summaryrefslogtreecommitdiffstats
path: root/src/declarative/qml/qdeclarativecomponent.cpp
blob: fc393d1e5e31e6864930a9ea285985086a74f65f (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
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
/****************************************************************************
**
** Copyright (C) 2011 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 "qdeclarativecomponent.h"
#include "private/qdeclarativecomponent_p.h"

#include "private/qdeclarativecompiler_p.h"
#include "private/qdeclarativecontext_p.h"
#include "private/qdeclarativeengine_p.h"
#include "private/qdeclarativevme_p.h"
#include "qdeclarative.h"
#include "qdeclarativeengine.h"
#include "private/qdeclarativebinding_p.h"
#include "private/qdeclarativebinding_p_p.h"
#include "private/qdeclarativeglobal_p.h"
#include "private/qdeclarativescriptparser_p.h"
#include "private/qdeclarativedebugtrace_p.h"
#include "private/qdeclarativeenginedebug_p.h"
#include <QtScript/qscriptvalueiterator.h>

#include <QStack>
#include <QStringList>
#include <QtCore/qdebug.h>
#include <QApplication>
#include <qdeclarativeinfo.h>

QT_BEGIN_NAMESPACE

class QByteArray;

/*!
    \class QDeclarativeComponent
    \since 4.7
    \brief The QDeclarativeComponent class encapsulates a QML component definition.
    \mainclass

    Components are reusable, encapsulated QML elements with well-defined interfaces.
    They are often defined in \l {qdeclarativedocuments.html}{Component Files}.

    A QDeclarativeComponent instance can be created from a QML file.
    For example, if there is a \c main.qml file like this:

    \qml
    import QtQuick 1.0

    Item {
        width: 200
        height: 200
    }
    \endqml

    The following code loads this QML file as a component, creates an instance of
    this component using create(), and then queries the \l Item's \l {Item::}{width}
    value:

    \code
    QDeclarativeEngine *engine = new QDeclarativeEngine;
    QDeclarativeComponent component(engine, QUrl::fromLocalFile("main.qml"));

    QObject *myObject = component.create();
    QDeclarativeItem *item = qobject_cast<QDeclarativeItem*>(myObject);
    int width = item->width();  // width = 200
    \endcode


    \section2 Network Components

    If the URL passed to QDeclarativeComponent is a network resource, or if the QML document references a
    network resource, the QDeclarativeComponent has to fetch the network data before it is able to create
    objects.  In this case, the QDeclarativeComponent will have a \l {QDeclarativeComponent::Loading}{Loading}
    \l {QDeclarativeComponent::status()}{status}.  An application will have to wait until the component
    is \l {QDeclarativeComponent::Ready}{Ready} before calling \l {QDeclarativeComponent::create()}.

    The following example shows how to load a QML file from a network resource.  After creating
    the QDeclarativeComponent, it tests whether the component is loading.  If it is, it connects to the
    QDeclarativeComponent::statusChanged() signal and otherwise calls the \c {continueLoading()} method
    directly. Note that QDeclarativeComponent::isLoading() may be false for a network component if the
    component has been cached and is ready immediately.

    \code
    MyApplication::MyApplication()
    {
        // ...
        component = new QDeclarativeComponent(engine, QUrl("http://www.example.com/main.qml"));
        if (component->isLoading())
            QObject::connect(component, SIGNAL(statusChanged(QDeclarativeComponent::Status)),
                             this, SLOT(continueLoading()));
        else
            continueLoading();
    }

    void MyApplication::continueLoading()
    {
        if (component->isError()) {
            qWarning() << component->errors();
        } else {
            QObject *myObject = component->create();
        }
    }
    \endcode

    \sa {Using QML in C++ Applications}, {Integrating QML with existing Qt UI code}
*/

/*!
    \qmlclass Component QDeclarativeComponent
    \ingroup qml-utility-elements
    \since 4.7
    \brief The Component element encapsulates a QML component definition.

    Components are reusable, encapsulated QML elements with well-defined interfaces.

