summaryrefslogtreecommitdiffstats
path: root/src/script/api/qscriptcontext.cpp
blob: 3f08e749dff78c8f394f1765e216bbe7b91aa215 (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
/****************************************************************************
**
** 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 QtScript module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL-ONLY$
** GNU Lesser General Public License Usage
** 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.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/

#include "config.h"
#include "qscriptcontext.h"

#include "qscriptcontext_p.h"
#include "qscriptcontextinfo.h"
#include "qscriptengine.h"
#include "qscriptengine_p.h"
#include "../bridge/qscriptactivationobject_p.h"

#include "Arguments.h"
#include "CodeBlock.h"
#include "Error.h"
#include "JSFunction.h"
#include "JSObject.h"
#include "JSGlobalObject.h"

#include <QtCore/qstringlist.h>

QT_BEGIN_NAMESPACE

/*!
  \since 4.3
  \class QScriptContext

  \brief The QScriptContext class represents a Qt Script function invocation.

  \ingroup script
  \mainclass

  A QScriptContext provides access to the `this' object and arguments
  passed to a script function. You typically want to access this
  information when you're writing a native (C++) function (see
  QScriptEngine::newFunction()) that will be called from script
  code. For example, when the script code

  \snippet doc/src/snippets/code/src_script_qscriptcontext.cpp 0

  is evaluated, a QScriptContext will be created, and the context will
  carry the arguments as QScriptValues; in this particular case, the
  arguments will be one QScriptValue containing the number 20.5, a second
  QScriptValue containing the string \c{"hello"}, and a third QScriptValue
  containing a Qt Script object.

  Use argumentCount() to get the number of arguments passed to the
  function, and argument() to get an argument at a certain index. The
  argumentsObject() function returns a Qt Script array object
  containing all the arguments; you can use the QScriptValueIterator
  to iterate over its elements, or pass the array on as arguments to
  another script function using QScriptValue::call().

  Use thisObject() to get the `this' object associated with the function call,
  and setThisObject() to set the `this' object. If you are implementing a
  native "instance method", you typically fetch the thisObject() and access
  one or more of its properties:

  \snippet doc/src/snippets/code/src_script_qscriptcontext.cpp 1

  Use isCalledAsConstructor() to determine if the function was called
  as a constructor (e.g. \c{"new foo()"} (as constructor) or just
  \c{"foo()"}).  When a function is called as a constructor, the
  thisObject() contains the newly constructed object that the function
  is expected to initialize.

  Use throwValue() or throwError() to throw an exception.

  Use callee() to obtain the QScriptValue that represents the function being
  called. This can for example be used to call the function recursively.

  Use parentContext() to get a pointer to the context that precedes
  this context in the activation stack. This is mostly useful for
  debugging purposes (e.g. when constructing some form of backtrace).

  The activationObject() function returns the object that is used to
  hold the local variables associated with this function call. You can
  replace the activation object by calling setActivationObject(). A
  typical usage of these functions is when you want script code to be
  evaluated in the context of the parent context, e.g. to implement an
  include() function:

  \snippet doc/src/snippets/code/src_script_qscriptcontext.cpp 2

  Use backtrace() to get a human-readable backtrace associated with
  this context. This can be useful for debugging purposes when
  implementing native functions. The toString() function provides a
  string representation of the context. (QScriptContextInfo provides
  more detailed debugging-related information about the
  QScriptContext.)

  Use engine() to obtain a pointer to the QScriptEngine that this context
  resides in.

  \sa QScriptContextInfo, QScriptEngine::newFunction(), QScriptable
*/

/*!
    \enum QScriptContext::ExecutionState

    This enum specifies the frameution state of the context.

    \value NormalState The context is in a normal state.

    \value ExceptionState The context is in an exceptional state.
*/

/*!
    \enum QScriptContext::Error

    This enum specifies types of error.

    \value ReferenceError A reference error.

    \value SyntaxError A syntax error.

    \value TypeError A type error.

    \value RangeError A range error.

    \value URIError A URI error.

    \value UnknownError An unknown error.
*/

/*!
  \internal
*/
QScriptContext::QScriptContext()
{
    //QScriptContext doesn't exist,  pointer to QScriptContext are just pointer to  JSC::CallFrame
    Q_ASSERT(false);
}

/*!
  Throws an exception with the given \a value.
  Returns the value thrown (the same as the argument).

