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gimp/plug-ins/metadata/xmp-parse.c

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/* xmp-parse.c - simple parser for XMP metadata
*
* Copyright (C) 2004-2007, Raphaël Quinet <raphael@gimp.org>
*
* This library is free software: you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*/
/* This code implements a simple parser for XMP metadata. Its API is
* based on the one provided by GMarkupParser (part of Glib).
*
* This is not a full RDF parser: it shares some of the limitations
* inherited from glib (UTF-8 only, no special entities) and supports
* RDF only to the extent needed for XMP. XMP defines several
* "schemas" containing a list of "properties". Each property in a
* schema has one value, which can be a simple type (e.g., integer or
* text) or a structured type (rdf:Alt, rdf:Bag, rdf:Seq). As there
* is no need to support a much deeper nesting of elements, this
* parser does not try to maintain an arbitrarily large stack of
* elements. Also, it does not support RDF features that are
* forbidden by the XMP specs, such as rdf:parseType="Litteral".
*
* The design goals for this parser are: support all RDF features
* needed for XMP (at least the features explicitely described in the
* XMP spec), be tolerant in case unknown elements or attributes are
* found, be as simple as possible, avoid building a DOM tree.
*
* TODO:
* - support UCS-2 and UCS-4 besides UTF-8 (copy and convert the data)
* - write a decent scanner for finding <?xpacket...?> as recommended
* in the XMP specification (including support for UCS-2 and UCS-4)
* - provide an API for passing unknown elements or tags to the caller
* - think about re-writing this using a better XML parser (expat?)
* instead of the GMarkup parser
*/
#ifndef WITHOUT_GIMP
# include "config.h"
# include <string.h>
# include "libgimp/stdplugins-intl.h"
#else
# include <string.h>
# define _(String) (String)
# define N_(String) (String)
#endif
#include "base64.h"
#include "xmp-parse.h"
GQuark
xmp_parse_error_quark (void)
{
static GQuark error_quark = 0;
if (error_quark == 0)
error_quark = g_quark_from_static_string ("xmp-parse-error-quark");
return error_quark;
}
/* The current version of XMP (January 2004) is relatively simple in
* that only a few elements (<rdf:Description>, <rdf:Alt>, <rdf:Bag>,
* <rdf:Seq>) may include other elements and no deep nesting is
* allowed. As a result, it is possible to include all allowed
* combinations directly into the state instead of having to maintain
* a separate stack besides the simple state enum. There is only a
* 1-element stack (saved_state) used for some special cases such as
* when skipping unknown tags or parsing a property with qualifiers.
*
* Here is a quick overview of the structure of an XMP document and
* the corresponding state after reading each element. Depending on
* the contents of each property, we can have the following cases
* that are summarized as STATE_INSIDE... below:
* - structured types can use any valid combination of the states
* between STATE_INSIDE_QDESC and STATE_INSIDE_SEQ_LI_RSC;
* - simple property types contain some text and no other element so
* the only state will be STATE_INSIDE_PROPERTY while reading that
* text;
* - if the shorthand notation is used for some simple properties,
* then they will be written as attributes of a top level
* rdf:Description instead of being a separate element, so the
* state will not go deeper than STATE_INSIDE_TOPLEVEL_DESC.
*
* (init) STATE_START
* <?xpacket begin='' id='...'?> STATE_INSIDE_XPACKET
* <x:xmpmeta xmlns:x='adobe:ns:meta/'> STATE_INSIDE_XMPMETA
* <rdf:RDF xmlns:rdf='...'> STATE_INSIDE_RDF
* <rdf:Description rdf:about='' ...> STATE_INSIDE_TOPLEVEL_DESC
* <foo:bar> STATE_INSIDE_PROPERTY
* ... (simple or structured property) STATE_INSIDE...
* </foo:bar> STATE_INSIDE_TOPLEVEL_DESC
* <foo:baz> STATE_INSIDE_PROPERTY
* ... (simple or structured property) STATE_INSIDE...
* </foo:baz> STATE_INSIDE_TOPLEVEL_DESC
* </rdf:Description> STATE_INSIDE_RDF
* <rdf:Description ...> STATE_INSIDE_TOPLEVEL_DESC
* ... (some properties) STATE_INSIDE_PROPERTY
* </rdf:Description> STATE_INSIDE_RDF
* ...
* </rdf:RDF> STATE_AFTER_RDF
* </x:xmpmeta> STATE_AFTER_XMPMETA
* <?xpacket end='r'?> STATE_AFTER_XPACKET
*
* Note: The abbreviation QDESC is used for the properties with
* qualifiers (when <rdf:Description> is used deeper than at the top
* level inside <rdf:RDF>). In that case, QDESC_VALUE contains the
* value of the property and QDESC_QUAL is used for each of the
* optional qualifiers (which are currently ignored).
