formats/registry.c

   1 /*
   2  * BabelTrace
   3  *
   4  * Format Registry
   5  *
   6  * Copyright 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a copy
   9  * of this software and associated documentation files (the "Software"), to deal
  10  * in the Software without restriction, including without limitation the rights
  11  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  12  * copies of the Software, and to permit persons to whom the Software is
  13  * furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included in
  16  * all copies or substantial portions of the Software.
  17  */
  18
  19 #include <babeltrace/format.h>
  20 #include <glib.h>
  21 #include <errno.h>
  22 #include <stdio.h>
  23
  24 struct walk_data {
  25         FILE *fp;
  26         int iter;
  27 };
  28
  29 static int init_done;
  30 void __attribute__((constructor)) format_init(void);
  31 void __attribute__((destructor)) format_finalize(void);
  32
  33 /*
  34  * Format registry hash table contains the registered formats. Format
  35  * registration is typically performed by a format plugin.
  36  * TODO: support plugin unload (unregistration of formats).
  37  */
  38 GHashTable *format_registry;
  39
  40 struct format *bt_lookup_format(GQuark qname)
  41 {
  42         if (!init_done)
  43                 return NULL;
  44         return g_hash_table_lookup(format_registry,
  45                                    (gconstpointer) (unsigned long) qname);
  46 }
  47
  48 static void show_format(gpointer key, gpointer value, gpointer user_data)
  49 {
  50         struct walk_data *data = user_data;
  51
  52         fprintf(data->fp, "%s%s", data->iter ? ", " : "",
  53                 g_quark_to_string((GQuark) (unsigned long) key));
  54         data->iter++;
  55 }
  56
  57 void bt_fprintf_format_list(FILE *fp)
  58 {
  59         struct walk_data data;
  60
  61         data.fp = fp;
  62         data.iter = 0;
  63
  64         fprintf(fp, "Formats available: ");
  65         if (!init_done)
  66                 return;
  67         g_hash_table_foreach(format_registry, show_format, &data);
  68         if (data.iter == 0)
  69                 fprintf(fp, "<none>");
  70         fprintf(fp, ".\n");
  71 }
  72
  73 int bt_register_format(struct format *format)
  74 {
  75         if (!init_done)
  76                 format_init();
  77
  78         if (bt_lookup_format(format->name))
  79                 return -EEXIST;
  80
  81         g_hash_table_insert(format_registry,
  82                             (gpointer) (unsigned long) format->name,
  83                             format);
  84         return 0;
  85 }
  86
  87 void format_init(void)
  88 {
  89         if (init_done)
  90                 return;
  91         format_registry = g_hash_table_new(g_direct_hash, g_direct_equal);
  92         assert(format_registry);
  93         init_done = 1;
  94 }
  95
  96 void format_finalize(void)
  97 {
  98         g_hash_table_destroy(format_registry);
  99 }