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         /** Unsupported operation. */
  65         CTF_MSG_ITER_MEDIUM_STATUS_UNSUPPORTED = -3,
  66
  67         /** Invalid argument. */
  68         CTF_MSG_ITER_MEDIUM_STATUS_INVAL = -2,
  69
  70         /** General error. */
  71         CTF_MSG_ITER_MEDIUM_STATUS_ERROR = -1,
  72
  73         /** Everything okay. */
  74         CTF_MSG_ITER_MEDIUM_STATUS_OK = 0,
  75 };
  76
  77 /**
  78  * CTF message iterator API status code.
  79  */
  80 enum ctf_msg_iter_status {
  81         /**
  82          * End of file.
  83          *
  84          * The medium function called by the message iterator
  85          * function reached the end of the file.
  86          */
  87         CTF_MSG_ITER_STATUS_EOF = CTF_MSG_ITER_MEDIUM_STATUS_EOF,
  88
  89         /**
  90          * There is no data available right now, try again later.
  91          *
  92          * Some condition resulted in the
  93          * ctf_msg_iter_medium_ops::request_bytes() user function not
  94          * having access to any data now. You should retry calling the
  95          * last called message iterator function once the situation
  96          * is resolved.
  97          */
  98         CTF_MSG_ITER_STATUS_AGAIN = CTF_MSG_ITER_MEDIUM_STATUS_AGAIN,
  99
 100         /** Invalid argument. */
 101         CTF_MSG_ITER_STATUS_INVAL = CTF_MSG_ITER_MEDIUM_STATUS_INVAL,
 102
 103         /** Unsupported operation. */
 104         CTF_MSG_ITER_STATUS_UNSUPPORTED = CTF_MSG_ITER_MEDIUM_STATUS_UNSUPPORTED,
 105
 106         /** General error. */
 107         CTF_MSG_ITER_STATUS_ERROR = CTF_MSG_ITER_MEDIUM_STATUS_ERROR,
 108
 109         /** Everything okay. */
 110         CTF_MSG_ITER_STATUS_OK = CTF_MSG_ITER_MEDIUM_STATUS_OK,
 111 };
 112
 113 /**
 114  * Medium operations.
 115  *
 116  * Those user functions are called by the message iterator
 117  * functions to request medium actions.
 118  */
 119 struct ctf_msg_iter_medium_ops {
 120         /**
 121          * Returns the next byte buffer to be used by the binary file
 122          * reader to deserialize binary data.
 123          *
 124          * This function \em must be defined.
 125          *
 126          * The purpose of this function is to return a buffer of bytes
 127          * to the message iterator, of a maximum of \p request_sz
 128          * bytes. If this function cannot return a buffer of at least
 129          * \p request_sz bytes, it may return a smaller buffer. In
 130          * either cases, \p buffer_sz must be set to the returned buffer
 131          * size (in bytes).
 132          *
 133          * The returned buffer's ownership remains the medium, in that
 134          * it won't be freed by the message iterator functions. The
 135          * returned buffer won't be modified by the message
 136          * iterator functions either.
 137          *
 138          * When this function is called for the first time for a given
 139          * file, the offset within the file is considered to be 0. The
 140          * next times this function is called, the returned buffer's
 141          * byte offset within the complete file must be the previous
 142          * offset plus the last returned value of \p buffer_sz by this
 143          * medium.
 144          *
 145          * This function must return one of the following statuses:
 146          *
 147          *   - <b>#CTF_MSG_ITER_MEDIUM_STATUS_OK</b>: Everything
 148          *     is okay, i.e. \p buffer_sz is set to a positive value
 149          *     reflecting the number of available bytes in the buffer
 150          *     starting at the address written in \p buffer_addr.
 151          *   - <b>#CTF_MSG_ITER_MEDIUM_STATUS_AGAIN</b>: No data is
 152          *     available right now. In this case, the message
 153          *     iterator function called by the user returns
 154          *     #CTF_MSG_ITER_STATUS_AGAIN, and it is the user's
 155          *     responsibility to make sure enough data becomes available
 156          *     before calling the \em same message iterator
 157          *     function again to continue the decoding process.
 158          *   - <b>#CTF_MSG_ITER_MEDIUM_STATUS_EOF</b>: The end of
 159          *     the file was reached, and no more data will ever be
 160          *     available for this file. In this case, the message
 161          *     iterator function called by the user returns
 162          *     #CTF_MSG_ITER_STATUS_EOF. This must \em not be
 163          *     returned when returning at least one byte of data to the
 164          *     caller, i.e. this must be returned when there's
 165          *     absolutely nothing left; should the request size be
 166          *     larger than what's left in the file, this function must
 167          *     return what's left, setting \p buffer_sz to the number of
 168          *     remaining bytes, and return
 169          *     #CTF_MSG_ITER_MEDIUM_STATUS_EOF on the \em following
 170          *     call.
