[babeltrace.git] / lib / registry.c

/*
 * BabelTrace
 *
 * Format Registry
 *
 * Copyright 2010-2011 EfficiOS Inc. and Linux Foundation
 *
 * Author: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <babeltrace/format.h>
#include <glib.h>
#include <errno.h>
#include <stdio.h>
#include <assert.h>

struct walk_data {
	FILE *fp;
	int iter;
};

/*
 * Format registry hash table contains the registered formats. Format
 * registration is typically performed by a format plugin.
 */
static GHashTable *format_registry;
static int format_refcount;
static int init_done;

static __attribute__((constructor)) void format_init(void);

static
void format_refcount_inc(void)
{
	format_refcount++;
}

static
void format_cleanup(void)
{
	if (format_registry)
		g_hash_table_destroy(format_registry);
}

static
void format_refcount_dec(void)
{
	if (!--format_refcount)
		format_cleanup();
}

struct format *bt_lookup_format(bt_intern_str name)
{
	if (!init_done)
		return NULL;

	return g_hash_table_lookup(format_registry,
				   (gconstpointer) (unsigned long) name);
}

static void show_format(gpointer key, gpointer value, gpointer user_data)
{
	struct walk_data *data = user_data;

	fprintf(data->fp, "%s%s", data->iter ? ", " : "",
		g_quark_to_string((GQuark) (unsigned long) key));
	data->iter++;
}

void bt_fprintf_format_list(FILE *fp)
{
	struct walk_data data;

	assert(fp);

	data.fp = fp;
	data.iter = 0;

	fprintf(fp, "Formats available: ");
	if (!init_done)
		return;
	g_hash_table_foreach(format_registry, show_format, &data);
	if (data.iter == 0)
		fprintf(fp, "<none>");
	fprintf(fp, ".\n");
}

int bt_register_format(struct format *format)
{
	if (!format)
		return -EINVAL;

	if (!init_done)
		format_init();

	if (bt_lookup_format(format->name))
		return -EEXIST;

	format_refcount_inc();
	g_hash_table_insert(format_registry,
			    (gpointer) (unsigned long) format->name,
			    format);
	return 0;
}

void bt_unregister_format(struct format *format)
{
	assert(bt_lookup_format(format->name));
	g_hash_table_remove(format_registry,
			    (gpointer) (unsigned long) format->name);
	format_refcount_dec();
}

/*
 * We cannot assume that the constructor and destructor order will be
 * right: another library might be loaded before us, and initialize us
 * from bt_register_format(). This is why we use a reference count to
 * handle cleanup of this module. The format_finalize destructor
 * refcount decrement matches format_init refcount increment.
 */
static __attribute__((constructor))
void format_init(void)
{
	if (init_done)
		return;
	format_refcount_inc();
	format_registry = g_hash_table_new(g_direct_hash, g_direct_equal);
	assert(format_registry);
	init_done = 1;
}

static __attribute__((destructor))
void format_finalize(void)
{
	format_refcount_dec();
}
Commit	Line	Data
	1	/*
	2	* BabelTrace
	3	*
	4	* Format Registry
	5	*
	6	* Copyright 2010-2011 EfficiOS Inc. and Linux Foundation
	7	*
	8	* Author: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	9	*
	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:
	16	*
	17	* The above copyright notice and this permission notice shall be included in
	18	* all copies or substantial portions of the Software.
	19	*
	20	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	21	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	22	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	23	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	24	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	25	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
	26	* SOFTWARE.
	27	*/
	28
	29	#include <babeltrace/format.h>
	30	#include <glib.h>
	31	#include <errno.h>
	32	#include <stdio.h>
	33	#include <assert.h>
	34
	35	struct walk_data {
	36	FILE *fp;
	37	int iter;
	38	};
	39
	40	/*
	41	* Format registry hash table contains the registered formats. Format
	42	* registration is typically performed by a format plugin.
	43	*/
	44	static GHashTable *format_registry;
	45	static int format_refcount;
	46	static int init_done;
	47
	48	static __attribute__((constructor)) void format_init(void);
	49
	50	static
	51	void format_refcount_inc(void)
	52	{
	53	format_refcount++;
	54	}
	55
	56	static
	57	void format_cleanup(void)
	58	{
	59	if (format_registry)
	60	g_hash_table_destroy(format_registry);
	61	}
	62
	63	static
	64	void format_refcount_dec(void)
	65	{
	66	if (!--format_refcount)
	67	format_cleanup();
	68	}
	69
	70	struct format *bt_lookup_format(bt_intern_str name)
	71	{
	72	if (!init_done)
	73	return NULL;
	74
	75	return g_hash_table_lookup(format_registry,
	76	(gconstpointer) (unsigned long) name);
	77	}
	78
	79	static void show_format(gpointer key, gpointer value, gpointer user_data)
	80	{
	81	struct walk_data *data = user_data;
	82
	83	fprintf(data->fp, "%s%s", data->iter ? ", " : "",
	84	g_quark_to_string((GQuark) (unsigned long) key));
	85	data->iter++;
	86	}
	87
	88	void bt_fprintf_format_list(FILE *fp)
	89	{
	90	struct walk_data data;
	91
	92	assert(fp);
	93
	94	data.fp = fp;
	95	data.iter = 0;
	96
	97	fprintf(fp, "Formats available: ");
	98	if (!init_done)
	99	return;
	100	g_hash_table_foreach(format_registry, show_format, &data);
	101	if (data.iter == 0)
	102	fprintf(fp, "<none>");
	103	fprintf(fp, ".\n");
	104	}
	105
	106	int bt_register_format(struct format *format)
	107	{
	108	if (!format)
	109	return -EINVAL;
	110
	111	if (!init_done)
	112	format_init();
	113
	114	if (bt_lookup_format(format->name))
	115	return -EEXIST;
	116
	117	format_refcount_inc();
	118	g_hash_table_insert(format_registry,
	119	(gpointer) (unsigned long) format->name,
	120	format);
	121	return 0;
	122	}
	123
	124	void bt_unregister_format(struct format *format)
	125	{
	126	assert(bt_lookup_format(format->name));
	127	g_hash_table_remove(format_registry,
	128	(gpointer) (unsigned long) format->name);
	129	format_refcount_dec();
	130	}
	131
	132	/*
	133	* We cannot assume that the constructor and destructor order will be
	134	* right: another library might be loaded before us, and initialize us
	135	* from bt_register_format(). This is why we use a reference count to
	136	* handle cleanup of this module. The format_finalize destructor
	137	* refcount decrement matches format_init refcount increment.
	138	*/
	139	static __attribute__((constructor))
	140	void format_init(void)
	141	{
	142	if (init_done)
	143	return;
	144	format_refcount_inc();
	145	format_registry = g_hash_table_new(g_direct_hash, g_direct_equal);
	146	assert(format_registry);
	147	init_done = 1;
	148	}
	149
	150	static __attribute__((destructor))
	151	void format_finalize(void)
	152	{
	153	format_refcount_dec();
	154	}