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.  These use the same values as
  49  * libbabeltrace2.
  50  */
  51 enum ctf_msg_iter_medium_status {
  52         /**
  53          * End of file.
  54          *
  55          * The medium function called by the message iterator
  56          * function reached the end of the file.
  57          */
  58         CTF_MSG_ITER_MEDIUM_STATUS_EOF = 1,
  59
  60         /**
  61          * There is no data available right now, try again later.
  62          */
  63         CTF_MSG_ITER_MEDIUM_STATUS_AGAIN = 11,
  64
  65         /** General error. */
  66         CTF_MSG_ITER_MEDIUM_STATUS_ERROR = -1,
  67
  68         /** Memory error. */
  69         CTF_MSG_ITER_MEDIUM_STATUS_MEMORY_ERROR = -12,
  70
  71         /** Everything okay. */
  72         CTF_MSG_ITER_MEDIUM_STATUS_OK = 0,
  73 };
  74
  75 /**
  76  * CTF message iterator API status code.
  77  */
  78 enum ctf_msg_iter_status {
  79         /**
  80          * End of file.
  81          *
  82          * The medium function called by the message iterator
  83          * function reached the end of the file.
  84          */
  85         CTF_MSG_ITER_STATUS_EOF = CTF_MSG_ITER_MEDIUM_STATUS_EOF,
  86
  87         /**
  88          * There is no data available right now, try again later.
  89          *
  90          * Some condition resulted in the
  91          * ctf_msg_iter_medium_ops::request_bytes() user function not
  92          * having access to any data now. You should retry calling the
  93          * last called message iterator function once the situation
  94          * is resolved.
  95          */
  96         CTF_MSG_ITER_STATUS_AGAIN = CTF_MSG_ITER_MEDIUM_STATUS_AGAIN,
  97
  98         /** General error. */
  99         CTF_MSG_ITER_STATUS_ERROR = CTF_MSG_ITER_MEDIUM_STATUS_ERROR,
 100
 101         /** Memory error. */
 102         CTF_MSG_ITER_STATUS_MEMORY_ERROR  = CTF_MSG_ITER_MEDIUM_STATUS_MEMORY_ERROR,
 103
 104         /** Everything okay. */
 105         CTF_MSG_ITER_STATUS_OK = CTF_MSG_ITER_MEDIUM_STATUS_OK,
 106 };
 107
 108 /**
 109  * Medium operations.
 110  *
 111  * Those user functions are called by the message iterator
 112  * functions to request medium actions.
 113  */
 114 struct ctf_msg_iter_medium_ops {
 115         /**
 116          * Returns the next byte buffer to be used by the binary file
 117          * reader to deserialize binary data.
 118          *
 119          * This function \em must be defined.
 120          *
 121          * The purpose of this function is to return a buffer of bytes
 122          * to the message iterator, of a maximum of \p request_sz
 123          * bytes. If this function cannot return a buffer of at least
 124          * \p request_sz bytes, it may return a smaller buffer. In
 125          * either cases, \p buffer_sz must be set to the returned buffer
 126          * size (in bytes).
 127          *
 128          * The returned buffer's ownership remains the medium, in that
 129          * it won't be freed by the message iterator functions. The
 130          * returned buffer won't be modified by the message
 131          * iterator functions either.
 132          *
 133          * When this function is called for the first time for a given
 134          * file, the offset within the file is considered to be 0. The
 135          * next times this function is called, the returned buffer's
 136          * byte offset within the complete file must be the previous
 137          * offset plus the last returned value of \p buffer_sz by this
 138          * medium.
 139          *
 140          * This function must return one of the following statuses:
 141          *
 142          *   - <b>#CTF_MSG_ITER_MEDIUM_STATUS_OK</b>: Everything
 143          *     is okay, i.e. \p buffer_sz is set to a positive value
 144          *     reflecting the number of available bytes in the buffer
 145          *     starting at the address written in \p buffer_addr.
 146          *   - <b>#CTF_MSG_ITER_MEDIUM_STATUS_AGAIN</b>: No data is
 147          *     available right now. In this case, the message
 148          *     iterator function called by the user returns
 149          *     #CTF_MSG_ITER_STATUS_AGAIN, and it is the user's
 150          *     responsibility to make sure enough data becomes available
 151          *     before calling the \em same message iterator
 152          *     function again to continue the decoding process.