 171          *   - <b>#CTF_MSG_ITER_MEDIUM_STATUS_ERROR</b>: A fatal
 172          *     error occured during this operation. In this case, the
 173          *     message iterator function called by the user returns
 174          *     #CTF_MSG_ITER_STATUS_ERROR.
 175          *
 176          * If #CTF_MSG_ITER_MEDIUM_STATUS_OK is not returned, the
 177          * values of \p buffer_sz and \p buffer_addr are \em ignored by
 178          * the caller.
 179          *
 180          * @param request_sz    Requested buffer size (bytes)
 181          * @param buffer_addr   Returned buffer address
 182          * @param buffer_sz     Returned buffer's size (bytes)
 183          * @param data          User data
 184          * @returns             Status code (see description above)
 185          */
 186         enum ctf_msg_iter_medium_status (* request_bytes)(size_t request_sz,
 187                         uint8_t **buffer_addr, size_t *buffer_sz, void *data);
 188
 189         /**
 190          * Repositions the underlying stream's position.
 191          *
 192          * This *optional* method repositions the underlying stream
 193          * to a given absolute position in the medium.
 194          *
 195          * @param offset        Offset to use for the given directive
 196          * @param data          User data
 197          * @returns             One of #ctf_msg_iter_medium_status values
 198          */
 199         enum ctf_msg_iter_medium_status (* seek)(off_t offset, void *data);
 200
 201         /**
 202          * Returns a stream instance (weak reference) for the given
 203          * stream class.
 204          *
 205          * This is called after a packet header is read, and the
 206          * corresponding stream class is found by the message
 207          * iterator.
 208          *
 209          * @param stream_class  Stream class of the stream to get
 210          * @param stream_id     Stream (instance) ID of the stream
 211          *                      to get (-1ULL if not available)
 212          * @param data          User data
 213          * @returns             Stream instance (weak reference) or
 214          *                      \c NULL on error
 215          */
 216         bt_stream * (* borrow_stream)(bt_stream_class *stream_class,
 217                         int64_t stream_id, void *data);
 218 };
 219
 220 /** CTF message iterator. */
 221 struct ctf_msg_iter;
 222
 223 /**
 224  * Creates a CTF message iterator.
 225  *
 226  * Upon successful completion, the reference count of \p trace is
 227  * incremented.
 228  *
 229  * @param trace                 Trace to read
 230  * @param max_request_sz        Maximum buffer size, in bytes, to
 231  *                              request to
 232  *                              ctf_msg_iter_medium_ops::request_bytes()
 233  *                              at a time
 234  * @param medops                Medium operations
 235  * @param medops_data           User data (passed to medium operations)
 236  * @returns                     New CTF message iterator on
 237  *                              success, or \c NULL on error
 238  */
 239 BT_HIDDEN
 240 struct ctf_msg_iter *ctf_msg_iter_create(
 241                 struct ctf_trace_class *tc,
 242                 size_t max_request_sz,
 243                 struct ctf_msg_iter_medium_ops medops,
 244                 void *medops_data,
 245                 bt_logging_level log_level,
 246                 bt_self_component *self_comp,
 247                 bt_self_message_iterator *self_msg_iter);
 248
 249 /**
 250  * Destroys a CTF message iterator, freeing all internal resources.
 251  *
 252  * The registered trace's reference count is decremented.
 253  *
 254  * @param msg_iter              CTF message iterator
 255  */
 256 BT_HIDDEN
 257 void ctf_msg_iter_destroy(struct ctf_msg_iter *msg_iter);
 258
 259 /**
 260  * Returns the next message from a CTF message iterator.
 261  *
 262  * Upon successful completion, #CTF_MSG_ITER_STATUS_OK is
 263  * returned, and the next message is written to \p msg.
 264  * In this case, the caller is responsible for calling
 265  * bt_message_put() on the returned message.
 266  *
 267  * If this function returns #CTF_MSG_ITER_STATUS_AGAIN, the caller
 268  * should make sure that data becomes available to its medium, and
 269  * call this function again, until another status is returned.
