cairo/src/cairo-tag-stack.c

/* -*- Mode: c; c-basic-offset: 4; indent-tabs-mode: t; tab-width: 8; -*- */
/* cairo - a vector graphics library with display and print output
 *
 * Copyright © 2016 Adrian Johnson
 *
 * This library is free software; you can redistribute it and/or
 * modify it either under the terms of the GNU Lesser General Public
 * License version 2.1 as published by the Free Software Foundation
 * (the "LGPL") or, at your option, under the terms of the Mozilla
 * Public License Version 1.1 (the "MPL"). If you do not alter this
 * notice, a recipient may use your version of this file under either
 * the MPL or the LGPL.
 *
 * You should have received a copy of the LGPL along with this library
 * in the file COPYING-LGPL-2.1; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
 * You should have received a copy of the MPL along with this library
 * in the file COPYING-MPL-1.1
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
 * OF ANY KIND, either express or implied. See the LGPL or the MPL for
 * the specific language governing rights and limitations.
 *
 * The Original Code is the cairo graphics library.
 *
 * The Initial Developer of the Original Code is Adrian Johnson.
 *
 * Contributor(s):
 *	Adrian Johnson <ajohnson@redneon.com>
 */

#include "cairoint.h"

#include "cairo-tag-stack-private.h"

/* Tagged PDF must have one of these tags at the top level */
static const char * _cairo_tag_stack_tagged_pdf_top_level_element_list[] =
{
    "Document",
    "Part",
    "Art",
    "Sect",
    "Div",
    NULL
};

/* List of valid tag names. Table numbers reference PDF 32000 */
static const char * _cairo_tag_stack_struct_pdf_list[] =
{
    /* Table 333 - Grouping Elements */
    "Document",
    "Part",
    "Art",
    "Sect",
    "Div",
    "BlockQuote",
    "Caption",
    "TOC",
    "TOCI",
    "Index",
    "NonStruct",
    "Private",

    /* Table 335 - Standard structure types for paragraphlike elements */
    "P", "H",
    "H1", "H2", "H3", "H4", "H5", "H6",

    /* Table 336 - Standard structure types for list elements */
    "L", "LI", "Lbl", "LBody",

    /* Table 337 - Standard structure types for table elements */
    "Table",
    "TR", "TH", "TD",
    "THead", "TBody", "TFoot",

    /* Table 338 - Standard structure types for inline-level structure elements */
    "Span",
    "Quote",
    "Note",
    "Reference",
    "BibEntry",
    "Code",
    "Link", /* CAIRO_TAG_LINK */
    "Annot",
    "Ruby",
    "Warichu",

    /* Table 339 - Standard structure types for Ruby and Warichu elements */
    "RB", "RT", "RP",
    "WT", "WP",

    /* Table 340 - Standard structure types for illustration elements */
    "Figure",
    "Formula",
    "Form",

    /* Section 14.8.2.2.2 - Artifacts */
    "Artifact",

    NULL
};

/* List of cairo specific tag names */
static const char * _cairo_tag_stack_cairo_tag_list[] =
{
    CAIRO_TAG_DEST,
    CAIRO_TAG_CONTENT,
    CAIRO_TAG_CONTENT_REF,
    NULL
};

void
_cairo_tag_stack_init (cairo_tag_stack_t *stack)
{
    cairo_list_init (&stack->list);
    stack->type = TAG_TREE_TYPE_NO_TAGS;
    stack->size = 0;
}

void
_cairo_tag_stack_fini (cairo_tag_stack_t *stack)
{
    while (! cairo_list_is_empty (&stack->list)) {
	cairo_tag_stack_elem_t *elem;

	elem = cairo_list_first_entry (&stack->list, cairo_tag_stack_elem_t, link);
	cairo_list_del (&elem->link);
	free (elem->name);
	free (elem->attributes);
	free (elem);
    }
}

cairo_tag_stack_structure_type_t
_cairo_tag_stack_get_structure_type (cairo_tag_stack_t *stack)
{
    return stack->type;
}

static cairo_bool_t
name_in_list (const char *name, const char **list)
{
    if (! name)
	return FALSE;

    while (*list) {
	if (strcmp (name, *list) == 0)
	    return TRUE;
	list++;
    }

    return FALSE;
}

cairo_int_status_t
_cairo_tag_stack_push (cairo_tag_stack_t *stack,
		       const char        *name,
		       const char        *attributes)
{
    cairo_tag_stack_elem_t *elem;

    if (! name_in_list (name, _cairo_tag_stack_struct_pdf_list) &&
	! name_in_list (name, _cairo_tag_stack_cairo_tag_list))
    {
	stack->type = TAG_TYPE_INVALID;
	return _cairo_tag_error ("Invalid tag: %s", name);
    }

    cairo_tag_stack_elem_t *top = _cairo_tag_stack_top_elem (stack);
    if (top &&
	(strcmp (top->name, CAIRO_TAG_CONTENT) == 0 ||
	 strcmp (top->name, CAIRO_TAG_CONTENT_REF) == 0 ||
	 strcmp (top->name, "Artifact") == 0))
    {
	return _cairo_tag_error ("%s tag can not contain nested tags",
				 (strcmp (top->name, CAIRO_TAG_CONTENT) == 0) ? "CAIRO_TAG_CONTENT" :
				 ((strcmp (top->name, CAIRO_TAG_CONTENT_REF) == 0) ? "CAIRO_TAG_CONTENT_REF" : top->name));
    }

