Completed the thread support in GLib. Thread creation, prioritizing

1999-06-17  Sebastian Wilhelmi  <wilhelmi@ira.uka.de>

	* configure.in, acglib.m4, acconfig.h, glib.h, gthread.c:
	Completed the thread support in GLib. Thread creation,
	prioritizing threads, yielding, joining threads as well as
	reader/writer locks and recursive mutexes are now in place. Please
	test heavily on your platform. It is so far tested on
	Linux/i386/pthreads, Solaris/Sparc/pthreads and
	Solaris/Sparc/solaristhreads.

	* gtimer.c, glib.h: Implement g_usleep (gulong microseconds) for
	thread safe sleeping. (sleep() is not MT-safe at all!)

	* gutils.c: Avoid compiler warning.

	* tests/Makefile.am, tests/thread-test.c: New program to test some
	aspects of the thread implementation.

	* gthread.c, Makefile.am: Renamed from gmutex.c to reflect the
	change of content.

	* configure.in: Purged all appearances of nspr.

	* gthread/gthread-posix.c, gthread-solaris.c: Added the native
	implementations for the GLib's extended thread support.

	* gthread/gthread-nspr.c: Removed for good. NSPR is nothing we
	would want to build upon.

	* gthread/gthread.c: Renamed to gthread-impl.c to avoid
	confusion with ../gthread.c (Formerly known as the file called
	gmutex.c)

	* gthread/testgthread.c: Removed. The new and much extended
        tests are in ../tests/thread-test.c.

	* gthread/Makefile.am: Changed to reflect the changes above.

