src/plugins/ctf/common/msg-iter/msg-iter.h

   1 #ifndef CTF_MSG_ITER_H
   2 #define CTF_MSG_ITER_H
   3
   4 /*
   5  * Babeltrace - CTF message iterator
   6  *
   7  * Copyright (c) 2015-2016 EfficiOS Inc. and Linux Foundation
   8  * Copyright (c) 2015-2016 Philippe Proulx <pproulx@efficios.com>
   9  *
  10  * Permission is hereby granted, free of charge, to any person obtaining a copy
  11  * of this software and associated documentation files (the "Software"), to deal
  12  * in the Software without restriction, including without limitation the rights
  13  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  14  * copies of the Software, and to permit persons to whom the Software is
  15  * furnished to do so, subject to the following conditions:
  16  *
  17  * The above copyright notice and this permission notice shall be included in
  18  * all copies or substantial portions of the Software.
  19  *
  20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  21  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  23  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  24  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  25  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  26  * SOFTWARE.
  27  */
  28
  29 #include <stdbool.h>
  30 #include <stdint.h>
  31 #include <stdio.h>
  32 #include <stddef.h>
  33 #include <babeltrace2/babeltrace.h>
  34 #include "common/macros.h"
  35
  36 #include "../metadata/ctf-meta.h"
  37
  38 /**
  39  * @file ctf-msg-iter.h
  40  *
  41  * CTF message iterator
  42  *
  43  * This is a common internal API used by CTF source plugins. It allows
  44  * one to get messages from a user-provided medium.
  45  */
  46
  47 /**
  48  * Medium operations status codes.
  49  */
  50 enum ctf_msg_iter_medium_status {
  51         /**
  52          * End of file.
  53          *
  54          * The medium function called by the message iterator
  55          * function reached the end of the file.
  56          */
  57         CTF_MSG_ITER_MEDIUM_STATUS_EOF = 1,
  58
  59         /**
  60          * There is no data available right now, try again later.
  61          */
  62         CTF_MSG_ITER_MEDIUM_STATUS_AGAIN = 11,
  63
  64         /** General error. */
  65         CTF_MSG_ITER_MEDIUM_STATUS_ERROR = -1,
  66
  67         /** Everything okay. */
  68         CTF_MSG_ITER_MEDIUM_STATUS_OK = 0,
  69 };
  70
  71 /**
  72  * CTF message iterator API status code.
  73  */
  74 enum ctf_msg_iter_status {
  75         /**
  76          * End of file.
  77          *
  78          * The medium function called by the message iterator
  79          * function reached the end of the file.
  80          */
  81         CTF_MSG_ITER_STATUS_EOF = CTF_MSG_ITER_MEDIUM_STATUS_EOF,
  82
  83         /**
  84          * There is no data available right now, try again later.
  85          *
  86          * Some condition resulted in the
  87          * ctf_msg_iter_medium_ops::request_bytes() user function not
  88          * having access to any data now. You should retry calling the
  89          * last called message iterator function once the situation
  90          * is resolved.
  91          */
  92         CTF_MSG_ITER_STATUS_AGAIN = CTF_MSG_ITER_MEDIUM_STATUS_AGAIN,
  93
  94         /** General error. */
  95         CTF_MSG_ITER_STATUS_ERROR = CTF_MSG_ITER_MEDIUM_STATUS_ERROR,
  96
  97         /** Everything okay. */
  98         CTF_MSG_ITER_STATUS_OK = CTF_MSG_ITER_MEDIUM_STATUS_OK,
  99 };
 100
 101 /**
 102  * Medium operations.
 103  *
 104  * Those user functions are called by the message iterator
 105  * functions to request medium actions.
 106  */
 107 struct ctf_msg_iter_medium_ops {
 108         /**
 109          * Returns the next byte buffer to be used by the binary file
 110          * reader to deserialize binary data.
 111          *
 112          * This function \em must be defined.
 113          *
 114          * The purpose of this function is to return a buffer of bytes
 115          * to the message iterator, of a maximum of \p request_sz
 116          * bytes. If this function cannot return a buffer of at least
 117          * \p request_sz bytes, it may return a smaller buffer. In
 118          * either cases, \p buffer_sz must be set to the returned buffer
 119          * size (in bytes).
 120          *
 121          * The returned buffer's ownership remains the medium, in that
 122          * it won't be freed by the message iterator functions. The
 123          * returned buffer won't be modified by the message
 124          * iterator functions either.
 125          *
 126          * When this function is called for the first time for a given
 127          * file, the offset within the file is considered to be 0. The
 128          * next times this function is called, the returned buffer's
 129          * byte offset within the complete file must be the previous
 130          * offset plus the last returned value of \p buffer_sz by this
 131          * medium.
 132          *
 133          * This function must return one of the following statuses:
 134          *
 135          *   - <b>#CTF_MSG_ITER_MEDIUM_STATUS_OK</b>: Everything
 136          *     is okay, i.e. \p buffer_sz is set to a positive value
 137          *     reflecting the number of available bytes in the buffer
 138          *     starting at the address written in \p buffer_addr.
