plugins/ctf/common/notif-iter/notif-iter.h

   1 #ifndef CTF_NOTIF_ITER_H
   2 #define CTF_NOTIF_ITER_H
   3
   4 /*
   5  * Babeltrace - CTF notification 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 <stdint.h>
  30 #include <stdio.h>
  31 #include <stddef.h>
  32 #include <babeltrace/babeltrace.h>
  33 #include <babeltrace/babeltrace-internal.h>
  34
  35 /**
  36  * @file ctf-notif-iter.h
  37  *
  38  * CTF notification iterator
  39  *     ¯¯¯¯¯        ¯¯¯¯
  40  * This is a common internal API used by CTF source plugins. It allows
  41  * one to get notifications from a user-provided medium.
  42  */
  43
  44 /**
  45  * Medium operations status codes.
  46  */
  47 enum bt_notif_iter_medium_status {
  48         /**
  49          * End of file.
  50          *
  51          * The medium function called by the notification iterator
  52          * function reached the end of the file.
  53          */
  54         BT_NOTIF_ITER_MEDIUM_STATUS_EOF = 1,
  55
  56         /**
  57          * There is no data available right now, try again later.
  58          */
  59         BT_NOTIF_ITER_MEDIUM_STATUS_AGAIN = 11,
  60
  61         /** Unsupported operation. */
  62         BT_NOTIF_ITER_MEDIUM_STATUS_UNSUPPORTED = -3,
  63
  64         /** Invalid argument. */
  65         BT_NOTIF_ITER_MEDIUM_STATUS_INVAL = -2,
  66
  67         /** General error. */
  68         BT_NOTIF_ITER_MEDIUM_STATUS_ERROR = -1,
  69
  70         /** Everything okay. */
  71         BT_NOTIF_ITER_MEDIUM_STATUS_OK = 0,
  72 };
  73
  74 /**
  75  * CTF notification iterator API status code.
  76  */
  77 enum bt_notif_iter_status {
  78         /**
  79          * End of file.
  80          *
  81          * The medium function called by the notification iterator
  82          * function reached the end of the file.
  83          */
  84         BT_NOTIF_ITER_STATUS_EOF = BT_NOTIF_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          * bt_notif_iter_medium_ops::request_bytes() user function not
  91          * having access to any data now. You should retry calling the
  92          * last called notification iterator function once the situation
  93          * is resolved.
  94          */
  95         BT_NOTIF_ITER_STATUS_AGAIN = BT_NOTIF_ITER_MEDIUM_STATUS_AGAIN,
  96
  97         /** Invalid argument. */
  98         BT_NOTIF_ITER_STATUS_INVAL = BT_NOTIF_ITER_MEDIUM_STATUS_INVAL,
  99
 100         /** Unsupported operation. */
 101         BT_NOTIF_ITER_STATUS_UNSUPPORTED = BT_NOTIF_ITER_MEDIUM_STATUS_UNSUPPORTED,
 102
 103         /** General error. */
 104         BT_NOTIF_ITER_STATUS_ERROR = BT_NOTIF_ITER_MEDIUM_STATUS_ERROR,
 105
 106         /** Everything okay. */
 107         BT_NOTIF_ITER_STATUS_OK =       0,
 108 };
 109
 110 /**
 111  * CTF notification iterator seek operation directives.
 112  */
 113 enum bt_notif_iter_seek_whence {
 114         /**
 115          * Set the iterator's position to an absolute offset in the underlying
 116          * medium.
 117          */
 118         BT_NOTIF_ITER_SEEK_WHENCE_SET,
 119 };
 120
 121 /**
 122  * Medium operations.
 123  *
 124  * Those user functions are called by the notification iterator
 125  * functions to request medium actions.
 126  */
 127 struct bt_notif_iter_medium_ops {
 128         /**
 129          * Returns the next byte buffer to be used by the binary file
 130          * reader to deserialize binary data.
 131          *
 132          * This function \em must be defined.
