distbuild: Move SubprocessEventSource into its own module

Previously it was only available in the distbuild-helper program. Moving
it to its own module means we can test it and reuse it.

This commit also adds a docstring to the class.

Change-Id: Iaf7854048cf0ff463a87894f1f500cdcb6a34d8b

1 files changed, 5 insertions, 75 deletions

diff --git a/distbuild-helper b/distbuild-helper
index d77fcaea..76a39d5f 100755
--- a/distbuild-helper
+++ b/distbuild-helper
@@ -32,78 +32,6 @@ import urlparse
 import distbuild
 
 
-class FileReadable(object):
-
-    def __init__(self, request_id, p, f):
-        self.request_id = request_id
-        self.process = p
-        self.file = f
-
-
-class FileWriteable(object):
-
-    def __init__(self, request_id, p, f):
-        self.request_id = request_id
-        self.process = p
-        self.file = f
-
-
-class SubprocessEventSource(distbuild.EventSource):
-
-    def __init__(self):
-        self.procs = []
-        self.closed = False
-
-    def get_select_params(self):
-        r = []
-        w = []
-        for requst_id, p in self.procs:
-            if p.stdin_contents is not None:
-                w.append(p.stdin)
-            if p.stdout is not None:
-                r.append(p.stdout)
-            if p.stderr is not None:
-                r.append(p.stderr)
-        return r, w, [], None
-
-    def get_events(self, r, w, x):
-        events = []
-
-        for request_id, p in self.procs:
-            if p.stdin in w:
-                events.append(FileWriteable(request_id, p, p.stdin))
-            if p.stdout in r:
-                events.append(FileReadable(request_id, p, p.stdout))
-            if p.stderr in r:
-                events.append(FileReadable(request_id, p, p.stderr))
-
-        return events
-
-    def add(self, request_id, process):
-
-        self.procs.append((request_id, process))
-        distbuild.set_nonblocking(process.stdin)
-        distbuild.set_nonblocking(process.stdout)
-        distbuild.set_nonblocking(process.stderr)
-
-    def remove(self, process):
-        self.procs = [t for t in self.procs if t[1] != process]
-
-    def kill_by_id(self, request_id):
-        logging.debug('SES: Killing all processes for %s', request_id)
-        for id, process in self.procs:
-            if id == request_id:
-                logging.debug('SES: killing %s', repr(process))
-                process.kill()
-
-    def close(self):
-        self.procs = []
-        self.closed = True
-
-    def is_finished(self):
-        return self.closed
-
-
 class HelperMachine(distbuild.StateMachine):
 
     def __init__(self, conn):
@@ -117,7 +45,7 @@ class HelperMachine(distbuild.StateMachine):
         jm = self.jm = distbuild.JsonMachine(self.conn)
         self.mainloop.add_state_machine(jm)
 
-        p = self.procsrc = SubprocessEventSource()
+        p = self.procsrc = distbuild.SubprocessEventSource()
         self.mainloop.add_event_source(p)
 
         self.send_helper_ready(jm)
@@ -125,8 +53,10 @@ class HelperMachine(distbuild.StateMachine):
         spec = [
             ('waiting', jm, distbuild.JsonNewMessage, 'waiting', self.do),
             ('waiting', jm, distbuild.JsonEof, None, self._eofed),
-            ('waiting', p, FileReadable, 'waiting', self._relay_exec_output),
-            ('waiting', p, FileWriteable, 'waiting', self._feed_stdin),
+            ('waiting', p, distbuild.FileReadable, 'waiting',
+             self._relay_exec_output),
+            ('waiting', p, distbuild.FileWriteable, 'waiting',
+             self._feed_stdin),
         ]
         self.add_transitions(spec)