Sync contrib/tools/python3 layout with upstream

* Move src/ subdir contents to the top of the layout
* Rename self-written lib -> lib2 to avoid CaseFolding warning from the VCS
* Regenerate contrib/libs/python proxy-headers accordingly
4ccc62ac1511abcf0fed14ccade38e984e088f1e

1 files changed, 239 insertions, 0 deletions

diff --git a/contrib/tools/python3/Lib/concurrent/futures/thread.py b/contrib/tools/python3/Lib/concurrent/futures/thread.py
new file mode 100644
index 00000000000..3b3a36a5093
--- /dev/null
+++ b/contrib/tools/python3/Lib/concurrent/futures/thread.py
@@ -0,0 +1,239 @@
+# Copyright 2009 Brian Quinlan. All Rights Reserved.
+# Licensed to PSF under a Contributor Agreement.
+
+"""Implements ThreadPoolExecutor."""
+
+__author__ = 'Brian Quinlan (brian@sweetapp.com)'
+
+from concurrent.futures import _base
+import itertools
+import queue
+import threading
+import types
+import weakref
+import os
+
+
+_threads_queues = weakref.WeakKeyDictionary()
+_shutdown = False
+# Lock that ensures that new workers are not created while the interpreter is
+# shutting down. Must be held while mutating _threads_queues and _shutdown.
+_global_shutdown_lock = threading.Lock()
+
+def _python_exit():
+    global _shutdown
+    with _global_shutdown_lock:
+        _shutdown = True
+    items = list(_threads_queues.items())
+    for t, q in items:
+        q.put(None)
+    for t, q in items:
+        t.join()
+
+# Register for `_python_exit()` to be called just before joining all
+# non-daemon threads. This is used instead of `atexit.register()` for
+# compatibility with subinterpreters, which no longer support daemon threads.
+# See bpo-39812 for context.
+threading._register_atexit(_python_exit)
+
+# At fork, reinitialize the `_global_shutdown_lock` lock in the child process
+if hasattr(os, 'register_at_fork'):
+    os.register_at_fork(before=_global_shutdown_lock.acquire,
+                        after_in_child=_global_shutdown_lock._at_fork_reinit,
+                        after_in_parent=_global_shutdown_lock.release)
+
+
+class _WorkItem:
+    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 as exc:
+            self.future.set_exception(exc)
+            # Break a reference cycle with the exception 'exc'
+            self = None
+        else:
+            self.future.set_result(result)
+
+    __class_getitem__ = classmethod(types.GenericAlias)
+
+
+def _worker(executor_reference, work_queue, initializer, initargs):
+    if initializer is not None:
+        try:
+            initializer(*initargs)
+        except BaseException:
+            _base.LOGGER.critical('Exception in initializer:', exc_info=True)
+            executor = executor_reference()
+            if executor is not None:
+                executor._initializer_failed()
+            return
+    try:
+        while True:
+            try:
+                work_item = work_queue.get_nowait()
+            except queue.Empty:
+                # attempt to increment idle count if queue is empty
+                executor = executor_reference()
+                if executor is not None:
+                    executor._idle_semaphore.release()
+                del executor
+                work_item = work_queue.get(block=True)
+
+            if work_item is not None:
+                work_item.run()
+                # Delete references to object. See GH-60488
+                del work_item
+                continue
+
+            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:
+                # Flag the executor as shutting down as early as possible if it
+                # is not gc-ed yet.
+                if executor is not None:
+                    executor._shutdown = True
+                # Notice other workers
+                work_queue.put(None)
+                return
+            del executor
+    except BaseException:
+        _base.LOGGER.critical('Exception in worker', exc_info=True)
+
+
+class BrokenThreadPool(_base.BrokenExecutor):
+    """
+    Raised when a worker thread in a ThreadPoolExecutor failed initializing.
+    """
+
+
+class ThreadPoolExecutor(_base.Executor):
+
+    # Used to assign unique thread names when thread_name_prefix is not supplied.
+    _counter = itertools.count().__next__
+
+    def __init__(self, max_workers=None, thread_name_prefix='',
+                 initializer=None, initargs=()):
+        """Initializes a new ThreadPoolExecutor instance.
+
+        Args:
