factored out the queue setup of TaskPool._map

setup.cfg

@@ -1,6 +1,6 @@
 [metadata]
 name = asyncio-taskpool
-version = 0.1.2
+version = 0.1.3
 author = Daniil Fajnberg
 author_email = mail@daniil.fajnberg.de
 description = Dynamically manage pools of asyncio tasks

src/asyncio_taskpool/helpers.py

@@ -1,4 +1,5 @@
 from asyncio.coroutines import iscoroutinefunction
+from asyncio.queues import Queue
 from typing import Any, Optional
 
 from .types import T, AnyCallableT, ArgsT, KwArgsT
@@ -22,3 +23,7 @@ def star_function(function: AnyCallableT, arg: Any, arg_stars: int = 0) -> T:
     if arg_stars == 2:
         return function(**arg)
     raise ValueError(f"Invalid argument arg_stars={arg_stars}; must be 0, 1, or 2.")
+
+
+async def join_queue(q: Queue) -> None:
+    await q.join()

src/asyncio_taskpool/pool.py

@@ -10,7 +10,7 @@ from math import inf
 from typing import Any, Awaitable, Dict, Iterable, Iterator, List
 
 from . import exceptions
-from .helpers import execute_optional, star_function
+from .helpers import execute_optional, star_function, join_queue
 from .types import ArgsT, KwArgsT, CoroutineFunc, EndCallbackT, CancelCallbackT
 
 
@@ -498,6 +498,26 @@ class TaskPool(BaseTaskPool):
         await self._queue_consumer(q, func, arg_stars, end_callback=end_callback, cancel_callback=cancel_callback)
         await execute_optional(end_callback, args=(task_id,))
 
+    def _fill_args_queue(self, q: Queue, args_iter: ArgsT, num_tasks: int) -> int:
+        args_iter = iter(args_iter)
+        try:
+            # Here we guarantee that the queue will contain as many arguments as needed for starting the first batch of
+            # tasks, which will be at most `num_tasks` (meaning the queue will be full).
+            for i in range(num_tasks):
+                q.put_nowait(next(args_iter))
+        except StopIteration:
+            # If we get here, this means that the number of elements in the arguments iterator was less than the
+            # specified `num_tasks`. Thus, the number of tasks to start immediately will be the size of the queue.
+            # The `_queue_producer` won't be necessary, since we already put all the elements in the queue.
+            num_tasks = q.qsize()
+        else:
+            # There may be more elements in the arguments iterator, so we need the `_queue_producer`.
+            # It will have exclusive access to the `args_iter` from now on.
+            # If the queue is full already, it will wait until one of the tasks in the first batch ends, before putting
+            # the next item in it.
+            create_task(self._queue_producer(q, args_iter))
+        return num_tasks
+
     async def _map(self, func: CoroutineFunc, args_iter: ArgsT, arg_stars: int = 0, num_tasks: int = 1,
                    end_callback: EndCallbackT = None, cancel_callback: CancelCallbackT = None) -> None:
         """
@@ -533,24 +553,8 @@ class TaskPool(BaseTaskPool):
         if not self.is_open:
             raise exceptions.PoolIsClosed("Cannot start new tasks")
         args_queue = Queue(maxsize=num_tasks)
-        self._before_gathering.append(args_queue.join())
+        self._before_gathering.append(join_queue(args_queue))
-        args_iter = iter(args_iter)
+        num_tasks = self._fill_args_queue(args_queue, args_iter, num_tasks)
-        try:
-            # Here we guarantee that the queue will contain as many arguments as needed for starting the first batch of
-            # tasks, which will be at most `num_tasks` (meaning the queue will be full).
-            for i in range(num_tasks):
-                args_queue.put_nowait(next(args_iter))
-        except StopIteration:
-            # If we get here, this means that the number of elements in the arguments iterator was less than the
-            # specified `num_tasks`. Thus, the number of tasks to start immediately will be the size of the queue.
-            # The `_queue_producer` won't be necessary, since we already put all the elements in the queue.
-            num_tasks = args_queue.qsize()
-        else:
-            # There may be more elements in the arguments iterator, so we need the `_queue_producer`.
-            # It will have exclusive access to the `args_iter` from now on.
-            # If the queue is full already, it will wait until one of the tasks in the first batch ends, before putting
-            # the next item in it.
-            create_task(self._queue_producer(args_queue, args_iter))
         for _ in range(num_tasks):
             # This is where blocking can occur, if the pool is full.
             await self._queue_consumer(args_queue, func,