include/babeltrace/babeltrace.h

   1 #ifndef _BABELTRACE_H
   2 #define _BABELTRACE_H
   3
   4 /*
   5  * BabelTrace API
   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 /* Forward declarations */
  21 struct babeltrace_iter;
  22 struct trace_collection;
  23 struct ctf_stream_event;
  24 struct ctf_stream;
  25 struct babeltrace_saved_pos;
  26
  27 struct trace_collection_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 babeltrace_saved_pos *restore;
  38         } u;
  39 };
  40
  41 /*
  42  * babeltrace_iter_create - Allocate a trace collection iterator.
  43  *
  44  * begin_pos and end_pos are optional parameters to specify the position
  45  * at which the trace collection should be seeked upon iterator
  46  * creation, and the position at which iteration will start returning
  47  * "EOF".
  48  *
  49  * By default, if begin_pos is NULL, a BT_SEEK_CUR is performed at
  50  * creation. By default, if end_pos is NULL, a BT_SEEK_END (end of
  51  * trace) is the EOF criterion.
  52  */
  53 struct babeltrace_iter *babeltrace_iter_create(struct trace_collection *tc,
  54                 struct trace_collection_pos *begin_pos,
  55                 struct trace_collection_pos *end_pos);
  56
  57 /*
  58  * babeltrace_iter_destroy - Free a trace collection iterator.
  59  */
  60 void babeltrace_iter_destroy(struct babeltrace_iter *iter);
  61
  62 /*
  63  * babeltrace_iter_next: Move trace collection position to the next event.
  64  *
  65  * Returns 0 on success, a negative value on error
  66  */
  67 int babeltrace_iter_next(struct babeltrace_iter *iter);
  68
  69 /*
  70  * babeltrace_iter_save_pos - Save the current trace collection position.
  71  *
  72  * The position returned by this function needs to be freed by
  73  * babeltrace_iter_free_pos after use.
  74  */
  75 struct trace_collection_pos *
  76         babeltrace_iter_save_pos(struct babeltrace_iter *iter);
  77
  78 /*
  79  * babeltrace_iter_free_pos - Free the position.
  80  */
  81 void babeltrace_iter_free_pos(struct trace_collection_pos *pos);
  82
  83 /*
  84  * babeltrace_iter_seek: seek iterator to given position.
  85  *
  86  * Return EOF if position is after the last event of the trace collection.
  87  * Return other negative value for other errors.
  88  * Return 0 for success.
  89  */
  90 int babeltrace_iter_seek(struct babeltrace_iter *iter,
  91                 const struct trace_collection_pos *pos);
  92
  93 /*
  94  * babeltrace_iter_read_event: Read the iterator's current event data.
  95  *
  96  * @iter: trace collection iterator (input)
  97  * @stream: stream containing event at current position (output)
  98  * @event: current event (output)
  99  * Return 0 on success, negative error value on error.
 100  */
 101 int babeltrace_iter_read_event(struct babeltrace_iter *iter,
 102                 struct ctf_stream **stream,
 103                 struct ctf_stream_event **event);
 104
 105 #endif /* _BABELTRACE_H */