summaryrefslogtreecommitdiffstats
path: root/src/script/api/qscriptengineagent.cpp
blob: 741ded177add34201e31b180f0e93c6a2cc42463 (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
/****************************************************************************
**
** Copyright (C) 2009 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.
**
** $QT_BEGIN_LICENSE:LGPL-ONLY$
** 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 "config.h"
#include "qscriptengineagent.h"
#include "qscriptengineagent_p.h"
#include "qscriptengine.h"
#include "qscriptengine_p.h"

#include "CodeBlock.h"
#include "Instruction.h"

QT_BEGIN_NAMESPACE

/*!
  \since 4.4
  \class QScriptEngineAgent

  \brief The QScriptEngineAgent class provides an interface to report events pertaining to QScriptEngine execution.

  \ingroup script


  The QScriptEngineAgent class is the basis of tools that monitor and/or control the execution of a
  QScriptEngine, such as debuggers and profilers.

  To process script loading and unloading events, reimplement the
  scriptLoad() and scriptUnload() functions. scriptLoad() is called
  after the input to QScriptEngine::evaluate() has been parsed, right
  before the given script is executed. The engine assigns each
  script an ID, which is available as one of the arguments to
  scriptLoad(); subsequently, other event handlers can use the ID to
  identify a particular script. One common usage of scriptLoad() is
  to retain the script text, filename and base line number (the
  original input to QScriptEngine::evaluate()), so that other event
  handlers can e.g. map a line number to the corresponding line of
  text.

  scriptUnload() is called when the QScriptEngine has no further use
  for a script; the QScriptEngineAgent may at this point safely
  discard any resources associated with the script (such as the
  script text). Note that after scriptUnload() has been called, the
  QScriptEngine may reuse the relevant script ID for new scripts
  (i.e. as argument to a subsequent call to scriptLoad()).

  Evaluating the following script will result in scriptUnload()
  being called immediately after evaluation has completed:

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

  Evaluating the following script will \b{not} result in a call to
  scriptUnload() when evaluation has completed:

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

  The script isn't unloaded because it defines a function (\c{cube})
  that remains in the script environment after evaluation has
  completed. If a subsequent script removed the \c{cube} function
  (e.g. by setting it to \c{null}), scriptUnload() would be called
  when the function is garbage collected. In general terms, a script
  isn't unloaded until the engine has determined that none of its
  contents is referenced.

  To process script function calls and returns, reimplement the
  functionEntry() and functionExit() functions. functionEntry() is
  called when a script function is about to be executed;
  functionExit() is called when a script function is about to return,
  either normally or due to an exception.

  To process individual script statements, reimplement
  positionChange(). positionChange() is called each time the engine is
  about to execute a new statement of a script, and thus offers the
  finest level of script monitoring.

  To process exceptions, reimplement exceptionThrow() and
  exceptionCatch(). exceptionThrow() is called when a script exception
  is thrown, before it has been handled. exceptionCatch() is called
  when an exception handler is present, and execution is about to be
  resumed at the handler code.

  \sa QScriptEngine::setAgent(), QScriptContextInfo
*/

/*!
  \enum QScriptEngineAgent::Extension

  This enum specifies the possible extensions to a QScriptEngineAgent.

  \value DebuggerInvocationRequest The agent handles \c{debugger} script statements.

  \sa extension()
*/


void QScriptEngineAgentPrivate::attach()
{
    if (engine->originalGlobalObject()->debugger())
        engine->originalGlobalObject()->setDebugger(0);
    JSC::Debugger::attach(engine->originalGlobalObject());
}

void QScriptEngineAgentPrivate::detach()
{
    JSC::Debugger::detach(engine->originalGlobalObject());
}

void QScriptEngineAgentPrivate::returnEvent(const JSC::DebuggerCallFrame& frame, intptr_t sourceID, int lineno)
{
    Q_UNUSED(frame);
    Q_UNUSED(lineno);
    Q_UNUSED(sourceID);
}

