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1 | #ifndef _BABELTRACE_CONTEXT_H |
2 | #define _BABELTRACE_CONTEXT_H | |
3 | ||
4 | /* | |
5 | * BabelTrace | |
6 | * | |
7 | * context header | |
8 | * | |
9 | * Copyright 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 a copy | |
15 | * of this software and associated documentation files (the "Software"), to deal | |
16 | * in the Software without restriction, including without limitation the rights | |
17 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
18 | * copies of the Software, and to permit persons to whom the Software is | |
19 | * furnished to do so, subject to the following conditions: | |
20 | * | |
21 | * The above copyright notice and this permission notice shall be included in | |
22 | * all copies or substantial portions of the Software. | |
23 | */ | |
24 | ||
25 | struct trace_collection; | |
26 | ||
27 | /* | |
28 | * The context represents the object in which a trace_collection is open. As | |
29 | * long as this structure is allocated, the trace_collection is open and the | |
30 | * traces it contains can be read and seeked by the iterators and callbacks. | |
31 | * | |
32 | * It has to be created with the bt_context_create() function and destroyed by | |
33 | * bt_context_destroy() | |
34 | */ | |
35 | struct bt_context { | |
36 | struct trace_collection *tc; | |
37 | int refcount; | |
842c2b97 | 38 | int last_trace_handle_id; |
b469d2dd JD |
39 | }; |
40 | ||
41 | /* | |
42 | * bt_context_create : create a Babeltrace context | |
43 | * | |
44 | * Allocate a new context and assign the trace_collection passed in | |
45 | * parameter as the context trace_collection. The trace_collection | |
46 | * must contain an array of valid trace_descriptors. The creation of | |
47 | * the context sets the refcount to 1. | |
48 | * | |
49 | * Returns an allocated context on success and NULL on error | |
50 | */ | |
51 | struct bt_context *bt_context_create(struct trace_collection *tc); | |
52 | ||
53 | /* | |
54 | * bt_context_destroy : destroy a context | |
55 | * | |
56 | * If the context is still in use (by an iterator or a callback), the | |
57 | * destroy fails and returns -1, on success : return 0. | |
58 | */ | |
59 | int bt_context_destroy(struct bt_context *ctx); | |
60 | ||
61 | /* | |
62 | * bt_context_get and bt_context_put : increments and decrement the refcount of | |
63 | * the context | |
64 | * | |
65 | * These functions ensures that the context won't be destroyed when it is in | |
66 | * use. The same number of get and put has to be done to be able to destroy a | |
67 | * context. | |
68 | * | |
69 | * Return 0 on success, -1 if the context pointer is invalid. When the context | |
70 | * refcount is decremented to 0 by a bt_context_put, it calls | |
71 | * bt_context_destroy to free the context. In this case the return code of | |
72 | * bt_context_destroy is returned. | |
73 | */ | |
74 | int bt_context_get(struct bt_context *ctx); | |
75 | int bt_context_put(struct bt_context *ctx); | |
76 | ||
77 | #endif /* _BABELTRACE_CONTEXT_H */ |