1 /* Helper routines for parsing XML using Expat. 2 3 Copyright (C) 2006-2020 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 "gdbsupport/xml-utils.h" 26 #include "gdbsupport/byte-vector.h" 27 #include "gdbsupport/gdb_optional.h" 28 29 struct gdb_xml_parser; 30 struct gdb_xml_element; 31 struct gdb_xml_attribute; 32 33 /* Return an XML document which was compiled into GDB, from 34 the given FILENAME, or NULL if the file was not compiled in. */ 35 36 const char *fetch_xml_builtin (const char *filename); 37 38 /* A to_xfer_partial helper function which reads XML files which were 39 compiled into GDB. The target may call this function from its own 40 to_xfer_partial handler, after converting object and annex to the 41 appropriate filename. */ 42 43 LONGEST xml_builtin_xfer_partial (const char *filename, 44 gdb_byte *readbuf, const gdb_byte *writebuf, 45 ULONGEST offset, LONGEST len); 46 47 /* Support for XInclude. */ 48 49 /* Callback to fetch a new XML file, based on the provided HREF. */ 50 51 typedef gdb::optional<gdb::char_vector> (*xml_fetch_another) (const char *href, 52 void *baton); 53 54 /* Append the expansion of TEXT after processing <xi:include> tags in 55 RESULT. FETCHER will be called (with FETCHER_BATON) to retrieve 56 any new files. DEPTH should be zero on the initial call. 57 58 On failure, this function uses NAME in a warning and returns false. 59 It may throw an exception, but does not for XML parsing 60 problems. */ 61 62 bool xml_process_xincludes (std::string &result, 63 const char *name, const char *text, 64 xml_fetch_another fetcher, void *fetcher_baton, 65 int depth); 66 67 /* Simplified XML parser infrastructure. */ 68 69 /* A name and value pair, used to record parsed attributes. */ 70 71 struct gdb_xml_value 72 { 73 gdb_xml_value (const char *name_, void *value_) 74 : name (name_), value (value_) 75 {} 76 77 const char *name; 78 gdb::unique_xmalloc_ptr<void> value; 79 }; 80 81 /* The type of an attribute handler. 82 83 PARSER is the current XML parser, which should be used to issue any 84 debugging or error messages. The second argument is the 85 corresponding attribute description, so that a single handler can 86 be used for multiple attributes; the attribute name is available 87 for error messages and the handler data is available for additional 88 customization (see gdb_xml_parse_attr_enum). VALUE is the string 89 value of the attribute. 90 91 The returned value should be freeable with xfree, and will be freed 92 after the start handler is called. Errors should be reported by 93 calling gdb_xml_error. */ 94 95 typedef void *(gdb_xml_attribute_handler) (struct gdb_xml_parser *parser, 96 const struct gdb_xml_attribute *, 97 const char *value); 98 99 /* Flags for attributes. If no flags are specified, the attribute is 100 required. */ 101 102 enum gdb_xml_attribute_flag 103 { 104 GDB_XML_AF_NONE, 105 GDB_XML_AF_OPTIONAL = 1 << 0, /* The attribute is optional. */ 106 }; 107 108 /* An expected attribute and the handler to call when it is 109 encountered. Arrays of struct gdb_xml_attribute are terminated 110 by an entry with NAME == NULL. */ 111 112 struct gdb_xml_attribute 113 { 114 const char *name; 115 int flags; 116 gdb_xml_attribute_handler *handler; 117 const void *handler_data; 118 }; 119 120 /* Flags for elements. If no flags are specified, the element is 121 required exactly once. */ 122 123 enum gdb_xml_element_flag 124 { 125 GDB_XML_EF_NONE, 126 GDB_XML_EF_OPTIONAL = 1 << 0, /* The element is optional. */ 127 GDB_XML_EF_REPEATABLE = 1 << 1, /* The element is repeatable. */ 128 }; 129 130 /* A handler called at the beginning of an element. 131 132 PARSER is the current XML parser, which should be used to issue any 133 debugging or error messages. ELEMENT is the current element. 