netsurf/render/box_construct.c

/*
 * This file is part of NetSurf, http://netsurf.sourceforge.net/
 * Licensed under the GNU General Public License,
 *                http://www.opensource.org/licenses/gpl-license
 * Copyright 2005 James Bursa <bursa@users.sourceforge.net>
 * Copyright 2003 Phil Mellor <monkeyson@users.sourceforge.net>
 * Copyright 2005 John M Bell <jmb202@ecs.soton.ac.uk>
 */

/** \file
 * Conversion of XML tree to box tree (implementation).
 */

#include <assert.h>
#include <ctype.h>
#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include "libxml/HTMLparser.h"
#include "netsurf/utils/config.h"
#include "netsurf/content/content.h"
#include "netsurf/css/css.h"
#include "netsurf/desktop/options.h"
#include "netsurf/render/box.h"
#include "netsurf/render/form.h"
#include "netsurf/render/html.h"
#ifdef riscos
#include "netsurf/desktop/gui.h"
#endif
#define NDEBUG
#include "netsurf/utils/log.h"
#include "netsurf/utils/messages.h"
#include "netsurf/utils/talloc.h"
#include "netsurf/utils/url.h"
#include "netsurf/utils/utils.h"


/** MultiLength, as defined by HTML 4.01. */
struct box_multi_length {
	enum { LENGTH_PX, LENGTH_PERCENT, LENGTH_RELATIVE } type;
	float value;
};


static const content_type image_types[] = {
#ifdef WITH_JPEG
	CONTENT_JPEG,
#endif
#ifdef WITH_GIF
	CONTENT_GIF,
#endif
#ifdef WITH_PNG
	CONTENT_PNG,
#endif
#ifdef WITH_MNG
	CONTENT_JNG,
	CONTENT_MNG,
#endif
#ifdef WITH_SPRITE
	CONTENT_SPRITE,
#endif
#ifdef WITH_DRAW
	CONTENT_DRAW,
#endif
	CONTENT_UNKNOWN };

#define MAX_SPAN (100)


static bool convert_xml_to_box(xmlNode *n, struct content *content,
		struct css_style *parent_style,
		struct box *parent, struct box **inline_container,
		char *href, char *title);
bool box_construct_element(xmlNode *n, struct content *content,
		struct css_style *parent_style,
		struct box *parent, struct box **inline_container,
		char *href, char *title);
bool box_construct_text(xmlNode *n, struct content *content,
		struct css_style *parent_style,
		struct box *parent, struct box **inline_container,
		char *href, char *title);
static struct css_style * box_get_style(struct content *c,
		struct css_style *parent_style,
		xmlNode *n);
static void box_solve_display(struct css_style *style, bool root);
static void box_set_cellpadding(struct box *box, int value);
static void box_set_table_border(struct box *box, int value, colour color);
static void box_text_transform(char *s, unsigned int len,
		css_text_transform tt);
#define BOX_SPECIAL_PARAMS xmlNode *n, struct content *content, \
		struct box *box, bool *convert_children
static bool box_a(BOX_SPECIAL_PARAMS);
static bool box_body(BOX_SPECIAL_PARAMS);
static bool box_br(BOX_SPECIAL_PARAMS);
static bool box_image(BOX_SPECIAL_PARAMS);
static bool box_form(BOX_SPECIAL_PARAMS);
static bool box_textarea(BOX_SPECIAL_PARAMS);
static bool box_select(BOX_SPECIAL_PARAMS);
static bool box_input(BOX_SPECIAL_PARAMS);
static bool box_input_text(BOX_SPECIAL_PARAMS, bool password);
static bool box_button(BOX_SPECIAL_PARAMS);
static bool box_frameset(BOX_SPECIAL_PARAMS);
static bool box_select_add_option(struct form_control *control, xmlNode *n);
static bool box_object(BOX_SPECIAL_PARAMS);
static bool box_embed(BOX_SPECIAL_PARAMS);
/*static bool box_applet(BOX_SPECIAL_PARAMS);*/
static bool box_iframe(BOX_SPECIAL_PARAMS);
static bool box_get_attribute(xmlNode *n, const char *attribute,
		void *context, char **value);
static bool box_extract_link(const char *rel, const char *base, char **result);
static struct box_multi_length *box_parse_multi_lengths(const char *s,
		unsigned int *count, void *context);


/* element_table must be sorted by name */
struct element_entry {
	char name[10];   /* element type */
	bool (*convert)(BOX_SPECIAL_PARAMS);
};
static const struct element_entry element_table[] = {
	{"a", box_a},
/*	{"applet", box_applet},*/
	{"body", box_body},
	{"br", box_br},
	{"button", box_button},
	{"embed", box_embed},
	{"form", box_form},
	{"frameset", box_frameset},
	{"iframe", box_iframe},
	{"img", box_image},
	{"input", box_input},
	{"object", box_object},
	{"select", box_select},
	{"textarea", box_textarea}
};
#define ELEMENT_TABLE_COUNT (sizeof(element_table) / sizeof(element_table[0]))


/**
 * Construct a box tree from an xml tree and stylesheets.
 *
 * \param  n  xml tree
 * \param  c  content of type CONTENT_HTML to construct box tree in
 * \return  true on success, false on memory exhaustion
 */

bool xml_to_box(xmlNode *n, struct content *c)
{
	struct box root;
	struct box *inline_container = 0;

	assert(c->type == CONTENT_HTML);

	root.type = BOX_BLOCK;
	root.style = NULL;
	root.next = NULL;
	root.prev = NULL;
	root.children = NULL;
	root.last = NULL;
	root.parent = NULL;
	root.float_children = NULL;
	root.next_float = NULL;

	c->data.html.style = talloc_memdup(c, &css_base_style,
			sizeof css_base_style);
	if (!c->data.html.style)
		return false;
	c->data.html.style->font_size.value.length.value =
			option_font_size * 0.1;

	c->data.html.object_count = 0;
	c->data.html.object = 0;

	if (!convert_xml_to_box(n, c, c->data.html.style, &root,
			&inline_container, 0, 0))
		return false;
	if (!box_normalise_block(&root, c))
		return false;

	c->data.html.layout = root.children;
	c->data.html.layout->parent = NULL;

	return true;
}


/* mapping from CSS display to box type
 * this table must be in sync with css/css_enums */
static const box_type box_map[] = {
	0, /*CSS_DISPLAY_INHERIT,*/
	BOX_INLINE, /*CSS_DISPLAY_INLINE,*/
	BOX_BLOCK, /*CSS_DISPLAY_BLOCK,*/
	BOX_BLOCK, /*CSS_DISPLAY_LIST_ITEM,*/
	BOX_INLINE, /*CSS_DISPLAY_RUN_IN,*/
	BOX_INLINE_BLOCK, /*CSS_DISPLAY_INLINE_BLOCK,*/
	BOX_TABLE, /*CSS_DISPLAY_TABLE,*/
	BOX_TABLE, /*CSS_DISPLAY_INLINE_TABLE,*/
	BOX_TABLE_ROW_GROUP, /*CSS_DISPLAY_TABLE_ROW_GROUP,*/
	BOX_TABLE_ROW_GROUP, /*CSS_DISPLAY_TABLE_HEADER_GROUP,*/
	BOX_TABLE_ROW_GROUP, /*CSS_DISPLAY_TABLE_FOOTER_GROUP,*/
	BOX_TABLE_ROW, /*CSS_DISPLAY_TABLE_ROW,*/
	BOX_INLINE, /*CSS_DISPLAY_TABLE_COLUMN_GROUP,*/
	BOX_INLINE, /*CSS_DISPLAY_TABLE_COLUMN,*/
	BOX_TABLE_CELL, /*CSS_DISPLAY_TABLE_CELL,*/
	BOX_INLINE /*CSS_DISPLAY_TABLE_CAPTION,*/
};


/**
 * Recursively construct a box tree from an xml tree and stylesheets.
 *
 * \param  n             fragment of xml tree
 * \param  content       content of type CONTENT_HTML that is being processed
 * \param  parent_style  style at this point in xml tree
 * \param  parent        parent in box tree
 * \param  inline_container  current inline container box, or 0, updated to
 *                       new current inline container on exit
 * \param  status        status for forms etc.
 * \return  true on success, false on memory exhaustion
 */

bool convert_xml_to_box(xmlNode *n, struct content *content,
		struct css_style *parent_style,
		struct box *parent, struct box **inline_container,
		char *href, char *title)
{
	switch (n->type) {
	case XML_ELEMENT_NODE:
		return box_construct_element(n, content, parent_style, parent,
				inline_container, href, title);
	case XML_TEXT_NODE:
		return box_construct_text(n, content, parent_style, parent,
				inline_container, href, title);
	default:
		/* not an element or text node: ignore it (eg. comment) */
		return true;
	}
}


