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-rw-r--r--src/VBox/Runtime/common/misc/semspingpong.cpp251
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diff --git a/src/VBox/Runtime/common/misc/semspingpong.cpp b/src/VBox/Runtime/common/misc/semspingpong.cpp
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+/* $Id: semspingpong.cpp $ */
+/** @file
+ * IPRT - Thread Ping-Pong Construct.
+ */
+
+/*
+ * Copyright (C) 2006-2020 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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