134 USER_DATA is the opaque pointer supplied when the parser was 135 created. ATTRIBUTES is a vector of the values of any attributes 136 attached to this element. 137 138 The start handler will only be called if all the required 139 attributes were present and parsed successfully, and elements of 140 ATTRIBUTES are guaranteed to be in the same order used in 141 ELEMENT->ATTRIBUTES (not the order from the XML file). Accordingly 142 fixed offsets can be used to find any non-optional attributes as 143 long as no optional attributes precede them. */ 144 145 typedef void (gdb_xml_element_start_handler) 146 (struct gdb_xml_parser *parser, const struct gdb_xml_element *element, 147 void *user_data, std::vector<gdb_xml_value> &attributes); 148 149 /* A handler called at the end of an element. 150 151 PARSER, ELEMENT, and USER_DATA are as for the start handler. BODY 152 is any accumulated body text inside the element, with leading and 153 trailing whitespace removed. It will never be NULL. */ 154 155 typedef void (gdb_xml_element_end_handler) 156 (struct gdb_xml_parser *, const struct gdb_xml_element *, 157 void *user_data, const char *body_text); 158 159 /* An expected element and the handlers to call when it is 160 encountered. Arrays of struct gdb_xml_element are terminated 161 by an entry with NAME == NULL. */ 162 163 struct gdb_xml_element 164 { 165 const char *name; 166 const struct gdb_xml_attribute *attributes; 167 const struct gdb_xml_element *children; 168 int flags; 169 170 gdb_xml_element_start_handler *start_handler; 171 gdb_xml_element_end_handler *end_handler; 172 }; 173 174 /* Parse a XML document. DOCUMENT is the data to parse, which should 175 be NUL-terminated. If non-NULL, use the compiled-in DTD named 176 DTD_NAME to drive the parsing. 177 178 The return value is 0 for success or -1 for error. It may throw, 179 but only if something unexpected goes wrong during parsing; parse 180 errors will be caught, warned about, and reported as failure. */ 181 182 int gdb_xml_parse_quick (const char *name, const char *dtd_name, 183 const struct gdb_xml_element *elements, 184 const char *document, void *user_data); 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 ATTRIBUTE_PRINTF (2, 3); 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 ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 3); 196 197 /* Find the attribute named NAME in the set of parsed attributes 198 ATTRIBUTES. Returns NULL if not found. */ 199 200 struct gdb_xml_value *xml_find_attribute 201 (std::vector<gdb_xml_value> &attributes, const char *name); 202 203 /* Parse an integer attribute into a ULONGEST. */ 204 205 extern gdb_xml_attribute_handler gdb_xml_parse_attr_ulongest; 206 207 /* Map NAME to VALUE. A struct gdb_xml_enum * should be saved as the 208 value of handler_data when using gdb_xml_parse_attr_enum to parse a 209 fixed list of possible strings. The list is terminated by an entry 210 with NAME == NULL. */ 211 212 struct gdb_xml_enum 213 { 214 const char *name; 215 ULONGEST value; 216 }; 217 218 /* A handler_data for yes/no boolean values. */ 219 extern const struct gdb_xml_enum gdb_xml_enums_boolean[]; 220 221 extern gdb_xml_attribute_handler gdb_xml_parse_attr_enum; 222 223 /* Parse an integer string into a ULONGEST and return it, or call 224 gdb_xml_error if it could not be parsed. */ 225 226 ULONGEST gdb_xml_parse_ulongest (struct gdb_xml_parser *parser, 227 const char *value); 228 229 /* Open FILENAME, read all its text into memory, close it, and return 230 the text. If something goes wrong, return an uninstantiated optional 231 and warn. */ 232 233 extern gdb::optional<gdb::char_vector> xml_fetch_content_from_file 234 (const char *filename, void *baton); 235 236 #endif 237