glib/glib-init.c

   1 /*
   2  * Copyright © 2011 Canonical Limited
   3  *
   4  * This library is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU Lesser General Public License as
   6  * published by the Free Software Foundation; either version 2 of the
   7  * licence, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  16  *
  17  * Author: Ryan Lortie <desrt@desrt.ca>
  18  */
  19
  20 #include "config.h"
  21
  22 #include "glib-init.h"
  23
  24 #include "glib-private.h"
  25 #include "gtypes.h"
  26 #include "gutils.h"     /* for GDebugKey */
  27 #include "gconstructor.h"
  28 #include "gmem.h"       /* for g_mem_gc_friendly */
  29
  30 #include <string.h>
  31 #include <stdlib.h>
  32 #include <stdio.h>
  33 #include <ctype.h>
  34
  35 /* This seems as good a place as any to make static assertions about platform
  36  * assumptions we make throughout GLib. */
  37
  38 /* We assume that data pointers are the same size as function pointers... */
  39 G_STATIC_ASSERT (sizeof (gpointer) == sizeof (GFunc));
  40 G_STATIC_ASSERT (_g_alignof (gpointer) == _g_alignof (GFunc));
  41 /* ... and that all function pointers are the same size. */
  42 G_STATIC_ASSERT (sizeof (GFunc) == sizeof (GCompareDataFunc));
  43 G_STATIC_ASSERT (_g_alignof (GFunc) == _g_alignof (GCompareDataFunc));
  44
  45 /**
  46  * g_mem_gc_friendly:
  47  *
  48  * This variable is %TRUE if the <envar>G_DEBUG</envar> environment variable
  49  * includes the key <literal>gc-friendly</literal>.
  50  */
  51 #ifdef ENABLE_GC_FRIENDLY_DEFAULT
  52 gboolean g_mem_gc_friendly = TRUE;
  53 #else
  54 gboolean g_mem_gc_friendly = FALSE;
  55 #endif
  56 GLogLevelFlags g_log_msg_prefix = G_LOG_LEVEL_ERROR | G_LOG_LEVEL_WARNING |
  57                                   G_LOG_LEVEL_CRITICAL | G_LOG_LEVEL_DEBUG;
  58 GLogLevelFlags g_log_always_fatal = G_LOG_FATAL_MASK;
  59
  60 static gboolean
  61 debug_key_matches (const gchar *key,
  62                    const gchar *token,
  63                    guint        length)
  64 {
  65   /* may not call GLib functions: see note in g_parse_debug_string() */
  66   for (; length; length--, key++, token++)
  67     {
  68       char k = (*key   == '_') ? '-' : tolower (*key  );
  69       char t = (*token == '_') ? '-' : tolower (*token);
  70
  71       if (k != t)
  72         return FALSE;
  73     }
  74
  75   return *key == '\0';
  76 }
  77
  78 /**
  79  * g_parse_debug_string:
  80  * @string: (allow-none): a list of debug options separated by colons, spaces, or
  81  * commas, or %NULL.
  82  * @keys: (array length=nkeys): pointer to an array of #GDebugKey which associate
  83  *     strings with bit flags.
  84  * @nkeys: the number of #GDebugKeys in the array.
  85  *
  86  * Parses a string containing debugging options
  87  * into a %guint containing bit flags. This is used
  88  * within GDK and GTK+ to parse the debug options passed on the
  89  * command line or through environment variables.
  90  *
  91  * If @string is equal to "all", all flags are set. Any flags
  92  * specified along with "all" in @string are inverted; thus,
  93  * "all,foo,bar" or "foo,bar,all" sets all flags except those
  94  * corresponding to "foo" and "bar".
  95  *
  96  * If @string is equal to "help", all the available keys in @keys
  97  * are printed out to standard error.
  98  *
  99  * Returns: the combined set of bit flags.
 100  */
 101 guint
 102 g_parse_debug_string  (const gchar     *string,
 103                        const GDebugKey *keys,
 104                        guint            nkeys)
 105 {
 106   guint i;
 107   guint result = 0;
 108
 109   if (string == NULL)
 110     return 0;
 111
 112   /* this function is used during the initialisation of gmessages, gmem
 113    * and gslice, so it may not do anything that causes memory to be
 114    * allocated or risks messages being emitted.
 115    *
 116    * this means, more or less, that this code may not call anything
 117    * inside GLib.
