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1 // Copyright (c) 2004-2009 Nokia Corporation and/or its subsidiary(-ies). |
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2 // All rights reserved. |
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3 // This component and the accompanying materials are made available |
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4 // under the terms of "Eclipse Public License v1.0" |
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5 // which accompanies this distribution, and is available |
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6 // at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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7 // |
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8 // Initial Contributors: |
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9 // Nokia Corporation - initial contribution. |
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10 // |
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11 // Contributors: |
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12 // |
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13 // Description: |
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14 // Reserving/Accessing/Releasing drive space - CSqlDriveSpace and RSqlDriveSpaceCol classes declarations |
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15 // |
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16 // |
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17 |
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18 #ifndef __SQLSRVDRIVESPACE_H__ |
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19 #define __SQLSRVDRIVESPACE_H__ |
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20 |
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21 #include <f32file.h> |
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22 |
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23 //Forward declarations |
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24 class RSqlDriveSpaceCol; |
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25 class CSqlServer; |
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26 |
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27 #ifdef _DEBUG |
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28 #define SQLDRIVESPACE_INVARIANT() Invariant() |
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29 #define SQLDRIVESPACECOL_INVARIANT() Invariant() |
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30 #else |
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31 #define SQLDRIVESPACE_INVARIANT() void(0) |
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32 #define SQLDRIVESPACECOL_INVARIANT() void(0) |
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33 #endif |
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34 |
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35 /** |
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36 This class describes an object, which is responsible for handling |
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37 "reserve/get access/release" requests for a particular drive. |
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38 |
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39 Since the drive may be shared between more than one server side session and there is only one RFs instance, |
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40 the current solution is that CSqlDriveSpace objects reserve some predefined amount of disk space |
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41 at the time of their creation and then the access to the reserved disk space is reference counted. |
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42 There is one obvious disadvantage of this solution: if a bad application "forgets" to release |
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43 the access to the reserved disk space, then the reserved (but not released) disk space may be used by the server. |
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44 At the moment, when some client will really need the reserved disk space to complete its "delete" transaction, |
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45 it may happen that there is no reserved disk space at all. |
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46 |
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47 @see RSqlDriveSpaceCol |
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48 @internalComponent |
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49 */ |
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50 NONSHARABLE_CLASS(CSqlDriveSpace) : public CBase |
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51 { |
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52 public: |
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53 static CSqlDriveSpace* NewLC(RFs& aFs, TDriveNumber aDrive); |
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54 virtual ~CSqlDriveSpace(); |
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55 inline TDriveNumber Drive() const; |
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56 void GetAccessL(); |
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57 void ReleaseAccess(); |
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58 void Invariant() const; |
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59 |
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60 private: |
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61 CSqlDriveSpace(RFs& aFs, TDriveNumber aDrive); |
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62 void ConstructL(); |
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63 |
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64 private: |
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65 RFs& iFs; //File session reference |
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66 TDriveNumber iDrive; //Drive number |
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67 TInt iGetAccessRefCnt; //"Get access" requests count |
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68 |
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69 }; |
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70 |
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71 /** |
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72 @return The drive number, where the CSqlDriveSpace object handles the reservation requests |
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73 */ |
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74 inline TDriveNumber CSqlDriveSpace::Drive() const |
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75 { |
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76 return iDrive; |
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77 } |
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78 |
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79 /** |
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80 This class describes a collection of CSqlDriveSpace objects. Each CSqlDriveSpace object in the |
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81 collection is responsible for handling "reserve/get access/release" requests for a particular |
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82 drive. |
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83 |
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84 Only one RSqlDriveSpaceCol instance should be created (resp. destroyed) by the CSqlServer object. |
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85 |
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86 @see CSqlServer |
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87 @see CSqlDriveSpace |
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88 |
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89 @internalComponent |
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90 */ |
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91 NONSHARABLE_CLASS(RSqlDriveSpaceCol) |
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92 { |
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93 public: |
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94 RSqlDriveSpaceCol(); |
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95 void Create(RFs& aFs); |
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96 void ResetAndDestroy(); |
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97 CSqlDriveSpace* Find(TDriveNumber aDrive); |
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98 CSqlDriveSpace* AddL(TDriveNumber aDrive); |
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99 void Invariant() const; |
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100 |
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101 private: |
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102 RFs* iFs; //File session reference |
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103 RPointerArray<CSqlDriveSpace> iDriveSpaceCol; //Collection of CSqlDriveSpace objects: one per drive |
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104 |
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105 }; |
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106 |
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107 #endif//__SQLSRVDRIVESPACE_H__ |