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42 #include "qdbuspendingreply.h"
43 #include "qdbuspendingcall_p.h"
44 #include "qdbusmetatype.h"
49 \class QDBusPendingReply
53 \brief The QDBusPendingReply class contains the reply to an asynchronous method call
55 The QDBusPendingReply is a template class with up to 8 template
56 parameters. Those parameters are the types that will be used to
57 extract the contents of the reply's data.
59 This class is similar in functionality to QDBusReply, but with two
60 important differences:
63 \li QDBusReply accepts exactly one return type, whereas
64 QDBusPendingReply can have from 1 to 8 types
65 \li QDBusReply only works on already completed replies, whereas
66 QDBusPendingReply allows one to wait for replies from pending
70 Where with QDBusReply you would write:
72 \snippet doc/src/snippets/code/src_qdbus_qdbusreply.cpp 0
74 with QDBusPendingReply, the equivalent code (including the blocking
75 wait for the reply) would be:
77 \snippet doc/src/snippets/code/src.qdbus.qdbuspendingreply.cpp 0
79 For method calls that have more than one output argument, with
80 QDBusReply, you would write:
82 \snippet doc/src/snippets/code/src_qdbus_qdbusreply.cpp 1
84 whereas with QDBusPendingReply, all of the output arguments should
85 be template parameters:
87 \snippet doc/src/snippets/code/src.qdbus.qdbuspendingreply.cpp 2
89 QDBusPendingReply objects can be associated with
90 QDBusPendingCallWatcher objects, which emit signals when the reply
93 \sa QDBusPendingCallWatcher, QDBusReply,
94 QDBusAbstractInterface::asyncCall()
98 \fn QDBusPendingReply::QDBusPendingReply()
100 Creates an empty QDBusPendingReply object. Without assigning a
101 QDBusPendingCall object to this reply, QDBusPendingReply cannot do
102 anything. All functions return their failure values.
106 \fn QDBusPendingReply::QDBusPendingReply(const QDBusPendingReply &other)
108 Creates a copy of the \a other QDBusPendingReply object. Just like
109 QDBusPendingCall and QDBusPendingCallWatcher, this QDBusPendingReply
110 object will share the same pending call reference. All copies
111 share the same return values.
115 \fn QDBusPendingReply::QDBusPendingReply(const QDBusPendingCall &call)
117 Creates a QDBusPendingReply object that will take its contents from
118 the \a call pending asynchronous call. This QDBusPendingReply object
119 will share the same pending call reference as \a call.
123 \fn QDBusPendingReply::QDBusPendingReply(const QDBusMessage &message)
125 Creates a QDBusPendingReply object that will take its contents from
126 the message \a message. In this case, this object will be already
127 in its finished state and the reply's contents will be accessible.
133 \fn QDBusPendingReply &QDBusPendingReply::operator=(const QDBusPendingReply &other)
135 Makes a copy of \a other and drops the reference to the current
136 pending call. If the current reference is to an unfinished pending
137 call and this is the last reference, the pending call will be
138 canceled and there will be no way of retrieving the reply's
139 contents, when they arrive.
143 \fn QDBusPendingReply &QDBusPendingReply::operator=(const QDBusPendingCall &call)
145 Makes this object take its contents from the \a call pending call
146 and drops the reference to the current pending call. If the
147 current reference is to an unfinished pending call and this is the
148 last reference, the pending call will be canceled and there will
149 be no way of retrieving the reply's contents, when they arrive.
153 \fn QDBusPendingReply &QDBusPendingReply::operator=(const QDBusMessage &message)
155 Makes this object take its contents from the \a message message
156 and drops the reference to the current pending call. If the
157 current reference is to an unfinished pending call and this is the
158 last reference, the pending call will be canceled and there will
159 be no way of retrieving the reply's contents, when they arrive.
161 After this function is finished, the QDBusPendingReply object will
162 be in its "finished" state and the \a message contents will be
169 \fn int QDBusPendingReply::count() const
171 Return the number of arguments the reply is supposed to have. This
172 number matches the number of non-void template parameters in this
175 If the reply arrives with a different number of arguments (or with
176 different types), it will be transformed into an error reply
177 indicating a bad signature.
181 \fn QVariant QDBusPendingReply::argumentAt(int index) const
183 Returns the argument at position \a index in the reply's
184 contents. If the reply doesn't have that many elements, this
185 function's return value is undefined (will probably cause an
186 assertion failure), so it is important to verify that the
187 processing is finished and the reply is valid.
191 \fn Type QDBusPendingReply::argumentAt() const
193 Returns the argument at position \c Index (which is a template
194 parameter) cast to type \c Type. This function uses template code
195 to determine the proper \c Type type, according to the type list
196 used in the construction of this object.
198 Note that, if the reply hasn't arrived, this function causes the
199 calling thread to block until the reply is processed.
203 \fn T1 QDBusPendingReply::value() const
205 Returns the first argument in this reply, cast to type \c T1 (the
206 first template parameter of this class). This is equivalent to
207 calling argumentAt<0>().
209 This function is provided as a convenience, matching the
210 QDBusReply::value() function.
212 Note that, if the reply hasn't arrived, this function causes the
213 calling thread to block until the reply is processed.
217 \fn QDBusPendingReply::operator T1() const
219 Returns the first argument in this reply, cast to type \c T1 (the
220 first template parameter of this class). This is equivalent to
221 calling argumentAt<0>().
223 This function is provided as a convenience, matching the
224 QDBusReply::value() function.
226 Note that, if the reply hasn't arrived, this function causes the
227 calling thread to block until the reply is processed.
231 \fn void QDBusPendingReply::waitForFinished()
233 Suspends the execution of the calling thread until the reply is
234 received and processed. After this function returns, isFinished()
235 should return true, indicating the reply's contents are ready to
238 \sa QDBusPendingCallWatcher::waitForFinished()
241 QDBusPendingReplyData::QDBusPendingReplyData()
242 : QDBusPendingCall(0) // initialize base class empty
246 QDBusPendingReplyData::~QDBusPendingReplyData()
250 void QDBusPendingReplyData::assign(const QDBusPendingCall &other)
252 QDBusPendingCall::operator=(other);
255 void QDBusPendingReplyData::assign(const QDBusMessage &message)
257 d = new QDBusPendingCallPrivate(QDBusMessage(), 0); // drops the reference to the old one
258 d->replyMessage = message;
261 QVariant QDBusPendingReplyData::argumentAt(int index) const
264 d->waitForFinished(); // bypasses "const"
266 Q_ASSERT_X(d && index >= 0 && index < d->replyMessage.arguments().count(),
267 "QDBusPendingReply::argumentAt",
268 "Index out of bounds");
270 return d->replyMessage.arguments().at(index);
273 void QDBusPendingReplyData::setMetaTypes(int count, const int *types)
276 QMutexLocker locker(&d->mutex);
277 d->setMetaTypes(count, types);
278 d->checkReceivedSignature();