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sortix--sortix/sortix/event.cpp
Jonas 'Sortie' Termansen 9bcfdad174 Added protection against running terminated threads.
A bool is set when a thread is terminated, which may help detect it.

A cached version of the thread's pid is also kept around.

And lastly, the thread is unsubscribed from events upon destruction.
2012-02-10 13:27:11 +01:00

84 lines
2 KiB
C++

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