rsvg-base.c

/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* vim: set sw=4 sts=4 ts=4 expandtab: */
/*
   rsvg.c: SAX-based renderer for SVG files into a GdkPixbuf.

   Copyright (C) 2000 Eazel, Inc.
   Copyright (C) 2002 Dom Lachowicz <cinamod@hotmail.com>

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   This program 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with this program; if not, write to the
   Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.

   Author: Raph Levien <raph@artofcode.com>
*/

#include "config.h"
#define _GNU_SOURCE 1

#include "rsvg.h"
#include "rsvg-compat.h"
#include "rsvg-private.h"
#include "rsvg-css.h"
#include "rsvg-styles.h"
#include "rsvg-shapes.h"
#include "rsvg-structure.h"
#include "rsvg-image.h"
#include "rsvg-io.h"
#include "rsvg-text.h"
#include "rsvg-filter.h"
#include "rsvg-mask.h"
#include "rsvg-marker.h"
#include "rsvg-cairo-render.h"

#include <libxml/uri.h>
#include <libxml/parser.h>
#include <libxml/parserInternals.h>

#include <gio/gio.h>

#include <math.h>
#include <string.h>
#include <stdarg.h>
#include <limits.h>
#include <stdlib.h>

#include "rsvg-path.h"
#include "rsvg-paint-server.h"
#include "rsvg-xml.h"

#ifdef G_OS_WIN32
static char *
rsvg_realpath_utf8 (const char *filename, const char *unused)
{
    wchar_t *wfilename;
    wchar_t *wfull;
    char *full;

    wfilename = g_utf8_to_utf16 (filename, -1, NULL, NULL, NULL);
    if (!wfilename)
        return NULL;

    wfull = _wfullpath (NULL, wfilename, 0);
    g_free (wfilename);
    if (!wfull)
        return NULL;

    full = g_utf16_to_utf8 (wfull, -1, NULL, NULL, NULL);
    free (wfull);

    if (!full)
        return NULL;

    return full;
}

#define realpath(a,b) rsvg_realpath_utf8 (a, b)
#endif

/*
 * This is configurable at runtime
 */
#define RSVG_DEFAULT_DPI_X 90.0
#define RSVG_DEFAULT_DPI_Y 90.0

G_GNUC_INTERNAL
double rsvg_internal_dpi_x = RSVG_DEFAULT_DPI_X;
G_GNUC_INTERNAL
double rsvg_internal_dpi_y = RSVG_DEFAULT_DPI_Y;

static xmlSAXHandler rsvgSAXHandlerStruct;
static gboolean rsvgSAXHandlerStructInited = FALSE;

typedef struct _RsvgSaxHandlerDefs {
    RsvgSaxHandler super;
    RsvgHandle *ctx;
} RsvgSaxHandlerDefs;

typedef struct _RsvgSaxHandlerStyle {
    RsvgSaxHandler super;
    RsvgSaxHandlerDefs *parent;
    RsvgHandle *ctx;
    GString *style;
    gboolean is_text_css;
} RsvgSaxHandlerStyle;

typedef struct {
    RsvgSaxHandler super;
    RsvgHandle *ctx;
    const char *name;
    GString *string;
    GString **stringptr;
} RsvgSaxHandlerExtra;

/* hide this fact from the general public */
typedef RsvgSaxHandlerExtra RsvgSaxHandlerTitle;
typedef RsvgSaxHandlerExtra RsvgSaxHandlerDesc;
typedef RsvgSaxHandlerExtra RsvgSaxHandlerMetadata;

static void
rsvg_style_handler_free (RsvgSaxHandler * self)
{
    RsvgSaxHandlerStyle *z = (RsvgSaxHandlerStyle *) self;
    RsvgHandle *ctx = z->ctx;

    if (z->is_text_css)
        rsvg_parse_cssbuffer (ctx, z->style->str, z->style->len);

    g_string_free (z->style, TRUE);
    g_free (z);
}

static void
rsvg_style_handler_characters (RsvgSaxHandler * self, const char *ch, int len)
{
    RsvgSaxHandlerStyle *z = (RsvgSaxHandlerStyle *) self;
    g_string_append_len (z->style, ch, len);
}

static void
rsvg_style_handler_start (RsvgSaxHandler * self, const char *name, RsvgPropertyBag * atts)
{
}

static void
rsvg_style_handler_end (RsvgSaxHandler * self, const char *name)
{
    RsvgSaxHandlerStyle *z = (RsvgSaxHandlerStyle *) self;
    RsvgHandle *ctx = z->ctx;
    RsvgSaxHandler *prev = &z->parent->super;

    if (!strcmp (name, "style")) {
        if (ctx->priv->handler != NULL) {
            ctx->priv->handler->free (ctx->priv->handler);
            ctx->priv->handler = prev;
        }
    }
}

static void
rsvg_start_style (RsvgHandle * ctx, RsvgPropertyBag *atts)
{
    RsvgSaxHandlerStyle *handler = g_new0 (RsvgSaxHandlerStyle, 1);
    const char *type;

    type = rsvg_property_bag_lookup (atts, "type");

    handler->super.free = rsvg_style_handler_free;
    handler->super.characters = rsvg_style_handler_characters;
    handler->super.start_element = rsvg_style_handler_start;
    handler->super.end_element = rsvg_style_handler_end;
    handler->ctx = ctx;

    handler->style = g_string_new (NULL);

    /* FIXME: See these:
     *
     * https://www.w3.org/TR/SVG/styling.html#StyleElementTypeAttribute
     * https://www.w3.org/TR/SVG/styling.html#ContentStyleTypeAttribute
     *
     * If the "type" attribute is not present, we should fallback to the
     * "contentStyleType" attribute of the svg element, which in turn
     * defaults to "text/css".
     *
     * See where is_text_css is used to see where we parse the contents
     * of the style element.
     */
    handler->is_text_css = (type == NULL) || (g_ascii_strcasecmp (type, "text/css") == 0);

    handler->parent = (RsvgSaxHandlerDefs *) ctx->priv->handler;
    ctx->priv->handler = &handler->super;
}


static void
rsvg_standard_element_start (RsvgHandle * ctx, const char *name, RsvgPropertyBag * atts)
{
    /*replace this stuff with a hash for fast reading! */
    RsvgNode *newnode = NULL;
    if (!strcmp (name, "g"))
        newnode = rsvg_new_group ();
    else if (!strcmp (name, "a"))       /*treat anchors as groups for now */
        newnode = rsvg_new_group ();
    else if (!strcmp (name, "switch"))
        newnode = rsvg_new_switch ();
    else if (!strcmp (name, "defs"))
        newnode = rsvg_new_defs ();
    else if (!strcmp (name, "use"))
        newnode = rsvg_new_use ();
    else if (!strcmp (name, "path"))
        newnode = rsvg_new_path ();
    else if (!strcmp (name, "line"))
        newnode = rsvg_new_line ();
    else if (!strcmp (name, "rect"))
        newnode = rsvg_new_rect ();
    else if (!strcmp (name, "ellipse"))
        newnode = rsvg_new_ellipse ();
    else if (!strcmp (name, "circle"))
        newnode = rsvg_new_circle ();
    else if (!strcmp (name, "polygon"))
        newnode = rsvg_new_polygon ();
    else if (!strcmp (name, "polyline"))
        newnode = rsvg_new_polyline ();
    else if (!strcmp (name, "symbol"))
        newnode = rsvg_new_symbol ();
    else if (!strcmp (name, "svg"))
        newnode = rsvg_new_svg ();
    else if (!strcmp (name, "mask"))
        newnode = rsvg_new_mask ();
    else if (!strcmp (name, "clipPath"))
        newnode = rsvg_new_clip_path ();
    else if (!strcmp (name, "image"))
        newnode = rsvg_new_image ();
    else if (!strcmp (name, "marker"))
        newnode = rsvg_new_marker ();
    else if (!strcmp (name, "stop"))
        newnode = rsvg_new_stop ();
    else if (!strcmp (name, "pattern"))
        newnode = rsvg_new_pattern ();
    else if (!strcmp (name, "linearGradient"))
        newnode = rsvg_new_linear_gradient ();
    else if (!strcmp (name, "radialGradient"))
        newnode = rsvg_new_radial_gradient ();
    else if (!strcmp (name, "conicalGradient"))
        newnode = rsvg_new_radial_gradient ();
    else if (!strcmp (name, "filter"))
        newnode = rsvg_new_filter ();
    else if (!strcmp (name, "feBlend"))
        newnode = rsvg_new_filter_primitive_blend ();
    else if (!strcmp (name, "feColorMatrix"))
        newnode = rsvg_new_filter_primitive_color_matrix ();
    else if (!strcmp (name, "feComponentTransfer"))
        newnode = rsvg_new_filter_primitive_component_transfer ();
    else if (!strcmp (name, "feComposite"))
        newnode = rsvg_new_filter_primitive_composite ();
    else if (!strcmp (name, "feConvolveMatrix"))
        newnode = rsvg_new_filter_primitive_convolve_matrix ();
    else if (!strcmp (name, "feDiffuseLighting"))
        newnode = rsvg_new_filter_primitive_diffuse_lighting ();
    else if (!strcmp (name, "feDisplacementMap"))
        newnode = rsvg_new_filter_primitive_displacement_map ();
    else if (!strcmp (name, "feFlood"))
        newnode = rsvg_new_filter_primitive_flood ();
    else if (!strcmp (name, "feGaussianBlur"))
        newnode = rsvg_new_filter_primitive_gaussian_blur ();
    else if (!strcmp (name, "feImage"))
        newnode = rsvg_new_filter_primitive_image ();
    else if (!strcmp (name, "feMerge"))
        newnode = rsvg_new_filter_primitive_merge ();
    else if (!strcmp (name, "feMorphology"))
        newnode = rsvg_new_filter_primitive_erode ();
    else if (!strcmp (name, "feOffset"))
        newnode = rsvg_new_filter_primitive_offset ();
    else if (!strcmp (name, "feSpecularLighting"))
        newnode = rsvg_new_filter_primitive_specular_lighting ();
    else if (!strcmp (name, "feTile"))
        newnode = rsvg_new_filter_primitive_tile ();
    else if (!strcmp (name, "feTurbulence"))
        newnode = rsvg_new_filter_primitive_turbulence ();
    else if (!strcmp (name, "feMergeNode"))
        newnode = rsvg_new_filter_primitive_merge_node ();
    else if (!strcmp (name, "feFuncR"))
        newnode = rsvg_new_node_component_transfer_function ('r'); /* See rsvg_filter_primitive_component_transfer_render() for where these values are used */
    else if (!strcmp (name, "feFuncG"))
        newnode = rsvg_new_node_component_transfer_function ('g');
    else if (!strcmp (name, "feFuncB"))
        newnode = rsvg_new_node_component_transfer_function ('b');
    else if (!strcmp (name, "feFuncA"))
        newnode = rsvg_new_node_component_transfer_function ('a');
    else if (!strcmp (name, "feDistantLight"))
        newnode = rsvg_new_node_light_source ('d');
    else if (!strcmp (name, "feSpotLight"))
        newnode = rsvg_new_node_light_source ('s');
    else if (!strcmp (name, "fePointLight"))
        newnode = rsvg_new_node_light_source ('p');
    /* hack to make multiImage sort-of work */
    else if (!strcmp (name, "multiImage"))
        newnode = rsvg_new_switch ();
    else if (!strcmp (name, "subImageRef"))
        newnode = rsvg_new_image ();
    else if (!strcmp (name, "subImage"))
        newnode = rsvg_new_group ();
    else if (!strcmp (name, "text"))
        newnode = rsvg_new_text ();
    else if (!strcmp (name, "tspan"))
        newnode = rsvg_new_tspan ();
    else if (!strcmp (name, "tref"))
        newnode = rsvg_new_tref ();
    else {
        /* Whenever we encounter a node we don't understand, represent it as a defs.
         * This is like a group, but it doesn't do any rendering of children.  The
         * effect is that we will ignore all children of unknown elements.
         */
		newnode = rsvg_new_defs ();
	}

