shflhandle.cpp revision df277f214bcaae98f80456ec998330eaa7460eca
/** @file
*
* Shared Folders:
* Handles helper functions.
*/
/*
* Copyright (C) 2006-2007 Sun Microsystems, Inc.
*
* 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.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 USA or visit http://www.sun.com if you need
* additional information or have any questions.
*/
#include "shflhandle.h"
#include <iprt/alloc.h>
#include <iprt/assert.h>
#include <iprt/critsect.h>
/*
* Very basic and primitive handle management. Should be sufficient for our needs.
* Handle allocation can be rather slow, but at least lookup is fast.
*
*/
typedef struct
{
uint32_t uFlags;
uintptr_t pvUserData;
} SHFLINTHANDLE, *PSHFLINTHANDLE;
static SHFLINTHANDLE *pHandles = NULL;
static int32_t lastHandleIndex = 0;
static RTCRITSECT lock;
int vbsfInitHandleTable()
{
pHandles = (SHFLINTHANDLE *)RTMemAllocZ (sizeof (SHFLINTHANDLE) * SHFLHANDLE_MAX);
if (pHandles == NULL)
{
AssertFailed();
return VERR_NO_MEMORY;
}
/* Never return handle 0 */
pHandles[0].uFlags = SHFL_HF_TYPE_DONTUSE;
lastHandleIndex = 1;
return RTCritSectInit(&lock);
}
int vbsfFreeHandleTable()
{
if (pHandles)
RTMemFree(pHandles);
pHandles = NULL;
if (RTCritSectIsInitialized(&lock))
RTCritSectDelete(&lock);
return VINF_SUCCESS;
}
SHFLHANDLE vbsfAllocHandle(uint32_t uType, uintptr_t pvUserData)
{
SHFLHANDLE handle;
Assert((uType & SHFL_HF_TYPE_MASK) != 0 && pvUserData);
RTCritSectEnter(&lock);
/* Find next free handle */
if(lastHandleIndex >= SHFLHANDLE_MAX-1)
{
lastHandleIndex = 1;
}
/* Nice linear search */
for(handle=lastHandleIndex;handle<SHFLHANDLE_MAX;handle++)
{
if(pHandles[handle].pvUserData == 0)
{
lastHandleIndex = handle;
break;
}
}
if(handle == SHFLHANDLE_MAX)
{
/* Try once more from the start */
for(handle=1;handle<SHFLHANDLE_MAX;handle++)
{
if(pHandles[handle].pvUserData == 0)
{
lastHandleIndex = handle;
break;
}
}
if(handle == SHFLHANDLE_MAX)
{ /* Out of handles */
RTCritSectLeave(&lock);
AssertFailed();
return SHFL_HANDLE_NIL;
}
}
pHandles[handle].uFlags = (uType & SHFL_HF_TYPE_MASK) | SHFL_HF_VALID;
pHandles[handle].pvUserData = pvUserData;
lastHandleIndex++;
RTCritSectLeave(&lock);
return handle;
}
int vbsfFreeHandle(SHFLHANDLE handle)
{
if (handle < SHFLHANDLE_MAX && (pHandles[handle].uFlags & SHFL_HF_VALID))
{
pHandles[handle].uFlags = 0;
pHandles[handle].pvUserData = 0;
return VINF_SUCCESS;
}
return VERR_INVALID_HANDLE;
}
uintptr_t vbsfQueryHandle(SHFLHANDLE handle, uint32_t uType)
{
if (handle < SHFLHANDLE_MAX && (pHandles[handle].uFlags & SHFL_HF_VALID))
{
Assert((uType & SHFL_HF_TYPE_MASK) != 0);
if (pHandles[handle].uFlags & uType)
return pHandles[handle].pvUserData;
}
return 0;
}
SHFLHANDLE vbsfAllocDirHandle (void)
{
SHFLFILEHANDLE *pHandle = (SHFLFILEHANDLE *)RTMemAllocZ (sizeof (SHFLFILEHANDLE));
if (pHandle)
{
pHandle->Header.u32Flags = SHFL_HF_TYPE_DIR;
return vbsfAllocHandle(pHandle->Header.u32Flags, (uintptr_t)pHandle);
}
return SHFL_HANDLE_NIL;
}
SHFLHANDLE vbsfAllocFileHandle (void)
{
SHFLFILEHANDLE *pHandle = (SHFLFILEHANDLE *)RTMemAllocZ (sizeof (SHFLFILEHANDLE));
if (pHandle)
{
pHandle->Header.u32Flags = SHFL_HF_TYPE_FILE;
return vbsfAllocHandle(pHandle->Header.u32Flags, (uintptr_t)pHandle);
}
return SHFL_HANDLE_NIL;
}
void vbsfFreeFileHandle (SHFLHANDLE hHandle)
{
SHFLFILEHANDLE *pHandle = (SHFLFILEHANDLE *)vbsfQueryHandle(hHandle, SHFL_HF_TYPE_DIR|SHFL_HF_TYPE_FILE);
if (pHandle)
{
vbsfFreeHandle(hHandle);
RTMemFree (pHandle);
}
else
AssertFailed();
return;
}