Version 1.0.0-rc6
[babeltrace.git] / lib / registry.c
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1/*
2 * BabelTrace
3 *
4 * Format Registry
5 *
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6 * Copyright 2010-2011 EfficiOS Inc. and Linux Foundation
7 *
8 * Author: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
fc93b2bd 9 *
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10 * Permission is hereby granted, free of charge, to any person obtaining a copy
11 * of this software and associated documentation files (the "Software"), to deal
12 * in the Software without restriction, including without limitation the rights
13 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
14 * copies of the Software, and to permit persons to whom the Software is
15 * furnished to do so, subject to the following conditions:
fc93b2bd 16 *
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17 * The above copyright notice and this permission notice shall be included in
18 * all copies or substantial portions of the Software.
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19 */
20
4c8bfb7e 21#include <babeltrace/format.h>
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22#include <glib.h>
23#include <errno.h>
7fb21036 24#include <stdio.h>
3122e6f0 25#include <assert.h>
fc93b2bd 26
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27struct walk_data {
28 FILE *fp;
29 int iter;
30};
31
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32/*
33 * Format registry hash table contains the registered formats. Format
34 * registration is typically performed by a format plugin.
fc93b2bd 35 */
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36static GHashTable *format_registry;
37static int format_refcount;
38static int init_done;
39
40static __attribute__((constructor)) void format_init(void);
41
42static
43void format_refcount_inc(void)
44{
45 format_refcount++;
46}
47
48static
49void format_cleanup(void)
50{
51 if (format_registry)
52 g_hash_table_destroy(format_registry);
53}
54
55static
56void format_refcount_dec(void)
57{
58 if (!--format_refcount)
59 format_cleanup();
60}
fc93b2bd 61
34861b9d 62struct format *bt_lookup_format(bt_intern_str name)
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63{
64 if (!init_done)
65 return NULL;
7f89ddce 66
fc93b2bd 67 return g_hash_table_lookup(format_registry,
34861b9d 68 (gconstpointer) (unsigned long) name);
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69}
70
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71static void show_format(gpointer key, gpointer value, gpointer user_data)
72{
d2b8ea6b 73 struct walk_data *data = user_data;
7fb21036 74
d2b8ea6b 75 fprintf(data->fp, "%s%s", data->iter ? ", " : "",
7fb21036 76 g_quark_to_string((GQuark) (unsigned long) key));
d2b8ea6b 77 data->iter++;
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78}
79
80void bt_fprintf_format_list(FILE *fp)
81{
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82 struct walk_data data;
83
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84 assert(fp);
85
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86 data.fp = fp;
87 data.iter = 0;
88
89 fprintf(fp, "Formats available: ");
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90 if (!init_done)
91 return;
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92 g_hash_table_foreach(format_registry, show_format, &data);
93 if (data.iter == 0)
94 fprintf(fp, "<none>");
95 fprintf(fp, ".\n");
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96}
97
4c8bfb7e 98int bt_register_format(struct format *format)
fc93b2bd 99{
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100 if (!format)
101 return -EINVAL;
102
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103 if (!init_done)
104 format_init();
105
4c8bfb7e 106 if (bt_lookup_format(format->name))
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107 return -EEXIST;
108
95febab3 109 format_refcount_inc();
fc93b2bd 110 g_hash_table_insert(format_registry,
4c8bfb7e 111 (gpointer) (unsigned long) format->name,
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112 format);
113 return 0;
114}
115
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116void bt_unregister_format(struct format *format)
117{
118 assert(bt_lookup_format(format->name));
119 g_hash_table_remove(format_registry,
120 (gpointer) (unsigned long) format->name);
121 format_refcount_dec();
122}
123
124/*
125 * We cannot assume that the constructor and destructor order will be
126 * right: another library might be loaded before us, and initialize us
127 * from bt_register_format(). This is why we use a reference count to
128 * handle cleanup of this module. The format_finalize destructor
129 * refcount decrement matches format_init refcount increment.
130 */
131static __attribute__((constructor))
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132void format_init(void)
133{
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134 if (init_done)
135 return;
95febab3 136 format_refcount_inc();
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137 format_registry = g_hash_table_new(g_direct_hash, g_direct_equal);
138 assert(format_registry);
139 init_done = 1;
140}
141
95febab3 142static __attribute__((destructor))
4c8bfb7e 143void format_finalize(void)
fc93b2bd 144{
95febab3 145 format_refcount_dec();
fc93b2bd 146}
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