/**
 * Construct the box tree for an XML element.
 *
 * \param  n             XML node of type XML_ELEMENT_NODE
 * \param  content       content of type CONTENT_HTML that is being processed
 * \param  parent_style  style at this point in xml tree
 * \param  parent        parent in box tree
 * \param  inline_container  current inline container box, or 0, updated to
 *                       new current inline container on exit
 * \param  status        status for forms etc.
 * \return  true on success, false on memory exhaustion
 */

bool box_construct_element(xmlNode *n, struct content *content,
		struct css_style *parent_style,
		struct box *parent, struct box **inline_container,
		char *href, char *title)
{
	bool convert_children = true;
	char *id = 0;
	char *s;
	struct box *box = 0;
	struct box *inline_container_c;
	struct css_style *style = 0;
	struct element_entry *element;
	colour border_color;
	xmlChar *title0;
	xmlNode *c;

	assert(n);
	assert(n->type == XML_ELEMENT_NODE);
	assert(parent_style);
	assert(parent);
	assert(inline_container);

	gui_multitask();

	style = box_get_style(content, parent_style, n);
	if (!style)
		return false;
	if (style->display == CSS_DISPLAY_NONE) {
		talloc_free(style);
		return true;
	}

	/* extract title attribute, if present */
	if ((title0 = xmlGetProp(n, (const xmlChar *) "title"))) {
		char *title1 = squash_whitespace(title0);
		xmlFree(title0);
		if (!title1)
			return false;
		title = talloc_strdup(content, title1);
		free(title1);
		if (!title)
			return false;
	}

	/* extract id attribute, if present */
	if (!box_get_attribute(n, "id", content, &id))
		return false;

	/* create box for this element */
	box = box_create(style, href, title, id, content);
	if (!box)
		return false;
	/* set box type from style */
	box->type = box_map[style->display];

	/* special elements */
	element = bsearch((const char *) n->name, element_table,
			ELEMENT_TABLE_COUNT, sizeof(element_table[0]),
			(int (*)(const void *, const void *)) strcmp);
	if (element) {
		/* a special convert function exists for this element */
		if (!element->convert(n, content, box, &convert_children))
			return false;
		href = box->href;
	}

	if (!*inline_container &&
			(box->type == BOX_INLINE ||
			box->type == BOX_BR ||
			box->type == BOX_INLINE_BLOCK ||
			style->float_ == CSS_FLOAT_LEFT ||
			style->float_ == CSS_FLOAT_RIGHT)) {
		/* this is the first inline in a block: make a container */
		*inline_container = box_create(0, 0, 0, 0, content);
		if (!*inline_container)
			return false;
		(*inline_container)->type = BOX_INLINE_CONTAINER;
		box_add_child(parent, *inline_container);
	}

	if (box->type == BOX_INLINE || box->type == BOX_BR) {
		/* inline box: add to tree and recurse */
		box_add_child(*inline_container, box);
		for (c = n->children; convert_children && c; c = c->next)
			if (!convert_xml_to_box(c, content, style, parent,
					inline_container, href, title))
				return false;
	} else if (box->type == BOX_INLINE_BLOCK) {
		/* inline block box: add to tree and recurse */
		box_add_child(*inline_container, box);
		inline_container_c = 0;
		for (c = n->children; convert_children && c; c = c->next)
			if (!convert_xml_to_box(c, content, style, box,
					&inline_container_c, href, title))
				return false;
	} else {
		if (style->float_ == CSS_FLOAT_LEFT ||
				style->float_ == CSS_FLOAT_RIGHT) {
			/* float: insert a float box between the parent and
			 * current node */
			assert(style->float_ == CSS_FLOAT_LEFT ||
					style->float_ == CSS_FLOAT_RIGHT);
			parent = box_create(0, href, title, 0, content);
			if (!parent)
				return false;
			if (style->float_ == CSS_FLOAT_LEFT)
				parent->type = BOX_FLOAT_LEFT;
			else
				parent->type = BOX_FLOAT_RIGHT;
			box_add_child(*inline_container, parent);
			if (box->type == BOX_INLINE ||
					box->type == BOX_INLINE_BLOCK)
				box->type = BOX_BLOCK;
		}

		/* non-inline box: add to tree and recurse */
		box_add_child(parent, box);
		inline_container_c = 0;
		for (c = n->children; convert_children && c; c = c->next)
			if (!convert_xml_to_box(c, content, style, box,
					&inline_container_c, href, title))
				return false;
		if (style->float_ == CSS_FLOAT_NONE)
			/* new inline container unless this is a float */
			*inline_container = 0;
	}

	/* misc. attributes that can't be handled in box_get_style() */
	if ((s = (char *) xmlGetProp(n, (const xmlChar *) "colspan"))) {
		box->columns = strtol(s, NULL, 10);
		if (MAX_SPAN < box->columns)
			box->columns = 1;
		xmlFree(s);
	}
	if ((s = (char *) xmlGetProp(n, (const xmlChar *) "rowspan"))) {
		box->rows = strtol(s, NULL, 10);
		if (MAX_SPAN < box->rows)
			box->rows = 1;
		xmlFree(s);
	}
	if (strcmp((const char *) n->name, "table") == 0) {
	  	border_color = 0x888888;	/* default colour */
	  	if ((s = (char *) xmlGetProp(n,
				(const xmlChar *) "cellpadding"))) {
			int value = atoi(s);
			if (!strrchr(s, '%') && 0 < value)	/* % not implemented */
				box_set_cellpadding(box, value);
			xmlFree(s);
		}
	  	if ((s = (char *) xmlGetProp(n,
					(const xmlChar *) "bordercolor"))) {
			unsigned int r, g, b;
			if (s[0] == '#' && sscanf(s + 1, "%2x%2x%2x", &r, &g, &b) == 3)
				border_color = (b << 16) | (g << 8) | r;
			else if (s[0] != '#')
				border_color = named_colour(s);
			xmlFree(s);
		}
	  	if ((s = (char *) xmlGetProp(n,
				(const xmlChar *) "border"))) {
			int value = atoi(s);
			if (!strrchr(s, '%') && 0 < value)	/* % not implemented */
				box_set_table_border(box, value, border_color);
			xmlFree(s);
		}
	}

	/* fetch any background image for this box */
	if (style->background_image.type == CSS_BACKGROUND_IMAGE_URI) {
		if (!html_fetch_object(content, style->background_image.uri,
				box, image_types, content->available_width,
				1000, true))
			return false;
	}

	return true;
}


/**
 * Construct the box tree for an XML text node.
 *
 * \param  n             XML node of type XML_TEXT_NODE
 * \param  content       content of type CONTENT_HTML that is being processed
 * \param  parent_style  style at this point in xml tree
 * \param  parent        parent in box tree
 * \param  inline_container  current inline container box, or 0, updated to
 *                       new current inline container on exit
 * \param  status        status for forms etc.
 * \return  true on success, false on memory exhaustion
 */

bool box_construct_text(xmlNode *n, struct content *content,
		struct css_style *parent_style,
		struct box *parent, struct box **inline_container,
		char *href, char *title)
{
	struct box *box = 0;

	assert(n);
	assert(n->type == XML_TEXT_NODE);
	assert(parent_style);
	assert(parent);
	assert(inline_container);

	if (parent_style->white_space == CSS_WHITE_SPACE_NORMAL ||
			 parent_style->white_space == CSS_WHITE_SPACE_NOWRAP) {
		char *text = squash_whitespace(n->content);
		if (!text)
			return false;

		/* if the text is just a space, combine it with the preceding
		 * text node, if any */
		if (text[0] == ' ' && text[1] == 0) {
			if (*inline_container) {
				assert((*inline_container)->last != 0);
				(*inline_container)->last->space = 1;
			}
			free(text);
			return true;
		}

		if (!*inline_container) {
			/* this is the first inline node: make a container */
			*inline_container = box_create(0, 0, 0, 0, content);
			if (!*inline_container)	{
				free(text);
				return false;
			}
			(*inline_container)->type = BOX_INLINE_CONTAINER;
			box_add_child(parent, *inline_container);
		}

		box = box_create(parent_style, href, title, 0, content);
		if (!box) {
			free(text);
			return false;
		}
		box->text = talloc_strdup(content, text);
		free(text);
		if (!box->text)
			return false;
		box->length = strlen(box->text);
		/* strip ending space char off */
		if (box->length > 1 && text[box->length - 1] == ' ') {
			box->space = 1;
			box->length--;
		}
		if (parent_style->text_transform != CSS_TEXT_TRANSFORM_NONE)
			box_text_transform(box->text, box->length,
					parent_style->text_transform);
		if (parent_style->white_space == CSS_WHITE_SPACE_NOWRAP) {
			unsigned int i;
			for (i = 0; i != box->length && text[i] != ' '; ++i)
				; /* no body */
			if (i != box->length) {
				/* there is a space in text block and we
				 * want all spaces to be converted to NBSP
				 */
				/*box->text = cnv_space2nbsp(text);
				if (!box->text) {
					free(text);
					goto no_memory;
				}
				box->length = strlen(box->text);*/
			}
		}

		box_add_child(*inline_container, box);
		if (box->text[0] == ' ') {
			box->length--;
			memmove(box->text, &box->text[1], box->length);
			if (box->prev != NULL)
				box->prev->space = 1;
		}

