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