  \sa throwError(), state()
*/
QScriptValue QScriptContext::throwValue(const QScriptValue &value)
{
    JSC::CallFrame *frame = QScriptEnginePrivate::frameForContext(this);
    QScript::APIShim shim(QScript::scriptEngineFromExec(frame));
    JSC::JSValue jscValue = QScript::scriptEngineFromExec(frame)->scriptValueToJSCValue(value);
    frame->setException(jscValue);
    return value;
}

/*!
  Throws an \a error with the given \a text.
  Returns the created error object.

  The \a text will be stored in the \c{message} property of the error
  object.

  The error object will be initialized to contain information about
  the location where the error occurred; specifically, it will have
  properties \c{lineNumber}, \c{fileName} and \c{stack}. These
  properties are described in \l {QtScript Extensions to ECMAScript}.

  \sa throwValue(), state()
*/
QScriptValue QScriptContext::throwError(Error error, const QString &text)
{
    JSC::CallFrame *frame = QScriptEnginePrivate::frameForContext(this);
    QScript::APIShim shim(QScript::scriptEngineFromExec(frame));
    JSC::ErrorType jscError = JSC::GeneralError;
    switch (error) {
    case UnknownError:
        break;
    case ReferenceError:
        jscError = JSC::ReferenceError;
        break;
    case SyntaxError:
        jscError = JSC::SyntaxError;
        break;
    case TypeError:
        jscError = JSC::TypeError;
        break;
    case RangeError:
        jscError = JSC::RangeError;
        break;
    case URIError:
        jscError = JSC::URIError;
        break;
    }
    JSC::JSObject *result = JSC::throwError(frame, jscError, text);
    return QScript::scriptEngineFromExec(frame)->scriptValueFromJSCValue(result);
}

/*!
  \overload

  Throws an error with the given \a text.
  Returns the created error object.

  \sa throwValue(), state()
*/
QScriptValue QScriptContext::throwError(const QString &text)
{
    JSC::CallFrame *frame = QScriptEnginePrivate::frameForContext(this);
    QScript::APIShim shim(QScript::scriptEngineFromExec(frame));
    JSC::JSObject *result = JSC::throwError(frame, JSC::GeneralError, text);
    return QScript::scriptEngineFromExec(frame)->scriptValueFromJSCValue(result);
}

/*!
  Destroys this QScriptContext.
*/
QScriptContext::~QScriptContext()
{
    //QScriptContext doesn't exist,  pointer to QScriptContext are just pointer to JSC::CallFrame
    Q_ASSERT(false);
}

/*!
  Returns the QScriptEngine that this QScriptContext belongs to.
*/
QScriptEngine *QScriptContext::engine() const
{
    const JSC::CallFrame *frame = QScriptEnginePrivate::frameForContext(this);
    return QScriptEnginePrivate::get(QScript::scriptEngineFromExec(frame));
}

/*!
  Returns the function argument at the given \a index.

  If \a index >= argumentCount(), a QScriptValue of
  the primitive type Undefined is returned.

  \sa argumentCount()
*/
QScriptValue QScriptContext::argument(int index) const
{
    if (index < 0)
        return QScriptValue();
    if (index >= argumentCount())
        return QScriptValue(QScriptValue::UndefinedValue);
    QScriptValue v = argumentsObject().property(index);
    return v;
}

/*!
  Returns the callee. The callee is the function object that this
  QScriptContext represents an invocation of.
*/
QScriptValue QScriptContext::callee() const
{
    const JSC::CallFrame *frame = QScriptEnginePrivate::frameForContext(this);
    QScript::APIShim shim(QScript::scriptEngineFromExec(frame));
    return QScript::scriptEngineFromExec(frame)->scriptValueFromJSCValue(frame->callee());
}

/*!
  Returns the arguments object of this QScriptContext.

  The arguments object has properties \c callee (equal to callee())
  and \c length (equal to argumentCount()), and properties \c 0, \c 1,
  ..., argumentCount() - 1 that provide access to the argument
  values. Initially, property \c P (0 <= \c P < argumentCount()) has
  the same value as argument(\c P). In the case when \c P is less
  than the number of formal parameters of the function, \c P shares
  its value with the corresponding property of the activation object
  (activationObject()). This means that changing this property changes
  the corresponding property of the activation object and vice versa.