    if (newnode) {
        g_assert (RSVG_NODE_TYPE (newnode) != RSVG_NODE_TYPE_INVALID);
        newnode->name = (char *) name; /* libxml will keep this while parsing */
        newnode->parent = ctx->priv->currentnode;
        rsvg_node_set_atts (newnode, ctx, atts);
        rsvg_defs_register_memory (ctx->priv->defs, newnode);
        if (ctx->priv->currentnode) {
            rsvg_node_group_pack (ctx->priv->currentnode, newnode);
            ctx->priv->currentnode = newnode;
        } else if (RSVG_NODE_TYPE (newnode) == RSVG_NODE_TYPE_SVG) {
            ctx->priv->treebase = newnode;
            ctx->priv->currentnode = newnode;
        }
    }
}

/* extra (title, desc, metadata) */

static void
rsvg_extra_handler_free (RsvgSaxHandler * self)
{
    RsvgSaxHandlerExtra *z = (RsvgSaxHandlerExtra *) self;

    if (z->stringptr) {
        if (*z->stringptr)
            g_string_free (*z->stringptr, TRUE);
        *z->stringptr = z->string;
    } else if (z->string) {
        g_string_free (z->string, TRUE);
    }

    g_free (self);
}

static void
rsvg_extra_handler_characters (RsvgSaxHandler * self, const char *ch, int len)
{
    RsvgSaxHandlerExtra *z = (RsvgSaxHandlerExtra *) self;

    /* This isn't quite the correct behavior - in theory, any graphics
       element may contain a title, desc, or metadata element */

    if (!z->string)
        return;

    if (!ch || !len)
        return;

    if (!g_utf8_validate ((char *) ch, len, NULL)) {
        char *utf8;
        utf8 = rsvg_make_valid_utf8 ((char *) ch, len);
        g_string_append (z->string, utf8);
        g_free (utf8);
    } else {
        g_string_append_len (z->string, (char *) ch, len);
    }
}

static void
rsvg_extra_handler_start (RsvgSaxHandler * self, const char *name, RsvgPropertyBag * atts)
{
}

static void
rsvg_extra_handler_end (RsvgSaxHandler * self, const char *name)
{
    RsvgSaxHandlerExtra *z = (RsvgSaxHandlerExtra *) self;
    RsvgHandle *ctx = z->ctx;

    if (!strcmp (name, z->name)) {
        if (ctx->priv->handler != NULL) {
            ctx->priv->handler->free (ctx->priv->handler);
            ctx->priv->handler = NULL;
        }
    }
}

static RsvgSaxHandlerExtra *
rsvg_start_extra (RsvgHandle * ctx,
                  const char *name,
                  GString **stringptr)
{
    RsvgSaxHandlerExtra *handler = g_new0 (RsvgSaxHandlerExtra, 1);
    RsvgNode *treebase = ctx->priv->treebase;
    RsvgNode *currentnode = ctx->priv->currentnode;
    gboolean do_care;

    /* only parse <extra> for the <svg> node.
     * This isn't quite the correct behavior - any graphics
     * element may contain a <extra> element.
     */
    do_care = treebase != NULL && treebase == currentnode;

    handler->super.free = rsvg_extra_handler_free;
    handler->super.characters = rsvg_extra_handler_characters;
    handler->super.start_element = rsvg_extra_handler_start;
    handler->super.end_element = rsvg_extra_handler_end;
    handler->ctx = ctx;
    handler->name = name; /* interned */
    handler->string = do_care ? g_string_new (NULL) : NULL;
    handler->stringptr = do_care ? stringptr : NULL;

    ctx->priv->handler = &handler->super;

    return handler;
}

/* start desc */

static void
rsvg_start_desc (RsvgHandle * ctx)
{
    rsvg_start_extra (ctx, "desc", &ctx->priv->desc);
}

/* end desc */

/* start title */

static void
rsvg_start_title (RsvgHandle * ctx)
{
    rsvg_start_extra (ctx, "title", &ctx->priv->title);
}

/* end title */

/* start metadata */

static void
rsvg_metadata_props_enumerate (const char *key, const char *value, gpointer user_data)
{
    GString *metadata = (GString *) user_data;
    g_string_append_printf (metadata, "%s=\"%s\" ", key, value);
}

static void
rsvg_metadata_handler_start (RsvgSaxHandler * self, const char *name, RsvgPropertyBag * atts)
{
    RsvgSaxHandlerMetadata *z = (RsvgSaxHandlerMetadata *) self;

    rsvg_extra_handler_start (self, name, atts);

    if (!z->string)
        return;

    g_string_append_printf (z->string, "<%s ", name);
    rsvg_property_bag_enumerate (atts, rsvg_metadata_props_enumerate, z->string);
    g_string_append (z->string, ">\n");
}

static void
rsvg_metadata_handler_end (RsvgSaxHandler * self, const char *name)
{
    RsvgSaxHandlerMetadata *z = (RsvgSaxHandlerMetadata *) self;

    if (strcmp (name, z->name) != 0) {
        if (z->string)
            g_string_append_printf (z->string, "</%s>\n", name);
    } else {
        rsvg_extra_handler_end (self, name);
    }
}

static void
rsvg_start_metadata (RsvgHandle * ctx)
{
    RsvgSaxHandlerMetadata *handler = rsvg_start_extra (ctx, "metadata", &ctx->priv->metadata);

    handler->super.start_element = rsvg_metadata_handler_start;
    handler->super.end_element = rsvg_metadata_handler_end;
}

/* end metadata */

/* start xinclude */

typedef struct _RsvgSaxHandlerXinclude {
    RsvgSaxHandler super;

    RsvgSaxHandler *prev_handler;
    RsvgHandle *ctx;
    gboolean success;
    gboolean in_fallback;
} RsvgSaxHandlerXinclude;

static void
 rsvg_start_xinclude (RsvgHandle * ctx, RsvgPropertyBag * atts);
static void
 rsvg_characters_impl (RsvgHandle * ctx, const xmlChar * ch, int len);

static void
rsvg_xinclude_handler_free (RsvgSaxHandler * self)
{
    g_free (self);
}

static void
rsvg_xinclude_handler_characters (RsvgSaxHandler * self, const char *ch, int len)
{
    RsvgSaxHandlerXinclude *z = (RsvgSaxHandlerXinclude *) self;

    if (z->in_fallback) {
        rsvg_characters_impl (z->ctx, (const xmlChar *) ch, len);
    }
}

static void
rsvg_xinclude_handler_start (RsvgSaxHandler * self, const char *name, RsvgPropertyBag * atts)
{
    RsvgSaxHandlerXinclude *z = (RsvgSaxHandlerXinclude *) self;

    if (!z->success) {
        if (z->in_fallback) {
            if (!strcmp (name, "xi:include"))
                rsvg_start_xinclude (z->ctx, atts);
            else
                rsvg_standard_element_start (z->ctx, (const char *) name, atts);
        } else if (!strcmp (name, "xi:fallback")) {
            z->in_fallback = TRUE;
        }
    }
}

static void
rsvg_xinclude_handler_end (RsvgSaxHandler * self, const char *name)
{
    RsvgSaxHandlerXinclude *z = (RsvgSaxHandlerXinclude *) self;
    RsvgHandle *ctx = z->ctx;

    if (!strcmp (name, "include") || !strcmp (name, "xi:include")) {
        if (ctx->priv->handler != NULL) {
            RsvgSaxHandler *previous_handler;

            previous_handler = z->prev_handler;
            ctx->priv->handler->free (ctx->priv->handler);
            ctx->priv->handler = previous_handler;
        }
    } else if (z->in_fallback) {
        if (!strcmp (name, "xi:fallback"))
            z->in_fallback = FALSE;
    }
}

static void
rsvg_set_xml_parse_options(xmlParserCtxtPtr xml_parser,
                           RsvgHandle *ctx)
{
    int options;

    options = (XML_PARSE_NONET |
               XML_PARSE_BIG_LINES);

    if (ctx->priv->flags & RSVG_HANDLE_FLAG_UNLIMITED) {
        options |= XML_PARSE_HUGE;
    }

    xmlCtxtUseOptions (xml_parser, options);

