include/apr_xml.h

   1 /* Licensed to the Apache Software Foundation (ASF) under one or more
   2  * contributor license agreements.  See the NOTICE file distributed with
   3  * this work for additional information regarding copyright ownership.
   4  * The ASF licenses this file to You under the Apache License, Version 2.0
   5  * (the "License"); you may not use this file except in compliance with
   6  * the License.  You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 /**
  17  * @file apr_xml.h
  18  * @brief APR-UTIL XML Library
  19  */
  20 #ifndef APR_XML_H
  21 #define APR_XML_H
  22
  23 /**
  24  * @defgroup APR_Util_XML XML
  25  * @ingroup APR_Util
  26  * @{
  27  */
  28 #include "apr_pools.h"
  29 #include "apr_tables.h"
  30 #include "apr_file_io.h"
  31
  32 #include "apu.h"
  33 #if APR_CHARSET_EBCDIC
  34 #include "apr_xlate.h"
  35 #endif
  36
  37 #ifdef __cplusplus
  38 extern "C" {
  39 #endif
  40
  41 /**
  42  * @package Apache XML library
  43  */
  44
  45 /* -------------------------------------------------------------------- */
  46
  47 /* ### these will need to move at some point to a more logical spot */
  48
  49 /** @see apr_text */
  50 typedef struct apr_text apr_text;
  51
  52 /** Structure to keep a linked list of pieces of text */
  53 struct apr_text {
  54     /** The current piece of text */
  55     const char *text;
  56     /** a pointer to the next piece of text */
  57     struct apr_text *next;
  58 };
  59
  60 /** @see apr_text_header */
  61 typedef struct apr_text_header apr_text_header;
  62
  63 /** A list of pieces of text */
  64 struct apr_text_header {
  65     /** The first piece of text in the list */
  66     apr_text *first;
  67     /** The last piece of text in the list */
  68     apr_text *last;
  69 };
  70
  71 /**
  72  * Append a piece of text to the end of a list
  73  * @param p The pool to allocate out of
  74  * @param hdr The text header to append to
  75  * @param text The new text to append
  76  */
  77 APU_DECLARE(void) apr_text_append(apr_pool_t *p, apr_text_header *hdr,
  78                                   const char *text);
  79
  80
  81 /* --------------------------------------------------------------------
  82 **
  83 ** XML PARSING
  84 */
  85
  86 /*
  87 ** Qualified namespace values
  88 **
  89 ** APR_XML_NS_DAV_ID
  90 **    We always insert the "DAV:" namespace URI at the head of the
  91 **    namespace array. This means that it will always be at ID==0,
  92 **    making it much easier to test for.
  93 **
  94 ** APR_XML_NS_NONE
  95 **    This special ID is used for two situations:
  96 **
  97 **    1) The namespace prefix begins with "xml" (and we do not know
  98 **       what it means). Namespace prefixes with "xml" (any case) as
  99 **       their first three characters are reserved by the XML Namespaces
 100 **       specification for future use. mod_dav will pass these through
 101 **       unchanged. When this identifier is used, the prefix is LEFT in
 102 **       the element/attribute name. Downstream processing should not
 103 **       prepend another prefix.
 104 **
 105 **    2) The element/attribute does not have a namespace.
 106 **
 107 **       a) No prefix was used, and a default namespace has not been
 108 **          defined.
 109 **       b) No prefix was used, and the default namespace was specified
 110 **          to mean "no namespace". This is done with a namespace
 111 **          declaration of:  xmlns=""
 112 **          (this declaration is typically used to override a previous
 113 **          specification for the default namespace)
 114 **
 115 **       In these cases, we need to record that the elem/attr has no
 116 **       namespace so that we will not attempt to prepend a prefix.
 117 **       All namespaces that are used will have a prefix assigned to
 118 **       them -- mod_dav will never set or use the default namespace
 119 **       when generating XML. This means that "no prefix" will always
 120 **       mean "no namespace".
 121 **
 122 **    In both cases, the XML generation will avoid prepending a prefix.
 123 **    For the first case, this means the original prefix/name will be
 124 **    inserted into the output stream. For the latter case, it means
 125 **    the name will have no prefix, and since we never define a default
 126 **    namespace, this means it will have no namespace.
 127 **
 128 ** Note: currently, mod_dav understands the "xmlns" prefix and the
 129 **     "xml:lang" attribute. These are handled specially (they aren't
 130 **     left within the XML tree), so the APR_XML_NS_NONE value won't ever
 131 **     really apply to these values.