void QScriptEngineAgentPrivate::exceptionThrow(const JSC::DebuggerCallFrame& frame, intptr_t sourceID, bool hasHandler)
{
    JSC::CallFrame *oldFrame = engine->currentFrame;
    engine->currentFrame = frame.callFrame();
    QScriptValue value(engine->scriptValueFromJSCValue(frame.exception()));
    q_ptr->exceptionThrow(sourceID, value, hasHandler);
    engine->currentFrame = oldFrame;
    engine->setCurrentException(value);
};

void QScriptEngineAgentPrivate::exceptionCatch(const JSC::DebuggerCallFrame& frame, intptr_t sourceID)
{
    JSC::CallFrame *oldFrame = engine->currentFrame;
    engine->currentFrame = frame.callFrame();
    QScriptValue value(engine->scriptValueFromJSCValue(frame.exception()));
    q_ptr->exceptionCatch(sourceID, value);
    engine->currentFrame = oldFrame;
    engine->clearCurrentException();
}

void QScriptEngineAgentPrivate::atStatement(const JSC::DebuggerCallFrame& frame, intptr_t sourceID, int lineno, int column)
{
    QScript::UStringSourceProviderWithFeedback *source = engine->loadedScripts.value(sourceID);
    Q_ASSERT(source != 0);
    column = source->columnNumberFromOffset(column);
    JSC::CallFrame *oldFrame = engine->currentFrame;
    int oldAgentLineNumber = engine->agentLineNumber;
    engine->currentFrame = frame.callFrame();
    engine->agentLineNumber = lineno;
    q_ptr->positionChange(sourceID, lineno, column);
    engine->currentFrame = oldFrame;
    engine->agentLineNumber = oldAgentLineNumber;
}

void QScriptEngineAgentPrivate::functionExit(const JSC::JSValue& returnValue, intptr_t sourceID)
{
    QScriptValue result = engine->scriptValueFromJSCValue(returnValue);
    q_ptr->functionExit(sourceID, result);
    q_ptr->contextPop();
}

void QScriptEngineAgentPrivate::evaluateStop(const JSC::JSValue& returnValue, intptr_t sourceID)
{
    QScriptValue result = engine->scriptValueFromJSCValue(returnValue);
    q_ptr->functionExit(sourceID, result);
}

void QScriptEngineAgentPrivate::didReachBreakpoint(const JSC::DebuggerCallFrame& frame,
                                                   intptr_t sourceID, int lineno, int column)
{
    if (q_ptr->supportsExtension(QScriptEngineAgent::DebuggerInvocationRequest)) {
        QScript::UStringSourceProviderWithFeedback *source = engine->loadedScripts.value(sourceID);
        Q_ASSERT(source != 0);
        column = source->columnNumberFromOffset(column);
        JSC::CallFrame *oldFrame = engine->currentFrame;
        int oldAgentLineNumber = engine->agentLineNumber;
        engine->currentFrame = frame.callFrame();
        engine->agentLineNumber = lineno;
        QList<QVariant> args;
        args << qint64(sourceID) << lineno << column;
        q_ptr->extension(QScriptEngineAgent::DebuggerInvocationRequest, args);
        engine->currentFrame = oldFrame;
        engine->agentLineNumber = oldAgentLineNumber;
    }
};

/*!
    Constructs a QScriptEngineAgent object for the given \a engine.

    The engine takes ownership of the agent.