*/
typedef enum
{
STATE_START,
STATE_INSIDE_XPACKET,
STATE_INSIDE_XMPMETA,
STATE_INSIDE_RDF,
STATE_INSIDE_TOPLEVEL_DESC,
STATE_INSIDE_PROPERTY,
STATE_INSIDE_QDESC,
STATE_INSIDE_QDESC_VALUE,
STATE_INSIDE_QDESC_QUAL,
STATE_INSIDE_STRUCT_ADD_NS,
STATE_INSIDE_STRUCT,
STATE_INSIDE_STRUCT_ELEMENT,
STATE_INSIDE_ALT,
STATE_INSIDE_ALT_LI,
STATE_INSIDE_ALT_LI_RSC,
STATE_INSIDE_ALT_LI_RSC_IMG,
STATE_INSIDE_BAG,
STATE_INSIDE_BAG_LI,
STATE_INSIDE_BAG_LI_RSC,
STATE_INSIDE_SEQ,
STATE_INSIDE_SEQ_LI,
STATE_INSIDE_SEQ_LI_RSC,
STATE_AFTER_RDF,
STATE_AFTER_XMPMETA,
STATE_AFTER_XPACKET,
STATE_SKIPPING_UNKNOWN_ELEMENTS,
STATE_SKIPPING_IGNORED_ELEMENTS,
STATE_ERROR
} XMPParseState;
typedef struct
{
gint depth;
gchar *uri;
gchar *prefix;
gint prefix_len;
gpointer ns_user_data;
} XMLNameSpace;
struct _XMPParseContext
{
const XMPParser *parser;
XMPParseFlags flags;
gpointer user_data;
GDestroyNotify user_data_dnotify;
XMPParseState state;
gint depth;
GSList *namespaces;
gchar *xmp_prefix;
guint xmp_prefix_len;
gchar *rdf_prefix;
guint rdf_prefix_len;
gchar *property;
XMLNameSpace *property_ns;
XMPParseType property_type;
gchar **prop_value;
gint prop_cur_value;
gint prop_max_value;
gboolean prop_missing_value;
/* used when skipping tags, or inside a struct or property qualifier */
XMPParseState saved_state;
gint saved_depth;
GMarkupParseContext *markup_context;
};
#ifdef DEBUG_XMP_PARSER
static const gchar * const state_names[] =
{
"START",
"INSIDE_XPACKET",
"INSIDE_XMPMETA",
"INSIDE_RDF",
"INSIDE_TOPLEVEL_DESC",
"INSIDE_PROPERTY",
"INSIDE_QDESC",
"INSIDE_QDESC_VALUE",
"INSIDE_QDESC_QUAL",
"INSIDE_STRUCT_ADD_NS",
"INSIDE_STRUCT",
"INSIDE_STRUCT_ELEMENT",
"INSIDE_ALT",
"INSIDE_ALT_LI",
"INSIDE_ALT_LI_RSC",
"INSIDE_ALT_LI_RSC_IMG",
"INSIDE_BAG",
"INSIDE_BAG_LI",
"INSIDE_BAG_LI_RSC",
"INSIDE_SEQ",
"INSIDE_SEQ_LI",
"INSIDE_SEQ_LI_RSC",
"AFTER_RDF",
"AFTER_XMPMETA",
"AFTER_XPACKET",
"SKIPPING_UNKNOWN_ELEMENTS",
"SKIPPING_IGNORED_ELEMENTS",
"ERROR",
};
#endif
/* report an error and propagate it */
static void
parse_error (XMPParseContext *context,
GError **error,
XMPParseError code,
const gchar *format,
...)
{
GError *tmp_error;
if (code == XMP_ERROR_NO_XPACKET)
tmp_error = g_error_new (XMP_PARSE_ERROR, code,
_("Error: No XMP packet found"));
else
{
gchar *s;
va_list args;
gint line_number;
gint char_number;
va_start (args, format);
s = g_strdup_vprintf (format, args);
va_end (args);
g_markup_parse_context_get_position (context->markup_context,
&line_number,
&char_number);
tmp_error = g_error_new (XMP_PARSE_ERROR, code,
_("Error on line %d char %d: %s"),
line_number, char_number, s);
g_free (s);
}
context->state = STATE_ERROR;
if (context->parser->error)
(*context->parser->error) (context, tmp_error, context->user_data);
g_propagate_error (error, tmp_error);
}
/* report an error if an unexpected element is found in the wrong context */
static void
parse_error_element (XMPParseContext *context,
GError **error,
const gchar *expected_element,
gboolean optional,
const gchar *found_element)
{
if (optional == TRUE)
parse_error (context, error, XMP_ERROR_UNEXPECTED_ELEMENT,
_("Expected text or optional element <%s>, found <%s> instead"),
expected_element, found_element);
else
parse_error (context, error, XMP_ERROR_UNEXPECTED_ELEMENT,
_("Expected element <%s>, found <%s> instead"),
expected_element, found_element);
}
/* skip an unknown element (unknown property) and its contents */
static void
unknown_element (XMPParseContext *context,
GError **error,
const gchar *element_name)
{
#ifdef DEBUG_XMP_PARSER
g_print ("XMP: SKIPPING %s\n", element_name);
#endif
if (context->flags & XMP_FLAG_NO_UNKNOWN_ELEMENTS)
parse_error (context, error, XMP_ERROR_UNKNOWN_ELEMENT,
_("Unknown element <%s>"),
element_name);
else
{
context->saved_depth = context->depth;
context->saved_state = context->state;
context->state = STATE_SKIPPING_UNKNOWN_ELEMENTS;
}
}
/* skip and element and all other elements that it may contain */
static void
ignore_element (XMPParseContext *context)
{
context->saved_depth = context->depth;
context->saved_state = context->state;
context->state = STATE_SKIPPING_IGNORED_ELEMENTS;
}
/* skip an unknown attribute (or abort if flags forbid unknown attributes) */
static void
unknown_attribute (XMPParseContext *context,
GError **error,
const gchar *element_name,
const gchar *attribute_name,
const gchar *attribute_value)
{
if (context->flags & XMP_FLAG_NO_UNKNOWN_ATTRIBUTES)
parse_error (context, error, XMP_ERROR_UNKNOWN_ATTRIBUTE,
_("Unknown attribute \"%s\"=\"%s\" in element <%s>"),
attribute_name, attribute_value, element_name);
#ifdef DEBUG_XMP_PARSER
