summaryrefslogtreecommitdiffstats
path: root/src/declarative/util/qdeclarativeconnections.cpp
blob: ffa160f67bfafd6e60b676ee88ce06f5c89a2a9b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
/****************************************************************************
**
** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtDeclarative module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the Technology Preview License Agreement accompanying
** this package.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights.  These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "private/qdeclarativeconnections_p.h"

#include <qdeclarativeexpression.h>
#include <qdeclarativeproperty_p.h>
#include <qdeclarativeboundsignal_p.h>
#include <qdeclarativecontext.h>
#include <qdeclarativeinfo.h>

#include <QtCore/qdebug.h>
#include <QtCore/qstringlist.h>

#include <private/qobject_p.h>

QT_BEGIN_NAMESPACE

class QDeclarativeConnectionsPrivate : public QObjectPrivate
{
public:
    QDeclarativeConnectionsPrivate() : target(0), targetSet(false), ignoreUnknownSignals(false), componentcomplete(true) {}

    QList<QDeclarativeBoundSignal*> boundsignals;
    QObject *target;

    bool targetSet;
    bool ignoreUnknownSignals;
    bool componentcomplete;

    QByteArray data;
};

/*!
    \qmlclass Connections QDeclarativeConnections
  \since 4.7
    \brief A Connections object describes generalized connections to signals.

    When connecting to signals in QML, the usual way is to create an
    "on<Signal>" handler that reacts when a signal is received, like this:

    \qml
    MouseArea {
        onClicked: { foo(...) }
    }
    \endqml

    However, in some cases, it is not possible to connect to a signal in this
    way, such as:

    \list
        \i multiple connections to the same signal
        \i connections outside the scope of the signal sender
        \i connections to targets not defined in QML
    \endlist

    When any of these are needed, the Connections object can be used instead.

    For example, the above code can be changed to use a Connections object,
    like this:

    \qml
    MouseArea {
        Connections {
            onClicked: foo(...)
        }
    }
    \endqml

    More generally, the Connections object can be a child of some other object than
    the sender of the signal:

    \qml
    MouseArea {
        id: area
    }
    ...
    Connections {
        target: area
        onClicked: foo(...)
    }
    \endqml

    \sa QtDeclarative
*/

/*!
    \internal
    \class QDeclarativeConnections
    \brief The QDeclarativeConnections class describes generalized connections to signals.

*/
QDeclarativeConnections::QDeclarativeConnections(QObject *parent) :
    QObject(*(new QDeclarativeConnectionsPrivate), parent)
{
}

QDeclarativeConnections::~QDeclarativeConnections()
{
}

/*!
    \qmlproperty Object Connections::target
    This property holds the object that sends the signal.

    If not set at all, the target defaults to be the parent of the Connections.

    If set to null, no connection is made and any signal handlers are ignored
    until the target is not null.
*/
QObject *QDeclarativeConnections::target() const
{
    Q_D(const QDeclarativeConnections);
    return d->targetSet ? d->target : parent();
}

void QDeclarativeConnections::setTarget(QObject *obj)
{
    Q_D(QDeclarativeConnections);
    d->targetSet = true; // even if setting to 0, it is *set*
    if (d->target == obj)
        return;
    foreach (QDeclarativeBoundSignal *s, d->boundsignals) {
        // It is possible that target is being changed due to one of our signal
        // handlers -> use deleteLater().
        if (s->isEvaluating())
            s->deleteLater();
        else
            delete s;
    }
    d->boundsignals.clear();
    d->target = obj;
    connectSignals();
    emit targetChanged();
}

/*!
    \qmlproperty bool Connections::ignoreUnknownSignals

    Normally, you will get a runtime error if you try to connect
    to signals on an object which the object does not have.

    By setting this flag to true, such errors are ignored. This is
    useful if you intend to connect to different types of object, handling
    a different set of signals for each.
*/
bool QDeclarativeConnections::ignoreUnknownSignals() const
{
    Q_D(const QDeclarativeConnections);
    return d->ignoreUnknownSignals;
}

void QDeclarativeConnections::setIgnoreUnknownSignals(bool ignore)
{
    Q_D(QDeclarativeConnections);
    d->ignoreUnknownSignals = ignore;
}



QByteArray
QDeclarativeConnectionsParser::compile(const QList<QDeclarativeCustomParserProperty> &props)
{
    QByteArray rv;
    QDataStream ds(&rv, QIODevice::WriteOnly);

    for(int ii = 0; ii < props.count(); ++ii)
    {
        QString propName = QString::fromUtf8(props.at(ii).name());
        if (!propName.startsWith(QLatin1String("on")) || !propName.at(2).isUpper()) {
            error(props.at(ii), QDeclarativeConnections::tr("Cannot assign to non-existent property \"%1\"").arg(propName));
            return QByteArray();
        }

        QList<QVariant> values = props.at(ii).assignedValues();

        for (int i = 0; i < values.count(); ++i) {
            const QVariant &value = values.at(i);

            if (value.userType() == qMetaTypeId<QDeclarativeCustomParserNode>()) {
                error(props.at(ii), QDeclarativeConnections::tr("Connections: nested objects not allowed"));
                return QByteArray();
            } else if (value.userType() == qMetaTypeId<QDeclarativeCustomParserProperty>()) {
                error(props.at(ii), QDeclarativeConnections::tr("Connections: syntax error"));
                return QByteArray();
            } else {
                QDeclarativeParser::Variant v = qvariant_cast<QDeclarativeParser::Variant>(value);
                if (v.isScript()) {
                    ds << propName;
                    ds << v.asScript();
                } else {
                    error(props.at(ii), QDeclarativeConnections::tr("Connections: script expected"));
                    return QByteArray();
                }
            }
        }
    }

    return rv;
}

void QDeclarativeConnectionsParser::setCustomData(QObject *object,
                                            const QByteArray &data)
{
    QDeclarativeConnectionsPrivate *p =
        static_cast<QDeclarativeConnectionsPrivate *>(QObjectPrivate::get(object));
    p->data = data;
}


void QDeclarativeConnections::connectSignals()
{
    Q_D(QDeclarativeConnections);
    if (!d->componentcomplete || (d->targetSet && !target()))
        return;

    QDataStream ds(d->data);
    while (!ds.atEnd()) {
        QString propName;
        ds >> propName;
        QString script;
        ds >> script;
        QDeclarativeProperty prop(target(), propName);
        if (prop.isValid() && (prop.type() & QDeclarativeProperty::SignalProperty)) {
            QDeclarativeBoundSignal *signal =
                new QDeclarativeBoundSignal(target(), prop.method(), this);
            signal->setExpression(new QDeclarativeExpression(qmlContext(this), script, 0));
            d->boundsignals += signal;
        } else {
            if (!d->ignoreUnknownSignals)
                qmlInfo(this) << tr("Cannot assign to non-existent property \"%1\"").arg(propName);
        }
    }
}

void QDeclarativeConnections::classBegin()
{
    Q_D(QDeclarativeConnections);
    d->componentcomplete=false;
}

void QDeclarativeConnections::componentComplete()
{
    Q_D(QDeclarativeConnections);
    d->componentcomplete=true;
    connectSignals();
}

QT_END_NAMESPACE