 153          *   - <b>#CTF_MSG_ITER_MEDIUM_STATUS_EOF</b>: The end of
 154          *     the file was reached, and no more data will ever be
 155          *     available for this file. In this case, the message
 156          *     iterator function called by the user returns
 157          *     #CTF_MSG_ITER_STATUS_EOF. This must \em not be
 158          *     returned when returning at least one byte of data to the
 159          *     caller, i.e. this must be returned when there's
 160          *     absolutely nothing left; should the request size be
 161          *     larger than what's left in the file, this function must
 162          *     return what's left, setting \p buffer_sz to the number of
 163          *     remaining bytes, and return
 164          *     #CTF_MSG_ITER_MEDIUM_STATUS_EOF on the \em following
 165          *     call.
 166          *   - <b>#CTF_MSG_ITER_MEDIUM_STATUS_ERROR</b>: A fatal
 167          *     error occured during this operation. In this case, the
 168          *     message iterator function called by the user returns
 169          *     #CTF_MSG_ITER_STATUS_ERROR.
 170          *
 171          * If #CTF_MSG_ITER_MEDIUM_STATUS_OK is not returned, the
 172          * values of \p buffer_sz and \p buffer_addr are \em ignored by
 173          * the caller.
 174          *
 175          * @param request_sz    Requested buffer size (bytes)
 176          * @param buffer_addr   Returned buffer address
 177          * @param buffer_sz     Returned buffer's size (bytes)
 178          * @param data          User data
 179          * @returns             Status code (see description above)
 180          */
 181         enum ctf_msg_iter_medium_status (* request_bytes)(size_t request_sz,
 182                         uint8_t **buffer_addr, size_t *buffer_sz, void *data);
 183
 184         /**
 185          * Repositions the underlying stream's position.
 186          *
 187          * This *optional* method repositions the underlying stream
 188          * to a given absolute position in the medium.
 189          *
 190          * @param offset        Offset to use for the given directive
 191          * @param data          User data
 192          * @returns             One of #ctf_msg_iter_medium_status values
 193          */
 194         enum ctf_msg_iter_medium_status (* seek)(off_t offset, void *data);
 195
 196         /**
 197          * Called when the message iterator wishes to inform the medium that it
 198          * is about to start a new packet.
 199          *
 200          * After the iterator has called switch_packet, the following call to
 201          * request_bytes must return the content at the start of the next
 202          * packet.       */
 203         enum ctf_msg_iter_medium_status (* switch_packet)(void *data);
 204
 205         /**
 206          * Returns a stream instance (weak reference) for the given
 207          * stream class.
 208          *
 209          * This is called after a packet header is read, and the
 210          * corresponding stream class is found by the message
 211          * iterator.
 212          *
 213          * @param stream_class  Stream class of the stream to get
 214          * @param stream_id     Stream (instance) ID of the stream
 215          *                      to get (-1ULL if not available)
 216          * @param data          User data
 217          * @returns             Stream instance (weak reference) or
 218          *                      \c NULL on error
 219          */
 220         bt_stream * (* borrow_stream)(bt_stream_class *stream_class,
 221                         int64_t stream_id, void *data);
 222 };
 223
 224 /** CTF message iterator. */
 225 struct ctf_msg_iter;
 226
 227 /**
 228  * Creates a CTF message iterator.
 229  *
 230  * Upon successful completion, the reference count of \p trace is
 231  * incremented.
 232  *
 233  * @param trace                 Trace to read
 234  * @param max_request_sz        Maximum buffer size, in bytes, to
 235  *                              request to
 236  *                              ctf_msg_iter_medium_ops::request_bytes()
 237  *                              at a time
 238  * @param medops                Medium operations
 239  * @param medops_data           User data (passed to medium operations)
 240  * @returns                     New CTF message iterator on
 241  *                              success, or \c NULL on error
 242  */
 243 BT_HIDDEN
 244 struct ctf_msg_iter *ctf_msg_iter_create(
 245                 struct ctf_trace_class *tc,
 246                 size_t max_request_sz,
 247                 struct ctf_msg_iter_medium_ops medops,
 248                 void *medops_data,
 249                 bt_logging_level log_level,
 250                 bt_self_component *self_comp,
 251                 bt_self_message_iterator *self_msg_iter);
 252
 253 /**
 254  * Destroys a CTF message iterator, freeing all internal resources.
