include/babeltrace/ctf-ir/packet.h

   1 #ifndef BABELTRACE_CTF_IR_PACKET_H
   2 #define BABELTRACE_CTF_IR_PACKET_H
   3
   4 /*
   5  * BabelTrace - CTF IR: Stream packet
   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 /**
  38 @defgroup ctfirpacket CTF IR packet
  39 @ingroup ctfir
  40 @brief CTF IR packet.
  41
  42 @code
  43 #include <babeltrace/ctf-ir/packet.h>
  44 @endcode
  45
  46 A CTF IR <strong><em>packet</em></strong> is a container of packet
  47 fields, that is, of the <strong>trace packet header</strong> and
  48 <strong>stream packet context</strong> fields.
  49
  50 As a reminder, here's the structure of a CTF packet:
  51
  52 @imgpacketstructure
  53
  54 You can create a CTF IR packet \em from a
  55 \link ctfirstream CTF IR stream\endlink with bt_ctf_packet_create(). The
  56 stream you use to create a packet object becomes its parent.
  57
  58 When you set the trace packet header and stream packet context fields of
  59 a packet with resp. bt_ctf_packet_set_header() and
  60 bt_ctf_packet_set_context(), their field type \em must be equivalent to
  61 the field types returned by resp. bt_ctf_trace_get_packet_header_type()
  62 and bt_ctf_stream_class_get_packet_context_type() for its parent trace
  63 class and stream class.
  64
  65 You can attach a packet object to a \link ctfirevent CTF IR
  66 event\endlink object with bt_ctf_event_set_packet().
  67
  68 As with any Babeltrace object, CTF IR packet objects have
  69 <a href="https://en.wikipedia.org/wiki/Reference_counting">reference
  70 counts</a>. See \ref refs to learn more about the reference counting
  71 management of Babeltrace objects.
  72
  73 bt_notification_event_create() \em freezes its event parameter on
  74 success, which in turns freezes the event's associated packet object.
  75 This is the only way that a CTF IR packet object can be frozen.
  76 You cannot modify a frozen packet: it is considered immutable,
  77 except for \link refs reference counting\endlink.
  78
  79 @sa ctfirstream
  80 @sa ctfirstreamclass
  81 @sa ctfirtraceclass
  82
  83 @file
  84 @brief CTF IR packet type and functions.
  85 @sa ctfirpacket
  86
  87 @addtogroup ctfirpacket
  88 @{
  89 */
  90
  91 /**
  92 @struct bt_ctf_packet
  93 @brief A CTF IR packet.
  94 @sa ctfirpacket
  95 */
  96 struct bt_ctf_packet;
  97 struct bt_ctf_stream;
  98
  99 /**
 100 @name Creation and parent access functions
 101 @{
 102 */
 103
 104 /**
 105 @brief  Creates a default CTF IR packet with \p stream as its parent
 106         CTF IR stream.
 107
 108 On success, the packet object's trace packet header and stream packet
 109 context fields are not set. You can set them with resp.
 110 bt_ctf_packet_set_header() and bt_ctf_packet_set_context().
 111
 112 @param[in] stream       Parent CTF IR stream of the packet to create.
 113 @returns                Created packet, or \c NULL on error.
 114
 115 @prenotnull{stream}
 116 @postsuccessrefcountret1
 117 */
 118 extern struct bt_ctf_packet *bt_ctf_packet_create(
 119                 struct bt_ctf_stream *stream);
 120
 121 /**
 122 @brief  Returns the parent CTF IR stream of the CTF IR packet \p packet.
 123
 124 This function returns a reference to the stream which was used to create
 125 the packet object in the first place with bt_ctf_packet_create().
 126
 127 @param[in] packet       Packet of which to get the parent stream.
 128 @returns                Parent stream of \p packet, or \c NULL on error.
