qa_defer.cpp

00001 //////////////////////////////////////////////////////////////////////////////
00002 // Product: QF/C++
00003 // Last Updated for Version: 4.0.00
00004 // Date of the Last Update:  Apr 07, 2008
00005 //
00006 //                    Q u a n t u m     L e a P s
00007 //                    ---------------------------
00008 //                    innovating embedded systems
00009 //
00010 // Copyright (C) 2002-2008 Quantum Leaps, LLC. All rights reserved.
00011 //
00012 // This software may be distributed and modified under the terms of the GNU
00013 // General Public License version 2 (GPL) as published by the Free Software
00014 // Foundation and appearing in the file GPL.TXT included in the packaging of
00015 // this file. Please note that GPL Section 2[b] requires that all works based
00016 // on this software must also be made publicly available under the terms of
00017 // the GPL ("Copyleft").
00018 //
00019 // Alternatively, this software may be distributed and modified under the
00020 // terms of Quantum Leaps commercial licenses, which expressly supersede
00021 // the GPL and are specifically designed for licensees interested in
00022 // retaining the proprietary status of their code.
00023 //
00024 // Contact information:
00025 // Quantum Leaps Web site:  http://www.quantum-leaps.com
00026 // e-mail:                  info@quantum-leaps.com
00027 //////////////////////////////////////////////////////////////////////////////
00028 #include "qf_pkg.h"
00029 #include "qassert.h"
00030 
00031 Q_DEFINE_THIS_MODULE(qa_defer)
00032 
00033 /// \file
00034 /// \ingroup qf
00035 /// \brief QActive::defer() and QActive::recall() implementation.
00036 ///
00037 
00038 //............................................................................
00039 void QActive::defer(QEQueue *eq, QEvent const *e) {
00040     eq->postFIFO(e);
00041 }
00042 //............................................................................
00043 QEvent const *QActive::recall(QEQueue *eq) {
00044     QEvent const *e = eq->get();    // try to get an event from deferred queue
00045     if (e != (QEvent *)0) {                                // event available?
00046 
00047         postLIFO(e);      // post it to the front of the Active Object's queue
00048 
00049         QF_INT_LOCK_KEY_
00050         QF_INT_LOCK_();
00051 
00052         if (e->dynamic_ != (uint8_t)0) {             // is it a dynamic event?
00053 
00054             // after posting to the AO's queue the event must be referenced
00055             // at least twice: once in the deferred event queue (eq->get()
00056             // did NOT decrement the reference counter) and once in the
00057             // AO's event queue.
00058             Q_ASSERT((e->dynamic_ & 0x3F) > 1);
00059 
00060             // we need to decrement the reference counter once, to account
00061             // for removing the event from the deferred event queue.
00062             //
00063             //lint -e1773                           Attempt to cast away const
00064             --((QEvent *)e)->dynamic_;      // decrement the reference counter
00065                    // NOTE: cast the 'const' away, which is legitimate because
00066                    // it's a dynamic event
00067         }
00068 
00069         QF_INT_UNLOCK_();
00070 
00071     }
00072     return e;  // pass the recalled event to the caller (NULL if not recalled)
00073 }