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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: NULL; c-basic-offset: 2 -*- */
/*
* The contents of this file are subject to the Mozilla Public
* License Version 1.1 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* The Original Code is the Netscape Portable Runtime (NSPR).
*
* The Initial Developer of the Original Code is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998-2000 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s):
* George Warner, Apple Computer Inc.
* Simon Fraser <sfraser@netscape.com>
*
* Alternatively, the contents of this file may be used under the
* terms of the GNU General Public License Version 2 or later (the
* "GPL"), in which case the provisions of the GPL are applicable
* instead of those above. If you wish to allow use of your
* version of this file only under the terms of the GPL and not to
* allow others to use your version of this file under the MPL,
* indicate your decision by deleting the provisions above and
* replace them with the notice and other provisions required by
* the GPL. If you do not delete the provisions above, a recipient
* may use your version of this file under either the MPL or the
* GPL.
*/
#include "mdcriticalregion.h"
#include <MacErrors.h>
/*
This code is a replacement for MPEnterCriticalRegion/MPLeaveCriticalRegion,
which is broken on Mac OS 10.0.x builds, but fixed in 10.1. This code works
everywhere.
*/
typedef struct MDCriticalRegionData_struct {
MPTaskID mMPTaskID; /* Who's in the critical region? */
UInt32 mDepthCount; /* How deep? */
MPSemaphoreID mMPSemaphoreID; /* ready semaphore */
} MDCriticalRegionData, *MDCriticalRegionDataPtr;
OSStatus
MD_CriticalRegionCreate(MDCriticalRegionID * outCriticalRegionID)
{
MDCriticalRegionDataPtr newCriticalRegionPtr;
MPSemaphoreID mpSemaphoreID;
OSStatus err = noErr;
if (outCriticalRegionID == NULL)
return paramErr;
*outCriticalRegionID = NULL;
newCriticalRegionPtr = (MDCriticalRegionDataPtr)MPAllocateAligned(sizeof(MDCriticalRegionData),
kMPAllocateDefaultAligned, kMPAllocateClearMask);
if (newCriticalRegionPtr == NULL)
return memFullErr;
// Note: this semaphore is pre-fired (ready!)
err = MPCreateBinarySemaphore(&mpSemaphoreID);
if (err == noErr)
{
newCriticalRegionPtr->mMPTaskID = kInvalidID;
newCriticalRegionPtr->mDepthCount = 0;
newCriticalRegionPtr->mMPSemaphoreID = mpSemaphoreID;
*outCriticalRegionID = (MDCriticalRegionID)newCriticalRegionPtr;
}
else
{
MPFree((LogicalAddress)newCriticalRegionPtr);
}
return err;
}
OSStatus
MD_CriticalRegionDelete(MDCriticalRegionID inCriticalRegionID)
{
MDCriticalRegionDataPtr criticalRegion = (MDCriticalRegionDataPtr)inCriticalRegionID;
OSStatus err = noErr;
if (criticalRegion == NULL)
return paramErr;
if ((criticalRegion->mMPTaskID != kInvalidID) && (criticalRegion->mDepthCount > 0))
return kMPInsufficientResourcesErr;
if (criticalRegion->mMPSemaphoreID != kInvalidID)
err = MPDeleteSemaphore(criticalRegion->mMPSemaphoreID);
if (noErr != err) return err;
criticalRegion->mMPSemaphoreID = kInvalidID;
MPFree((LogicalAddress) criticalRegion);
return noErr;
}
OSStatus
MD_CriticalRegionEnter(MDCriticalRegionID inCriticalRegionID, Duration inTimeout)
{
MDCriticalRegionDataPtr criticalRegion = (MDCriticalRegionDataPtr)inCriticalRegionID;
MPTaskID currentTaskID = MPCurrentTaskID();
OSStatus err = noErr;
if (criticalRegion == NULL)
return paramErr;
// if I'm inside the critical region...
if (currentTaskID == criticalRegion->mMPTaskID)
{
// bump my depth
criticalRegion->mDepthCount++;
// and continue
return noErr;
}
// wait for the ready semaphore
err = MPWaitOnSemaphore(criticalRegion->mMPSemaphoreID, inTimeout);
// we didn't get it. return the error
if (noErr != err) return err;
// we got it!
criticalRegion->mMPTaskID = currentTaskID;
criticalRegion->mDepthCount = 1;
return noErr;
}
OSStatus
MD_CriticalRegionExit(MDCriticalRegionID inCriticalRegionID)
{
MDCriticalRegionDataPtr criticalRegion = (MDCriticalRegionDataPtr)inCriticalRegionID;
MPTaskID currentTaskID = MPCurrentTaskID();
OSStatus err = noErr;
// if we don't own the critical region...
if (currentTaskID != criticalRegion->mMPTaskID)
return kMPInsufficientResourcesErr;
// if we aren't at a depth...
if (criticalRegion->mDepthCount == 0)
return kMPInsufficientResourcesErr;
// un-bump my depth
criticalRegion->mDepthCount--;
// if we just bottomed out...
if (criticalRegion->mDepthCount == 0)
{
// release ownership of the structure
criticalRegion->mMPTaskID = kInvalidID;
// and signal the ready semaphore
err = MPSignalSemaphore(criticalRegion->mMPSemaphoreID);
}
return err;
}
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