path: root/src/declarative/qml/qdeclarativecontext.cpp

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#include "qdeclarativecontext.h"
#include "qdeclarativecontext_p.h"

#include "qdeclarativeexpression_p.h"
#include "qdeclarativeengine_p.h"
#include "qdeclarativeengine.h"
#include "qdeclarativecompiledbindings_p.h"
#include "qdeclarativeinfo.h"

#include <qscriptengine.h>
#include <QtCore/qvarlengtharray.h>
#include <QtCore/qdebug.h>

#include <private/qscriptdeclarativeclass_p.h>

QT_BEGIN_NAMESPACE

QDeclarativeContextPrivate::QDeclarativeContextPrivate()
: parent(0), engine(0), isInternal(false), propertyNames(0), 
  notifyIndex(-1), highPriorityCount(0), imports(0), expressions(0), contextObjects(0),
  idValues(0), idValueCount(0), optimizedBindings(0)
{
}

void QDeclarativeContextPrivate::addScript(const QDeclarativeParser::Object::ScriptBlock &script, QObject *scopeObject)
{
    Q_Q(QDeclarativeContext);

    if (!engine) 
        return;

    QDeclarativeEnginePrivate *enginePriv = QDeclarativeEnginePrivate::get(engine);
    QScriptEngine *scriptEngine = QDeclarativeEnginePrivate::getScriptEngine(engine);

    QScriptContext *scriptContext = QScriptDeclarativeClass::pushCleanContext(scriptEngine);
    scriptContext->pushScope(enginePriv->contextClass->newContext(q, scopeObject));
    
    QScriptValue scope = scriptEngine->newObject();
    scriptContext->setActivationObject(scope);

    for (int ii = 0; ii < script.codes.count(); ++ii) {
        scriptEngine->evaluate(script.codes.at(ii), script.files.at(ii), script.lineNumbers.at(ii));

        if (scriptEngine->hasUncaughtException()) {
            QDeclarativeError error;
            QDeclarativeExpressionPrivate::exceptionToError(scriptEngine, error);
            qWarning().nospace() << qPrintable(error.toString());
        }
    }

    scriptEngine->popContext();

    scripts.append(scope);
}

void QDeclarativeContextPrivate::destroyed(ContextGuard *guard)
{
    Q_Q(QDeclarativeContext);

    // process of being deleted (which is *probably* why obj has been destroyed
    // anyway), as we're about to get deleted which will invalidate all the
    // expressions that could depend on us
    QObject *parent = q->parent();
    if (parent && QObjectPrivate::get(parent)->wasDeleted) 
        return;

    while(guard->bindings) {
        QObject *o = guard->bindings->target;
        int mi = guard->bindings->methodIndex;
        guard->bindings->clear();
        if (o) o->qt_metacall(QMetaObject::InvokeMetaMethod, mi, 0);
    }

    for (int ii = 0; ii < idValueCount; ++ii) {
        if (&idValues[ii] == guard) {
            QMetaObject::activate(q, ii + notifyIndex, 0);
            return;
        }
    }
}

void QDeclarativeContextPrivate::init()
{
    Q_Q(QDeclarativeContext);

    if (parent) 
        parent->d_func()->childContexts.insert(q);
}

/*!
    \class QDeclarativeContext
  \since 4.7
    \brief The QDeclarativeContext class defines a context within a QML engine.
    \mainclass

    Contexts allow data to be exposed to the QML components instantiated by the
    QML engine.

    Each QDeclarativeContext contains a set of properties, distinct from
    its QObject properties, that allow data to be
    explicitly bound to a context by name.  The context properties are defined or
    updated by calling QDeclarativeContext::setContextProperty().  The following example shows
    a Qt model being bound to a context and then accessed from a QML file.

