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/*
* This file is part of libdom.
* Licensed under the MIT License,
* http://www.opensource.org/licenses/mit-license.php
* Copyright 2021 Michael Drake <tlsa@netsurf-browser.org>
*/
/** \file
* This is an API for walking a loaded DOM.
*/
#include <dom/dom.h>
#include <dom/walk.h>
/**
* Wrapper for calling client callback.
*
* \param[in] mask Mask of stages to enable callback for.
* \param[in] stage Whether the \ref node is being entered or left.
* \param[in] node The node being walked.
* \param[in] cb The client callback function.
* \param[in] ctx The client's private data.
* \param[out] cmd_out Walk instruction from client.
* \return false for early termination of walk, true otherwise.
*/
static inline dom_exception dom_walk__cb(
enum dom_walk_enable mask,
enum dom_walk_stage stage,
dom_node *node,
dom_walk_cb cb,
void *ctx,
enum dom_walk_cmd *cmd_out)
{
if ((1 << stage) & mask) {
dom_node_type type;
dom_exception exc;
exc = dom_node_get_node_type(node, &type);
if (exc != DOM_NO_ERR) {
return exc;
}
*cmd_out = cb(stage, type, node, ctx);
}
return DOM_NO_ERR;
}
/* exported interface documented in include/dom/walk.h */
dom_exception libdom_treewalk(
enum dom_walk_enable mask,
dom_walk_cb cb,
dom_node *root,
void *ctx)
{
dom_node *node;
dom_exception exc;
enum dom_walk_cmd cmd = DOM_WALK_CMD_CONTINUE;
node = dom_node_ref(root);
while (cmd != DOM_WALK_CMD_ABORT) {
dom_node *next = NULL;
if (cmd != DOM_WALK_CMD_SKIP) {
exc = dom_node_get_first_child(node, &next);
if (exc != DOM_NO_ERR) {
dom_node_unref(node);
break;
}
}
if (next != NULL) {
dom_node_unref(node);
node = next;
} else {
/* No children; siblings & ancestor's siblings */
while (node != root) {
exc = dom_walk__cb(mask, DOM_WALK_STAGE_LEAVE,
node, cb, ctx, &cmd);
if (exc != DOM_NO_ERR ||
cmd == DOM_WALK_CMD_ABORT) {
dom_node_unref(node);
return exc;
}
exc = dom_node_get_next_sibling(node, &next);
if (exc != DOM_NO_ERR) {
dom_node_unref(node);
node = NULL;
break;
}
if (next != NULL) {
/* Found next sibling. */
break;
}
exc = dom_node_get_parent_node(node, &next);
if (exc != DOM_NO_ERR) {
dom_node_unref(node);
return exc;
}
dom_node_unref(node);
node = next;
}
if (node == root) {
break;
}
dom_node_unref(node);
node = next;
}
assert(node != NULL);
assert(node != root);
exc = dom_walk__cb(mask, DOM_WALK_STAGE_ENTER, node,
cb, ctx, &cmd);
if (exc != DOM_NO_ERR) {
return exc;
}
}
dom_node_unref(node);
return DOM_NO_ERR;
}
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