include/babeltrace/ctf/callbacks.h

   1 #ifndef _BABELTRACE_CTF_CALLBACKS_H
   2 #define _BABELTRACE_CTF_CALLBACKS_H
   3
   4 /*
   5  * BabelTrace
   6  *
   7  * CTF events API
   8  *
   9  * Copyright 2011-2012 EfficiOS Inc. and Linux Foundation
  10  *
  11  * Author: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  12  *         Julien Desfossez <julien.desfossez@efficios.com>
  13  *
  14  * Permission is hereby granted, free of charge, to any person obtaining
  15  * a copy of this software and associated documentation files (the
  16  * "Software"), to deal in the Software without restriction, including
  17  * without limitation the rights to use, copy, modify, merge, publish,
  18  * distribute, sublicense, and/or sell copies of the Software, and to
  19  * permit persons to whom the Software is furnished to do so, subject to
  20  * the following conditions:
  21  *
  22  * The above copyright notice and this permission notice shall be
  23  * included in all copies or substantial portions of the Software.
  24  */
  25
  26 #include <babeltrace/format.h>
  27
  28 /* Forward declarations */
  29 struct bt_ctf_iter;
  30 struct bt_dependencies;
  31
  32 enum bt_cb_ret {
  33         BT_CB_OK                = 0,
  34         BT_CB_OK_STOP           = 1,
  35         BT_CB_ERROR_STOP        = 2,
  36         BT_CB_ERROR_CONTINUE    = 3,
  37 };
  38
  39 /*
  40  * Receives a variable number of strings as parameter, ended with NULL.
  41  */
  42 struct bt_dependencies *babeltrace_dependencies_create(const char *first, ...);
  43
  44 /*
  45  * struct bt_dependencies must be destroyed explicitly if not passed as
  46  * parameter to a bt_ctf_iter_add_callback().
  47  */
  48 void babeltrace_dependencies_destroy(struct bt_dependencies *dep);
  49
  50 /*
  51  * bt_ctf_iter_add_callback: Add a callback to iterator.
  52  *
  53  * @iter: trace collection iterator (input)
  54  * @event: event to target. 0 for all events.
  55  * @private_data: private data pointer to pass to the callback
  56  * @flags: specific flags controlling the behavior of this callback
  57  *         (or'd).
  58  *
  59  * @callback: function pointer to call
  60  * @depends: struct bt_dependency detailing the required computation results.
  61  *           Ends with 0. NULL is accepted as empty dependency.
  62  * @weak_depends: struct bt_dependency detailing the optional computation
  63  *                results that can be optionally consumed by this
  64  *                callback. NULL is accepted as empty dependency.
  65  * @provides: struct bt_dependency detailing the computation results
  66  *            provided by this callback.
  67  *            Ends with 0. NULL is accepted as empty dependency.
  68  *
  69  * "depends", "weak_depends" and "provides" memory is handled by the
  70  * babeltrace library after this call succeeds or fails. These objects
  71  * can still be used by the caller until the babeltrace iterator is
  72  * destroyed, but they belong to the babeltrace library.
  73  *
  74  * (note to implementor: we need to keep a gptrarray of struct
  75  * bt_dependencies to "garbage collect" in struct bt_ctf_iter, and
  76  * dependencies need to have a refcount to handle the case where they
  77  * would be passed to more than one iterator. Upon iterator detroy, we
  78  * iterate on all the gc ptrarray and decrement the refcounts, freeing
  79  * if we reach 0.)
  80  * (note to implementor: we calculate the dependency graph when
  81  * bt_ctf_iter_read_event() is executed after a
  82  * bt_ctf_iter_add_callback(). Beware that it is valid to create/add
  83  * callbacks/read/add more callbacks/read some more.)
  84  */
  85 int bt_ctf_iter_add_callback(struct bt_ctf_iter *iter,
  86                 bt_intern_str event, void *private_data, int flags,
  87                 enum bt_cb_ret (*callback)(struct bt_ctf_event *ctf_data,
  88                                            void *caller_data),
  89                 struct bt_dependencies *depends,
  90                 struct bt_dependencies *weak_depends,
  91                 struct bt_dependencies *provides);
  92
  93 /*
  94  * For flags parameter above.
  95  */
  96 enum {
  97         BT_FLAGS_FREE_PRIVATE_DATA      = (1 << 0),
  98 };
  99
 100 #endif /*_BABELTRACE_CTF_CALLBACKS_H */