src/declarative/qml/qdeclarativebinding.cpp

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  41
  42 #include "qdeclarativebinding_p.h"
  43 #include "qdeclarativebinding_p_p.h"
  44
  45 #include "qdeclarative.h"
  46 #include "qdeclarativecontext.h"
  47 #include "qdeclarativeinfo.h"
  48 #include "qdeclarativecompiler_p.h"
  49 #include "qdeclarativedata_p.h"
  50 #include <private/qdeclarativedebugtrace_p.h>
  51 #include <private/qdeclarativetrace_p.h>
  52
  53 #include <QVariant>
  54 #include <QtCore/qdebug.h>
  55
  56 QT_BEGIN_NAMESPACE
  57
  58 QDeclarativeAbstractBinding::QDeclarativeAbstractBinding()
  59 : m_object(0), m_propertyIndex(-1), m_mePtr(0), m_prevBinding(0), m_nextBinding(0)
  60 {
  61 }
  62
  63 QDeclarativeAbstractBinding::~QDeclarativeAbstractBinding()
  64 {
  65     Q_ASSERT(m_prevBinding == 0);
  66     Q_ASSERT(m_mePtr == 0);
  67 }
  68
  69 /*!
  70 Destroy the binding.  Use this instead of calling delete.
  71
  72 Bindings are free to implement their own memory management, so the delete operator is not
  73 necessarily safe.  The default implementation clears the binding, removes it from the object
  74 and calls delete.
  75 */
  76 void QDeclarativeAbstractBinding::destroy()
  77 {
  78     removeFromObject();
  79     clear();
  80
  81     delete this;
  82 }
  83
  84 /*!
  85 Add this binding to \a object.
  86
  87 This transfers ownership of the binding to the object, marks the object's property as
  88 being bound.
  89
  90 However, it does not enable the binding itself or call update() on it.
  91 */
  92 void QDeclarativeAbstractBinding::addToObject(QObject *object, int index)
  93 {
  94     Q_ASSERT(object);
  95
  96     if (m_object == object && m_propertyIndex == index)
  97         return;
  98
  99     removeFromObject();
 100
 101     Q_ASSERT(!m_prevBinding);
 102
 103     m_object = object;
 104     m_propertyIndex = index;
 105
 106     QDeclarativeData *data = QDeclarativeData::get(object, true);
 107
 108     if (index & 0xFF000000) {
 109         // Value type
 110
 111         int coreIndex = index & 0xFFFFFF;
 112
 113         // Find the value type proxy (if there is one)
 114         QDeclarativeValueTypeProxyBinding *proxy = 0;
 115         if (data->hasBindingBit(coreIndex)) {
 116             QDeclarativeAbstractBinding *b = data->bindings;
 117             while (b && b->propertyIndex() != coreIndex)
 118                 b = b->m_nextBinding;
 119             Q_ASSERT(b && b->bindingType() == QDeclarativeAbstractBinding::ValueTypeProxy);
 120             proxy = static_cast<QDeclarativeValueTypeProxyBinding *>(b);
 121         }
 122
 123         if (!proxy) {
 124             proxy = new QDeclarativeValueTypeProxyBinding(object, coreIndex);
 125             proxy->addToObject(object, coreIndex);
 126         }
 127
 128         m_nextBinding = proxy->m_bindings;
 129         if (m_nextBinding) m_nextBinding->m_prevBinding = &m_nextBinding;
 130         m_prevBinding = &proxy->m_bindings;
 131         proxy->m_bindings = this;
 132
 133     } else {
 134         m_nextBinding = data->bindings;
 135         if (m_nextBinding) m_nextBinding->m_prevBinding = &m_nextBinding;
 136         m_prevBinding = &data->bindings;
 137         data->bindings = this;
 138
 139         data->setBindingBit(m_object, index);
 140     }
 141 }
 142
 143 /*!
 144 Remove the binding from the object.
 145 */
 146 void QDeclarativeAbstractBinding::removeFromObject()
 147 {
 148     if (m_prevBinding) {
 149         int index = propertyIndex();
 150
 151         *m_prevBinding = m_nextBinding;
 152         if (m_nextBinding) m_nextBinding->m_prevBinding = m_prevBinding;
 153         m_prevBinding = 0;
 154         m_nextBinding = 0;
 155
 156         if (index & 0xFF000000) {
 157             // Value type - we don't remove the proxy from the object.  It will sit their happily
 158             // doing nothing until it is removed by a write, a binding change or it is reused
 159             // to hold more sub-bindings.