	} else {
		/* white-space: pre */
		char *text = cnv_space2nbsp(n->content);
		char *current;
		/* note: pre-wrap/pre-line are unimplemented */
		assert(parent_style->white_space == CSS_WHITE_SPACE_PRE ||
			parent_style->white_space ==
						CSS_WHITE_SPACE_PRE_LINE ||
			parent_style->white_space ==
						CSS_WHITE_SPACE_PRE_WRAP);
		if (!text)
			return false;
		if (parent_style->text_transform != CSS_TEXT_TRANSFORM_NONE)
			box_text_transform(text, strlen(text),
					parent_style->text_transform);
		current = text;
		do {
			size_t len = strcspn(current, "\r\n");
			char old = current[len];
			current[len] = 0;
			if (!*inline_container) {
				*inline_container = box_create(0, 0, 0, 0,
						content);
				if (!*inline_container) {
					free(text);
					return false;
				}
				(*inline_container)->type =
						BOX_INLINE_CONTAINER;
				box_add_child(parent, *inline_container);
			}
			box = box_create(parent_style, href, title, 0, content);
			if (!box) {
				free(text);
				return false;
			}
			box->type = BOX_INLINE;
			box->text = talloc_strdup(content, current);
			if (!box->text) {
				free(text);
				return false;
			}
			box->length = strlen(box->text);
			box_add_child(*inline_container, box);
			current[len] = old;
			current += len;
			if (current[0] == '\r' && current[1] == '\n') {
				current += 2;
				*inline_container = 0;
			} else if (current[0] != 0) {
				current++;
				*inline_container = 0;
			}
		} while (*current);
		free(text);
	}

	return true;
}


/**
 * Get the style for an element.
 *
 * \param  c             content of type CONTENT_HTML that is being processed
 * \param  parent_style  style at this point in xml tree
 * \param  n             node in xml tree
 * \return  the new style, or 0 on memory exhaustion
 *
 * The style is collected from three sources:
 *  1. any styles for this element in the document stylesheet(s)
 *  2. non-CSS HTML attributes
 *  3. the 'style' attribute
 */

struct css_style * box_get_style(struct content *c,
		struct css_style *parent_style,
		xmlNode *n)
{
	char *s;
	unsigned int i;
	unsigned int stylesheet_count = c->data.html.stylesheet_count;
	struct content **stylesheet = c->data.html.stylesheet_content;
	struct css_style *style;
	struct css_style *style_new;
	char *url;
	url_func_result res;

	style = talloc_memdup(c, parent_style, sizeof *style);
	if (!style)
		return 0;

	style_new = talloc_memdup(c, &css_blank_style, sizeof *style_new);
	if (!style_new)
		return 0;

	for (i = 0; i != stylesheet_count; i++) {
		if (stylesheet[i]) {
			assert(stylesheet[i]->type == CONTENT_CSS);
			css_get_style(stylesheet[i], n, style_new);
		}
	}
	css_cascade(style, style_new);

	/* style_new isn't needed past this point */
	talloc_free(style_new);

	/* This property only applies to the body element, if you believe
	 * the spec. Many browsers seem to allow it on other elements too,
	 * so let's be generic ;) */
	if ((s = (char *) xmlGetProp(n, (const xmlChar *) "background"))) {
		res = url_join(s, c->data.html.base_url, &url);
		xmlFree(s);
		if (res == URL_FUNC_NOMEM) {
			return 0;
		} else if (res == URL_FUNC_OK) {
			/* if url is equivalent to the parent's url,
			 * we've got infinite inclusion: ignore */
			if (strcmp(url, c->data.html.base_url) == 0)
				free(url);
			else {
				style->background_image.type =
						CSS_BACKGROUND_IMAGE_URI;
				style->background_image.uri = talloc_strdup(
						c, url);
				free(url);
				if (!style->background_image.uri)
					return 0;
			}
		}
	}

	if ((s = (char *) xmlGetProp(n, (const xmlChar *) "bgcolor"))) {
		unsigned int r, g, b;
		if (s[0] == '#' && sscanf(s + 1, "%2x%2x%2x", &r, &g, &b) == 3)
			style->background_color = (b << 16) | (g << 8) | r;
		else if (s[0] != '#')
			style->background_color = named_colour(s);
		xmlFree(s);
	}

	if ((s = (char *) xmlGetProp(n, (const xmlChar *) "color"))) {
		unsigned int r, g, b;
		if (s[0] == '#' && sscanf(s + 1, "%2x%2x%2x", &r, &g, &b) == 3)
			style->color = (b << 16) | (g << 8) | r;
		else if (s[0] != '#')
			style->color = named_colour(s);
		xmlFree(s);
	}

	if ((s = (char *) xmlGetProp(n, (const xmlChar *) "height"))) {
		float value = atof(s);
		if (value < 0 || strlen(s) == 0) {
			/* ignore negative values and height="" */
		} else if (strrchr(s, '%')) {
			/* the specification doesn't make clear what
			 * percentage heights mean, so ignore them */
		} else {
			style->height.height = CSS_HEIGHT_LENGTH;
			style->height.length.unit = CSS_UNIT_PX;
			style->height.length.value = value;
		}
		xmlFree(s);
	}

	if (strcmp((const char *) n->name, "input") == 0) {
		if ((s = (char *) xmlGetProp(n, (const xmlChar *) "size"))) {
			int size = atoi(s);
			if (0 < size) {
				char *type = (char *) xmlGetProp(n,
						(const xmlChar *) "type");
				style->width.width = CSS_WIDTH_LENGTH;
				if (!type || strcasecmp(type, "text") == 0 ||
					strcasecmp(type, "password") == 0)
					/* in characters for text, password */
					style->width.value.length.unit =
							CSS_UNIT_EX;
				else if (strcasecmp(type, "file") != 0)
					/* in pixels otherwise; ignore width
					 * on file, because we do them
					 * differently to most browsers */
					style->width.value.length.unit =
							CSS_UNIT_PX;
				style->width.value.length.value = size;
				if (type)
					xmlFree(type);
			}
			xmlFree(s);
		}
	}

	if (strcmp((const char *) n->name, "body") == 0) {
		if ((s = (char *) xmlGetProp(n, (const xmlChar *) "text"))) {
			unsigned int r, g, b;
			if (s[0] == '#' && sscanf(s + 1, "%2x%2x%2x",
					&r, &g, &b) == 3)
				style->color = (b << 16) | (g << 8) | r;
			else if (s[0] != '#')
				style->color = named_colour(s);
			xmlFree(s);
		}
	}

	if ((s = (char *) xmlGetProp(n, (const xmlChar *) "width"))) {
		float value = atof(s);
		if (value < 0 || strlen(s) == 0) {
			/* ignore negative values and width="" */
		} else if (strrchr(s, '%')) {
			style->width.width = CSS_WIDTH_PERCENT;
			style->width.value.percent = value;
		} else {
			style->width.width = CSS_WIDTH_LENGTH;
			style->width.value.length.unit = CSS_UNIT_PX;
			style->width.value.length.value = value;
		}
		xmlFree(s);
	}

	if (strcmp((const char *) n->name, "textarea") == 0) {
		if ((s = (char *) xmlGetProp(n, (const xmlChar *) "rows"))) {
			int value = atoi(s);
			if (0 < value) {
				style->height.height = CSS_HEIGHT_LENGTH;
				style->height.length.unit = CSS_UNIT_EM;
				style->height.length.value = value;
			}
			xmlFree(s);
		}
		if ((s = (char *) xmlGetProp(n, (const xmlChar *) "cols"))) {
			int value = atoi(s);
			if (0 < value) {
				style->width.width = CSS_WIDTH_LENGTH;
				style->width.value.length.unit = CSS_UNIT_EX;
				style->width.value.length.value = value;
			}
			xmlFree(s);
		}
	}