  \sa argument(), activationObject()
*/
QScriptValue QScriptContext::argumentsObject() const
{
    JSC::CallFrame *frame = const_cast<JSC::ExecState*>(QScriptEnginePrivate::frameForContext(this));
    QScript::APIShim shim(QScript::scriptEngineFromExec(frame));

    if (frame == frame->lexicalGlobalObject()->globalExec()) {
        // <global> context doesn't have arguments. return an empty object
        return QScriptEnginePrivate::get(QScript::scriptEngineFromExec(frame))->newObject();
    }

    //for a js function
    if (frame->codeBlock() && frame->callee()) {
        JSC::JSValue result = frame->interpreter()->retrieveArguments(frame, JSC::asFunction(frame->callee()));
        return QScript::scriptEngineFromExec(frame)->scriptValueFromJSCValue(result);
    }

    if (frame->callerFrame()->hasHostCallFrameFlag()) {
        // <eval> context doesn't have arguments. return an empty object
        return QScriptEnginePrivate::get(QScript::scriptEngineFromExec(frame))->newObject();
    }

    //for a native function
    if (!frame->optionalCalleeArguments()) {
        Q_ASSERT(frame->argumentCount() > 0); //we need at least 'this' otherwise we'll crash later
        JSC::Arguments* arguments = new (&frame->globalData())JSC::Arguments(frame, JSC::Arguments::NoParameters);
        frame->setCalleeArguments(arguments);
    }
    return QScript::scriptEngineFromExec(frame)->scriptValueFromJSCValue(frame->optionalCalleeArguments());
}

/*!
  Returns true if the function was called as a constructor
  (e.g. \c{"new foo()"}); otherwise returns false.

  When a function is called as constructor, the thisObject()
  contains the newly constructed object to be initialized.
*/
bool QScriptContext::isCalledAsConstructor() const
{
    JSC::CallFrame *frame = const_cast<JSC::ExecState*>(QScriptEnginePrivate::frameForContext(this));
    QScript::APIShim shim(QScript::scriptEngineFromExec(frame));

    //For native functions, look up flags.
    uint flags = QScriptEnginePrivate::contextFlags(frame);
    if (flags & QScriptEnginePrivate::NativeContext)
        return flags & QScriptEnginePrivate::CalledAsConstructorContext;

    //Not a native function, try to look up in the bytecode if we where called from op_construct
    JSC::Instruction* returnPC = frame->returnPC();

    if (!returnPC)
        return false;

    JSC::CallFrame *callerFrame = QScriptEnginePrivate::frameForContext(parentContext());
    if (!callerFrame)
        return false;

    if (returnPC[-JSC::op_construct_length].u.opcode == frame->interpreter()->getOpcode(JSC::op_construct)) {
        //We are maybe called from the op_construct opcode which has 6 opperands.
        //But we need to check we are not called from op_call with 4 opperands

        //we make sure that the returnPC[-1] (thisRegister) is smaller than the returnPC[-3] (registerOffset)
        //as if it was an op_call, the returnPC[-1] would be the registerOffset, bigger than returnPC[-3] (funcRegister)
        return returnPC[-1].u.operand < returnPC[-3].u.operand;
    }
    return false;
}

/*!
  Returns the parent context of this QScriptContext.
*/
QScriptContext *QScriptContext::parentContext() const
{
    const JSC::CallFrame *frame = QScriptEnginePrivate::frameForContext(this);
    QScript::APIShim shim(QScript::scriptEngineFromExec(frame));
    JSC::CallFrame *callerFrame = frame->callerFrame()->removeHostCallFrameFlag();
    return QScriptEnginePrivate::contextForFrame(callerFrame);
}

/*!
  Returns the number of arguments passed to the function
  in this invocation.

  Note that the argument count can be different from the
  formal number of arguments (the \c{length} property of
  callee()).