g_print ("skipping unknown attribute \"%s\"=\"%s\" in element <%s>\n",
attribute_name, attribute_value, element_name);
#endif
}
static gboolean
is_whitespace_string (const gchar *string)
{
const gchar *p;
if (string == NULL)
return TRUE;
/* XML accepts only 4 ASCII chars as whitespace and no other UNICODE chars */
for (p = string; *p; ++p)
if (*p != ' ' && *p != '\t' && *p != '\r' && *p != '\n')
return FALSE;
return TRUE;
}
/* new namespace/schema seen - add it to the list of namespaces */
static void
push_namespace (XMPParseContext *context,
const gchar *uri,
const gchar *prefix,
GError **error)
{
XMLNameSpace *ns;
if (! strcmp (uri, "adobe:ns:meta/"))
{
g_free (context->xmp_prefix);
context->xmp_prefix = g_strdup (prefix); /* XMP recommends "x:" */
context->xmp_prefix_len = strlen (prefix);
return;
}
if (! strcmp (uri, "http://www.w3.org/1999/02/22-rdf-syntax-ns#"))
{
g_free (context->rdf_prefix);
context->rdf_prefix = g_strdup (prefix); /* XMP recommends "rdf:" */
context->rdf_prefix_len = strlen (prefix);
return;
}
ns = g_slice_new0 (XMLNameSpace);
ns->depth = context->depth;
ns->uri = g_strdup (uri);
ns->prefix = g_strdup (prefix);
ns->prefix_len = strlen (prefix);
context->namespaces = g_slist_prepend (context->namespaces, ns);
if (context->parser->start_schema)
ns->ns_user_data = (*context->parser->start_schema) (context,
ns->uri,
ns->prefix,
context->user_data,
error);
else
ns->ns_user_data = NULL;
}
/* free all namespaces that are deeper than the current element depth */
static void
pop_namespaces (XMPParseContext *context,
GError **error)
{
XMLNameSpace *ns;
if (context->namespaces == NULL)
return;
ns = context->namespaces->data;
while (ns->depth >= context->depth)
{
if (context->parser->end_schema)
(*context->parser->end_schema) (context,
ns->ns_user_data,
context->user_data,
error);
g_free (ns->uri);
g_free (ns->prefix);
g_slice_free (XMLNameSpace, ns);
context->namespaces = g_slist_delete_link (context->namespaces,
context->namespaces);
if (context->namespaces == NULL)
break;
ns = context->namespaces->data;
}
}
/* checks if an element name starts with the prefix of the given namespace */
static gboolean
has_ns_prefix (const gchar *name,
XMLNameSpace *ns)
{
if (ns == NULL)
return FALSE;
return ((strncmp (name, ns->prefix, ns->prefix_len) == 0)
&& (name[ns->prefix_len] == ':'));
}
/* checks if an element or attribute matches a target with the given prefix */
static gboolean
matches_with_prefix (const gchar *name,
const gchar *prefix,
guint prefix_len,
const gchar *target_name)
{
if (prefix == NULL)
return FALSE;
return ((strncmp (name, prefix, prefix_len) == 0)
&& (strlen (name) > prefix_len + 1)
&& (name[prefix_len] == ':')
&& (strcmp (name + prefix_len + 1, target_name) == 0));
}
/* checks if an element or attribute matches a target in the RDF namespace */
static gboolean
matches_rdf (const gchar *name,
XMPParseContext *context,
const gchar *target_name)
{
if (context->rdf_prefix != NULL)
return matches_with_prefix (name,
context->rdf_prefix,
context->rdf_prefix_len,
target_name);
else
return matches_with_prefix (name, "rdf", 3, target_name);
}
/* add a new property to the schema referenced by its prefix */
/* the value(s) of the property will be added later by add_property_value() */
static XMLNameSpace *
new_property_in_ns (XMPParseContext *context,
const gchar *element_name)
{
GSList *list;
XMLNameSpace *ns;
g_return_val_if_fail (context->property == NULL, NULL);
g_return_val_if_fail (context->prop_cur_value == -1, NULL);
/* element_name is a new property if it starts with a known prefix */
for (list = context->namespaces;
list != NULL;
list = g_slist_next (list))
{
ns = list->data;
if (has_ns_prefix (element_name, ns))
{
context->property = g_strdup (element_name + ns->prefix_len + 1);
context->property_type = XMP_PTYPE_UNKNOWN;
context->property_ns = ns;
context->prop_missing_value = FALSE;
return ns;
}
}
return NULL;
}
/* store a value for the current property - if the element containing the */
/* value is being parsed but the actual value has not been seen yet, then */
/* call this function with a NULL value so that its data structure is */
/* allocated now; it will be updated later with update_property_value() */
static void
add_property_value (XMPParseContext *context,
XMPParseType type,
gchar *name,
gchar *value)
{
g_return_if_fail (context->property != NULL);
if (type == XMP_PTYPE_TEXT || type == XMP_PTYPE_RESOURCE)
g_return_if_fail (context->prop_cur_value < 0);
if (context->property_type != type)
{
/* make sure that we are not mixing different types in this property */