    Components are often defined by \l {qdeclarativedocuments.html}{component files} -
    that is, \c .qml files. The \e Component element essentially allows QML components
    to be defined inline, within a \l {QML Document}{QML document}, rather than as a separate QML file.
    This may be useful for reusing a small component within a QML file, or for defining
    a component that logically belongs with other QML components within a file.

    For example, here is a component that is used by multiple \l Loader objects.
    It contains a single item, a \l Rectangle:

    \snippet doc/src/snippets/declarative/component.qml 0

    Notice that while a \l Rectangle by itself would be automatically 
    rendered and displayed, this is not the case for the above rectangle
    because it is defined inside a \c Component. The component encapsulates the
    QML elements within, as if they were defined in a separate QML
    file, and is not loaded until requested (in this case, by the
    two \l Loader objects).

    Defining a \c Component is similar to defining a \l {QML Document}{QML document}.
    A QML document has a single top-level item that defines the behaviors and
    properties of that component, and cannot define properties or behaviors outside
    of that top-level item. In the same way, a \c Component definition contains a single
    top level item (which in the above example is a \l Rectangle) and cannot define any
    data outside of this item, with the exception of an \e id (which in the above example
    is \e redSquare).

    The \c Component element is commonly used to provide graphical components
    for views. For example, the ListView::delegate property requires a \c Component
    to specify how each list item is to be displayed.

    \c Component objects can also be created dynamically using
    \l{QML:Qt::createComponent()}{Qt.createComponent()}.
*/

/*!
    \qmlattachedsignal Component::onCompleted()

    Emitted after component "startup" has completed.  This can be used to
    execute script code at startup, once the full QML environment has been
    established.

    The \c {Component::onCompleted} attached property can be applied to
    any element.  The order of running the \c onCompleted scripts is
    undefined.

    \qml
    Rectangle {
        Component.onCompleted: console.log("Completed Running!")
        Rectangle {
            Component.onCompleted: console.log("Nested Completed Running!")
        }
    }
    \endqml
*/

/*!
    \qmlattachedsignal Component::onDestruction()

    Emitted as the component begins destruction.  This can be used to undo
    work done in the onCompleted signal, or other imperative code in your
    application.

    The \c {Component::onDestruction} attached property can be applied to
    any element.  However, it applies to the destruction of the component as
    a whole, and not the destruction of the specific object.  The order of
    running the \c onDestruction scripts is undefined.

    \qml
    Rectangle {
        Component.onDestruction: console.log("Destruction Beginning!")
        Rectangle {
            Component.onDestruction: console.log("Nested Destruction Beginning!")
        }
    }
    \endqml

    \sa QtDeclarative
*/

/*!
    \enum QDeclarativeComponent::Status
    
    Specifies the loading status of the QDeclarativeComponent.

    \value Null This QDeclarativeComponent has no data.  Call loadUrl() or setData() to add QML content.
    \value Ready This QDeclarativeComponent is ready and create() may be called.
    \value Loading This QDeclarativeComponent is loading network data.
    \value Error An error has occurred.  Call errors() to retrieve a list of \{QDeclarativeError}{errors}.
*/

void QDeclarativeComponentPrivate::typeDataReady(QDeclarativeTypeData *)
{
    Q_Q(QDeclarativeComponent);

    Q_ASSERT(typeData);

    fromTypeData(typeData);
    typeData = 0;

    emit q->statusChanged(q->status());
}

void QDeclarativeComponentPrivate::typeDataProgress(QDeclarativeTypeData *, qreal p)
{
    Q_Q(QDeclarativeComponent);

    progress = p;

    emit q->progressChanged(p);
}

void QDeclarativeComponentPrivate::fromTypeData(QDeclarativeTypeData *data)
{
    url = data->finalUrl();
    QDeclarativeCompiledData *c = data->compiledData();

    if (!c) {
        Q_ASSERT(data->isError());
        state.errors = data->errors();
    } else {
        cc = c;
    }

    data->release();
}

void QDeclarativeComponentPrivate::clear()
{
    if (typeData) {
        typeData->unregisterCallback(this);
        typeData->release();
        typeData = 0;
    }
        
    if (cc) { 
        cc->release();
        cc = 0;
    }
}

/*!
    \internal
*/
QDeclarativeComponent::QDeclarativeComponent(QObject *parent)
    : QObject(*(new QDeclarativeComponentPrivate), parent)
{
}