 270  *
 271  * @param msg_iter              CTF message iterator
 272  * @param message               Returned message if the function's
 273  *                              return value is #CTF_MSG_ITER_STATUS_OK
 274  * @returns                     One of #ctf_msg_iter_status values
 275  */
 276 BT_HIDDEN
 277 enum ctf_msg_iter_status ctf_msg_iter_get_next_message(
 278                 struct ctf_msg_iter *msg_it,
 279                 const bt_message **message);
 280
 281 struct ctf_msg_iter_packet_properties {
 282         int64_t exp_packet_total_size;
 283         int64_t exp_packet_content_size;
 284         uint64_t stream_class_id;
 285         int64_t data_stream_id;
 286
 287         struct {
 288                 uint64_t discarded_events;
 289                 uint64_t packets;
 290                 uint64_t beginning_clock;
 291                 uint64_t end_clock;
 292         } snapshots;
 293 };
 294
 295 BT_HIDDEN
 296 enum ctf_msg_iter_status ctf_msg_iter_get_packet_properties(
 297                 struct ctf_msg_iter *msg_it,
 298                 struct ctf_msg_iter_packet_properties *props);
 299
 300 BT_HIDDEN
 301 enum ctf_msg_iter_status ctf_msg_iter_curr_packet_first_event_clock_snapshot(
 302                 struct ctf_msg_iter *msg_it, uint64_t *first_event_cs);
 303
 304 BT_HIDDEN
 305 enum ctf_msg_iter_status ctf_msg_iter_curr_packet_last_event_clock_snapshot(
 306                 struct ctf_msg_iter *msg_it, uint64_t *last_event_cs);
 307
 308 BT_HIDDEN
 309 void ctf_msg_iter_set_medops_data(struct ctf_msg_iter *msg_it,
 310                 void *medops_data);
 311
 312 BT_HIDDEN
 313 enum ctf_msg_iter_status ctf_msg_iter_seek(
 314                 struct ctf_msg_iter *msg_it, off_t offset);
 315
 316 /*
 317  * Resets the iterator so that the next requested medium bytes are
 318  * assumed to be the first bytes of a new stream. Depending on
 319  * ctf_msg_iter_set_emit_stream_beginning_message(), the first message
 320  * which this iterator emits after calling ctf_msg_iter_reset() is of
 321  * type `CTF_MESSAGE_TYPE_STREAM_BEGINNING`.
 322  */
 323 BT_HIDDEN
 324 void ctf_msg_iter_reset(struct ctf_msg_iter *msg_it);
 325
 326 /*
 327  * Like ctf_msg_iter_reset(), but preserves stream-dependent state.
 328  */
 329 BT_HIDDEN
 330 void ctf_msg_iter_reset_for_next_stream_file(struct ctf_msg_iter *msg_it);
 331
 332 BT_HIDDEN
 333 void ctf_msg_iter_set_emit_stream_beginning_message(struct ctf_msg_iter *msg_it,
 334                 bool val);
 335
 336 BT_HIDDEN
 337 void ctf_msg_iter_set_emit_stream_end_message(struct ctf_msg_iter *msg_it,
 338                 bool val);
 339
 340 BT_HIDDEN
 341 void ctf_msg_iter_set_dry_run(struct ctf_msg_iter *msg_it,
 342                 bool val);
 343
 344 static inline
 345 const char *ctf_msg_iter_medium_status_string(
 346                 enum ctf_msg_iter_medium_status status)
 347 {
 348         switch (status) {
 349         case CTF_MSG_ITER_MEDIUM_STATUS_EOF:
 350                 return "EOF";
 351         case CTF_MSG_ITER_MEDIUM_STATUS_AGAIN:
 352                 return "AGAIN";
 353         case CTF_MSG_ITER_MEDIUM_STATUS_INVAL:
 354                 return "INVAL";
 355         case CTF_MSG_ITER_MEDIUM_STATUS_ERROR:
 356                 return "ERROR";
 357         case CTF_MSG_ITER_MEDIUM_STATUS_OK:
 358                 return "OK";
 359         default:
 360                 return "(unknown)";
 361         }
 362 }
 363
 364 static inline
 365 const char *ctf_msg_iter_status_string(
 366                 enum ctf_msg_iter_status status)
 367 {
 368         switch (status) {
 369         case CTF_MSG_ITER_STATUS_EOF:
 370                 return "EOF";
 371         case CTF_MSG_ITER_STATUS_AGAIN:
 372                 return "AGAIN";
 373         case CTF_MSG_ITER_STATUS_INVAL:
 374                 return "INVAL";
 375         case CTF_MSG_ITER_STATUS_ERROR:
 376                 return "ERROR";
 377         case CTF_MSG_ITER_STATUS_OK:
 378                 return "OK";
 379         default:
 380                 return "(unknown)";
 381         }
 382 }
 383
 384 #endif /* CTF_MSG_ITER_H */