Augustin Cavalier
f66d2b46a8
Based on hamishm's original patch from 2015, but heavily modified,
refactored, and reworked.
From the original commit message:
> When an object is deleted, a B_EVENT_INVALID event is delivered,
> and the object is unregistered from the queue.
>
> The special event flag B_EVENT_ONE_SHOT can be passed in when adding
> an object so that the object is automatically unregistered when an
> event is delivered.
Modifications to the original change include:
* Removed the public interface (syscalls remain private for the moment)
* Event list queueing/dequeueing almost entirely rewritten, including:
- Clear events field when dequeueing.
- Have B_EVENT_QUEUED actually indicate whether the event has been
appended to the linked list (or not), based around lock state.
The previous logic was prone to races and double-insertions.
- "Modify" is now just "Deselect + Select" performed at once;
previously it could cause use-after-frees.
- Unlock for deselect only once at the end of dequeue.
- Handle INVALID events still in the queue upon destruction,
fixing memory leaks.
* Deduplified code with wait_for_objects.
* Use of C++ virtual dispatch instead of C-style enum + function calls,
and BReferenceable plus destructors for teardown.
* Removed select/modify/delete flags. Select/Modify are now the same
operation on the syscall interface, and "Delete" is done when 0
is passed for "events". Additionally, the events selected can be fetched
by passing -1 for "events".
* Implemented level-triggered mode.
* Use of BStackOrHeapArray and other convenience routines in syscalls.
Change-Id: I1d2f094fd981c95215a59adbc087523c7bbbe40b
Reviewed-on: https://review.haiku-os.org/c/haiku/+/6745
Tested-by: Commit checker robot <[email protected]>
Reviewed-by: Jérôme Duval <[email protected]>
30 lines
604 B
C
30 lines
604 B
C
/*
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* Copyright 2015, Hamish Morrison, [email protected].
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* All rights reserved. Distributed under the terms of the MIT License.
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*/
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#ifndef _KERNEL_EVENT_QUEUE_H
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#define _KERNEL_EVENT_QUEUE_H
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#include <OS.h>
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#include <event_queue_defs.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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extern int _user_event_queue_create(int openFlags);
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extern status_t _user_event_queue_select(int queue, event_wait_info* userInfos,
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int numInfos);
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extern ssize_t _user_event_queue_wait(int queue, event_wait_info* infos,
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int numInfos, uint32 flags, bigtime_t timeout);
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#ifdef __cplusplus
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}
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#endif
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#endif
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