/*!
    Destruct the QDeclarativeComponent.
*/
QDeclarativeComponent::~QDeclarativeComponent()
{
    Q_D(QDeclarativeComponent);

    if (d->state.completePending) {
        qWarning("QDeclarativeComponent: Component destroyed while completion pending");
        d->completeCreate();
    }

    if (d->typeData) {
        d->typeData->unregisterCallback(d);
        d->typeData->release();
    }
    if (d->cc)
        d->cc->release();
}

/*!
    \qmlproperty enumeration Component::status
    This property holds the status of component loading.  It can be one of:
    \list
    \o Component.Null - no data is available for the component
    \o Component.Ready - the component has been loaded, and can be used to create instances.
    \o Component.Loading - the component is currently being loaded
    \o Component.Error - an error occurred while loading the component.
               Calling errorString() will provide a human-readable description of any errors.
    \endlist
 */

/*!
    \property QDeclarativeComponent::status
    The component's current \l{QDeclarativeComponent::Status} {status}.
 */
QDeclarativeComponent::Status QDeclarativeComponent::status() const
{
    Q_D(const QDeclarativeComponent);

    if (d->typeData)
        return Loading;
    else if (!d->state.errors.isEmpty())
        return Error;
    else if (d->engine && d->cc)
        return Ready;
    else
        return Null;
}

/*!
    Returns true if status() == QDeclarativeComponent::Null.
*/
bool QDeclarativeComponent::isNull() const
{
    return status() == Null;
}

/*!
    Returns true if status() == QDeclarativeComponent::Ready.
*/
bool QDeclarativeComponent::isReady() const
{
    return status() == Ready;
}

/*!
    Returns true if status() == QDeclarativeComponent::Error.
*/
bool QDeclarativeComponent::isError() const
{
    return status() == Error;
}

/*!
    Returns true if status() == QDeclarativeComponent::Loading.
*/
bool QDeclarativeComponent::isLoading() const
{
    return status() == Loading;
}

/*!
    \qmlproperty real Component::progress
    The progress of loading the component, from 0.0 (nothing loaded)
    to 1.0 (finished).
*/

/*!
    \property QDeclarativeComponent::progress
    The progress of loading the component, from 0.0 (nothing loaded)
    to 1.0 (finished).
*/
qreal QDeclarativeComponent::progress() const
{
    Q_D(const QDeclarativeComponent);
    return d->progress;
}

/*!
    \fn void QDeclarativeComponent::progressChanged(qreal progress)

    Emitted whenever the component's loading progress changes.  \a progress will be the
    current progress between 0.0 (nothing loaded) and 1.0 (finished).
*/

/*!
    \fn void QDeclarativeComponent::statusChanged(QDeclarativeComponent::Status status)

    Emitted whenever the component's status changes.  \a status will be the
    new status.
*/

/*!
    Create a QDeclarativeComponent with no data and give it the specified
    \a engine and \a parent. Set the data with setData().
*/
QDeclarativeComponent::QDeclarativeComponent(QDeclarativeEngine *engine, QObject *parent)
    : QObject(*(new QDeclarativeComponentPrivate), parent)
{
    Q_D(QDeclarativeComponent);
    d->engine = engine;
}

/*!
    Create a QDeclarativeComponent from the given \a url and give it the
    specified \a parent and \a engine.

    Ensure that the URL provided is full and correct, in particular, use
    \l QUrl::fromLocalFile() when loading a file from the local filesystem.

    \sa loadUrl()
*/
QDeclarativeComponent::QDeclarativeComponent(QDeclarativeEngine *engine, const QUrl &url, QObject *parent)
: QObject(*(new QDeclarativeComponentPrivate), parent)
{
    Q_D(QDeclarativeComponent);
    d->engine = engine;
    loadUrl(url);
}

/*!
    Create a QDeclarativeComponent from the given \a fileName and give it the specified 
    \a parent and \a engine.