    \code
    QDeclarativeEngine engine;
    QDeclarativeContext context(engine.rootContext());
    context.setContextProperty("myModel", modelData);

    QDeclarativeComponent component(&engine, "ListView { model=myModel }");
    component.create(&context);
    \endcode

    To simplify binding and maintaining larger data sets, QObject's can be
    added to a QDeclarativeContext.  These objects are known as the context's default
    objects.  In this case all the properties of the QObject are
    made available by name in the context, as though they were all individually
    added by calling QDeclarativeContext::setContextProperty().  Changes to the property's
    values are detected through the property's notify signal.  This method is
    also slightly more faster than manually adding property values.

    The following example has the same effect as the one above, but it is
    achieved using a default object.

    \code
    class MyDataSet : ... {
        ...
        Q_PROPERTY(QAbstractItemModel *myModel READ model NOTIFY modelChanged)
        ...
    };

    MyDataSet myDataSet;
    QDeclarativeEngine engine;
    QDeclarativeContext context(engine.rootContext());
    context.addDefaultObject(&myDataSet);

    QDeclarativeComponent component(&engine, "ListView { model=myModel }");
    component.create(&context);
    \endcode

    Default objects added first take precedence over those added later.  All properties 
    added explicitly by QDeclarativeContext::setContextProperty() take precedence over default 
    object properties.

    Contexts are hierarchal, with the \l {QDeclarativeEngine::rootContext()}{root context}
    being created by the QDeclarativeEngine.  A component instantiated in a given context
    has access to that context's data, as well as the data defined by its
    ancestor contexts.  Data values (including those added implicitly by the
    default objects) in a context override those in ancestor contexts.  Data
    that should be available to all components instantiated by the QDeclarativeEngine
    should be added to the \l {QDeclarativeEngine::rootContext()}{root context}.

    In the following example,

    \code
    QDeclarativeEngine engine;
    QDeclarativeContext context1(engine.rootContext());
    QDeclarativeContext context2(&context1);
    QDeclarativeContext context3(&context2);

    context1.setContextProperty("a", 12);
    context2.setContextProperty("b", 13);
    context3.setContextProperty("a", 14);
    context3.setContextProperty("c", 14);
    \endcode

    a QML component instantiated in context1 would have access to the "a" data,
    a QML component instantiated in context2 would have access to the "a" and
    "b" data, and a QML component instantiated in context3 would have access to
    the "a", "b" and "c" data - although its "a" data would return 14, unlike
    that in context1 or context2.
*/

/*! \internal */
QDeclarativeContext::QDeclarativeContext(QDeclarativeEngine *e, bool)
: QObject(*(new QDeclarativeContextPrivate))
{
    Q_D(QDeclarativeContext);
    d->engine = e;
    d->init();
}

/*!
    Create a new QDeclarativeContext as a child of \a engine's root context, and the
    QObject \a parent.
*/
QDeclarativeContext::QDeclarativeContext(QDeclarativeEngine *engine, QObject *parent)
: QObject(*(new QDeclarativeContextPrivate), parent)
{
    Q_D(QDeclarativeContext);
    QDeclarativeContext *parentContext = engine?engine->rootContext():0;
    d->parent = parentContext;
    d->engine = parentContext->engine();
    d->init();
}

/*!
    Create a new QDeclarativeContext with the given \a parentContext, and the
    QObject \a parent.
*/
QDeclarativeContext::QDeclarativeContext(QDeclarativeContext *parentContext, QObject *parent)
: QObject(*(new QDeclarativeContextPrivate), parent)
{
    Q_D(QDeclarativeContext);
    d->parent = parentContext;
    d->engine = parentContext->engine();
    d->init();
}

/*!
    \internal
*/
QDeclarativeContext::QDeclarativeContext(QDeclarativeContext *parentContext, QObject *parent, bool)
: QObject(*(new QDeclarativeContextPrivate), parent)
{
    Q_D(QDeclarativeContext);
    d->parent = parentContext;
    d->engine = parentContext->engine();
    d->isInternal = true;
    d->init();
}

/*!
    Destroys the QDeclarativeContext.