g_return_if_fail (context->property_type == XMP_PTYPE_UNKNOWN);
context->property_type = type;
}
if (context->prop_cur_value + 3 >= context->prop_max_value)
{
context->prop_max_value += 10;
context->prop_value = g_realloc (context->prop_value,
sizeof (gchar *)
* context->prop_max_value);
}
/* some types store a name and a value; most others store only a value */
if (type == XMP_PTYPE_ALT_LANG
|| type == XMP_PTYPE_STRUCTURE
|| type == XMP_PTYPE_ALT_THUMBS) /* for thumbnails, name is the size */
{
context->prop_cur_value++;
context->prop_value[context->prop_cur_value] = name;
}
else
g_assert (name == NULL);
context->prop_cur_value++;
context->prop_value[context->prop_cur_value] = value;
context->prop_value[context->prop_cur_value + 1] = NULL;
/* if value was NULL, then we must update it later */
context->prop_missing_value = (value == NULL);
}
/* update a value that has been allocated but not stored yet */
static void
update_property_value (XMPParseContext *context,
gchar *value)
{
g_return_if_fail (context->property != NULL);
g_return_if_fail (context->prop_cur_value >= 0);
g_return_if_fail (context->prop_missing_value == TRUE);
context->prop_value[context->prop_cur_value] = value;
context->prop_missing_value = FALSE;
}
/* invoke the 'set_property' callback and free the temporary structures */
static void
propagate_property (XMPParseContext *context,
GError **error)
{
g_return_if_fail (context->property != NULL);
g_return_if_fail (context->prop_cur_value >= 0);
if (context->parser->set_property)
(*context->parser->set_property) (context,
context->property,
context->property_type,
(const gchar **)(context->prop_value),
context->property_ns->ns_user_data,
context->user_data,
error);
if (! (context->flags & XMP_FLAG_DEFER_VALUE_FREE))
{
while (context->prop_cur_value >= 0)
{
g_free (context->prop_value[context->prop_cur_value]);
context->prop_cur_value--;
}
g_free (context->prop_value);
}
context->prop_value = NULL;
context->prop_cur_value = -1;
context->prop_max_value = 0;
g_free (context->property);
context->property = NULL;
context->property_ns = NULL;
}
/* called from the GMarkupParser */
static void
start_element_handler (GMarkupParseContext *markup_context,
const gchar *element_name,
const gchar **attribute_names,
const gchar **attribute_values,
gpointer user_data,
GError **error)
{
XMPParseContext *context = user_data;
gint attr;
#ifdef DEBUG_XMP_PARSER
g_print ("[%25s/%17s] %d <%s>\n",
state_names[context->state],
(context->saved_state == STATE_ERROR
? "-"
: state_names[context->saved_state]),
context->depth, element_name);
#endif
context->depth++;
for (attr = 0; attribute_names[attr] != NULL; ++attr)
if (g_str_has_prefix (attribute_names[attr], "xmlns:"))
push_namespace (context, attribute_values[attr],
attribute_names[attr] + sizeof ("xmlns:") - 1, error);
switch (context->state)
{
case STATE_INSIDE_XPACKET:
if (! strcmp (element_name, "x:xmpmeta")
|| ! strcmp (element_name, "x:xapmeta")
|| matches_with_prefix (element_name, context->xmp_prefix,
context->xmp_prefix_len, "xmpmeta"))
context->state = STATE_INSIDE_XMPMETA;
else if (matches_rdf (element_name, context, "RDF"))
{
/* the x:xmpmeta element is missing, but this is allowed */
context->depth++;
context->state = STATE_INSIDE_RDF;
}
else
parse_error_element (context, error, "x:xmpmeta",
FALSE, element_name);
break;
case STATE_INSIDE_XMPMETA:
if (matches_rdf (element_name, context, "RDF"))
context->state = STATE_INSIDE_RDF;
else
parse_error_element (context, error, "rdf:RDF",
FALSE, element_name);
break;
case STATE_INSIDE_RDF:
if (matches_rdf (element_name, context, "Description"))
{
XMLNameSpace *ns;
gboolean about_seen = FALSE;
context->state = STATE_INSIDE_TOPLEVEL_DESC;
for (attr = 0; attribute_names[attr] != NULL; ++attr)
{
if (matches_rdf (attribute_names[attr], context, "about")
|| ! strcmp (attribute_names[attr], "about") /* old style */)
about_seen = TRUE;
else if (g_str_has_prefix (attribute_names[attr], "xmlns"))
; /* the namespace has already been pushed on the stack */
else
{
ns = new_property_in_ns (context, attribute_names[attr]);
if (ns != NULL)
{
/* RDF shorthand notation */
add_property_value (context, XMP_PTYPE_TEXT, NULL,
g_strdup (attribute_values[attr]));
propagate_property (context, error);
}
else
unknown_attribute (context, error, element_name,
attribute_names[attr],
attribute_values[attr]);
}
}
if ((about_seen == FALSE)
&& (context->flags & XMP_FLAG_NO_MISSING_ABOUT))
parse_error (context, error, XMP_ERROR_MISSING_ABOUT,
_("Required attribute rdf:about missing in <%s>"),
element_name);
}
else
parse_error_element (context, error, "rdf:Description",