    \sa loadUrl()
*/
QDeclarativeComponent::QDeclarativeComponent(QDeclarativeEngine *engine, const QString &fileName, 
                           QObject *parent)
: QObject(*(new QDeclarativeComponentPrivate), parent)
{
    Q_D(QDeclarativeComponent);
    d->engine = engine;
    loadUrl(d->engine->baseUrl().resolved(QUrl::fromLocalFile(fileName)));
}

/*!
    \internal
*/
QDeclarativeComponent::QDeclarativeComponent(QDeclarativeEngine *engine, QDeclarativeCompiledData *cc, int start, int count, QObject *parent)
    : QObject(*(new QDeclarativeComponentPrivate), parent)
{
    Q_D(QDeclarativeComponent);
    d->engine = engine;
    d->cc = cc;
    cc->addref();
    d->start = start;
    d->count = count;
    d->url = cc->url;
    d->progress = 1.0;
}

/*!
    Sets the QDeclarativeComponent to use the given QML \a data.  If \a url
    is provided, it is used to set the component name and to provide
    a base path for items resolved by this component.
*/
void QDeclarativeComponent::setData(const QByteArray &data, const QUrl &url)
{
    Q_D(QDeclarativeComponent);

    d->clear();

    d->url = url;

    QDeclarativeTypeData *typeData = QDeclarativeEnginePrivate::get(d->engine)->typeLoader.get(data, url);
    
    if (typeData->isCompleteOrError()) {
        d->fromTypeData(typeData);
    } else {
        d->typeData = typeData;
        d->typeData->registerCallback(d);
    }

    d->progress = 1.0;
    emit statusChanged(status());
    emit progressChanged(d->progress);
}

/*!
Returns the QDeclarativeContext the component was created in.  This is only
valid for components created directly from QML.
*/
QDeclarativeContext *QDeclarativeComponent::creationContext() const
{
    Q_D(const QDeclarativeComponent);
    if(d->creationContext)
        return d->creationContext->asQDeclarativeContext();

    return qmlContext(this);
}

/*!
    Load the QDeclarativeComponent from the provided \a url.

    Ensure that the URL provided is full and correct, in particular, use
    \l QUrl::fromLocalFile() when loading a file from the local filesystem.
*/
void QDeclarativeComponent::loadUrl(const QUrl &url)
{
    Q_D(QDeclarativeComponent);

    d->clear();

    if ((url.isRelative() && !url.isEmpty())
    || url.scheme() == QLatin1String("file")) // Workaround QTBUG-11929
        d->url = d->engine->baseUrl().resolved(url);
    else
        d->url = url;

    if (url.isEmpty()) {
        QDeclarativeError error;
        error.setDescription(tr("Invalid empty URL"));
        d->state.errors << error;
        return;
    }

    QDeclarativeTypeData *data = QDeclarativeEnginePrivate::get(d->engine)->typeLoader.get(d->url);

    if (data->isCompleteOrError()) {
        d->fromTypeData(data);
        d->progress = 1.0;
    } else {
        d->typeData = data;
        d->typeData->registerCallback(d);
        d->progress = data->progress();
    }

    emit statusChanged(status());
    emit progressChanged(d->progress);
}

/*!
    Return the list of errors that occurred during the last compile or create
    operation.  An empty list is returned if isError() is not set.
*/
QList<QDeclarativeError> QDeclarativeComponent::errors() const
{
    Q_D(const QDeclarativeComponent);
    if (isError())
        return d->state.errors;
    else
        return QList<QDeclarativeError>();
}

/*!
    \qmlmethod string Component::errorString()

    Returns a human-readable description of any errors.

    The string includes the file, location, and description of each error.
    If multiple errors are present they are separated by a newline character.

