summaryrefslogtreecommitdiffstats
path: root/src/qml/qml/qqmlboundsignal.cpp
blob: 8fceb94f45aa33906062deb6e7fcbd9f598ba09a (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
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QtQml module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
** Public license version 3 or any later version approved by the KDE Free
** Qt Foundation. The licenses are as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-2.0.html and
** https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qqmlboundsignal_p.h"

#include <private/qmetaobject_p.h>
#include <private/qmetaobjectbuilder_p.h>
#include "qqmlengine_p.h"
#include "qqmlexpression_p.h"
#include "qqmlcontext_p.h"
#include "qqml.h"
#include "qqmlcontext.h"
#include "qqmlglobal_p.h"
#include <private/qqmlprofiler_p.h>
#include <private/qqmldebugconnector_p.h>
#include <private/qqmldebugserviceinterfaces_p.h>
#include "qqmlinfo.h"

#include <private/qjsvalue_p.h>
#include <private/qv4value_p.h>
#include <private/qv4jscall_p.h>
#include <private/qv4qobjectwrapper_p.h>
#include <private/qv4qmlcontext_p.h>

#include <QtCore/qdebug.h>

#include <qtqml_tracepoints_p.h>

QT_BEGIN_NAMESPACE

QQmlBoundSignalExpression::QQmlBoundSignalExpression(
        QObject *target, int index, const QQmlRefPointer<QQmlContextData> &ctxt, QObject *scope,
        const QString &expression, const QString &fileName, quint16 line, quint16 column,
        const QString &handlerName, const QString &parameterString)
    : QQmlJavaScriptExpression(),
      m_index(index),
      m_target(target)
{
    init(ctxt, scope);

    QV4::ExecutionEngine *v4 = engine()->handle();

    QString function;

    // Add some leading whitespace to account for the binding's column offset.
    // It's 2 off because a, we start counting at 1 and b, the '(' below is not counted.
    function += QString(qMax(column, (quint16)2) - 2, QChar(QChar::Space))
              + QLatin1String("(function ") + handlerName + QLatin1Char('(');

    if (parameterString.isEmpty()) {
        QString error;
        //TODO: look at using the property cache here (as in the compiler)
        //      for further optimization
        QMetaMethod signal = QMetaObjectPrivate::signal(m_target->metaObject(), m_index);
        function += QQmlPropertyCache::signalParameterStringForJS(v4, signal.parameterNames(), &error);

        if (!error.isEmpty()) {
            qmlWarning(scopeObject()) << error;
            return;
        }
    } else
        function += parameterString;

    function += QLatin1String(") { ") + expression + QLatin1String(" })");
    QV4::Scope valueScope(v4);
    QV4::ScopedFunctionObject f(valueScope, evalFunction(context(), scopeObject(), function, fileName, line));
    QV4::ScopedContext context(valueScope, f->scope());
    setupFunction(context, f->function());
}

QQmlBoundSignalExpression::QQmlBoundSignalExpression(
        QObject *target, int index, const QQmlRefPointer<QQmlContextData> &ctxt,
        QObject *scopeObject, QV4::Function *function, QV4::ExecutionContext *scope)
    : QQmlJavaScriptExpression(),
      m_index(index),
      m_target(target)
{
    // It's important to call init first, because m_index gets remapped in case of cloned signals.
    init(ctxt, scopeObject);

    QV4::ExecutionEngine *engine = ctxt->engine()->handle();

    // If the function is marked as having a nested function, then the user wrote:
    //   onSomeSignal: function() { /*....*/ }
    // So take that nested function:
    if (auto closure = function->nestedFunction()) {
        function = closure;
    } else {
        QList<QByteArray> signalParameters = QMetaObjectPrivate::signal(m_target->metaObject(), m_index).parameterNames();
        if (!signalParameters.isEmpty()) {
            QString error;
            QQmlPropertyCache::signalParameterStringForJS(engine, signalParameters, &error);
            if (!error.isEmpty()) {
                qmlWarning(scopeObject) << error;
                return;
            }
            function->updateInternalClass(engine, signalParameters);
        }
    }

    QV4::Scope valueScope(engine);
    QV4::Scoped<QV4::QmlContext> qmlContext(valueScope, scope);
    if (!qmlContext)
        qmlContext = QV4::QmlContext::create(engine->rootContext(), ctxt, scopeObject);
    setupFunction(qmlContext, function);
}

void QQmlBoundSignalExpression::init(const QQmlRefPointer<QQmlContextData> &ctxt, QObject *scope)
{
    setNotifyOnValueChanged(false);
    setContext(ctxt);
    setScopeObject(scope);