FALSE, element_name);
break;
case STATE_INSIDE_TOPLEVEL_DESC:
{
XMLNameSpace *ns;
ns = new_property_in_ns (context, element_name);
if (ns != NULL)
{
context->state = STATE_INSIDE_PROPERTY;
for (attr = 0; attribute_names[attr] != NULL; ++attr)
{
if (matches_rdf (attribute_names[attr], context, "resource"))
add_property_value (context, XMP_PTYPE_RESOURCE, NULL,
g_strdup (attribute_values[attr]));
else if (matches_rdf (attribute_names[attr], context,
"parseType")
&& ! strcmp (attribute_values[attr], "Resource"))
{
context->saved_state = STATE_INSIDE_TOPLEVEL_DESC;
context->state = STATE_INSIDE_STRUCT_ADD_NS;
}
else
unknown_attribute (context, error, element_name,
attribute_names[attr],
attribute_values[attr]);
}
}
else
unknown_element (context, error, element_name);
}
break;
case STATE_INSIDE_PROPERTY:
if (matches_rdf (element_name, context, "Description"))
{
context->saved_state = context->state;
context->state = STATE_INSIDE_QDESC;
for (attr = 0; attribute_names[attr] != NULL; ++attr)
{
if (g_str_has_prefix (attribute_names[attr], "xmlns"))
{
/* this desc. is a structure, not a property qualifier */
context->state = STATE_INSIDE_STRUCT_ADD_NS;
}
else
unknown_attribute (context, error, element_name,
attribute_names[attr],
attribute_values[attr]);
}
}
else if (matches_rdf (element_name, context, "Alt"))
context->state = STATE_INSIDE_ALT;
else if (matches_rdf (element_name, context, "Bag"))
context->state = STATE_INSIDE_BAG;
else if (matches_rdf (element_name, context, "Seq"))
context->state = STATE_INSIDE_SEQ;
else
unknown_element (context, error, element_name);
break;
case STATE_INSIDE_QDESC:
if (matches_rdf (element_name, context, "value"))
context->state = STATE_INSIDE_QDESC_VALUE;
else
context->state = STATE_INSIDE_QDESC_QUAL;
break;
case STATE_INSIDE_STRUCT_ADD_NS:
case STATE_INSIDE_STRUCT:
{
GSList *ns_list;
XMLNameSpace *ns;
gboolean found;
/* compare with namespaces in scope of current rdf:Description */
found = FALSE;
ns_list = context->namespaces;
while (ns_list != NULL)
{
ns = ns_list->data;
if (ns->depth < context->depth - 2)
break;
if (has_ns_prefix (element_name, ns))
{
if (context->state == STATE_INSIDE_STRUCT_ADD_NS)
{
/* first element - save the namespace prefix and uri */
add_property_value (context, XMP_PTYPE_STRUCTURE,
g_strdup (ns->prefix),
g_strdup (ns->uri));
}
context->state = STATE_INSIDE_STRUCT_ELEMENT;
add_property_value (context, XMP_PTYPE_STRUCTURE,
g_strdup (element_name
+ ns->prefix_len + 1),
NULL);
found = TRUE;
break;
}
ns_list = ns_list->next;
}
if (found == FALSE)
unknown_element (context, error, element_name);
}
break;
case STATE_INSIDE_ALT:
if (matches_rdf (element_name, context, "li"))
{
context->state = STATE_INSIDE_ALT_LI;
for (attr = 0; attribute_names[attr] != NULL; ++attr)
{
if (matches_rdf (attribute_names[attr], context, "parseType")
&& ! strcmp (attribute_values[attr], "Resource"))
context->state = STATE_INSIDE_ALT_LI_RSC;
else if (! strcmp (attribute_names[attr], "xml:lang"))
add_property_value (context, XMP_PTYPE_ALT_LANG,
g_strdup (attribute_values[attr]),
NULL);
else
unknown_attribute (context, error, element_name,
attribute_names[attr],
attribute_values[attr]);
}
/* rdf:Alt is not an ordered list, but some broken XMP files use */
/* it instead of rdf:Seq. Workaround: if we did not find some */
/* attributes for the valid cases ALT_LANG or ALT_LI_RSC, then */
/* we pretend that we are parsing a real list (bug #343315). */
if ((context->property_type != XMP_PTYPE_ALT_LANG)
&& (context->state != STATE_INSIDE_ALT_LI_RSC))
add_property_value (context, XMP_PTYPE_ORDERED_LIST,
NULL, NULL);
}
else
parse_error_element (context, error, "rdf:li",
FALSE, element_name);
break;
case STATE_INSIDE_BAG:
if (matches_rdf (element_name, context, "li"))
{
context->state = STATE_INSIDE_BAG_LI;
for (attr = 0; attribute_names[attr] != NULL; ++attr)
{
if (matches_rdf (attribute_names[attr], context, "parseType")
&& ! strcmp (attribute_values[attr], "Resource"))
context->state = STATE_INSIDE_BAG_LI_RSC;
else
unknown_attribute (context, error, element_name,
attribute_names[attr],
attribute_values[attr]);
}
if (context->state != STATE_INSIDE_BAG_LI_RSC)
add_property_value (context, XMP_PTYPE_UNORDERED_LIST,
NULL, NULL);
}
else
parse_error_element (context, error, "rdf:li",
FALSE, element_name);
break;
case STATE_INSIDE_SEQ:
if (matches_rdf (element_name, context, "li"))
{
context->state = STATE_INSIDE_SEQ_LI;
for (attr = 0; attribute_names[attr] != NULL; ++attr)
{
if (matches_rdf (attribute_names[attr], context, "parseType")
&& ! strcmp (attribute_values[attr], "Resource"))
