[gegl] tests: add test-node-exponential

[N/A <ell src gnome org>]

commit 82fdc8f4e759d2eac07542ac39f737fe8cc2cb09
Author: Ell <ell_se yahoo com>
Date:   Thu Nov 9 18:21:24 2017 -0500

    tests: add test-node-exponential
    
    Add a test case exercising the last two commits, by making sure
    that constructing and invalidating a graph of the form described
    in commit ed8af9caeed516d4f39d3ff2c7337d6959425293 takes a
    reasonable amount of time.

 tests/simple/Makefile.am             |    1 +
 tests/simple/test-node-exponential.c |  124 ++++++++++++++++++++++++++++++++++
 2 files changed, 125 insertions(+), 0 deletions(-)
---
diff --git a/tests/simple/Makefile.am b/tests/simple/Makefile.am
index 3a631db..482f79a 100644
--- a/tests/simple/Makefile.am
+++ b/tests/simple/Makefile.am
@@ -19,6 +19,7 @@ noinst_PROGRAMS =                     \
        test-license-check              \
        test-misc                       \
        test-node-connections           \
+       test-node-exponential           \
        test-node-passthrough           \
        test-node-properties            \
        test-object-forked              \
diff --git a/tests/simple/test-node-exponential.c b/tests/simple/test-node-exponential.c
new file mode 100644
index 0000000..e33dafe
--- /dev/null
+++ b/tests/simple/test-node-exponential.c
@@ -0,0 +1,124 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright (C) 2017 Ell
+ */
+
+/* make sure that graphs of the form
+ *
+ *     ___   ___   ___
+ *    /   v /   v /   v 
+ *   A     B     C     D ...
+ *    \___^ \___^ \___^
+ *
+ * don't lead to an exponential explosion in run time, during
+ * construction and invalidation.
+ *
+ * see commits ed8af9caeed516d4f39d3ff2c7337d6959425293 and
+ * 3d5f4fd38f1b60d5774259062fb64abacf10a7b2.
+ */
+
+#include "config.h"
+
+#include "gegl.h"
+#include "graph/gegl-node-private.h"
+
+#define SUCCESS  0
+#define FAILURE -1
+
+#define TIMEOUT (3 * G_TIME_SPAN_SECOND)
+
+static GMutex            mutex;
+static GCond             cond;
+static volatile gboolean finished = FALSE;
+
+static gpointer
+test (gpointer data)
+{
+  GeglNode *node;
+  GeglNode *input;
+  GeglNode *last;
+  gint      i;
+
+  node = gegl_node_new ();
+
+  input = gegl_node_get_input_proxy (node, "input");
+  last  = input;
+
+  for (i = 0; i < 64; i++)
+    {
+      GeglNode *over;
+
+      over = gegl_node_new_child (node,
+                                  "operation", "gegl:over",
+                                  NULL);
+
+      gegl_node_connect_to (last, "output",
+                            over, "input");
+      gegl_node_connect_to (last, "output",
+                            over, "aux");
+
+      last = over;
+    }
+
+  gegl_node_invalidated (input, NULL, FALSE);
+
+  g_object_unref (node);
+
+  g_mutex_lock (&mutex);
+
+  finished = TRUE;
+  g_cond_signal (&cond);
+
+  g_mutex_unlock (&mutex);
+
+  return NULL;
+}
+
+int main(int argc, char **argv)
+{
+  GThread *thread;
+  gint64   end_time;
+
+  gegl_init (&argc, &argv);
+
+  thread = g_thread_new (NULL, test, NULL);
+
+  end_time = g_get_monotonic_time () + TIMEOUT;
+
+  g_mutex_lock (&mutex);
+
+  while (! finished)
+    {
+      if (! g_cond_wait_until (&cond, &mutex, end_time))
+        break;
+    }
+
+  g_mutex_unlock (&mutex);
+
+  if (finished)
+    {
+      g_thread_join (thread);
+
+      gegl_exit ();
+
+      return SUCCESS;
+    }
+  else
+    {
+      g_print ("timeout expired. failing.\n");
+
+      return FAILURE;
+    }
+}