 129
 130 @prenotnull{packet}
 131 @postsuccessrefcountretinc
 132 */
 133 extern struct bt_ctf_stream *bt_ctf_packet_get_stream(
 134                 struct bt_ctf_packet *packet);
 135
 136 /** @} */
 137
 138 /**
 139 @name Contained fields functions
 140 @{
 141 */
 142
 143 /**
 144 @brief  Returns the trace packet header field of the CTF IR packet
 145         \p packet.
 146
 147 @param[in] packet       Packet of which to get the trace packet header
 148                         field.
 149 @returns                Trace packet header field of \p packet,
 150                         or \c NULL if the trace packet header
 151                         field is not set or on error.
 152
 153 @prenotnull{packet}
 154 @postsuccessrefcountretinc
 155
 156 @sa bt_ctf_packet_set_header(): Sets the trace packet header
 157         field of a given packet.
 158 */
 159 extern struct bt_ctf_field *bt_ctf_packet_get_header(
 160                 struct bt_ctf_packet *packet);
 161
 162 /**
 163 @brief  Sets the trace packet header field of the CTF IR packet
 164         \p packet to \p header.
 165
 166 The field type of \p header, as returned by bt_ctf_field_get_type(),
 167 \em must be equivalent to the field type returned by
 168 bt_ctf_trace_get_packet_header_type() for the parent trace class
 169 of \p packet.
 170
 171 @param[in] packet       Packet of which to set the trace packet header
 172                         field.
 173 @param[in] header       Trace packet header field.
 174 @returns                0 on success, or a negative value on error.
 175
 176 @prenotnull{packet}
 177 @prenotnull{header}
 178 @prehot{packet}
 179 @pre \p header has a field type equivalent to the field type returned by
 180         bt_ctf_trace_get_packet_header_type() for the parent trace class
 181         of \p packet.
 182 @postrefcountsame{packet}
 183 @postsuccessrefcountinc{header}
 184
 185 @sa bt_ctf_packet_get_header(): Returns the trace packet header field
 186         of a given packet.
 187 */
 188 extern int bt_ctf_packet_set_header(
 189                 struct bt_ctf_packet *packet, struct bt_ctf_field *header);
 190
 191 /**
 192 @brief  Returns the stream packet context field of the CTF IR packet
 193         \p packet.
 194
 195 @param[in] packet       Packet of which to get the stream packet context
 196                         field.
 197 @returns                Stream packet context field of \p packet,
 198                         or \c NULL if the stream packet context
 199                         field is not set or on error.
 200
 201 @prenotnull{packet}
 202 @postsuccessrefcountretinc
 203
 204 @sa bt_ctf_packet_set_context(): Sets the stream packet context
 205         field of a given packet.
 206 */
 207 extern struct bt_ctf_field *bt_ctf_packet_get_context(
 208                 struct bt_ctf_packet *packet);
 209
 210 /**
 211 @brief  Sets the stream packet context field of the CTF IR packet
 212         \p packet to \p context.
 213
 214 The field type of \p context, as returned by bt_ctf_field_get_type(),
 215 \em must be equivalent to the field type returned by
 216 bt_ctf_stream_class_get_packet_context_type() for the parent stream
 217 class of \p packet.
 218
 219 @param[in] packet       Packet of which to set the stream packet context
 220                         field.
 221 @param[in] context      Stream packet context field.
 222 @returns                0 on success, or a negative value on error.
 223
 224 @prenotnull{packet}
 225 @prenotnull{context}
 226 @prehot{packet}
 227 @pre \p context has a field type equivalent to the field type returned
 228         by bt_ctf_stream_class_get_packet_context_type() for the parent
 229         stream class of \p packet.
 230 @postrefcountsame{packet}
 231 @postsuccessrefcountinc{context}
 232
 233 @sa bt_ctf_packet_get_context(): Returns the stream packet context field
 234         of a given packet.
 235 */
 236 extern int bt_ctf_packet_set_context(
 237                 struct bt_ctf_packet *packet, struct bt_ctf_field *context);
 238
 239 /** @} */
 240
 241 #ifdef __cplusplus
 242 }
 243 #endif
 244
 245 #endif /* BABELTRACE_CTF_IR_PACKET_H */