context->state = STATE_INSIDE_SEQ_LI_RSC;
else
unknown_attribute (context, error, element_name,
attribute_names[attr],
attribute_values[attr]);
}
if (context->state != STATE_INSIDE_SEQ_LI_RSC)
add_property_value (context, XMP_PTYPE_ORDERED_LIST,
NULL, NULL);
}
else
parse_error_element (context, error, "rdf:li",
FALSE, element_name);
break;
case STATE_INSIDE_BAG_LI:
case STATE_INSIDE_SEQ_LI:
if (matches_rdf (element_name, context, "Description"))
{
context->saved_state = context->state;
context->state = STATE_INSIDE_QDESC;
}
else
parse_error_element (context, error, "rdf:Description",
TRUE, element_name);
break;
case STATE_INSIDE_ALT_LI_RSC:
/* store the thumbnail image and ignore the other elements */
if (! strcmp (element_name, "xapGImg:image")) /* FIXME */
context->state = STATE_INSIDE_ALT_LI_RSC_IMG;
else if (! strcmp (element_name, "xapGImg:format")
|| ! strcmp (element_name, "xapGImg:width")
|| ! strcmp (element_name, "xapGImg:height"))
ignore_element (context);
else
unknown_element (context, error, element_name);
break;
case STATE_INSIDE_BAG_LI_RSC:
case STATE_INSIDE_SEQ_LI_RSC:
unknown_element (context, error, element_name);
break;
case STATE_SKIPPING_UNKNOWN_ELEMENTS:
case STATE_SKIPPING_IGNORED_ELEMENTS:
break;
default:
parse_error (context, error, XMP_ERROR_PARSE,
_("Nested elements (<%s>) are not allowed in this context"),
element_name);
break;
}
}
/* called from the GMarkupParser */
static void
end_element_handler (GMarkupParseContext *markup_context,
const gchar *element_name,
gpointer user_data,
GError **error)
{
XMPParseContext *context = user_data;
#ifdef DEBUG_XMP_PARSER
g_print ("[%25s/%17s] %d </%s>\n",
state_names[context->state],
(context->saved_state == STATE_ERROR
? "-"
: state_names[context->saved_state]),
context->depth, element_name);
#endif
switch (context->state)
{
case STATE_INSIDE_PROPERTY:
context->state = STATE_INSIDE_TOPLEVEL_DESC;
if (context->property != NULL)
{
if (context->prop_cur_value < 0)
{
/* if not set yet, then property was empty */
add_property_value (context, XMP_PTYPE_TEXT,
NULL, g_strdup (""));
}
propagate_property (context, error);
}
break;
case STATE_INSIDE_STRUCT:
context->state = context->saved_state;
if (context->property != NULL)
propagate_property (context, error);
break;
case STATE_INSIDE_ALT:
case STATE_INSIDE_BAG:
case STATE_INSIDE_SEQ:
if (context->property && context->prop_cur_value < 0)
{
g_free (context->property);
context->property = NULL;
}
context->state = STATE_INSIDE_PROPERTY;
break;
case STATE_INSIDE_QDESC:
context->state = context->saved_state;
break;
case STATE_INSIDE_QDESC_VALUE:
case STATE_INSIDE_QDESC_QUAL:
context->state = STATE_INSIDE_QDESC;
break;
case STATE_INSIDE_STRUCT_ELEMENT:
context->state = STATE_INSIDE_STRUCT;
if ((context->prop_cur_value >= 0)
&& (context->prop_value[context->prop_cur_value] == NULL))
update_property_value (context, g_strdup (""));
break;
case STATE_INSIDE_ALT_LI:
context->state = STATE_INSIDE_ALT;
if ((context->prop_cur_value >= 0)
&& (context->prop_value[context->prop_cur_value] == NULL))
update_property_value (context, g_strdup (""));
break;
case STATE_INSIDE_ALT_LI_RSC:
context->state = STATE_INSIDE_ALT;
break;
case STATE_INSIDE_ALT_LI_RSC_IMG:
context->state = STATE_INSIDE_ALT_LI_RSC;
break;
case STATE_INSIDE_BAG_LI:
case STATE_INSIDE_BAG_LI_RSC:
context->state = STATE_INSIDE_BAG;
break;
case STATE_INSIDE_SEQ_LI:
case STATE_INSIDE_SEQ_LI_RSC:
context->state = STATE_INSIDE_SEQ;
break;
case STATE_INSIDE_TOPLEVEL_DESC:
g_return_if_fail (matches_rdf (element_name, context, "Description"));
context->state = STATE_INSIDE_RDF;
break;
case STATE_INSIDE_RDF:
g_return_if_fail (matches_rdf (element_name, context, "RDF"));
context->state = STATE_AFTER_RDF;
break;
case STATE_AFTER_RDF:
g_return_if_fail (! strcmp (element_name, "x:xmpmeta")
|| ! strcmp (element_name, "x:xapmeta")
|| matches_with_prefix (element_name,
context->xmp_prefix,
context->xmp_prefix_len,
"xmpmeta"));
context->state = STATE_AFTER_XMPMETA;
break;
case STATE_SKIPPING_UNKNOWN_ELEMENTS:
case STATE_SKIPPING_IGNORED_ELEMENTS:
if (context->depth == context->saved_depth)
{
/* resume normal processing */
context->state = context->saved_state;
context->saved_state = STATE_ERROR;
}
break;
default:
parse_error (context, error, XMP_ERROR_PARSE,
_("End of element <%s> not expected in this context"),
element_name);
break;
}
pop_namespaces (context, error);
context->depth--;
}
/* called from the GMarkupParser */
static void
text_handler (GMarkupParseContext *markup_context,
const gchar *text,
gsize text_len,
gpointer user_data,
GError **error)