 160         } else if (m_object) {
 161             QDeclarativeData *data = QDeclarativeData::get(m_object, false);
 162             if (data) data->clearBindingBit(index);
 163         }
 164
 165         m_object = 0;
 166         m_propertyIndex = -1;
 167     }
 168 }
 169
 170 static void bindingDummyDeleter(QDeclarativeAbstractBinding *)
 171 {
 172 }
 173
 174 QDeclarativeAbstractBinding::Pointer QDeclarativeAbstractBinding::weakPointer()
 175 {
 176     if (m_selfPointer.isNull())
 177         m_selfPointer = QSharedPointer<QDeclarativeAbstractBinding>(this, bindingDummyDeleter);
 178
 179     return m_selfPointer.toWeakRef();
 180 }
 181
 182 void QDeclarativeAbstractBinding::clear()
 183 {
 184     if (m_mePtr) {
 185         *m_mePtr = 0;
 186         m_mePtr = 0;
 187     }
 188 }
 189
 190 QString QDeclarativeAbstractBinding::expression() const
 191 {
 192     return QLatin1String("<Unknown>");
 193 }
 194
 195 QObject *QDeclarativeAbstractBinding::object() const
 196 {
 197     return m_object;
 198 }
 199
 200 int QDeclarativeAbstractBinding::propertyIndex() const
 201 {
 202     return m_propertyIndex;
 203 }
 204
 205 void QDeclarativeAbstractBinding::setEnabled(bool enabled, QDeclarativePropertyPrivate::WriteFlags flags)
 206 {
 207     if (enabled) update(flags);
 208 }
 209
 210 QDeclarativeBinding::Identifier QDeclarativeBinding::Invalid = -1;
 211
 212 void QDeclarativeBindingPrivate::refresh()
 213 {
 214     Q_Q(QDeclarativeBinding);
 215     q->update();
 216 }
 217
 218 QDeclarativeBindingPrivate::QDeclarativeBindingPrivate()
 219 : updating(false), enabled(false)
 220 {
 221 }
 222
 223 QDeclarativeBindingPrivate::~QDeclarativeBindingPrivate()
 224 {
 225 }
 226
 227 QDeclarativeBinding *
 228 QDeclarativeBinding::createBinding(Identifier id, QObject *obj, QDeclarativeContext *ctxt,
 229                                    const QString &url, int lineNumber, QObject *parent)
 230 {
 231     if (id < 0)
 232         return 0;
 233
 234     QDeclarativeContextData *ctxtdata = QDeclarativeContextData::get(ctxt);
 235
 236     QDeclarativeEnginePrivate *engine = QDeclarativeEnginePrivate::get(ctxt->engine());
 237     QDeclarativeCompiledData *cdata = 0;
 238     QDeclarativeTypeData *typeData = 0;
 239     if (engine && ctxtdata && !ctxtdata->url.isEmpty()) {
 240         typeData = engine->typeLoader.get(ctxtdata->url);
 241         cdata = typeData->compiledData();
 242     }
 243     QDeclarativeBinding *rv = cdata ? new QDeclarativeBinding(cdata->primitives.at(id), true, obj, ctxtdata, url, lineNumber, 0, parent) : 0;
 244     if (cdata)
 245         cdata->release();
 246     if (typeData)
 247         typeData->release();
 248     return rv;
 249 }
 250
 251 QDeclarativeBinding::QDeclarativeBinding(const QString &str, QObject *obj, QDeclarativeContext *ctxt,
 252                                          QObject *parent)
 253 : QDeclarativeExpression(QDeclarativeContextData::get(ctxt), obj, str, *new QDeclarativeBindingPrivate)
 254 {
 255     setParent(parent);
 256     setNotifyOnValueChanged(true);
 257 }
 258
 259 QDeclarativeBinding::QDeclarativeBinding(const QString &str, QObject *obj, QDeclarativeContextData *ctxt,
 260                                          QObject *parent)
 261 : QDeclarativeExpression(ctxt, obj, str, *new QDeclarativeBindingPrivate)
 262 {
 263     setParent(parent);
 264     setNotifyOnValueChanged(true);
 265 }
 266
 267 QDeclarativeBinding::QDeclarativeBinding(const QString &str, bool isRewritten, QObject *obj,
 268                                          QDeclarativeContextData *ctxt,
 269                                          const QString &url, int lineNumber, int columnNumber,
 270                                          QObject *parent)
 271 : QDeclarativeExpression(ctxt, obj, str, isRewritten, url, lineNumber, columnNumber, *new QDeclarativeBindingPrivate)
 272 {
 273     Q_D(QDeclarativeBinding);
 274
 275     setParent(parent);
 276     setNotifyOnValueChanged(true);
 277 }
 278
 279 /*!