    /* if false, external entities work, but internal ones don't. if true, internal entities
       work, but external ones don't. favor internal entities, in order to not cause a
       regression */
    xml_parser->replaceEntities = TRUE;
}

static xmlParserCtxtPtr
create_xml_push_parser (RsvgHandle *handle,
                        const char *base_uri)
{
    xmlParserCtxtPtr parser;

    parser = xmlCreatePushParserCtxt (&rsvgSAXHandlerStruct, handle, NULL, 0, base_uri);
    rsvg_set_xml_parse_options (parser, handle);

    return parser;
}

static xmlParserCtxtPtr
create_xml_stream_parser (RsvgHandle    *handle,
                          GInputStream  *stream,
                          GCancellable  *cancellable,
                          GError       **error)
{
    xmlParserCtxtPtr parser;

    parser = rsvg_create_xml_parser_from_stream (&rsvgSAXHandlerStruct,
                                                 handle,
                                                 stream,
                                                 cancellable,
                                                 error);
    if (parser) {
        rsvg_set_xml_parse_options (parser, handle);
    }

    return parser;
}

/* http://www.w3.org/TR/xinclude/ */
static void
rsvg_start_xinclude (RsvgHandle * ctx, RsvgPropertyBag * atts)
{
    RsvgSaxHandlerXinclude *handler;
    const char *href, *parse;
    gboolean success = FALSE;

    href = rsvg_property_bag_lookup (atts, "href");
    if (href == NULL)
        goto fallback;

    parse = rsvg_property_bag_lookup (atts, "parse");
    if (parse && !strcmp (parse, "text")) {
        char *data;
        gsize data_len;
        const char *encoding;

        data = _rsvg_handle_acquire_data (ctx, href, NULL, &data_len, NULL);
        if (data == NULL)
            goto fallback;

        encoding = rsvg_property_bag_lookup (atts, "encoding");
        if (encoding && g_ascii_strcasecmp (encoding, "UTF-8") != 0) {
            char *text_data;
            gsize text_data_len;

            text_data = g_convert (data, data_len, "utf-8", encoding, NULL,
                                   &text_data_len, NULL);
            g_free (data);

            data = text_data;
            data_len = text_data_len;
        }

        rsvg_characters_impl (ctx, (xmlChar *) data, data_len);

        g_free (data);
    } else {
        /* xml */
        GInputStream *stream;
        GError *err = NULL;
        xmlParserCtxtPtr xml_parser;

        stream = _rsvg_handle_acquire_stream (ctx, href, NULL, NULL);
        if (stream == NULL)
            goto fallback;

        xml_parser = create_xml_stream_parser (ctx,
                                               stream,
                                               NULL, /* cancellable */
                                               &err);

        g_object_unref (stream);

        if (xml_parser) {
            (void) xmlParseDocument (xml_parser);

            xml_parser = rsvg_free_xml_parser_and_doc (xml_parser);
        }

        g_clear_error (&err);
    }

    success = TRUE;

  fallback:

    /* needed to handle xi:fallback */
    handler = g_new0 (RsvgSaxHandlerXinclude, 1);

    handler->super.free = rsvg_xinclude_handler_free;
    handler->super.characters = rsvg_xinclude_handler_characters;
    handler->super.start_element = rsvg_xinclude_handler_start;
    handler->super.end_element = rsvg_xinclude_handler_end;
    handler->prev_handler = ctx->priv->handler;
    handler->ctx = ctx;
    handler->success = success;

    ctx->priv->handler = &handler->super;
}

/* end xinclude */

static gboolean
loading_limits_exceeded (RsvgHandle *handle)
{
    /* This is a mitigation for SVG files which create millions of elements
     * in an attempt to exhaust memory.  We don't allow loading more than
     * this number of elements during the initial streaming load process.
     */
    return handle->priv->num_loaded_elements > 200000;
}

static void
rsvg_start_element (void *data, const xmlChar * name, const xmlChar ** atts)
{
    RsvgPropertyBag *bag;
    RsvgHandle *ctx = (RsvgHandle *) data;

    /* In a different way from librsvg 2.42, we do the following check here, not
     * in rsvg_standard_element_start() as it is done there.  This is because
     * librsvg 2.40 still creates nodes for <title> and <metadata> elements, and
     * we'd like to prevent unbounded memory consuption for those elements, too.
     */
    if (loading_limits_exceeded (ctx)) {
        g_set_error (ctx->priv->error, RSVG_ERROR, 0, "instancing limit");

        xmlStopParser (ctx->priv->ctxt);
        return;
    }

    ctx->priv->num_loaded_elements += 1;

    bag = rsvg_property_bag_new ((const char **) atts);

    if (ctx->priv->handler) {
        ctx->priv->handler_nest++;
        if (ctx->priv->handler->start_element != NULL)
            ctx->priv->handler->start_element (ctx->priv->handler, (const char *) name, bag);
    } else {
        const char *tempname;
        for (tempname = (const char *) name; *tempname != '\0'; tempname++)
            if (*tempname == ':')
                name = (const xmlChar *) (tempname + 1);

        if (!strcmp ((const char *) name, "style"))
            rsvg_start_style (ctx, bag);
        else if (!strcmp ((const char *) name, "title"))
            rsvg_start_title (ctx);
        else if (!strcmp ((const char *) name, "desc"))
            rsvg_start_desc (ctx);
        else if (!strcmp ((const char *) name, "metadata"))
            rsvg_start_metadata (ctx);
        else if (!strcmp ((const char *) name, "include"))      /* xi:include */
            rsvg_start_xinclude (ctx, bag);
        else
            rsvg_standard_element_start (ctx, (const char *) name, bag);
    }

    rsvg_property_bag_free (bag);
}

static void
rsvg_end_element (void *data, const xmlChar * name)
{
    RsvgHandle *ctx = (RsvgHandle *) data;

    if (ctx->priv->handler_nest > 0 && ctx->priv->handler != NULL) {
        if (ctx->priv->handler->end_element != NULL)
            ctx->priv->handler->end_element (ctx->priv->handler, (const char *) name);
        ctx->priv->handler_nest--;
    } else {
        const char *tempname;
        for (tempname = (const char *) name; *tempname != '\0'; tempname++)
            if (*tempname == ':')
                name = (const xmlChar *) (tempname + 1);

        if (ctx->priv->handler != NULL) {
            ctx->priv->handler->free (ctx->priv->handler);
            ctx->priv->handler = NULL;
        }

        if (ctx->priv->currentnode &&
            !strcmp ((const char *) name, ctx->priv->currentnode->name))
                rsvg_pop_def_group (ctx);

        /* FIXMEchpe: shouldn't this check that currentnode == treebase or sth like that? */
        if (ctx->priv->treebase && !strcmp ((const char *)name, "svg"))
            _rsvg_node_svg_apply_atts ((RsvgNodeSvg *)ctx->priv->treebase, ctx);
    }
}

static void
_rsvg_node_chars_free (RsvgNode * node)
{
    RsvgNodeChars *self = (RsvgNodeChars *) node;
    g_string_free (self->contents, TRUE);
    _rsvg_node_free (node);
}

static RsvgNodeChars *
rsvg_new_node_chars (const char *text,
                     int len)
{
    RsvgNodeChars *self;

    self = g_new (RsvgNodeChars, 1);
    _rsvg_node_init (&self->super, RSVG_NODE_TYPE_CHARS);

    if (!g_utf8_validate (text, len, NULL)) {
        char *utf8;
        utf8 = rsvg_make_valid_utf8 (text, len);
        self->contents = g_string_new (utf8);
        g_free (utf8);
    } else {
        self->contents = g_string_new_len (text, len);
    }

    self->super.free = _rsvg_node_chars_free;
    self->super.state->cond_true = FALSE;

    return self;
}

static void
rsvg_characters_impl (RsvgHandle * ctx, const xmlChar * ch, int len)
{
    RsvgNodeChars *self;

    if (!ch || !len)
        return;

    if (ctx->priv->currentnode) {
        RsvgNodeType type = RSVG_NODE_TYPE (ctx->priv->currentnode);
        if (type == RSVG_NODE_TYPE_TSPAN ||
            type == RSVG_NODE_TYPE_TEXT) {
            guint i;

            /* find the last CHARS node in the text or tspan node, so that we
               can coalesce the text, and thus avoid screwing up the Pango layouts */
            self = NULL;
            for (i = 0; i < ctx->priv->currentnode->children->len; i++) {
                RsvgNode *node = g_ptr_array_index (ctx->priv->currentnode->children, i);
                if (RSVG_NODE_TYPE (node) == RSVG_NODE_TYPE_CHARS) {
                    self = (RsvgNodeChars*)node;
                }
                else if (RSVG_NODE_TYPE (node) == RSVG_NODE_TYPE_TSPAN) {
                    self = NULL;
                }
            }

            if (self != NULL) {
                if (!g_utf8_validate ((char *) ch, len, NULL)) {
                    char *utf8;
                    utf8 = rsvg_make_valid_utf8 ((char *) ch, len);
                    g_string_append (self->contents, utf8);
                    g_free (utf8);
                } else {
                    g_string_append_len (self->contents, (char *)ch, len);
                }

                return;
            }
        }
    }

    self = rsvg_new_node_chars ((char *) ch, len);

    rsvg_defs_register_memory (ctx->priv->defs, (RsvgNode *) self);
    if (ctx->priv->currentnode)
        rsvg_node_group_pack (ctx->priv->currentnode, (RsvgNode *) self);
}

static void
rsvg_characters (void *data, const xmlChar * ch, int len)
{
    RsvgHandle *ctx = (RsvgHandle *) data;

    if (ctx->priv->handler && ctx->priv->handler->characters != NULL) {
        ctx->priv->handler->characters (ctx->priv->handler, (const char *) ch, len);
        return;
    }

    rsvg_characters_impl (ctx, ch, len);
}

static xmlEntityPtr
rsvg_get_entity (void *data, const xmlChar * name)
{
    RsvgHandle *ctx = (RsvgHandle *) data;
    xmlEntityPtr entity;

    entity = g_hash_table_lookup (ctx->priv->entities, name);

    return entity;
}

static void
rsvg_entity_decl (void *data, const xmlChar * name, int type,
                  const xmlChar * publicId, const xmlChar * systemId, xmlChar * content)
{
    RsvgHandle *ctx = (RsvgHandle *) data;
    GHashTable *entities = ctx->priv->entities;
    xmlEntityPtr entity;
    xmlChar *resolvedSystemId = NULL, *resolvedPublicId = NULL;

    if (systemId)
        resolvedSystemId = xmlBuildRelativeURI (systemId, (xmlChar*) rsvg_handle_get_base_uri (ctx));
    else if (publicId)
        resolvedPublicId = xmlBuildRelativeURI (publicId, (xmlChar*) rsvg_handle_get_base_uri (ctx));

    if (type == XML_EXTERNAL_PARAMETER_ENTITY && !content) {
        char *entity_data;
        gsize entity_data_len;

        if (systemId)
            entity_data = _rsvg_handle_acquire_data (ctx,
                                                     (const char *) systemId,
                                                     NULL,
                                                     &entity_data_len,
                                                     NULL);
        else if (publicId)
            entity_data = _rsvg_handle_acquire_data (ctx,
                                                     (const char *) publicId,
                                                     NULL,
                                                     &entity_data_len,
                                                     NULL);
        else
            entity_data = NULL;

        if (entity_data) {
            content = xmlCharStrndup (entity_data, entity_data_len);
            g_free (entity_data);
        }
    }

    entity = xmlNewEntity(NULL, name, type, resolvedPublicId, resolvedSystemId, content);