{
XMPParseContext *context = user_data;
switch (context->state)
{
case STATE_INSIDE_PROPERTY:
if (! is_whitespace_string (text))
add_property_value (context, XMP_PTYPE_TEXT, NULL,
g_strndup (text, text_len));
break;
case STATE_INSIDE_STRUCT_ELEMENT:
case STATE_INSIDE_ALT_LI:
case STATE_INSIDE_BAG_LI:
case STATE_INSIDE_SEQ_LI:
if (! is_whitespace_string (text))
update_property_value (context, g_strndup (text, text_len));
break;
case STATE_INSIDE_ALT_LI_RSC_IMG:
{
gint max_size;
gchar *decoded;
gint decoded_size;
#ifdef DEBUG_XMP_PARSER
/* g_print ("XMP: Pushing text:\n%s\n", text); */
#endif
max_size = text_len - text_len / 4 + 1;
decoded = g_malloc (max_size);
decoded_size = base64_decode (text, text_len, decoded, max_size,
FALSE);
#ifdef DEBUG_XMP_PARSER
if (decoded_size > 0)
{
/* FIXME: remove this debugging code */
/*
FILE *ttt;
ttt = fopen ("/tmp/xmp-thumb.jpg", "wb");
fwrite (decoded, decoded_size, 1, ttt);
fclose (ttt);
*/
g_print ("XMP: Thumb text len: %d (1/4 = %d)\nMax size: %d\nUsed size: %d\n", (int) text_len, (int) text_len / 4, max_size, decoded_size);
}
#endif
if (decoded_size > 0)
{
gint *size_p;
size_p = g_new (gint, 1);
*size_p = decoded_size;
add_property_value (context, XMP_PTYPE_ALT_THUMBS,
(char *) size_p, decoded);
}
else
add_property_value (context, XMP_PTYPE_ALT_THUMBS, NULL, NULL);
}
break;
case STATE_INSIDE_QDESC_VALUE:
if (! is_whitespace_string (text))
{
if (context->saved_state == STATE_INSIDE_PROPERTY)
add_property_value (context, XMP_PTYPE_TEXT, NULL,
g_strndup (text, text_len));
else
update_property_value (context, g_strndup (text, text_len));
}
break;
case STATE_INSIDE_QDESC_QUAL:
#ifdef DEBUG_XMP_PARSER
g_print ("ignoring qualifier for part of \"%s\"[]: \"%.*s\"\n",
context->property,
(int)text_len, text);
#endif
/* FIXME: notify the user? add a way to collect qualifiers? */
break;
case STATE_SKIPPING_UNKNOWN_ELEMENTS:
case STATE_SKIPPING_IGNORED_ELEMENTS:
break;
default:
if (! is_whitespace_string (text))
parse_error (context, error, XMP_ERROR_INVALID_CONTENT,
_("The current element (<%s>) cannot contain text"),
g_markup_parse_context_get_element (markup_context));
break;
}
}
/* called from the GMarkupParser */
static void
passthrough_handler (GMarkupParseContext *markup_context,
const gchar *passthrough_text,
gsize text_len,
gpointer user_data,
GError **error)
{
XMPParseContext *context = user_data;
switch (context->state)
{
case STATE_START:
case STATE_AFTER_XPACKET:
if ((text_len >= 21)
&& (! strncmp (passthrough_text, "<?xpacket begin=", 16)))
context->state = STATE_INSIDE_XPACKET;
else
parse_error (context, error, XMP_ERROR_PARSE,
_("XMP packets must start with <?xpacket begin=...?>"));
break;
case STATE_AFTER_RDF:
/* the x:xmpmeta element is missing */
context->depth--;
pop_namespaces (context, error);
/*fallthrough*/
case STATE_AFTER_XMPMETA:
if ((text_len >= 19)
&& (! strncmp (passthrough_text, "<?xpacket end=", 14)))
context->state = STATE_AFTER_XPACKET;
else
parse_error (context, error, XMP_ERROR_PARSE,
_("XMP packets must end with <?xpacket end=...?>"));
break;
default:
if ((text_len >= 18)
&& (! strncmp (passthrough_text, "<?adobe-", 8)))
; /* ignore things like <?adobe-xap-filters esc="CRLF"?> */
else if (! (context->flags & XMP_FLAG_NO_COMMENTS)
&& (text_len > 7)
&& (! strncmp (passthrough_text, "<!--", 4)))
; /* comments are not allowed in XMP, but let's ignore them */
else
parse_error (context, error, XMP_ERROR_INVALID_COMMENT,
_("XMP cannot contain XML comments or processing instructions"));
break;
}
}
/* called from the GMarkupParser */
static void
error_handler (GMarkupParseContext *markup_context,
GError *error,
gpointer user_data)
{
XMPParseContext *context = user_data;
g_return_if_fail (context != NULL);
context->state = STATE_ERROR;
if ((error->domain != XMP_PARSE_ERROR) && (context->parser->error))
(*context->parser->error) (context, error, context->user_data);
}
static GMarkupParser markup_xmp_parser = {
start_element_handler,
end_element_handler,
text_handler,
passthrough_handler,
error_handler
};
/**
* xmp_parse_context_new:
* @parser: a #XMPParser
* @flags: one or more #XMPParseFlags
* @user_data: user data to pass to #GMarkupParser functions
* @user_data_dnotify: user data destroy notifier called when the
* parse context is freed
*
* Creates a new XMP parse context. A parse context is used to parse
* documents. You can feed any number of documents containing XMP
* metadata into a context, as long as no errors occur; once an error
* occurs, the parse context can't continue to parse text (you have to
* free it and create a new parse context).