    Call QScriptEngine::setAgent() to make this agent the active
    agent.
*/
QScriptEngineAgent::QScriptEngineAgent(QScriptEngine *engine)
        : d_ptr(new QScriptEngineAgentPrivate())
{
    d_ptr->q_ptr = this;
    d_ptr->engine = QScriptEnginePrivate::get(engine);
    d_ptr->engine->ownedAgents.append(this);
}

/*!
  \internal
*/
QScriptEngineAgent::QScriptEngineAgent(QScriptEngineAgentPrivate &dd, QScriptEngine *engine)
    : d_ptr(&dd)
{
    d_ptr->q_ptr = this;
    d_ptr->engine = QScriptEnginePrivate::get(engine);
}

/*!
  Destroys this QScriptEngineAgent.
*/
QScriptEngineAgent::~QScriptEngineAgent()
{
    d_ptr->engine->agentDeleted(this); //### TODO: Can this throw?
}

/*!

  This function is called when the engine has parsed a script and has
  associated it with the given \a id. The id can be used to identify
  this particular script in subsequent event notifications.

  \a program, \a fileName and \a baseLineNumber are the original
  arguments to the QScriptEngine::evaluate() call that triggered this
  event.

  This function is called just before the script is about to be
  evaluated.

  You can reimplement this function to record information about the
  script; for example, by retaining the script text, you can obtain
  the line of text corresponding to a line number in a subsequent
  call to positionChange().

  The default implementation does nothing.

  \sa scriptUnload()
*/
void QScriptEngineAgent::scriptLoad(qint64 id, const QString &program,
                                    const QString &fileName, int baseLineNumber)
{
    Q_UNUSED(id);
    Q_UNUSED(program);
    Q_UNUSED(fileName);
    Q_UNUSED(baseLineNumber);
}

/*!
  This function is called when the engine has discarded the script
  identified by the given \a id.

  You can reimplement this function to clean up any resources you have
  associated with the script.

  The default implementation does nothing.

  \sa scriptLoad()
*/
void QScriptEngineAgent::scriptUnload(qint64 id)
{
    Q_UNUSED(id);
}

/*!
  This function is called when a new script context has been pushed.

  The default implementation does nothing.

  \sa contextPop(), functionEntry()
*/
void QScriptEngineAgent::contextPush()
{
}

/*!
  This function is called when the current script context is about to
  be popped.

  The default implementation does nothing.

  \sa contextPush(), functionExit()
*/
void QScriptEngineAgent::contextPop()
{
}

/*!
  This function is called when a script function is called in the
  engine. If the script function is not a native Qt Script function,
  it resides in the script identified by \a scriptId; otherwise, \a
  scriptId is -1.

  This function is called just before execution of the script function
  begins.  You can obtain the QScriptContext associated with the
  function call with QScriptEngine::currentContext(). The arguments
  passed to the function are available.

  Reimplement this function to handle this event. For example, a
  debugger implementation could reimplement this function (and
  functionExit()) to keep track of the call stack and provide
  step-over functionality.

  The default implementation does nothing.

  \sa functionExit(), positionChange(), QScriptEngine::currentContext()
*/
void QScriptEngineAgent::functionEntry(qint64 scriptId)
{
    Q_UNUSED(scriptId);
}

/*!
  This function is called when the currently executing script function
  is about to return. If the script function is not a native Qt Script
  function, it resides in the script identified by \a scriptId;
  otherwise, \a scriptId is -1. The \a returnValue is the value that
  the script function will return.

  This function is called just before the script function returns.
  You can still access the QScriptContext associated with the
  script function call with QScriptEngine::currentContext().

  If the engine's
  \l{QScriptEngine::hasUncaughtException()}{hasUncaughtException}()
  function returns true, the script function is exiting due to an
  exception; otherwise, the script function is returning normally.

  Reimplement this function to handle this event; typically you will
  then also want to reimplement functionEntry().

  The default implementation does nothing.

  \sa functionEntry(), QScriptEngine::hasUncaughtException()
*/
void QScriptEngineAgent::functionExit(qint64 scriptId,
                                      const QScriptValue &returnValue)
{
    Q_UNUSED(scriptId);
    Q_UNUSED(returnValue);
}

/*!
  This function is called when the engine is about to execute a new
  statement in the script identified by \a scriptId.  The statement
  begins on the line and column specified by \a lineNumber and \a
  columnNumber.  This event is not generated for native Qt Script
  functions.

