gthread.c

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/* GLIB - Library of useful routines for C programming
 * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
 *
 * gmutex.c: MT safety related functions
 * Copyright 1998 Sebastian Wilhelmi; University of Karlsruhe
 *                Owen Taylor
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

/*
 * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
 * file for a list of people on the GLib Team.  See the ChangeLog
 * files for a list of changes.  These files are distributed with
 * GLib at ftp://ftp.gtk.org/pub/gtk/. 
 */

/* 
 * MT safe
 */

#include "glibconfig.h"
#include "glib.h"

#ifdef G_THREAD_USE_PID_SURROGATE
#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <errno.h>
#endif /* G_THREAD_USE_PID_SURROGATE */

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#include <string.h>

#if GLIB_SIZEOF_SYSTEM_THREAD == SIZEOF_VOID_P
# define g_system_thread_equal_simple(thread1, thread2)			\
   ((thread1).dummy_pointer == (thread2).dummy_pointer)
# define g_system_thread_assign(dest, src)				\
   ((dest).dummy_pointer = (src).dummy_pointer)
#else /* GLIB_SIZEOF_SYSTEM_THREAD != SIZEOF_VOID_P */
# define g_system_thread_equal_simple(thread1, thread2)			\
   (memcmp (&(thread1), &(thread2), GLIB_SIZEOF_SYSTEM_THREAD) == 0)
# define g_system_thread_assign(dest, src)				\
   (memcpy (&(dest), &(src), GLIB_SIZEOF_SYSTEM_THREAD))
#endif /* GLIB_SIZEOF_SYSTEM_THREAD == SIZEOF_VOID_P */

#define g_system_thread_equal(thread1, thread2)				\
  (g_thread_functions_for_glib_use.thread_equal ? 			\
   g_thread_functions_for_glib_use.thread_equal (&(thread1), &(thread2)) :\
   g_system_thread_equal_simple((thread1), (thread2)))

GQuark 
g_thread_error_quark (void)
{
  static GQuark quark;
  if (!quark)
    quark = g_quark_from_static_string ("g_thread_error");
  return quark;
}

/* Keep this in sync with GRealThread in gmain.c! */
typedef struct _GRealThread GRealThread;
struct  _GRealThread
{
  GThread thread;
  gpointer private_data;
  gpointer retval;
  GSystemThread system_thread;
#ifdef G_THREAD_USE_PID_SURROGATE
  pid_t pid;
#endif /* G_THREAD_USE_PID_SURROGATE */
};

#ifdef G_THREAD_USE_PID_SURROGATE
static gint priority_map[] = { 15, 0, -15, -20 };
static gboolean prio_warned = FALSE;
# define SET_PRIO(pid, prio) G_STMT_START{				\
  gint error = setpriority (PRIO_PROCESS, (pid), priority_map[prio]);	\
  if (error == -1 && errno == EACCES && !prio_warned)			\
    {									\
      prio_warned = TRUE;						\
      g_warning ("Priorities can only be increased by root.");		\
    }									\
  }G_STMT_END
#endif /* G_THREAD_USE_PID_SURROGATE */

typedef struct _GStaticPrivateNode GStaticPrivateNode;
struct _GStaticPrivateNode
{
  gpointer       data;
  GDestroyNotify destroy;
};

static void g_thread_cleanup (gpointer data);
static void g_thread_fail (void);

/* Global variables */

static GSystemThread zero_thread; /* This is initialized to all zero */
gboolean g_thread_use_default_impl = TRUE;
gboolean g_threads_got_initialized = FALSE;

#if defined(G_PLATFORM_WIN32) && defined(__GNUC__)
__declspec(dllexport)
#endif
GThreadFunctions g_thread_functions_for_glib_use = {
  (GMutex*(*)())g_thread_fail,                 /* mutex_new */
  NULL,                                        /* mutex_lock */
  NULL,                                        /* mutex_trylock */
  NULL,                                        /* mutex_unlock */
  NULL,                                        /* mutex_free */
  (GCond*(*)())g_thread_fail,                  /* cond_new */
  NULL,                                        /* cond_signal */
  NULL,                                        /* cond_broadcast */
  NULL,                                        /* cond_wait */
  NULL,                                        /* cond_timed_wait  */
  NULL,                                        /* cond_free */
  (GPrivate*(*)(GDestroyNotify))g_thread_fail, /* private_new */
  NULL,                                        /* private_get */
  NULL,                                        /* private_set */
  (void(*)(GThreadFunc, gpointer, gulong, 
	   gboolean, gboolean, GThreadPriority, 
	   gpointer, GError**))g_thread_fail,  /* thread_create */
  NULL,                                        /* thread_yield */
  NULL,                                        /* thread_join */
  NULL,                                        /* thread_exit */
  NULL,                                        /* thread_set_priority */
  NULL                                         /* thread_self */
}; 

/* Local data */

static GMutex   *g_mutex_protect_static_mutex_allocation = NULL;
static GPrivate *g_thread_specific_private = NULL;
static GSList   *g_thread_all_threads = NULL;
static GSList   *g_thread_free_indeces = NULL;

G_LOCK_DEFINE_STATIC (g_thread);

/* This must be called only once, before any threads are created.
 * It will only be called from g_thread_init() in -lgthread.
 */
void
g_mutex_init (void)
{
  GRealThread* main_thread;
 
  /* We let the main thread (the one that calls g_thread_init) inherit
   * the data, that it set before calling g_thread_init
   */
  main_thread = (GRealThread*) g_thread_self ();

  g_thread_specific_private = g_private_new (g_thread_cleanup);
  G_THREAD_UF (private_set, (g_thread_specific_private, main_thread));
  G_THREAD_UF (thread_self, (&main_thread->system_thread));

  g_mutex_protect_static_mutex_allocation = g_mutex_new ();
}

void 
g_static_mutex_init (GStaticMutex *mutex)
{
  static GStaticMutex init_mutex = G_STATIC_MUTEX_INIT;

  g_return_if_fail (mutex);

