1 /* |
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2 * Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies). |
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3 * All rights reserved. |
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4 * |
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5 * This program is free software: you can redistribute it and/or modify |
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6 * it under the terms of the GNU Lesser General Public License as published by |
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7 * the Free Software Foundation, version 2.1 of the License. |
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8 * |
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9 * This program is distributed in the hope that it will be useful, |
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10 * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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12 * GNU Lesser General Public License for more details. |
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13 * |
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14 * You should have received a copy of the GNU Lesser General Public License |
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15 * along with this program. If not, |
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16 * see "http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html/". |
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17 * |
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18 * Description: |
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19 * |
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20 */ |
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21 |
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22 #include "qsignalintercepter.h" |
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23 #include <qmetaobject.h> |
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24 #include <qmetatype.h> |
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25 #include <qobjectdefs.h> |
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26 |
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27 /*! |
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28 \class QSignalIntercepter |
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29 \inpublicgroup QtBaseModule |
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30 |
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31 \brief The QSignalIntercepter class provides an interface for intercepting signals as meta-calls |
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32 |
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33 IPC mechanisms need to intercept signals and convert them into protocol |
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34 messages, but it is generally impractical to create a slot for every |
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35 signal that needs to be dispatched. The QSignalIntercepter class allows |
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36 signals to be intercepted as meta-calls so that IPC dispatching can |
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37 be implemented in a generic fashion. |
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38 |
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39 The activated() method is called whenever the signal is emitted, |
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40 with the arguments in a typed list. |
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41 |
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42 \sa QSlotInvoker |
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43 |
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44 \ingroup objectmodel |
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45 */ |
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46 |
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47 class QSignalIntercepterPrivate |
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48 { |
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49 public: |
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50 QObject *sender; |
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51 QByteArray signal; |
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52 int signalIndex; |
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53 int destroyIndex; |
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54 int slotIndex; |
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55 int *types; |
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56 int numArgs; |
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57 |
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58 ~QSignalIntercepterPrivate() |
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59 { |
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60 if ( types ) |
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61 qFree( types ); |
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62 } |
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63 }; |
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64 |
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65 /*! |
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66 Create a new signal intercepter which traps \a signal on \a sender. |
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67 The object will be attached to \a parent, if present. |
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68 */ |
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69 QSignalIntercepter::QSignalIntercepter |
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70 ( QObject *sender, const QByteArray& signal, QObject *parent ) |
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71 : QObject( parent ) |
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72 { |
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73 // Initialize the private members. |
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74 d = new QSignalIntercepterPrivate(); |
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75 d->sender = sender; |
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76 d->signal = signal; |
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77 d->signalIndex = -1; |
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78 d->destroyIndex = -1; |
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79 d->slotIndex = -1; |
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80 d->types = 0; |
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81 |
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82 // Resolve the indices of the signals we are interested in. |
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83 if ( sender && signal.size() > 0 ) { |
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84 // '2' is QSIGNAL_CODE in Qt 4.4 and below, |
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85 // '6' is QSIGNAL_CODE in Qt 4.5 and higher. |
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86 if ( signal[0] != '2' && signal[0] != '6' ) { |
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87 qWarning( "QSignalIntercepter: `%s' is not a valid signal " |
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88 "specification", signal.constData() ); |
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89 return; |
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90 } |
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91 QByteArray name = QMetaObject::normalizedSignature |
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92 ( signal.constData() + 1 ); |
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93 d->signalIndex |
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94 = sender->metaObject()->indexOfSignal( name.constData() ); |
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95 if ( d->signalIndex < 0 ) { |
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96 qWarning( "QSignalIntercepter: no such signal: %s::%s", |
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97 sender->metaObject()->className(), signal.constData() ); |
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98 return; |
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99 } |
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100 d->destroyIndex |
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101 = sender->metaObject()->indexOfSignal( "destroyed()" ); |
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102 d->types = connectionTypes( name, d->numArgs ); |
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103 } |
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104 |
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105 // Derive a fake slot index to use in our manual qt_metacall implementation. |
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106 d->slotIndex = staticMetaObject.methodCount(); |
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107 |
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108 // Connect up the signals. |
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109 if ( d->signalIndex >= 0 ) { |
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110 QMetaObject::connect( sender, d->signalIndex, |
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111 this, d->slotIndex, |
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112 Qt::DirectConnection, 0 ); |
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113 } |
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114 if ( d->destroyIndex >= 0 ) { |
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115 QMetaObject::connect( sender, d->destroyIndex, |
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116 this, d->slotIndex + 1, |
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117 Qt::DirectConnection, 0 ); |
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118 } |
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119 } |
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120 |
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121 /*! |
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122 Destroy a signal intercepter. |
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123 */ |
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124 QSignalIntercepter::~QSignalIntercepter() |
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125 { |
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126 if ( d->signalIndex >= 0 ) { |
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127 QMetaObject::disconnect( d->sender, d->signalIndex, |
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128 this, d->slotIndex ); |
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129 } |
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130 if ( d->destroyIndex >= 0 ) { |
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131 QMetaObject::disconnect( d->sender, d->destroyIndex, |
