gdb/xml-support.h

   1 /* Helper routines for parsing XML using Expat.
   2
   3    Copyright (C) 2006, 2007 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 51 Franklin Street, Fifth Floor,
  20    Boston, MA 02110-1301, USA.  */
  21
  22
  23 #ifndef XML_SUPPORT_H
  24 #define XML_SUPPORT_H
  25
  26 #include "gdb_obstack.h"
  27 #include "vec.h"
  28
  29 struct gdb_xml_parser;
  30 struct gdb_xml_element;
  31 struct gdb_xml_attribute;
  32
  33 /* Support for XInclude.  */
  34
  35 /* Callback to fetch a new XML file, based on the provided HREF.  */
  36
  37 typedef char *(*xml_fetch_another) (const char *href, void *baton);
  38
  39 /* Return a new string which is the expansion of TEXT after processing
  40    <xi:include> tags.  FETCHER will be called (with FETCHER_BATON) to
  41    retrieve any new files.  DEPTH should be zero on the initial call.
  42
  43    On failure, this function uses NAME in a warning and returns NULL.
  44    It may throw an exception, but does not for XML parsing
  45    problems.  */
  46
  47 char *xml_process_xincludes (const char *name, const char *text,
  48                              xml_fetch_another fetcher, void *fetcher_baton,
  49                              int depth);
  50
  51 /* Return an XML document which was compiled into GDB, from
  52    the given FILENAME, or NULL if the file was not compiled in.  */
  53
  54 const char *fetch_xml_builtin (const char *filename);
  55
  56 /* The text of compiled-in XML documents, from xml-builtin.c
  57    (generated).  */
  58 extern const char *xml_builtin[][2];
  59
  60 /* Simplified XML parser infrastructure.  */
  61
  62 /* A name and value pair, used to record parsed attributes.  */
  63
  64 struct gdb_xml_value
  65 {
  66   const char *name;
  67   void *value;
  68 };
  69 typedef struct gdb_xml_value gdb_xml_value_s;
  70 DEF_VEC_O(gdb_xml_value_s);
  71
  72 /* The type of an attribute handler.
  73
  74    PARSER is the current XML parser, which should be used to issue any
  75    debugging or error messages.  The second argument is the
  76    corresponding attribute description, so that a single handler can
  77    be used for multiple attributes; the attribute name is available
  78    for error messages and the handler data is available for additional
  79    customization (see gdb_xml_parse_attr_enum).  VALUE is the string
  80    value of the attribute.
  81
  82    The returned value should be freeable with xfree, and will be freed
  83    after the start handler is called.  Errors should be reported by
  84    calling gdb_xml_error.  */
  85
  86 typedef void *(gdb_xml_attribute_handler) (struct gdb_xml_parser *parser,
  87                                            const struct gdb_xml_attribute *,
  88                                            const char *value);
  89
  90 /* Flags for attributes.  If no flags are specified, the attribute is
  91    required.  */
  92
  93 enum gdb_xml_attribute_flag
  94 {
  95   GDB_XML_AF_NONE,
  96   GDB_XML_AF_OPTIONAL = 1 << 0,  /* The attribute is optional.  */
  97 };
  98
  99 /* An expected attribute and the handler to call when it is
 100    encountered.  Arrays of struct gdb_xml_attribute are terminated
 101    by an entry with NAME == NULL.  */
 102
 103 struct gdb_xml_attribute
 104 {
 105   const char *name;
 106   int flags;
 107   gdb_xml_attribute_handler *handler;
 108   const void *handler_data;
 109 };
 110
 111 /* Flags for elements.  If no flags are specified, the element is
 112    required exactly once.  */
 113
 114 enum gdb_xml_element_flag
 115 {
 116   GDB_XML_EF_NONE,
 117   GDB_XML_EF_OPTIONAL = 1 << 0,  /* The element is optional.  */
 118   GDB_XML_EF_REPEATABLE = 1 << 1,  /* The element is repeatable.  */
 119 };
 120
 121 /* A handler called at the beginning of an element.
 122
 123    PARSER is the current XML parser, which should be used to issue any
 124    debugging or error messages.  ELEMENT is the current element.
