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The host’s running event loop, shared with jobs that run on another thread of execution. A backend whose pool runs its jobs as green threads of the host’s one OS thread cannot give a job a loop of its own: asyncio runs one loop per OS thread at a time, and the host already runs its loop there. SharedLoop hands each job’s coroutine to the host’s loop instead, and the job waits for its result.

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SharedLoop

tai42_kit.backend.shared_loop.SharedLoop
A loop that already runs on another thread of execution, to which a job hands its coroutine and then waits. The loop is the host’s: this object neither runs, stops nor closes it, and the kit’s resources bound to it are the host’s, released by its stop. A job’s coroutine runs as a task of that loop, in the context the job handed it in, and the job’s thread waits for the task’s outcome. Where every job is a green thread of the loop’s own OS thread, that wait yields to the other green threads, so the jobs’ coroutines interleave on the loop with the host’s own work. Jobs run on it while the host runs it; a job handed once it has closed, or once close has run, raises at once.

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Members

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run

tai42_kit.backend.shared_loop.SharedLoop.run
Run coroutine to completion on the host’s loop and return its result, or raise its exception. The job raises what the coroutine’s task ends with, CancelledError when the task was cancelled (as the host’s run ends every task left on its loop). An exception raised into the job’s wait (its pool’s time limit, a stop of the job) cancels the coroutine’s task on the loop and waits on until that task has ended, its cleanup included: the job holds what it holds until its coroutine has ended, and then raises that exception. Each further exception raised into the wait is forwarded as another cancel the same way, and the job ends with the last, each earlier one as its context. An error the coroutine ends with meanwhile is logged at ERROR with its traceback, since the job raises the wait’s exception. A coroutine that swallows the cancel is waited for until it returns, and the job still ends with the wait’s exception. Parameters

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close

tai42_kit.backend.shared_loop.SharedLoop.close
Let the host’s loop go: every later job is refused; the loop and its kit resources stay the host’s.