	if (strcmp((const char *) n->name, "table") == 0) {
		if ((s = (char *) xmlGetProp(n,
				(const xmlChar *) "cellspacing"))) {
			if (!strrchr(s, '%')) {		/* % not implemented */
				int value = atoi(s);
				if (0 <= value) {
					style->border_spacing.border_spacing =
						CSS_BORDER_SPACING_LENGTH;
					style->border_spacing.horz.unit =
					style->border_spacing.vert.unit =
							CSS_UNIT_PX;
					style->border_spacing.horz.value =
					style->border_spacing.vert.value =
							value;
				}
			}
		}
	}

	if ((s = (char *) xmlGetProp(n, (const xmlChar *) "style"))) {
		struct css_style *astyle;
		astyle = css_duplicate_style(&css_empty_style);
		if (!astyle) {
			xmlFree(s);
			css_free_style(style);
			return 0;
		}
		css_parse_property_list(c, astyle, s);
		css_cascade(style, astyle);
		css_free_style(astyle);
		xmlFree(s);
	}

	box_solve_display(style, !n->parent);

	return style;
}


/**
 * Calculate 'display' based on 'display', 'position', and 'float', as given
 * by CSS 2.1 9.7.
 *
 * \param  style  style to update
 * \param  root   this is the root element
 */

void box_solve_display(struct css_style *style, bool root)
{
	if (style->display == CSS_DISPLAY_NONE)		/* 1. */
		return;
	else if (style->position == CSS_POSITION_ABSOLUTE ||
			style->position == CSS_POSITION_FIXED)	/* 2. */
		style->float_ = CSS_FLOAT_NONE;
	else if (style->float_ != CSS_FLOAT_NONE)		/* 3. */
		;
	else if (root)						/* 4. */
		;
	else							/* 5. */
		return;

	/* map specified value to computed value using table given in 9.7 */
	if (style->display == CSS_DISPLAY_INLINE_TABLE)
		style->display = CSS_DISPLAY_TABLE;
	else if (style->display == CSS_DISPLAY_LIST_ITEM ||
			style->display == CSS_DISPLAY_TABLE)
		; /* same as specified */
	else
		style->display = CSS_DISPLAY_BLOCK;
}


/**
 * Set the cellpadding on a table.
 *
 * \param  box    box to set cellpadding on
 * \param  value  padding in pixels
 *
 * The descendants of the box are searched for table cells, and the padding is
 * set on each one.
 */

void box_set_cellpadding(struct box *box, int value)
{
	/* The tree is not normalized yet, so accept cells not in rows and
	 * rows not in row groups. */
	struct box *child;
	for (child = box->children; child; child = child->next) {
		switch (child->type) {
		case BOX_TABLE_ROW_GROUP:
		case BOX_TABLE_ROW:
			box_set_cellpadding(child, value);
			break;
		case BOX_TABLE_CELL:
			for (unsigned int i = 0; i != 4; i++) {
				child->style->padding[i].padding =
						CSS_PADDING_LENGTH;
				child->style->padding[i].value.length.value =
						value;
				child->style->padding[i].value.length.unit =
						CSS_UNIT_PX;
			}
			break;
		default:
			break;
	        }
	}
}


/**
 * Set the borders on a table.
 *
 * \param  box    box to set cellpadding on
 * \param  value  border in pixels
 *
 * The descendants of the box are searched for table cells, and the border is
 * set on each one.
 */

void box_set_table_border(struct box *box, int value, colour color)
{
	struct box *child;

	if (box->type == BOX_TABLE) {
		for (unsigned int i = 0; i != 4; i++) {
			box->style->border[i].color = color;
			box->style->border[i].width.width =
					CSS_BORDER_WIDTH_LENGTH;
			box->style->border[i].width.value.value =
					value;
			box->style->border[i].width.value.unit =
					CSS_UNIT_PX;
			box->style->border[i].style =
					CSS_BORDER_STYLE_OUTSET;
		}
	}

	/* The tree is not normalized yet, so accept cells not in rows and
	 * rows not in row groups. */
	for (child = box->children; child; child = child->next) {
		switch (child->type) {
		case BOX_TABLE_ROW_GROUP:
		case BOX_TABLE_ROW:
			box_set_table_border(child, value, color);
			break;
		case BOX_TABLE_CELL:
			for (unsigned int i = 0; i != 4; i++) {
				child->style->border[i].color = color;
				child->style->border[i].width.width =
						CSS_BORDER_WIDTH_LENGTH;
				child->style->border[i].width.value.value =
						1;
				child->style->border[i].width.value.unit =
						CSS_UNIT_PX;
				child->style->border[i].style =
						CSS_BORDER_STYLE_INSET;
			}
			break;
		default:
			break;
	        }
	}
}


/**
 * Apply the CSS text-transform property to given text for its ASCII chars.
 *
 * \param  s    string to transform
 * \param  len  length of s
 * \param  tt   transform type
 */

void box_text_transform(char *s, unsigned int len,
		css_text_transform tt)
{
	unsigned int i;
	if (len == 0)
		return;
	switch (tt) {
		case CSS_TEXT_TRANSFORM_UPPERCASE:
			for (i = 0; i < len; ++i)
				if (s[i] < 0x80)
					s[i] = toupper(s[i]);
			break;
		case CSS_TEXT_TRANSFORM_LOWERCASE:
			for (i = 0; i < len; ++i)
				if (s[i] < 0x80)
					s[i] = tolower(s[i]);
			break;
		case CSS_TEXT_TRANSFORM_CAPITALIZE:
			if (s[0] < 0x80)
				s[0] = toupper(s[0]);
			for (i = 1; i < len; ++i)
				if (s[i] < 0x80 && isspace(s[i - 1]))
					s[i] = toupper(s[i]);
			break;
		default:
			break;
	}
}


/**
 * \name  Special case element handlers
 *
 * These functions are called by box_construct_element() when an element is
 * being converted, according to the entries in element_table.
 *
 * The parameters are the xmlNode, the content for the document, and a partly
 * filled in box structure for the element.
 *
 * Return true on success, false on memory exhaustion. Set *convert_children
 * to false if children of this element in the XML tree should be skipped (for
 * example, if they have been processed in some special way already).
 *
 * Elements ordered as in the HTML 4.01 specification. Section numbers in
 * brackets [] refer to the spec.
 *
 * \{
 */

/**
 * Document body [7.5.1].
 */

bool box_body(BOX_SPECIAL_PARAMS)
{
	content->data.html.background_colour = box->style->background_color;
	return true;
}


/**
 * Forced line break [9.3.2].
 */

bool box_br(BOX_SPECIAL_PARAMS)
{
	box->type = BOX_BR;
	return true;
}


/**
 * Anchor [12.2].
 */

bool box_a(BOX_SPECIAL_PARAMS)
{
	bool ok;
	char *url;
	xmlChar *s;

	if ((s = xmlGetProp(n, (const xmlChar *) "href"))) {
		ok = box_extract_link((const char *) s,
				content->data.html.base_url, &url);
		xmlFree(s);
		if (!ok)
			return false;
		if (url) {
			box->href = talloc_strdup(content, url);
			if (!box->href)
				return false;
			free(url);
		}
	}

	/* name and id share the same namespace */
	if (!box_get_attribute(n, "name", content, &box->id))
		return false;

	return true;
}


/**
 * Embedded image [13.2].
 */

bool box_image(BOX_SPECIAL_PARAMS)
{
	bool ok;
	char *s, *url;
	xmlChar *alt, *src;

	/* handle alt text */
	if ((alt = xmlGetProp(n, (const xmlChar *) "alt"))) {
		s = squash_whitespace(alt);
		xmlFree(alt);
		if (!s)
			return false;
		box->text = talloc_strdup(content, s);
		free(s);
		if (!box->text)
			return false;
		box->length = strlen(box->text);
	}

	/* imagemap associated with this image */
	if (!box_get_attribute(n, "usemap", content, &box->usemap))
		return false;
	if (box->usemap && box->usemap[0] == '#')
		box->usemap++;

	/* get image URL */
	if (!(src = xmlGetProp(n, (const xmlChar *) "src")))
		return true;
	if (!box_extract_link((char *) src, content->data.html.base_url, &url))
		return false;
	xmlFree(src);
	if (!url)
		return true;

	/* start fetch */
	ok = html_fetch_object(content, url, box, image_types,
			content->available_width, 1000, false);
	free(url);
	return ok;
}


/**
 * Generic embedded object [13.3].
 */

bool box_object(BOX_SPECIAL_PARAMS)
{
	struct object_params *params;
	struct object_param *param;
	xmlChar *codebase, *classid, *data;
	xmlNode *c;
	struct box *inline_container = 0;

	if (!box_get_attribute(n, "usemap", content, &box->usemap))
		return false;
	if (box->usemap && box->usemap[0] == '#')
		box->usemap++;

	params = talloc(content, struct object_params);
	if (!params)
		return false;
	params->data = 0;
	params->type = 0;
	params->codetype = 0;
	params->codebase = 0;
	params->classid = 0;
	params->params = 0;