    If no errors are present, an empty string is returned.
*/

/*!
    \internal
    errorString is only meant as a way to get the errors in script
*/
QString QDeclarativeComponent::errorString() const
{
    Q_D(const QDeclarativeComponent);
    QString ret;
    if(!isError())
        return ret;
    foreach(const QDeclarativeError &e, d->state.errors) {
        ret += e.url().toString() + QLatin1Char(':') +
               QString::number(e.line()) + QLatin1Char(' ') +
               e.description() + QLatin1Char('\n');
    }
    return ret;
}

/*!
    \qmlproperty url Component::url
    The component URL.  This is the URL that was used to construct the component.
*/

/*!
    \property QDeclarativeComponent::url
    The component URL.  This is the URL passed to either the constructor,
    or the loadUrl() or setData() methods.
*/
QUrl QDeclarativeComponent::url() const
{
    Q_D(const QDeclarativeComponent);
    return d->url;
}

/*!
    \internal
*/
QDeclarativeComponent::QDeclarativeComponent(QDeclarativeComponentPrivate &dd, QObject *parent)
    : QObject(dd, parent)
{
}

/*!
    \qmlmethod object Component::createObject(Item parent, object properties)

    Creates and returns an object instance of this component that will have
    the given \a parent and \a properties. The \a properties argument is optional.
    Returns null if object creation fails.

    The object will be created in the same context as the one in which the component
    was created. This function will always return null when called on components
    which were not created in QML.

    If you wish to create an object without setting a parent, specify \c null for
    the \a parent value. Note that if the returned object is to be displayed, you 
    must provide a valid \a parent value or set the returned object's \l{Item::parent}{parent} 
    property, or else the object will not be visible.

    If a \a parent is not provided to createObject(), a reference to the returned object must be held so that
    it is not destroyed by the garbage collector.  This is true regardless of whether \l{Item::parent} is set afterwards,
    since setting the Item parent does not change object ownership; only the graphical parent is changed.

    As of QtQuick 1.1, this method accepts an optional \a properties argument that specifies a
    map of initial property values for the created object. These values are applied before object
    creation is finalized. (This is more efficient than setting property values after object creation,
    particularly where large sets of property values are defined, and also allows property bindings
    to be set up before the object is created.)

    The \a properties argument is specified as a map of property-value items. For example, the code
    below creates an object with initial \c x and \c y values of 100 and 200, respectively:

    \qml
        var component = Qt.createComponent("Button.qml");
        if (component.status == Component.Ready)
            component.createObject(parent, {"x": 100, "y": 100});
    \endqml

    Dynamically created instances can be deleted with the \c destroy() method.
    See \l {Dynamic Object Management in QML} for more information.
*/

/*!
    \internal
    A version of create which returns a scriptObject, for use in script.
    This function will only work on components created in QML.

    Sets graphics object parent because forgetting to do this is a frequent
    and serious problem.
*/
QScriptValue QDeclarativeComponent::createObject(QObject* parent)
{
    Q_D(QDeclarativeComponent);
    return d->createObject(parent, QScriptValue(QScriptValue::NullValue));
}

/*!
    \internal
    Overloadable method allows properties to be set during creation
*/
QScriptValue QDeclarativeComponent::createObject(QObject* parent, const QScriptValue& valuemap)
{
    Q_D(QDeclarativeComponent);

    if (!valuemap.isObject() || valuemap.isArray()) {
        qmlInfo(this) << tr("createObject: value is not an object");
        return QScriptValue(QScriptValue::NullValue);
    }
    return d->createObject(parent, valuemap);
}

QScriptValue QDeclarativeComponentPrivate::createObject(QObject *publicParent, const QScriptValue valuemap)
{
    Q_Q(QDeclarativeComponent);
    QDeclarativeContext* ctxt = q->creationContext();
    if(!ctxt && engine)
        ctxt = engine->rootContext();
    if (!ctxt)
        return QScriptValue(QScriptValue::NullValue);
    QObject* ret = q->beginCreate(ctxt);
    if (!ret) {
        q->completeCreate();
        return QScriptValue(QScriptValue::NullValue);
    }

    if (publicParent) {
        ret->setParent(publicParent);
        QList<QDeclarativePrivate::AutoParentFunction> functions = QDeclarativeMetaType::parentFunctions();

        bool needParent = false;

        for (int ii = 0; ii < functions.count(); ++ii) {
            QDeclarativePrivate::AutoParentResult res = functions.at(ii)(ret, publicParent);
            if (res == QDeclarativePrivate::Parented) {
                needParent = false;
                break;
            } else if (res == QDeclarativePrivate::IncompatibleParent) {
                needParent = true;
            }
        }

        if (needParent)
            qWarning("QDeclarativeComponent: Created graphical object was not placed in the graphics scene.");
    }