 133          *
 134          * The purpose of this function is to return a buffer of bytes
 135          * to the notification iterator, of a maximum of \p request_sz
 136          * bytes. If this function cannot return a buffer of at least
 137          * \p request_sz bytes, it may return a smaller buffer. In
 138          * either cases, \p buffer_sz must be set to the returned buffer
 139          * size (in bytes).
 140          *
 141          * The returned buffer's ownership remains the medium, in that
 142          * it won't be freed by the notification iterator functions. The
 143          * returned buffer won't be modified by the notification
 144          * iterator functions either.
 145          *
 146          * When this function is called for the first time for a given
 147          * file, the offset within the file is considered to be 0. The
 148          * next times this function is called, the returned buffer's
 149          * byte offset within the complete file must be the previous
 150          * offset plus the last returned value of \p buffer_sz by this
 151          * medium.
 152          *
 153          * This function must return one of the following statuses:
 154          *
 155          *   - <b>#BT_NOTIF_ITER_MEDIUM_STATUS_OK</b>: Everything
 156          *     is okay, i.e. \p buffer_sz is set to a positive value
 157          *     reflecting the number of available bytes in the buffer
 158          *     starting at the address written in \p buffer_addr.
 159          *   - <b>#BT_NOTIF_ITER_MEDIUM_STATUS_AGAIN</b>: No data is
 160          *     available right now. In this case, the notification
 161          *     iterator function called by the user returns
 162          *     #BT_NOTIF_ITER_STATUS_AGAIN, and it is the user's
 163          *     responsibility to make sure enough data becomes available
 164          *     before calling the \em same notification iterator
 165          *     function again to continue the decoding process.
 166          *   - <b>#BT_NOTIF_ITER_MEDIUM_STATUS_EOF</b>: The end of
 167          *     the file was reached, and no more data will ever be
 168          *     available for this file. In this case, the notification
 169          *     iterator function called by the user returns
 170          *     #BT_NOTIF_ITER_STATUS_EOF. This must \em not be
 171          *     returned when returning at least one byte of data to the
 172          *     caller, i.e. this must be returned when there's
 173          *     absolutely nothing left; should the request size be
 174          *     larger than what's left in the file, this function must
 175          *     return what's left, setting \p buffer_sz to the number of
 176          *     remaining bytes, and return
 177          *     #BT_NOTIF_ITER_MEDIUM_STATUS_EOF on the \em following
 178          *     call.
 179          *   - <b>#BT_NOTIF_ITER_MEDIUM_STATUS_ERROR</b>: A fatal
 180          *     error occured during this operation. In this case, the
 181          *     notification iterator function called by the user returns
 182          *     #BT_NOTIF_ITER_STATUS_ERROR.
 183          *
 184          * If #BT_NOTIF_ITER_MEDIUM_STATUS_OK is not returned, the
 185          * values of \p buffer_sz and \p buffer_addr are \em ignored by
 186          * the caller.
 187          *
 188          * @param request_sz    Requested buffer size (bytes)
 189          * @param buffer_addr   Returned buffer address
 190          * @param buffer_sz     Returned buffer's size (bytes)
 191          * @param data          User data
 192          * @returns             Status code (see description above)
 193          */
 194         enum bt_notif_iter_medium_status (* request_bytes)(
 195                         size_t request_sz, uint8_t **buffer_addr,
 196                         size_t *buffer_sz, void *data);
 197
 198         /**
 199          * Repositions the underlying stream's position.
 200          *
 201          * This *optional* method repositions the underlying stream
 202          * to a given absolute or relative position, as indicated by
 203          * the whence directive.
 204          *
 205          * @param whence        One of #bt_notif_iter_seek_whence values
 206          * @param offset        Offset to use for the given directive
 207          * @param data          User data
 208          * @returns             One of #bt_notif_iter_medium_status values
 209          */
 210         enum bt_notif_iter_medium_status (* seek)(
 211                         enum bt_notif_iter_seek_whence whence,
 212                         off_t offset, void *data);
 213
 214         /**
 215          * Returns a stream instance (weak reference) for the given
 216          * stream class.
 217          *
 218          * This is called after a packet header is read, and the
 219          * corresponding stream class is found by the notification
 220          * iterator.
