lib/registry.c

   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
  21 #include <babeltrace/format.h>
  22 #include <glib.h>
  23 #include <errno.h>
  24 #include <stdio.h>
  25 #include <assert.h>
  26
  27 struct walk_data {
  28         FILE *fp;
  29         int iter;
  30 };
  31
  32 static int init_done;
  33 void __attribute__((constructor)) format_init(void);
  34 void __attribute__((destructor)) format_finalize(void);
  35
  36 /*
  37  * Format registry hash table contains the registered formats. Format
  38  * registration is typically performed by a format plugin.
  39  * TODO: support plugin unload (unregistration of formats).
  40  */
  41 GHashTable *format_registry;
  42
  43 struct format *bt_lookup_format(bt_intern_str name)
  44 {
  45         if (!init_done)
  46                 return NULL;
  47         return g_hash_table_lookup(format_registry,
  48                                    (gconstpointer) (unsigned long) name);
  49 }
  50
  51 static void show_format(gpointer key, gpointer value, gpointer user_data)
  52 {
  53         struct walk_data *data = user_data;
  54
  55         fprintf(data->fp, "%s%s", data->iter ? ", " : "",
  56                 g_quark_to_string((GQuark) (unsigned long) key));
  57         data->iter++;
  58 }
  59
  60 void bt_fprintf_format_list(FILE *fp)
  61 {
  62         struct walk_data data;
  63
  64         data.fp = fp;
  65         data.iter = 0;
  66
  67         fprintf(fp, "Formats available: ");
  68         if (!init_done)
  69                 return;
  70         g_hash_table_foreach(format_registry, show_format, &data);
  71         if (data.iter == 0)
  72                 fprintf(fp, "<none>");
  73         fprintf(fp, ".\n");
  74 }
  75
  76 int bt_register_format(struct format *format)
  77 {
  78         if (!init_done)
  79                 format_init();
  80
  81         if (bt_lookup_format(format->name))
  82                 return -EEXIST;
  83
  84         g_hash_table_insert(format_registry,
  85                             (gpointer) (unsigned long) format->name,
  86                             format);
  87         return 0;
  88 }
  89
  90 void format_init(void)
  91 {
  92         if (init_done)
  93                 return;
  94         format_registry = g_hash_table_new(g_direct_hash, g_direct_equal);
  95         assert(format_registry);
  96         init_done = 1;
  97 }
  98
  99 void format_finalize(void)
 100 {
 101         g_hash_table_destroy(format_registry);
 102 }