 280     \internal
 281
 282     To avoid exposing v8 in the public API, functionPtr must be a pointer to a v8::Handle<v8::Function>.
 283     For example:
 284         v8::Handle<v8::Function> function;
 285         new QDeclarativeBInding(&function, scope, ctxt);
 286  */
 287 QDeclarativeBinding::QDeclarativeBinding(void *functionPtr, QObject *obj, QDeclarativeContextData *ctxt,
 288                                          QObject *parent)
 289 : QDeclarativeExpression(ctxt, obj, functionPtr, *new QDeclarativeBindingPrivate)
 290 {
 291     setParent(parent);
 292     setNotifyOnValueChanged(true);
 293 }
 294
 295 QDeclarativeBinding::~QDeclarativeBinding()
 296 {
 297 }
 298
 299 void QDeclarativeBinding::setTarget(const QDeclarativeProperty &prop)
 300 {
 301     Q_D(QDeclarativeBinding);
 302     d->property = prop;
 303
 304     update();
 305 }
 306
 307 void QDeclarativeBinding::setTarget(QObject *object,
 308                                     const QDeclarativePropertyData &core,
 309                                     QDeclarativeContextData *ctxt)
 310 {
 311     Q_D(QDeclarativeBinding);
 312     d->property = QDeclarativePropertyPrivate::restore(object, core, ctxt);
 313
 314     update();
 315 }
 316
 317 QDeclarativeProperty QDeclarativeBinding::property() const
 318 {
 319    Q_D(const QDeclarativeBinding);
 320    return d->property;
 321 }
 322
 323 void QDeclarativeBinding::setEvaluateFlags(EvaluateFlags flags)
 324 {
 325     Q_D(QDeclarativeBinding);
 326     d->setRequiresThisObject(flags & RequiresThisObject);
 327 }
 328
 329 QDeclarativeBinding::EvaluateFlags QDeclarativeBinding::evaluateFlags() const
 330 {
 331     Q_D(const QDeclarativeBinding);
 332     return d->requiresThisObject()?RequiresThisObject:None;
 333 }
 334
 335
 336 class QDeclarativeBindingProfiler {
 337 public:
 338     QDeclarativeBindingProfiler(QDeclarativeBinding *bind)
 339     {
 340         QDeclarativeDebugTrace::startRange(QDeclarativeDebugTrace::Binding);
 341         QDeclarativeDebugTrace::rangeData(QDeclarativeDebugTrace::Binding, bind->expression());
 342         QDeclarativeDebugTrace::rangeLocation(QDeclarativeDebugTrace::Binding, bind->sourceFile(), bind->lineNumber(), bind->columnNumber());
 343     }
 344
 345     ~QDeclarativeBindingProfiler()
 346     {
 347         QDeclarativeDebugTrace::endRange(QDeclarativeDebugTrace::Binding);
 348     }
 349 };
 350
 351 void QDeclarativeBinding::update(QDeclarativePropertyPrivate::WriteFlags flags)
 352 {
 353     Q_D(QDeclarativeBinding);
 354
 355     if (!d->enabled || !d->context() || !d->context()->isValid())
 356         return;
 357
 358     QDeclarativeTrace trace("General Binding Update");
 359     trace.addDetail("URL", d->url);
 360     trace.addDetail("Line", d->line);
 361     trace.addDetail("Column", d->columnNumber);
 362
 363     if (!d->updating) {
 364         QDeclarativeBindingProfiler prof(this);
 365         d->updating = true;
 366
 367         QDeleteWatcher watcher(d);
 368
 369         if (d->property.propertyType() == qMetaTypeId<QDeclarativeBinding *>()) {
 370
 371             int idx = d->property.index();
 372             Q_ASSERT(idx != -1);
 373
 374             QDeclarativeBinding *t = this;
 375             int status = -1;
 376             void *a[] = { &t, 0, &status, &flags };
 377             QMetaObject::metacall(d->property.object(),
 378                                   QMetaObject::WriteProperty,
 379                                   idx, a);
 380
 381         } else {
 382             QDeclarativeEnginePrivate *ep = QDeclarativeEnginePrivate::get(d->context()->engine);
 383             ep->referenceScarceResources();
 384
 385             bool isUndefined = false;
 386
 387             v8::HandleScope handle_scope;
 388             v8::Context::Scope scope(ep->v8engine()->context());
 389             v8::Local<v8::Value> result = d->v8value(0, &isUndefined);
 390
 391             trace.event("writing binding result");
 392
 393             bool needsErrorData = false;
 394             if (!watcher.wasDeleted() && !d->error.isValid())
 395                 needsErrorData = !QDeclarativePropertyPrivate::writeBinding(d->property, d, result,
 396                                                                             isUndefined, flags);
 397
 398             if (!watcher.wasDeleted()) {
 399
 400                 if (needsErrorData) {
 401                     QUrl url = QUrl(d->url);
