/* $Id: semspingpong.cpp 99758 2023-05-11 21:37:59Z vboxsync $ */
/** @file
 * IPRT - Thread Ping-Pong Construct.
 */

/*
 * Copyright (C) 2006-2023 Oracle and/or its affiliates.
 *
 * This file is part of VirtualBox base platform packages, as
 * available from https://www.virtualbox.org.
 *
 * This program 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, in version 3 of the
 * License.
 *
 * This program 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 this program; if not, see <https://www.gnu.org/licenses>.
 *
 * The contents of this file may alternatively be used under the terms
 * of the Common Development and Distribution License Version 1.0
 * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
 * in the VirtualBox distribution, in which case the provisions of the
 * CDDL are applicable instead of those of the GPL.
 *
 * You may elect to license modified versions of this file under the
 * terms and conditions of either the GPL or the CDDL or both.
 *
 * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
 */


/*********************************************************************************************************************************
*   Header Files                                                                                                                 *
*********************************************************************************************************************************/
#include <iprt/semaphore.h>
#include "internal/iprt.h"

#include <iprt/thread.h>
#include <iprt/asm.h>
#include <iprt/assert.h>
#include <iprt/err.h>


/*********************************************************************************************************************************
*   Defined Constants And Macros                                                                                                 *
*********************************************************************************************************************************/
/**
 * Validation macro returns if invalid parameter.
 *
 * Expects a enmSpeaker variable to be handy and will set it to the current
 * enmSpeaker value.
 */
#define RTSEMPP_VALIDATE_RETURN(pPP) \
    do { \
        AssertPtrReturn(pPP, VERR_INVALID_PARAMETER); \
        AssertCompileSize(pPP->enmSpeaker, 4); \
        enmSpeaker = (RTPINGPONGSPEAKER)ASMAtomicUoReadU32((volatile uint32_t *)&pPP->enmSpeaker); \
        AssertMsgReturn(    enmSpeaker == RTPINGPONGSPEAKER_PING \
                        ||  enmSpeaker == RTPINGPONGSPEAKER_PONG \
                        ||  enmSpeaker == RTPINGPONGSPEAKER_PONG_SIGNALED \
                        ||  enmSpeaker == RTPINGPONGSPEAKER_PING_SIGNALED, \
                        ("enmSpeaker=%d\n", enmSpeaker), \
                        VERR_INVALID_PARAMETER); \
    } while (0)


RTDECL(int) RTSemPingPongInit(PRTPINGPONG pPP)
{
    /*
     * Init the structure.
     */
    pPP->enmSpeaker = RTPINGPONGSPEAKER_PING;

    int rc = RTSemEventCreate(&pPP->Ping);
    if (RT_SUCCESS(rc))
    {
        rc = RTSemEventCreate(&pPP->Pong);
        if (RT_SUCCESS(rc))
            return VINF_SUCCESS;
        RTSemEventDestroy(pPP->Ping);
    }

    return rc;
}
RT_EXPORT_SYMBOL(RTSemPingPongInit);


RTDECL(int) RTSemPingPongDelete(PRTPINGPONG pPP)
{
    /*
     * Validate input
     */
    if (!pPP)
        return VINF_SUCCESS;
    RTPINGPONGSPEAKER enmSpeaker;
    RTSEMPP_VALIDATE_RETURN(pPP);

    /*
     * Invalidate the ping pong handle and destroy the event semaphores.
     */
    ASMAtomicWriteSize(&pPP->enmSpeaker, RTPINGPONGSPEAKER_UNINITIALIZE);
    int rc = RTSemEventDestroy(pPP->Ping);
    int rc2 = RTSemEventDestroy(pPP->Pong);
    AssertRC(rc);
    AssertRC(rc2);

    return VINF_SUCCESS;
}
RT_EXPORT_SYMBOL(RTSemPingPongDelete);


RTDECL(int) RTSemPing(PRTPINGPONG pPP)
{
    /*
     * Validate input
     */
    RTPINGPONGSPEAKER enmSpeaker;
    RTSEMPP_VALIDATE_RETURN(pPP);
    AssertMsgReturn(enmSpeaker == RTPINGPONGSPEAKER_PING,("Speaking out of turn! enmSpeaker=%d\n", enmSpeaker),
                    VERR_SEM_OUT_OF_TURN);