 139          *   - <b>#CTF_MSG_ITER_MEDIUM_STATUS_AGAIN</b>: No data is
 140          *     available right now. In this case, the message
 141          *     iterator function called by the user returns
 142          *     #CTF_MSG_ITER_STATUS_AGAIN, and it is the user's
 143          *     responsibility to make sure enough data becomes available
 144          *     before calling the \em same message iterator
 145          *     function again to continue the decoding process.
 146          *   - <b>#CTF_MSG_ITER_MEDIUM_STATUS_EOF</b>: The end of
 147          *     the file was reached, and no more data will ever be
 148          *     available for this file. In this case, the message
 149          *     iterator function called by the user returns
 150          *     #CTF_MSG_ITER_STATUS_EOF. This must \em not be
 151          *     returned when returning at least one byte of data to the
 152          *     caller, i.e. this must be returned when there's
 153          *     absolutely nothing left; should the request size be
 154          *     larger than what's left in the file, this function must
 155          *     return what's left, setting \p buffer_sz to the number of
 156          *     remaining bytes, and return
 157          *     #CTF_MSG_ITER_MEDIUM_STATUS_EOF on the \em following
 158          *     call.
 159          *   - <b>#CTF_MSG_ITER_MEDIUM_STATUS_ERROR</b>: A fatal
 160          *     error occured during this operation. In this case, the
 161          *     message iterator function called by the user returns
 162          *     #CTF_MSG_ITER_STATUS_ERROR.
 163          *
 164          * If #CTF_MSG_ITER_MEDIUM_STATUS_OK is not returned, the
 165          * values of \p buffer_sz and \p buffer_addr are \em ignored by
 166          * the caller.
 167          *
 168          * @param request_sz    Requested buffer size (bytes)
 169          * @param buffer_addr   Returned buffer address
 170          * @param buffer_sz     Returned buffer's size (bytes)
 171          * @param data          User data
 172          * @returns             Status code (see description above)
 173          */
 174         enum ctf_msg_iter_medium_status (* request_bytes)(size_t request_sz,
 175                         uint8_t **buffer_addr, size_t *buffer_sz, void *data);
 176
 177         /**
 178          * Repositions the underlying stream's position.
 179          *
 180          * This *optional* method repositions the underlying stream
 181          * to a given absolute position in the medium.
 182          *
 183          * @param offset        Offset to use for the given directive
 184          * @param data          User data
 185          * @returns             One of #ctf_msg_iter_medium_status values
 186          */
 187         enum ctf_msg_iter_medium_status (* seek)(off_t offset, void *data);
 188
 189         /**
 190          * Returns a stream instance (weak reference) for the given
 191          * stream class.
 192          *
 193          * This is called after a packet header is read, and the
 194          * corresponding stream class is found by the message
 195          * iterator.
 196          *
 197          * @param stream_class  Stream class of the stream to get
 198          * @param stream_id     Stream (instance) ID of the stream
 199          *                      to get (-1ULL if not available)
 200          * @param data          User data
 201          * @returns             Stream instance (weak reference) or
 202          *                      \c NULL on error
 203          */
 204         bt_stream * (* borrow_stream)(bt_stream_class *stream_class,
 205                         int64_t stream_id, void *data);
 206 };
 207
 208 /** CTF message iterator. */
 209 struct ctf_msg_iter;
 210
 211 /**
 212  * Creates a CTF message iterator.
 213  *
 214  * Upon successful completion, the reference count of \p trace is
 215  * incremented.
 216  *
 217  * @param trace                 Trace to read
 218  * @param max_request_sz        Maximum buffer size, in bytes, to
 219  *                              request to
 220  *                              ctf_msg_iter_medium_ops::request_bytes()
 221  *                              at a time
 222  * @param medops                Medium operations
 223  * @param medops_data           User data (passed to medium operations)
 224  * @returns                     New CTF message iterator on
 225  *                              success, or \c NULL on error
 226  */
 227 BT_HIDDEN
 228 struct ctf_msg_iter *ctf_msg_iter_create(
 229                 struct ctf_trace_class *tc,
 230                 size_t max_request_sz,
 231                 struct ctf_msg_iter_medium_ops medops,
 232                 void *medops_data,
 233                 bt_logging_level log_level,
 234                 bt_self_component *self_comp,
 235                 bt_self_message_iterator *self_msg_iter);
 236
 237 /**
 238  * Destroys a CTF message iterator, freeing all internal resources.
 239  *
 240  * The registered trace's reference count is decremented.
 241  *
 242  * @param msg_iter              CTF message iterator
 243  */
 244 BT_HIDDEN
 245 void ctf_msg_iter_destroy(struct ctf_msg_iter *msg_iter);
 246
 247 /**
 248  * Returns the next message from a CTF message iterator.
 249  *
 250  * Upon successful completion, #CTF_MSG_ITER_STATUS_OK is
 251  * returned, and the next message is written to \p msg.