    Any expressions, or sub-contexts dependent on this context will be
    invalidated, but not destroyed (unless they are parented to the QDeclarativeContext
    object).
 */
QDeclarativeContext::~QDeclarativeContext()
{
    Q_D(QDeclarativeContext);
    if (d->parent) 
        d->parent->d_func()->childContexts.remove(this);

    for (QSet<QDeclarativeContext *>::ConstIterator iter = d->childContexts.begin();
            iter != d->childContexts.end();
            ++iter) {
        (*iter)->d_func()->invalidateEngines();
        (*iter)->d_func()->parent = 0;
    }

    QDeclarativeAbstractExpression *expression = d->expressions;
    while (expression) {
        QDeclarativeAbstractExpression *nextExpression = expression->m_nextExpression;

        expression->m_context = 0;
        expression->m_prevExpression = 0;
        expression->m_nextExpression = 0;

        expression = nextExpression;
    }

    while (d->contextObjects) {
        QDeclarativeDeclarativeData *co = d->contextObjects;
        d->contextObjects = d->contextObjects->nextContextObject;

        co->context = 0;
        co->nextContextObject = 0;
        co->prevContextObject = 0;
    }

    if (d->propertyNames)
        d->propertyNames->release();

    if (d->imports)
        d->imports->release();

    if (d->optimizedBindings)
        d->optimizedBindings->release();

    delete [] d->idValues;
}

void QDeclarativeContextPrivate::invalidateEngines()
{
    if (!engine)
        return;
    engine = 0;
    for (QSet<QDeclarativeContext *>::ConstIterator iter = childContexts.begin();
            iter != childContexts.end();
            ++iter) {
        (*iter)->d_func()->invalidateEngines();
    }
}

/* 
Refreshes all expressions that could possibly depend on this context.
Refreshing flushes all context-tree dependent caches in the expressions, and should occur every
time the context tree *structure* (not values) changes.
*/
void QDeclarativeContextPrivate::refreshExpressions()
{
    for (QSet<QDeclarativeContext *>::ConstIterator iter = childContexts.begin();
            iter != childContexts.end();
            ++iter) {
        (*iter)->d_func()->refreshExpressions();
    }

    QDeclarativeAbstractExpression *expression = expressions;
    while (expression) {
        expression->refresh();
        expression = expression->m_nextExpression;
    }
}

/*!
    Return the context's QDeclarativeEngine, or 0 if the context has no QDeclarativeEngine or the
    QDeclarativeEngine was destroyed.
*/
QDeclarativeEngine *QDeclarativeContext::engine() const
{
    Q_D(const QDeclarativeContext);
    return d->engine;
}

/*!
    Return the context's parent QDeclarativeContext, or 0 if this context has no
    parent or if the parent has been destroyed.
*/
QDeclarativeContext *QDeclarativeContext::parentContext() const
{
    Q_D(const QDeclarativeContext);
    return d->parent;
}

/*!
    Add \a defaultObject to this context.  The object will be added after
    any existing default objects.
*/
void QDeclarativeContext::addDefaultObject(QObject *defaultObject)
{
    Q_D(QDeclarativeContext);
    d->defaultObjects.prepend(defaultObject);
}

/*!
    Set a the \a value of the \a name property on this context.
*/
void QDeclarativeContext::setContextProperty(const QString &name, const QVariant &value)
{
    Q_D(QDeclarativeContext);
    if (d->notifyIndex == -1)
        d->notifyIndex = this->metaObject()->methodCount();

    if (d->engine) {
        bool ok;
        QObject *o = QDeclarativeEnginePrivate::get(d->engine)->toQObject(value, &ok);
        if (ok) {
            setContextProperty(name, o);
            return;
        }
    }

    if (!d->propertyNames) d->propertyNames = new QDeclarativeIntegerCache(d->engine);

    int idx = d->propertyNames->value(name);
    if (idx == -1) {
        d->propertyNames->add(name, d->idValueCount + d->propertyValues.count());
        d->propertyValues.append(value);

        d->refreshExpressions();
    } else {
        d->propertyValues[idx] = value;
        QMetaObject::activate(this, idx + d->notifyIndex, 0);
    }
}

void QDeclarativeContextPrivate::setIdProperty(int idx, QObject *obj)
{
    if (notifyIndex == -1) {
        Q_Q(QDeclarativeContext);
        notifyIndex = q->metaObject()->methodCount();
    }

    idValues[idx].priv = this;
    idValues[idx] = obj;
}

void QDeclarativeContextPrivate::setIdPropertyData(QDeclarativeIntegerCache *data)
{
    Q_ASSERT(!propertyNames);
    propertyNames = data;
    propertyNames->addref();

    idValueCount = data->count();
    idValues = new ContextGuard[idValueCount];
}

/*!
    Set the \a value of the \a name property on this context.

