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 void QDeclarativeBinding::update(QDeclarativePropertyPrivate::WriteFlags flags)
 336 {
 337     Q_D(QDeclarativeBinding);
 338
 339     if (!d->enabled || !d->context() || !d->context()->isValid())
 340         return;
 341
 342     QDeclarativeTrace trace("General Binding Update");
 343     trace.addDetail("URL", d->url);
 344     trace.addDetail("Line", d->line);
 345     trace.addDetail("Column", d->columnNumber);
 346
 347     if (!d->updating) {
 348         QDeclarativeBindingProfiler prof(d->url, d->line, d->column);
 349         prof.addDetail(expression());
 350         d->updating = true;
 351
 352         QDeleteWatcher watcher(d);
 353
 354         if (d->property.propertyType() == qMetaTypeId<QDeclarativeBinding *>()) {
 355
 356             int idx = d->property.index();
 357             Q_ASSERT(idx != -1);
 358
 359             QDeclarativeBinding *t = this;
 360             int status = -1;
 361             void *a[] = { &t, 0, &status, &flags };
 362             QMetaObject::metacall(d->property.object(),
 363                                   QMetaObject::WriteProperty,
 364                                   idx, a);
 365
 366         } else {
 367             QDeclarativeEnginePrivate *ep = QDeclarativeEnginePrivate::get(d->context()->engine);
 368             ep->referenceScarceResources();
 369
 370             bool isUndefined = false;
 371
 372             v8::HandleScope handle_scope;
 373             v8::Context::Scope scope(ep->v8engine()->context());
 374             v8::Local<v8::Value> result = d->v8value(0, &isUndefined);
 375
 376             trace.event("writing binding result");
 377
 378             bool needsErrorData = false;
 379             if (!watcher.wasDeleted() && !d->error.isValid())
 380                 needsErrorData = !QDeclarativePropertyPrivate::writeBinding(d->property, d, result,
 381                                                                             isUndefined, flags);
 382
 383             if (!watcher.wasDeleted()) {
 384
 385                 if (needsErrorData) {
 386                     QUrl url = QUrl(d->url);
 387                     int line = d->line;
 388                     if (url.isEmpty()) url = QUrl(QLatin1String("<Unknown File>"));
 389
 390                     d->error.setUrl(url);
 391                     d->error.setLine(line);
 392                     d->error.setColumn(-1);
 393                 }
 394
 395                 if (d->error.isValid()) {
 396                     if (!d->addError(ep)) ep->warning(this->error());
 397                 } else {
 398                     d->removeError();
 399                 }
 400
 401             }
 402
 403             ep->dereferenceScarceResources();
 404         }
 405
 406         if (!watcher.wasDeleted())
 407             d->updating = false;
 408     } else {
 409         QDeclarativeBindingPrivate::printBindingLoopError(d->property);
 410     }
 411 }
 412
 413 void QDeclarativeBindingPrivate::printBindingLoopError(QDeclarativeProperty &prop)
 414 {
 415     qmlInfo(prop.object()) << QDeclarativeBinding::tr("Binding loop detected for property \"%1\"").arg(prop.name());
 416 }
 417
 418 void QDeclarativeBindingPrivate::expressionChanged()
 419 {
 420     Q_Q(QDeclarativeBinding);
 421     q->update();
 422 }
 423
 424 void QDeclarativeBinding::setEnabled(bool e, QDeclarativePropertyPrivate::WriteFlags flags)
 425 {
 426     Q_D(QDeclarativeBinding);
 427     d->enabled = e;
 428     setNotifyOnValueChanged(e);
 429
 430     if (e)
 431         update(flags);
 432 }
 433
 434 bool QDeclarativeBinding::enabled() const
 435 {
 436     Q_D(const QDeclarativeBinding);
 437
 438     return d->enabled;
 439 }
 440
 441 QString QDeclarativeBinding::expression() const
 442 {
 443     return QDeclarativeExpression::expression();
 444 }
 445
 446 QDeclarativeValueTypeProxyBinding::QDeclarativeValueTypeProxyBinding(QObject *o, int index)
 447 : m_object(o), m_index(index), m_bindings(0)
 448 {
 449 }
 450
 451 QDeclarativeValueTypeProxyBinding::~QDeclarativeValueTypeProxyBinding()
 452 {
 453     while (m_bindings) {
 454         QDeclarativeAbstractBinding *binding = m_bindings;
 455         binding->setEnabled(false, 0);
 456         binding->destroy();
 457     }
 458 }
 459
 460 void QDeclarativeValueTypeProxyBinding::setEnabled(bool e, QDeclarativePropertyPrivate::WriteFlags flags)
 461 {
 462     if (e) {
 463         QDeclarativeAbstractBinding *bindings = m_bindings;
 464         recursiveEnable(bindings, flags);
 465     } else {
 466         QDeclarativeAbstractBinding *bindings = m_bindings;
 467         recursiveDisable(bindings);
 468     }
 469 }
 470
 471 void QDeclarativeValueTypeProxyBinding::recursiveEnable(QDeclarativeAbstractBinding *b, QDeclarativePropertyPrivate::WriteFlags flags)
 472 {
 473     if (!b)
 474         return;
 475
 476     recursiveEnable(b->m_nextBinding, flags);
 477
 478     if (b)
 479         b->setEnabled(true, flags);
 480 }
 481
 482 void QDeclarativeValueTypeProxyBinding::recursiveDisable(QDeclarativeAbstractBinding *b)
 483 {
 484     if (!b)
 485         return;
 486
 487     recursiveDisable(b->m_nextBinding);
 488
 489     if (b)
 490         b->setEnabled(false, 0);
 491 }
 492
 493 void QDeclarativeValueTypeProxyBinding::update(QDeclarativePropertyPrivate::WriteFlags)
 494 {
 495 }
 496
 497 QDeclarativeAbstractBinding *QDeclarativeValueTypeProxyBinding::binding(int propertyIndex)
 498 {
 499     QDeclarativeAbstractBinding *binding = m_bindings;
 500
 501     while (binding && binding->propertyIndex() != propertyIndex)
 502         binding = binding->m_nextBinding;
 503
 504     return binding;
 505 }
 506
 507 /*!
 508 Removes a collection of bindings, corresponding to the set bits in \a mask.
 509 */
 510 void QDeclarativeValueTypeProxyBinding::removeBindings(quint32 mask)
 511 {
 512     QDeclarativeAbstractBinding *binding = m_bindings;
 513     while (binding) {
 514         if (mask & (1 << (binding->propertyIndex() >> 24))) {
 515             QDeclarativeAbstractBinding *remove = binding;
 516             binding = remove->m_nextBinding;
 517             *remove->m_prevBinding = remove->m_nextBinding;
 518             if (remove->m_nextBinding) remove->m_nextBinding->m_prevBinding = remove->m_prevBinding;
 519             remove->m_prevBinding = 0;
 520             remove->m_nextBinding = 0;
 521             remove->destroy();
 522         } else {
 523             binding = binding->m_nextBinding;
 524         }
 525     }
 526 }
 527
 528 QT_END_NAMESPACE