;
exc = dom_node_get_first_child(node, &next);
if (exc != DOM_NO_ERR) {
dom_node_unref(node);
break;
}
if (next != NULL) { /* 1. children */
dom_node_unref(node);
node = next;
} else {
exc = dom_node_get_next_sibling(node, &next);
if (exc != DOM_NO_ERR) {
dom_node_unref(node);
break;
}
if (next != NULL) { /* 2. siblings */
dom_node_unref(node);
node = next;
} else { /* 3. ancestor siblings */
while (node != NULL) {
exc = dom_node_get_next_sibling(node,
&next);
if (exc != DOM_NO_ERR) {
dom_node_unref(node);
node = NULL;
break;
}
if (next != NULL) {
dom_node_unref(next);
break;
}
exc = dom_node_get_parent_node(node,
&next);
if (exc != DOM_NO_ERR) {
dom_node_unref(node);
node = NULL;
break;
}
dom_node_unref(node);
node = next;
}
if (node == NULL)
break;
exc = dom_node_get_next_sibling(node, &next);
if (exc != DOM_NO_ERR) {
dom_node_unref(node);
break;
}
dom_node_unref(node);
node = next;
}
}
assert(node != NULL);
exc = dom_node_get_node_type(node, &type);
if ((exc != DOM_NO_ERR) || (type != DOM_ELEMENT_NODE))
continue;
exc = dom_node_get_node_name(node, &name);
if (exc != DOM_NO_ERR)
continue;
result = callback(node, name, ctx);
dom_string_unref(name);
if (result == false) {
break; /* callback caused early termination */
}
}
return result;
}
/* libdom_treewalk context for libdom_find_element */
struct find_element_ctx {
lwc_string *search;
dom_node *found;
};
/* libdom_treewalk callback for libdom_find_element */
static bool libdom_find_element_callback(dom_node *node, dom_string *name,
void *ctx)
{
struct find_element_ctx *data = ctx;
if (dom_string_caseless_lwc_isequal(name, data->search)) {
/* Found element */
data->found = node;
return false; /* Discontinue search */
}
return true; /* Continue search */
}
/* exported interface documented in libdom.h */
dom_node *libdom_find_element(dom_node *node, lwc_string *element_name)
{
struct find_element_ctx data;
assert(element_name != NULL);
if (node == NULL)
return NULL;
data.search = element_name;
data.found = NULL;
libdom_treewalk(node, libdom_find_element_callback, &data);
return data.found;
}