1 files changed, 70 insertions, 0 deletions
diff --git a/pym/_emerge/PollSelectAdapter.py b/pym/_emerge/PollSelectAdapter.py
new file mode 100644
index 000000000..d3b9da990
--- /dev/null
+++ b/pym/_emerge/PollSelectAdapter.py
@@ -0,0 +1,70 @@
+from _emerge.PollConstants import PollConstants
+import select
+class PollSelectAdapter(PollConstants):
+
+	"""
+	Use select to emulate a poll object, for
+	systems that don't support poll().
+	"""
+
+	def __init__(self):
+		self._registered = {}
+		self._select_args = [[], [], []]
+
+	def register(self, fd, *args):
+		"""
+		Only POLLIN is currently supported!
+		"""
+		if len(args) > 1:
+			raise TypeError(
+				"register expected at most 2 arguments, got " + \
+				repr(1 + len(args)))
+
+		eventmask = PollConstants.POLLIN | \
+			PollConstants.POLLPRI | PollConstants.POLLOUT
+		if args:
+			eventmask = args[0]
+
+		self._registered[fd] = eventmask
+		self._select_args = None
+
+	def unregister(self, fd):
+		self._select_args = None
+		del self._registered[fd]
+
+	def poll(self, *args):
+		if len(args) > 1:
+			raise TypeError(
+				"poll expected at most 2 arguments, got " + \
+				repr(1 + len(args)))
+
+		timeout = None
+		if args:
+			timeout = args[0]
+
+		select_args = self._select_args
+		if select_args is None:
+			select_args = [self._registered.keys(), [], []]
+
+		if timeout is not None:
+			select_args = select_args[:]
+			# Translate poll() timeout args to select() timeout args:
+			#
+			#          | units        | value(s) for indefinite block
+			# ---------|--------------|------------------------------
+			#   poll   | milliseconds | omitted, negative, or None
+			# ---------|--------------|------------------------------
+			#   select | seconds      | omitted
+			# ---------|--------------|------------------------------
+
+			if timeout is not None and timeout < 0:
+				timeout = None
+			if timeout is not None:
+				select_args.append(timeout / 1000)
+
+		select_events = select.select(*select_args)
+		poll_events = []
+		for fd in select_events[0]:
+			poll_events.append((fd, PollConstants.POLLIN))
+		return poll_events
+