1 files changed, 535 insertions, 0 deletions

diff --git a/gthread.c b/gthread.c
new file mode 100644
index 000000000..0aaef25f1
--- /dev/null
+++ b/gthread.c
@@ -0,0 +1,535 @@
+/* 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 Library 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library 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 1997-1999.  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 "glib.h"
+#include <unistd.h>
+
+typedef struct _GRealThread GRealThread;
+
+struct  _GRealThread
+{
+  GThread thread;
+  GThreadFunc func;
+  gpointer arg;
+  gpointer system_thread;
+  gpointer private_data;
+};
+
+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 */
+
+gboolean g_thread_use_default_impl = TRUE;
+gboolean g_threads_got_initialized = FALSE;
+
+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 */
+  (gpointer(*)(GThreadFunc, gpointer, gulong, 
+	       gboolean, gboolean, 
+	       GThreadPriority))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 GMutex   *g_thread_specific_mutex = NULL;
+static GPrivate *g_thread_specific_private = NULL;
+
+/* 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)
+{
+  gpointer private_old;
+ 
+  /* We let the main thread (the one that calls g_thread_init) inherit
+   * the data, that it set before calling g_thread_init
+   */
+  private_old = g_thread_specific_private;
+
+  g_thread_specific_private = g_private_new (g_thread_cleanup);
+
+  /* we can not use g_private_set here, as g_threads_got_initialized is not
+   * yet set TRUE, whereas the private_set function is already set.
+   */
+  g_thread_functions_for_glib_use.private_set (g_thread_specific_private, 
+					       private_old);
+
+  g_mutex_protect_static_mutex_allocation = g_mutex_new();
+  g_thread_specific_mutex = g_mutex_new();
+  
+}
+
+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;
+}
+
+#ifndef g_static_rec_mutex_lock
+/* That means, that g_static_rec_mutex_lock is not defined to be 
+ * g_static_mutex_lock, we have to provide an implementation ourselves.
+ */
+void
+g_static_rec_mutex_lock (GStaticRecMutex* mutex)
+{
+  guint counter = GPOINTER_TO_UINT (g_static_private_get (&mutex->counter));
+  if (counter == 0)
+    {
+      g_static_mutex_lock (&mutex->mutex);
+    }
+  counter++;
+  g_static_private_set (&mutex->counter, GUINT_TO_POINTER (counter), NULL);
+}
+
+gboolean
+g_static_rec_mutex_trylock (GStaticRecMutex* mutex)
+{
+  guint counter = GPOINTER_TO_UINT (g_static_private_get (&mutex->counter));
+  if (counter == 0)
+    {
+      if (!g_static_mutex_trylock (&mutex->mutex)) return FALSE;
+    }
+  counter++;
+  g_static_private_set (&mutex->counter, GUINT_TO_POINTER (counter), NULL);
+  return TRUE;
+}
+
+void
+g_static_rec_mutex_unlock (GStaticRecMutex* mutex)
+{
+  guint counter = GPOINTER_TO_UINT (g_static_private_get (&mutex->counter));
+  if (counter == 1)
+    {
+      g_static_mutex_unlock (&mutex->mutex);
+    }
+  counter--;
+  g_static_private_set (&mutex->counter, GUINT_TO_POINTER (counter), NULL);
+}
+#endif /* g_static_rec_mutex_lock */
+
+gpointer
+g_static_private_get (GStaticPrivate *private_key)
+{
+  return g_static_private_get_for_thread (private_key, g_thread_self ());
+}
+
+gpointer
+g_static_private_get_for_thread (GStaticPrivate *private_key,
+				 GThread        *thread)
+{
+  GArray *array;
+  GRealThread *self = (GRealThread*) thread;
+
+  g_return_val_if_fail (thread, NULL);
+
+  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)
+{
+  g_static_private_set_for_thread (private_key, g_thread_self (), 
+				   data, notify);
+}
+
+void
+g_static_private_set_for_thread (GStaticPrivate *private_key, 
+				 GThread        *thread,
+				 gpointer        data,
+				 GDestroyNotify  notify)
+{
+  GArray *array;
+  GRealThread *self =(GRealThread*) thread;
+  static guint next_index = 0;
+  GStaticPrivateNode *node;
+
+  g_return_if_fail (thread);
+  
+  array = self->private_data;
+  if (!array)
+    {
+      array = g_array_new (FALSE, TRUE, sizeof (GStaticPrivateNode));
+      self->private_data = array;
+    }
+
+  if (!private_key->index)
+    {
+      g_mutex_lock (g_thread_specific_mutex);
+
+      if (!private_key->index)
+	private_key->index = ++next_index;
+
+      g_mutex_unlock (g_thread_specific_mutex);
+    }
+
+  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)
+    {
+      gpointer ddata = node->data;
+      GDestroyNotify ddestroy = node->destroy;
+
+      node->data = data;
+      node->destroy = notify;
+
+      ddestroy (ddata);
+    }
+  else
+    {
+      node->data = data;
+      node->destroy = notify;
+    }
+}
+
+static void
+g_thread_cleanup (gpointer data)
+{
+  if (data)
+    {
+      GRealThread* thread = data;
+      if (thread->private_data)
+	{
+	  GArray* array = thread->private_data;
+	  guint i;
+	  
+	  for (i = 0; i < array->len; i++ )
+	    {
+	      GStaticPrivateNode *node = 
+		&g_array_index (array, GStaticPrivateNode, i);
+	      if (node->destroy)
+		node->destroy (node->data);
+	    }
+	  g_array_free (array, TRUE);
+	}
+      /* We only free the thread structure, if it isn't joinable. If
+         it is, the structure is freed in g_thread_join */
+      if (!thread->thread.joinable)
+	{
+	  /* Just to make sure, this isn't used any more */
+	  thread->system_thread = NULL;
+	  g_free (thread);
+	}
+    }
+}
+
+static void
+g_thread_fail (void)
+{
+  g_error ("The thread system is not yet initialized.");
+}
+
+G_LOCK_DEFINE_STATIC (g_thread_create);
+
+static void 
+g_thread_create_proxy (gpointer data)
+{
+  GRealThread* thread = data;
+
+  g_assert (data);
+