 221          *
 222          * @param stream_class  Stream class of the stream to get
 223          * @param stream_id     Stream (instance) ID of the stream
 224          *                      to get (-1ULL if not available)
 225          * @param data          User data
 226          * @returns             Stream instance (weak reference) or
 227          *                      \c NULL on error
 228          */
 229         struct bt_stream * (* borrow_stream)(
 230                         struct bt_stream_class *stream_class,
 231                         uint64_t stream_id, void *data);
 232 };
 233
 234 /** CTF notification iterator. */
 235 struct bt_notif_iter;
 236
 237 // TODO: Replace by the real thing
 238 enum bt_notif_iter_notif_type {
 239         BT_NOTIF_ITER_NOTIF_NEW_PACKET,
 240         BT_NOTIF_ITER_NOTIF_END_OF_PACKET,
 241         BT_NOTIF_ITER_NOTIF_EVENT,
 242 };
 243
 244 struct bt_notif_iter_notif {
 245         enum bt_notif_iter_notif_type type;
 246 };
 247
 248 struct bt_notif_iter_notif_new_packet {
 249         struct bt_notif_iter_notif base;
 250         struct bt_packet *packet;
 251 };
 252
 253 struct bt_notif_iter_notif_end_of_packet {
 254         struct bt_notif_iter_notif base;
 255         struct bt_packet *packet;
 256 };
 257
 258 struct bt_notif_iter_notif_event {
 259         struct bt_notif_iter_notif base;
 260         struct bt_event *event;
 261 };
 262
 263 /**
 264  * Creates a CTF notification iterator.
 265  *
 266  * Upon successful completion, the reference count of \p trace is
 267  * incremented.
 268  *
 269  * @param trace                 Trace to read
 270  * @param max_request_sz        Maximum buffer size, in bytes, to
 271  *                              request to
 272  *                              bt_notif_iter_medium_ops::request_bytes()
 273  *                              at a time
 274  * @param medops                Medium operations
 275  * @param medops_data           User data (passed to medium operations)
 276  * @returns                     New CTF notification iterator on
 277  *                              success, or \c NULL on error
 278  */
 279 BT_HIDDEN
 280 struct bt_notif_iter *bt_notif_iter_create(struct bt_trace *trace,
 281         size_t max_request_sz, struct bt_notif_iter_medium_ops medops,
 282         void *medops_data);
 283
 284 /**
 285  * Destroys a CTF notification iterator, freeing all internal resources.
 286  *
 287  * The registered trace's reference count is decremented.
 288  *
 289  * @param notif_iter            CTF notification iterator
 290  */
 291 BT_HIDDEN
 292 void bt_notif_iter_destroy(struct bt_notif_iter *notif_iter);
 293
 294 /**
 295  * Returns the next notification from a CTF notification iterator.
 296  *
 297  * Upon successful completion, #BT_NOTIF_ITER_STATUS_OK is
 298  * returned, and the next notification is written to \p notif.
 299  * In this case, the caller is responsible for calling
 300  * bt_notification_put() on the returned notification.
 301  *
 302  * If this function returns #BT_NOTIF_ITER_STATUS_AGAIN, the caller
 303  * should make sure that data becomes available to its medium, and
 304  * call this function again, until another status is returned.
 305  *
 306  * @param notif_iter            CTF notification iterator
 307  * @param cc_prio_map           Clock class priority map to use when
 308  *                              creating an event notification
 309  * @param notification          Returned notification if the function's
 310  *                              return value is #BT_NOTIF_ITER_STATUS_OK
 311  * @returns                     One of #bt_notif_iter_status values
 312  */
 313 BT_HIDDEN
 314 enum bt_notif_iter_status bt_notif_iter_get_next_notification(
 315                 struct bt_notif_iter *notit,
 316                 struct bt_clock_class_priority_map *cc_prio_map,
 317                 struct bt_notification **notification);
 318
 319 /**
 320  * Returns the first packet header and context fields. This function
 321  * never needs to call the `borrow_stream()` medium operation because
 322  * it does not create packet or event objects.