+            max_workers: The maximum number of threads that can be used to
+                execute the given calls.
+            thread_name_prefix: An optional name prefix to give our threads.
+            initializer: A callable used to initialize worker threads.
+            initargs: A tuple of arguments to pass to the initializer.
+        """
+        if max_workers is None:
+            # ThreadPoolExecutor is often used to:
+            # * CPU bound task which releases GIL
+            # * I/O bound task (which releases GIL, of course)
+            #
+            # We use cpu_count + 4 for both types of tasks.
+            # But we limit it to 32 to avoid consuming surprisingly large resource
+            # on many core machine.
+            max_workers = min(32, (os.cpu_count() or 1) + 4)
+        if max_workers <= 0:
+            raise ValueError("max_workers must be greater than 0")
+
+        if initializer is not None and not callable(initializer):
+            raise TypeError("initializer must be a callable")
+
+        self._max_workers = max_workers
+        self._work_queue = queue.SimpleQueue()
+        self._idle_semaphore = threading.Semaphore(0)
+        self._threads = set()
+        self._broken = False
+        self._shutdown = False
+        self._shutdown_lock = threading.Lock()
+        self._thread_name_prefix = (thread_name_prefix or
+                                    ("ThreadPoolExecutor-%d" % self._counter()))
+        self._initializer = initializer
+        self._initargs = initargs
+
+    def submit(self, fn, /, *args, **kwargs):
+        with self._shutdown_lock, _global_shutdown_lock:
+            if self._broken:
+                raise BrokenThreadPool(self._broken)
+
+            if self._shutdown:
+                raise RuntimeError('cannot schedule new futures after shutdown')
+            if _shutdown:
+                raise RuntimeError('cannot schedule new futures after '
+                                   'interpreter 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):
+        # if idle threads are available, don't spin new threads
+        if self._idle_semaphore.acquire(timeout=0):
+            return
+
+        # When the executor gets lost, the weakref callback will wake up
+        # the worker threads.
+        def weakref_cb(_, q=self._work_queue):
+            q.put(None)
+
+        num_threads = len(self._threads)
+        if num_threads < self._max_workers:
+            thread_name = '%s_%d' % (self._thread_name_prefix or self,
+                                     num_threads)
+            t = threading.Thread(name=thread_name, target=_worker,
+                                 args=(weakref.ref(self, weakref_cb),
+                                       self._work_queue,
+                                       self._initializer,
+                                       self._initargs))
+            t.start()
+            self._threads.add(t)
+            _threads_queues[t] = self._work_queue
+
+    def _initializer_failed(self):
+        with self._shutdown_lock:
+            self._broken = ('A thread initializer failed, the thread pool '
+                            'is not usable anymore')
+            # Drain work queue and mark pending futures failed
+            while True:
+                try:
+                    work_item = self._work_queue.get_nowait()
+                except queue.Empty:
+                    break
+                if work_item is not None:
+                    work_item.future.set_exception(BrokenThreadPool(self._broken))
+
+    def shutdown(self, wait=True, *, cancel_futures=False):
+        with self._shutdown_lock:
+            self._shutdown = True
+            if cancel_futures:
+                # Drain all work items from the queue, and then cancel their
+                # associated futures.
+                while True:
+                    try:
+                        work_item = self._work_queue.get_nowait()
+                    except queue.Empty:
+                        break
+                    if work_item is not None:
+                        work_item.future.cancel()
+
+            # Send a wake-up to prevent threads calling
+            # _work_queue.get(block=True) from permanently blocking.
+            self._work_queue.put(None)
+        if wait:
+            for t in self._threads:
+                t.join()
+    shutdown.__doc__ = _base.Executor.shutdown.__doc__