+  /* the lock makes sure, that thread->system_thread is written,
+     before thread->func is called. See g_thread_create */
+
+  G_LOCK (g_thread_create);
+  g_private_set (g_thread_specific_private, data);
+  G_UNLOCK (g_thread_create);
+
+  thread->func (thread->arg);
+}
+
+GThread* 
+g_thread_create (GThreadFunc 		 thread_func,
+		 gpointer 		 arg,
+		 gulong 		 stack_size,
+		 gboolean 		 joinable,
+		 gboolean 		 bound,
+		 GThreadPriority 	 priority)
+{
+  GRealThread* result = g_new0 (GRealThread,1);
+
+  g_return_val_if_fail (thread_func, NULL);
+  
+  result->thread.joinable = joinable;
+  result->thread.bound = bound;
+  result->thread.priority = priority;
+  result->func = thread_func;
+  result->arg = arg;
+  G_LOCK (g_thread_create);
+  result->system_thread = G_THREAD_UF (thread_create, (g_thread_create_proxy, 
+						       result, stack_size, 
+						       joinable, bound, 
+						       priority));
+  G_UNLOCK (g_thread_create);
+  return (GThread*) result;
+}
+
+void 
+g_thread_join (GThread* thread)
+{
+  GRealThread* real = (GRealThread*) thread;
+
+  g_return_if_fail (thread);
+  g_return_if_fail (thread->joinable);
+  g_return_if_fail (real->system_thread);
+
+  G_THREAD_UF (thread_join, (real->system_thread));
+
+  /* Just to make sure, this isn't used any more */
+  thread->joinable = 0;
+  real->system_thread = NULL;
+
+  /* the thread structure for non-joinable threads is freed upon
+     thread end. We free the memory here. This will leave loose end,
+     if a joinable thread is not joined. */
+
+  g_free (thread);
+}
+
+void
+g_thread_set_priority (GThread* thread, 
+		       GThreadPriority priority)
+{
+  GRealThread* real = (GRealThread*) thread;
+
+  g_return_if_fail (thread);
+  g_return_if_fail (real->system_thread);
+
+  thread->priority = priority;
+  G_THREAD_CF (thread_set_priority, (void)0, (real->system_thread, priority));
+}
+
+GThread*
+g_thread_self()
+{
+  GRealThread* thread = g_private_get (g_thread_specific_private);
+
+  if (!thread)
+    {  
+      /* If no thread data is available, provide and set one.  This
+         can happen for the main thread and for threads, that are not
+         created by glib. */
+      thread = g_new (GRealThread,1);
+      thread->thread.joinable = FALSE; /* This is a save guess */
+      thread->thread.bound = TRUE; /* This isn't important at all */
+      thread->thread.priority = G_THREAD_PRIORITY_NORMAL; /* This is
+							     just a guess */
+      thread->func = NULL;
+      thread->arg = NULL;
+      thread->system_thread = NULL;
+      thread->private_data = NULL;
+      g_private_set (g_thread_specific_private, thread);
+    }
+     
+  if (g_thread_supported () && !thread->system_thread)
+    {
+      thread->system_thread = g_thread_functions_for_glib_use.thread_self();
+    }
+
+  return (GThread*)thread;
+}
+
+static void inline g_static_rw_lock_wait (GCond** cond, GStaticMutex* mutex)
+{
+  if (!*cond)
+      *cond = g_cond_new ();
+  g_cond_wait (*cond, g_static_mutex_get_mutex (mutex));
+}
+
+static void inline g_static_rw_lock_signal (GStaticRWLock* lock)
+{
+  if (lock->want_to_write && lock->write_cond)
+    g_cond_signal (lock->write_cond);
+  else if (lock->read_cond)
+    g_cond_signal (lock->read_cond);
+}
+
+void g_static_rw_lock_reader_lock (GStaticRWLock* lock)
+{
+  g_return_if_fail (lock);
+
+  if (!g_threads_got_initialized)
+    return;
+
+  g_static_mutex_lock (&lock->mutex);
+  while (lock->write || lock->want_to_write) 
+    g_static_rw_lock_wait (&lock->read_cond, &lock->mutex);
+  lock->read_counter++;
+  g_static_mutex_unlock (&lock->mutex);
+}
+
+gboolean g_static_rw_lock_reader_trylock (GStaticRWLock* lock)
+{
+  gboolean ret_val = FALSE;
+
+  g_return_val_if_fail (lock, FALSE);
+
+  if (!g_threads_got_initialized)
+    return TRUE;
+
+  g_static_mutex_lock (&lock->mutex);
+  if (!lock->write && !lock->want_to_write)
+    {
+      lock->read_counter++;
+      ret_val = TRUE;
+    }
+  g_static_mutex_unlock (&lock->mutex);
+  return ret_val;
+}
+
+void g_static_rw_lock_reader_unlock  (GStaticRWLock* lock)
+{
+  g_return_if_fail (lock);
+
+  if (!g_threads_got_initialized)
+    return;
+
+  g_static_mutex_lock (&lock->mutex);
+  lock->read_counter--;
+  g_static_rw_lock_signal (lock);
+  g_static_mutex_unlock (&lock->mutex);
+}
+
+void g_static_rw_lock_writer_lock (GStaticRWLock* lock)
+{
+  g_return_if_fail (lock);
+
+  if (!g_threads_got_initialized)
+    return;
+
+  g_static_mutex_lock (&lock->mutex);
+  lock->want_to_write++;
+  while (lock->write || lock->read_counter)
+    g_static_rw_lock_wait (&lock->write_cond, &lock->mutex);
+  lock->want_to_write--;
+  lock->write = TRUE;
+  g_static_mutex_unlock (&lock->mutex);
+}
+
+gboolean g_static_rw_lock_writer_trylock (GStaticRWLock* lock)
+{
+  gboolean ret_val = FALSE;
+
+  g_return_val_if_fail (lock, FALSE);
+  
+  if (!g_threads_got_initialized)
+    return TRUE;
+
+  g_static_mutex_lock (&lock->mutex);
+  if (!lock->write && !lock->read_counter)
+    {
+      lock->write = TRUE;
+      ret_val = TRUE;
+    }
+  g_static_mutex_unlock (&lock->mutex);
+  return ret_val;
+}
+
+void g_static_rw_lock_writer_unlock (GStaticRWLock* lock)
+{
+  g_return_if_fail (lock);
+  
+  if (!g_threads_got_initialized)
+    return;
+
+  g_static_mutex_lock (&lock->mutex);
+  lock->write = FALSE; 
+  g_static_rw_lock_signal (lock);
+  g_static_mutex_unlock (&lock->mutex);
+}
+
+void g_static_rw_lock_free (GStaticRWLock* lock)
+{
+  g_return_if_fail (lock);
+  
+  if (lock->read_cond)
+    g_cond_free (lock->read_cond);
+  if (lock->write_cond)
+    g_cond_free (lock->write_cond);
+  
+}
+