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 bt_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         BT_MSG_ITER_MEDIUM_STATUS_EOF = 1,
  58
  59         /**
  60          * There is no data available right now, try again later.
  61          */
  62         BT_MSG_ITER_MEDIUM_STATUS_AGAIN = 11,
  63
  64         /** Unsupported operation. */
  65         BT_MSG_ITER_MEDIUM_STATUS_UNSUPPORTED = -3,
  66
  67         /** Invalid argument. */
  68         BT_MSG_ITER_MEDIUM_STATUS_INVAL = -2,
  69
  70         /** General error. */
  71         BT_MSG_ITER_MEDIUM_STATUS_ERROR = -1,
  72
  73         /** Everything okay. */
  74         BT_MSG_ITER_MEDIUM_STATUS_OK = 0,
  75 };
  76
  77 /**
  78  * CTF message iterator API status code.
  79  */
  80 enum bt_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         BT_MSG_ITER_STATUS_EOF = BT_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          * bt_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         BT_MSG_ITER_STATUS_AGAIN = BT_MSG_ITER_MEDIUM_STATUS_AGAIN,
  99
 100         /** Invalid argument. */
 101         BT_MSG_ITER_STATUS_INVAL = BT_MSG_ITER_MEDIUM_STATUS_INVAL,
 102
 103         /** Unsupported operation. */
 104         BT_MSG_ITER_STATUS_UNSUPPORTED = BT_MSG_ITER_MEDIUM_STATUS_UNSUPPORTED,
 105
 106         /** General error. */
 107         BT_MSG_ITER_STATUS_ERROR = BT_MSG_ITER_MEDIUM_STATUS_ERROR,
 108
 109         /** Everything okay. */
 110         BT_MSG_ITER_STATUS_OK = 0,
 111 };
 112
 113 /**
 114  * CTF message iterator seek operation directives.
 115  */
 116 enum bt_msg_iter_seek_whence {
 117         /**
 118          * Set the iterator's position to an absolute offset in the underlying
 119          * medium.
 120          */
 121         BT_MSG_ITER_SEEK_WHENCE_SET,
 122 };
 123
 124 /**
 125  * Medium operations.
 126  *
 127  * Those user functions are called by the message iterator
 128  * functions to request medium actions.
 129  */
 130 struct bt_msg_iter_medium_ops {
 131         /**
 132          * Returns the next byte buffer to be used by the binary file
 133          * reader to deserialize binary data.
 134          *
 135          * This function \em must be defined.
 136          *
 137          * The purpose of this function is to return a buffer of bytes
 138          * to the message iterator, of a maximum of \p request_sz
 139          * bytes. If this function cannot return a buffer of at least
 140          * \p request_sz bytes, it may return a smaller buffer. In
 141          * either cases, \p buffer_sz must be set to the returned buffer
 142          * size (in bytes).
 143          *
 144          * The returned buffer's ownership remains the medium, in that
 145          * it won't be freed by the message iterator functions. The
 146          * returned buffer won't be modified by the message
 147          * iterator functions either.
 148          *
 149          * When this function is called for the first time for a given
 150          * file, the offset within the file is considered to be 0. The
 151          * next times this function is called, the returned buffer's
 152          * byte offset within the complete file must be the previous
 153          * offset plus the last returned value of \p buffer_sz by this
 154          * medium.
 155          *
 156          * This function must return one of the following statuses:
 157          *
 158          *   - <b>#BT_MSG_ITER_MEDIUM_STATUS_OK</b>: Everything
 159          *     is okay, i.e. \p buffer_sz is set to a positive value
 160          *     reflecting the number of available bytes in the buffer
 161          *     starting at the address written in \p buffer_addr.
 162          *   - <b>#BT_MSG_ITER_MEDIUM_STATUS_AGAIN</b>: No data is
 163          *     available right now. In this case, the message
 164          *     iterator function called by the user returns
 165          *     #BT_MSG_ITER_STATUS_AGAIN, and it is the user's
 166          *     responsibility to make sure enough data becomes available
 167          *     before calling the \em same message iterator
 168          *     function again to continue the decoding process.
 169          *   - <b>#BT_MSG_ITER_MEDIUM_STATUS_EOF</b>: The end of
 170          *     the file was reached, and no more data will ever be
 171          *     available for this file. In this case, the message
 172          *     iterator function called by the user returns
 173          *     #BT_MSG_ITER_STATUS_EOF. This must \em not be
 174          *     returned when returning at least one byte of data to the
 175          *     caller, i.e. this must be returned when there's
 176          *     absolutely nothing left; should the request size be
 177          *     larger than what's left in the file, this function must
 178          *     return what's left, setting \p buffer_sz to the number of
 179          *     remaining bytes, and return
 180          *     #BT_MSG_ITER_MEDIUM_STATUS_EOF on the \em following
 181          *     call.
