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/* $Id: semspingpong.cpp $ */
/** @file
* IPRT - Thread Ping-Pong Construct.
*/
/*
* Copyright (C) 2006-2019 Oracle Corporation
*
* This file is part of VirtualBox Open Source Edition (OSE), as
* available from http://www.virtualbox.org. This file is free software;
* you can redistribute it and/or modify it under the terms of the GNU
* General Public License (GPL) as published by the Free Software
* Foundation, in version 2 as it comes in the "COPYING" file of the
* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
* VirtualBox OSE 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.
*/
/*********************************************************************************************************************************
* 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)
/**
* Init a Ping-Pong construct.
*
* @returns iprt status code.
* @param pPP Pointer to the ping-pong structure which needs initialization.
*/
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);
/**
* Destroys a Ping-Pong construct.
*
* @returns iprt status code.
* @param pPP Pointer to the ping-pong structure which is to be destroyed.
* (I.e. put into uninitialized state.)
*/
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);
/**
* Signals the pong thread in a ping-pong construct. (I.e. sends ping.)
* This is called by the ping thread.
*
* @returns iprt status code.
* @param pPP Pointer to the ping-pong structure to ping.
*/
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);
/**
* Signals the ping thread in a ping-pong construct. (I.e. sends pong.)
* This is called by the pong thread.
*
* @returns iprt status code.
* @param pPP Pointer to the ping-pong structure to pong.
*/
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);
/**
* Wait function for the ping thread.
*
* @returns iprt status code.
* Will not return VERR_INTERRUPTED.
* @param pPP Pointer to the ping-pong structure to wait on.
* @param cMillies Number of milliseconds to wait.
*/
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);
/**
* Wait function for the pong thread.
*
* @returns iprt status code.
* Will not return VERR_INTERRUPTED.
* @param pPP Pointer to the ping-pong structure to wait on.
* @param cMillies Number of milliseconds to wait.
*/
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);
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