    QDeclarativeEnginePrivate *priv = QDeclarativeEnginePrivate::get(engine);
    QDeclarativeData::get(ret, true)->setImplicitDestructible();
    QScriptValue newObject = priv->objectClass->newQObject(ret, QMetaType::QObjectStar);

    if (valuemap.isObject() && !valuemap.isArray()) {
        //Iterate through and assign properties
        QScriptValueIterator it(valuemap);
        while (it.hasNext()) {
            it.next();
            QScriptValue prop = newObject;
            QString propName = it.name();
            int index = propName.indexOf(QLatin1Char('.'));
            if (index > 0) {
                QString subProp = propName;
                int lastIndex = 0;
                while (index > 0) {
                    subProp = propName.mid(lastIndex, index - lastIndex);
                    prop = prop.property(subProp);
                    lastIndex = index + 1;
                    index = propName.indexOf(QLatin1Char('.'), index + 1);
                }
                prop.setProperty(propName.mid(propName.lastIndexOf(QLatin1Char('.')) + 1), it.value());
            } else {
                newObject.setProperty(propName, it.value());
            }
        }
    }

    q->completeCreate();

    return newObject;
}

/*!
    Create an object instance from this component.  Returns 0 if creation
    failed.  \a context specifies the context within which to create the object
    instance.  

    If \a context is 0 (the default), it will create the instance in the
    engine' s \l {QDeclarativeEngine::rootContext()}{root context}.
*/
QObject *QDeclarativeComponent::create(QDeclarativeContext *context)
{
    Q_D(QDeclarativeComponent);

    if (!context)
        context = d->engine->rootContext();

    QObject *rv = beginCreate(context);
    completeCreate();
    return rv;
}

/*!
    This method provides more advanced control over component instance creation.
    In general, programmers should use QDeclarativeComponent::create() to create a 
    component.

    Create an object instance from this component.  Returns 0 if creation
    failed.  \a context specifies the context within which to create the object
    instance.  

    When QDeclarativeComponent constructs an instance, it occurs in three steps:
    \list 1
    \i The object hierarchy is created, and constant values are assigned.
    \i Property bindings are evaluated for the the first time.
    \i If applicable, QDeclarativeParserStatus::componentComplete() is called on objects.
    \endlist 
    QDeclarativeComponent::beginCreate() differs from QDeclarativeComponent::create() in that it
    only performs step 1.  QDeclarativeComponent::completeCreate() must be called to 
    complete steps 2 and 3.

    This breaking point is sometimes useful when using attached properties to
    communicate information to an instantiated component, as it allows their
    initial values to be configured before property bindings take effect.
*/
QObject *QDeclarativeComponent::beginCreate(QDeclarativeContext *context)
{
    Q_D(QDeclarativeComponent);
    QObject *rv = d->beginCreate(context?QDeclarativeContextData::get(context):0, QBitField());
    if (rv) {
        QDeclarativeData *ddata = QDeclarativeData::get(rv);
        Q_ASSERT(ddata);
        ddata->indestructible = true;
    }
    return rv;
}