 252  * In this case, the caller is responsible for calling
 253  * bt_message_put() on the returned message.
 254  *
 255  * If this function returns #CTF_MSG_ITER_STATUS_AGAIN, the caller
 256  * should make sure that data becomes available to its medium, and
 257  * call this function again, until another status is returned.
 258  *
 259  * @param msg_iter              CTF message iterator
 260  * @param message               Returned message if the function's
 261  *                              return value is #CTF_MSG_ITER_STATUS_OK
 262  * @returns                     One of #ctf_msg_iter_status values
 263  */
 264 BT_HIDDEN
 265 enum ctf_msg_iter_status ctf_msg_iter_get_next_message(
 266                 struct ctf_msg_iter *msg_it,
 267                 const bt_message **message);
 268
 269 struct ctf_msg_iter_packet_properties {
 270         int64_t exp_packet_total_size;
 271         int64_t exp_packet_content_size;
 272         uint64_t stream_class_id;
 273         int64_t data_stream_id;
 274
 275         struct {
 276                 uint64_t discarded_events;
 277                 uint64_t packets;
 278                 uint64_t beginning_clock;
 279                 uint64_t end_clock;
 280         } snapshots;
 281 };
 282
 283 BT_HIDDEN
 284 enum ctf_msg_iter_status ctf_msg_iter_get_packet_properties(
 285                 struct ctf_msg_iter *msg_it,
 286                 struct ctf_msg_iter_packet_properties *props);
 287
 288 BT_HIDDEN
 289 enum ctf_msg_iter_status ctf_msg_iter_curr_packet_first_event_clock_snapshot(
 290                 struct ctf_msg_iter *msg_it, uint64_t *first_event_cs);
 291
 292 BT_HIDDEN
 293 enum ctf_msg_iter_status ctf_msg_iter_curr_packet_last_event_clock_snapshot(
 294                 struct ctf_msg_iter *msg_it, uint64_t *last_event_cs);
 295
 296 BT_HIDDEN
 297 void ctf_msg_iter_set_medops_data(struct ctf_msg_iter *msg_it,
 298                 void *medops_data);
 299
 300 BT_HIDDEN
 301 enum ctf_msg_iter_status ctf_msg_iter_seek(
 302                 struct ctf_msg_iter *msg_it, off_t offset);
 303
 304 /*
 305  * Resets the iterator so that the next requested medium bytes are
 306  * assumed to be the first bytes of a new stream. Depending on
 307  * ctf_msg_iter_set_emit_stream_beginning_message(), the first message
 308  * which this iterator emits after calling ctf_msg_iter_reset() is of
 309  * type `CTF_MESSAGE_TYPE_STREAM_BEGINNING`.
 310  */
 311 BT_HIDDEN
 312 void ctf_msg_iter_reset(struct ctf_msg_iter *msg_it);
 313
 314 /*
 315  * Like ctf_msg_iter_reset(), but preserves stream-dependent state.
 316  */
 317 BT_HIDDEN
 318 void ctf_msg_iter_reset_for_next_stream_file(struct ctf_msg_iter *msg_it);
 319
 320 BT_HIDDEN
 321 void ctf_msg_iter_set_emit_stream_beginning_message(struct ctf_msg_iter *msg_it,
 322                 bool val);
 323
 324 BT_HIDDEN
 325 void ctf_msg_iter_set_emit_stream_end_message(struct ctf_msg_iter *msg_it,
 326                 bool val);
 327
 328 BT_HIDDEN
 329 void ctf_msg_iter_set_dry_run(struct ctf_msg_iter *msg_it,
 330                 bool val);
 331
 332 static inline
 333 const char *ctf_msg_iter_medium_status_string(
 334                 enum ctf_msg_iter_medium_status status)
 335 {
 336         switch (status) {
 337         case CTF_MSG_ITER_MEDIUM_STATUS_EOF:
 338                 return "EOF";
 339         case CTF_MSG_ITER_MEDIUM_STATUS_AGAIN:
 340                 return "AGAIN";
 341         case CTF_MSG_ITER_MEDIUM_STATUS_ERROR:
 342                 return "ERROR";
 343         case CTF_MSG_ITER_MEDIUM_STATUS_OK:
 344                 return "OK";
 345         default:
 346                 return "(unknown)";
 347         }
 348 }
 349
 350 static inline
 351 const char *ctf_msg_iter_status_string(
 352                 enum ctf_msg_iter_status status)
 353 {
 354         switch (status) {
 355         case CTF_MSG_ITER_STATUS_EOF:
 356                 return "EOF";
 357         case CTF_MSG_ITER_STATUS_AGAIN:
 358                 return "AGAIN";
 359         case CTF_MSG_ITER_STATUS_ERROR:
 360                 return "ERROR";
 361         case CTF_MSG_ITER_STATUS_OK:
 362                 return "OK";
 363         default:
 364                 return "(unknown)";
 365         }
 366 }
 367
 368 #endif /* CTF_MSG_ITER_H */