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 typedef GQuark bt_event_name;
  24
  25 /* Forward declarations */
  26 struct babeltrace_iter;
  27 struct ctf_stream_event;
  28 struct ctf_stream;
  29 struct babeltrace_saved_pos;
  30
  31 struct trace_collection_pos {
  32         enum {
  33                 BT_SEEK_TIME,           /* uses u.seek_time */
  34                 BT_SEEK_RESTORE,        /* uses u.restore */
  35                 BT_SEEK_CUR,
  36                 BT_SEEK_BEGIN,
  37                 BT_SEEK_END,
  38         } type;
  39         union {
  40                 uint64_t seek_time;
  41                 struct babeltrace_saved_pos *restore;
  42         } u;
  43 };
  44
  45 /*
  46  * babeltrace_iter_create - Allocate a trace collection iterator.
  47  *
  48  * begin_pos and end_pos are optional parameters to specify the position
  49  * at which the trace collection should be seeked upon iterator
  50  * creation, and the position at which iteration will start returning
  51  * "EOF".
  52  *
  53  * By default, if begin_pos is NULL, a BT_SEEK_CUR is performed at
  54  * creation. By default, if end_pos is NULL, a BT_SEEK_END (end of
  55  * trace) is the EOF criterion.
  56  */
  57 struct babeltrace_iter *babeltrace_iter_create(struct bt_context *ctx,
  58                 struct trace_collection_pos *begin_pos,
  59                 struct trace_collection_pos *end_pos);
  60
  61 /*
  62  * babeltrace_iter_destroy - Free a trace collection iterator.
  63  */
  64 void babeltrace_iter_destroy(struct babeltrace_iter *iter);
  65
  66 /*
  67  * babeltrace_iter_next: Move trace collection position to the next event.
  68  *
  69  * Returns 0 on success, a negative value on error
  70  */
  71 int babeltrace_iter_next(struct babeltrace_iter *iter);
  72
  73 /*
  74  * babeltrace_iter_save_pos - Save the current trace collection position.
  75  *
  76  * The position returned by this function needs to be freed by
  77  * babeltrace_iter_free_pos after use.
  78  */
  79 struct trace_collection_pos *
  80         babeltrace_iter_save_pos(struct babeltrace_iter *iter);
  81
  82 /*
  83  * babeltrace_iter_free_pos - Free the position.
  84  */
  85 void babeltrace_iter_free_pos(struct trace_collection_pos *pos);
  86
  87 /*
  88  * babeltrace_iter_seek: seek iterator to given position.
  89  *
  90  * Return EOF if position is after the last event of the trace collection.
  91  * Return other negative value for other errors.
  92  * Return 0 for success.
  93  */
  94 int babeltrace_iter_seek(struct babeltrace_iter *iter,
  95                 const struct trace_collection_pos *pos);
  96
  97 /*
  98  * babeltrace_iter_read_event: Read the iterator's current event data.
  99  *
 100  * @iter: trace collection iterator (input)
 101  * @stream: stream containing event at current position (output)
 102  * @event: current event (output)
 103  * Return 0 on success, negative error value on error.
 104  */
 105 int babeltrace_iter_read_event(struct babeltrace_iter *iter,
 106                 struct ctf_stream **stream,
 107                 struct ctf_stream_event **event);
 108
 109 #endif /* _BABELTRACE_ITERATOR_H */