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/*
* This file is part of LibNSLayout
* Licensed under the ISC License, http://opensource.org/licenses/ISC
* Copyright 2015 Michael Drake <tlsa@netsurf-browser.org>
*/
/** \file src/dom/watcher.c
* Implementation of DOM mutation watching.
*
* TODO: LibDOM mutation event listeners are really slow.
* Need to find a better way to get DOM change notifications.
* LibDOM probably needs to gain Mutation Observer support, or
* gain a LibDOM-specific extension API.
*/
#include <stdio.h>
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include "libnslayout/nslayout.h"
#include "dom/debug.h"
#include "dom/watcher.h"
#include "util/dom-str.h"
#include "util/util.h"
/**
* A dom watcher object
*/
struct nsl_dom_watcher {
dom_document *document;
dom_event_listener *listener; /**< DOM event listener object */
};
/**
* LibDOM event handler
*
* \param[in] evt The LibDOM event object
* \param[in] pw Pointer to our dom watcher object
*/
static void nsl__dom_event_handler(struct dom_event *evt, void *pw)
{
const struct nsl_dom_watcher *watcher = pw;
UNUSED(watcher);
nsl_dom_debug_dump_event(evt);
/* TODO: Based on event type:
* 1. call to do (re)selection:
* a. all nodes?
* b. just this node?
* 2. call to update layout, if needed.
*/
}
/**
* Destroy a DOM document's event listener
*
* \param[in] listener The listener to destroy
* \param[in] document The document that the listener was registerd for.
* \return NSLAYOUT_OK on success, appropriate error otherwise.
*/
static nslayout_error nsl__dom_listener_destroy(
dom_event_listener *listener,
dom_document *document)
{
dom_exception exc;
/* Passing NULL as type, removes listener for all event types. */
exc = dom_event_target_remove_event_listener(
document, NULL, listener, false);
if (exc != DOM_NO_ERR) {
return NSL_DOM_ERR(exc);
}
dom_event_listener_unref(listener);
return NSLAYOUT_OK;
}
/**
* Create a dom event listener.
*
* \param[out] listener_out Returns a dom listener for watcher's document.
* \param[in] watcher DOM watcher object that listener is used for.
* \return NSLAYOUT_OK on success, appropriate error otherwise.
*/
static nslayout_error nsl__dom_listener_create(
dom_event_listener **listener_out,
const struct nsl_dom_watcher *watcher)
{
dom_event_listener *listener;
dom_exception exc;
/* Create listener */
exc = dom_event_listener_create(nsl__dom_event_handler,
(void *) watcher, &listener);
if (exc != DOM_NO_ERR) {
goto error;
}
/* Set the event types it should listen to */
exc = dom_event_target_add_event_listener(watcher->document,
nsl_dom_str_node_inserted, listener, false);
if (exc != DOM_NO_ERR) {
goto error;
}
exc = dom_event_target_add_event_listener(watcher->document,
nsl_dom_str_subtree_modified, listener, false);
if (exc != DOM_NO_ERR) {
goto error;
}
exc = dom_event_target_add_event_listener(watcher->document,
nsl_dom_str_node_removed, listener, false);
if (exc != DOM_NO_ERR) {
goto error;
}
exc = dom_event_target_add_event_listener(watcher->document,
nsl_dom_str_attr_modified, listener, false);
if (exc != DOM_NO_ERR) {
goto error;
}
exc = dom_event_target_add_event_listener(watcher->document,
nsl_dom_str_characterdata_modified, listener, false);
if (exc != DOM_NO_ERR) {
goto error;
}
*listener_out = listener;
return NSLAYOUT_OK;
error:
nsl__dom_listener_destroy(listener, watcher->document);
return NSL_DOM_ERR(exc);
}
/* Exported function, documented in src/dom/watcher.h */
nslayout_error nsl_dom_watcher_create(
struct nsl_dom_watcher **watcher_out,
dom_document *document)
{
struct nsl_dom_watcher *watcher;
nslayout_error err;
watcher = malloc(sizeof(*watcher));
if (watcher == NULL) {
return NSLAYOUT_NO_MEM;
}
watcher->document = document;
err = nsl__dom_listener_create(&watcher->listener, watcher);
if (err != NSLAYOUT_OK) {
free(watcher);
return err;
}
*watcher_out = watcher;
return NSLAYOUT_OK;
}
/* Exported function, documented in src/dom/watcher.h */
nslayout_error nsl_dom_watcher_destroy(
struct nsl_dom_watcher *watcher)
{
nsl__dom_listener_destroy(watcher->listener, watcher->document);
free(watcher);
return NSLAYOUT_OK;
}
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