*
* Return value: a new #XMPParseContext
**/
XMPParseContext *
xmp_parse_context_new (const XMPParser *parser,
XMPParseFlags flags,
gpointer user_data,
GDestroyNotify user_data_dnotify)
{
XMPParseContext *context;
g_return_val_if_fail (parser != NULL, NULL);
context = g_slice_new0 (XMPParseContext);
context->parser = parser;
context->flags = flags;
context->user_data = user_data;
context->user_data_dnotify = user_data_dnotify;
context->markup_context = g_markup_parse_context_new (&markup_xmp_parser,
0, context, NULL);
context->state = STATE_START;
context->depth = 0;
context->namespaces = NULL;
context->xmp_prefix = NULL;
context->xmp_prefix_len = 0;
context->rdf_prefix = NULL;
context->rdf_prefix_len = 0;
context->property = NULL;
context->property_ns = NULL;
context->prop_value = NULL;
context->prop_cur_value = -1;
context->prop_max_value = 0;
context->prop_missing_value = FALSE;
context->saved_state = STATE_ERROR;
context->saved_depth = 0;
return context;
}
/**
* xmp_parse_context_free:
* @context: a #XMPParseContext
*
* Frees a #XMPParseContext. Cannot be called from inside one of the
* #XMPParser functions.
*
**/
void
xmp_parse_context_free (XMPParseContext *context)
{
g_return_if_fail (context != NULL);
if (context->user_data_dnotify)
(* context->user_data_dnotify) (context->user_data);
g_slist_free (context->namespaces);
g_free (context->xmp_prefix);
g_free (context->rdf_prefix);
if (! (context->flags & XMP_FLAG_DEFER_VALUE_FREE))
{
while (context->prop_cur_value >= 0)
{
g_free (context->prop_value[context->prop_cur_value]);
context->prop_cur_value--;
}
g_free (context->prop_value);
}
g_free (context->property);
g_slice_free (XMPParseContext, context);
}
/**
* xmp_parse_context_parse:
* @context: a #XMPParseContext
* @text: chunk of text to parse
* @text_len: length of @text in bytes
* @error: return location for a #GError
*
* Feed some data to the #XMPParseContext. The data need not be valid
* UTF-8; an error will be signaled if it's invalid. The data need
* not be an entire document; you can feed a document into the parser
* incrementally, via multiple calls to this function. Typically, as
* you receive data from a network connection or file, you feed each
* received chunk of data into this function, aborting the process if
* an error occurs. Once an error is reported, no further data may be
* fed to the #XMPParseContext; all errors are fatal.
*
* Return value: %FALSE if an error occurred, %TRUE on success
**/
gboolean
xmp_parse_context_parse (XMPParseContext *context,
const gchar *text,
gssize text_len,
GError **error)
{
g_return_val_if_fail (context != NULL, FALSE);
g_return_val_if_fail (text != NULL, FALSE);
g_return_val_if_fail (context->state != STATE_ERROR, FALSE);
if ((context->flags & XMP_FLAG_FIND_XPACKET)
&& (context->state == STATE_START
|| context->state == STATE_AFTER_XPACKET))
{
/* There may be some arbitrary data before the <?xpacket...?>
* marker so we should first find it according to the
* recommendations of the XMP specification. Once the start of
* the XMP packet has been found, the GMarkupParser can start
* its work on the text (including the <?xpacket...?> marker).
*/
/* FIXME: wrong, wrong, wrong! but useful for simple tests... */
gint i, e;
for (i = 0; i < text_len - 20; i++)
if (! strncmp (text + i, "<?xpacket begin=", 16))
{
for (e = i; e < text_len - 10; e++)
if (! strncmp (text + e, "<?xpacket end=", 14))
break;
while ((e < text_len) && *(text + e) != '>')
e++;
return g_markup_parse_context_parse (context->markup_context,
text + i, e - i + 1, error);
}
parse_error (context, error, XMP_ERROR_NO_XPACKET, NULL);
return FALSE;
}
return g_markup_parse_context_parse (context->markup_context,
text, text_len, error);
}
/**
* xmp_parse_context_end_parse:
* @context: a #XMPParseContext
* @error: return location for a #GError
*
* Signals to the #XMPParseContext that all data has been fed into the
* parse context with xmp_parse_context_parse(). This function
* reports an error if the document did not contain any XMP packet or
* if the document isn't complete, for example if elements are still
* open.
*
* Return value: %TRUE on success, %FALSE if an error was set
**/
gboolean
xmp_parse_context_end_parse (XMPParseContext *context,
GError **error)
{
g_return_val_if_fail (context != NULL, FALSE);
g_return_val_if_fail (context->state != STATE_ERROR, FALSE);
if (context->state == STATE_START)
parse_error (context, error, XMP_ERROR_NO_XPACKET, NULL);
return g_markup_parse_context_end_parse (context->markup_context, error);
}
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