  \sa argument()
*/
int QScriptContext::argumentCount() const
{
    const JSC::CallFrame *frame = QScriptEnginePrivate::frameForContext(this);
    int argc = frame->argumentCount();
    if (argc != 0)
        --argc; // -1 due to "this"
    return argc;
}

/*!
  \internal
*/
QScriptValue QScriptContext::returnValue() const
{
    qWarning("QScriptContext::returnValue() not implemented");
    return QScriptValue();
}

/*!
  \internal
*/
void QScriptContext::setReturnValue(const QScriptValue &result)
{
    JSC::CallFrame *frame = QScriptEnginePrivate::frameForContext(this);
    JSC::CallFrame *callerFrame = frame->callerFrame();
    if (!callerFrame->codeBlock())
        return;
    Q_ASSERT_X(false, Q_FUNC_INFO, "check me");
    int dst = frame->registers()[JSC::RegisterFile::ReturnValueRegister].i(); // returnValueRegister() is private
    callerFrame[dst] = QScript::scriptEngineFromExec(frame)->scriptValueToJSCValue(result);
}

/*!
  Returns the activation object of this QScriptContext. The activation
  object provides access to the local variables associated with this
  context.

  \sa argument(), argumentsObject()
*/

QScriptValue QScriptContext::activationObject() const
{
    JSC::CallFrame *frame = const_cast<JSC::ExecState*>(QScriptEnginePrivate::frameForContext(this));
    QScript::APIShim shim(QScript::scriptEngineFromExec(frame));
    JSC::JSObject *result = 0;

    uint flags = QScriptEnginePrivate::contextFlags(frame);
    if ((flags & QScriptEnginePrivate::NativeContext) && !(flags & QScriptEnginePrivate::HasScopeContext)) {
        //For native functions, lazily create it if needed
        QScript::QScriptActivationObject *scope = new (frame) QScript::QScriptActivationObject(frame);
        frame->setScopeChain(frame->scopeChain()->copy()->push(scope));
        result = scope;
        QScriptEnginePrivate::setContextFlags(frame, flags | QScriptEnginePrivate::HasScopeContext);
    } else {
        // look in scope chain
        JSC::ScopeChainNode *node = frame->scopeChain();
        JSC::ScopeChainIterator it(node);
        for (it = node->begin(); it != node->end(); ++it) {
            if ((*it) && (*it)->isVariableObject()) {
                result = *it;
                break;
            }
        }
    }
    if (!result) {
        if (!parentContext())
            return engine()->globalObject();

        qWarning("QScriptContext::activationObject:  could not get activation object for frame");
        return QScriptValue();
        /*JSC::CodeBlock *codeBlock = frame->codeBlock();
        if (!codeBlock) {
            // non-Qt native function 
            Q_ASSERT(true); //### this should in theorry not happen
            result = new (frame)QScript::QScriptActivationObject(frame);
        } else {
            // ### this is wrong
            JSC::FunctionBodyNode *body = static_cast<JSC::FunctionBodyNode*>(codeBlock->ownerNode());
            result = new (frame)JSC::JSActivation(frame, body);
        }*/
    }

    if (result && result->inherits(&QScript::QScriptActivationObject::info)
        && (static_cast<QScript::QScriptActivationObject*>(result)->delegate() != 0)) {
        // Return the object that property access is being delegated to
        result = static_cast<QScript::QScriptActivationObject*>(result)->delegate();
    }

    return QScript::scriptEngineFromExec(frame)->scriptValueFromJSCValue(result);
}

/*!
  Sets the activation object of this QScriptContext to be the given \a
  activation.

  If \a activation is not an object, this function does nothing.
*/
void QScriptContext::setActivationObject(const QScriptValue &activation)
{
    if (!activation.isObject())
        return;
    else if (activation.engine() != engine()) {
        qWarning("QScriptContext::setActivationObject() failed: "
                 "cannot set an object created in "
                 "a different engine");
        return;
    }
    JSC::CallFrame *frame = QScriptEnginePrivate::frameForContext(this);
    QScriptEnginePrivate *engine = QScript::scriptEngineFromExec(frame);
    QScript::APIShim shim(engine);
    JSC::JSObject *object = JSC::asObject(engine->scriptValueToJSCValue(activation));
    if (object == engine->originalGlobalObjectProxy)
        object = engine->originalGlobalObject();

    uint flags = QScriptEnginePrivate::contextFlags(frame);
    if ((flags & QScriptEnginePrivate::NativeContext) && !(flags & QScriptEnginePrivate::HasScopeContext)) {
        //For native functions, we create a scope node
        JSC::JSObject *scope = object;
        if (!scope->isVariableObject()) {
            // Create a QScriptActivationObject that acts as a proxy
            scope = new (frame) QScript::QScriptActivationObject(frame, scope);
        }
        frame->setScopeChain(frame->scopeChain()->copy()->push(scope));
        QScriptEnginePrivate::setContextFlags(frame, flags | QScriptEnginePrivate::HasScopeContext);
        return;
    }

