From 684e0f9fa1ed5039dc51e7854bd9cb318a2eaafe Mon Sep 17 00:00:00 2001
From: Zac Medico <zmedico@gentoo.org>
Date: Thu, 27 Dec 2012 00:15:22 -0800
Subject: Add PipeReaderBlockingIO, Jython experimentation.

---
 pym/portage/util/_async/PipeReaderBlockingIO.py | 87 +++++++++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 pym/portage/util/_async/PipeReaderBlockingIO.py

(limited to 'pym/portage/util/_async')

diff --git a/pym/portage/util/_async/PipeReaderBlockingIO.py b/pym/portage/util/_async/PipeReaderBlockingIO.py
new file mode 100644
index 000000000..8ce2ec51b
--- /dev/null
+++ b/pym/portage/util/_async/PipeReaderBlockingIO.py
@@ -0,0 +1,87 @@
+# Copyright 2012 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+import threading
+
+from portage import os
+from _emerge.AbstractPollTask import AbstractPollTask
+
+class PipeReaderBlockingIO(AbstractPollTask):
+	"""
+	Reads output from one or more files and saves it in memory, for
+	retrieval via the getvalue() method. This is driven by a thread
+	for each input file, in order to support blocking IO.  This may
+	be useful for using threads to handle blocking IO with Jython,
+	since Jython lacks the fcntl module which is needed for
+	non-blocking IO (see http://bugs.jython.org/issue1074).
+	"""
+
+	__slots__ = ("input_files", "_read_data", "_terminate",
+		"_threads", "_thread_rlock")
+
+	def _start(self):
+		self._terminate = threading.Event()
+		self._threads = {}
+		self._read_data = []
+
+		self._registered = True
+		self._thread_rlock = threading.RLock()
+		with self._thread_rlock:
+			for f in self.input_files.values():
+				t = threading.Thread(target=self._reader_thread, args=(f,))
+				t.daemon = True
+				t.start()
+				self._threads[f] = t
+
+	def _reader_thread(self, f):
+		try:
+			terminated = self._terminate.is_set
+		except AttributeError:
+			# Jython 2.7.0a2
+			terminated = self._terminate.isSet
+		bufsize = self._bufsize
+		while not terminated():
+			buf = f.read(bufsize)
+			with self._thread_rlock:
+				if terminated():
+					break
+				elif buf:
+					self._read_data.append(buf)
+				else:
+					del self._threads[f]
+					if not self._threads:
+						# Thread-safe callback to EventLoop
+						self.scheduler.idle_add(self._eof)
+					break
+		f.close()
+
+	def _eof(self):
+		self._registered = False
+		if self.returncode is None:
+			self.returncode = os.EX_OK
+		self.wait()
+		return False
+
+	def _cancel(self):
+		self._terminate.set()
+		self._registered = False
+		if self.returncode is None:
+			self.returncode = self._cancelled_returncode
+		self.wait()
+
+	def _wait(self):
+		if self.returncode is not None:
+			return self.returncode
+		self._wait_loop()
+		self.returncode = os.EX_OK
+		return self.returncode
+
+	def getvalue(self):
+		"""Retrieve the entire contents"""
+		with self._thread_rlock:
+			return b''.join(self._read_data)
+
+	def close(self):
+		"""Free the memory buffer."""
+		with self._thread_rlock:
+			self._read_data = None
-- 
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