1/*
2   neon XML parser interface
3   Copyright (C) 1999-2007, Joe Orton <joe@manyfish.co.uk>
4
5   This library is free software; you can redistribute it and/or
6   modify it under the terms of the GNU Library General Public
7   License as published by the Free Software Foundation; either
8   version 2 of the License, or (at your option) any later version.
9
10   This library is distributed in the hope that it will be useful,
11   but WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13   Library General Public License for more details.
14
15   You should have received a copy of the GNU Library General Public
16   License along with this library; if not, write to the Free
17   Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
18   MA 02111-1307, USA
19
20*/
21
22#ifndef NE_XML_H
23#define NE_XML_H
24
25#include <sys/types.h> /* for size_t */
26
27#include "ne_defs.h"
28
29NE_BEGIN_DECLS
30
31/* The neon XML interface filters a streamed XML tree through a stack
32 * of SAX "handlers".  A handler is made up of three callbacks
33 * (start-element, char-data, end-element).  Each start-element event
34 * is passed to each handler in the stack in turn until one until one
35 * accepts the element.  This handler then receives subsequent
36 * char-data and end-element events for the element.
37 *
38 * For each new start-element event, the search up the handler stack
39 * begins with the handler for the parent element (for the root
40 * element, at the base of the stack).
41 *
42 * For each accepted element, a "state" integer is stored, which is
43 * passed to the corresponding char-data and end-element callbacks for
44 * the element.  This integer is also passed to the start-element
45 * callback of child elements so they can determine context.
46 *
47 * If no handler in the stack accepts a particular element, it (and
48 * its children, if any) is ignored. */
49
50#define NE_XML_DECLINE (0)
51#define NE_XML_ABORT (-1)
52
53/* A start-element callback for element with given namespace/name.
54 * The callback may return:
55 *   <0  =>  abort the parse (NE_XML_ABORT)
56 *    0  =>  decline this element (NE_XML_DECLINE)
57 *   >0  =>  accept this element; value is state for this element.
58 *
59 * The 'parent' integer is the state returned by the handler of the
60 * parent element.   The attributes array gives name/value pairs
61 * in atts[n] and atts[n+1] from n=0 up to atts[n]==NULL. */
62typedef int ne_xml_startelm_cb(void *userdata, int parent,
63                               const char *nspace, const char *name,
64                               const char **atts);
65
66/* state for the root element */
67#define NE_XML_STATEROOT (0)
68
69/* Character data callback; may return non-zero to abort the parse. */
70typedef int ne_xml_cdata_cb(void *userdata, int state,
71                            const char *cdata, size_t len);
72/* End element callback; may return non-zero to abort the parse. */
73typedef int ne_xml_endelm_cb(void *userdata, int state,
74                             const char *nspace, const char *name);
75
76typedef struct ne_xml_parser_s ne_xml_parser;
77
78/* Create an XML parser. */
79ne_xml_parser *ne_xml_create(void);
80
81/* Push a new handler on the stack of parser 'p'. 'cdata' and/or
82 * 'endelm' may be NULL; startelm must be non-NULL. */
83void ne_xml_push_handler(ne_xml_parser *p,
84                         ne_xml_startelm_cb *startelm,
85                         ne_xml_cdata_cb *cdata,
86                         ne_xml_endelm_cb *endelm,
87                         void *userdata);
88
89/* ne_xml_failed returns non-zero if there was an error during
90 * parsing, or zero if the parse completed successfully.  The return
91 * value is equal to that of the last ne_xml_parse() call for this
92 * parser object. */
93int ne_xml_failed(ne_xml_parser *p);
94
95/* Set error string for parser.  (The string may be truncated
96 * internally). */
97void ne_xml_set_error(ne_xml_parser *p, const char *msg);
98
99/* Return the error string (and never NULL).  After ne_xml_failed
100 * returns >0, this will describe the parse error.  Otherwise it will
101 * be a default error string. */
102const char *ne_xml_get_error(ne_xml_parser *p);
103
104/* Parse the given block of input of length len.  Parser must be
105 * called with len=0 to signify the end of the document (for that
106 * case, the block argument is ignored).  Returns zero on success, or
107 * non-zero on error: for an XML syntax error, a positive number is
108 * returned; if parsing is aborted by a caller-supplied callback, that
109 * callback's return value is returned. */
110int ne_xml_parse(ne_xml_parser *p, const char *block, size_t len);
111
112/* As ne_xml_parse, casting (ne_xml_parser *)userdata internally.
113 * (This function can be passed to ne_add_response_body_reader) */
114int ne_xml_parse_v(void *userdata, const char *block, size_t len);
115
116/* Return current line of document during parsing or after parsing is
117 * complete. */
118int ne_xml_currentline(ne_xml_parser *p);
119
120/* From a start_element callback which was passed 'attrs' using given
121 * parser, return attribute of given name and namespace.  If nspace is
122 * NULL, no namespace resolution is performed.  Note that this call is
123 * context-specific; if called outside a start_element callback,
124 * behaviour is undefined. */
125const char *ne_xml_get_attr(ne_xml_parser *parser,
126			    const char **attrs, const char *nspace,
127			    const char *name);
128
129/* From a start_element callback, resolve a given XML Namespace
130 * prefix, if defined.  Given a non-NULL prefix, returns the namespace
131 * URI which corresponds to the prefix 'prefix' (of length 'length'),
132 * or NULL if no such namespace prefix is defined.  Given a NULL
133 * prefix, returns the default namespace URI or the empty string if
134 * none is defined.  Note that this call is context-specific; if
135 * called outside a start_element callback, behaviour is undefined. */
136const char *ne_xml_resolve_nspace(ne_xml_parser *parser,
137                                  const char *prefix, size_t length);
138
139/* Return the encoding of the document being parsed.  May return NULL
140 * if no encoding is defined or if the XML declaration has not yet
141 * been parsed. */
142const char *ne_xml_doc_encoding(const ne_xml_parser *p);
143
144/* Destroy the parser object. */
145void ne_xml_destroy(ne_xml_parser *p);
146
147/* A utility interface for mapping {nspace, name} onto an integer. */
148struct ne_xml_idmap {
149    const char *nspace, *name;
150    int id;
151};
152
153/* Return the size of an idmap array */
154#define NE_XML_MAPLEN(map) (sizeof(map) / sizeof(struct ne_xml_idmap))
155
156/* Return the 'id' corresponding to {nspace, name}, or zero. */
157int ne_xml_mapid(const struct ne_xml_idmap map[], size_t maplen,
158                 const char *nspace, const char *name);
159
160/* media type, appropriate for adding to a Content-Type header */
161#define NE_XML_MEDIA_TYPE "application/xml"
162
163NE_END_DECLS
164
165#endif /* NE_XML_H */
166