Merge packages asynchronously in Portage.

pym/_emerge/PackageMerge.py

 # Copyright 1999-2009 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
 
 from _emerge.AsynchronousTask import AsynchronousTask
 from portage.output import colorize
 class PackageMerge(AsynchronousTask):
-        """
-        TODO: Implement asynchronous merge so that the scheduler can
-        run while a merge is executing.
-        """
-
         __slots__ = ("merge",)
 
         def _start(self):
 
                 pkg = self.merge.pkg
                 pkg_count = self.merge.pkg_count
 
                 if pkg.installed:
                         action_desc = "Uninstalling"
                         preposition = "from"
@@ skipping 11 matching lines @@
                         colorize("GOOD", pkg.cpv))
 
                 if pkg.root != "/":
                         msg += " %s %s" % (preposition, pkg.root)
 
                 if not self.merge.build_opts.fetchonly and \
                         not self.merge.build_opts.pretend and \
                         not self.merge.build_opts.buildpkgonly:
                         self.merge.statusMessage(msg)
 
-                self.returncode = self.merge.merge()
-                self.wait()
+                self.merge.merge(self.exit_handler)
 
+        def exit_handler(self, task):
+                self.returncode = task.returncode
+                self._wait_hook()
+