    /*
     * Signal the other thread.
     */
    ASMAtomicWriteSize(&pPP->enmSpeaker, RTPINGPONGSPEAKER_PONG_SIGNALED);
    int rc = RTSemEventSignal(pPP->Pong);
    if (RT_SUCCESS(rc))
        return rc;

    /* restore the state. */
    AssertMsgFailed(("Failed to signal pong sem %x. rc=%Rrc\n",  pPP->Pong,  rc));
    ASMAtomicWriteSize(&pPP->enmSpeaker, RTPINGPONGSPEAKER_PING);
    return rc;
}
RT_EXPORT_SYMBOL(RTSemPing);


RTDECL(int) RTSemPong(PRTPINGPONG pPP)
{
    /*
     * Validate input
     */
    RTPINGPONGSPEAKER enmSpeaker;
    RTSEMPP_VALIDATE_RETURN(pPP);
    AssertMsgReturn(enmSpeaker == RTPINGPONGSPEAKER_PONG,("Speaking out of turn! enmSpeaker=%d\n", enmSpeaker),
                    VERR_SEM_OUT_OF_TURN);

    /*
     * Signal the other thread.
     */
    ASMAtomicWriteSize(&pPP->enmSpeaker, RTPINGPONGSPEAKER_PING_SIGNALED);
    int rc = RTSemEventSignal(pPP->Ping);
    if (RT_SUCCESS(rc))
        return rc;

    /* restore the state. */
    AssertMsgFailed(("Failed to signal ping sem %x. rc=%Rrc\n",  pPP->Ping,  rc));
    ASMAtomicWriteSize(&pPP->enmSpeaker, RTPINGPONGSPEAKER_PONG);
    return rc;
}
RT_EXPORT_SYMBOL(RTSemPong);


RTDECL(int) RTSemPingWait(PRTPINGPONG pPP, RTMSINTERVAL cMillies)
{
    /*
     * Validate input
     */
    RTPINGPONGSPEAKER enmSpeaker;
    RTSEMPP_VALIDATE_RETURN(pPP);
    AssertMsgReturn(    enmSpeaker == RTPINGPONGSPEAKER_PONG
                    ||  enmSpeaker == RTPINGPONGSPEAKER_PONG_SIGNALED
                    ||  enmSpeaker == RTPINGPONGSPEAKER_PING_SIGNALED,
                    ("Speaking out of turn! enmSpeaker=%d\n", enmSpeaker),
                    VERR_SEM_OUT_OF_TURN);

    /*
     * Wait.
     */
    int rc = RTSemEventWait(pPP->Ping, cMillies);
    if (RT_SUCCESS(rc))
        ASMAtomicWriteSize(&pPP->enmSpeaker, RTPINGPONGSPEAKER_PING);
    Assert(rc != VERR_INTERRUPTED);
    return rc;
}
RT_EXPORT_SYMBOL(RTSemPingWait);


RTDECL(int) RTSemPongWait(PRTPINGPONG pPP, RTMSINTERVAL cMillies)
{
    /*
     * Validate input
     */
    RTPINGPONGSPEAKER enmSpeaker;
    RTSEMPP_VALIDATE_RETURN(pPP);
    AssertMsgReturn(    enmSpeaker == RTPINGPONGSPEAKER_PING
                    ||  enmSpeaker == RTPINGPONGSPEAKER_PING_SIGNALED
                    ||  enmSpeaker == RTPINGPONGSPEAKER_PONG_SIGNALED,
                    ("Speaking out of turn! enmSpeaker=%d\n", enmSpeaker),
                    VERR_SEM_OUT_OF_TURN);

    /*
     * Wait.
     */
    int rc = RTSemEventWait(pPP->Pong, cMillies);
    if (RT_SUCCESS(rc))
        ASMAtomicWriteSize(&pPP->enmSpeaker, RTPINGPONGSPEAKER_PONG);
    Assert(rc != VERR_INTERRUPTED);
    return rc;
}
RT_EXPORT_SYMBOL(RTSemPongWait);