#!/usr/bin/env python3
+"""A future that can be treated like the result that it contains and
+will not block until it is used. At that point, if the underlying
+value is not yet available, it will block until it becomes
+available."""
+
from __future__ import annotations
import concurrent
import concurrent.futures as fut
import logging
-import traceback
-from typing import Callable, List, TypeVar
+from typing import Callable, List, Set, TypeVar
from overrides import overrides
+import id_generator
+
# This module is commonly used by others in here and should avoid
# taking any unnecessary dependencies back on them.
from deferred_operand import DeferredOperand
-import id_generator
logger = logging.getLogger(__name__)
):
real_futures = []
smart_future_by_real_future = {}
- completed_futures = set()
- for _ in futures:
- real_futures.append(_.wrapped_future)
- smart_future_by_real_future[_.wrapped_future] = _
+ completed_futures: Set[fut.Future] = set()
+ for x in futures:
+ assert isinstance(x, SmartFuture)
+ real_futures.append(x.wrapped_future)
+ smart_future_by_real_future[x.wrapped_future] = x
+
while len(completed_futures) != len(real_futures):
newly_completed_futures = concurrent.futures.as_completed(real_futures)
for f in newly_completed_futures:
if log_exceptions and not f.cancelled():
exception = f.exception()
if exception is not None:
- logger.warning(
- f'Future {id(f)} raised an unhandled exception and exited.'
- )
+ logger.warning('Future 0x%x raised an unhandled exception and exited.', id(f))
logger.exception(exception)
raise exception
yield smart_future_by_real_future[f]
if callback is not None:
callback()
- return
def wait_all(
*,
log_exceptions: bool = True,
) -> None:
- real_futures = [x.wrapped_future for x in futures]
+ real_futures = []
+ for x in futures:
+ assert isinstance(x, SmartFuture)
+ real_futures.append(x.wrapped_future)
+
(done, not_done) = concurrent.futures.wait(
real_futures, timeout=None, return_when=concurrent.futures.ALL_COMPLETED
)
if not f.cancelled():
exception = f.exception()
if exception is not None:
- logger.warning(
- f'Future {id(f)} raised an unhandled exception and exited.'
- )
+ logger.warning('Future 0x%x raised an unhandled exception and exited.', id(f))
logger.exception(exception)
raise exception
assert len(done) == len(real_futures)
"""
def __init__(self, wrapped_future: fut.Future) -> None:
+ assert isinstance(wrapped_future, fut.Future)
self.wrapped_future = wrapped_future
self.id = id_generator.get("smart_future_id")
# You shouldn't have to call this; instead, have a look at defining a
# method on DeferredOperand base class.
@overrides
- def _resolve(self, *, timeout=None) -> T:
+ def _resolve(self, timeout=None) -> T:
return self.wrapped_future.result(timeout)