1 /* |
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2 * Copyright (c) 2008-2009 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 "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: Task manager for multiple tasks. Allows asynchronosity and |
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15 * tracking/callback for long running tasks. |
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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 /** |
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22 * @internal reviewed 30/07/2007 by Simon Brooks |
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23 */ |
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24 |
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25 #ifndef C_GLXTNTASKMANAGER_H |
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26 #define C_GLXTNTASKMANAGER_H |
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27 |
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28 #include "glxtnstd.h" |
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29 #include <glxmediaid.h> |
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30 #include <e32base.h> |
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31 |
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32 // Forward declarations |
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33 class CGlxtnTask; |
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34 class MGlxtnThumbnailStorage; |
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35 |
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36 /** |
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37 * Active object which maintains a priority queue of long running tasks, and |
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38 * provides callback upon task completion or error. |
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39 * |
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40 * The highest priority task in the queue which has @ref CGlxtnTask::TState "state" |
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41 * EStarting is started and the task manager's RunL then delegates to the task's |
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42 * RunL until the task is complete, or is cancelled. The task is then deleted |
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43 * and another task is started, if any are ready to start. |
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44 * |
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45 * The task manager's DoCancel and RunError methods also delegate to the current |
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46 * task, if any. |
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47 * |
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48 * @ingroup glx_thumbnail_creator |
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49 */ |
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50 NONSHARABLE_CLASS(CGlxtnTaskManager) : public CActive |
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51 { |
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52 public: |
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53 enum TExecutionOrder |
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54 { |
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55 ELastOut, // Old tasks with the same priority get executed before the new task |
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56 EFirstOut // New task gets executed before other tasks with the same priority |
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57 }; |
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58 public: |
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59 /** |
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60 * Static constructor. |
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61 */ |
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62 static CGlxtnTaskManager* NewL(); |
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63 |
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64 /** |
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65 * Destructor. |
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66 */ |
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67 ~CGlxtnTaskManager(); |
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68 |
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69 public: |
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70 /** |
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71 * @returns CVieTask task at an index |
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72 */ |
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73 |
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74 inline CGlxtnTask* Task(TInt aIndex) const { return iTasks[aIndex]; }; |
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75 |
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76 /** |
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77 * Returns the highest priority task with the id. |
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78 * If there are multiple tasks with same id and priority, |
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79 * returns the one of those that will be executed first |
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80 */ |
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81 CGlxtnTask* Task(const TGlxtnTaskId& aId) const; |
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82 |
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83 /** |
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84 * Adds a task to the task list. If no task is currently running, the task |
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85 * is started. |
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86 * |
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87 * @param aTask Task to add. Takes ownership, task is deleted if a leave occurs. |
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88 * |
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89 * @param aExecutionOrder -if ELastOut, the tast gets added to the bottom |
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90 * of the queue of the tasks with the same priority |
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91 * as the new tasks. This means that the task is |
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92 * executed after the previously added tasks (with |
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93 * same priority) have been run. |
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94 * -if EFirstOut, the task gets added to the top, |
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95 * and will be executed before the other tasks |
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96 * with the same priority (unless more tasks added |
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97 * later, of course) |
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98 */ |
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99 void AddTaskL(CGlxtnTask* aTask, TExecutionOrder aExecutionOrder = ELastOut); |
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100 |
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101 /** |
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102 * Cancel all tasks relating to a given media item. |
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103 * @param aItemId ID of media item. |
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104 */ |
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105 void CancelTasks(const TGlxMediaId& aItemId); |
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106 |
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107 /** |
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108 * Cancel all tasks using a given storage. |
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109 * @param aClient Reference to thumbnail storage. |
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110 */ |
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111 void CancelTasks(MGlxtnThumbnailStorage* aStorage); |
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112 |
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113 /** |
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114 * Gets the total task count |
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115 * |
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116 * @return TInt task count |
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117 */ |
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118 inline TInt TaskCount() const { return iTasks.Count(); }; |
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119 |
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120 protected: |
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121 /** |
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122 * Constructors |
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123 */ |
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124 CGlxtnTaskManager(); |
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125 void ConstructL(); |
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126 |
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127 private: // From CActive |
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128 void RunL(); |
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129 void DoCancel(); |
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130 TInt RunError(TInt aError); |
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131 |
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132 private: |
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133 /** |
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134 * Issue a self-completing request causing RunL to be called. |
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135 */ |
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136 void AsyncRun(); |
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137 |
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138 private: |
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139 /** |
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140 * Task list in priority order |
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141 */ |
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142 RPointerArray<CGlxtnTask> iTasks; |
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143 |
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144 /** |
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145 * Task that is currently being run. |
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146 */ |
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147 CGlxtnTask* iCurrentTask; |
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148 }; |
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149 |
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150 #endif // C_GLXTNTASKMANAGER_H |
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