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 char *(*xml_fetch_another) (const char *href, void *baton);
  56
  57 /* Append the expansion of TEXT after processing <xi:include> tags in
  58    RESULT.  FETCHER will be called (with FETCHER_BATON) to retrieve
  59    any new files.  DEPTH should be zero on the initial call.
  60
  61    On failure, this function uses NAME in a warning and returns false.
  62    It may throw an exception, but does not for XML parsing
  63    problems.  */
  64
  65 bool xml_process_xincludes (std::string &result,
  66                             const char *name, const char *text,
  67                             xml_fetch_another fetcher, void *fetcher_baton,
  68                             int depth);
  69
  70 /* Simplified XML parser infrastructure.  */
  71
  72 /* A name and value pair, used to record parsed attributes.  */
  73
  74 struct gdb_xml_value
  75 {
  76   const char *name;
  77   void *value;
  78 };
  79 typedef struct gdb_xml_value gdb_xml_value_s;
  80 DEF_VEC_O(gdb_xml_value_s);
  81
  82 /* The type of an attribute handler.
  83
  84    PARSER is the current XML parser, which should be used to issue any
  85    debugging or error messages.  The second argument is the
  86    corresponding attribute description, so that a single handler can
  87    be used for multiple attributes; the attribute name is available
  88    for error messages and the handler data is available for additional
  89    customization (see gdb_xml_parse_attr_enum).  VALUE is the string
  90    value of the attribute.
  91
  92    The returned value should be freeable with xfree, and will be freed
  93    after the start handler is called.  Errors should be reported by
  94    calling gdb_xml_error.  */
  95
  96 typedef void *(gdb_xml_attribute_handler) (struct gdb_xml_parser *parser,
  97                                            const struct gdb_xml_attribute *,
  98                                            const char *value);
  99
 100 /* Flags for attributes.  If no flags are specified, the attribute is
 101    required.  */
 102
 103 enum gdb_xml_attribute_flag
 104 {
 105   GDB_XML_AF_NONE,
 106   GDB_XML_AF_OPTIONAL = 1 << 0,  /* The attribute is optional.  */
 107 };
 108
 109 /* An expected attribute and the handler to call when it is
 110    encountered.  Arrays of struct gdb_xml_attribute are terminated
 111    by an entry with NAME == NULL.  */
 112
 113 struct gdb_xml_attribute
 114 {
 115   const char *name;
 116   int flags;
 117   gdb_xml_attribute_handler *handler;
 118   const void *handler_data;
 119 };
 120
 121 /* Flags for elements.  If no flags are specified, the element is
 122    required exactly once.  */
 123
 124 enum gdb_xml_element_flag
 125 {
 126   GDB_XML_EF_NONE,
 127   GDB_XML_EF_OPTIONAL = 1 << 0,  /* The element is optional.  */
 128   GDB_XML_EF_REPEATABLE = 1 << 1,  /* The element is repeatable.  */
 129 };
 130
 131 /* A handler called at the beginning of an element.
 132
 133    PARSER is the current XML parser, which should be used to issue any
 134    debugging or error messages.  ELEMENT is the current element.
 135    USER_DATA is the opaque pointer supplied when the parser was
 136    created.  ATTRIBUTES is a vector of the values of any attributes
 137    attached to this element.
 138
 139    The start handler will only be called if all the required
 140    attributes were present and parsed successfully, and elements of
 141    ATTRIBUTES are guaranteed to be in the same order used in
 142    ELEMENT->ATTRIBUTES (not the order from the XML file).  Accordingly
 143    fixed offsets can be used to find any non-optional attributes as
 144    long as no optional attributes precede them.  */
 145
 146 typedef void (gdb_xml_element_start_handler)
 147      (struct gdb_xml_parser *parser, const struct gdb_xml_element *element,
 148       void *user_data, VEC(gdb_xml_value_s) *attributes);
 149
 150 /* A handler called at the end of an element.
 151
 152    PARSER, ELEMENT, and USER_DATA are as for the start handler.  BODY
 153    is any accumulated body text inside the element, with leading and
 154    trailing whitespace removed.  It will never be NULL.  */
 155
 156 typedef void (gdb_xml_element_end_handler)
 157      (struct gdb_xml_parser *, const struct gdb_xml_element *,
 158       void *user_data, const char *body_text);
 159
 160 /* An expected element and the handlers to call when it is
 161    encountered.  Arrays of struct gdb_xml_element are terminated
 162    by an entry with NAME == NULL.  */
 163
 164 struct gdb_xml_element
 165 {
 166   const char *name;
 167   const struct gdb_xml_attribute *attributes;
 168   const struct gdb_xml_element *children;
 169   int flags;
 170
 171   gdb_xml_element_start_handler *start_handler;
 172   gdb_xml_element_end_handler *end_handler;
 173 };
 174
 175 /* Parse a XML document.  DOCUMENT is the data to parse, which should
 176    be NUL-terminated. If non-NULL, use the compiled-in DTD named
 177    DTD_NAME to drive the parsing.
 178
 179    The return value is 0 for success or -1 for error.  It may throw,
 180    but only if something unexpected goes wrong during parsing; parse
 181    errors will be caught, warned about, and reported as failure.  */
 182
 183 int gdb_xml_parse_quick (const char *name, const char *dtd_name,
 184                          const struct gdb_xml_element *elements,
 185                          const char *document, void *user_data);
 186
 187 /* Issue a debugging message from one of PARSER's handlers.  */
 188
 189 void gdb_xml_debug (struct gdb_xml_parser *parser, const char *format, ...)
 190   ATTRIBUTE_PRINTF (2, 3);
 191
 192 /* Issue an error message from one of PARSER's handlers, and stop
 193    parsing.  */
 194
 195 void gdb_xml_error (struct gdb_xml_parser *parser, const char *format, ...)
 196   ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 3);
 197
 198 /* Find the attribute named NAME in the set of parsed attributes
 199    ATTRIBUTES.  Returns NULL if not found.  */
 200
 201 struct gdb_xml_value *xml_find_attribute (VEC(gdb_xml_value_s) *attributes,
 202                                           const char *name);
 203
 204 /* Parse an integer attribute into a ULONGEST.  */
 205
 206 extern gdb_xml_attribute_handler gdb_xml_parse_attr_ulongest;
 207
 208 /* Map NAME to VALUE.  A struct gdb_xml_enum * should be saved as the
 209    value of handler_data when using gdb_xml_parse_attr_enum to parse a
 210    fixed list of possible strings.  The list is terminated by an entry
 211    with NAME == NULL.  */
 212
 213 struct gdb_xml_enum
 214 {
 215   const char *name;
 216   ULONGEST value;
 217 };
 218
 219 /* A handler_data for yes/no boolean values.  */
 220 extern const struct gdb_xml_enum gdb_xml_enums_boolean[];
 221
 222 extern gdb_xml_attribute_handler gdb_xml_parse_attr_enum;
 223
 224 /* Parse an integer string into a ULONGEST and return it, or call
 225    gdb_xml_error if it could not be parsed.  */
 226
 227 ULONGEST gdb_xml_parse_ulongest (struct gdb_xml_parser *parser,
 228                                  const char *value);
 229
 230 /* Open FILENAME, read all its text into memory, close it, and return
 231    the text.  If something goes wrong, return NULL and warn.  */
 232
 233 extern char *xml_fetch_content_from_file (const char *filename,
 234                                           void *baton);
 235
 236 #endif