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1 /**************************************************************************** |
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2 ** |
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3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). |
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4 ** All rights reserved. |
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5 ** Contact: Nokia Corporation (qt-info@nokia.com) |
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6 ** |
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7 ** This file is part of the test suite of the Qt Toolkit. |
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8 ** |
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9 ** $QT_BEGIN_LICENSE:LGPL$ |
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10 ** No Commercial Usage |
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11 ** This file contains pre-release code and may not be distributed. |
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12 ** You may use this file in accordance with the terms and conditions |
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13 ** contained in the Technology Preview License Agreement accompanying |
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14 ** this package. |
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15 ** |
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16 ** GNU Lesser General Public License Usage |
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17 ** Alternatively, this file may be used under the terms of the GNU Lesser |
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18 ** General Public License version 2.1 as published by the Free Software |
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19 ** Foundation and appearing in the file LICENSE.LGPL included in the |
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20 ** packaging of this file. Please review the following information to |
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21 ** ensure the GNU Lesser General Public License version 2.1 requirements |
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22 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. |
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23 ** |
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24 ** In addition, as a special exception, Nokia gives you certain additional |
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25 ** rights. These rights are described in the Nokia Qt LGPL Exception |
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26 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. |
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27 ** |
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28 ** If you have questions regarding the use of this file, please contact |
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29 ** Nokia at qt-info@nokia.com. |
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30 ** |
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31 ** |
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32 ** |
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33 ** |
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34 ** |
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35 ** |
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36 ** |
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37 ** |
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38 ** $QT_END_LICENSE$ |
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39 ** |
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40 ****************************************************************************/ |
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41 |
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42 |
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43 #include "qsystemlock.h" |
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44 #include "qsystemlock_p.h" |
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45 #include <qdebug.h> |
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46 #include <QtCore> |
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47 QSystemLockPrivate::QSystemLockPrivate() : |
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48 semaphore(0), semaphoreLock(0), |
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49 lockCount(0), error(QSystemLock::NoError) |
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50 { |
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51 } |
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52 |
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53 void QSystemLockPrivate::setErrorString(const QString &function) |
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54 { |
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55 BOOL windowsError = GetLastError(); |
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56 if (windowsError == 0) |
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57 return; |
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58 errorString = function + QLatin1String(": ") |
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59 + QLatin1String("Unknown error"); |
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60 error = QSystemLock::UnknownError; |
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61 qWarning() << errorString << "key" << key << (int)windowsError << semaphore << semaphoreLock; |
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62 } |
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63 |
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64 /*! |
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65 \internal |
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66 |
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67 Setup the semaphore |
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68 */ |
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69 HANDLE QSystemLockPrivate::handle() |
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70 { |
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71 // don't allow making handles on empty keys |
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72 if (key.isEmpty()) |
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73 return 0; |
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74 |
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75 // Create it if it doesn't already exists. |
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76 if (semaphore == 0) { |
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77 QString safeName = makeKeyFileName(); |
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78 semaphore = CreateSemaphore(0, MAX_LOCKS, MAX_LOCKS, (wchar_t*)safeName.utf16()); |
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79 |
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80 if (semaphore == 0) { |
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81 setErrorString(QLatin1String("QSystemLockPrivate::handle")); |
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82 return 0; |
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83 } |
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84 } |
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85 |
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86 if (semaphoreLock == 0) { |
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87 QString safeLockName = QSharedMemoryPrivate::makePlatformSafeKey(key + QLatin1String("lock"), QLatin1String("qipc_systemlock_")); |
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88 semaphoreLock = CreateSemaphore(0, 1, 1, (wchar_t*)safeLockName.utf16()); |
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89 |
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90 if (semaphoreLock == 0) { |
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91 setErrorString(QLatin1String("QSystemLockPrivate::handle")); |
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92 return 0; |
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93 } |
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94 } |
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95 |
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96 return semaphore; |
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97 } |
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98 |
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99 /*! |
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100 \internal |
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101 |
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102 Cleanup the semaphore |
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103 */ |
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104 void QSystemLockPrivate::cleanHandle() |
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105 { |
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106 if (semaphore && !CloseHandle(semaphore)) |
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107 setErrorString(QLatin1String("QSystemLockPrivate::cleanHandle:")); |
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108 if (semaphoreLock && !CloseHandle(semaphoreLock)) |
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109 setErrorString(QLatin1String("QSystemLockPrivate::cleanHandle:")); |
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110 semaphore = 0; |
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111 semaphoreLock = 0; |
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112 } |
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113 |
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114 bool QSystemLockPrivate::lock(HANDLE handle, int count) |
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115 { |
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116 if (count == 1) { |
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117 WaitForSingleObject(handle, INFINITE); |
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118 return true; |
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119 } |
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120 |
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121 int i = count; |
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122 while (i > 0) { |
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123 if (WAIT_OBJECT_0 == WaitForSingleObject(handle, 0)) { |
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124 --i; |
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125 } else { |
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126 // undo what we have done, sleep and then try again later |
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127 ReleaseSemaphore(handle, (count - i), 0); |
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128 i = count; |
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129 ReleaseSemaphore(semaphoreLock, 1, 0); |
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130 Sleep(1); |
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131 WaitForSingleObject(semaphoreLock, INFINITE); |
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132 } |
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133 } |
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134 return true; |
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135 } |
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136 |
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137 bool QSystemLockPrivate::unlock(HANDLE handle, int count) |
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138 { |
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139 if (0 == ReleaseSemaphore(handle, count, 0)) { |
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140 setErrorString(QLatin1String("QSystemLockPrivate::unlock")); |
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141 return false; |
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142 } |
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143 return true; |
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144 } |
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145 |
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146 /*! |
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147 \internal |
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148 |
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149 modifySemaphore handles recursive behavior and modifies the semaphore. |
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150 */ |
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151 bool QSystemLockPrivate::modifySemaphore(QSystemLockPrivate::Operation op, |
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152 QSystemLock::LockMode mode) |
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153 { |
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154 if (0 == handle()) |
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155 return false; |
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156 |
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157 if ((lockCount == 0 && op == Lock) || (lockCount > 0 && op == Unlock)) { |
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158 if (op == Unlock) { |
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159 --lockCount; |
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160 Q_ASSERT(lockCount >= 0); |
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161 if (lockCount > 0) |
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162 return true; |
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163 } |
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164 |
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165 int count = (mode == QSystemLock::ReadWrite) ? MAX_LOCKS : 1; |
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166 if (op == Lock) { |
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167 lock(semaphoreLock, 1); |
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168 lock(semaphore, count); |
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169 if (count != MAX_LOCKS) unlock(semaphoreLock, 1); |
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170 lockedMode = mode; |
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171 } else { |
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172 if (count == MAX_LOCKS) unlock(semaphoreLock, 1); |
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173 unlock(semaphore, count); |
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174 } |
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175 |
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176 } |
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177 if (op == Lock) |
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178 lockCount++; |
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179 |
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180 return true; |
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181 } |
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182 |