Re-organize directory structure (#4971)

See discussion in #2491

Co-authored-by: Ivan Levkivskyi <ilevkivskyi@dropbox.com>

stdlib/asyncio/locks.pyi

@@ -0,0 +1,68 @@
+import sys
+from types import TracebackType
+from typing import Any, Awaitable, Callable, Deque, Generator, Optional, Type, TypeVar, Union
+
+from .events import AbstractEventLoop
+from .futures import Future
+
+_T = TypeVar("_T")
+
+if sys.version_info >= (3, 9):
+    class _ContextManagerMixin:
+        def __init__(self, lock: Union[Lock, Semaphore]) -> None: ...
+        def __aenter__(self) -> Awaitable[None]: ...
+        def __aexit__(
+            self, exc_type: Optional[Type[BaseException]], exc: Optional[BaseException], tb: Optional[TracebackType]
+        ) -> Awaitable[None]: ...
+
+else:
+    class _ContextManager:
+        def __init__(self, lock: Union[Lock, Semaphore]) -> None: ...
+        def __enter__(self) -> object: ...
+        def __exit__(self, *args: Any) -> None: ...
+    class _ContextManagerMixin:
+        def __init__(self, lock: Union[Lock, Semaphore]) -> None: ...
+        # Apparently this exists to *prohibit* use as a context manager.
+        def __enter__(self) -> object: ...
+        def __exit__(self, *args: Any) -> None: ...
+        def __iter__(self) -> Generator[Any, None, _ContextManager]: ...
+        def __await__(self) -> Generator[Any, None, _ContextManager]: ...
+        def __aenter__(self) -> Awaitable[None]: ...
+        def __aexit__(
+            self, exc_type: Optional[Type[BaseException]], exc: Optional[BaseException], tb: Optional[TracebackType]
+        ) -> Awaitable[None]: ...
+
+class Lock(_ContextManagerMixin):
+    def __init__(self, *, loop: Optional[AbstractEventLoop] = ...) -> None: ...
+    def locked(self) -> bool: ...
+    async def acquire(self) -> bool: ...
+    def release(self) -> None: ...
+
+class Event:
+    def __init__(self, *, loop: Optional[AbstractEventLoop] = ...) -> None: ...
+    def is_set(self) -> bool: ...
+    def set(self) -> None: ...
+    def clear(self) -> None: ...
+    async def wait(self) -> bool: ...
+
+class Condition(_ContextManagerMixin):
+    def __init__(self, lock: Optional[Lock] = ..., *, loop: Optional[AbstractEventLoop] = ...) -> None: ...
+    def locked(self) -> bool: ...
+    async def acquire(self) -> bool: ...
+    def release(self) -> None: ...
+    async def wait(self) -> bool: ...
+    async def wait_for(self, predicate: Callable[[], _T]) -> _T: ...
+    def notify(self, n: int = ...) -> None: ...
+    def notify_all(self) -> None: ...
+
+class Semaphore(_ContextManagerMixin):
+    _value: int
+    _waiters: Deque[Future[Any]]
+    def __init__(self, value: int = ..., *, loop: Optional[AbstractEventLoop] = ...) -> None: ...
+    def locked(self) -> bool: ...
+    async def acquire(self) -> bool: ...
+    def release(self) -> None: ...
+    def _wake_up_next(self) -> None: ...
+
+class BoundedSemaphore(Semaphore):
+    def __init__(self, value: int = ..., *, loop: Optional[AbstractEventLoop] = ...) -> None: ...