    xmlFree(resolvedPublicId);
    xmlFree(resolvedSystemId);

    g_hash_table_insert (entities, g_strdup ((const char*) name), entity);
}

static void
rsvg_unparsed_entity_decl (void *ctx,
                           const xmlChar * name,
                           const xmlChar * publicId,
                           const xmlChar * systemId, const xmlChar * notationName)
{
    rsvg_entity_decl (ctx, name, XML_INTERNAL_GENERAL_ENTITY, publicId, systemId, NULL);
}

static xmlEntityPtr
rsvg_get_parameter_entity (void *data, const xmlChar * name)
{
    RsvgHandle *ctx = (RsvgHandle *) data;
    xmlEntityPtr entity;

    entity = g_hash_table_lookup (ctx->priv->entities, name);

    return entity;
}

static void
rsvg_error_cb (void *data, const char *msg, ...)
{
#ifdef G_ENABLE_DEBUG
    va_list args;

    va_start (args, msg);
    vfprintf (stderr, msg, args);
    va_end (args);
#endif
}

static void
rsvg_processing_instruction (void *ctx, const xmlChar * target, const xmlChar * data)
{
    /* http://www.w3.org/TR/xml-stylesheet/ */
    RsvgHandle *handle = (RsvgHandle *) ctx;

    if (!strcmp ((const char *) target, "xml-stylesheet")) {
        RsvgPropertyBag *atts;
        char **xml_atts;

        xml_atts = rsvg_css_parse_xml_attribute_string ((const char *) data);

        if (xml_atts) {
            const char *value;

            atts = rsvg_property_bag_new ((const char **) xml_atts);
            value = rsvg_property_bag_lookup (atts, "alternate");
            if (!value || !value[0] || (strcmp (value, "no") != 0)) {
                value = rsvg_property_bag_lookup (atts, "type");
                if (value && strcmp (value, "text/css") == 0) {
                    value = rsvg_property_bag_lookup (atts, "href");
                    if (value && value[0]) {
                        char *style_data;
                        gsize style_data_len;
                        char *mime_type = NULL;

                        style_data = _rsvg_handle_acquire_data (handle,
                                                                value,
                                                                &mime_type,
                                                                &style_data_len,
                                                                NULL);
                        if (style_data && 
                            mime_type &&
                            strcmp (mime_type, "text/css") == 0) {
                            rsvg_parse_cssbuffer (handle, style_data, style_data_len);
                        }

                        g_free (mime_type);
                        g_free (style_data);
                    }
                }
            }

            rsvg_property_bag_free (atts);
            g_strfreev (xml_atts);
        }
    }
}

void
rsvg_SAX_handler_struct_init (void)
{
    if (!rsvgSAXHandlerStructInited) {
        rsvgSAXHandlerStructInited = TRUE;

        memset (&rsvgSAXHandlerStruct, 0, sizeof (rsvgSAXHandlerStruct));

        rsvgSAXHandlerStruct.getEntity = rsvg_get_entity;
        rsvgSAXHandlerStruct.entityDecl = rsvg_entity_decl;
        rsvgSAXHandlerStruct.unparsedEntityDecl = rsvg_unparsed_entity_decl;
        rsvgSAXHandlerStruct.getParameterEntity = rsvg_get_parameter_entity;
        rsvgSAXHandlerStruct.characters = rsvg_characters;
        rsvgSAXHandlerStruct.error = rsvg_error_cb;
        rsvgSAXHandlerStruct.cdataBlock = rsvg_characters;
        rsvgSAXHandlerStruct.startElement = rsvg_start_element;
        rsvgSAXHandlerStruct.endElement = rsvg_end_element;
        rsvgSAXHandlerStruct.processingInstruction = rsvg_processing_instruction;
    }
}

/* http://www.ietf.org/rfc/rfc2396.txt */

static gboolean
rsvg_path_is_uri (char const *path)
{
    char const *p;

    if (path == NULL)
        return FALSE;

    if (strlen (path) < 4)
        return FALSE;

    if ((path[0] < 'a' || path[0] > 'z') &&
        (path[0] < 'A' || path[0] > 'Z')) {
        return FALSE;
    }

    for (p = &path[1];
	    (*p >= 'a' && *p <= 'z') ||
        (*p >= 'A' && *p <= 'Z') ||
        (*p >= '0' && *p <= '9') ||
         *p == '+' ||
         *p == '-' ||
         *p == '.';
        p++);

    if (strlen (p) < 3)
        return FALSE;

    return (p[0] == ':' && p[1] == '/' && p[2] == '/');
}

static gchar *
rsvg_get_base_uri_from_filename (const gchar * filename)
{
    gchar *current_dir;
    gchar *absolute_filename;
    gchar *base_uri;

    if (g_path_is_absolute (filename))
        return g_filename_to_uri (filename, NULL, NULL);

    current_dir = g_get_current_dir ();
    absolute_filename = g_build_filename (current_dir, filename, NULL);
    base_uri = g_filename_to_uri (absolute_filename, NULL, NULL);
    g_free (absolute_filename);
    g_free (current_dir);

    return base_uri;
}

/**
 * rsvg_handle_set_base_uri:
 * @handle: A #RsvgHandle
 * @base_uri: The base uri
 *
 * Set the base URI for this SVG. This can only be called before rsvg_handle_write()
 * has been called.
 *
 * Since: 2.9
 */
void
rsvg_handle_set_base_uri (RsvgHandle * handle, const char *base_uri)
{
    gchar *uri;
    GFile *file;

    g_return_if_fail (handle != NULL);

    if (base_uri == NULL)
	return;

    if (rsvg_path_is_uri (base_uri)) 
        uri = g_strdup (base_uri);
    else
        uri = rsvg_get_base_uri_from_filename (base_uri);

    file = g_file_new_for_uri (uri ? uri : "data:");
    rsvg_handle_set_base_gfile (handle, file);
    g_object_unref (file);
    g_free (uri);
}

/**
 * rsvg_handle_set_base_gfile:
 * @handle: a #RsvgHandle
 * @base_file: a #GFile
 *
 * Set the base URI for @handle from @file.
 * Note: This function may only be called before rsvg_handle_write()
 * or rsvg_handle_read_stream_sync() has been called.
 *
 * Since: 2.32
 */
void
rsvg_handle_set_base_gfile (RsvgHandle *handle,
                            GFile      *base_file)
{
    RsvgHandlePrivate *priv;

    g_return_if_fail (RSVG_IS_HANDLE (handle));
    g_return_if_fail (G_IS_FILE (base_file));

    priv = handle->priv;

    g_object_ref (base_file);
    if (priv->base_gfile)
        g_object_unref (priv->base_gfile);
    priv->base_gfile = base_file;

    g_free (priv->base_uri);
    priv->base_uri = g_file_get_uri (base_file);
}

/**
 * rsvg_handle_get_base_uri:
 * @handle: A #RsvgHandle
 *
 * Gets the base uri for this #RsvgHandle.
 *
 * Returns: the base uri, possibly null
 * Since: 2.8
 */
const char *
rsvg_handle_get_base_uri (RsvgHandle * handle)
{
    g_return_val_if_fail (handle, NULL);
    return handle->priv->base_uri;
}

/**
 * rsvg_error_quark:
 *
 * The error domain for RSVG
 *
 * Returns: The error domain
 */
GQuark
rsvg_error_quark (void)
{
    /* don't use from_static_string(), since librsvg might be used in a module
       that's ultimately unloaded */
    return g_quark_from_string ("rsvg-error-quark");
}

static void
rsvg_set_error (GError **error, xmlParserCtxtPtr ctxt)
{
    xmlErrorPtr xerr;

    xerr = xmlCtxtGetLastError (ctxt);
    if (xerr) {
        g_set_error (error, rsvg_error_quark (), 0,
                     _("Error domain %d code %d on line %d column %d of %s: %s"),
                     xerr->domain, xerr->code,
                     xerr->line, xerr->int2,
                     xerr->file ? xerr->file : "data",
                     xerr->message ? xerr->message: "-");
    } else {
        g_set_error (error, rsvg_error_quark (), 0, _("Error parsing XML data"));
    }
}

static gboolean
rsvg_handle_write_impl (RsvgHandle * handle, const guchar * buf, gsize count, GError ** error)
{
    GError *real_error = NULL;
    int result;

    rsvg_return_val_if_fail (handle != NULL, FALSE, error);

    handle->priv->error = &real_error;

    if (handle->priv->ctxt == NULL) {
        handle->priv->ctxt = create_xml_push_parser (handle, rsvg_handle_get_base_uri (handle));
    }

    result = xmlParseChunk (handle->priv->ctxt, (char *) buf, count, 0);
    if (result != 0) {
        rsvg_set_error (error, handle->priv->ctxt);
        return FALSE;
    }

    handle->priv->error = NULL;

    if (real_error != NULL) {
        g_propagate_error (error, real_error);
        return FALSE;
    }

    return TRUE;
}

static gboolean
rsvg_handle_close_impl (RsvgHandle * handle, GError ** error)
{
    GError *real_error = NULL;

    handle->priv->error = &real_error;

    if (handle->priv->ctxt != NULL) {
        int result;

        result = xmlParseChunk (handle->priv->ctxt, "", 0, TRUE);
        if (result != 0) {
            rsvg_set_error (error, handle->priv->ctxt);
            handle->priv->ctxt = rsvg_free_xml_parser_and_doc (handle->priv->ctxt);
            return FALSE;
        }

        handle->priv->ctxt = rsvg_free_xml_parser_and_doc (handle->priv->ctxt);
    }

    handle->priv->error = NULL;

    if (real_error != NULL) {
        g_propagate_error (error, real_error);
        return FALSE;
    }

    return TRUE;
}

void
rsvg_drawing_ctx_free (RsvgDrawingCtx * handle)
{
    rsvg_render_free (handle->render);

    rsvg_state_free_all (handle->state);

	/* the drawsub stack's nodes are owned by the ->defs */
	g_slist_free (handle->drawsub_stack);

    g_warn_if_fail (handle->acquired_nodes == NULL);
    g_slist_free (handle->acquired_nodes);
	
    if (handle->pango_context != NULL)
        g_object_unref (handle->pango_context);

    g_free (handle);
}

/**
 * rsvg_handle_get_metadata:
 * @handle: An #RsvgHandle
 *
 * Returns the SVG's metadata in UTF-8 or %NULL. You must make a copy
 * of this metadata if you wish to use it after @handle has been freed.
 *
 * Returns: (nullable): The SVG's title
 *
 * Since: 2.9
 *
 * Deprecated: 2.36
 */
const char *
rsvg_handle_get_metadata (RsvgHandle * handle)
{
    g_return_val_if_fail (handle, NULL);

    if (handle->priv->metadata)
        return handle->priv->metadata->str;
    else
        return NULL;
}