  Reimplement this function to handle this event. For example, a
  debugger implementation could reimplement this function to provide
  line-by-line stepping, and a profiler implementation could use it to
  count the number of times each statement is executed.

  The default implementation does nothing.

  \sa scriptLoad(), functionEntry()
*/
void QScriptEngineAgent::positionChange(qint64 scriptId,
                                        int lineNumber, int columnNumber)
{
    Q_UNUSED(scriptId);
    Q_UNUSED(lineNumber);
    Q_UNUSED(columnNumber);
}

/*!
  This function is called when the given \a exception has occurred in
  the engine, in the script identified by \a scriptId. If the
  exception was thrown by a native Qt Script function, \a scriptId is
  -1.

  If \a hasHandler is true, there is a \c{catch} or \c{finally} block
  that will handle the exception. If \a hasHandler is false, there is
  no handler for the exception.

  Reimplement this function if you want to handle this event. For
  example, a debugger can notify the user when an uncaught exception
  occurs (i.e. \a hasHandler is false).

  The default implementation does nothing.

  \sa exceptionCatch()
*/
void QScriptEngineAgent::exceptionThrow(qint64 scriptId,
                                        const QScriptValue &exception,
                                        bool hasHandler)
{
    Q_UNUSED(scriptId);
    Q_UNUSED(exception);
    Q_UNUSED(hasHandler);
}

/*!
  This function is called when the given \a exception is about to be
  caught, in the script identified by \a scriptId.

  Reimplement this function if you want to handle this event.

  The default implementation does nothing.

  \sa exceptionThrow()
*/
void QScriptEngineAgent::exceptionCatch(qint64 scriptId,
                                        const QScriptValue &exception)
{
    Q_UNUSED(scriptId);
    Q_UNUSED(exception);
}

#if 0
/*!
  This function is called when a property of the given \a object has
  been added, changed or removed.

  Reimplement this function if you want to handle this event.

  The default implementation does nothing.
*/
void QScriptEngineAgent::propertyChange(qint64 scriptId,
                                        const QScriptValue &object,
                                        const QString &propertyName,
                                        PropertyChange change)
{
    Q_UNUSED(scriptId);
    Q_UNUSED(object);
    Q_UNUSED(propertyName);
    Q_UNUSED(change);
}
#endif

/*!
  Returns true if the QScriptEngineAgent supports the given \a
  extension; otherwise, false is returned. By default, no extensions
  are supported.

  \sa extension()
*/
bool QScriptEngineAgent::supportsExtension(Extension extension) const
{
    Q_UNUSED(extension);
    return false;
}

/*!
  This virtual function can be reimplemented in a QScriptEngineAgent
  subclass to provide support for extensions. The optional \a argument
  can be provided as input to the \a extension; the result must be
  returned in the form of a QVariant. You can call supportsExtension()
  to check if an extension is supported by the QScriptEngineAgent.  By
  default, no extensions are supported, and this function returns an
  invalid QVariant.

  If you implement the DebuggerInvocationRequest extension, Qt Script
  will call this function when a \c{debugger} statement is encountered
  in a script. The \a argument is a QVariantList containing three
  items: The first item is the scriptId (a qint64), the second item is
  the line number (an int), and the third item is the column number
  (an int).

  \sa supportsExtension()
*/
QVariant QScriptEngineAgent::extension(Extension extension,
                                       const QVariant &argument)
{
    Q_UNUSED(extension);
    Q_UNUSED(argument);
    return QVariant();
}

/*!
  Returns the QScriptEngine that this agent is associated with.
*/
QScriptEngine *QScriptEngineAgent::engine() const
{
    Q_D(const QScriptEngineAgent);
    return QScriptEnginePrivate::get(d->engine);
}

QT_END_NAMESPACE