2b72262b4f
I hereby relicense all my work on Sortix under the ISC license as below. All Sortix contributions by other people are already under this license, are not substantial enough to be copyrightable, or have been removed. All imported code from other projects is compatible with this license. All GPL licensed code from other projects had previously been removed. Copyright 2011-2016 Jonas 'Sortie' Termansen and contributors. Permission to use, copy, modify, and distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies. THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
107 lines
2.7 KiB
C++
107 lines
2.7 KiB
C++
/*
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* Copyright (c) 2012, 2013, 2015 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* textbuffer.cpp
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* Provides a indexable text buffer for used by text mode terminals.
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*/
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#include <assert.h>
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#include <errno.h>
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#include <sortix/kernel/kernel.h>
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#include <sortix/kernel/kthread.h>
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#include <sortix/kernel/refcount.h>
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#include <sortix/kernel/textbuffer.h>
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namespace Sortix {
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TextBufferHandle::TextBufferHandle(TextBuffer* textbuf)
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{
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this->textbuf = textbuf;
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this->numused = 0;
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this->mutex = KTHREAD_MUTEX_INITIALIZER;
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this->unusedcond = KTHREAD_COND_INITIALIZER;
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}
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TextBufferHandle::~TextBufferHandle()
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{
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delete textbuf;
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}
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TextBuffer* TextBufferHandle::Acquire()
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{
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ScopedLock lock(&mutex);
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if ( !textbuf )
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return errno = EINIT, (TextBuffer*) NULL;
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numused++;
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return textbuf;
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}
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void TextBufferHandle::Release(TextBuffer* textbuf)
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{
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assert(textbuf);
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ScopedLock lock(&mutex);
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assert(numused);
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numused--;
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if ( numused == 0 )
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kthread_cond_signal(&unusedcond);
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}
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bool TextBufferHandle::EmergencyIsImpaired()
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{
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if ( !kthread_mutex_trylock(&mutex) )
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return true;
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kthread_mutex_unlock(&mutex);
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return false;
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}
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bool TextBufferHandle::EmergencyRecoup()
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{
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if ( !EmergencyIsImpaired() )
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return true;
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mutex = KTHREAD_MUTEX_INITIALIZER;
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return true;
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}
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void TextBufferHandle::EmergencyReset()
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{
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}
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TextBuffer* TextBufferHandle::EmergencyAcquire()
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{
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// This is during a kernel emergency where preemption has been disabled and
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// this is the only thread running.
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return textbuf;
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}
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void TextBufferHandle::EmergencyRelease(TextBuffer* textbuf)
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{
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// This is during a kernel emergency where preemption has been disabled and
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// this is the only thread running. We don't maintain the reference count
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// during this state, so this is a no-operation.
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(void) textbuf;
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}
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void TextBufferHandle::Replace(TextBuffer* newtextbuf)
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{
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ScopedLock lock(&mutex);
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while ( 0 < numused )
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kthread_cond_wait(&unusedcond, &mutex);
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delete textbuf;
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textbuf = newtextbuf;
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}
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} // namespace Sortix
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