 118    */
 119
 120   if (!strcasecmp (string, "help"))
 121     {
 122       /* using stdio directly for the reason stated above */
 123       fprintf (stderr, "Supported debug values:");
 124       for (i = 0; i < nkeys; i++)
 125        fprintf (stderr, " %s", keys[i].key);
 126       fprintf (stderr, " all help\n");
 127     }
 128   else
 129     {
 130       const gchar *p = string;
 131       const gchar *q;
 132       gboolean invert = FALSE;
 133
 134       while (*p)
 135        {
 136          q = strpbrk (p, ":;, \t");
 137          if (!q)
 138            q = p + strlen (p);
 139
 140          if (debug_key_matches ("all", p, q - p))
 141            {
 142              invert = TRUE;
 143            }
 144          else
 145            {
 146              for (i = 0; i < nkeys; i++)
 147                if (debug_key_matches (keys[i].key, p, q - p))
 148                  result |= keys[i].value;
 149            }
 150
 151          p = q;
 152          if (*p)
 153            p++;
 154        }
 155
 156       if (invert)
 157         {
 158           guint all_flags = 0;
 159
 160           for (i = 0; i < nkeys; i++)
 161             all_flags |= keys[i].value;
 162
 163           result = all_flags & (~result);
 164         }
 165     }
 166
 167   return result;
 168 }
 169
 170 static guint
 171 g_parse_debug_envvar (const gchar     *envvar,
 172                       const GDebugKey *keys,
 173                       gint             n_keys,
 174                       guint            default_value)
 175 {
 176   const gchar *value;
 177
 178 #ifdef OS_WIN32
 179   /* "fatal-warnings,fatal-criticals,all,help" is pretty short */
 180   gchar buffer[100];
 181
 182   if (GetEnvironmentVariable (envvar, buffer, 100) < 100)
 183     value = buffer;
 184   else
 185     return 0;
 186 #else
 187   value = getenv (envvar);
 188 #endif
 189
 190   if (value == NULL)
 191     return default_value;
 192
 193   return g_parse_debug_string (value, keys, n_keys);
 194 }
 195
 196 static void
 197 g_messages_prefixed_init (void)
 198 {
 199   const GDebugKey keys[] = {
 200     { "error", G_LOG_LEVEL_ERROR },
 201     { "critical", G_LOG_LEVEL_CRITICAL },
 202     { "warning", G_LOG_LEVEL_WARNING },
 203     { "message", G_LOG_LEVEL_MESSAGE },
 204     { "info", G_LOG_LEVEL_INFO },
 205     { "debug", G_LOG_LEVEL_DEBUG }
 206   };
 207
 208   g_log_msg_prefix = g_parse_debug_envvar ("G_MESSAGES_PREFIXED", keys, G_N_ELEMENTS (keys), g_log_msg_prefix);
 209 }
 210
 211 static void
 212 g_debug_init (void)
 213 {
 214   const GDebugKey keys[] = {
 215     { "gc-friendly", 1 },
 216     {"fatal-warnings",  G_LOG_LEVEL_WARNING | G_LOG_LEVEL_CRITICAL },
 217     {"fatal-criticals", G_LOG_LEVEL_CRITICAL }
 218   };
 219   GLogLevelFlags flags;
 220
 221   flags = g_parse_debug_envvar ("G_DEBUG", keys, G_N_ELEMENTS (keys), 0);
 222
 223   g_log_always_fatal |= flags & G_LOG_LEVEL_MASK;
 224
 225   g_mem_gc_friendly = flags & 1;
 226 }
 227
 228 static void
 229 glib_init (void)
 230 {
 231   g_messages_prefixed_init ();
 232   g_debug_init ();
 233 }
 234
 235 #if defined (G_OS_WIN32)
 236
 237 BOOL WINAPI DllMain (HINSTANCE hinstDLL,
 238                      DWORD     fdwReason,
 239                      LPVOID    lpvReserved);
 240
 241 HMODULE glib_dll;
 242
 243 BOOL WINAPI
 244 DllMain (HINSTANCE hinstDLL,
 245          DWORD     fdwReason,
 246          LPVOID    lpvReserved)
 247 {
 248   switch (fdwReason)
 249     {
 250     case DLL_PROCESS_ATTACH:
 251       glib_dll = hinstDLL;
 252       g_clock_win32_init ();
 253 #ifdef THREADS_WIN32
 254       g_thread_win32_init ();
 255 #endif
 256       glib_init ();
 257       break;
 258
 259     case DLL_THREAD_DETACH:
 260 #ifdef THREADS_WIN32
 261       g_thread_win32_thread_detach ();
 262 #endif
 263       break;
 264
 265     default:
 266       /* do nothing */
 267       ;
 268     }
 269
 270   return TRUE;
 271 }
 272
 273 #elif defined (G_HAS_CONSTRUCTORS)
 274
 275 #ifdef G_DEFINE_CONSTRUCTOR_NEEDS_PRAGMA
 276 #pragma G_DEFINE_CONSTRUCTOR_PRAGMA_ARGS(glib_init_ctor)
 277 #endif
 278 G_DEFINE_CONSTRUCTOR(glib_init_ctor)
 279
 280 static void
 281 glib_init_ctor (void)
 282 {
 283   glib_init ();
 284 }
 285
 286 #else
 287 # error Your platform/compiler is missing constructor support
 288 #endif