7de8b6be39
git-svn-id: https://svn.code.sf.net/p/flaim/code/trunk@509 0109f412-320b-0410-ab79-c3e0c5ffbbe6
410 lines
8.6 KiB
C++
410 lines
8.6 KiB
C++
//-------------------------------------------------------------------------
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// Desc: Database locking and unlocking.
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// Tabs: 3
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//
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// Copyright (c) 1991,1994-2006 Novell, Inc. All Rights Reserved.
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//
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// This program is free software; you can redistribute it and/or
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// modify it under the terms of version 2 of the GNU General Public
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// License as published by the Free Software Foundation.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, contact Novell, Inc.
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//
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// To contact Novell about this file by physical or electronic mail,
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// you may find current contact information at www.novell.com
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//
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// $Id: lock.cpp 12315 2006-01-19 15:16:37 -0700 (Thu, 19 Jan 2006) dsanders $
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//-------------------------------------------------------------------------
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#include "flaimsys.h"
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/****************************************************************************
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Desc: Obtains a a lock on the database.
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****************************************************************************/
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FLMEXP RCODE FLMAPI FlmDbLock(
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HFDB hDb,
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eLockType lockType,
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FLMINT iPriority,
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FLMUINT uiTimeout)
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{
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RCODE rc = FERR_OK;
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FLMBOOL bIgnore;
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FDB * pDb = (FDB *)hDb;
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if (IsInCSMode( hDb))
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{
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fdbInitCS( pDb);
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CS_CONTEXT * pCSContext = pDb->pCSContext;
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FCL_WIRE Wire( pCSContext, pDb);
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if( !pCSContext->bConnectionGood)
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{
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rc = RC_SET( FERR_BAD_SERVER_CONNECTION);
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goto Transmission_Error;
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}
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if( RC_BAD( rc = Wire.sendOp(
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FCS_OPCLASS_DATABASE, FCS_OP_DATABASE_LOCK)))
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{
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goto Exit;
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}
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if (RC_BAD( rc = Wire.sendNumber( WIRE_VALUE_NUMBER1,
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(FLMUINT)lockType)))
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{
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goto Transmission_Error;
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}
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if (RC_BAD( rc = Wire.sendNumber( WIRE_VALUE_SIGNED_NUMBER,
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0, iPriority)))
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{
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goto Transmission_Error;
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}
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if (RC_BAD( rc = Wire.sendNumber( WIRE_VALUE_FLAGS, uiTimeout)))
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{
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goto Transmission_Error;
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}
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if( RC_BAD( rc = Wire.sendTerminate()))
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{
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goto Transmission_Error;
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}
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// Read the response
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if (RC_BAD( rc = Wire.read()))
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{
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goto Transmission_Error;
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}
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if( RC_BAD( rc = Wire.getRCode()))
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{
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goto Exit;
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}
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goto Exit;
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Transmission_Error:
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pCSContext->bConnectionGood = FALSE;
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goto Exit;
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}
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if (RC_BAD( rc = fdbInit( pDb, FLM_NO_TRANS,
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FDB_TRANS_GOING_OK, 0, &bIgnore)))
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{
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goto Exit;
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}
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// lockType better be exclusive or shared
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if ((lockType != FLM_LOCK_EXCLUSIVE) && (lockType != FLM_LOCK_SHARED))
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{
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rc = RC_SET( FERR_ILLEGAL_OP);
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goto Exit;
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}
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// Nesting of locks is not allowed - this test also keeps this call from
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// being executed inside an update transaction that implicitly acquired
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// the lock.
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if (pDb->uiFlags &
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(FDB_HAS_FILE_LOCK | FDB_FILE_LOCK_SHARED | FDB_FILE_LOCK_IMPLICIT))
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{
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rc = RC_SET( FERR_ILLEGAL_OP);
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goto Exit;
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}
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// Attempt to acquire the lock.