    // else replace the first activation object in the scope chain
    JSC::ScopeChainNode *node = frame->scopeChain();
    while (node != 0) {
        if (node->object && node->object->isVariableObject()) {
            if (!object->isVariableObject()) {
                if (node->object->inherits(&QScript::QScriptActivationObject::info)) {
                    static_cast<QScript::QScriptActivationObject*>(node->object)->setDelegate(object);
                } else {
                    // Create a QScriptActivationObject that acts as a proxy
                    node->object = new (frame) QScript::QScriptActivationObject(frame, object);
                }
            } else {
                node->object = object;
            }
            break;
        }
        node = node->next;
    }
}

/*!
  Returns the `this' object associated with this QScriptContext.
*/
QScriptValue QScriptContext::thisObject() const
{
    JSC::CallFrame *frame = const_cast<JSC::ExecState*>(QScriptEnginePrivate::frameForContext(this));
    QScriptEnginePrivate *engine = QScript::scriptEngineFromExec(frame);
    QScript::APIShim shim(engine);
    JSC::JSValue result = engine->thisForContext(frame);
    if (!result || result.isNull())
        result = frame->globalThisValue();
    return engine->scriptValueFromJSCValue(result);
}

/*!
  Sets the `this' object associated with this QScriptContext to be
  \a thisObject.

  If \a thisObject is not an object, this function does nothing.
*/
void QScriptContext::setThisObject(const QScriptValue &thisObject)
{
    JSC::CallFrame *frame = QScriptEnginePrivate::frameForContext(this);
    QScript::APIShim shim(QScript::scriptEngineFromExec(frame));
    if (!thisObject.isObject())
        return;
    if (thisObject.engine() != engine()) {
        qWarning("QScriptContext::setThisObject() failed: "
                 "cannot set an object created in "
                 "a different engine");
        return;
    }
    if (frame == frame->lexicalGlobalObject()->globalExec()) {
        engine()->setGlobalObject(thisObject);
        return;
    }
    JSC::JSValue jscThisObject = QScript::scriptEngineFromExec(frame)->scriptValueToJSCValue(thisObject);
    JSC::CodeBlock *cb = frame->codeBlock();
    if (cb != 0) {
        frame[cb->thisRegister()] = jscThisObject;
    } else {
        JSC::Register* thisRegister = QScriptEnginePrivate::thisRegisterForFrame(frame);
        thisRegister[0] = jscThisObject;
    }
}

/*!
  Returns the frameution state of this QScriptContext.
*/
QScriptContext::ExecutionState QScriptContext::state() const
{
    const JSC::CallFrame *frame = QScriptEnginePrivate::frameForContext(this);
    if (frame->hadException())
        return QScriptContext::ExceptionState;
    return QScriptContext::NormalState;
}

/*!
  Returns a human-readable backtrace of this QScriptContext.

  Each line is of the form \c{<function-name>(<arguments>)@<file-name>:<line-number>}.

  To access individual pieces of debugging-related information (for
  example, to construct your own backtrace representation), use
  QScriptContextInfo.

  \sa QScriptEngine::uncaughtExceptionBacktrace(), QScriptContextInfo, toString()
*/
QStringList QScriptContext::backtrace() const
{
    QStringList result;
    const QScriptContext *ctx = this;
    while (ctx) {
        result.append(ctx->toString());
        ctx = ctx->parentContext();
    }
    return result;
}

/*!
  \since 4.4

  Returns a string representation of this context.
  This is useful for debugging.

  \sa backtrace()
*/
QString QScriptContext::toString() const
{
    QScriptContextInfo info(this);
    QString result;

    QString functionName = info.functionName();
    if (functionName.isEmpty()) {
        if (parentContext()) {
            const JSC::CallFrame *frame = QScriptEnginePrivate::frameForContext(this);
            if (info.functionType() == QScriptContextInfo::ScriptFunction)
                result.append(QLatin1String("<anonymous>"));
            else if(frame->callerFrame()->hasHostCallFrameFlag())
                result.append(QLatin1String("<eval>"));
            else
                result.append(QLatin1String("<native>"));
        } else {
            result.append(QLatin1String("<global>"));
        }
    } else {
        result.append(functionName);
    }