 182          *   - <b>#BT_MSG_ITER_MEDIUM_STATUS_ERROR</b>: A fatal
 183          *     error occured during this operation. In this case, the
 184          *     message iterator function called by the user returns
 185          *     #BT_MSG_ITER_STATUS_ERROR.
 186          *
 187          * If #BT_MSG_ITER_MEDIUM_STATUS_OK is not returned, the
 188          * values of \p buffer_sz and \p buffer_addr are \em ignored by
 189          * the caller.
 190          *
 191          * @param request_sz    Requested buffer size (bytes)
 192          * @param buffer_addr   Returned buffer address
 193          * @param buffer_sz     Returned buffer's size (bytes)
 194          * @param data          User data
 195          * @returns             Status code (see description above)
 196          */
 197         enum bt_msg_iter_medium_status (* request_bytes)(size_t request_sz,
 198                         uint8_t **buffer_addr, size_t *buffer_sz, void *data);
 199
 200         /**
 201          * Repositions the underlying stream's position.
 202          *
 203          * This *optional* method repositions the underlying stream
 204          * to a given absolute or relative position, as indicated by
 205          * the whence directive.
 206          *
 207          * @param whence        One of #bt_msg_iter_seek_whence values
 208          * @param offset        Offset to use for the given directive
 209          * @param data          User data
 210          * @returns             One of #bt_msg_iter_medium_status values
 211          */
 212         enum bt_msg_iter_medium_status (* seek)(
 213                         enum bt_msg_iter_seek_whence whence,
 214                         off_t offset, void *data);
 215
 216         /**
 217          * Returns a stream instance (weak reference) for the given
 218          * stream class.
 219          *
 220          * This is called after a packet header is read, and the
 221          * corresponding stream class is found by the message
 222          * iterator.
 223          *
 224          * @param stream_class  Stream class of the stream to get
 225          * @param stream_id     Stream (instance) ID of the stream
 226          *                      to get (-1ULL if not available)
 227          * @param data          User data
 228          * @returns             Stream instance (weak reference) or
 229          *                      \c NULL on error
 230          */
 231         bt_stream * (* borrow_stream)(bt_stream_class *stream_class,
 232                         int64_t stream_id, void *data);
 233 };
 234
 235 /** CTF message iterator. */
 236 struct bt_msg_iter;
 237
 238 /**
 239  * Creates a CTF message iterator.
 240  *
 241  * Upon successful completion, the reference count of \p trace is
 242  * incremented.
 243  *
 244  * @param trace                 Trace to read
 245  * @param max_request_sz        Maximum buffer size, in bytes, to
 246  *                              request to
 247  *                              bt_msg_iter_medium_ops::request_bytes()
 248  *                              at a time
 249  * @param medops                Medium operations
 250  * @param medops_data           User data (passed to medium operations)
 251  * @returns                     New CTF message iterator on
 252  *                              success, or \c NULL on error
 253  */
 254 BT_HIDDEN
 255 struct bt_msg_iter *bt_msg_iter_create(struct ctf_trace_class *tc,
 256         size_t max_request_sz, struct bt_msg_iter_medium_ops medops,
 257         void *medops_data, bt_logging_level log_level,
 258         bt_self_component *self_comp);
 259
 260 /**
 261  * Destroys a CTF message iterator, freeing all internal resources.
 262  *
 263  * The registered trace's reference count is decremented.
 264  *
 265  * @param msg_iter              CTF message iterator
 266  */
 267 BT_HIDDEN
 268 void bt_msg_iter_destroy(struct bt_msg_iter *msg_iter);
 269
 270 /**
 271  * Returns the next message from a CTF message iterator.
 272  *
 273  * Upon successful completion, #BT_MSG_ITER_STATUS_OK is
 274  * returned, and the next message is written to \p msg.
 275  * In this case, the caller is responsible for calling
 276  * bt_message_put() on the returned message.
 277  *
 278  * If this function returns #BT_MSG_ITER_STATUS_AGAIN, the caller
 279  * should make sure that data becomes available to its medium, and
 280  * call this function again, until another status is returned.