 125    USER_DATA is the opaque pointer supplied when the parser was
 126    created.  ATTRIBUTES is a vector of the values of any attributes
 127    attached to this element.
 128
 129    The start handler will only be called if all the required
 130    attributes were present and parsed successfully, and elements of
 131    ATTRIBUTES are guaranteed to be in the same order used in
 132    ELEMENT->ATTRIBUTES (not the order from the XML file).  Accordingly
 133    fixed offsets can be used to find any non-optional attributes as
 134    long as no optional attributes precede them.  */
 135
 136 typedef void (gdb_xml_element_start_handler)
 137      (struct gdb_xml_parser *parser, const struct gdb_xml_element *element,
 138       void *user_data, VEC(gdb_xml_value_s) *attributes);
 139
 140 /* A handler called at the end of an element.
 141
 142    PARSER, ELEMENT, and USER_DATA are as for the start handler.  BODY
 143    is any accumulated body text inside the element, with leading and
 144    trailing whitespace removed.  It will never be NULL.  */
 145
 146 typedef void (gdb_xml_element_end_handler)
 147      (struct gdb_xml_parser *, const struct gdb_xml_element *,
 148       void *user_data, const char *body_text);
 149
 150 /* An expected element and the handlers to call when it is
 151    encountered.  Arrays of struct gdb_xml_element are terminated
 152    by an entry with NAME == NULL.  */
 153
 154 struct gdb_xml_element
 155 {
 156   const char *name;
 157   const struct gdb_xml_attribute *attributes;
 158   const struct gdb_xml_element *children;
 159   int flags;
 160
 161   gdb_xml_element_start_handler *start_handler;
 162   gdb_xml_element_end_handler *end_handler;
 163 };
 164
 165 /* Initialize and return a parser.  Register a cleanup to destroy the
 166    parser.  */
 167
 168 struct gdb_xml_parser *gdb_xml_create_parser_and_cleanup
 169   (const char *name, const struct gdb_xml_element *elements,
 170    void *user_data);
 171
 172 /* Associate DTD_NAME, which must be the name of a compiled-in DTD,
 173    with PARSER.  */
 174
 175 void gdb_xml_use_dtd (struct gdb_xml_parser *parser, const char *dtd_name);
 176
 177 /* Invoke PARSER on BUFFER.  BUFFER is the data to parse, which
 178    should be NUL-terminated.
 179
 180    The return value is 0 for success or -1 for error.  It may throw,
 181    but only if something unexpected goes wrong during parsing; parse
 182    errors will be caught, warned about, and reported as failure.  */
 183
 184 int gdb_xml_parse (struct gdb_xml_parser *parser, const char *buffer);
 185
 186 /* Issue a debugging message from one of PARSER's handlers.  */
 187
 188 void gdb_xml_debug (struct gdb_xml_parser *parser, const char *format, ...)
 189      ATTR_FORMAT (printf, 2, 0);
 190
 191 /* Issue an error message from one of PARSER's handlers, and stop
 192    parsing.  */
 193
 194 void gdb_xml_error (struct gdb_xml_parser *parser, const char *format, ...)
 195      ATTR_NORETURN ATTR_FORMAT (printf, 2, 0);
 196
 197 /* Parse an integer attribute into a ULONGEST.  */
 198
 199 extern gdb_xml_attribute_handler gdb_xml_parse_attr_ulongest;
 200
 201 /* Map NAME to VALUE.  A struct gdb_xml_enum * should be saved as the
 202    value of handler_data when using gdb_xml_parse_attr_enum to parse a
 203    fixed list of possible strings.  The list is terminated by an entry
 204    with NAME == NULL.  */
 205
 206 struct gdb_xml_enum
 207 {
 208   const char *name;
 209   ULONGEST value;
 210 };
 211
 212 extern gdb_xml_attribute_handler gdb_xml_parse_attr_enum;
 213
 214 /* Parse an integer string into a ULONGEST and return it, or call
 215    gdb_xml_error if it could not be parsed.  */
 216
 217 ULONGEST gdb_xml_parse_ulongest (struct gdb_xml_parser *parser,
 218                                  const char *value);
 219
 220 #endif