 132 */
 133 #define APR_XML_NS_DAV_ID       0       /**< namespace ID for "DAV:" */
 134 #define APR_XML_NS_NONE         -10     /**< no namespace for this elem/attr */
 135
 136 #define APR_XML_NS_ERROR_BASE   -100    /**< used only during processing */
 137 /** Is this namespace an error? */
 138 #define APR_XML_NS_IS_ERROR(e)  ((e) <= APR_XML_NS_ERROR_BASE)
 139
 140 /** @see apr_xml_attr */
 141 typedef struct apr_xml_attr apr_xml_attr;
 142 /** @see apr_xml_elem */
 143 typedef struct apr_xml_elem apr_xml_elem;
 144 /** @see apr_xml_doc */
 145 typedef struct apr_xml_doc apr_xml_doc;
 146
 147 /** apr_xml_attr: holds a parsed XML attribute */
 148 struct apr_xml_attr {
 149     /** attribute name */
 150     const char *name;
 151     /** index into namespace array */
 152     int ns;
 153
 154     /** attribute value */
 155     const char *value;
 156
 157     /** next attribute */
 158     struct apr_xml_attr *next;
 159 };
 160
 161 /** apr_xml_elem: holds a parsed XML element */
 162 struct apr_xml_elem {
 163     /** element name */
 164     const char *name;
 165     /** index into namespace array */
 166     int ns;
 167     /** xml:lang for attrs/contents */
 168     const char *lang;
 169
 170     /** cdata right after start tag */
 171     apr_text_header first_cdata;
 172     /** cdata after MY end tag */
 173     apr_text_header following_cdata;
 174
 175     /** parent element */
 176     struct apr_xml_elem *parent;
 177     /** next (sibling) element */
 178     struct apr_xml_elem *next;
 179     /** first child element */
 180     struct apr_xml_elem *first_child;
 181     /** first attribute */
 182     struct apr_xml_attr *attr;
 183
 184     /* used only during parsing */
 185     /** last child element */
 186     struct apr_xml_elem *last_child;
 187     /** namespaces scoped by this elem */
 188     struct apr_xml_ns_scope *ns_scope;
 189
 190     /* used by modules during request processing */
 191     /** Place for modules to store private data */
 192     void *priv;
 193 };
 194
 195 /** Is this XML element empty? */
 196 #define APR_XML_ELEM_IS_EMPTY(e) ((e)->first_child == NULL && \
 197                                   (e)->first_cdata.first == NULL)
 198
 199 /** apr_xml_doc: holds a parsed XML document */
 200 struct apr_xml_doc {
 201     /** root element */
 202     apr_xml_elem *root;
 203     /** array of namespaces used */
 204     apr_array_header_t *namespaces;
 205 };
 206
 207 /** Opaque XML parser structure */
 208 typedef struct apr_xml_parser apr_xml_parser;
 209
 210 /**
 211  * Create an XML parser
 212  * @param pool The pool for allocating the parser and the parse results.
 213  * @return The new parser.
 214  */
 215 APU_DECLARE(apr_xml_parser *) apr_xml_parser_create(apr_pool_t *pool);
 216
 217 /**
 218  * Parse a File, producing a xml_doc
 219  * @param p      The pool for allocating the parse results.
 220  * @param parser A pointer to *parser (needed so calling function can get
 221  *               errors), will be set to NULL on successfull completion.
 222  * @param ppdoc  A pointer to *apr_xml_doc (which has the parsed results in it)
 223  * @param xmlfd  A file to read from.
 224  * @param buffer_length Buffer length which would be suitable
 225  * @return Any errors found during parsing.
 226  */
 227 APU_DECLARE(apr_status_t) apr_xml_parse_file(apr_pool_t *p,
 228                                              apr_xml_parser **parser,
 229                                              apr_xml_doc **ppdoc,
 230                                              apr_file_t *xmlfd,
 231                                              apr_size_t buffer_length);
 232
 233
 234 /**
 235  * Feed input into the parser
 236  * @param parser The XML parser for parsing this data.
 237  * @param data The data to parse.
 238  * @param len The length of the data.
 239  * @return Any errors found during parsing.
 240  * @remark Use apr_xml_parser_geterror() to get more error information.
 241  */
 242 APU_DECLARE(apr_status_t) apr_xml_parser_feed(apr_xml_parser *parser,
 243                                               const char *data,
 244                                               apr_size_t len);
 245
 246 /**
 247  * Terminate the parsing and return the result
 248  * @param parser The XML parser for parsing this data.
 249  * @param pdoc The resulting parse information. May be NULL to simply
 250  *             terminate the parsing without fetching the info.
 251  * @return Any errors found during the final stage of parsing.
 252  * @remark Use apr_xml_parser_geterror() to get more error information.
