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/*********************************************************
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* Copyright (C) 1998 VMware, Inc. All rights reserved.
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU Lesser General Public License as published
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* by the Free Software Foundation version 2.1 and no later version.
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the Lesser GNU General Public
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* License for more details.
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*********************************************************/
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* Implements a platform independent wait queue
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#ifndef _SYNC_WAITQ_H_
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#define _SYNC_WAITQ_H_
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#define INCLUDE_ALLOW_USERLEVEL
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#define INCLUDE_ALLOW_VMCORE
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#include "includeCheck.h"
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#include "vm_atomic.h"
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* The semantics of this wait queue primitive are as follows:
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* o Client threads can add themselves to a waitqueue object and
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* receive a pollable handle via a call to SyncWaitQ_Add
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* o When the waitqueue is woken up, each handle that was
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* previously obtained via a call to SyncWaitQ_Add becomes
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* signaled and remains so until it is removed via a call to
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* SyncWaitQ_Remove. Any calls to SyncWaitQ_Add, after the queue
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* has been woken up, will return fresh, unsignaled handles.
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* For more information please refer to comments in the
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* respective syncWaitQ{host}.c files
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* Memory buffer that stores information about an wait queue
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* In the case of named queues, this structure can be allocated
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* on shared memory and shared between multiple processes.
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* This structure, however, cannot be memcpy()-ed
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typedef struct SyncWaitQ {
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* Common members used for both named and unnamed objects
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// Whether the waitqueue has been initialized;
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// Whether queue uses eventfd or pipe
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// Whether there are any waiters on this queue
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Atomic_uint32 waiters;
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// A unique sequence number of the queue
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* Members used in case of named objects
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// Name of the waitqueue object (FIFO path on Linux or Event name on Win32)
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* The following handles are only used only in the case of
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* On Win32 the readHandle is a handle to an event object
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* On Posix the rwHandles are the read and write ends of an anonymous pipe,
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Atomic_uint64 readHandle;
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Atomic_uint64 pipeHandles64;
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Atomic_uint32 pipeHandles[2];
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Atomic_uint32 eventHandle;
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pthread_mutex_t mutex;
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#endif // #ifdef _WIN32
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Bool SyncWaitQ_Init(SyncWaitQ *that, char const *path);
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void SyncWaitQ_Destroy(SyncWaitQ *that);
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PollDevHandle SyncWaitQ_Add(SyncWaitQ *that);
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Bool SyncWaitQ_Remove(SyncWaitQ *that, PollDevHandle fd);
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Bool SyncWaitQ_WakeUp(SyncWaitQ *that);
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#endif // #infdef _SYNC_WAITQ_H_
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lib/include/syncWaitQ.h
