1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/os/persistentdata/persistentstorage/sql/SRC/Server/SqlSrvDriveSpace.h	Fri Jun 15 03:10:57 2012 +0200
     1.3 @@ -0,0 +1,107 @@
     1.4 +// Copyright (c) 2004-2009 Nokia Corporation and/or its subsidiary(-ies).
     1.5 +// All rights reserved.
     1.6 +// This component and the accompanying materials are made available
     1.7 +// under the terms of "Eclipse Public License v1.0"
     1.8 +// which accompanies this distribution, and is available
     1.9 +// at the URL "http://www.eclipse.org/legal/epl-v10.html".
    1.10 +//
    1.11 +// Initial Contributors:
    1.12 +// Nokia Corporation - initial contribution.
    1.13 +//
    1.14 +// Contributors:
    1.15 +//
    1.16 +// Description:
    1.17 +// Reserving/Accessing/Releasing drive space - CSqlDriveSpace and RSqlDriveSpaceCol classes declarations
    1.18 +// 
    1.19 +//
    1.20 +
    1.21 +#ifndef __SQLSRVDRIVESPACE_H__
    1.22 +#define __SQLSRVDRIVESPACE_H__
    1.23 +
    1.24 +#include <f32file.h>
    1.25 +
    1.26 +//Forward declarations
    1.27 +class RSqlDriveSpaceCol;
    1.28 +class CSqlServer;
    1.29 +
    1.30 +#ifdef _DEBUG
    1.31 +#define SQLDRIVESPACE_INVARIANT() Invariant()
    1.32 +#define SQLDRIVESPACECOL_INVARIANT() Invariant()
    1.33 +#else
    1.34 +#define SQLDRIVESPACE_INVARIANT() void(0)
    1.35 +#define SQLDRIVESPACECOL_INVARIANT() void(0)
    1.36 +#endif
    1.37 +
    1.38 +/**
    1.39 +This class describes an object, which is responsible for handling
    1.40 +"reserve/get access/release" requests for a particular drive.
    1.41 +
    1.42 +Since the drive may be shared between more than one server side session and there is only one RFs instance,
    1.43 +the current solution is that CSqlDriveSpace objects reserve some predefined amount of disk space
    1.44 +at the time of their creation and then the access to the reserved disk space is reference counted.
    1.45 +    There is one obvious disadvantage of this solution: if a bad application "forgets" to release
    1.46 +the access to the reserved disk space, then the reserved (but not released) disk space may be used by the server.
    1.47 +At the moment, when some client will really need the reserved disk space to complete its "delete" transaction, 
    1.48 +it may happen that there is no reserved disk space at all. 
    1.49 +
    1.50 +@see RSqlDriveSpaceCol
    1.51 +@internalComponent
    1.52 +*/
    1.53 +NONSHARABLE_CLASS(CSqlDriveSpace) : public CBase
    1.54 +	{
    1.55 +public:
    1.56 +	static CSqlDriveSpace* NewLC(RFs& aFs, TDriveNumber aDrive);
    1.57 +    virtual ~CSqlDriveSpace();
    1.58 +	inline TDriveNumber Drive() const;
    1.59 +	void GetAccessL();
    1.60 +	void ReleaseAccess();
    1.61 +	void Invariant() const;
    1.62 +
    1.63 +private:
    1.64 +	CSqlDriveSpace(RFs& aFs, TDriveNumber aDrive);
    1.65 +    void ConstructL();
    1.66 +
    1.67 +private:
    1.68 +	RFs& 			iFs;               	//File session reference
    1.69 +	TDriveNumber 	iDrive;    			//Drive number
    1.70 +	TInt 			iGetAccessRefCnt;	//"Get access" requests count
    1.71 +
    1.72 +	};
    1.73 +
    1.74 +/**
    1.75 +@return The drive number, where the CSqlDriveSpace object handles the reservation requests
    1.76 +*/
    1.77 +inline TDriveNumber CSqlDriveSpace::Drive() const
    1.78 +    {
    1.79 +    return iDrive;
    1.80 +    }
    1.81 +
    1.82 +/**
    1.83 +This class describes a collection of CSqlDriveSpace objects. Each CSqlDriveSpace object in the
    1.84 +collection is responsible for handling "reserve/get access/release" requests for a particular
    1.85 +drive.
    1.86 +
    1.87 +Only one RSqlDriveSpaceCol instance should be created (resp. destroyed) by the CSqlServer object.
    1.88 +
    1.89 +@see CSqlServer
    1.90 +@see CSqlDriveSpace
    1.91 +
    1.92 +@internalComponent
    1.93 +*/
    1.94 +NONSHARABLE_CLASS(RSqlDriveSpaceCol)
    1.95 +	{
    1.96 +public:
    1.97 +	RSqlDriveSpaceCol();
    1.98 +	void Create(RFs& aFs);
    1.99 +	void ResetAndDestroy();
   1.100 +    CSqlDriveSpace* Find(TDriveNumber aDrive);
   1.101 +    CSqlDriveSpace* AddL(TDriveNumber aDrive);
   1.102 +	void Invariant() const;
   1.103 +
   1.104 +private:
   1.105 +	RFs*				        	iFs;            //File session reference
   1.106 +	RPointerArray<CSqlDriveSpace>	iDriveSpaceCol; //Collection of CSqlDriveSpace objects: one per drive
   1.107 +
   1.108 +	};
   1.109 +
   1.110 +#endif//__SQLSRVDRIVESPACE_H__