gdb/xml-support.c

   1 /* Helper routines for parsing XML using Expat.
   2
   3    Copyright (C) 2006
   4    Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 51 Franklin Street, Fifth Floor,
  21    Boston, MA 02110-1301, USA.  */
  22
  23 #include "defs.h"
  24
  25 /* The contents of this file are only useful if XML support is
  26    available.  */
  27 #ifdef HAVE_LIBEXPAT
  28
  29 #include "exceptions.h"
  30 #include "xml-support.h"
  31
  32 #include <expat.h>
  33
  34 #include "gdb_string.h"
  35
  36 /* Returns the value of attribute ATTR from expat attribute list
  37    ATTRLIST.  If not found, throws an exception.  */
  38
  39 const XML_Char *
  40 xml_get_required_attribute (const XML_Char **attrs,
  41                             const XML_Char *attr)
  42 {
  43   const XML_Char **p;
  44   for (p = attrs; *p; p += 2)
  45     {
  46       const char *name = p[0];
  47       const char *val = p[1];
  48
  49       if (strcmp (name, attr) == 0)
  50         return val;
  51     }
  52   throw_error (XML_PARSE_ERROR, _("Can't find attribute %s"), attr);
  53 }
  54
  55 /* Parse a field VALSTR that we expect to contain an integer value.
  56    The integer is returned in *VALP.  The string is parsed with an
  57    equivalent to strtoul.
  58
  59    Returns 0 for success, -1 for error.  */
  60
  61 static int
  62 xml_parse_unsigned_integer (const char *valstr, ULONGEST *valp)
  63 {
  64   const char *endptr;
  65   ULONGEST result;
  66
  67   if (*valstr == '\0')
  68     return -1;
  69
  70   result = strtoulst (valstr, &endptr, 0);
  71   if (*endptr != '\0')
  72     return -1;
  73
  74   *valp = result;
  75   return 0;
  76 }
  77
  78 /* Gets the value of an integer attribute named ATTR, if it's present.
  79    If the attribute is not found, or can't be parsed as integer,
  80    throws an exception.  */
  81
  82 ULONGEST
  83 xml_get_integer_attribute (const XML_Char **attrs,
  84                            const XML_Char *attr)
  85 {
  86   ULONGEST result;
  87   const XML_Char *value = xml_get_required_attribute (attrs, attr);
  88
  89   if (xml_parse_unsigned_integer (value, &result) != 0)
  90     {
  91       throw_error (XML_PARSE_ERROR,
  92                    _("Can't convert value of attribute %s, %s, to integer"),
  93                    attr, value);
  94     }
  95   return result;
  96 }
  97
  98 /* Obtains a value of attribute with enumerated type. In XML, enumerated
  99    attributes have string as a value, and in C, they are represented as
 100    values of enumerated type. This function maps the attribute onto
 101    an integer value that can be immediately converted into enumerated
 102    type.
 103
 104    First, obtains the string value of ATTR in ATTRS.
 105    Then, finds the index of that value in XML_NAMES, which is a zero-terminated
 106    array of strings. If found, returns the element of VALUES with that index.
 107    Otherwise throws.  */
 108
 109 int
 110 xml_get_enum_value (const XML_Char **attrs,
 111                     const XML_Char *attr,
 112                     const XML_Char **xml_names,
 113                     int *values)
 114 {
 115   const XML_Char *value = xml_get_required_attribute (attrs, attr);
 116
 117   int i;
 118   for (i = 0; xml_names[i]; ++i)
 119     {
 120       if (strcmp (xml_names[i], value) == 0)
 121         return values[i];
 122     }
 123   throw_error (XML_PARSE_ERROR,
 124                _("Invalid enumerated value in XML: %s"), value);
 125 }
 126
 127 /* Cleanup wrapper for XML_ParserFree, with the correct type
 128    for make_cleanup.  */
 129
 130 static void
 131 free_xml_parser (void *parser)
 132 {
 133   XML_ParserFree (parser);
 134 }
 135
 136 /* Register a cleanup to release PARSER.  Only the parser itself
 137    is freed; another cleanup may be necessary to discard any
 138    associated user data.  */
 139
 140 void
 141 make_cleanup_free_xml_parser (XML_Parser parser)
 142 {
 143   make_cleanup (free_xml_parser, parser);
 144 }
 145
 146 #endif /* HAVE_LIBEXPAT */