gateway_base: remove execmodel.{WorkerPool,PopenPiped}

`execmodel.WorkerPool` creates an unneeded dependency cycle. And it's
not any better than the alternative really.

`execmodel.PopenPiped` is a convenience that's not really needed at the
abstraction layer, clearer to just inline it to the one place it's used.

Author: bluetech

execnet/gateway_base.py

@@ -117,9 +117,6 @@ def __getattr__(self, name):
         def fdopen(self, fd, mode, bufsize=1):
             return self._fdopen(fd, mode, bufsize)
 
-        def WorkerPool(self, hasprimary=False):
-            return WorkerPool(self, hasprimary=hasprimary)
-
         def Semaphore(self, size=None):
             if size is None:
                 return EmptySemaphore()
@@ -134,10 +131,6 @@ def RLock(self):
         def Event(self):
             return self._event.Event()
 
-        def PopenPiped(self, args):
-            PIPE = self.subprocess.PIPE
-            return self.subprocess.Popen(args, stdout=PIPE, stdin=PIPE)
-
     return ExecModel(backend)
 
 
@@ -909,7 +902,7 @@ def __init__(self, io, id, _startcount=2):
         # globals may be NONE at process-termination
         self.__trace = trace
         self._geterrortext = geterrortext
-        self._receivepool = self.execmodel.WorkerPool()
+        self._receivepool = WorkerPool(self.execmodel)
 
     def _trace(self, *msg):
         self.__trace(self.id, *msg)
@@ -1011,7 +1004,7 @@ def trace(msg):
             self._trace("[serve] " + msg)
 
         hasprimary = self.execmodel.backend == "thread"
-        self._execpool = self.execmodel.WorkerPool(hasprimary=hasprimary)
+        self._execpool = WorkerPool(self.execmodel, hasprimary=hasprimary)
         trace("spawning receiver thread")
         self._initreceive()
         try:

execnet/gateway_io.py

@@ -17,7 +17,8 @@
 
 class Popen2IOMaster(Popen2IO):
     def __init__(self, args, execmodel):
-        self.popen = p = execmodel.PopenPiped(args)
+        PIPE = execmodel.subprocess.PIPE
+        self.popen = p = execmodel.subprocess.Popen(args, stdout=PIPE, stdin=PIPE)
         super().__init__(p.stdin, p.stdout, execmodel=execmodel)
 
     def wait(self):

execnet/multi.py

@@ -12,6 +12,7 @@
 from . import gateway_io
 from .gateway_base import get_execmodel
 from .gateway_base import trace
+from .gateway_base import WorkerPool
 from .xspec import XSpec
 
 NO_ENDMARKER_WANTED = object()
@@ -292,7 +293,7 @@ def waitclose(self):
 
 
 def safe_terminate(execmodel, timeout, list_of_paired_functions):
-    workerpool = execmodel.WorkerPool()
+    workerpool = WorkerPool(execmodel)
 
     def termkill(termfunc, killfunc):
         termreply = workerpool.spawn(termfunc)