 253  */
 254 APU_DECLARE(apr_status_t) apr_xml_parser_done(apr_xml_parser *parser,
 255                                               apr_xml_doc **pdoc);
 256
 257 /**
 258  * Fetch additional error information from the parser.
 259  * @param parser The XML parser to query for errors.
 260  * @param errbuf A buffer for storing error text.
 261  * @param errbufsize The length of the error text buffer.
 262  * @return The error buffer
 263  */
 264 APU_DECLARE(char *) apr_xml_parser_geterror(apr_xml_parser *parser,
 265                                             char *errbuf,
 266                                             apr_size_t errbufsize);
 267
 268
 269 /**
 270  * Converts an XML element tree to flat text
 271  * @param p The pool to allocate out of
 272  * @param elem The XML element to convert
 273  * @param style How to covert the XML.  One of:
 274  * <PRE>
 275  *     APR_XML_X2T_FULL                start tag, contents, end tag
 276  *     APR_XML_X2T_INNER               contents only
 277  *     APR_XML_X2T_LANG_INNER          xml:lang + inner contents
 278  *     APR_XML_X2T_FULL_NS_LANG        FULL + ns defns + xml:lang
 279  * </PRE>
 280  * @param namespaces The namespace of the current XML element
 281  * @param ns_map Namespace mapping
 282  * @param pbuf Buffer to put the converted text into
 283  * @param psize Size of the converted text
 284  */
 285 APU_DECLARE(void) apr_xml_to_text(apr_pool_t *p, const apr_xml_elem *elem,
 286                                   int style, apr_array_header_t *namespaces,
 287                                   int *ns_map, const char **pbuf,
 288                                   apr_size_t *psize);
 289
 290 /* style argument values: */
 291 #define APR_XML_X2T_FULL         0      /**< start tag, contents, end tag */
 292 #define APR_XML_X2T_INNER        1      /**< contents only */
 293 #define APR_XML_X2T_LANG_INNER   2      /**< xml:lang + inner contents */
 294 #define APR_XML_X2T_FULL_NS_LANG 3      /**< FULL + ns defns + xml:lang */
 295
 296 /**
 297  * empty XML element
 298  * @param p The pool to allocate out of
 299  * @param elem The XML element to empty
 300  * @return the string that was stored in the XML element
 301  */
 302 APU_DECLARE(const char *) apr_xml_empty_elem(apr_pool_t *p,
 303                                              const apr_xml_elem *elem);
 304
 305 /**
 306  * quote an XML string
 307  * Replace '<', '>', and '&' with '&lt;', '&gt;', and '&amp;'.
 308  * @param p The pool to allocate out of
 309  * @param s The string to quote
 310  * @param quotes If quotes is true, then replace '"' with '&quot;'.
 311  * @return The quoted string
 312  * @note If the string does not contain special characters, it is not
 313  * duplicated into the pool and the original string is returned.
 314  */
 315 APU_DECLARE(const char *) apr_xml_quote_string(apr_pool_t *p, const char *s,
 316                                                int quotes);
 317
 318 /**
 319  * Quote an XML element
 320  * @param p The pool to allocate out of
 321  * @param elem The element to quote
 322  */
 323 APU_DECLARE(void) apr_xml_quote_elem(apr_pool_t *p, apr_xml_elem *elem);
 324
 325 /* manage an array of unique URIs: apr_xml_insert_uri() and APR_XML_URI_ITEM() */
 326
 327 /**
 328  * return the URI's (existing) index, or insert it and return a new index
 329  * @param uri_array array to insert into
 330  * @param uri The uri to insert
 331  * @return int The uri's index
 332  */
 333 APU_DECLARE(int) apr_xml_insert_uri(apr_array_header_t *uri_array,
 334                                     const char *uri);
 335
 336 /** Get the URI item for this XML element */
 337 #define APR_XML_GET_URI_ITEM(ary, i) (((const char * const *)(ary)->elts)[i])
 338
 339 #if APR_CHARSET_EBCDIC
 340 /**
 341  * Convert parsed tree in EBCDIC
 342  * @param p The pool to allocate out of
 343  * @param pdoc The apr_xml_doc to convert.
 344  * @param xlate The translation handle to use.
 345  * @return Any errors found during conversion.
 346  */
 347 APU_DECLARE(apr_status_t) apr_xml_parser_convert_doc(apr_pool_t *p,
 348                                                      apr_xml_doc *pdoc,
 349                                                      apr_xlate_t *convset);
 350 #endif
 351
 352 #ifdef __cplusplus
 353 }
 354 #endif
 355 /** @} */
 356 #endif /* APR_XML_H */