 281  *
 282  * @param msg_iter              CTF message iterator
 283  * @param message               Returned message if the function's
 284  *                              return value is #BT_MSG_ITER_STATUS_OK
 285  * @returns                     One of #bt_msg_iter_status values
 286  */
 287 BT_HIDDEN
 288 enum bt_msg_iter_status bt_msg_iter_get_next_message(
 289                 struct bt_msg_iter *msg_it,
 290                 bt_self_message_iterator *msg_iter,
 291                 bt_message **message);
 292
 293 struct bt_msg_iter_packet_properties {
 294         int64_t exp_packet_total_size;
 295         int64_t exp_packet_content_size;
 296         uint64_t stream_class_id;
 297         int64_t data_stream_id;
 298
 299         struct {
 300                 uint64_t discarded_events;
 301                 uint64_t packets;
 302                 uint64_t beginning_clock;
 303                 uint64_t end_clock;
 304         } snapshots;
 305 };
 306
 307 BT_HIDDEN
 308 enum bt_msg_iter_status bt_msg_iter_get_packet_properties(
 309                 struct bt_msg_iter *msg_it,
 310                 struct bt_msg_iter_packet_properties *props);
 311
 312 BT_HIDDEN
 313 enum bt_msg_iter_status bt_msg_iter_curr_packet_first_event_clock_snapshot(
 314                 struct bt_msg_iter *msg_it, uint64_t *first_event_cs);
 315
 316 BT_HIDDEN
 317 enum bt_msg_iter_status bt_msg_iter_curr_packet_last_event_clock_snapshot(
 318                 struct bt_msg_iter *msg_it, uint64_t *last_event_cs);
 319
 320 BT_HIDDEN
 321 void bt_msg_iter_set_medops_data(struct bt_msg_iter *msg_it,
 322                 void *medops_data);
 323
 324 BT_HIDDEN
 325 enum bt_msg_iter_status bt_msg_iter_seek(
 326                 struct bt_msg_iter *msg_it, off_t offset);
 327
 328 /*
 329  * Resets the iterator so that the next requested medium bytes are
 330  * assumed to be the first bytes of a new stream. Depending on
 331  * bt_msg_iter_set_emit_stream_beginning_message(), the first message
 332  * which this iterator emits after calling bt_msg_iter_reset() is of
 333  * type `BT_MESSAGE_TYPE_STREAM_BEGINNING`.
 334  */
 335 BT_HIDDEN
 336 void bt_msg_iter_reset(struct bt_msg_iter *msg_it);
 337
 338 /*
 339  * Like bt_msg_iter_reset(), but preserves stream-dependent state.
 340  */
 341 BT_HIDDEN
 342 void bt_msg_iter_reset_for_next_stream_file(struct bt_msg_iter *msg_it);
 343
 344 BT_HIDDEN
 345 void bt_msg_iter_set_emit_stream_beginning_message(struct bt_msg_iter *msg_it,
 346                 bool val);
 347
 348 BT_HIDDEN
 349 void bt_msg_iter_set_emit_stream_end_message(struct bt_msg_iter *msg_it,
 350                 bool val);
 351
 352 BT_HIDDEN
 353 void bt_msg_iter_set_dry_run(struct bt_msg_iter *msg_it,
 354                 bool val);
 355
 356 static inline
 357 const char *bt_msg_iter_medium_status_string(
 358                 enum bt_msg_iter_medium_status status)
 359 {
 360         switch (status) {
 361         case BT_MSG_ITER_MEDIUM_STATUS_EOF:
 362                 return "EOF";
 363         case BT_MSG_ITER_MEDIUM_STATUS_AGAIN:
 364                 return "AGAIN";
 365         case BT_MSG_ITER_MEDIUM_STATUS_INVAL:
 366                 return "INVAL";
 367         case BT_MSG_ITER_MEDIUM_STATUS_ERROR:
 368                 return "ERROR";
 369         case BT_MSG_ITER_MEDIUM_STATUS_OK:
 370                 return "OK";
 371         default:
 372                 return "(unknown)";
 373         }
 374 }
 375
 376 static inline
 377 const char *bt_msg_iter_status_string(
 378                 enum bt_msg_iter_status status)
 379 {
 380         switch (status) {
 381         case BT_MSG_ITER_STATUS_EOF:
 382                 return "EOF";
 383         case BT_MSG_ITER_STATUS_AGAIN:
 384                 return "AGAIN";
 385         case BT_MSG_ITER_STATUS_INVAL:
 386                 return "INVAL";
 387         case BT_MSG_ITER_STATUS_ERROR:
 388                 return "ERROR";
 389         case BT_MSG_ITER_STATUS_OK:
 390                 return "OK";
 391         default:
 392                 return "(unknown)";
 393         }
 394 }
 395
 396 #endif /* CTF_MSG_ITER_H */