/**
 * rsvg_handle_get_title:
 * @handle: An #RsvgHandle
 *
 * Returns the SVG's title in UTF-8 or %NULL. You must make a copy
 * of this title if you wish to use it after @handle has been freed.
 *
 * Returns: (nullable): The SVG's title
 *
 * Since: 2.4
 *
 * Deprecated: 2.36
 */
const char *
rsvg_handle_get_title (RsvgHandle * handle)
{
    g_return_val_if_fail (handle, NULL);

    if (handle->priv->title)
        return handle->priv->title->str;
    else
        return NULL;
}

/**
 * rsvg_handle_get_desc:
 * @handle: An #RsvgHandle
 *
 * Returns the SVG's description in UTF-8 or %NULL. You must make a copy
 * of this description if you wish to use it after @handle has been freed.
 *
 * Returns: (nullable): The SVG's description
 *
 * Since: 2.4
 *
 * Deprecated: 2.36
 */
const char *
rsvg_handle_get_desc (RsvgHandle * handle)
{
    g_return_val_if_fail (handle, NULL);

    if (handle->priv->desc)
        return handle->priv->desc->str;
    else
        return NULL;
}

/**
 * rsvg_handle_get_dimensions:
 * @handle: A #RsvgHandle
 * @dimension_data: (out): A place to store the SVG's size
 *
 * Get the SVG's size. Do not call from within the size_func callback, because an infinite loop will occur.
 *
 * Since: 2.14
 */
void
rsvg_handle_get_dimensions (RsvgHandle * handle, RsvgDimensionData * dimension_data)
{
    /* This function is probably called from the cairo_render functions.
     * To prevent an infinite loop we are saving the state.
     */
    if (!handle->priv->in_loop) {
        handle->priv->in_loop = TRUE;
        rsvg_handle_get_dimensions_sub (handle, dimension_data, NULL);
        handle->priv->in_loop = FALSE;
    } else {
        /* Called within the size function, so return a standard size */
        dimension_data->em = dimension_data->width = 1;
        dimension_data->ex = dimension_data->height = 1;
    }
}

/**
 * rsvg_handle_get_dimensions_sub:
 * @handle: A #RsvgHandle
 * @dimension_data: (out): A place to store the SVG's size
 * @id: (nullable): An element's id within the SVG, or %NULL to get
 *   the dimension of the whole SVG.  For example, if you have a layer
 *   called "layer1" for that you want to get the dimension, pass
 *   "#layer1" as the id.
 *
 * Get the size of a subelement of the SVG file. Do not call from within the size_func callback, because an infinite loop will occur.
 *
 * Since: 2.22
 */
gboolean
rsvg_handle_get_dimensions_sub (RsvgHandle * handle, RsvgDimensionData * dimension_data, const char *id)
{
    cairo_t *cr;
    cairo_surface_t *target;
    RsvgDrawingCtx *draw;
    RsvgNodeSvg *root = NULL;
    RsvgNode *sself = NULL;
    RsvgBbox bbox;
    gboolean retval = FALSE;

    gboolean handle_subelement = TRUE;

    g_return_val_if_fail (handle, FALSE);
    g_return_val_if_fail (dimension_data, FALSE);

    memset (dimension_data, 0, sizeof (RsvgDimensionData));

    if (id && *id) {
        sself = rsvg_defs_lookup (handle->priv->defs, id);

        if (sself == handle->priv->treebase)
            id = NULL;
    }
    else
        sself = handle->priv->treebase;

    if (!sself && id)
        return FALSE;

    root = (RsvgNodeSvg *) handle->priv->treebase;

    if (!root)
        return FALSE;

    bbox.rect.x = bbox.rect.y = 0;
    bbox.rect.width = bbox.rect.height = 1;

    if (!id && (root->w.factor == 'p' || root->h.factor == 'p')
            && !root->vbox.active)
        handle_subelement = TRUE;
    else if (!id && root->w.length != -1 && root->h.length != -1)
        handle_subelement = FALSE;

    if (handle_subelement == TRUE) {
        target = cairo_image_surface_create (CAIRO_FORMAT_RGB24,
                                             1, 1);
        cr = cairo_create  (target);

        draw = rsvg_cairo_new_drawing_ctx (cr, handle);

        if (!draw) {
            cairo_destroy (cr);
            cairo_surface_destroy (target);

            return FALSE;
        }

        while (sself != NULL) {
            draw->drawsub_stack = g_slist_prepend (draw->drawsub_stack, sself);
            sself = sself->parent;
        }

        rsvg_state_push (draw);
        cairo_save (cr);

        rsvg_node_draw (handle->priv->treebase, draw, 0);
        bbox = RSVG_CAIRO_RENDER (draw->render)->bbox;

        if (rsvg_drawing_ctx_limits_exceeded (draw)) {
            retval = FALSE;
        } else {
            retval = TRUE;
        }

        cairo_restore (cr);
        rsvg_state_pop (draw);
        rsvg_drawing_ctx_free (draw);
        cairo_destroy (cr);
        cairo_surface_destroy (target);

        dimension_data->width = bbox.rect.width;
        dimension_data->height = bbox.rect.height;
    } else {
        bbox.rect.width = root->vbox.rect.width;
        bbox.rect.height = root->vbox.rect.height;

        dimension_data->width = (int) (_rsvg_css_hand_normalize_length (&root->w, handle->priv->dpi_x,
                                       bbox.rect.width + bbox.rect.x * 2, 12) + 0.5);
        dimension_data->height = (int) (_rsvg_css_hand_normalize_length (&root->h, handle->priv->dpi_y,
                                         bbox.rect.height + bbox.rect.y * 2,
                                         12) + 0.5);

        retval = TRUE;
    }
    
    dimension_data->em = dimension_data->width;
    dimension_data->ex = dimension_data->height;

    if (handle->priv->size_func)
        (*handle->priv->size_func) (&dimension_data->width, &dimension_data->height,
                                    handle->priv->user_data);

    return retval;
}

/**
 * rsvg_handle_get_position_sub:
 * @handle: A #RsvgHandle
 * @position_data: (out): A place to store the SVG fragment's position.
 * @id: An element's id within the SVG.
 * For example, if you have a layer called "layer1" for that you want to get
 * the position, pass "##layer1" as the id.
 *
 * Get the position of a subelement of the SVG file. Do not call from within
 * the size_func callback, because an infinite loop will occur.
 *
 * Since: 2.22
 */
gboolean
rsvg_handle_get_position_sub (RsvgHandle * handle, RsvgPositionData * position_data, const char *id)
{
    RsvgDrawingCtx		*draw;
    RsvgNodeSvg			*root;
    RsvgNode			*node;
    RsvgBbox			 bbox;
    RsvgDimensionData    dimension_data;
    cairo_surface_t		*target = NULL;
    cairo_t				*cr = NULL;
    gboolean			 retval = FALSE;

    g_return_val_if_fail (handle, FALSE);
    g_return_val_if_fail (position_data, FALSE);

    /* Short-cut when no id is given. */
    if (NULL == id || '\0' == *id) {
        position_data->x = 0;
        position_data->y = 0;
        return TRUE;
    }

    memset (position_data, 0, sizeof (*position_data));
    memset (&dimension_data, 0, sizeof (dimension_data));

    node = rsvg_defs_lookup (handle->priv->defs, id);
    if (!node) {
        return FALSE;
    } else if (node == handle->priv->treebase) {
        /* Root node. */
        position_data->x = 0;
        position_data->y = 0;
        return TRUE;
    }

    root = (RsvgNodeSvg *) handle->priv->treebase;
    if (!root)
        return FALSE;

    target = cairo_image_surface_create (CAIRO_FORMAT_RGB24, 1, 1);
    cr = cairo_create  (target);
    draw = rsvg_cairo_new_drawing_ctx (cr, handle);
    if (!draw)
        goto bail;

    while (node != NULL) {
        draw->drawsub_stack = g_slist_prepend (draw->drawsub_stack, node);
        node = node->parent;
    }

    rsvg_state_push (draw);
    cairo_save (cr);

    rsvg_node_draw (handle->priv->treebase, draw, 0);
    bbox = RSVG_CAIRO_RENDER (draw->render)->bbox;

    if (rsvg_drawing_ctx_limits_exceeded (draw)) {
        retval = FALSE;
    } else {
        retval = TRUE;
    }

    cairo_restore (cr);
    rsvg_state_pop (draw);
    rsvg_drawing_ctx_free (draw);

    position_data->x = bbox.rect.x;
    position_data->y = bbox.rect.y;
    dimension_data.width = bbox.rect.width;
    dimension_data.height = bbox.rect.height;

    dimension_data.em = dimension_data.width;
    dimension_data.ex = dimension_data.height;

    if (handle->priv->size_func)
        (*handle->priv->size_func) (&dimension_data.width, &dimension_data.height,
                                    handle->priv->user_data);

bail:
    if (cr)
        cairo_destroy (cr);
    if (target)
        cairo_surface_destroy (target);

    return retval;
}

/** 
 * rsvg_handle_has_sub:
 * @handle: a #RsvgHandle
 * @id: an element's id within the SVG
 *
 * Checks whether the element @id exists in the SVG document.
 *
 * Returns: %TRUE if @id exists in the SVG document
 *
 * Since: 2.22
 */
gboolean
rsvg_handle_has_sub (RsvgHandle * handle,
                     const char *id)
{
    g_return_val_if_fail (handle, FALSE);

    if (G_UNLIKELY (!id || !id[0]))
      return FALSE;

    return rsvg_defs_lookup (handle->priv->defs, id) != NULL;
}

/** 
 * rsvg_set_default_dpi:
 * @dpi: Dots Per Inch (aka Pixels Per Inch)
 *
 * Sets the DPI for the all future outgoing pixbufs. Common values are
 * 75, 90, and 300 DPI. Passing a number <= 0 to @dpi will
 * reset the DPI to whatever the default value happens to be.
 *
 * Since: 2.8
 */
void
rsvg_set_default_dpi (double dpi)
{
    rsvg_set_default_dpi_x_y (dpi, dpi);
}

