gdb/xml-support.h

   1 /* Helper routines for parsing XML using Expat.
   2
   3    Copyright (C) 2006-2017 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 3 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, see <http://www.gnu.org/licenses/>.  */
  19
  20
  21 #ifndef XML_SUPPORT_H
  22 #define XML_SUPPORT_H
  23
  24 #include "gdb_obstack.h"
  25 #include "vec.h"
  26 #include "xml-utils.h"
  27
  28 struct gdb_xml_parser;
  29 struct gdb_xml_element;
  30 struct gdb_xml_attribute;
  31
  32 /* Return an XML document which was compiled into GDB, from
  33    the given FILENAME, or NULL if the file was not compiled in.  */
  34
  35 const char *fetch_xml_builtin (const char *filename);
  36
  37 /* A to_xfer_partial helper function which reads XML files which were
  38    compiled into GDB.  The target may call this function from its own
  39    to_xfer_partial handler, after converting object and annex to the
  40    appropriate filename.  */
  41
  42 LONGEST xml_builtin_xfer_partial (const char *filename,
  43                                   gdb_byte *readbuf, const gdb_byte *writebuf,
  44                                   ULONGEST offset, LONGEST len);
  45
  46 /* The text of compiled-in XML documents, from xml-builtin.c
  47    (generated).  */
  48
  49 extern const char *xml_builtin[][2];
  50
  51 /* Support for XInclude.  */
  52
  53 /* Callback to fetch a new XML file, based on the provided HREF.  */
  54
  55 typedef gdb::unique_xmalloc_ptr<char> (*xml_fetch_another) (const char *href,
  56                                                             void *baton);
  57
  58 /* Append the expansion of TEXT after processing <xi:include> tags in
  59    RESULT.  FETCHER will be called (with FETCHER_BATON) to retrieve
  60    any new files.  DEPTH should be zero on the initial call.
  61
  62    On failure, this function uses NAME in a warning and returns false.
  63    It may throw an exception, but does not for XML parsing
  64    problems.  */
  65
  66 bool xml_process_xincludes (std::string &result,
  67                             const char *name, const char *text,
  68                             xml_fetch_another fetcher, void *fetcher_baton,
  69                             int depth);
  70
  71 /* Simplified XML parser infrastructure.  */
  72
  73 /* A name and value pair, used to record parsed attributes.  */
  74
  75 struct gdb_xml_value
  76 {
  77   const char *name;
  78   void *value;
  79 };
  80 typedef struct gdb_xml_value gdb_xml_value_s;
  81 DEF_VEC_O(gdb_xml_value_s);
  82
  83 /* The type of an attribute handler.
  84
  85    PARSER is the current XML parser, which should be used to issue any
  86    debugging or error messages.  The second argument is the
  87    corresponding attribute description, so that a single handler can
  88    be used for multiple attributes; the attribute name is available
  89    for error messages and the handler data is available for additional
  90    customization (see gdb_xml_parse_attr_enum).  VALUE is the string
  91    value of the attribute.
  92
  93    The returned value should be freeable with xfree, and will be freed
  94    after the start handler is called.  Errors should be reported by
  95    calling gdb_xml_error.  */
  96
  97 typedef void *(gdb_xml_attribute_handler) (struct gdb_xml_parser *parser,
  98                                            const struct gdb_xml_attribute *,
  99                                            const char *value);
 100
 101 /* Flags for attributes.  If no flags are specified, the attribute is
 102    required.  */
 103
 104 enum gdb_xml_attribute_flag
 105 {
 106   GDB_XML_AF_NONE,
 107   GDB_XML_AF_OPTIONAL = 1 << 0,  /* The attribute is optional.  */
 108 };
 109
 110 /* An expected attribute and the handler to call when it is
 111    encountered.  Arrays of struct gdb_xml_attribute are terminated
 112    by an entry with NAME == NULL.  */
 113
 114 struct gdb_xml_attribute
 115 {
 116   const char *name;
 117   int flags;
 118   gdb_xml_attribute_handler *handler;
 119   const void *handler_data;
 120 };
 121
 122 /* Flags for elements.  If no flags are specified, the element is
 123    required exactly once.  */
 124
 125 enum gdb_xml_element_flag
 126 {
 127   GDB_XML_EF_NONE,
 128   GDB_XML_EF_OPTIONAL = 1 << 0,  /* The element is optional.  */
 129   GDB_XML_EF_REPEATABLE = 1 << 1,  /* The element is repeatable.  */
 130 };
 131
 132 /* A handler called at the beginning of an element.