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132 this, d->slotIndex + 1 ); |
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133 } |
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134 delete d; |
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135 } |
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136 |
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137 /*! |
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138 Returns the sender that this signal interceptor is attached to. |
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139 */ |
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140 QObject *QSignalIntercepter::sender() const |
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141 { |
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142 return d->sender; |
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143 } |
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144 |
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145 /*! |
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146 Returns the name of the signal that this signal interceptor is attached to. |
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147 */ |
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148 QByteArray QSignalIntercepter::signal() const |
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149 { |
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150 return d->signal; |
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151 } |
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152 |
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153 /*! |
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154 Returns true if this signal intercepter is valid; that is, there was |
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155 a signal present with the specified parameters when this object |
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156 was constructed. |
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157 */ |
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158 bool QSignalIntercepter::isValid() const |
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159 { |
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160 return ( d->signalIndex != -1 ); |
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161 } |
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162 |
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163 /*! |
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164 \internal |
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165 */ |
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166 int QSignalIntercepter::qt_metacall(QMetaObject::Call c, int id, void **a) |
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167 { |
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168 id = QObject::qt_metacall(c, id, a); |
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169 if (id < 0) |
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170 return id; |
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171 if (c == QMetaObject::InvokeMetaMethod) { |
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172 switch (id) { |
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173 case 0: { |
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174 // The signal we are interested in has been activated. |
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175 if ( d->types ) { |
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176 QList<QVariant> args; |
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177 for ( int i = 0; i < d->numArgs; ++i ) { |
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178 if ( d->types[i] != QVariantId ) { |
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179 QVariant arg( d->types[i], a[i + 1] ); |
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180 args.append( arg ); |
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181 } else { |
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182 args.append( *((const QVariant *)( a[i + 1] )) ); |
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183 } |
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184 } |
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185 activated( args ); |
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186 } |
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187 } |
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188 break; |
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189 |
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190 case 1: { |
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191 // The sender has been destroyed. Clear the signal indices |
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192 // so that we don't try to do a manual disconnect when our |
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193 // own destructor is called. |
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194 d->signalIndex = -1; |
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195 d->destroyIndex = -1; |
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196 } |
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197 break; |
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198 } |
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199 id -= 2; |
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200 } |
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201 return id; |
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202 } |
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203 |
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204 /*! |
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205 \fn void QSignalIntercepter::activated( const QList<QVariant>& args ) |
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206 |
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207 Called when the signal that is being intercepted is activated. |
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208 The arguments to the signal are passed in the list \a args. |
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209 */ |
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210 |
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211 // Get the QVariant type number for a type name. |
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212 int QSignalIntercepter::typeFromName( const QByteArray& type ) |
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213 { |
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214 int id; |
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215 if (type.endsWith('*')) |
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216 return QMetaType::VoidStar; |
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217 else if ( type.size() == 0 || type == "void" ) |
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218 return QMetaType::Void; |
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219 else if ( type == "QVariant" ) |
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220 return QSignalIntercepter::QVariantId; |
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221 id = QMetaType::type( type.constData() ); |
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222 if ( id != (int)QMetaType::Void ) |
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223 return id; |
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224 return QVariant::nameToType(type); |
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225 } |
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226 |
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227 /*! |
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228 Returns the connection types associated with a signal or slot \a member |
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229 specification. The array of types is returned from this function, |
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230 and the number of arguments is returned in \a nargs. Returns null |
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231 if \a member is invalid. The return value must be freed with qFree(). |
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232 */ |
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233 int *QSignalIntercepter::connectionTypes( const QByteArray& member, int& nargs ) |
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234 { |
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235 // Based on Qt's internal queuedConnectionTypes function. |
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236 nargs = 0; |
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237 int *types = 0; |
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238 const char *s = member.constData(); |
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239 while (*s != '\0' && *s != '(') { ++s; } |
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240 if ( *s == '\0' ) |
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241 return 0; |
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242 ++s; |
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243 const char *e = s; |
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244 while (*e != ')') { |
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245 ++e; |
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246 if (*e == ')' || *e == ',') |
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247 ++nargs; |
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248 } |
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249 |
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250 types = (int *) qMalloc((nargs+1)*sizeof(int)); |
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251 types[nargs] = 0; |
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252 for (int n = 0; n < nargs; ++n) { |
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253 e = s; |
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254 while (*s != ',' && *s != ')') |
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255 ++s; |
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256 QByteArray type(e, s-e); |
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257 ++s; |
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258 |
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259 types[n] = typeFromName(type); |
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260 if (!types[n]) { |
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261 qWarning("QSignalIntercepter::connectionTypes: Cannot marshal arguments of type '%s'", type.data()); |
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262 qFree(types); |
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263 return 0; |
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264 } |
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265 } |
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266 return types; |
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267 } |
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