    Q_ASSERT(m_target && m_index > -1);
    m_index = QQmlPropertyCache::originalClone(m_target, m_index);
}

QQmlBoundSignalExpression::~QQmlBoundSignalExpression()
{
}

QString QQmlBoundSignalExpression::expressionIdentifier() const
{
    QQmlSourceLocation loc = sourceLocation();
    return loc.sourceFile + QLatin1Char(':') + QString::number(loc.line);
}

void QQmlBoundSignalExpression::expressionChanged()
{
    // bound signals do not notify on change.
}

QString QQmlBoundSignalExpression::expression() const
{
    if (expressionFunctionValid())
        return QStringLiteral("function() { [native code] }");
    return QString();
}

// Parts of this function mirror code in QQmlExpressionPrivate::value() and v8value().
// Changes made here may need to be made there and vice versa.
void QQmlBoundSignalExpression::evaluate(void **a)
{
    Q_ASSERT (engine());

    if (!expressionFunctionValid())
        return;

    QQmlEngine *qmlengine = engine();
    QQmlEnginePrivate *ep = QQmlEnginePrivate::get(qmlengine);
    QV4::ExecutionEngine *v4 = qmlengine->handle();
    QV4::Scope scope(v4);

    ep->referenceScarceResources(); // "hold" scarce resources in memory during evaluation.

    QQmlMetaObject::ArgTypeStorage storage;
    //TODO: lookup via signal index rather than method index as an optimization
    int methodIndex = QMetaObjectPrivate::signal(m_target->metaObject(), m_index).methodIndex();
    int *argsTypes = QQmlMetaObject(m_target).methodParameterTypes(methodIndex, &storage, nullptr);
    int argCount = argsTypes ? *argsTypes : 0;

    QV4::JSCallData jsCall(scope, argCount);
    for (int ii = 0; ii < argCount; ++ii) {
        int type = argsTypes[ii + 1];
        //### ideally we would use metaTypeToJS, however it currently gives different results
        //    for several cases (such as QVariant type and QObject-derived types)
        //args[ii] = engine->metaTypeToJS(type, a[ii + 1]);
        if (type == qMetaTypeId<QJSValue>()) {
            jsCall->args[ii] = QJSValuePrivate::convertToReturnedValue(v4, *reinterpret_cast<QJSValue *>(a[ii + 1]));
        } else if (type == QMetaType::QVariant) {
            jsCall->args[ii] = scope.engine->fromVariant(*((QVariant *)a[ii + 1]));
        } else if (type == QMetaType::Int) {
            //### optimization. Can go away if we switch to metaTypeToJS, or be expanded otherwise
            jsCall->args[ii] = QV4::Value::fromInt32(*reinterpret_cast<const int*>(a[ii + 1]));
        } else if (ep->isQObject(type)) {
            if (!*reinterpret_cast<void* const *>(a[ii + 1]))
                jsCall->args[ii] = QV4::Value::nullValue();
            else
                jsCall->args[ii] = QV4::QObjectWrapper::wrap(v4, *reinterpret_cast<QObject* const *>(a[ii + 1]));
        } else {
            jsCall->args[ii] = scope.engine->fromVariant(QVariant(QMetaType(type), a[ii + 1]));
        }
    }

    QQmlJavaScriptExpression::evaluate(jsCall.callData(), nullptr);

    ep->dereferenceScarceResources(); // "release" scarce resources if top-level expression evaluation is complete.
}

void QQmlBoundSignalExpression::evaluate(const QList<QVariant> &args)
{
    Q_ASSERT (engine());

    if (!expressionFunctionValid())
        return;

    QQmlEngine *qmlengine = engine();
    QQmlEnginePrivate *ep = QQmlEnginePrivate::get(qmlengine);
    QV4::Scope scope(qmlengine->handle());

    ep->referenceScarceResources(); // "hold" scarce resources in memory during evaluation.

