sain.futures

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 30"""Abstractions for threading / asynchronous programming."""
 31
 32from __future__ import annotations
 33
 34__all__ = ("join", "loop")
 35
 36import asyncio
 37import enum
 38import typing
 39
 40from . import result as _result
 41
 42if typing.TYPE_CHECKING:
 43    import collections.abc as collections
 44
 45    T_co = typing.TypeVar("T_co", covariant=True)
 46    T = typing.TypeVar("T", bound=collections.Callable[..., typing.Any])
 47
 48
 49class JoinError(enum.Enum):
 50    EMPTY = 0
 51    """No awaitables were passed."""
 52    CANCELED = 1
 53    """The future gatherer were canceled."""
 54    TIMEOUT = 2
 55    """The future gatherer timed-out."""
 56
 57
 58async def join(
 59    *aws: collections.Awaitable[T_co],
 60    timeout: float | None = None,
 61) -> _result.Result[collections.Sequence[T_co], JoinError]:
 62    """Polls multiple awaitables concurrently, returning a sequence of their results once complete.
 63
 64    Example
 65    -------
 66    ```py
 67    async def one() -> int:
 68        return 1
 69
 70    async def two() -> int:
 71        return 2
 72
 73    x, y = (await join(one(), two())).unwrap()
 74    ```
 75
 76    Parameters
 77    ----------
 78    *aws : `collections.Awaitable[T]`
 79        The awaitables to gather.
 80    timeout : `float | None`
 81        An optional timeout.
 82
 83    Returns
 84    -------
 85    `sain.Result[T, JoinError]`:
 86        The result of the gathered awaitables.
 87    """
 88
 89    if not aws:
 90        return _result.Err(JoinError.EMPTY)
 91
 92    tasks: list[asyncio.Task[T_co]] = []
 93
 94    tasks.extend(asyncio.ensure_future(coro) for coro in aws)
 95    gatherer = asyncio.gather(*tasks)
 96    try:
 97        return _result.Ok(await asyncio.wait_for(gatherer, timeout=timeout))
 98
 99    except asyncio.CancelledError:
100        return _result.Err(JoinError.CANCELED)
101    except asyncio.TimeoutError:
102        return _result.Err(JoinError.TIMEOUT)
103
104    finally:
105        for task in tasks:
106            if not task.done() and not task.cancelled():
107                task.cancel()
108        gatherer.cancel()
109
110
111# source: hikari-py/aio.py
112def loop() -> asyncio.AbstractEventLoop:
113    """Get the current usable event loop or create a new one.
114
115    Returns
116    -------
117    `asyncio.AbstractEventLoop`
118    """
119    try:
120        loop = asyncio.get_event_loop_policy().get_event_loop()
121
122        if not loop.is_closed():
123            return loop
124
125    except RuntimeError:
126        pass
127
128    loop = asyncio.new_event_loop()
129    asyncio.set_event_loop(loop)
130    return loop