	/* codebase, classid, and data are URLs (codebase is the base for the
	 * other two) */
	if ((codebase = xmlGetProp(n, (const xmlChar *) "codebase"))) {
		if (!box_extract_link((char *) codebase,
				content->data.html.base_url, &params->codebase))
			return false;
		xmlFree(codebase);
	}
	if (!params->codebase)
		params->codebase = content->data.html.base_url;

	if ((classid = xmlGetProp(n, (const xmlChar *) "codebase"))) {
		if (!box_extract_link((char *) classid, params->codebase,
				&params->classid))
			return false;
		xmlFree(classid);
	}

	if ((data = xmlGetProp(n, (const xmlChar *) "data"))) {
		if (!box_extract_link((char *) data, params->codebase,
				&params->data))
			return false;
		xmlFree(data);
	}
	if (!params->data)
		/* objects without data are ignored */
		return true;

	/* codetype and type are MIME types */
	if (!box_get_attribute(n, "codetype", params, &params->codetype))
		return false;
	if (!box_get_attribute(n, "type", params, &params->type))
		return false;
	if (params->type && content_lookup(params->type) == CONTENT_OTHER)
		/* can't handle this MIME type */
		return true;

	/* add parameters to linked list */
	for (c = n->children; c; c = c->next) {
		if (c->type != XML_ELEMENT_NODE)
			continue;
		if (strcmp((const char *) c->name, "param") != 0)
			/* The first non-param child is the start of the alt
			 * html. Therefore, we should break out of this loop. */
			break;

		param = talloc(params, struct object_param);
		if (!param)
			return false;
		param->name = 0;
		param->value = 0;
		param->type = 0;
		param->valuetype = 0;
		param->next = 0;

		if (!box_get_attribute(c, "name", param, &param->name))
			return false;
		if (!box_get_attribute(c, "value", param, &param->value))
			return false;
		if (!box_get_attribute(c, "type", param, &param->type))
			return false;
		if (!box_get_attribute(c, "valuetype", param,
				&param->valuetype))
			return false;
		if (!param->valuetype)
			param->valuetype = "data";

		param->next = params->params;
		params->params = param;
	}

	box->object_params = params;

	/* start fetch (MIME type is ok or not specified) */
	if (!html_fetch_object(content, params->data, box, 0,
			content->available_width, 1000, false))
		return false;

	/* convert children and place into fallback */
	for (c = n->children; c; c = c->next) {
		if (!convert_xml_to_box(c, content, box->style, box,
				&inline_container, 0, 0))
			return false;
	}
	box->fallback = box->children;
	box->children = box->last = 0;

	*convert_children = false;
	return true;
}


#if 0 /**
 * "Java applet" [13.4].
 *
 * \todo This needs reworking to be compliant to the spec
 * For now, we simply ignore all applet tags.
 */

struct box_result box_applet(xmlNode *n, struct box_status *status,
		struct css_style *style)
{
	struct box *box;
	struct object_params *po;
	struct object_param *pp = NULL;
	char *s;
	xmlNode *c;

	po = calloc(1, sizeof(struct object_params));
	if (!po)
		return (struct box_result) {0, false, true};

	box = box_create(style, status->href, 0, status->id,
			status->content->data.html.box_pool);
	if (!box) {
		free(po);
		return (struct box_result) {0, false, true};
	}

	/* archive */
	if ((s = (char *) xmlGetProp(n, (const xmlChar *) "archive")) != NULL) {
		/** \todo tokenise this comma separated list */
		LOG(("archive '%s'", s));
		po->data = strdup(s);
		xmlFree(s);
		if (!po->data)
			goto no_memory;
	}
	/* code */
	if ((s = (char *) xmlGetProp(n, (const xmlChar *) "code")) != NULL) {
		LOG(("applet '%s'", s));
		po->classid = strdup(s);
		xmlFree(s);
		if (!po->classid)
			goto no_memory;
	}

	/* object codebase */
	if ((s = (char *) xmlGetProp(n, (const xmlChar *) "codebase")) != NULL) {
		po->codebase = strdup(s);
		LOG(("codebase: %s", s));
		xmlFree(s);
		if (!po->codebase)
			goto no_memory;
	}

	/* parameters
	 * parameter data is stored in a singly linked list.
	 * po->params points to the head of the list.
	 * new parameters are added to the head of the list.
	 */
	for (c = n->children; c != 0; c = c->next) {
		if (c->type != XML_ELEMENT_NODE)
			continue;

		if (strcmp((const char *) c->name, "param") == 0) {
			pp = calloc(1, sizeof(struct object_param));
			if (!pp)
				goto no_memory;

			if ((s = (char *) xmlGetProp(c, (const xmlChar *) "name")) != NULL) {
				pp->name = strdup(s);
				xmlFree(s);
				if (!pp->name)
					goto no_memory;
			}
			if ((s = (char *) xmlGetProp(c, (const xmlChar *) "value")) != NULL) {
				pp->value = strdup(s);
				xmlFree(s);
				if (!pp->value)
					goto no_memory;
			}
			if ((s = (char *) xmlGetProp(c, (const xmlChar *) "type")) != NULL) {
				pp->type = strdup(s);
				xmlFree(s);
				if (!pp->type)
					goto no_memory;
			}
			if ((s = (char *) xmlGetProp(c, (const xmlChar *) "valuetype")) != NULL) {
				pp->valuetype = strdup(s);
				xmlFree(s);
				if (!pp->valuetype)
					goto no_memory;
			} else {
				pp->valuetype = strdup("data");
				if (!pp->valuetype)
					goto no_memory;
			}

			pp->next = po->params;
			po->params = pp;
		} else {
				 /* The first non-param child is the start
				  * of the alt html. Therefore, we should
				  * break out of this loop.
				  */
				break;
		}
	}

	box->object_params = po;

	/* start fetch */
	if (plugin_decode(status->content, box))
		return (struct box_result) {box, false, false};

	return (struct box_result) {box, true, false};

no_memory:
	if (pp && pp != po->params) {
		/* ran out of memory creating parameter struct */
		free(pp->name);
		free(pp->value);
		free(pp->type);
		free(pp->valuetype);
		free(pp);
	}

	box_free_object_params(po);
	box_free_box(box);

	return (struct box_result) {0, false, true};
}
#endif


/**
 * Window subdivision [16.2.1].
 */

bool box_frameset(BOX_SPECIAL_PARAMS)
{
	unsigned int row, col;
	unsigned int rows = 1, cols = 1;
	int object_width, object_height;
	char *s, *s1, *url;
	struct box *row_box;
	struct box *cell_box;
	struct box *frameset_box;
	struct box *object_box;
	struct css_style *style = box->style;
	struct css_style *row_style;
	struct css_style *cell_style;
	struct css_style *object_style;
	struct box_multi_length *row_height = 0, *col_width = 0;
	xmlNode *c;
	url_func_result res;

	box->type = BOX_TABLE;

	/* parse rows and columns */
	if ((s = (char *) xmlGetProp(n, (const xmlChar *) "rows"))) {
		row_height = box_parse_multi_lengths(s, &rows, content);
		xmlFree(s);
		if (!row_height)
			return false;
	}

	if ((s = (char *) xmlGetProp(n, (const xmlChar *) "cols"))) {
		col_width = box_parse_multi_lengths(s, &cols, content);
		xmlFree(s);
		if (!col_width)
			return false;
	}

	LOG(("rows %u, cols %u", rows, cols));

	box->min_width = 1;
	box->max_width = 10000;
	box->col = talloc_array(content, struct column, cols);
	if (!box->col)
		return false;

	if (col_width) {
		for (col = 0; col != cols; col++) {
			if (col_width[col].type == LENGTH_PX) {
				box->col[col].type = COLUMN_WIDTH_FIXED;
				box->col[col].width = col_width[col].value;
			} else if (col_width[col].type == LENGTH_PERCENT) {
				box->col[col].type = COLUMN_WIDTH_PERCENT;
				box->col[col].width = col_width[col].value;
			} else {
				box->col[col].type = COLUMN_WIDTH_RELATIVE;
				box->col[col].width = col_width[col].value;
			}
			box->col[col].min = 1;
			box->col[col].max = 10000;
		}
	} else {
		box->col[0].type = COLUMN_WIDTH_RELATIVE;
		box->col[0].width = 1;
		box->col[0].min = 1;
		box->col[0].max = 10000;
	}

