add ydb deps

1 files changed, 62 insertions, 0 deletions

diff --git a/contrib/python/ipython/py3/IPython/terminal/pt_inputhooks/asyncio.py b/contrib/python/ipython/py3/IPython/terminal/pt_inputhooks/asyncio.py
new file mode 100644
index 0000000000..d2499e11e6
--- /dev/null
+++ b/contrib/python/ipython/py3/IPython/terminal/pt_inputhooks/asyncio.py
@@ -0,0 +1,62 @@
+"""
+Inputhook for running the original asyncio event loop while we're waiting for
+input.
+
+By default, in IPython, we run the prompt with a different asyncio event loop,
+because otherwise we risk that people are freezing the prompt by scheduling bad
+coroutines. E.g., a coroutine that does a while/true and never yield back
+control to the loop. We can't cancel that.
+
+However, sometimes we want the asyncio loop to keep running while waiting for
+a prompt.
+
+The following example will print the numbers from 1 to 10 above the prompt,
+while we are waiting for input. (This works also because we use
+prompt_toolkit`s `patch_stdout`)::
+
+    In [1]: import asyncio
+
+    In [2]: %gui asyncio
+
+    In [3]: async def f():
+       ...:     for i in range(10):
+       ...:         await asyncio.sleep(1)
+       ...:         print(i)
+
+
+    In [4]: asyncio.ensure_future(f())
+
+"""
+from prompt_toolkit import __version__ as ptk_version
+
+from IPython.core.async_helpers import get_asyncio_loop
+
+PTK3 = ptk_version.startswith("3.")
+
+
+def inputhook(context):
+    """
+    Inputhook for asyncio event loop integration.
+    """
+    # For prompt_toolkit 3.0, this input hook literally doesn't do anything.
+    # The event loop integration here is implemented in `interactiveshell.py`
+    # by running the prompt itself in the current asyncio loop. The main reason
+    # for this is that nesting asyncio event loops is unreliable.
+    if PTK3:
+        return
+
+    # For prompt_toolkit 2.0, we can run the current asyncio event loop,
+    # because prompt_toolkit 2.0 uses a different event loop internally.
+
+    # get the persistent asyncio event loop
+    loop = get_asyncio_loop()
+
+    def stop():
+        loop.stop()
+
+    fileno = context.fileno()
+    loop.add_reader(fileno, stop)
+    try:
+        loop.run_forever()
+    finally:
+        loop.remove_reader(fileno)