launcher: add valgrind support

Add a --valgrind option to gst-validate-launcher to run the tests inside
Valgrind and tune GLib's memory allocator accordingly.

Fix https://bugzilla.gnome.org/show_bug.cgi?id=746465

validate/launcher/baseclasses.py

@@ -38,6 +38,10 @@ import xml.etree.cElementTree as ET
 from utils import mkdir, Result, Colors, printc, DEFAULT_TIMEOUT, GST_SECOND, \
     Protocols
 
+# The factor by which we increase the hard timeout when running inside
+# Valgrind
+VALGRIND_TIMEOUT_FACTOR = 5
+
 
 class Test(Loggable):
 
@@ -270,6 +274,27 @@ class Test(Loggable):
         if self.result is not Result.TIMEOUT:
             self.queue.put(None)
 
+    def use_valgrind(self):
+        vg_args = [
+            ('trace-children', 'yes'),
+            ('tool', 'memcheck'),
+            ('leak-check', 'full'),
+            ('leak-resolution', 'high'),
+            ('num-callers', '20'),
+        ]
+
+        self.command = "valgrind %s %s" % (' '.join(map(lambda x: '--%s=%s' % (x[0], x[1]), vg_args)),
+                                           self.command)
+
+        # Tune GLib's memory allocator to be more valgrind friendly
+        self.proc_env['G_DEBUG'] = 'gc-friendly'
+        self.add_env_variable('G_DEBUG', 'gc-friendly')
+
+        self.proc_env['G_SLICE'] = 'always-malloc'
+        self.add_env_variable('G_SLICE', 'always-malloc')
+
+        self.hard_timeout *= VALGRIND_TIMEOUT_FACTOR
+
     def test_start(self, queue):
         self.open_logfile()
 
@@ -279,6 +304,9 @@ class Test(Loggable):
         self.build_arguments()
         self.proc_env = self.get_subproc_env()
 
+        if self.options.valgrind:
+            self.use_valgrind()
+
         message = "Launching: %s%s\n" \
                   "    Command: '%s %s'\n" % (Colors.ENDC, self.classname,
                                               self._env_variable, self.command)

validate/launcher/main.py

@@ -217,6 +217,7 @@ class LauncherConfig(Loggable):
         self.generate_info_full = False
         self.long_limit = utils.LONG_TEST
         self.config = None
+        self.valgrind = False
         self.xunit_file = None
         self.main_dir = utils.DEFAULT_MAIN_DIR
         self.output_dir = None
@@ -416,6 +417,9 @@ Note that all testsuite should be inside python modules, so the directory should
     parser.add_argument("-c", "--config", dest="config",
                         help="This is DEPRECATED, prefer using the testsuite format"
                         " to configure testsuites")
+    parser.add_argument("-vg", "--valgrind", dest="valgrind",
+                        action="store_true",
+                        help="Run the tests inside Valgrind")
     dir_group = parser.add_argument_group(
         "Directories and files to be used by the launcher")
     parser.add_argument('--xunit-file', action='store',