	/* create the frameset table */
	c = n->children;
	for (row = 0; c && row != rows; row++) {
		row_style = talloc_memdup(content, style, sizeof *style);
		if (!row_style)
			return false;
		object_height = 1000;  /** \todo  get available height */
	/*	if (row_height) {
			row_style->height.height = CSS_HEIGHT_LENGTH;
			row_style->height.length.unit = CSS_UNIT_PX;
			if (row_height[row].type == LENGTH_PERCENT)
				row_style->height.length.value = 1000 *
						row_height[row].value / 100;
			else if (row_height[row].type == LENGTH_RELATIVE)
				row_style->height.length.value = 100 *
						row_height[row].value;
			else
				row_style->height.length.value =
						row_height[row].value;
			object_height = row_style->height.length.value;
		}*/
		row_box = box_create(row_style, 0, 0, 0, content);
		if (!row_box)
			return false;

		row_box->type = BOX_TABLE_ROW;
		box_add_child(box, row_box);

		for (col = 0; c && col != cols; col++) {
			while (c && !(c->type == XML_ELEMENT_NODE && (
				strcmp((const char *) c->name, "frame") == 0 ||
				strcmp((const char *) c->name, "frameset") == 0
					)))
				c = c->next;
			if (!c)
				break;

			/* estimate frame width */
			object_width = content->available_width;
			if (col_width && col_width[col].type == LENGTH_PX)
				object_width = col_width[col].value;

			cell_style = talloc_memdup(content, style,
					sizeof *style);
			if (!cell_style)
				return false;
			css_cascade(cell_style, &css_blank_style);
			cell_style->overflow = CSS_OVERFLOW_AUTO;

			cell_box = box_create(cell_style, 0, 0, 0, content);
			if (!cell_box)
				return false;
			cell_box->type = BOX_TABLE_CELL;
			box_add_child(row_box, cell_box);

			if (strcmp((const char *) c->name, "frameset") == 0) {
				LOG(("frameset"));
				frameset_box = box_create(cell_style, 0, 0, 0,
						content);
				if (!frameset_box)
					return false;
				if (!box_frameset(n, content, frameset_box, 0))
					return false;
				box_add_child(cell_box, frameset_box);

				c = c->next;
				continue;
			}

			object_style = talloc_memdup(content, style,
					sizeof *style);
			if (!object_style)
				return false;
			if (col_width && col_width[col].type == LENGTH_PX) {
				object_style->width.width = CSS_WIDTH_LENGTH;
				object_style->width.value.length.unit =
						CSS_UNIT_PX;
				object_style->width.value.length.value =
						object_width;
			}

			object_box = box_create(object_style, 0, 0, 0, content);
			if (!object_box)
				return false;
			object_box->type = BOX_BLOCK;
			box_add_child(cell_box, object_box);

			if (!(s = (char *) xmlGetProp(c,
					(const xmlChar *) "src"))) {
				c = c->next;
				continue;
			}

			s1 = strip(s);
			res = url_join(s1, content->data.html.base_url, &url);
			xmlFree(s);
			/* if url is equivalent to the parent's url,
			 * we've got infinite inclusion. stop it here.
			 * also bail if url_join failed.
			 */
			if (res != URL_FUNC_OK || strcasecmp(url,
					content->data.html.base_url) == 0) {
				LOG(("url_join failed"));
				c = c->next;
				continue;
			}

			LOG(("frame, url '%s'", url));

			if (!html_fetch_object(content, url,
					object_box, 0,
					object_width, object_height, false))
				return false;
			free(url);

			c = c->next;
		}
	}

	talloc_free(row_height);
	talloc_free(col_width);

	style->width.width = CSS_WIDTH_PERCENT;
	style->width.value.percent = 100;

	if (convert_children)
		*convert_children = false;
	return true;
}


/**
 * Inline subwindow [16.5].
 */

bool box_iframe(BOX_SPECIAL_PARAMS)
{
	bool ok;
	char *url;
	xmlChar *src;

	/* get frame URL */
	if (!(src = xmlGetProp(n, (const xmlChar *) "src")))
		return true;
	if (!box_extract_link((char *) src, content->data.html.base_url, &url))
		return false;
	if (!url)
		return true;

	/* start fetch */
	ok = html_fetch_object(content, url, box, 0,
			content->available_width, 1000, false);
	free(url);
	return ok;
}


/**
 * Interactive form [17.3].
 */

bool box_form(BOX_SPECIAL_PARAMS)
{
	char *action, *method, *enctype, *charset;
	form_method fmethod;
	struct form *form;

	if (!(action = (char *) xmlGetProp(n, (const xmlChar *) "action")))
		/* the action attribute is required */
		return true;

	fmethod = method_GET;
	if ((method = (char *) xmlGetProp(n, (const xmlChar *) "method"))) {
		if (strcasecmp(method, "post") == 0) {
			fmethod = method_POST_URLENC;
			if ((enctype = (char *) xmlGetProp(n,
					(const xmlChar *) "enctype"))) {
				if (strcasecmp(enctype,
						"multipart/form-data") == 0)
					fmethod = method_POST_MULTIPART;
				xmlFree(enctype);
			}
		}
		xmlFree(method);
	}

	/* acceptable encoding(s) for form data */
	if ((charset = (char *) xmlGetProp(n, (const xmlChar *) "accept-charset"))) {
		char *comma = strchr(charset, ',');
		if (!comma)
			/* only one => use it */
			comma = strdup(charset);
		else
			/* multiple => use first */
			comma = strndup(charset, comma - charset);

		xmlFree(charset);
		charset = comma;
	}
	else if (content->data.html.encoding)
		/* none specified => try document encoding */
		charset = strdup(content->data.html.encoding);
	else
		/* none specified and no document encoding => 8859-1 */
		charset = strdup("ISO-8859-1");

	if (!charset) {
		xmlFree(action);
		return false;
	}

	form = form_new(action, fmethod, charset);
	if (!form) {
		xmlFree(action);
		free(charset);
		return false;
	}
	form->prev = content->data.html.forms;
	content->data.html.forms = form;

	return true;
}


/**
 * Form control [17.4].
 */

bool box_input(BOX_SPECIAL_PARAMS)
{
	struct form_control *gadget = NULL;
	char *s, *type, *url;
	url_func_result res;

	type = (char *) xmlGetProp(n, (const xmlChar *) "type");

	if (type && strcasecmp(type, "password") == 0) {
		if (!box_input_text(n, content, box, 0, true))
			goto no_memory;
		gadget = box->gadget;
		gadget->box = box;

	} else if (type && strcasecmp(type, "file") == 0) {
		box->type = BOX_INLINE_BLOCK;
		box->gadget = gadget = form_new_control(GADGET_FILE);
		if (!gadget)
			goto no_memory;
		gadget->box = box;

	} else if (type && strcasecmp(type, "hidden") == 0) {
		/* no box for hidden inputs */
		gadget = form_new_control(GADGET_HIDDEN);
		if (!gadget)
			goto no_memory;

		if ((s = (char *) xmlGetProp(n, (const xmlChar *) "value"))) {
			gadget->value = strdup(s);
			xmlFree(s);
			if (!gadget->value)
				goto no_memory;
			gadget->length = strlen(gadget->value);
		}

	} else if (type && (strcasecmp(type, "checkbox") == 0 ||
			strcasecmp(type, "radio") == 0)) {
		box->gadget = gadget = form_new_control(type[0] == 'c' ||
				type[0] == 'C' ? GADGET_CHECKBOX :
				GADGET_RADIO);
		if (!gadget)
			goto no_memory;
		gadget->box = box;

		gadget->selected = xmlHasProp(n, (const xmlChar *) "checked");

		if ((s = (char *) xmlGetProp(n, (const xmlChar *) "value"))) {
			gadget->value = strdup(s);
			xmlFree(s);
			if (!gadget->value)
				goto no_memory;
			gadget->length = strlen(gadget->value);
		}

	} else if (type && (strcasecmp(type, "submit") == 0 ||
			strcasecmp(type, "reset") == 0)) {
		struct box *inline_container, *inline_box;
		if (!box_button(n, content, box, 0))
			goto no_memory;
		inline_container = box_create(0, 0, 0, 0, content);
		if (!inline_container)
			goto no_memory;
		inline_container->type = BOX_INLINE_CONTAINER;
		inline_box = box_create(box->style, 0, box->title, 0, content);
		if (!inline_box)
			goto no_memory;
		inline_box->type = BOX_INLINE;
		if (box->gadget->value != NULL)
			inline_box->text = talloc_strdup(content,
					box->gadget->value);
		else if (box->gadget->type == GADGET_SUBMIT)
			inline_box->text = talloc_strdup(content,
					messages_get("Form_Submit"));
		else
			inline_box->text = talloc_strdup(content,
					messages_get("Form_Reset"));
		if (!inline_box->text)
			goto no_memory;
		inline_box->length = strlen(inline_box->text);
		box_add_child(inline_container, inline_box);
		box_add_child(box, inline_container);