/** 
 * rsvg_set_default_dpi_x_y:
 * @dpi_x: Dots Per Inch (aka Pixels Per Inch)
 * @dpi_y: Dots Per Inch (aka Pixels Per Inch)
 *
 * Sets the DPI for the all future outgoing pixbufs. Common values are
 * 75, 90, and 300 DPI. Passing a number <= 0 to @dpi will
 * reset the DPI to whatever the default value happens to be.
 *
 * Since: 2.8
 */
void
rsvg_set_default_dpi_x_y (double dpi_x, double dpi_y)
{
    if (dpi_x <= 0.)
        rsvg_internal_dpi_x = RSVG_DEFAULT_DPI_X;
    else
        rsvg_internal_dpi_x = dpi_x;

    if (dpi_y <= 0.)
        rsvg_internal_dpi_y = RSVG_DEFAULT_DPI_Y;
    else
        rsvg_internal_dpi_y = dpi_y;
}

/**
 * rsvg_handle_set_dpi:
 * @handle: An #RsvgHandle
 * @dpi: Dots Per Inch (aka Pixels Per Inch)
 *
 * Sets the DPI for the outgoing pixbuf. Common values are
 * 75, 90, and 300 DPI. Passing a number <= 0 to @dpi will
 * reset the DPI to whatever the default value happens to be.
 *
 * Since: 2.8
 */
void
rsvg_handle_set_dpi (RsvgHandle * handle, double dpi)
{
    rsvg_handle_set_dpi_x_y (handle, dpi, dpi);
}

/**
 * rsvg_handle_set_dpi_x_y:
 * @handle: An #RsvgHandle
 * @dpi_x: Dots Per Inch (aka Pixels Per Inch)
 * @dpi_y: Dots Per Inch (aka Pixels Per Inch)
 *
 * Sets the DPI for the outgoing pixbuf. Common values are
 * 75, 90, and 300 DPI. Passing a number <= 0 to #dpi_x or @dpi_y will
 * reset the DPI to whatever the default value happens to be.
 *
 * Since: 2.8
 */
void
rsvg_handle_set_dpi_x_y (RsvgHandle * handle, double dpi_x, double dpi_y)
{
    g_return_if_fail (handle != NULL);

    if (dpi_x <= 0.)
        handle->priv->dpi_x = rsvg_internal_dpi_x;
    else
        handle->priv->dpi_x = dpi_x;

    if (dpi_y <= 0.)
        handle->priv->dpi_y = rsvg_internal_dpi_y;
    else
        handle->priv->dpi_y = dpi_y;
}

/**
 * rsvg_handle_set_size_callback:
 * @handle: An #RsvgHandle
 * @size_func: (nullable): A sizing function, or %NULL
 * @user_data: User data to pass to @size_func, or %NULL
 * @user_data_destroy: Destroy function for @user_data, or %NULL
 *
 * Sets the sizing function for the @handle.  This function is called right
 * after the size of the image has been loaded.  The size of the image is passed
 * in to the function, which may then modify these values to set the real size
 * of the generated pixbuf.  If the image has no associated size, then the size
 * arguments are set to -1.
 *
 * Deprecated: Set up a cairo matrix and use rsvg_handle_render_cairo() instead.
 * You can call rsvg_handle_get_dimensions() to figure out the size of your SVG,
 * and then scale it to the desired size via Cairo.  For example, the following
 * code renders an SVG at a specified size, scaled proportionally from whatever
 * original size it may have had:
 *
 * |[<!-- language="C" -->
 * void
 * render_scaled_proportionally (RsvgHandle *handle, cairo_t cr, int width, int height)
 * {
 *     RsvgDimensionData dimensions;
 *     double x_factor, y_factor;
 *     double scale_factor;
 * 
 *     rsvg_handle_get_dimensions (handle, &dimensions);
 * 
 *     x_factor = (double) width / dimensions.width;
 *     y_factor = (double) height / dimensions.height;
 * 
 *     scale_factor = MIN (x_factor, y_factor);
 * 
 *     cairo_scale (cr, scale_factor, scale_factor);
 * 
 *     rsvg_handle_render_cairo (handle, cr);
 * }
 * ]|
 **/
void
rsvg_handle_set_size_callback (RsvgHandle * handle,
                               RsvgSizeFunc size_func,
                               gpointer user_data, GDestroyNotify user_data_destroy)
{
    g_return_if_fail (handle != NULL);

    if (handle->priv->user_data_destroy)
        (*handle->priv->user_data_destroy) (handle->priv->user_data);

    handle->priv->size_func = size_func;
    handle->priv->user_data = user_data;
    handle->priv->user_data_destroy = user_data_destroy;
}

#define GZ_MAGIC_0 ((guchar) 0x1f)
#define GZ_MAGIC_1 ((guchar) 0x8b)

/* Creates handle->priv->compressed_input_stream and adds the gzip header data
 * to it.  We implicitly consume the header data from the caller in
 * rsvg_handle_write(); that's why we add it back here.
 */
static void
create_compressed_input_stream (RsvgHandle *handle)
{
    RsvgHandlePrivate *priv = handle->priv;

    static const guchar gz_magic[2] = { GZ_MAGIC_0, GZ_MAGIC_1 };

    g_assert (priv->compressed_input_stream == NULL);

    priv->compressed_input_stream = g_memory_input_stream_new ();
    g_memory_input_stream_add_data (G_MEMORY_INPUT_STREAM (priv->compressed_input_stream),
                                    gz_magic, 2, NULL);
}

/**
 * rsvg_handle_write:
 * @handle: an #RsvgHandle
 * @buf: (array length=count) (element-type guchar): pointer to svg data
 * @count: length of the @buf buffer in bytes
 * @error: (allow-none): a location to store a #GError, or %NULL
 *
 * Loads the next @count bytes of the image.  This will return %TRUE if the data
 * was loaded successful, and %FALSE if an error occurred.  In the latter case,
 * the loader will be closed, and will not accept further writes. If %FALSE is
 * returned, @error will be set to an error from the #RsvgError domain. Errors
 * from #GIOErrorEnum are also possible.
 *
 * Returns: %TRUE on success, or %FALSE on error
 **/
gboolean
rsvg_handle_write (RsvgHandle * handle, const guchar * buf, gsize count, GError ** error)
{
    RsvgHandlePrivate *priv;

    rsvg_return_val_if_fail (handle, FALSE, error);
    priv = handle->priv;

    rsvg_return_val_if_fail (priv->state == RSVG_HANDLE_STATE_START
                             || priv->state == RSVG_HANDLE_STATE_EXPECTING_GZ_1
                             || priv->state == RSVG_HANDLE_STATE_READING_COMPRESSED
                             || priv->state == RSVG_HANDLE_STATE_READING,
                             FALSE,
                             error);

    while (count > 0) {
        switch (priv->state) {
        case RSVG_HANDLE_STATE_START:
            if (buf[0] == GZ_MAGIC_0) {
                priv->state = RSVG_HANDLE_STATE_EXPECTING_GZ_1;
                buf++;
                count--;
            } else {
                priv->state = RSVG_HANDLE_STATE_READING;
                return rsvg_handle_write_impl (handle, buf, count, error);
            }

            break;

        case RSVG_HANDLE_STATE_EXPECTING_GZ_1:
            if (buf[0] == GZ_MAGIC_1) {
                priv->state = RSVG_HANDLE_STATE_READING_COMPRESSED;
                create_compressed_input_stream (handle);
                buf++;
                count--;
            } else {
                priv->state = RSVG_HANDLE_STATE_READING;
                return rsvg_handle_write_impl (handle, buf, count, error);
            }

            break;

        case RSVG_HANDLE_STATE_READING_COMPRESSED:
            g_memory_input_stream_add_data (G_MEMORY_INPUT_STREAM (priv->compressed_input_stream),
                                            g_memdup (buf, count), count, (GDestroyNotify) g_free);
            return TRUE;

        case RSVG_HANDLE_STATE_READING:
            return rsvg_handle_write_impl (handle, buf, count, error);

        default:
            g_assert_not_reached ();
        }
    }

    return TRUE;
}

/**
 * rsvg_handle_close:
 * @handle: a #RsvgHandle
 * @error: (allow-none): a location to store a #GError, or %NULL
 *
 * Closes @handle, to indicate that loading the image is complete.  This will
 * return %TRUE if the loader closed successfully.  Note that @handle isn't
 * freed until @g_object_unref is called.
 *
 * Returns: %TRUE on success, or %FALSE on error
 **/
gboolean
rsvg_handle_close (RsvgHandle * handle, GError ** error)
{
    RsvgHandlePrivate *priv;
    gboolean result;

    rsvg_return_val_if_fail (handle, FALSE, error);
    priv = handle->priv;

    if (priv->state == RSVG_HANDLE_STATE_CLOSED_OK
        || priv->state == RSVG_HANDLE_STATE_CLOSED_ERROR) {
        /* closing is idempotent */
        return TRUE;
    }

    if (priv->state == RSVG_HANDLE_STATE_READING_COMPRESSED) {
        gboolean ret;

        /* FIXME: when using rsvg_handle_write()/rsvg_handle_close(), as opposed to using the
         * stream functions, for compressed SVGs we buffer the whole compressed file in memory
         * and *then* uncompress/parse it here.
         *
         * We should make it so that the incoming data is decompressed and parsed on the fly.
         */
        priv->state = RSVG_HANDLE_STATE_START;
        ret = rsvg_handle_read_stream_sync (handle, priv->compressed_input_stream, NULL, error);
        g_object_unref (priv->compressed_input_stream);
        priv->compressed_input_stream = NULL;

        return ret;
    }

    result = rsvg_handle_close_impl (handle, error);

    if (result) {
        priv->state = RSVG_HANDLE_STATE_CLOSED_OK;
    } else {
        priv->state = RSVG_HANDLE_STATE_CLOSED_ERROR;
    }

    return result;
}

/**
 * rsvg_handle_read_stream_sync:
 * @handle: a #RsvgHandle
 * @stream: a #GInputStream
 * @cancellable: (allow-none): a #GCancellable, or %NULL
 * @error: (allow-none): a location to store a #GError, or %NULL
 *
 * Reads @stream and writes the data from it to @handle.
 *
 * If @cancellable is not %NULL, then the operation can be cancelled by
 * triggering the cancellable object from another thread. If the
 * operation was cancelled, the error %G_IO_ERROR_CANCELLED will be
 * returned.
 *
 * Returns: %TRUE if reading @stream succeeded, or %FALSE otherwise
 *   with @error filled in
 *
 * Since: 2.32
 */
gboolean
rsvg_handle_read_stream_sync (RsvgHandle   *handle,
                              GInputStream *stream,
                              GCancellable *cancellable,
                              GError      **error)
{
    RsvgHandlePrivate *priv;
    int result;
    GError *err = NULL;
    gboolean res = FALSE;
    const guchar *buf;
    gssize num_read;

    g_return_val_if_fail (RSVG_IS_HANDLE (handle), FALSE);
    g_return_val_if_fail (G_IS_INPUT_STREAM (stream), FALSE);
    g_return_val_if_fail (cancellable == NULL || G_IS_CANCELLABLE (cancellable), FALSE);
    g_return_val_if_fail (error == NULL || *error == NULL, FALSE);

    priv = handle->priv;

    g_return_val_if_fail (priv->state == RSVG_HANDLE_STATE_START, FALSE);