    QV4::JSCallData jsCall(scope, args.count());
    for (int ii = 0; ii < args.count(); ++ii) {
        jsCall->args[ii] = scope.engine->fromVariant(args[ii]);
    }

    QQmlJavaScriptExpression::evaluate(jsCall.callData(), nullptr);

    ep->dereferenceScarceResources(); // "release" scarce resources if top-level expression evaluation is complete.
}

////////////////////////////////////////////////////////////////////////


/*! \internal
    \a signal MUST be in the signal index range (see QObjectPrivate::signalIndex()).
    This is different from QMetaMethod::methodIndex().
*/
QQmlBoundSignal::QQmlBoundSignal(QObject *target, int signal, QObject *owner,
                                 QQmlEngine *engine)
    : QQmlNotifierEndpoint(QQmlNotifierEndpoint::QQmlBoundSignal),
      m_prevSignal(nullptr), m_nextSignal(nullptr),
      m_enabled(true), m_expression(nullptr)
{
    addToObject(owner);

    /*
        If this is a cloned method, connect to the 'original'. For example,
        for the signal 'void aSignal(int parameter = 0)', if the method
        index refers to 'aSignal()', get the index of 'aSignal(int)'.
        This ensures that 'parameter' will be available from QML.
    */
    signal = QQmlPropertyCache::originalClone(target, signal);
    QQmlNotifierEndpoint::connect(target, signal, engine);
}

QQmlBoundSignal::~QQmlBoundSignal()
{
    removeFromObject();
}

void QQmlBoundSignal::addToObject(QObject *obj)
{
    Q_ASSERT(!m_prevSignal);
    Q_ASSERT(obj);

    QQmlData *data = QQmlData::get(obj, true);

    m_nextSignal = data->signalHandlers;
    if (m_nextSignal) m_nextSignal->m_prevSignal = &m_nextSignal;
    m_prevSignal = &data->signalHandlers;
    data->signalHandlers = this;
}

void QQmlBoundSignal::removeFromObject()
{
    if (m_prevSignal) {
        *m_prevSignal = m_nextSignal;
        if (m_nextSignal) m_nextSignal->m_prevSignal = m_prevSignal;
        m_prevSignal = nullptr;
        m_nextSignal = nullptr;
    }
}

/*!
    Returns the signal expression.
*/
QQmlBoundSignalExpression *QQmlBoundSignal::expression() const
{
    return m_expression.data();
}

/*!
    Sets the signal expression to \a e.

    The QQmlBoundSignal instance takes ownership of \a e (and does not add a reference).
*/
void QQmlBoundSignal::takeExpression(QQmlBoundSignalExpression *e)
{
    m_expression.adopt(e);
    if (m_expression)
        m_expression->setNotifyOnValueChanged(false);
}

/*!
    This property holds whether the item will emit signals.

    The QQmlBoundSignal callback will only emit a signal if this property is set to true.

    By default, this property is true.
 */
void QQmlBoundSignal::setEnabled(bool enabled)
{
    if (m_enabled == enabled)
        return;

    m_enabled = enabled;
}

void QQmlBoundSignal_callback(QQmlNotifierEndpoint *e, void **a)
{
    QQmlBoundSignal *s = static_cast<QQmlBoundSignal*>(e);

    if (!s->m_expression || !s->m_enabled)
        return;

    QV4DebugService *service = QQmlDebugConnector::service<QV4DebugService>();
    if (service)
        service->signalEmitted(QString::fromUtf8(QMetaObjectPrivate::signal(
                                                     s->m_expression->target()->metaObject(),
                                                     s->signalIndex()).methodSignature()));

    QQmlEngine *engine;
    if (s->m_expression && (engine = s->m_expression->engine())) {
        Q_TRACE_SCOPE(QQmlHandlingSignal, engine,
                      s->m_expression->function() ? s->m_expression->function()->name()->toQString() : QString(),
                      s->m_expression->sourceLocation().sourceFile, s->m_expression->sourceLocation().line,
                      s->m_expression->sourceLocation().column);
        QQmlHandlingSignalProfiler prof(QQmlEnginePrivate::get(engine)->profiler,
                                        s->m_expression.data());
        s->m_expression->evaluate(a);
        if (s->m_expression && s->m_expression->hasError()) {
            QQmlEnginePrivate::warning(engine, s->m_expression->error(engine));
        }
    }
}

////////////////////////////////////////////////////////////////////////

QQmlPropertyObserver::QQmlPropertyObserver(QQmlBoundSignalExpression *expr)
    : QPropertyObserver([](QPropertyObserver *self, QUntypedPropertyData *) {
                           auto This = static_cast<QQmlPropertyObserver*>(self);
                           This->expression->evaluate(QList<QVariant>());
                       })
{
    expression.adopt(expr);
}

QT_END_NAMESPACE