folder reorganization

lib/urllib3/util/wait.py

@@ -0,0 +1,40 @@
+from .selectors import (
+    HAS_SELECT,
+    DefaultSelector,
+    EVENT_READ,
+    EVENT_WRITE
+)
+
+
+def _wait_for_io_events(socks, events, timeout=None):
+    """ Waits for IO events to be available from a list of sockets
+    or optionally a single socket if passed in. Returns a list of
+    sockets that can be interacted with immediately. """
+    if not HAS_SELECT:
+        raise ValueError('Platform does not have a selector')
+    if not isinstance(socks, list):
+        # Probably just a single socket.
+        if hasattr(socks, "fileno"):
+            socks = [socks]
+        # Otherwise it might be a non-list iterable.
+        else:
+            socks = list(socks)
+    with DefaultSelector() as selector:
+        for sock in socks:
+            selector.register(sock, events)
+        return [key[0].fileobj for key in
+                selector.select(timeout) if key[1] & events]
+
+
+def wait_for_read(socks, timeout=None):
+    """ Waits for reading to be available from a list of sockets
+    or optionally a single socket if passed in. Returns a list of
+    sockets that can be read from immediately. """
+    return _wait_for_io_events(socks, EVENT_READ, timeout)
+
+
+def wait_for_write(socks, timeout=None):
+    """ Waits for writing to be available from a list of sockets
+    or optionally a single socket if passed in. Returns a list of
+    sockets that can be written to immediately. """
+    return _wait_for_io_events(socks, EVENT_WRITE, timeout)