[glib] tests/mainloop: add a test for child sources

[Dan Winship <danw src gnome org>]

commit bdbb5313408013d0877aa76352fa4a14015841c5
Author: Dan Winship <danw gnome org>
Date:   Fri Apr 13 11:44:34 2012 -0400

    tests/mainloop: add a test for child sources
    
    https://bugzilla.gnome.org/show_bug.cgi?id=669260

 glib/tests/mainloop.c |   98 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 98 insertions(+), 0 deletions(-)
---
diff --git a/glib/tests/mainloop.c b/glib/tests/mainloop.c
index 4d27985..8c2f2c5 100644
--- a/glib/tests/mainloop.c
+++ b/glib/tests/mainloop.c
@@ -312,6 +312,103 @@ test_invoke (void)
   g_assert_cmpint (count, ==, 3);
 }
 
+static gboolean
+run_inner_loop (gpointer user_data)
+{
+  GMainContext *ctx = user_data;
+  GMainLoop *inner;
+  GSource *timeout;
+
+  a++;
+
+  inner = g_main_loop_new (ctx, FALSE);
+  timeout = g_timeout_source_new (100);
+  g_source_set_callback (timeout, (GSourceFunc)g_main_loop_quit, inner, NULL);
+  g_source_attach (timeout, ctx);
+
+  g_main_loop_run (inner);
+  g_main_loop_unref (inner);
+
+  return TRUE;
+}
+
+static void
+test_child_sources (void)
+{
+  GMainContext *ctx;
+  GMainLoop *loop;
+  GSource *parent, *child_b, *child_c, *end;
+
+  ctx = g_main_context_new ();
+  loop = g_main_loop_new (ctx, FALSE);
+
+  a = b = c = 0;
+
+  parent = g_timeout_source_new (2000);
+  g_source_set_callback (parent, run_inner_loop, ctx, NULL);
+  g_source_set_priority (parent, G_PRIORITY_LOW);
+  g_source_attach (parent, ctx);
+
+  child_b = g_timeout_source_new (250);
+  g_source_set_callback (child_b, count_calls, &b, NULL);
+  g_source_add_child_source (parent, child_b);
+
+  child_c = g_timeout_source_new (330);
+  g_source_set_callback (child_c, count_calls, &c, NULL);
+  g_source_set_priority (child_c, G_PRIORITY_HIGH);
+  g_source_add_child_source (parent, child_c);
+
+  /* Child sources always have the priority of the parent */
+  g_assert_cmpint (g_source_get_priority (parent), ==, G_PRIORITY_LOW);
+  g_assert_cmpint (g_source_get_priority (child_b), ==, G_PRIORITY_LOW);
+  g_assert_cmpint (g_source_get_priority (child_c), ==, G_PRIORITY_LOW);
+  g_source_set_priority (parent, G_PRIORITY_DEFAULT);
+  g_assert_cmpint (g_source_get_priority (parent), ==, G_PRIORITY_DEFAULT);
+  g_assert_cmpint (g_source_get_priority (child_b), ==, G_PRIORITY_DEFAULT);
+  g_assert_cmpint (g_source_get_priority (child_c), ==, G_PRIORITY_DEFAULT);
+
+  end = g_timeout_source_new (1050);
+  g_source_set_callback (end, (GSourceFunc)g_main_loop_quit, loop, NULL);
+  g_source_attach (end, ctx);
+  g_source_unref (end);
+
+  g_main_loop_run (loop);
+
+  /* The parent source's own timeout will never trigger, so "a" will
+   * only get incremented when "b" or "c" does. And when timeouts get
+   * blocked, they still wait the full interval next time rather than
+   * "catching up". So the timing is:
+   *
+   *  250 - b++ -> a++, run_inner_loop
+   *  330 - (c is blocked)
+   *  350 - inner_loop ends
+   *  350 - c++ belatedly -> a++, run_inner_loop
+   *  450 - inner loop ends
+   *  500 - b++ -> a++, run_inner_loop
+   *  600 - inner_loop ends
+   *  680 - c++ -> a++, run_inner_loop
+   *  750 - (b is blocked)
+   *  780 - inner loop ends
+   *  780 - b++ belatedly -> a++, run_inner_loop
+   *  880 - inner loop ends
+   * 1010 - c++ -> a++, run_inner_loop
+   * 1030 - (b is blocked)
+   * 1050 - end runs, quits outer loop, which has no effect yet
+   * 1110 - inner loop ends, a returns, outer loop exits
+   */
+
+  g_assert_cmpint (a, ==, 6);
+  g_assert_cmpint (b, ==, 3);
+  g_assert_cmpint (c, ==, 3);
+
+  g_source_unref (parent);
+  g_source_unref (child_b);
+  g_source_unref (child_c);
+
+  g_main_loop_unref (loop);
+  g_main_context_unref (ctx);
+}
+
 int
 main (int argc, char *argv[])
 {
@@ -322,6 +419,7 @@ main (int argc, char *argv[])
   g_test_add_func ("/mainloop/timeouts", test_timeouts);
   g_test_add_func ("/mainloop/priorities", test_priorities);
   g_test_add_func ("/mainloop/invoke", test_invoke);
+  g_test_add_func ("/mainloop/child_sources", test_child_sources);
 
   return g_test_run ();
 }