Revert the switch to futures for now

Without it, we get random hangs on parse failure. With it, some folks have
seen hangs even on successful cases. The former is clearly less problematic.
This is temporary, until I can finish investigating the root causes of both
issues.

(Bitbake rev: db689a99beffea1a285cdfc74a58fe73f1666987)

Signed-off-by: Christopher Larson <kergoth@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 0 insertions, 144 deletions

diff --git a/bitbake/lib/concurrent/futures/thread.py b/bitbake/lib/concurrent/futures/thread.py
deleted file mode 100644
index ce0dda0c38..0000000000
--- a/bitbake/lib/concurrent/futures/thread.py
+++ /dev/null
@@ -1,144 +0,0 @@
-# Copyright 2009 Brian Quinlan. All Rights Reserved.
-# Licensed to PSF under a Contributor Agreement.
-
-"""Implements ThreadPoolExecutor."""
-
-from __future__ import with_statement
-import atexit
-import threading
-import weakref
-import sys
-
-from concurrent.futures import _base
-
-try:
-    import queue
-except ImportError:
-    import Queue as queue
-
-__author__ = 'Brian Quinlan (brian@sweetapp.com)'
-
-# Workers are created as daemon threads. This is done to allow the interpreter
-# to exit when there are still idle threads in a ThreadPoolExecutor's thread
-# pool (i.e. shutdown() was not called). However, allowing workers to die with
-# the interpreter has two undesirable properties:
-#   - The workers would still be running during interpretor shutdown,
-#     meaning that they would fail in unpredictable ways.
-#   - The workers could be killed while evaluating a work item, which could
-#     be bad if the callable being evaluated has external side-effects e.g.
-#     writing to a file.
-#
-# To work around this problem, an exit handler is installed which tells the
-# workers to exit when their work queues are empty and then waits until the
-# threads finish.
-
-_thread_references = set()
-_shutdown = False
-
-def _python_exit():
-    global _shutdown
-    _shutdown = True
-    for thread_reference in _thread_references:
-        thread = thread_reference()
-        if thread is not None:
-            thread.join()
-
-def _remove_dead_thread_references():
-    """Remove inactive threads from _thread_references.
-
-    Should be called periodically to prevent memory leaks in scenarios such as:
-    >>> while True:
-    ...    t = ThreadPoolExecutor(max_workers=5)
-    ...    t.map(int, ['1', '2', '3', '4', '5'])
-    """
-    for thread_reference in set(_thread_references):
-        if thread_reference() is None:
-            _thread_references.discard(thread_reference)
-
-atexit.register(_python_exit)
-
-class _WorkItem(object):
-    def __init__(self, future, fn, args, kwargs):
-        self.future = future
-        self.fn = fn
-        self.args = args
-        self.kwargs = kwargs
-
-    def run(self):
-        if not self.future.set_running_or_notify_cancel():
-            return
-
-        try:
-            result = self.fn(*self.args, **self.kwargs)
-        except BaseException:
-            e = sys.exc_info()[1]
-            self.future.set_exception(e)
-        else:
-            self.future.set_result(result)
-
-def _worker(executor_reference, work_queue):
-    try:
-        while True:
-            try:
-                work_item = work_queue.get(block=True, timeout=0.1)
-            except queue.Empty:
-                executor = executor_reference()
-                # Exit if:
-                #   - The interpreter is shutting down OR
-                #   - The executor that owns the worker has been collected OR
-                #   - The executor that owns the worker has been shutdown.
-                if _shutdown or executor is None or executor._shutdown:
-                    return
-                del executor
-            else:
-                work_item.run()
-    except BaseException:
-        _base.LOGGER.critical('Exception in worker', exc_info=True)
-
-class ThreadPoolExecutor(_base.Executor):
-    def __init__(self, max_workers):
-        """Initializes a new ThreadPoolExecutor instance.
-
-        Args:
-            max_workers: The maximum number of threads that can be used to
-                execute the given calls.
-        """
-        _remove_dead_thread_references()
-
-        self._max_workers = max_workers
-        self._work_queue = queue.Queue()
-        self._threads = set()
-        self._shutdown = False
-        self._shutdown_lock = threading.Lock()
-
-    def submit(self, fn, *args, **kwargs):
-        with self._shutdown_lock:
-            if self._shutdown:
-                raise RuntimeError('cannot schedule new futures after shutdown')
-
-            f = _base.Future()
-            w = _WorkItem(f, fn, args, kwargs)
-
-            self._work_queue.put(w)
-            self._adjust_thread_count()
-            return f
-    submit.__doc__ = _base.Executor.submit.__doc__
-
-    def _adjust_thread_count(self):
-        # TODO(bquinlan): Should avoid creating new threads if there are more
-        # idle threads than items in the work queue.
-        if len(self._threads) < self._max_workers:
-            t = threading.Thread(target=_worker,
-                                 args=(weakref.ref(self), self._work_queue))
-            t.daemon = True
-            t.start()
-            self._threads.add(t)
-            _thread_references.add(weakref.ref(t))
-
-    def shutdown(self, wait=True):
-        with self._shutdown_lock:
-            self._shutdown = True
-        if wait:
-            for t in self._threads:
-                t.join()
-    shutdown.__doc__ = _base.Executor.shutdown.__doc__