Import Upstream version 2.72.4

glib/tests/once.c

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+
+/* Unit tests for GOnce and friends
+ * Copyright (C) 2011 Red Hat, Inc
+ * Author: Matthias Clasen
+ *
+ * This work is provided "as is"; redistribution and modification
+ * in whole or in part, in any medium, physical or electronic is
+ * permitted without restriction.
+ *
+ * This work 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.
+ *
+ * In no event shall the authors or contributors be liable for any
+ * direct, indirect, incidental, special, exemplary, or consequential
+ * damages (including, but not limited to, procurement of substitute
+ * goods or services; loss of use, data, or profits; or business
+ * interruption) however caused and on any theory of liability, whether
+ * in contract, strict liability, or tort (including negligence or
+ * otherwise) arising in any way out of the use of this software, even
+ * if advised of the possibility of such damage.
+ */
+
+#include <glib.h>
+
+#if GLIB_SIZEOF_VOID_P > 4
+#define THREADS 1000
+#else
+#define THREADS 100
+#endif
+
+static gpointer
+do_once (gpointer data)
+{
+  static gint i = 0;
+
+  i++;
+
+  return GINT_TO_POINTER (i);
+}
+
+static void
+test_once_single_threaded (void)
+{
+  GOnce once = G_ONCE_INIT;
+  gpointer res;
+
+  g_test_summary ("Test g_once() usage from a single thread");
+
+  g_assert (once.status == G_ONCE_STATUS_NOTCALLED);
+
+  res = g_once (&once, do_once, NULL);
+  g_assert_cmpint (GPOINTER_TO_INT (res), ==, 1);
+
+  g_assert (once.status == G_ONCE_STATUS_READY);
+
+  res = g_once (&once, do_once, NULL);
+  g_assert_cmpint (GPOINTER_TO_INT (res), ==, 1);
+}
+
+static GOnce once_multi_threaded = G_ONCE_INIT;
+static gint once_multi_threaded_counter = 0;
+static GCond once_multi_threaded_cond;
+static GMutex once_multi_threaded_mutex;
+static guint once_multi_threaded_n_threads_waiting = 0;
+
+static gpointer
+do_once_multi_threaded (gpointer data)
+{
+  gint old_value;
+
+  /* While this function should only ever be executed once, by one thread,
+   * we should use atomics to ensure that if there were a bug, writes to
+   * `once_multi_threaded_counter` from multiple threads would not get lost and
+   * mean the test erroneously succeeded. */
+  old_value = g_atomic_int_add (&once_multi_threaded_counter, 1);
+
+  return GINT_TO_POINTER (old_value + 1);
+}
+
+static gpointer
+once_thread_func (gpointer data)
+{
+  gpointer res;
+  guint n_threads_expected = GPOINTER_TO_UINT (data);
+
+  /* Don’t immediately call g_once(), otherwise the first thread to be created
+   * will end up calling the once-function, and there will be very little
+   * contention. */
+  g_mutex_lock (&once_multi_threaded_mutex);
+
+  once_multi_threaded_n_threads_waiting++;
+  g_cond_broadcast (&once_multi_threaded_cond);
+
+  while (once_multi_threaded_n_threads_waiting < n_threads_expected)
+    g_cond_wait (&once_multi_threaded_cond, &once_multi_threaded_mutex);
+  g_mutex_unlock (&once_multi_threaded_mutex);
+
+  /* Actually run the test. */
+  res = g_once (&once_multi_threaded, do_once_multi_threaded, NULL);
+  g_assert_cmpint (GPOINTER_TO_INT (res), ==, 1);
+
+  return NULL;
+}
+
+static void
+test_once_multi_threaded (void)
+{
+  guint i;
+  GThread *threads[THREADS];
+
+  g_test_summary ("Test g_once() usage from multiple threads");
+
+  for (i = 0; i < G_N_ELEMENTS (threads); i++)
+    threads[i] = g_thread_new ("once-multi-threaded",
+                               once_thread_func,
+                               GUINT_TO_POINTER (G_N_ELEMENTS (threads)));
+
+  /* All threads have started up, so start the test. */
+  g_cond_broadcast (&once_multi_threaded_cond);
+
+  for (i = 0; i < G_N_ELEMENTS (threads); i++)
+    g_thread_join (threads[i]);
+
+  g_assert_cmpint (g_atomic_int_get (&once_multi_threaded_counter), ==, 1);
+}
+
+static void
+test_once_init_single_threaded (void)
+{
+  static gsize init = 0;
+
+  g_test_summary ("Test g_once_init_{enter,leave}() usage from a single thread");
+
+  if (g_once_init_enter (&init))
+    {
+      g_assert (TRUE);
+      g_once_init_leave (&init, 1);
+    }
+
+  g_assert_cmpint (init, ==, 1);
+  if (g_once_init_enter (&init))
+    {
+      g_assert_not_reached ();
+      g_once_init_leave (&init, 2);
+    }
+  g_assert_cmpint (init, ==, 1);
+}
+
+static gint64 shared;
+
+static void
+init_shared (void)
+{
+  static gsize init = 0;
+
+  if (g_once_init_enter (&init))
+    {
+      shared += 42;
+
+      g_once_init_leave (&init, 1);
+    }
+}
+
+static gpointer
+thread_func (gpointer data)
+{
+  init_shared ();
+
+  return NULL;
+}
+
+static void
+test_once_init_multi_threaded (void)
+{
+  gsize i;
+  GThread *threads[THREADS];
+
+  g_test_summary ("Test g_once_init_{enter,leave}() usage from multiple threads");
+
+  shared = 0;
+
+  for (i = 0; i < G_N_ELEMENTS (threads); i++)
+    threads[i] = g_thread_new ("once-init-multi-threaded", thread_func, NULL);
+
+  for (i = 0; i < G_N_ELEMENTS (threads); i++)
+    g_thread_join (threads[i]);
+
+  g_assert_cmpint (shared, ==, 42);
+}
+
+static void
+test_once_init_string (void)
+{
+  static gchar *val;
+
+  g_test_summary ("Test g_once_init_{enter,leave}() usage with a string");
+
+  if (g_once_init_enter (&val))
+    g_once_init_leave (&val, "foo");
+
+  g_assert_cmpstr (val, ==, "foo");
+}
+
+int
+main (int argc, char *argv[])
+{
+  g_test_init (&argc, &argv, NULL);
+
+  g_test_add_func ("/once/single-threaded", test_once_single_threaded);
+  g_test_add_func ("/once/multi-threaded", test_once_multi_threaded);
+  g_test_add_func ("/once-init/single-threaded", test_once_init_single_threaded);
+  g_test_add_func ("/once-init/multi-threaded", test_once_init_multi_threaded);
+  g_test_add_func ("/once-init/string", test_once_init_string);
+
+  return g_test_run ();
+}