 133
 134    PARSER is the current XML parser, which should be used to issue any
 135    debugging or error messages.  ELEMENT is the current element.
 136    USER_DATA is the opaque pointer supplied when the parser was
 137    created.  ATTRIBUTES is a vector of the values of any attributes
 138    attached to this element.
 139
 140    The start handler will only be called if all the required
 141    attributes were present and parsed successfully, and elements of
 142    ATTRIBUTES are guaranteed to be in the same order used in
 143    ELEMENT->ATTRIBUTES (not the order from the XML file).  Accordingly
 144    fixed offsets can be used to find any non-optional attributes as
 145    long as no optional attributes precede them.  */
 146
 147 typedef void (gdb_xml_element_start_handler)
 148      (struct gdb_xml_parser *parser, const struct gdb_xml_element *element,
 149       void *user_data, VEC(gdb_xml_value_s) *attributes);
 150
 151 /* A handler called at the end of an element.
 152
 153    PARSER, ELEMENT, and USER_DATA are as for the start handler.  BODY
 154    is any accumulated body text inside the element, with leading and
 155    trailing whitespace removed.  It will never be NULL.  */
 156
 157 typedef void (gdb_xml_element_end_handler)
 158      (struct gdb_xml_parser *, const struct gdb_xml_element *,
 159       void *user_data, const char *body_text);
 160
 161 /* An expected element and the handlers to call when it is
 162    encountered.  Arrays of struct gdb_xml_element are terminated
 163    by an entry with NAME == NULL.  */
 164
 165 struct gdb_xml_element
 166 {
 167   const char *name;
 168   const struct gdb_xml_attribute *attributes;
 169   const struct gdb_xml_element *children;
 170   int flags;
 171
 172   gdb_xml_element_start_handler *start_handler;
 173   gdb_xml_element_end_handler *end_handler;
 174 };
 175
 176 /* Parse a XML document.  DOCUMENT is the data to parse, which should
 177    be NUL-terminated. If non-NULL, use the compiled-in DTD named
 178    DTD_NAME to drive the parsing.
 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_quick (const char *name, const char *dtd_name,
 185                          const struct gdb_xml_element *elements,
 186                          const char *document, void *user_data);
 187
 188 /* Issue a debugging message from one of PARSER's handlers.  */
 189
 190 void gdb_xml_debug (struct gdb_xml_parser *parser, const char *format, ...)
 191   ATTRIBUTE_PRINTF (2, 3);
 192
 193 /* Issue an error message from one of PARSER's handlers, and stop
 194    parsing.  */
 195
 196 void gdb_xml_error (struct gdb_xml_parser *parser, const char *format, ...)
 197   ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 3);
 198
 199 /* Find the attribute named NAME in the set of parsed attributes
 200    ATTRIBUTES.  Returns NULL if not found.  */
 201
 202 struct gdb_xml_value *xml_find_attribute (VEC(gdb_xml_value_s) *attributes,
 203                                           const char *name);
 204
 205 /* Parse an integer attribute into a ULONGEST.  */
 206
 207 extern gdb_xml_attribute_handler gdb_xml_parse_attr_ulongest;
 208
 209 /* Map NAME to VALUE.  A struct gdb_xml_enum * should be saved as the
 210    value of handler_data when using gdb_xml_parse_attr_enum to parse a
 211    fixed list of possible strings.  The list is terminated by an entry
 212    with NAME == NULL.  */
 213
 214 struct gdb_xml_enum
 215 {
 216   const char *name;
 217   ULONGEST value;
 218 };
 219
 220 /* A handler_data for yes/no boolean values.  */
 221 extern const struct gdb_xml_enum gdb_xml_enums_boolean[];
 222
 223 extern gdb_xml_attribute_handler gdb_xml_parse_attr_enum;
 224
 225 /* Parse an integer string into a ULONGEST and return it, or call
 226    gdb_xml_error if it could not be parsed.  */
 227
 228 ULONGEST gdb_xml_parse_ulongest (struct gdb_xml_parser *parser,
 229                                  const char *value);
 230
 231 /* Open FILENAME, read all its text into memory, close it, and return
 232    the text.  If something goes wrong, return NULL and warn.  */
 233
 234 extern gdb::unique_xmalloc_ptr<char> xml_fetch_content_from_file
 235     (const char *filename, void *baton);
 236
 237 #endif