 402                     int line = d->line;
 403                     if (url.isEmpty()) url = QUrl(QLatin1String("<Unknown File>"));
 404
 405                     d->error.setUrl(url);
 406                     d->error.setLine(line);
 407                     d->error.setColumn(-1);
 408                 }
 409
 410                 if (d->error.isValid()) {
 411                     if (!d->addError(ep)) ep->warning(this->error());
 412                 } else {
 413                     d->removeError();
 414                 }
 415
 416             }
 417
 418             ep->dereferenceScarceResources();
 419         }
 420
 421         if (!watcher.wasDeleted())
 422             d->updating = false;
 423     } else {
 424         QDeclarativeBindingPrivate::printBindingLoopError(d->property);
 425     }
 426 }
 427
 428 void QDeclarativeBindingPrivate::printBindingLoopError(QDeclarativeProperty &prop)
 429 {
 430     qmlInfo(prop.object()) << QDeclarativeBinding::tr("Binding loop detected for property \"%1\"").arg(prop.name());
 431 }
 432
 433 void QDeclarativeBindingPrivate::expressionChanged()
 434 {
 435     Q_Q(QDeclarativeBinding);
 436     q->update();
 437 }
 438
 439 void QDeclarativeBinding::setEnabled(bool e, QDeclarativePropertyPrivate::WriteFlags flags)
 440 {
 441     Q_D(QDeclarativeBinding);
 442     d->enabled = e;
 443     setNotifyOnValueChanged(e);
 444
 445     if (e)
 446         update(flags);
 447 }
 448
 449 bool QDeclarativeBinding::enabled() const
 450 {
 451     Q_D(const QDeclarativeBinding);
 452
 453     return d->enabled;
 454 }
 455
 456 QString QDeclarativeBinding::expression() const
 457 {
 458     return QDeclarativeExpression::expression();
 459 }
 460
 461 QDeclarativeValueTypeProxyBinding::QDeclarativeValueTypeProxyBinding(QObject *o, int index)
 462 : m_object(o), m_index(index), m_bindings(0)
 463 {
 464 }
 465
 466 QDeclarativeValueTypeProxyBinding::~QDeclarativeValueTypeProxyBinding()
 467 {
 468     while (m_bindings) {
 469         QDeclarativeAbstractBinding *binding = m_bindings;
 470         binding->setEnabled(false, 0);
 471         binding->destroy();
 472     }
 473 }
 474
 475 void QDeclarativeValueTypeProxyBinding::setEnabled(bool e, QDeclarativePropertyPrivate::WriteFlags flags)
 476 {
 477     if (e) {
 478         QDeclarativeAbstractBinding *bindings = m_bindings;
 479         recursiveEnable(bindings, flags);
 480     } else {
 481         QDeclarativeAbstractBinding *bindings = m_bindings;
 482         recursiveDisable(bindings);
 483     }
 484 }
 485
 486 void QDeclarativeValueTypeProxyBinding::recursiveEnable(QDeclarativeAbstractBinding *b, QDeclarativePropertyPrivate::WriteFlags flags)
 487 {
 488     if (!b)
 489         return;
 490
 491     recursiveEnable(b->m_nextBinding, flags);
 492
 493     if (b)
 494         b->setEnabled(true, flags);
 495 }
 496
 497 void QDeclarativeValueTypeProxyBinding::recursiveDisable(QDeclarativeAbstractBinding *b)
 498 {
 499     if (!b)
 500         return;
 501
 502     recursiveDisable(b->m_nextBinding);
 503
 504     if (b)
 505         b->setEnabled(false, 0);
 506 }
 507
 508 void QDeclarativeValueTypeProxyBinding::update(QDeclarativePropertyPrivate::WriteFlags)
 509 {
 510 }
 511
 512 QDeclarativeAbstractBinding *QDeclarativeValueTypeProxyBinding::binding(int propertyIndex)
 513 {
 514     QDeclarativeAbstractBinding *binding = m_bindings;
 515
 516     while (binding && binding->propertyIndex() != propertyIndex)
 517         binding = binding->m_nextBinding;
 518
 519     return binding;
 520 }
 521
 522 /*!
 523 Removes a collection of bindings, corresponding to the set bits in \a mask.
 524 */
 525 void QDeclarativeValueTypeProxyBinding::removeBindings(quint32 mask)
 526 {
 527     QDeclarativeAbstractBinding *binding = m_bindings;
 528     while (binding) {
 529         if (mask & (1 << (binding->propertyIndex() >> 24))) {
 530             QDeclarativeAbstractBinding *remove = binding;
 531             binding = remove->m_nextBinding;
 532             *remove->m_prevBinding = remove->m_nextBinding;
 533             if (remove->m_nextBinding) remove->m_nextBinding->m_prevBinding = remove->m_prevBinding;
 534             remove->m_prevBinding = 0;
 535             remove->m_nextBinding = 0;
 536             remove->destroy();
 537         } else {
 538             binding = binding->m_nextBinding;
 539         }
 540     }
 541 }
 542
 543 QT_END_NAMESPACE