include/babeltrace/iterator.h

   1 #ifndef _BABELTRACE_ITERATOR_H
   2 #define _BABELTRACE_ITERATOR_H
   3
   4 /*
   5  * BabelTrace API Iterators
   6  *
   7  * Copyright 2010-2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  *
   9  * Permission is hereby granted, free of charge, to any person obtaining a copy
  10  * of this software and associated documentation files (the "Software"), to deal
  11  * in the Software without restriction, including without limitation the rights
  12  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  13  * copies of the Software, and to permit persons to whom the Software is
  14  * furnished to do so, subject to the following conditions:
  15  *
  16  * The above copyright notice and this permission notice shall be included in
  17  * all copies or substantial portions of the Software.
  18  */
  19
  20 #include <babeltrace/format.h>
  21 #include <babeltrace/context.h>
  22
  23 /* Forward declarations */
  24 struct bt_iter;
  25 struct bt_saved_pos;
  26
  27 struct bt_iter_pos {
  28         enum {
  29                 BT_SEEK_TIME,           /* uses u.seek_time */
  30                 BT_SEEK_RESTORE,        /* uses u.restore */
  31                 BT_SEEK_CUR,
  32                 BT_SEEK_BEGIN,
  33                 BT_SEEK_END,
  34         } type;
  35         union {
  36                 uint64_t seek_time;
  37                 struct bt_saved_pos *restore;
  38         } u;
  39 };
  40
  41 /*
  42  * bt_iter_next: Move trace collection position to the next event.
  43  *
  44  * Returns 0 on success, a negative value on error
  45  */
  46 int bt_iter_next(struct bt_iter *iter);
  47
  48 /*
  49  * bt_iter_get_pos - Get the current iterator position.
  50  *
  51  * The position returned by this function needs to be freed by
  52  * bt_iter_free_pos after use.
  53  */
  54 struct bt_iter_pos *bt_iter_get_pos(struct bt_iter *iter);
  55
  56 /*
  57  * bt_iter_free_pos - Free the position.
  58  */
  59 void bt_iter_free_pos(struct bt_iter_pos *pos);
  60
  61 /*
  62  * bt_iter_set_pos: move the iterator to a given position.
  63  *
  64  * On error, the stream_heap is reinitialized and returned empty.
  65  *
  66  * Return 0 for success.
  67  *
  68  * Return EOF if the position requested is after the last event of the
  69  * trace collection.
  70  * Return -EINVAL when called with invalid parameter.
  71  * Return -ENOMEM if the stream_heap could not be properly initialized.
  72  */
  73 int bt_iter_set_pos(struct bt_iter *iter, const struct bt_iter_pos *pos);
  74
  75 /*
  76  * bt_iter_create_time_pos: create a position based on time
  77  *
  78  * This function allocates and returns a new bt_iter_pos (which must be freed
  79  * with bt_iter_free_pos) to be able to restore an iterator position based on a
  80  * timestamp.
  81  */
  82 struct bt_iter_pos *bt_iter_create_time_pos(struct bt_iter *iter,
  83                 uint64_t timestamp);
  84
  85 #endif /* _BABELTRACE_ITERATOR_H */