65 lines
2.0 KiB
C++
65 lines
2.0 KiB
C++
// Filename: mutexLinuxImpl.cxx
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// Created by: drose (28Mar06)
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//
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////////////////////////////////////////////////////////////////////
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//
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// PANDA 3D SOFTWARE
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// Copyright (c) 2001 - 2004, Disney Enterprises, Inc. All rights reserved
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//
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// All use of this software is subject to the terms of the Panda 3d
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// Software license. You should have received a copy of this license
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// along with this source code; you will also find a current copy of
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// the license at http://etc.cmu.edu/panda3d/docs/license/ .
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//
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// To contact the maintainers of this program write to
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// panda3d-general@lists.sourceforge.net .
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//
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////////////////////////////////////////////////////////////////////
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#include "selectThreadImpl.h"
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#ifdef HAVE_LINUX_NATIVE_THREADS
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#include "mutexLinuxImpl.h"
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#include "atomicAdjust.h"
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#include <linux/futex.h>
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#include <sys/time.h>
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#include <sys/syscall.h>
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////////////////////////////////////////////////////////////////////
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// Function: MutexLinuxImpl::lock
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// Access: Public
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// Description:
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////////////////////////////////////////////////////////////////////
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void MutexLinuxImpl::
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lock() {
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PN_int32 c;
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c = AtomicAdjust::compare_and_exchange
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(_mode, M_unlocked, M_locked_no_waiters);
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while (c != M_unlocked) {
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if (c == M_locked_with_waiters ||
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AtomicAdjust::compare_and_exchange(_mode, M_locked_no_waiters,
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M_locked_with_waiters) != M_unlocked) {
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syscall(SYS_futex, &_mode, FUTEX_WAIT, M_locked_with_waiters, (void *)NULL);
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}
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c = AtomicAdjust::compare_and_exchange
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(_mode, M_unlocked, M_locked_with_waiters);
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}
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}
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////////////////////////////////////////////////////////////////////
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// Function: MutexLinuxImpl::release
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// Access: Public
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// Description:
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////////////////////////////////////////////////////////////////////
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void MutexLinuxImpl::
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release() {
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if (AtomicAdjust::dec(_mode)) {
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_mode = M_unlocked;
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syscall(SYS_futex, &_mode, FUTEX_WAKE, 1);
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}
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}
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#endif // HAVE_LINUX_NATIVE_THREADS
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