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/**
* @file llpluginsharedmemory.h
*
* @cond
* $LicenseInfo:firstyear=2008&license=viewerlgpl$
* Second Life Viewer Source Code
* Copyright (C) 2010, Linden Research, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License only.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
* $/LicenseInfo$
* @endcond
*/
#ifndef LL_LLPLUGINSHAREDMEMORY_H
#define LL_LLPLUGINSHAREDMEMORY_H
#include "llaprpool.h"
class LLPluginSharedMemoryPlatformImpl;
/**
* @brief LLPluginSharedMemory manages a shared memory segment for use by the LLPlugin API.
*
*/
class LLPluginSharedMemory
{
LOG_CLASS(LLPluginSharedMemory);
public:
LLPluginSharedMemory();
~LLPluginSharedMemory();
// Parent will use create/destroy, child will use attach/detach.
// Message transactions will ensure child attaches after parent creates and detaches before parent destroys.
/**
* Creates a shared memory segment, with a name which is guaranteed to be unique on the host at the current time. Used by parent.
* Message transactions will (? TODO:DOC - should? must?) ensure child attaches after parent creates and detaches before parent destroys.
*
* @param[in] size Shared memory size in TODO:DOC units = bytes?.
*
* @return False for failure, true for success.
*/
bool create(size_t size);
/**
* Destroys a shared memory segment. Used by parent.
* Message transactions will (? TODO:DOC - should? must?) ensure child attaches after parent creates and detaches before parent destroys.
*
* @return True. TODO:DOC - always returns true. Is this the intended behavior?
*/
bool destroy(void);
/**
* Creates and attaches a name to a shared memory segment. TODO:DOC what's the difference between attach() and create()?
*
* @param[in] name Name to attach to memory segment
* @param[in] size Size of memory segment TODO:DOC in bytes?
*
* @return False on failure, true otherwise.
*/
bool attach(const std::string &name, size_t size);
/**
* Detaches shared memory segment.
*
* @return False on failure, true otherwise.
*/
bool detach(void);
/**
* Checks if shared memory is mapped to a non-null address.
*
* @return True if memory address is non-null, false otherwise.
*/
bool isMapped(void) const { return (mMappedAddress != NULL); };
/**
* Get pointer to shared memory.
*
* @return Pointer to shared memory.
*/
void *getMappedAddress(void) const { return mMappedAddress; };
/**
* Get size of shared memory.
*
* @return Size of shared memory in bytes. TODO:DOC are bytes the correct unit?
*/
size_t getSize(void) const { return mSize; };
/**
* Get name of shared memory.
*
* @return Name of shared memory.
*/
std::string getName() const { return mName; };
private:
bool map(void);
bool unmap(void);
bool close(void);
bool unlink(void);
LLAPRPool mPool;
std::string mName;
size_t mSize;
void *mMappedAddress;
bool mNeedsDestroy;
LLPluginSharedMemoryPlatformImpl *mImpl;
static int sSegmentNumber;
static std::string createName();
};
#endif // LL_LLPLUGINSHAREDMEMORY_H
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