QObject *
QDeclarativeComponentPrivate::beginCreate(QDeclarativeContextData *context, const QBitField &bindings)
{
    Q_Q(QDeclarativeComponent);
    if (!context) {
        qWarning("QDeclarativeComponent: Cannot create a component in a null context");
        return 0;
    }

    if (!context->isValid()) {
        qWarning("QDeclarativeComponent: Cannot create a component in an invalid context");
        return 0;
    }

    if (context->engine != engine) {
        qWarning("QDeclarativeComponent: Must create component in context from the same QDeclarativeEngine");
        return 0;
    }

    if (state.completePending) {
        qWarning("QDeclarativeComponent: Cannot create new component instance before completing the previous");
        return 0;
    }

    if (!q->isReady()) {
        qWarning("QDeclarativeComponent: Component is not ready");
        return 0;
    }

    return begin(context, creationContext, cc, start, count, &state, 0, bindings);
}

QObject * QDeclarativeComponentPrivate::begin(QDeclarativeContextData *parentContext, 
                                              QDeclarativeContextData *componentCreationContext,
                                              QDeclarativeCompiledData *component, int start, int count,
                                              ConstructionState *state, QList<QDeclarativeError> *errors,
                                              const QBitField &bindings)
{
    QDeclarativeEnginePrivate *enginePriv = QDeclarativeEnginePrivate::get(parentContext->engine);
    bool isRoot = !enginePriv->inBeginCreate;

    Q_ASSERT(!isRoot || state); // Either this isn't a root component, or a state data must be provided
    Q_ASSERT((state != 0) ^ (errors != 0)); // One of state or errors (but not both) must be provided

    if (isRoot) {
        QDeclarativeDebugTrace::startRange(QDeclarativeDebugTrace::Creating);
        QDeclarativeDebugTrace::rangeData(QDeclarativeDebugTrace::Creating, component->url);
    }

    QDeclarativeContextData *ctxt = new QDeclarativeContextData;
    ctxt->isInternal = true;
    ctxt->url = component->url;
    ctxt->imports = component->importCache;

    // Nested global imports
    if (componentCreationContext && start != -1) 
        ctxt->importedScripts = componentCreationContext->importedScripts;

    component->importCache->addref();
    ctxt->setParent(parentContext);

    enginePriv->inBeginCreate = true;

    QDeclarativeVME vme;
    QObject *rv = vme.run(ctxt, component, start, count, bindings);

    if (vme.isError()) {
       if(errors) *errors = vme.errors();
       else state->errors = vme.errors();
    }

    if (isRoot) {
        enginePriv->inBeginCreate = false;

        state->bindValues = enginePriv->bindValues;
        state->parserStatus = enginePriv->parserStatus;
        state->componentAttached = enginePriv->componentAttached;
        if (state->componentAttached)
            state->componentAttached->prev = &state->componentAttached;

        enginePriv->componentAttached = 0;
        enginePriv->bindValues.clear();
        enginePriv->parserStatus.clear();
        state->completePending = true;
        enginePriv->inProgressCreations++;
    }

    if (enginePriv->isDebugging && rv) {
        if  (!parentContext->isInternal)
            parentContext->asQDeclarativeContextPrivate()->instances.append(rv);
        QDeclarativeEngineDebugServer::instance()->objectCreated(parentContext->engine, rv);
    }

    return rv;
}

void QDeclarativeComponentPrivate::beginDeferred(QDeclarativeEnginePrivate *enginePriv,
                                                 QObject *object, ConstructionState *state)
{
    bool isRoot = !enginePriv->inBeginCreate;
    enginePriv->inBeginCreate = true;

    QDeclarativeVME vme;
    vme.runDeferred(object);

    if (vme.isError()) 
        state->errors = vme.errors();

    if (isRoot) {
        enginePriv->inBeginCreate = false;

        state->bindValues = enginePriv->bindValues;
        state->parserStatus = enginePriv->parserStatus;
        state->componentAttached = enginePriv->componentAttached;
        if (state->componentAttached)
            state->componentAttached->prev = &state->componentAttached;

        enginePriv->componentAttached = 0;
        enginePriv->bindValues.clear();
        enginePriv->parserStatus.clear();
        state->completePending = true;
        enginePriv->inProgressCreations++;
    }
}

void QDeclarativeComponentPrivate::complete(QDeclarativeEnginePrivate *enginePriv, ConstructionState *state)
{
    if (state->completePending) {