    /* detect zipped streams */
    stream = g_buffered_input_stream_new (stream);
    num_read = g_buffered_input_stream_fill (G_BUFFERED_INPUT_STREAM (stream), 2, cancellable, error);
    if (num_read < 2) {
        g_object_unref (stream);
        priv->state = RSVG_HANDLE_STATE_CLOSED_ERROR;
        if (num_read < 0) {
            g_assert (error == NULL || *error != NULL);
        } else {
            g_set_error (error, rsvg_error_quark (), RSVG_ERROR_FAILED,
                         _("Input file is too short"));
        }

        return FALSE;
    }
    buf = g_buffered_input_stream_peek_buffer (G_BUFFERED_INPUT_STREAM (stream), NULL);
    if ((buf[0] == GZ_MAGIC_0) && (buf[1] == GZ_MAGIC_1)) {
        GConverter *converter;
        GInputStream *conv_stream;

        converter = G_CONVERTER (g_zlib_decompressor_new (G_ZLIB_COMPRESSOR_FORMAT_GZIP));
        conv_stream = g_converter_input_stream_new (stream, converter);
        g_object_unref (converter);
        g_object_unref (stream);

        stream = conv_stream;
    }

    priv->error = &err;
    priv->cancellable = cancellable ? g_object_ref (cancellable) : NULL;

    g_assert (handle->priv->ctxt == NULL);
    handle->priv->ctxt = create_xml_stream_parser (handle,
                                                   stream,
                                                   cancellable,
                                                   &err);

    if (!handle->priv->ctxt) {
        if (err) {
            g_propagate_error (error, err);
        }

        goto out;
    }

    result = xmlParseDocument (priv->ctxt);
    if (result != 0) {
        if (err)
            g_propagate_error (error, err);
        else
            rsvg_set_error (error, handle->priv->ctxt);

        goto out;
    }

    if (err != NULL) {
        g_propagate_error (error, err);
        goto out;
    }

    res = TRUE;

  out:

    priv->ctxt = rsvg_free_xml_parser_and_doc (priv->ctxt);

    g_object_unref (stream);

    priv->error = NULL;
    g_clear_object (&priv->cancellable);

    if (res) {
        priv->state = RSVG_HANDLE_STATE_CLOSED_OK;
    } else {
        priv->state = RSVG_HANDLE_STATE_CLOSED_ERROR;
    }

    return res;
}

/**
 * rsvg_handle_new_from_gfile_sync:
 * @file: a #GFile
 * @flags: flags from #RsvgHandleFlags
 * @cancellable: (allow-none): a #GCancellable, or %NULL
 * @error: (allow-none): a location to store a #GError, or %NULL
 *
 * Creates a new #RsvgHandle for @file.
 *
 * If @cancellable is not %NULL, then the operation can be cancelled by
 * triggering the cancellable object from another thread. If the
 * operation was cancelled, the error %G_IO_ERROR_CANCELLED will be
 * returned.
 *
 * Returns: a new #RsvgHandle on success, or %NULL with @error filled in
 *
 * Since: 2.32
 */
RsvgHandle *
rsvg_handle_new_from_gfile_sync (GFile          *file,
                                 RsvgHandleFlags flags,
                                 GCancellable   *cancellable,
                                 GError        **error)
{
    RsvgHandle *handle;
    GFileInputStream *stream;

    g_return_val_if_fail (G_IS_FILE (file), NULL);
    g_return_val_if_fail (cancellable == NULL || G_IS_CANCELLABLE (cancellable), NULL);
    g_return_val_if_fail (error == NULL || *error == NULL, NULL);

    stream = g_file_read (file, cancellable, error);
    if (stream == NULL)
        return NULL;

    handle = rsvg_handle_new_from_stream_sync (G_INPUT_STREAM (stream), file,
                                               flags, cancellable, error);
    g_object_unref (stream);

    return handle;
}

/**
 * rsvg_handle_new_from_stream_sync:
 * @input_stream: a #GInputStream
 * @base_file: (allow-none): a #GFile, or %NULL
 * @flags: flags from #RsvgHandleFlags
 * @cancellable: (allow-none): a #GCancellable, or %NULL
 * @error: (allow-none): a location to store a #GError, or %NULL
 *
 * Creates a new #RsvgHandle for @stream.
 *
 * If @cancellable is not %NULL, then the operation can be cancelled by
 * triggering the cancellable object from another thread. If the
 * operation was cancelled, the error %G_IO_ERROR_CANCELLED will be
 * returned.
 *
 * Returns: a new #RsvgHandle on success, or %NULL with @error filled in
 *
 * Since: 2.32
 */
RsvgHandle *
rsvg_handle_new_from_stream_sync (GInputStream   *input_stream,
                                  GFile          *base_file,
                                  RsvgHandleFlags flags,
                                  GCancellable    *cancellable,
                                  GError         **error)
{
    RsvgHandle *handle;

    g_return_val_if_fail (G_IS_INPUT_STREAM (input_stream), NULL);
    g_return_val_if_fail (base_file == NULL || G_IS_FILE (base_file), NULL);
    g_return_val_if_fail (cancellable == NULL || G_IS_CANCELLABLE (cancellable), NULL);
    g_return_val_if_fail (error == NULL || *error == NULL, NULL);

    handle = rsvg_handle_new_with_flags (flags);

    if (base_file)
        rsvg_handle_set_base_gfile (handle, base_file);

    if (!rsvg_handle_read_stream_sync (handle, input_stream, cancellable, error)) {
        g_object_unref (handle);
        return NULL;
    }

    return handle;
}

/**
 * _rsvg_handle_internal_set_testing:
 * @handle: a #RsvgHandle
 * @testing: Whether to enable testing mode
 *
 * Do not call this function.  This is intended for librsvg's internal
 * test suite only.
 **/
void
rsvg_handle_internal_set_testing (RsvgHandle *handle, gboolean testing)
{
    g_return_if_fail (RSVG_IS_HANDLE (handle));

    handle->priv->is_testing = testing ? TRUE : FALSE;
}

/**
 * rsvg_init:
 *
 * Initializes librsvg
 * Since: 2.9
 * Deprecated: 2.36: Use g_type_init()
 **/
void
rsvg_init (void)
{
    RSVG_G_TYPE_INIT;
}

/**
 * rsvg_term:
 *
 * This function does nothing.
 *
 * Since: 2.9
 * Deprecated: 2.36
 **/
void
rsvg_term (void)
{
}

/**
 * rsvg_cleanup:
 *
 * This function should not be called from normal programs.
 * See xmlCleanupParser() for more information.
 *
 * Since: 2.36
 **/
void
rsvg_cleanup (void)
{
    xmlCleanupParser ();
}

void
rsvg_node_set_atts (RsvgNode * node, RsvgHandle * ctx, RsvgPropertyBag * atts)
{
    node->set_atts (node, ctx, atts);
}

void
rsvg_pop_discrete_layer (RsvgDrawingCtx * ctx)
{
    ctx->render->pop_discrete_layer (ctx);
}

void
rsvg_push_discrete_layer (RsvgDrawingCtx * ctx)
{
    ctx->render->push_discrete_layer (ctx);
}

void
rsvg_drawing_ctx_increase_num_elements_acquired (RsvgDrawingCtx *draw_ctx)
{
    draw_ctx->num_elements_acquired++;
}

/* This is a mitigation for the security-related bugs:
 * https://gitlab.gnome.org/GNOME/librsvg/issues/323
 * https://gitlab.gnome.org/GNOME/librsvg/issues/515
 * 
 * Imagine the XML [billion laughs attack], but done in SVG's terms:
 * 
 * - #323 above creates deeply nested groups of `<use>` elements.
 * The first one references the second one ten times, the second one
 * references the third one ten times, and so on.  In the file given,
 * this causes 10^17 objects to be rendered.  While this does not
 * exhaust memory, it would take a really long time.
 * 
 * - #515 has deeply nested references of `<pattern>` elements.  Each
 * object inside each pattern has an attribute
 * fill="url(#next_pattern)", so the number of final rendered objects
 * grows exponentially.
 * 
 * We deal with both cases by placing a limit on how many references
 * will be resolved during the SVG rendering process, that is,
 * how many `url(#foo)` will be resolved.
 * 
 * [billion laughs attack]: https://bitbucket.org/tiran/defusedxml
 */
gboolean
rsvg_drawing_ctx_limits_exceeded (RsvgDrawingCtx *draw_ctx)
{
    return draw_ctx->num_elements_acquired > 500000;
}

RsvgNode *
rsvg_drawing_ctx_acquire_node_ref (RsvgDrawingCtx * ctx, RsvgNode *node)
{
  if (g_slist_find (ctx->acquired_nodes, node))
    return NULL;

  ctx->acquired_nodes = g_slist_prepend (ctx->acquired_nodes, node);

  return node;
}

/*
 * rsvg_acquire_node:
 * @ctx: The drawing context in use
 * @url: The IRI to lookup
 *
 * Use this function when looking up urls to other nodes. This
 * function does proper recursion checking and thereby avoids
 * infinite loops.
 *
 * Nodes acquired by this function must be released using
 * rsvg_release_node() in reverse acquiring order.
 *
 * Returns: The node referenced by @url or %NULL if the @url
 *          does not reference a node.
 */
RsvgNode *
rsvg_acquire_node (RsvgDrawingCtx * ctx, const char *url)
{
  RsvgNode *node;

  if (url == NULL)
      return NULL;

  rsvg_drawing_ctx_increase_num_elements_acquired (ctx);
  if (rsvg_drawing_ctx_limits_exceeded (ctx))
      return NULL;

  node = rsvg_defs_lookup (ctx->defs, url);
  if (node == NULL)
    return NULL;

  return rsvg_drawing_ctx_acquire_node_ref (ctx, node);
}

/*
 * rsvg_release_node:
 * @ctx: The drawing context the node was acquired from
 * @node: Node to release
 *
 * Releases a node previously acquired via rsvg_acquire_node().
 *
 * if @node is %NULL, this function does nothing.
 */
void
rsvg_release_node (RsvgDrawingCtx * ctx, RsvgNode *node)
{
  if (node == NULL)
    return;

