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1 /* |
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2 * Copyright (c) 2007-2009 Nokia Corporation and/or its subsidiary(-ies). |
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3 * All rights reserved. |
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4 * This component and the accompanying materials are made available |
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5 * under the terms of the License "Eclipse Public License v1.0" |
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6 * which accompanies this distribution, and is available |
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7 * at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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8 * |
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9 * Initial Contributors: |
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10 * Nokia Corporation - initial contribution. |
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11 * |
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12 * Contributors: |
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13 * |
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14 * Description: |
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15 * Base class functionality for server-side asynchronous requests. |
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16 * |
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17 */ |
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18 |
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19 |
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20 /** |
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21 @file |
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22 */ |
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23 |
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24 |
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25 #include <scs/scsserver.h> |
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26 #include "scsserverconstants.h" |
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27 |
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28 EXPORT_C CAsyncRequest::CAsyncRequest(CScsSession* aSession, CScsSubsession* aSubsession, const RMessage2& aMessage) |
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29 /** |
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30 Record the session, subsession, and function associated with this request. |
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31 These are required to complete or to cancel the request later. |
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32 |
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33 Adds this object to the active scheduler. |
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34 |
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35 @param aSession Session used to launch this request. |
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36 @param aSubsession Subsession on which this request is queued. This |
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37 should be NULL if the request is relative to a session, |
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38 instead of a subsession |
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39 @param aMessage Handle to the kernel-side request object, which |
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40 will be completed later. |
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41 */ |
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42 : CActive(CActive::EPriorityStandard), |
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43 iSession(aSession), |
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44 iSubsession(aSubsession), |
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45 iMessagePtr2(aMessage) |
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46 { |
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47 // extract implementation function |
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48 ScsImpl::ExtractScsAndImplFunctions(aMessage, NULL, &iFunction); |
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49 |
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50 CActiveScheduler::Add(this); |
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51 } |
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52 |
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53 EXPORT_C void CAsyncRequest::TransferToScsFrameworkL() |
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54 /** |
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55 Adds this asynchronous request to the global collection. |
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56 This should be called after the subclass has performed its |
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57 own initialization, but before the active request has been |
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58 set up. |
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59 */ |
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60 { |
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61 iSession->iServer.AddAsyncRequestL(this); |
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62 } |
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63 |
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64 EXPORT_C void CAsyncRequest::RunL() |
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65 /** |
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66 Implement CActive by completing the server client's request status |
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67 with the AO error code, i.e. iStatus. This function also marks this |
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68 object for deletion. |
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69 |
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70 If a subclass overrides this implementation then it must call |
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71 CompleteAndMarkForDeletion itself to complete the client-side |
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72 request. |
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73 |
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74 @see CompleteAndMarkForDeletion |
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75 */ |
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76 { |
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77 TInt r = iStatus.Int(); |
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78 CompleteAndMarkForDeletion(r); |
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79 } |
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80 |
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81 EXPORT_C TInt CAsyncRequest::RunError(TInt aError) |
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82 /** |
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83 Override CActive by completing the request with the |
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84 supplied error code and marking this object for deletion. |
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85 The default implementation of RunL cannot leave, but the |
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86 subclass may override it with a more complex implementation. |
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87 |
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88 @param aError Error code with which aError left. |
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89 @return KErrNone, meaning do not propagate |
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90 the error to the active scheduler. |
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91 */ |
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92 { |
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93 CompleteAndMarkForDeletion(aError); |
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94 return KErrNone; |
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95 } |
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96 |
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97 void CAsyncRequest::CancelCompleteAndMarkForDeletion() |
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98 /** |
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99 Cancel this asynchronous request and complete the client |
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100 request with KErrCancel. On exit, this object has been |
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101 marked for deletion. |
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102 */ |
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103 { |
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104 CompleteAndMarkForDeletion(KErrCancel); |
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105 } |
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106 |
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107 EXPORT_C void CAsyncRequest::CompleteAndMarkForDeletion(TInt aError) |
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108 /** |
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109 Completes the client-side request associated with this |
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110 asynchronous request and marks this object for deletion. |
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111 |
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112 If the error was because the client passed a bad descriptor then |
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113 panick the client instead of completing the request for consistency |
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114 with synchronous requests. |
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115 |
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116 @param aError Error code with which the client request |
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117 will be completed. |
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118 */ |
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119 { |
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120 if (aError == KErrBadDescriptor) |
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121 PanicClient(iMessagePtr2, ScsImpl::EScsClBadDesc); |
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122 else |
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123 iMessagePtr2.Complete(aError); |
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124 MarkForDeletion(); |
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125 } |
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126 |
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127 void CAsyncRequest::MarkForDeletion() |
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128 /** |
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129 Mark this outstanding request for deletion, so it is |
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130 cleaned up when the cleanup AO runs. |
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131 */ |
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132 { |
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133 DoCleanup(); |
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134 // The deletion is processed at priority CActive::EPriorityHigh, |
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135 // so should happen ahead of any pending or new requests. |
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136 CAsyncCallBack* acb = iSession->iServer.iAsyncCleanup; |
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137 acb->CallBack(); // no effect if already queued |
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138 iSession = NULL; // mark for deletion |
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139 } |
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140 |
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141 EXPORT_C void CAsyncRequest::DoCleanup() |
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142 /** |
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143 This virtual function is called whenever the SCS needs to cancel an operation. |
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144 |
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145 If the asynchronous request implementation ALWAYS has an internal request active |
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146 for the duration of the client request, then this default implementation can be used, which |
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147 simply calls CActive::Cancel which will call the derived classe's DoCancel (if, and only if |
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148 the object IsActive). |
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149 |
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150 A more complex case is where the asynchronous requests may enter an internal queue where |
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151 the client request is (obviously still active), but the derived class has not outstanding request. |
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152 In this case the default implementation will cause a HANG, because Cancel will not call DoCancel if |
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153 the object is not active... |
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154 |
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155 In the generic case, the derived class should provide an overload for the Cleanup method. |
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156 This function should call Cancel to cancel any outstanding operation, then perform whatever other |
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157 cleanup is required to cleanup the request (closing handles, removing from queues etc). |
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158 The framework will then complete the client request. |
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159 |
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160 nb. The destructor of the CAsyncRequest may not run until sometime after the client request has been |
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161 completed. |
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162 */ |
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163 { |
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164 Cancel(); |
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165 } |
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166 |