85 lines
2.1 KiB
C++
85 lines
2.1 KiB
C++
/******************************************************************************
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COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2011.
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This file is part of Sortix.
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Sortix is free software: you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation, either version 3 of the License, or (at your option) any later
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version.
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Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along
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with Sortix. If not, see <http://www.gnu.org/licenses/>.
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event.cpp
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Each thread can wait for an event to happen and be signaled when it does.
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******************************************************************************/
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#include <sortix/kernel/platform.h>
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#include "thread.h"
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#include "syscall.h"
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#include "event.h"
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namespace Sortix
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{
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Event::Event()
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{
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waiting = NULL;
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}
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Event::~Event()
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{
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if ( waiting )
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{
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Panic("Thread was waiting on event, but it went out of scope");
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}
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}
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void Event::Register()
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{
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Thread* thread = CurrentThread();
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if ( thread->event )
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{
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Panic("Thread tried to wait on an event, but was already waiting");
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}
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thread->event = this;
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thread->eventnextwaiting = waiting;
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waiting = thread;
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}
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void Event::Signal()
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{
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while ( waiting )
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{
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waiting->event = NULL;
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Syscall::ScheduleResumption(waiting);
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waiting = waiting->eventnextwaiting;
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}
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}
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// TODO: Okay, I realize this is O(N), refactor this to a linked list.
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void Event::Unregister(Thread* thread)
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{
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if ( thread->event != this ) { return; }
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thread->event = NULL;
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if ( waiting == thread ) { waiting = thread->eventnextwaiting; return; }
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for ( Thread* tmp = waiting; tmp; tmp = tmp->eventnextwaiting )
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{
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if ( tmp->eventnextwaiting == thread )
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{
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tmp->eventnextwaiting = thread->eventnextwaiting;
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break;
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}
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}
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thread->eventnextwaiting = NULL;
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}
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}
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