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if (RC_BAD( rc = pDb->pFile->pFileLockObj->lock( pDb->hWaitSem,
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(FLMBOOL)((lockType == FLM_LOCK_EXCLUSIVE)
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? (FLMBOOL)TRUE
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: (FLMBOOL)FALSE),
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uiTimeout, iPriority,
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pDb->pDbStats ? &pDb->pDbStats->LockStats : NULL)))
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{
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goto Exit;
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}
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pDb->uiFlags |= FDB_HAS_FILE_LOCK;
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if (lockType == FLM_LOCK_SHARED)
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{
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pDb->uiFlags |= FDB_FILE_LOCK_SHARED;
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}
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Exit:
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flmExit( FLM_DB_LOCK, pDb, rc);
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return( rc);
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}
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/****************************************************************************
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Desc: Releases a lock on the database
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****************************************************************************/
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FLMEXP RCODE FLMAPI FlmDbUnlock(
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HFDB hDb)
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{
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RCODE rc = FERR_OK;
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FDB * pDb = (FDB *)hDb;
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FLMBOOL bIgnore;
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if (IsInCSMode( hDb))
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{
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fdbInitCS( pDb);
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CS_CONTEXT * pCSContext = pDb->pCSContext;
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FCL_WIRE Wire( pCSContext, pDb);
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if( !pCSContext->bConnectionGood)
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{
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rc = RC_SET( FERR_BAD_SERVER_CONNECTION);
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goto Transmission_Error;
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}
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if( RC_BAD( rc = Wire.sendOp(
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FCS_OPCLASS_DATABASE, FCS_OP_DATABASE_UNLOCK)))
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{
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goto Exit;
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}
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if( RC_BAD( rc = Wire.sendTerminate()))
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{
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goto Transmission_Error;
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}
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// Read the response
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if (RC_BAD( rc = Wire.read()))
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{
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goto Transmission_Error;
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}
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if( RC_BAD( rc = Wire.getRCode()))
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{
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goto Exit;
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}
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goto Exit;
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Transmission_Error:
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pCSContext->bConnectionGood = FALSE;
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goto Exit;
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}
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if (RC_BAD( rc = fdbInit( pDb, FLM_NO_TRANS,
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FDB_TRANS_GOING_OK | FDB_CLOSING_OK, 0, &bIgnore)))
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{
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goto Exit;
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}
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// If we don't have an explicit lock, can't do the unlock. It is
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// also illegal to do the unlock during an update transaction.
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if (!(pDb->uiFlags & FDB_HAS_FILE_LOCK) ||
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(pDb->uiFlags & FDB_FILE_LOCK_IMPLICIT) ||
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(pDb->uiTransType == FLM_UPDATE_TRANS))
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{
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rc = RC_SET( FERR_ILLEGAL_OP);
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goto Exit;
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}
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// Unlock the file.
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if (RC_BAD( rc = pDb->pFile->pFileLockObj->unlock()))
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{
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goto Exit;
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}
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// Unset the flags that indicated the file was explicitly locked.
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pDb->uiFlags &= (~(FDB_HAS_FILE_LOCK | FDB_FILE_LOCK_SHARED));
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Exit:
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if( RC_OK( rc))
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{
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rc = flmCheckDatabaseState( pDb);
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}
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flmExit( FLM_DB_UNLOCK, pDb, rc);
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return( rc);
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}
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/****************************************************************************
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Desc : Returns information about the lock held by the specified database
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handle.
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****************************************************************************/
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FLMEXP RCODE FLMAPI FlmDbGetLockType(
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HFDB hDb,
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eLockType * pLockType,
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FLMBOOL * pbImplicit)
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{
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RCODE rc = FERR_OK;
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FDB * pDb = NULL;
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FLMBOOL bIgnore;
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if( pLockType)
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{
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*pLockType = FLM_LOCK_NONE;
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}
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if( pbImplicit)
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{
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*pbImplicit = FALSE;
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}
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if (IsInCSMode( hDb))
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{
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rc = RC_SET( FERR_NOT_IMPLEMENTED);
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goto Exit;
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}
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pDb = (FDB *)hDb;
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if (RC_BAD( rc = fdbInit( pDb, FLM_NO_TRANS,
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FDB_TRANS_GOING_OK, 0, &bIgnore)))
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{
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goto Exit;
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}
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if( pDb->uiFlags & FDB_HAS_FILE_LOCK)
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{
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if( pLockType)
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{
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if( pDb->uiFlags & FDB_FILE_LOCK_SHARED)
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{
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*pLockType = FLM_LOCK_SHARED;
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}
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else
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{
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*pLockType = FLM_LOCK_EXCLUSIVE;
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}
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}
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if( pbImplicit)
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{
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*pbImplicit = (pDb->uiFlags & FDB_FILE_LOCK_IMPLICIT)
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? TRUE
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: FALSE;
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}
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}
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Exit:
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flmExit( FLM_DB_GET_LOCK_TYPE, pDb, rc);
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return( rc);
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}
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/****************************************************************************
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Desc: This routine locks a database for exclusive access.