        for (int ii = 0; ii < state->bindValues.count(); ++ii) {
            QDeclarativeEnginePrivate::SimpleList<QDeclarativeAbstractBinding> bv = 
                state->bindValues.at(ii);
            for (int jj = 0; jj < bv.count; ++jj) {
                if(bv.at(jj)) {
                    // XXX akennedy
                    bv.at(jj)->m_mePtr = 0;
                    bv.at(jj)->setEnabled(true, QDeclarativePropertyPrivate::BypassInterceptor | 
                                                QDeclarativePropertyPrivate::DontRemoveBinding);
                }
            }
            QDeclarativeEnginePrivate::clear(bv);
        }

        for (int ii = 0; ii < state->parserStatus.count(); ++ii) {
            QDeclarativeEnginePrivate::SimpleList<QDeclarativeParserStatus> ps = 
                state->parserStatus.at(ii);

            for (int jj = ps.count - 1; jj >= 0; --jj) {
                QDeclarativeParserStatus *status = ps.at(jj);
                if (status && status->d) {
                    status->d = 0;
                    status->componentComplete();
                }
            }
            QDeclarativeEnginePrivate::clear(ps);
        }

        if (1 == enginePriv->inProgressCreations) {
            for (int ii = 0; ii < enginePriv->finalizedParserStatus.count(); ++ii) {
                QPair<QDeclarativeGuard<QObject>, int> status = enginePriv->finalizedParserStatus.at(ii);
                QObject *obj = status.first;
                if (obj) {
                    void *args[] = { 0 };
                    QMetaObject::metacall(obj, QMetaObject::InvokeMetaMethod,
                                          status.second, args);
                }
            }
            enginePriv->finalizedParserStatus.clear();
        }

        while (state->componentAttached) {
            QDeclarativeComponentAttached *a = state->componentAttached;
            a->rem();
            QDeclarativeData *d = QDeclarativeData::get(a->parent());
            Q_ASSERT(d);
            Q_ASSERT(d->context);
            a->add(&d->context->componentAttached);
            emit a->completed();
        }

        state->bindValues.clear();
        state->parserStatus.clear();
        state->completePending = false;

        enginePriv->inProgressCreations--;
        if (0 == enginePriv->inProgressCreations) {
            while (enginePriv->erroredBindings) {
                enginePriv->warning(enginePriv->erroredBindings->error);
                enginePriv->erroredBindings->removeError();
            }
        }
    }
}

/*!
    This method provides more advanced control over component instance creation.
    In general, programmers should use QDeclarativeComponent::create() to create a 
    component.

    Complete a component creation begin with QDeclarativeComponent::beginCreate().
*/
void QDeclarativeComponent::completeCreate()
{
    Q_D(QDeclarativeComponent);
    d->completeCreate();
}

void QDeclarativeComponentPrivate::completeCreate()
{
    if (state.completePending) {
        QDeclarativeEnginePrivate *ep = QDeclarativeEnginePrivate::get(engine);
        complete(ep, &state);

        QDeclarativeDebugTrace::endRange(QDeclarativeDebugTrace::Creating);
    }
}

QDeclarativeComponentAttached::QDeclarativeComponentAttached(QObject *parent)
: QObject(parent), prev(0), next(0)
{
}

QDeclarativeComponentAttached::~QDeclarativeComponentAttached()
{
    if (prev) *prev = next;
    if (next) next->prev = prev;
    prev = 0;
    next = 0;
}

/*!
    \internal
*/
QDeclarativeComponentAttached *QDeclarativeComponent::qmlAttachedProperties(QObject *obj)
{
    QDeclarativeComponentAttached *a = new QDeclarativeComponentAttached(obj);

    QDeclarativeEngine *engine = qmlEngine(obj);
    if (!engine)
        return a;

    if (QDeclarativeEnginePrivate::get(engine)->inBeginCreate) {
        QDeclarativeEnginePrivate *p = QDeclarativeEnginePrivate::get(engine);
        a->add(&p->componentAttached);
    } else {
        QDeclarativeData *d = QDeclarativeData::get(obj);
        Q_ASSERT(d);
        Q_ASSERT(d->context);
        a->add(&d->context->componentAttached);
    }

    return a;
}

QT_END_NAMESPACE