	} else if (type && strcasecmp(type, "button") == 0) {
		struct box *inline_container, *inline_box;
		if (!box_button(n, content, box, 0))
			goto no_memory;
		inline_container = box_create(0, 0, 0, 0, content);
		if (!inline_container)
			goto no_memory;
		inline_container->type = BOX_INLINE_CONTAINER;
		inline_box = box_create(box->style, 0, box->title, 0, content);
		if (!inline_box)
			goto no_memory;
		inline_box->type = BOX_INLINE;
		if ((s = (char *) xmlGetProp(n, (const xmlChar *) "value")))
			inline_box->text = talloc_strdup(content, s);
		else
			inline_box->text = talloc_strdup(content, "Button");
		if (!inline_box->text)
			goto no_memory;
		inline_box->length = strlen(inline_box->text);
		box_add_child(inline_container, inline_box);
		box_add_child(box, inline_container);

	} else if (type && strcasecmp(type, "image") == 0) {
		box->gadget = gadget = form_new_control(GADGET_IMAGE);
		if (!gadget)
			goto no_memory;
		gadget->box = box;
		gadget->type = GADGET_IMAGE;
		if ((s = (char *) xmlGetProp(n, (const xmlChar*) "src"))) {
			res = url_join(s, content->data.html.base_url, &url);
			xmlFree(s);
			/* if url is equivalent to the parent's url,
			 * we've got infinite inclusion. stop it here.
			 * also bail if url_join failed.
			 */
			if (res == URL_FUNC_OK &&
					strcasecmp(url, content->data.
					html.base_url) != 0) {
				if (!html_fetch_object(content, url,
						box, image_types,
						content->available_width,
						1000, false)) {
					free(url);
					goto no_memory;
			        }
	                }
	                free(url);
		}

	} else {
		/* the default type is "text" */
		if (!box_input_text(n, content, box, 0, false))
			goto no_memory;
		gadget = box->gadget;
		gadget->box = box;
	}

	if (type)
		xmlFree(type);

	if (gadget) {
		if (content->data.html.forms)
			form_add_control(content->data.html.forms, gadget);
		s = (char *) xmlGetProp(n, (const xmlChar *) "name");
		if (s) {
			gadget->name = strdup(s);
			xmlFree(s);
			if (!gadget->name)
				goto no_memory;
		}
	}

	*convert_children = false;
	return true;

no_memory:
	if (type)
		xmlFree(type);
	if (gadget)
		form_free_control(gadget);

	return false;
}


/**
 * Helper function for box_input().
 */

bool box_input_text(BOX_SPECIAL_PARAMS, bool password)
{
	char *s;
	struct box *inline_container, *inline_box;

	box->type = BOX_INLINE_BLOCK;
	box->gadget = form_new_control((password) ? GADGET_PASSWORD :
			GADGET_TEXTBOX);
	if (!box->gadget)
		return 0;
	box->gadget->box = box;

	box->gadget->maxlength = 100;
	if ((s = (char *) xmlGetProp(n, (const xmlChar *) "maxlength"))) {
		box->gadget->maxlength = atoi(s);
		xmlFree(s);
	}

	s = (char *) xmlGetProp(n, (const xmlChar *) "value");
	box->gadget->value = strdup((s != NULL) ? s : "");
	box->gadget->initial_value = strdup((box->gadget->value != NULL) ?
			box->gadget->value : "");
	if (s)
		xmlFree(s);
	if (box->gadget->value == NULL || box->gadget->initial_value == NULL) {
		box_free(box);
		return NULL;
	}
	box->gadget->length = strlen(box->gadget->value);

	inline_container = box_create(0, 0, 0, 0, content);
	if (!inline_container)
		return 0;
	inline_container->type = BOX_INLINE_CONTAINER;
	inline_box = box_create(box->style, 0, box->title, 0, content);
	if (!inline_box)
		return 0;
	inline_box->type = BOX_INLINE;
	if (password) {
		inline_box->length = strlen(box->gadget->value);
		inline_box->text = talloc_array(content, char,
				inline_box->length + 1);
		if (!inline_box->text)
			return 0;
		memset(inline_box->text, '*', inline_box->length);
		inline_box->text[inline_box->length] = '\0';
	} else {
		/* replace spaces/TABs with hard spaces to prevent line
		 * wrapping */
		char *text = cnv_space2nbsp(box->gadget->value);
		if (!text)
			return 0;
		inline_box->text = talloc_strdup(content, text);
		free(text);
		if (!inline_box->text)
			return 0;
		inline_box->length = strlen(inline_box->text);
	}
	box_add_child(inline_container, inline_box);
	box_add_child(box, inline_container);

	return box;
}


/**
 * Push button [17.5].
 */

bool box_button(BOX_SPECIAL_PARAMS)
{
	xmlChar *s;
	char *type = (char *) xmlGetProp(n, (const xmlChar *) "type");

	box->type = BOX_INLINE_BLOCK;

	if (!type || strcasecmp(type, "submit") == 0) {
		box->gadget = form_new_control(GADGET_SUBMIT);
	} else if (strcasecmp(type, "reset") == 0) {
		box->gadget = form_new_control(GADGET_RESET);
	} else {
		/* type="button" or unknown: just render the contents */
		xmlFree(type);
		return true;
	}

	if (type)
		xmlFree(type);

	if (!box->gadget)
		return false;

	if (content->data.html.forms)
		form_add_control(content->data.html.forms, box->gadget);
	box->gadget->box = box;
	if ((s = xmlGetProp(n, (const xmlChar *) "name")) != NULL) {
		box->gadget->name = strdup((char *) s);
		xmlFree(s);
		if (!box->gadget->name)
			return false;
	}
	if ((s = xmlGetProp(n, (const xmlChar *) "value")) != NULL) {
		box->gadget->value = strdup((char *) s);
		xmlFree(s);
		if (!box->gadget->value)
			return false;
	}

	return true;
}


/**
 * Option selector [17.6].
 */

bool box_select(BOX_SPECIAL_PARAMS)
{
	struct box *inline_container;
	struct box *inline_box;
	struct form_control *gadget;
	char* s;
	xmlNode *c, *c2;

	gadget = form_new_control(GADGET_SELECT);
	if (!gadget)
		return false;

	gadget->data.select.multiple = false;
	if ((s = (char *) xmlGetProp(n, (const xmlChar *) "multiple"))) {
		gadget->data.select.multiple = true;
		xmlFree(s);
	}

	gadget->data.select.items = NULL;
	gadget->data.select.last_item = NULL;
	gadget->data.select.num_items = 0;
	gadget->data.select.num_selected = 0;

	for (c = n->children; c; c = c->next) {
		if (strcmp((const char *) c->name, "option") == 0) {
			if (!box_select_add_option(gadget, c))
				goto no_memory;
		} else if (strcmp((const char *) c->name, "optgroup") == 0) {
			for (c2 = c->children; c2; c2 = c2->next) {
				if (strcmp((const char *) c2->name,
						"option") == 0) {
					if (!box_select_add_option(gadget, c2))
						goto no_memory;
				}
			}
		}
	}

	if (gadget->data.select.num_items == 0) {
		/* no options: ignore entire select */
		form_free_control(gadget);
		return true;
	}

	if ((s = (char *) xmlGetProp(n, (const xmlChar *) "name"))) {
		gadget->name = strdup(s);
		xmlFree(s);
		if (!gadget->name)
			goto no_memory;
	}

	box->type = BOX_INLINE_BLOCK;
	box->gadget = gadget;
	gadget->box = box;

	inline_container = box_create(0, 0, 0, 0, content);
	if (!inline_container)
		goto no_memory;
	inline_container->type = BOX_INLINE_CONTAINER;
	inline_box = box_create(box->style, 0, box->title, 0, content);
	if (!inline_box)
		goto no_memory;
	inline_box->type = BOX_INLINE;
	box_add_child(inline_container, inline_box);
	box_add_child(box, inline_container);

	if (!gadget->data.select.multiple &&
			gadget->data.select.num_selected == 0) {
		gadget->data.select.current = gadget->data.select.items;
		gadget->data.select.current->initial_selected =
			gadget->data.select.current->selected = true;
		gadget->data.select.num_selected = 1;
	}

	if (gadget->data.select.num_selected == 0)
		inline_box->text = talloc_strdup(content,
				messages_get("Form_None"));
	else if (gadget->data.select.num_selected == 1)
		inline_box->text = talloc_strdup(content,
				gadget->data.select.current->text);
	else
		inline_box->text = talloc_strdup(content,
				messages_get("Form_Many"));
	if (!inline_box->text)
		goto no_memory;

	inline_box->length = strlen(inline_box->text);

	if (content->data.html.forms)
		form_add_control(content->data.html.forms, box->gadget);