  g_return_if_fail (ctx->acquired_nodes != NULL);
  g_return_if_fail (ctx->acquired_nodes->data == node);

  ctx->acquired_nodes = g_slist_remove (ctx->acquired_nodes, node);
}

void
rsvg_render_path (RsvgDrawingCtx * ctx, const cairo_path_t *path)
{
    ctx->render->render_path (ctx, path);
    rsvg_render_markers (ctx, path);
}

void
rsvg_render_surface (RsvgDrawingCtx * ctx, cairo_surface_t *surface, double x, double y, double w, double h)
{
    /* surface must be a cairo image surface */
    g_return_if_fail (cairo_surface_get_type (surface) == CAIRO_SURFACE_TYPE_IMAGE);

    ctx->render->render_surface (ctx, surface, x, y, w, h);
}

void
rsvg_add_clipping_rect (RsvgDrawingCtx * ctx, double x, double y, double w, double h)
{
    ctx->render->add_clipping_rect (ctx, x, y, w, h);
}

cairo_surface_t *
rsvg_get_surface_of_node (RsvgDrawingCtx * ctx, RsvgNode * drawable, double w, double h)
{
    return ctx->render->get_surface_of_node (ctx, drawable, w, h);
}

void
rsvg_render_free (RsvgRender * render)
{
    render->free (render);
}

void
rsvg_bbox_init (RsvgBbox * self, cairo_matrix_t *affine)
{
    self->virgin = 1;
    self->affine = *affine;
}

void
rsvg_bbox_insert (RsvgBbox * dst, RsvgBbox * src)
{
    cairo_matrix_t affine;
    double xmin, ymin;
    double xmax, ymax;
    int i;

    if (src->virgin)
        return;

    if (!dst->virgin) {
        xmin = dst->rect.x, ymin = dst->rect.y;
        xmax = dst->rect.x + dst->rect.width, ymax = dst->rect.y + dst->rect.height;
    } else {
        xmin = ymin = xmax = ymax = 0;
    }

    affine = dst->affine;
    if (cairo_matrix_invert (&affine) != CAIRO_STATUS_SUCCESS)
      return; //FIXMEchpe correct??

    cairo_matrix_multiply (&affine, &src->affine, &affine);

    for (i = 0; i < 4; i++) {
        double rx, ry, x, y;
        rx = src->rect.x + src->rect.width * (double) (i % 2);
        ry = src->rect.y + src->rect.height * (double) (i / 2);
        x = affine.xx * rx + affine.xy * ry + affine.x0;
        y = affine.yx * rx + affine.yy * ry + affine.y0;
        if (dst->virgin) {
            xmin = xmax = x;
            ymin = ymax = y;
            dst->virgin = 0;
        } else {
            if (x < xmin)
                xmin = x;
            if (x > xmax)
                xmax = x;
            if (y < ymin)
                ymin = y;
            if (y > ymax)
                ymax = y;
        }
    }
    dst->rect.x = xmin;
    dst->rect.y = ymin;
    dst->rect.width = xmax - xmin;
    dst->rect.height = ymax - ymin;
}

void
rsvg_bbox_clip (RsvgBbox * dst, RsvgBbox * src)
{
    cairo_matrix_t affine;
	double xmin, ymin;
	double xmax, ymax;
    int i;

    if (src->virgin)
        return;

    if (!dst->virgin) {
        xmin = dst->rect.x + dst->rect.width, ymin = dst->rect.y + dst->rect.height;
        xmax = dst->rect.x, ymax = dst->rect.y;
    } else {
        xmin = ymin = xmax = ymax = 0;
    }

    affine = dst->affine;
    if (cairo_matrix_invert (&affine) != CAIRO_STATUS_SUCCESS)
      return;

    cairo_matrix_multiply (&affine, &src->affine, &affine);

    for (i = 0; i < 4; i++) {
        double rx, ry, x, y;
        rx = src->rect.x + src->rect.width * (double) (i % 2);
        ry = src->rect.y + src->rect.height * (double) (i / 2);
        x = affine.xx * rx + affine.xy * ry + affine.x0;
        y = affine.yx * rx + affine.yy * ry + affine.y0;
        if (dst->virgin) {
            xmin = xmax = x;
            ymin = ymax = y;
            dst->virgin = 0;
        } else {
            if (x < xmin)
                xmin = x;
            if (x > xmax)
                xmax = x;
            if (y < ymin)
                ymin = y;
            if (y > ymax)
                ymax = y;
        }
    }

    if (xmin < dst->rect.x)
        xmin = dst->rect.x;
    if (ymin < dst->rect.y)
        ymin = dst->rect.y;
    if (xmax > dst->rect.x + dst->rect.width)
        xmax = dst->rect.x + dst->rect.width;
    if (ymax > dst->rect.y + dst->rect.height)
        ymax = dst->rect.y + dst->rect.height;

    dst->rect.x = xmin;
    dst->rect.width = xmax - xmin;
    dst->rect.y = ymin;
    dst->rect.height = ymax - ymin;
}

void
_rsvg_push_view_box (RsvgDrawingCtx * ctx, double w, double h)
{
    RsvgViewBox *vb = g_new (RsvgViewBox, 1);
    *vb = ctx->vb;
    ctx->vb_stack = g_slist_prepend (ctx->vb_stack, vb);
    ctx->vb.rect.width = w;
    ctx->vb.rect.height = h;
}

void
_rsvg_pop_view_box (RsvgDrawingCtx * ctx)
{
    ctx->vb = *((RsvgViewBox *) ctx->vb_stack->data);
    g_free (ctx->vb_stack->data);
    ctx->vb_stack = g_slist_delete_link (ctx->vb_stack, ctx->vb_stack);
}

void
rsvg_return_if_fail_warning (const char *pretty_function, const char *expression, GError ** error)
{
    g_set_error (error, RSVG_ERROR, 0, _("%s: assertion `%s' failed"), pretty_function, expression);
}

gboolean
rsvg_allow_load (GFile       *base_gfile,
                 const char  *uri,
                 GError     **error)
{
    GFile *base;
    char *path, *dir;
    char *scheme = NULL, *cpath = NULL, *cdir = NULL;

    g_assert (error == NULL || *error == NULL);

    scheme = g_uri_parse_scheme (uri);

    /* Not a valid URI */
    if (scheme == NULL)
        goto deny;

    /* Allow loads of data: from any location */
    if (g_str_equal (scheme, "data"))
        goto allow;

    /* No base to compare to? */
    if (base_gfile == NULL)
        goto deny;

    /* Deny loads from differing URI schemes */
    if (!g_file_has_uri_scheme (base_gfile, scheme))
        goto deny;

    /* resource: is allowed to load anything from other resources */
    if (g_str_equal (scheme, "resource"))
        goto allow;

    /* Non-file: isn't allowed to load anything */
    if (!g_str_equal (scheme, "file"))
        goto deny;

    base = g_file_get_parent (base_gfile);
    if (base == NULL)
        goto deny;

    dir = g_file_get_path (base);
    g_object_unref (base);

    cdir = realpath (dir, NULL);
    g_free (dir);
    if (cdir == NULL)
        goto deny;

    path = g_filename_from_uri (uri, NULL, NULL);
    if (path == NULL)
        goto deny;

    cpath = realpath (path, NULL);
    g_free (path);

    if (cpath == NULL)
        goto deny;

    /* Now check that @cpath is below @cdir */
    if (!g_str_has_prefix (cpath, cdir) ||
        cpath[strlen (cdir)] != G_DIR_SEPARATOR)
        goto deny;

    /* Allow load! */

 allow:
    g_free (scheme);
    free (cpath);
    free (cdir);
    return TRUE;

 deny:
    g_free (scheme);
    free (cpath);
    free (cdir);

    g_set_error (error, G_IO_ERROR, G_IO_ERROR_PERMISSION_DENIED,
                 "File may not link to URI \"%s\"", uri);
    return FALSE;
}

char *
rsvg_handle_resolve_uri (RsvgHandle *handle,
                         const char *uri)
{
    RsvgHandlePrivate *priv = handle->priv;
    char *scheme, *resolved_uri;
    GFile *base, *resolved;

    if (uri == NULL)
        return NULL;

    scheme = g_uri_parse_scheme (uri);
    if (scheme != NULL ||
        priv->base_gfile == NULL ||
        (base = g_file_get_parent (priv->base_gfile)) == NULL) {
        g_free (scheme);
        return g_strdup (uri);
    }

    resolved = g_file_resolve_relative_path (base, uri);
    resolved_uri = g_file_get_uri (resolved);

    g_free (scheme);
    g_object_unref (base);
    g_object_unref (resolved);

    return resolved_uri;
}

char * 
_rsvg_handle_acquire_data (RsvgHandle *handle,
                           const char *url,
                           char **content_type,
                           gsize *len,
                           GError **error)
{
    RsvgHandlePrivate *priv = handle->priv;
    char *uri;
    char *data;

    uri = rsvg_handle_resolve_uri (handle, url);

    if (rsvg_allow_load (priv->base_gfile, uri, error)) {
        data = _rsvg_io_acquire_data (uri,
                                      rsvg_handle_get_base_uri (handle),
                                      content_type,
                                      len,
                                      handle->priv->cancellable,
                                      error);
    } else {
        data = NULL;
    }

    g_free (uri);
    return data;
}

GInputStream *
_rsvg_handle_acquire_stream (RsvgHandle *handle,
                             const char *url,
                             char **content_type,
                             GError **error)
{
    RsvgHandlePrivate *priv = handle->priv;
    char *uri;
    GInputStream *stream;

    uri = rsvg_handle_resolve_uri (handle, url);

    if (rsvg_allow_load (priv->base_gfile, uri, error)) {
        stream = _rsvg_io_acquire_stream (uri,
                                          rsvg_handle_get_base_uri (handle),
                                          content_type,
                                          handle->priv->cancellable,
                                          error);
    } else {
        stream = NULL;
    }

    g_free (uri);
    return stream;
}

/* Frees the ctxt and its ctxt->myDoc - libxml2 doesn't free them together
 * http://xmlsoft.org/html/libxml-parser.html#xmlFreeParserCtxt
 *
 * Returns NULL.
 */
xmlParserCtxtPtr
rsvg_free_xml_parser_and_doc (xmlParserCtxtPtr ctxt)
{
    if (ctxt) {
        if (ctxt->myDoc) {
            xmlFreeDoc (ctxt->myDoc);
            ctxt->myDoc = NULL;
        }

        xmlFreeParserCtxt (ctxt);
    }

    return NULL;
}