 255  *
 256  * The registered trace's reference count is decremented.
 257  *
 258  * @param msg_iter              CTF message iterator
 259  */
 260 BT_HIDDEN
 261 void ctf_msg_iter_destroy(struct ctf_msg_iter *msg_iter);
 262
 263 /**
 264  * Returns the next message from a CTF message iterator.
 265  *
 266  * Upon successful completion, #CTF_MSG_ITER_STATUS_OK is
 267  * returned, and the next message is written to \p msg.
 268  * In this case, the caller is responsible for calling
 269  * bt_message_put() on the returned message.
 270  *
 271  * If this function returns #CTF_MSG_ITER_STATUS_AGAIN, the caller
 272  * should make sure that data becomes available to its medium, and
 273  * call this function again, until another status is returned.
 274  *
 275  * @param msg_iter              CTF message iterator
 276  * @param message               Returned message if the function's
 277  *                              return value is #CTF_MSG_ITER_STATUS_OK
 278  * @returns                     One of #ctf_msg_iter_status values
 279  */
 280 BT_HIDDEN
 281 enum ctf_msg_iter_status ctf_msg_iter_get_next_message(
 282                 struct ctf_msg_iter *msg_it,
 283                 const bt_message **message);
 284
 285 struct ctf_msg_iter_packet_properties {
 286         int64_t exp_packet_total_size;
 287         int64_t exp_packet_content_size;
 288         uint64_t stream_class_id;
 289         int64_t data_stream_id;
 290
 291         struct {
 292                 uint64_t discarded_events;
 293                 uint64_t packets;
 294                 uint64_t beginning_clock;
 295                 uint64_t end_clock;
 296         } snapshots;
 297 };
 298
 299 BT_HIDDEN
 300 enum ctf_msg_iter_status ctf_msg_iter_get_packet_properties(
 301                 struct ctf_msg_iter *msg_it,
 302                 struct ctf_msg_iter_packet_properties *props);
 303
 304 BT_HIDDEN
 305 enum ctf_msg_iter_status ctf_msg_iter_curr_packet_first_event_clock_snapshot(
 306                 struct ctf_msg_iter *msg_it, uint64_t *first_event_cs);
 307
 308 BT_HIDDEN
 309 enum ctf_msg_iter_status ctf_msg_iter_curr_packet_last_event_clock_snapshot(
 310                 struct ctf_msg_iter *msg_it, uint64_t *last_event_cs);
 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_dry_run(struct ctf_msg_iter *msg_it,
 334                 bool val);
 335
 336 static inline
 337 const char *ctf_msg_iter_medium_status_string(
 338                 enum ctf_msg_iter_medium_status status)
 339 {
 340         switch (status) {
 341         case CTF_MSG_ITER_MEDIUM_STATUS_EOF:
 342                 return "EOF";
 343         case CTF_MSG_ITER_MEDIUM_STATUS_AGAIN:
 344                 return "AGAIN";
 345         case CTF_MSG_ITER_MEDIUM_STATUS_ERROR:
 346                 return "ERROR";
 347         case CTF_MSG_ITER_MEDIUM_STATUS_OK:
 348                 return "OK";
 349         default:
 350                 return "(unknown)";
 351         }
 352 }
 353
 354 static inline
 355 const char *ctf_msg_iter_status_string(
 356                 enum ctf_msg_iter_status status)
 357 {
 358         switch (status) {
 359         case CTF_MSG_ITER_STATUS_EOF:
 360                 return "EOF";
 361         case CTF_MSG_ITER_STATUS_AGAIN:
 362                 return "AGAIN";
 363         case CTF_MSG_ITER_STATUS_ERROR:
 364                 return "ERROR";
 365         case CTF_MSG_ITER_STATUS_OK:
 366                 return "OK";
 367         default:
 368                 return "(unknown)";
 369         }
 370 }
 371
 372 #endif /* CTF_MSG_ITER_H */