From 4456682c4c15a288c5a3cb6ee264500eb0bb196c Mon Sep 17 00:00:00 2001
From: Zac Medico <zmedico@gentoo.org>
Date: Sun, 29 Jun 2008 17:27:37 +0000
Subject: Centralize select.poll() event handling in MergeTask._schedule().
 This will allow the parent process to handle output of multiple child
 processes running in parllel.

svn path=/main/trunk/; revision=10851
---
 pym/_emerge/__init__.py | 86 +++++++++++++++++++++++++++----------------------
 1 file changed, 47 insertions(+), 39 deletions(-)

diff --git a/pym/_emerge/__init__.py b/pym/_emerge/__init__.py
index 84b5769a3..8115bdf52 100644
--- a/pym/_emerge/__init__.py
+++ b/pym/_emerge/__init__.py
@@ -20,6 +20,8 @@ try:
 except KeyboardInterrupt:
 	sys.exit(1)
 
+import array
+import select
 import gc
 import os, stat
 import platform
@@ -1527,7 +1529,7 @@ class EbuildBuild(Task):
 	"""
 	TODO: Support asynchronous execution, to implement parallel builds.
 	"""
-	__slots__ = ("pkg", "settings")
+	__slots__ = ("pkg", "register", "schedule", "settings", "unregister")
 
 	_phases = ("setup", "unpack", "compile", "test", "install")
 
@@ -1562,9 +1564,10 @@ class EbuildBuild(Task):
 
 		for mydo in self._phases:
 			ebuild_phase = EbuildPhase(fd_pipes=fd_pipes,
-				pkg=self.pkg, phase=mydo, settings=settings)
+				pkg=self.pkg, phase=mydo, register=self.register,
+				settings=settings, unregister=self.unregister)
 			ebuild_phase.start()
-			ebuild_phase._output_handler()
+			self.schedule()
 			retval = ebuild_phase.wait()
 
 			portage._post_phase_userpriv_perms(settings)
@@ -1580,7 +1583,8 @@ class EbuildBuild(Task):
 
 class EbuildPhase(SlotObject):
 
-	__slots__ = ("fd_pipes", "phase", "pkg", "settings",
+	__slots__ = ("fd_pipes", "phase", "pkg",
+		"register", "settings", "unregister",
 		"pid", "returncode", "files")
 
 	_file_names = ("log", "stdout", "ebuild")
@@ -1662,40 +1666,25 @@ class EbuildPhase(SlotObject):
 			files["log"] = open(logfile, 'a')
 			files["stdout"] = os.fdopen(os.dup(fd_pipes_orig[1]), 'w')
 			files["ebuild"] = os.fdopen(master_fd, 'r')
+			self.register(files["ebuild"].fileno(),
+				select.POLLIN, self._output_handler)
 
-	def _output_handler(self):
-		log_file = self.files.get("log")
-		if log_file is None:
-			return
-		ebuild_file = self.files["ebuild"]
-		stdout_file = self.files["stdout"]
-		iwtd = [ebuild_file]
-		owtd = []
-		ewtd = []
-		import array, select
-		buffsize = self._bufsize
-		eof = False
-		while not eof:
-			events = select.select(iwtd, owtd, ewtd)
-			for f in events[0]:
-				# Use non-blocking mode to prevent read
-				# calls from blocking indefinitely.
-				buf = array.array('B')
-				try:
-					buf.fromfile(f, buffsize)
-				except EOFError:
-					pass
-				if not buf:
-					eof = True
-					break
-				if f is ebuild_file:
-					buf.tofile(stdout_file)
-					stdout_file.flush()
-					buf.tofile(log_file)
-					log_file.flush()
-		log_file.close()
-		stdout_file.close()
-		ebuild_file.close()
+	def _output_handler(self, fd, event):
+		files = self.files
+		buf = array.array('B')
+		try:
+			buf.fromfile(files["ebuild"], self._bufsize)
+		except EOFError:
+			pass
+		if buf:
+			buf.tofile(files["stdout"])
+			files["stdout"].flush()
+			buf.tofile(files["log"])
+			files["log"].flush()
+		else:
+			self.unregister(files["ebuild"].fileno())
+			for f in files.values():
+				f.close()
 
 	def wait(self):
 		pid = self.pid
@@ -6357,6 +6346,8 @@ class MergeTask(object):
 				clone=trees[root]["vartree"].settings)
 		self.curval = 0
 		self._spawned_pids = []
+		self._poll_event_handlers = {}
+		self._poll = select.poll()
 
 	class _pkg_failure(portage.exception.PortageException):
 		"""
@@ -6521,6 +6512,19 @@ class MergeTask(object):
 				pass
 			spawned_pids.remove(pid)
 
+	def _register(self, f, eventmask, handler):
+		self._poll_event_handlers[f] = handler
+		self._poll.register(f, eventmask)
+
+	def _unregister(self, f):
+		self._poll.unregister(f)
+		del self._poll_event_handlers[f]
+
+	def _schedule(self):
+		while self._poll_event_handlers:
+			for f, event in self._poll.poll():
+				self._poll_event_handlers[f](f, event)
+
 	def _merge(self):
 		mylist = self._mergelist
 		favorites = self._favorites
@@ -6759,7 +6763,9 @@ class MergeTask(object):
 							(mergecount, len(mymergelist), pkg_key)
 						emergelog(xterm_titles, msg, short_msg=short_msg)
 
-						build = EbuildBuild(pkg=pkg, settings=pkgsettings)
+						build = EbuildBuild(pkg=pkg, register=self._register,
+							schedule=self._schedule, settings=pkgsettings,
+							unregister=self._unregister)
 						retval = build.execute()
 						if retval != os.EX_OK:
 							raise self._pkg_failure(retval)
@@ -6794,7 +6800,9 @@ class MergeTask(object):
 							(mergecount, len(mymergelist), pkg_key)
 						emergelog(xterm_titles, msg, short_msg=short_msg)
 
-						build = EbuildBuild(pkg=pkg, settings=pkgsettings)
+						build = EbuildBuild(pkg=pkg, register=self._register,
+							schedule=self._schedule, settings=pkgsettings,
+							unregister=self._unregister)
 						retval = build.execute()
 						if retval != os.EX_OK:
 							raise self._pkg_failure(retval)
-- 
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