API : Access CTF events fields
[babeltrace.git] / include / babeltrace / ctf / events.h
1 #ifndef _BABELTRACE_CTF_EVENTS_H
2 #define _BABELTRACE_CTF_EVENTS_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 <stdint.h>
27
28 struct ctf_stream;
29 struct ctf_stream_event;
30 struct definition;
31
32 /*
33 * the top-level scopes in CTF
34 */
35 enum bt_ctf_scope {
36 BT_TRACE_PACKET_HEADER = 0,
37 BT_STREAM_PACKET_CONTEXT = 1,
38 BT_STREAM_EVENT_HEADER = 2,
39 BT_STREAM_EVENT_CONTEXT = 3,
40 BT_EVENT_CONTEXT = 4,
41 BT_EVENT_FIELDS = 5,
42 };
43
44 /*
45 * the supported CTF types
46 */
47 enum ctf_type_id {
48 CTF_TYPE_UNKNOWN = 0,
49 CTF_TYPE_INTEGER,
50 CTF_TYPE_FLOAT,
51 CTF_TYPE_ENUM,
52 CTF_TYPE_STRING,
53 CTF_TYPE_STRUCT,
54 CTF_TYPE_UNTAGGED_VARIANT,
55 CTF_TYPE_VARIANT,
56 CTF_TYPE_ARRAY,
57 CTF_TYPE_SEQUENCE,
58 NR_CTF_TYPES,
59 };
60
61 /*
62 * the structure to manipulate events
63 */
64 struct bt_ctf_event {
65 struct ctf_stream *stream;
66 struct ctf_stream_event *event;
67 };
68
69 /*
70 * bt_ctf_get_top_level_scope: return a definition of the top-level scope
71 *
72 * Top-level scopes are defined in the bt_ctf_scope enum.
73 * In order to get a field or a field list, the user needs to pass a
74 * scope as argument, this scope can be a top-level scope or a scope
75 * relative to an arbitrary field. This function provides the mapping
76 * between the enum and the actual definition of top-level scopes.
77 * On error return NULL.
78 */
79 struct definition *bt_ctf_get_top_level_scope(struct bt_ctf_event *event,
80 enum bt_ctf_scope scope);
81
82 /*
83 * bt_ctf_event_get_name: returns the name of the event or NULL on error
84 */
85 const char *bt_ctf_event_name(struct bt_ctf_event *event);
86
87 /*
88 * bt_ctf_get_timestamp: returns the timestamp of the event or -1ULL on error
89 */
90 uint64_t bt_ctf_get_timestamp(struct bt_ctf_event *event);
91
92 /*
93 * bt_ctf_get_field_list: returns an array of *def pointing to each field of
94 * the event. The array is NULL terminated.
95 * On error : return NULL.
96 */
97 int bt_ctf_get_field_list(struct bt_ctf_event *event,
98 struct definition *scope,
99 struct definition const * const **list,
100 unsigned int *count);
101
102 /*
103 * bt_ctf_get_field: returns the definition of a specific field
104 */
105 struct definition *bt_ctf_get_field(struct bt_ctf_event *event,
106 struct definition *scope,
107 const char *field);
108
109 /*
110 * bt_ctf_get_index: if the field is an array or a sequence, return the element
111 * at position index, otherwise return NULL;
112 */
113 struct definition *bt_ctf_get_index(struct bt_ctf_event *event,
114 struct definition *field,
115 unsigned int index);
116
117 /*
118 * bt_ctf_field_name: returns the name of a field or NULL on error
119 */
120 const char *bt_ctf_field_name(const struct definition *def);
121
122 /*
123 * bt_ctf_field_type: returns the type of a field or -1 if unknown
124 */
125 enum ctf_type_id bt_ctf_field_type(struct definition *def);
126
127 /*
128 * Field access functions
129 *
130 * These functions return the value associated with the field passed in
131 * parameter.
132 *
133 * If the field does not exist or is not of the type requested, the value
134 * returned is undefined. To check if an error occured, use the
135 * bt_ctf_field_error() function after accessing a field.
136 */
137 uint64_t bt_ctf_get_uint64(struct definition *field);
138 int64_t bt_ctf_get_int64(struct definition *field);
139 char *bt_ctf_get_char_array(struct definition *field);
140 char *bt_ctf_get_string(struct definition *field);
141
142 /*
143 * bt_ctf_field_error: returns the last error code encountered while
144 * accessing a field and reset the error flag.
145 * Return 0 if no error, a negative value otherwise.
146 */
147 int bt_ctf_field_get_error(void);
148
149 #endif /* _BABELTRACE_CTF_EVENTS_H */
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