    if (stack->type == TAG_TREE_TYPE_NO_TAGS) {
	if (name_in_list (name, _cairo_tag_stack_tagged_pdf_top_level_element_list))
	    stack->type = TAG_TREE_TYPE_TAGGED;
	else if (strcmp (name, "Link") == 0)
	    stack->type = TAG_TREE_TYPE_LINK_ONLY;
	else if (name_in_list (name, _cairo_tag_stack_struct_pdf_list))
	    stack->type = TAG_TREE_TYPE_STRUCTURE;
    } else {
	if (stack->type == TAG_TREE_TYPE_LINK_ONLY &&
	    (strcmp (name, "Link") != 0) &&
	    name_in_list (name, _cairo_tag_stack_struct_pdf_list))
	{
	    stack->type = TAG_TREE_TYPE_STRUCTURE;
	}
    }

    elem = _cairo_malloc (sizeof(cairo_tag_stack_elem_t));
    if (unlikely (elem == NULL))
	return _cairo_error (CAIRO_STATUS_NO_MEMORY);

    elem->name = strdup (name);
    if (unlikely (elem->name == NULL))
	return _cairo_error (CAIRO_STATUS_NO_MEMORY);

    if (attributes) {
	elem->attributes = strdup (attributes);
	if (unlikely (elem->attributes == NULL))
	    return _cairo_error (CAIRO_STATUS_NO_MEMORY);
    } else {
	elem->attributes = NULL;
    }

    elem->data = NULL;

    cairo_list_add_tail (&elem->link, &stack->list);
    stack->size++;

    return CAIRO_STATUS_SUCCESS;
}

cairo_private void
_cairo_tag_stack_set_top_data (cairo_tag_stack_t *stack,
			       void        *data)
{
    cairo_tag_stack_elem_t *top;

    top = _cairo_tag_stack_top_elem (stack);
    if (top)
	top->data = data;
}

cairo_int_status_t
_cairo_tag_stack_pop (cairo_tag_stack_t *stack,
		      const char *name,
		      cairo_tag_stack_elem_t **elem)
{
    cairo_tag_stack_elem_t *top;

    top = _cairo_tag_stack_top_elem (stack);
    if (!top) {
	stack->type = TAG_TYPE_INVALID;
	return _cairo_tag_error ("cairo_tag_end(\"%s\") no matching begin tag", name);
    }

    cairo_list_del (&top->link);
    stack->size--;
    if (strcmp (top->name, name) != 0) {
	cairo_status_t status =
	    _cairo_tag_error ("cairo_tag_end(\"%s\") does not matching previous begin tag \"%s\"",
			      name, top->name);
	stack->type = TAG_TYPE_INVALID;
	_cairo_tag_stack_free_elem (top);
	return status;
    }

    if (elem)
	*elem = top;
    else
	_cairo_tag_stack_free_elem (top);

    return CAIRO_STATUS_SUCCESS;
}

cairo_tag_stack_elem_t *
_cairo_tag_stack_top_elem (cairo_tag_stack_t *stack)
{
    if (cairo_list_is_empty (&stack->list))
	return NULL;

    return cairo_list_last_entry (&stack->list, cairo_tag_stack_elem_t, link);
}

void
_cairo_tag_stack_foreach (cairo_tag_stack_t *stack,
			  void (*func)(cairo_tag_stack_elem_t *elem,
				       void *closure),
			  void *closure)
{
    cairo_tag_stack_elem_t *elem;

    cairo_list_foreach_entry (elem, cairo_tag_stack_elem_t, &stack->list, link) {
	func (elem, closure);
    }
}

void
_cairo_tag_stack_free_elem (cairo_tag_stack_elem_t *elem)
{
    free (elem->name);
    free (elem->attributes);
    free (elem);
}

cairo_tag_type_t
_cairo_tag_get_type (const char *name)
{
    if (! name_in_list (name, _cairo_tag_stack_struct_pdf_list) &&
	! name_in_list (name, _cairo_tag_stack_cairo_tag_list))
	return TAG_TYPE_INVALID;

    if (strcmp(name, "Link") == 0)
	return (TAG_TYPE_LINK | TAG_TYPE_STRUCTURE);

    if (strcmp(name, CAIRO_TAG_DEST) == 0)
	return TAG_TYPE_DEST;

    if (strcmp(name, CAIRO_TAG_CONTENT) == 0)
	return TAG_TYPE_CONTENT;

    if (strcmp(name, CAIRO_TAG_CONTENT_REF) == 0)
	return TAG_TYPE_CONTENT_REF;

    return TAG_TYPE_STRUCTURE;
}

cairo_status_t
_cairo_tag_error (const char *fmt, ...)
{
    va_list ap;

    if (getenv ("CAIRO_DEBUG_TAG") != NULL) {
	printf ("TAG ERROR: ");
	va_start (ap, fmt);
	vprintf (fmt, ap);
	va_end (ap);
	printf ("\n");
    }
    return _cairo_error (CAIRO_STATUS_TAG_ERROR);
}

void
_cairo_tag_warning (const char *fmt, ...)
{
    va_list ap;

    if (getenv ("CAIRO_DEBUG_TAG") != NULL) {
	printf ("TAG WARNING: ");
	va_start (ap, fmt);
	vprintf (fmt, ap);
	va_end (ap);
	printf ("\n");
    }
}