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****************************************************************************/
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RCODE dbLock(
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FDB * pDb,
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FLMUINT uiMaxLockWait)
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{
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RCODE rc = FERR_OK;
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FLMBOOL bGotFileLock = FALSE;
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FFILE * pFile = pDb->pFile;
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// There must NOT be a shared lock on the file.
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if (pDb->uiFlags & FDB_FILE_LOCK_SHARED)
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{
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rc = RC_SET( FERR_PERMISSION);
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goto Exit;
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}
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// Must acquire an exclusive file lock first, if it hasn't been
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// acquired.
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if (!(pDb->uiFlags & FDB_HAS_FILE_LOCK))
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{
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if (RC_BAD( rc = pFile->pFileLockObj->lock( pDb->hWaitSem, TRUE,
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uiMaxLockWait, 0, pDb->pDbStats ? &pDb->pDbStats->LockStats : NULL)))
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{
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goto Exit;
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}
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bGotFileLock = TRUE;
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pDb->uiFlags |= (FDB_HAS_FILE_LOCK | FDB_FILE_LOCK_IMPLICIT);
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}
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if (RC_BAD( rc = pFile->pWriteLockObj->lock( pDb->hWaitSem, TRUE,
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uiMaxLockWait, 0, pDb->pDbStats ? &pDb->pDbStats->LockStats : NULL)))
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{
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goto Exit;
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}
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pDb->uiFlags |= FDB_HAS_WRITE_LOCK;
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Exit:
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if (rc == FERR_IO_FILE_LOCK_ERR)
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{
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if (bGotFileLock)
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{
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(void)pFile->pFileLockObj->unlock();
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pDb->uiFlags &= (~(FDB_HAS_FILE_LOCK |
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FDB_FILE_LOCK_IMPLICIT | FDB_HAS_WRITE_LOCK));
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}
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if (pDb->uiTransType != FLM_NO_TRANS)
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{
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// Unlink the DB from the transaction.
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(void)flmUnlinkDbFromTrans( pDb, FALSE);
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}
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}
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else if (RC_BAD( rc))
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{
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if (bGotFileLock)
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{
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(void)pFile->pFileLockObj->unlock();
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pDb->uiFlags &= (~(FDB_HAS_FILE_LOCK |
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FDB_FILE_LOCK_IMPLICIT | FDB_HAS_WRITE_LOCK));
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}
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}
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return( rc);
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}
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/****************************************************************************
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Desc: This routine unlocks a database that was previously locked
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using the dbLock routine.
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****************************************************************************/
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RCODE dbUnlock(
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FDB * pDb)
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{
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RCODE rc = FERR_OK;
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// If we have the write lock, unlock it first.
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flmAssert( pDb->uiFlags & FDB_HAS_WRITE_LOCK);
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pDb->pFile->pWriteLockObj->unlock();
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pDb->uiFlags &= ~FDB_HAS_WRITE_LOCK;
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// Give up the file lock, if it was acquired implicitly.
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if (pDb->uiFlags & FDB_FILE_LOCK_IMPLICIT)
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{
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if (RC_OK( rc = pDb->pFile->pFileLockObj->unlock()))
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{
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pDb->uiFlags &=
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(~(FDB_HAS_FILE_LOCK | FDB_FILE_LOCK_IMPLICIT));
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}
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}
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return( rc);
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}
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