* Since can_poll_pty() is unsafe due to he possibility of the poll() call

  blocking forever, replace it with a simpler test on /dev/null that's
  derived from a test in a glib2 configure script.

* Remove PtyReaderTestCase since it has the same problem as can_poll_pty().

svn path=/main/trunk/; revision=11039

2 files changed, 27 insertions, 58 deletions

diff --git a/pym/_emerge/__init__.py b/pym/_emerge/__init__.py
index 12cd9c690..e03b57072 100644
--- a/pym/_emerge/__init__.py
+++ b/pym/_emerge/__init__.py
@@ -7974,57 +7974,42 @@ class SequentialTaskQueue(SlotObject):
 	def __len__(self):
 		return len(self._task_queue) + len(self.running_tasks)
 
-_can_poll_pty = None
+_can_poll_device = None
 
-def can_poll_pty():
+def can_poll_device():
 	"""
-	Test if it's possible to use poll() on a pty device. This
+	Test if it's possible to use poll() on a device such as a pty. This
 	is known to fail on Darwin.
 	@rtype: bool
-	@returns: True if poll() on a pty device succeeds, False otherwise.
+	@returns: True if poll() on a device succeeds, False otherwise.
 	"""
 
-	global _can_poll_pty
-	if _can_poll_pty is not None:
-		return _can_poll_pty
+	global _can_poll_device
+	if _can_poll_device is not None:
+		return _can_poll_device
 
 	if not hasattr(select, "poll"):
-		_can_poll_pty = False
-		return _can_poll_pty
+		_can_poll_device = False
+		return _can_poll_device
 
-	got_pty, master_fd, slave_fd = \
-		portage._create_pty_or_pipe(copy_term_size=sys.stdout.fileno())
-	if not got_pty:
-		os.close(master_fd)
-		os.close(slave_fd)
-		_can_poll_pty = False
-		return _can_poll_pty
-
-	test_string = 2 * "blah blah blah\n"
-
-	master_file = os.fdopen(master_fd, 'r')
-
-	task_scheduler = TaskScheduler(max_jobs=2, poll=select.poll())
-	scheduler = task_scheduler.sched_iface
-
-	producer = SpawnProcess(
-		args=["bash", "-c", "echo -n '%s'" % test_string],
-		fd_pipes={1:slave_fd,2:slave_fd}, scheduler=scheduler)
-
-	consumer = PipeReader(
-		input_files={"producer" : master_file},
-		scheduler=scheduler)
-
-	task_scheduler.add(producer)
-	task_scheduler.add(consumer)
-
-	def producer_start_cb(task):
-		os.close(slave_fd)
+	try:
+		dev_null = open('/dev/null', 'rb')
+	except IOError:
+		_can_poll_device = False
+		return _can_poll_device
+
+	p = select.poll()
+	p.register(dev_null.fileno(), PollConstants.POLLIN)
+
+	invalid_request = False
+	for f, event in p.poll():
+		if event & PollConstants.POLLNVAL:
+			invalid_request = True
+			break
+	dev_null.close()
 
-	producer.addStartListener(producer_start_cb)
-	task_scheduler.run()
-	_can_poll_pty = test_string == consumer.getvalue()
-	return _can_poll_pty
+	_can_poll_device = not invalid_request
+	return _can_poll_device
 
 def create_poll_instance():
 	"""
@@ -8032,7 +8017,7 @@ def create_poll_instance():
 	PollSelectAdapter there is no poll() implementation or
 	it is broken somehow.
 	"""
-	if can_poll_pty():
+	if can_poll_device():
 		return select.poll()
 	return PollSelectAdapter()
 
diff --git a/pym/portage/tests/process/test_poll.py b/pym/portage/tests/process/test_poll.py
index 8a52f4577..96749d567 100644
--- a/pym/portage/tests/process/test_poll.py
+++ b/pym/portage/tests/process/test_poll.py
@@ -51,19 +51,3 @@ class PipeReaderTestCase(TestCase):
 		task_scheduler.run()
 
 		self._assertEqual(test_string, consumer.getvalue())
-
-class PtyReaderTestCase(PipeReaderTestCase):
-
-	def _assertEqual(self, test_string, consumer_value):
-		if test_string != consumer_value:
-			# This test is expected to fail on some operating systems
-			# such as Darwin that do not support poll() on pty devices.
-			self.todo = True
-		self.assertEqual(test_string, consumer_value)
-
-	def _create_pipe(self):
-
-		got_pty, master_fd, slave_fd = \
-			portage._create_pty_or_pipe(copy_term_size=sys.stdout.fileno())
-
-		return (master_fd, slave_fd)