    QStringList parameterNames = info.functionParameterNames();
    result.append(QLatin1Char('('));
    for (int i = 0; i < argumentCount(); ++i) {
        if (i > 0)
            result.append(QLatin1String(", "));
        if (i < parameterNames.count()) {
            result.append(parameterNames.at(i));
            result.append(QLatin1String(" = "));
        }
        QScriptValue arg = argument(i);
        if (arg.isString())
            result.append(QLatin1Char('\''));
        result.append(arg.toString());
        if (arg.isString())
            result.append(QLatin1Char('\''));

    }
    result.append(QLatin1Char(')'));

    QString fileName = info.fileName();
    int lineNumber = info.lineNumber();
    result.append(QLatin1String(" at "));
    if (!fileName.isEmpty()) {
        result.append(fileName);
        result.append(QLatin1Char(':'));
    }
    result.append(QString::number(lineNumber));
    return result;
}

/*!
  \internal
  \since 4.5

  Returns the scope chain of this QScriptContext.
*/
QScriptValueList QScriptContext::scopeChain() const
{
    activationObject(); //ensure the creation of the normal scope for native context
    const JSC::CallFrame *frame = QScriptEnginePrivate::frameForContext(this);
    QScriptEnginePrivate *engine = QScript::scriptEngineFromExec(frame);
    QScript::APIShim shim(engine);
    QScriptValueList result;
    JSC::ScopeChainNode *node = frame->scopeChain();
    JSC::ScopeChainIterator it(node);
    for (it = node->begin(); it != node->end(); ++it) {
        JSC::JSObject *object = *it;
        if (!object)
            continue;
        if (object->inherits(&QScript::QScriptActivationObject::info)
            && (static_cast<QScript::QScriptActivationObject*>(object)->delegate() != 0)) {
            // Return the object that property access is being delegated to
            object = static_cast<QScript::QScriptActivationObject*>(object)->delegate();
        }
        result.append(engine->scriptValueFromJSCValue(object));
    }
    return result;
}

/*!
  \internal
  \since 4.5

  Adds the given \a object to the front of this context's scope chain.

  If \a object is not an object, this function does nothing.
*/
void QScriptContext::pushScope(const QScriptValue &object)
{
    activationObject(); //ensure the creation of the normal scope for native context
    if (!object.isObject())
        return;
    else if (object.engine() != engine()) {
        qWarning("QScriptContext::pushScope() failed: "
                 "cannot push an object created in "
                 "a different engine");
        return;
    }
    JSC::CallFrame *frame = QScriptEnginePrivate::frameForContext(this);
    QScriptEnginePrivate *engine = QScript::scriptEngineFromExec(frame);
    QScript::APIShim shim(engine);
    JSC::JSObject *jscObject = JSC::asObject(engine->scriptValueToJSCValue(object));
    if (jscObject == engine->originalGlobalObjectProxy)
        jscObject = engine->originalGlobalObject();
    JSC::ScopeChainNode *scope = frame->scopeChain();
    Q_ASSERT(scope != 0);
    if (!scope->object) {
        // pushing to an "empty" chain
        if (!jscObject->isGlobalObject()) {
            qWarning("QScriptContext::pushScope() failed: initial object in scope chain has to be the Global Object");
            return;
        }
        scope->object = jscObject;
    }
    else
        frame->setScopeChain(scope->push(jscObject));
}

/*!
  \internal
  \since 4.5

  Removes the front object from this context's scope chain, and
  returns the removed object.

  If the scope chain is already empty, this function returns an
  invalid QScriptValue.
*/
QScriptValue QScriptContext::popScope()
{
    activationObject(); //ensure the creation of the normal scope for native context
    JSC::CallFrame *frame = QScriptEnginePrivate::frameForContext(this);
    JSC::ScopeChainNode *scope = frame->scopeChain();
    Q_ASSERT(scope != 0);
    QScriptEnginePrivate *engine = QScript::scriptEngineFromExec(frame);
    QScript::APIShim shim(engine);
    QScriptValue result = engine->scriptValueFromJSCValue(scope->object);
    if (!scope->next) {
        // We cannot have a null scope chain, so just zap the object pointer.
        scope->object = 0;
    } else {
        frame->setScopeChain(scope->pop());
    }
    return result;
}

QT_END_NAMESPACE