include/babeltrace/ctf-ir/field-path.h

   1 #ifndef BABELTRACE_CTF_IR_FIELD_PATH_H
   2 #define BABELTRACE_CTF_IR_FIELD_PATH_H
   3
   4 /*
   5  * BabelTrace - CTF IR: Field path
   6  *
   7  * Copyright 2016 Philippe Proulx <pproulx@efficios.com>
   8  *
   9  * Permission is hereby granted, free of charge, to any person obtaining a copy
  10  * of this software and associated documentation files (the "Software"), to deal
  11  * in the Software without restriction, including without limitation the rights
  12  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  13  * copies of the Software, and to permit persons to whom the Software is
  14  * furnished to do so, subject to the following conditions:
  15  *
  16  * The above copyright notice and this permission notice shall be included in
  17  * all copies or substantial portions of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  22  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  23  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  24  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  25  * SOFTWARE.
  26  *
  27  * The Common Trace Format (CTF) Specification is available at
  28  * http://www.efficios.com/ctf
  29  */
  30
  31 #include <stdint.h>
  32
  33 #ifdef __cplusplus
  34 extern "C" {
  35 #endif
  36
  37 struct bt_field_type;
  38
  39 /**
  40 @defgroup ctfirfieldpath CTF IR field path
  41 @ingroup ctfir
  42 @brief CTF IR field path.
  43
  44 @code
  45 #include <babeltrace/ctf-ir/field-path.h>
  46 @endcode
  47
  48 A CTF IR <strong><em>field path</em></strong> represents an absolute
  49 path to a field in the hierarchy of a
  50 \link ctfirtraceclass CTF IR trace class\endlink, of a
  51 \link ctfirstreamclass CTF IR stream class\endlink, or of a
  52 \link ctfireventclass CTF IR event class\endlink.
  53
  54 As a reminder, here's the structure of a CTF packet:
  55
  56 @imgpacketstructure
  57
  58 Sequence and variant \link ctfirfieldtypes CTF IR field types\endlink
  59 can return a field path to resp. their length field and tag field
  60 with resp. bt_field_type_sequence_get_length_field_path() and
  61 bt_field_type_variant_get_tag_field_path().
  62
  63 A field path has a <em>root scope</em> which indicates from which of the
  64 six CTF scopes to begin. It also has a list of structure field <em>path
  65 indexes</em> which indicate the path to take to reach the destination
  66 field. A path index set to -1 means that you need to continue the lookup
  67 within the current element of an array or sequence field.
  68
  69 As with any Babeltrace object, CTF IR field path objects have
  70 <a href="https://en.wikipedia.org/wiki/Reference_counting">reference
  71 counts</a>. See \ref refs to learn more about the reference counting
  72 management of Babeltrace objects.
  73
  74 @file
  75 @brief CTF IR field path type and functions.
  76 @sa ctfirfieldpath
  77
  78 @addtogroup ctfirfieldpath
  79 @{
  80 */
  81
  82 /**
  83 @struct bt_field_path
  84 @brief A CTF IR field path.
  85 @sa ctfirfieldpath
  86 */
  87 struct bt_field_path;
  88
  89 /**
  90 @brief  Returns the root scope of the CTF IR field path \p field_path.
  91
  92 @param[in] field_path   Field path of which to get the root scope.
  93 @returns                Root scope of \p field_path, or
  94                         #BT_SCOPE_UNKNOWN on error.
  95
  96 @prenotnull{field_path}
  97 @postrefcountsame{field_path}
  98 */
  99 extern enum bt_scope bt_field_path_get_root_scope(
 100                 const struct bt_field_path *field_path);
 101
 102 /**
 103 @brief  Returns the number of path indexes contained in the CTF IR field
 104         path \p field_path.
 105
 106 @param[in] field_path   Field path of which to get the number of
 107                         path indexes.
 108 @returns                Number of path indexes contained in
 109                         \p field_path, or a negative value on error.
 110
 111 @prenotnull{field_path}
 112 @postrefcountsame{field_path}
 113 */
 114 extern int64_t bt_field_path_get_index_count(
 115                 const struct bt_field_path *field_path);
 116
 117 /**
 118 @brief  Returns the path index contained in the CTF IR field
 119         path \p field_path at index \p index.
 120
 121 @param[in] field_path   Field path of which to get the path index
 122                         at index \p index.
 123 @param[in] index        Index of path index to get.
 124 @returns                Path index of \p field_path at index \p index,
 125                         or \c INT_MIN on error.
 126
 127 @prenotnull{field_path}
 128 @pre \p index is lesser than the number of path indexes contained in the
 129         field path \p field_path (see
 130         bt_field_path_get_index_count()).
 131 @postrefcountsame{field_path}
 132 */
 133 extern int bt_field_path_get_index(
 134                 const struct bt_field_path *field_path, uint64_t index);
 135
 136 /** @} */
 137
 138 #ifdef __cplusplus
 139 }
 140 #endif
 141
 142 #endif /* BABELTRACE_CTF_IR_FIELD_PATH_H */