  *mutex = init_mutex;
}

GMutex *
g_static_mutex_get_mutex_impl (GMutex** mutex)
{
  if (!g_thread_supported ())
    return NULL;

  g_assert (g_mutex_protect_static_mutex_allocation);

  g_mutex_lock (g_mutex_protect_static_mutex_allocation);

  if (!(*mutex)) 
    *mutex = g_mutex_new (); 

  g_mutex_unlock (g_mutex_protect_static_mutex_allocation);
  
  return *mutex;
}

void
g_static_mutex_free (GStaticMutex* mutex)
{
  GMutex **runtime_mutex;
  
  g_return_if_fail (mutex);

  /* The runtime_mutex is the first (or only) member of GStaticMutex,
   * see both versions (of glibconfig.h) in configure.in */
  runtime_mutex = ((GMutex**)mutex);
  
  if (*runtime_mutex)
    g_mutex_free (*runtime_mutex);

  *runtime_mutex = NULL;
}

void     
g_static_rec_mutex_init (GStaticRecMutex *mutex)
{
  static GStaticRecMutex init_mutex = G_STATIC_REC_MUTEX_INIT;
  
  g_return_if_fail (mutex);

  *mutex = init_mutex;
}

void
g_static_rec_mutex_lock (GStaticRecMutex* mutex)
{
  GSystemThread self;

  g_return_if_fail (mutex);

  if (!g_thread_supported ())
    return;

  G_THREAD_UF (thread_self, (&self));

  if (g_system_thread_equal (self, mutex->owner))
    {
      mutex->depth++;
      return;
    }
  g_static_mutex_lock (&mutex->mutex);
  g_system_thread_assign (mutex->owner, self);
  mutex->depth = 1;
}

gboolean
g_static_rec_mutex_trylock (GStaticRecMutex* mutex)
{
  GSystemThread self;

  g_return_val_if_fail (mutex, FALSE);

  if (!g_thread_supported ())
    return TRUE;

  G_THREAD_UF (thread_self, (&self));

  if (g_system_thread_equal (self, mutex->owner))
    {
      mutex->depth++;
      return TRUE;
    }

  if (!g_static_mutex_trylock (&mutex->mutex))
    return FALSE;

  g_system_thread_assign (mutex->owner, self);
  mutex->depth = 1;
  return TRUE;
}

void
g_static_rec_mutex_unlock (GStaticRecMutex* mutex)
{
  g_return_if_fail (mutex);

  if (!g_thread_supported ())
    return;

  if (mutex->depth > 1)
    {
      mutex->depth--;
      return;
    }
  g_system_thread_assign (mutex->owner, zero_thread);
  g_static_mutex_unlock (&mutex->mutex);  
}

void
g_static_rec_mutex_lock_full   (GStaticRecMutex *mutex,
				guint            depth)
{
  GSystemThread self;
  g_return_if_fail (mutex);

  if (!g_thread_supported ())
    return;

  G_THREAD_UF (thread_self, (&self));

  if (g_system_thread_equal (self, mutex->owner))
    {
      mutex->depth += depth;
      return;
    }
  g_static_mutex_lock (&mutex->mutex);
  g_system_thread_assign (mutex->owner, self);
  mutex->depth = depth;
}

guint    
g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex)
{
  guint depth;

  g_return_val_if_fail (mutex, 0);

  if (!g_thread_supported ())
    return 1;

  depth = mutex->depth;

  g_system_thread_assign (mutex->owner, zero_thread);
  mutex->depth = 0;
  g_static_mutex_unlock (&mutex->mutex);

  return depth;
}

void
g_static_rec_mutex_free (GStaticRecMutex *mutex)
{
  g_return_if_fail (mutex);

  g_static_mutex_free (&mutex->mutex);
}

void     
g_static_private_init (GStaticPrivate *private_key)
{
  private_key->index = 0;
}

gpointer
g_static_private_get (GStaticPrivate *private_key)
{
  GRealThread *self = (GRealThread*) g_thread_self ();
  GArray *array;

  array = self->private_data;
  if (!array)
    return NULL;

  if (!private_key->index)
    return NULL;
  else if (private_key->index <= array->len)
    return g_array_index (array, GStaticPrivateNode, 
			  private_key->index - 1).data;
  else
    return NULL;
}

void
g_static_private_set (GStaticPrivate *private_key, 
		      gpointer        data,
		      GDestroyNotify  notify)
{
  GRealThread *self = (GRealThread*) g_thread_self ();
  GArray *array;
  static guint next_index = 0;
  GStaticPrivateNode *node;

  array = self->private_data;
  if (!array)
    {
      array = g_array_new (FALSE, TRUE, sizeof (GStaticPrivateNode));
      self->private_data = array;
    }

  if (!private_key->index)
    {
      G_LOCK (g_thread);

      if (!private_key->index)
	{
	  if (g_thread_free_indeces)
	    {
	      private_key->index = 
		GPOINTER_TO_UINT (g_thread_free_indeces->data);
	      g_thread_free_indeces = 
		g_slist_delete_link (g_thread_free_indeces,
				     g_thread_free_indeces);
	    }
	  else
	    private_key->index = ++next_index;
	}

      G_UNLOCK (g_thread);
    }

  if (private_key->index > array->len)
    g_array_set_size (array, private_key->index);

  node = &g_array_index (array, GStaticPrivateNode, private_key->index - 1);
  if (node->destroy)
    {