 323  *
 324  * @param notif_iter            CTF notification iterator
 325  * @param packet_header_field   Packet header field (\c NULL if there's
 326  *                              no packet header field)
 327  * @param packet_context_field  Packet context field (\c NULL if there's
 328  *                              no packet context field)
 329  * @returns                     One of #bt_notif_iter_status values
 330  */
 331 BT_HIDDEN
 332 enum bt_notif_iter_status bt_notif_iter_borrow_packet_header_context_fields(
 333                 struct bt_notif_iter *notit,
 334                 struct bt_field **packet_header_field,
 335                 struct bt_field **packet_context_field);
 336
 337 BT_HIDDEN
 338 void bt_notif_iter_set_medops_data(struct bt_notif_iter *notit,
 339                 void *medops_data);
 340
 341 BT_HIDDEN
 342 enum bt_notif_iter_status bt_notif_iter_seek(
 343                 struct bt_notif_iter *notit, off_t offset);
 344
 345 /*
 346  * Get the current packet's offset in bytes relative to the media's initial
 347  * position.
 348  */
 349 BT_HIDDEN
 350 off_t bt_notif_iter_get_current_packet_offset(
 351                 struct bt_notif_iter *notit);
 352
 353 /* Get the current packet's size (in bits). */
 354 BT_HIDDEN
 355 off_t bt_notif_iter_get_current_packet_size(
 356                 struct bt_notif_iter *notit);
 357
 358 /*
 359  * Resets the iterator so that the next requested medium bytes are
 360  * assumed to be the first bytes of a new stream. The first notification
 361  * which this iterator emits after calling bt_notif_iter_reset() is a
 362  * BT_NOTIFICATION_TYPE_STREAM_BEGIN one.
 363  */
 364 BT_HIDDEN
 365 void bt_notif_iter_reset(struct bt_notif_iter *notit);
 366
 367 static inline
 368 const char *bt_notif_iter_medium_status_string(
 369                 enum bt_notif_iter_medium_status status)
 370 {
 371         switch (status) {
 372         case BT_NOTIF_ITER_MEDIUM_STATUS_EOF:
 373                 return "BT_NOTIF_ITER_MEDIUM_STATUS_EOF";
 374         case BT_NOTIF_ITER_MEDIUM_STATUS_AGAIN:
 375                 return "BT_NOTIF_ITER_MEDIUM_STATUS_AGAIN";
 376         case BT_NOTIF_ITER_MEDIUM_STATUS_INVAL:
 377                 return "BT_NOTIF_ITER_MEDIUM_STATUS_INVAL";
 378         case BT_NOTIF_ITER_MEDIUM_STATUS_ERROR:
 379                 return "BT_NOTIF_ITER_MEDIUM_STATUS_ERROR";
 380         case BT_NOTIF_ITER_MEDIUM_STATUS_OK:
 381                 return "BT_NOTIF_ITER_MEDIUM_STATUS_OK";
 382         default:
 383                 return "(unknown)";
 384         }
 385 }
 386
 387 static inline
 388 const char *bt_notif_iter_status_string(
 389                 enum bt_notif_iter_status status)
 390 {
 391         switch (status) {
 392         case BT_NOTIF_ITER_STATUS_EOF:
 393                 return "BT_NOTIF_ITER_STATUS_EOF";
 394         case BT_NOTIF_ITER_STATUS_AGAIN:
 395                 return "BT_NOTIF_ITER_STATUS_AGAIN";
 396         case BT_NOTIF_ITER_STATUS_INVAL:
 397                 return "BT_NOTIF_ITER_STATUS_INVAL";
 398         case BT_NOTIF_ITER_STATUS_ERROR:
 399                 return "BT_NOTIF_ITER_STATUS_ERROR";
 400         case BT_NOTIF_ITER_STATUS_OK:
 401                 return "BT_NOTIF_ITER_STATUS_OK";
 402         default:
 403                 return "(unknown)";
 404         }
 405 }
 406
 407 #endif /* CTF_NOTIF_ITER_H */