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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