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 #include <babeltrace/ctf/events.h>
  23
  24 /* Forward declarations */
  25 struct bt_iter;
  26 struct ctf_stream_event;
  27 struct ctf_stream;
  28 struct bt_saved_pos;
  29
  30 struct bt_iter_pos {
  31         enum {
  32                 BT_SEEK_TIME,           /* uses u.seek_time */
  33                 BT_SEEK_RESTORE,        /* uses u.restore */
  34                 BT_SEEK_CUR,
  35                 BT_SEEK_BEGIN,
  36                 BT_SEEK_END,
  37         } type;
  38         union {
  39                 uint64_t seek_time;
  40                 struct bt_saved_pos *restore;
  41         } u;
  42 };
  43
  44 /*
  45  * bt_iter_create - Allocate a trace collection iterator.
  46  *
  47  * begin_pos and end_pos are optional parameters to specify the position
  48  * at which the trace collection should be seeked upon iterator
  49  * creation, and the position at which iteration will start returning
  50  * "EOF".
  51  *
  52  * By default, if begin_pos is NULL, a BT_SEEK_CUR is performed at
  53  * creation. By default, if end_pos is NULL, a BT_SEEK_END (end of
  54  * trace) is the EOF criterion.
  55  */
  56 struct bt_iter *bt_iter_create(struct bt_context *ctx,
  57                 struct bt_iter_pos *begin_pos,
  58                 struct bt_iter_pos *end_pos);
  59
  60 /*
  61  * bt_iter_destroy - Free a trace collection iterator.
  62  */
  63 void bt_iter_destroy(struct bt_iter *iter);
  64
  65 /*
  66  * bt_iter_next: Move trace collection position to the next event.
  67  *
  68  * Returns 0 on success, a negative value on error
  69  */
  70 int bt_iter_next(struct bt_iter *iter);
  71
  72 /*
  73  * bt_iter_get_pos - Get the current iterator position.
  74  *
  75  * The position returned by this function needs to be freed by
  76  * bt_iter_free_pos after use.
  77  */
  78 struct bt_iter_pos *
  79         bt_iter_get_pos(struct bt_iter *iter);
  80
  81 /*
  82  * bt_iter_free_pos - Free the position.
  83  */
  84 void bt_iter_free_pos(struct bt_iter_pos *pos);
  85
  86 /*
  87  * bt_iter_set_pos: move the iterator to a given position.
  88  *
  89  * On error, the stream_heap is reinitialized and returned empty.
  90  *
  91  * Return 0 for success.
  92  *
  93  * Return EOF if the position requested is after the last event of the
  94  * trace collection.
  95  * Return -EINVAL when called with invalid parameter.
  96  * Return -ENOMEM if the stream_heap could not be properly initialized.
  97  */
  98 int bt_iter_set_pos(struct bt_iter *iter, const struct bt_iter_pos *pos);
  99
 100 /*
 101  * bt_iter_create_time_pos: create a position based on time
 102  *
 103  * This function allocates and returns a new bt_iter_pos (which must be freed
 104  * with bt_iter_free_pos) to be able to restore an iterator position based on a
 105  * timestamp.
 106  */
 107 struct bt_iter_pos *bt_iter_create_time_pos(struct bt_iter *iter,
 108                 uint64_t timestamp);
 109
 110 /*
 111  * bt_iter_read_ctf_event: Read the iterator's current event data.
 112  *
 113  * @iter: trace collection iterator (input)
 114  * @stream: stream containing event at current position (output)
 115  * @event: current event (output)
 116  * Return 0 on success, negative error value on error.
 117  */
 118 struct bt_ctf_event *bt_iter_read_ctf_event(struct bt_iter *iter);
 119
 120 #endif /* _BABELTRACE_ITERATOR_H */