	*convert_children = false;
	return true;

no_memory:
	form_free_control(gadget);
	return false;
}


/**
 * Add an option to a form select control (helper function for box_select()).
 *
 * \param  control  select containing the option
 * \param  n        xml element node for <option>
 * \return  true on success, false on memory exhaustion
 */

bool box_select_add_option(struct form_control *control, xmlNode *n)
{
	char *value = 0;
	char *text = 0;
	bool selected;
	xmlChar *content;
	xmlChar *s;

	content = xmlNodeGetContent(n);
	if (!content)
		goto no_memory;
	text = squash_whitespace(content);
	xmlFree(content);
	if (!text)
		goto no_memory;

	if ((s = (char *) xmlGetProp(n, (const xmlChar *) "value"))) {
		value = strdup(s);
		xmlFree(s);
	} else
		value = strdup(text);
	if (!value)
		goto no_memory;

	selected = xmlHasProp(n, (const xmlChar *) "selected");

	if (!form_add_option(control, value, text, selected))
		goto no_memory;

	return true;

no_memory:
	free(value);
	free(text);
	return false;
}


/**
 * Multi-line text field [17.7].
 */

bool box_textarea(BOX_SPECIAL_PARAMS)
{
	/* A textarea is an INLINE_BLOCK containing a single INLINE_CONTAINER,
	 * which contains the text as runs of INLINE separated by BR. There is
	 * at least one INLINE. The first and last boxes are INLINE.
	 * Consecutive BR may not be present. These constraints are satisfied
	 * by using a 0-length INLINE for blank lines. */

	xmlChar *text, *current;
	struct box *inline_container, *inline_box, *br_box;
	char *s;
	size_t len;

	box->type = BOX_INLINE_BLOCK;
	box->gadget = form_new_control(GADGET_TEXTAREA);
	if (!box->gadget)
		return false;
	box->gadget->box = box;

	if ((s = (char *) xmlGetProp(n, (const xmlChar *) "name"))) {
		box->gadget->name = strdup(s);
		xmlFree(s);
		if (!box->gadget->name)
			return false;
	}

	inline_container = box_create(0, 0, box->title, 0, content);
	if (!inline_container)
		return false;
	inline_container->type = BOX_INLINE_CONTAINER;
	box_add_child(box, inline_container);

	current = text = xmlNodeGetContent(n);
	while (1) {
		/* BOX_INLINE */
		len = strcspn(current, "\r\n");
		s = talloc_strndup(content, current, len);
		if (!s) {
			xmlFree(content);
			return false;
		}

		inline_box = box_create(box->style, 0, box->title, 0, content);
		if (!inline_box)
			return false;
		inline_box->type = BOX_INLINE;
		inline_box->text = s;
		inline_box->length = len;
		box_add_child(inline_container, inline_box);

		current += len;
		if (current[0] == 0)
			/* finished */
			break;

		/* BOX_BR */
		br_box = box_create(box->style, 0, box->title, 0, content);
		if (!br_box)
			return false;
		br_box->type = BOX_BR;
		box_add_child(inline_container, br_box);

		if (current[0] == '\r' && current[1] == '\n')
			current += 2;
		else
			current++;
	}
	xmlFree(text);

	if (content->data.html.forms)
		form_add_control(content->data.html.forms, box->gadget);

	*convert_children = false;
	return true;
}


/**
 * Embedded object (not in any HTML specification:
 * see http://wp.netscape.com/assist/net_sites/new_html3_prop.html )
 */

bool box_embed(BOX_SPECIAL_PARAMS)
{
	struct object_params *params;
	struct object_param *param;
	xmlChar *src;
	xmlAttr *a;

	params = talloc(content, struct object_params);
	if (!params)
		return false;
	params->data = 0;
	params->type = 0;
	params->codetype = 0;
	params->codebase = 0;
	params->classid = 0;
	params->params = 0;

	/* src is a URL */
	if (!(src = xmlGetProp(n, (const xmlChar *) "src")))
		return true;
	if (!box_extract_link((char *) src, content->data.html.base_url,
			&params->data))
		return false;
	xmlFree(src);
	if (!params->data)
		return true;

	/* add attributes as parameters to linked list */
	for (a = n->properties; a; a = a->next) {
		if (strcasecmp((const char *) a->name, "src") == 0)
			continue;
		if (!a->children || !a->children->content)
			continue;

		param = talloc(content, struct object_param);
		if (!param)
			return false;
		param->name = talloc_strdup(content, (const char *) a->name);
		param->value = talloc_strdup(content,
				(char *) a->children->content);
		param->type = 0;
		param->valuetype = "data";
		param->next = 0;

		if (!param->name || !param->value)
			return false;

		param->next = params->params;
		params->params = param;
	}

	box->object_params = params;

	/* start fetch */
	return html_fetch_object(content, params->data, box, 0,
			content->available_width, 1000, false);
}

/**
 * \}
 */


/**
 * Get the value of an XML element's attribute.
 *
 * \param  n          xmlNode, of type XML_ELEMENT_NODE
 * \param  attribute  name of attribute
 * \param  context    talloc context for result buffer
 * \param  value      updated to value, if the attribute is present
 * \return  true on success, false if attribute present but memory exhausted
 *
 * Note that returning true does not imply that the attribute was found. If the
 * attribute was not found, *value will be unchanged.
 */

bool box_get_attribute(xmlNode *n, const char *attribute,
		void *context, char **value)
{
	xmlChar *s = xmlGetProp(n, (const xmlChar *) attribute);
	if (!s)
		return true;
	*value = talloc_strdup(context, s);
	xmlFree(s);
	if (!*value)
		return false;
	return true;
}


/**
 * Extract a URL from a relative link, handling junk like whitespace and
 * attempting to read a real URL from "javascript:" links.
 *
 * \param  rel     relative URL taken from page
 * \param  base    base for relative URLs
 * \param  result  updated to target URL on heap, unchanged if extract failed
 * \return  true on success, false on memory exhaustion
 */

bool box_extract_link(const char *rel, const char *base, char **result)
{
	char *s, *s1, *apos0 = 0, *apos1 = 0, *quot0 = 0, *quot1 = 0;
	unsigned int i, j, end;
	url_func_result res;

	s1 = s = malloc(3 * strlen(rel) + 1);
	if (!s)
		return false;

	/* copy to s, removing white space and control characters */
	for (i = 0; rel[i] && isspace(rel[i]); i++)
		;
	for (end = strlen(rel); end != i && isspace(rel[end - 1]); end--)
		;
	for (j = 0; i != end; i++) {
		if ((unsigned char) rel[i] < 0x20) {
			; /* skip control characters */
		} else if (rel[i] == ' ') {
			s[j++] = '%';
			s[j++] = '2';
			s[j++] = '0';
		} else {
			s[j++] = rel[i];
		}
	}
	s[j] = 0;

	/* extract first quoted string out of "javascript:" link */
	if (strncmp(s, "javascript:", 11) == 0) {
		apos0 = strchr(s, '\'');
		if (apos0)
			apos1 = strchr(apos0 + 1, '\'');
		quot0 = strchr(s, '"');
		if (quot0)
			quot1 = strchr(quot0 + 1, '"');
		if (apos0 && apos1 && (!quot0 || !quot1 || apos0 < quot0)) {
			*apos1 = 0;
			s1 = apos0 + 1;
		} else if (quot0 && quot1) {
			*quot1 = 0;
			s1 = quot0 + 1;
		}
	}

	/* construct absolute URL */
	res = url_join(s1, base, result);
	free(s);
	if (res == URL_FUNC_NOMEM)
		return false;
	else if (res == URL_FUNC_FAILED)
		return true;

	return true;
}


/**
 * Parse a multi-length-list, as defined by HTML 4.01.
 *
 * \param  s        string to parse
 * \param  count    updated to number of entries
 * \param  context  talloc context block
 * \return  array of struct box_multi_length, or 0 on memory exhaustion
 */

struct box_multi_length *box_parse_multi_lengths(const char *s,
		unsigned int *count, void *context)
{
	char *end;
	unsigned int i, n;
	struct box_multi_length *length;

	for (i = 0, n = 1; s[i]; i++)
		if (s[i] == ',')
			n++;

	length = talloc_array(context, struct box_multi_length, n);
	if (!length)
		return NULL;

	for (i = 0; i != n; i++) {
		while (isspace(*s))
			s++;
		length[i].value = strtof(s, &end);
		if (length[i].value <= 0)
			length[i].value = 1;
		s = end;
		switch (*s) {
			case '%': length[i].type = LENGTH_PERCENT; break;
			case '*': length[i].type = LENGTH_RELATIVE; break;
			default:  length[i].type = LENGTH_PX; break;
		}
		while (*s && *s != ',')
			s++;
		if (*s == ',')
			s++;
	}

	*count = n;
	return length;
}