    QDeclarativeContext does \bold not take ownership of \a value.
*/
void QDeclarativeContext::setContextProperty(const QString &name, QObject *value)
{
    Q_D(QDeclarativeContext);
    if (d->notifyIndex == -1)
        d->notifyIndex = this->metaObject()->methodCount();

    if (!d->propertyNames) d->propertyNames = new QDeclarativeIntegerCache(d->engine);
    int idx = d->propertyNames->value(name);

    if (idx == -1) {
        d->propertyNames->add(name, d->idValueCount  + d->propertyValues.count());
        d->propertyValues.append(QVariant::fromValue(value));

        d->refreshExpressions();
    } else {
        d->propertyValues[idx] = QVariant::fromValue(value);
        QMetaObject::activate(this, idx + d->notifyIndex, 0);
    }
}

/*!
  Returns the value of the \a name property for this context
  as a QVariant.
 */
QVariant QDeclarativeContext::contextProperty(const QString &name) const
{
    Q_D(const QDeclarativeContext);
    QVariant value;
    int idx = -1;
    if (d->propertyNames)
        idx = d->propertyNames->value(name);

    if (idx == -1) {
        QByteArray utf8Name = name.toUtf8();
        for (int ii = d->defaultObjects.count() - 1; ii >= 0; --ii) {
            QObject *obj = d->defaultObjects.at(ii);
            QDeclarativePropertyCache::Data local;
            QDeclarativePropertyCache::Data *property = QDeclarativePropertyCache::property(d->engine, obj, name, local);

            if (property) {
                value = obj->metaObject()->property(property->coreIndex).read(obj);
                break;
            }
        }
        if (!value.isValid() && parentContext())
            value = parentContext()->contextProperty(name);
    } else {
        value = d->propertyValues[idx];
    }

    return value;
}

/*!
    Resolves the URL \a src relative to the URL of the
    containing component.

    \sa QDeclarativeEngine::baseUrl(), setBaseUrl()
*/
QUrl QDeclarativeContext::resolvedUrl(const QUrl &src)
{
    Q_D(QDeclarativeContext);
    QDeclarativeContext *ctxt = this;
    if (src.isRelative() && !src.isEmpty()) {
        if (ctxt) {
            while(ctxt) {
                if(ctxt->d_func()->url.isValid())
                    break;
                else
                    ctxt = ctxt->parentContext();
            }

            if (ctxt)
                return ctxt->d_func()->url.resolved(src);
            else if (d->engine)
                return d->engine->baseUrl().resolved(src);
        }
        return QUrl();
    } else {
        return src;
    }
}

/*!
    Explicitly sets the url resolvedUrl() will use for relative references to \a baseUrl.

    Calling this function will override the url of the containing
    component used by default.

    \sa resolvedUrl()
*/
void QDeclarativeContext::setBaseUrl(const QUrl &baseUrl)
{
    d_func()->url = baseUrl;
}

/*!
    Returns the base url of the component, or the containing component
    if none is set.
*/
QUrl QDeclarativeContext::baseUrl() const
{
    const QDeclarativeContext* p = this;
    while (p && p->d_func()->url.isEmpty()) {
        p = p->parentContext();
    }
    if (p)
        return p->d_func()->url;
    else
        return QUrl();
}

int QDeclarativeContextPrivate::context_count(QDeclarativeListProperty<QObject> *prop)
{
    QDeclarativeContext *context = static_cast<QDeclarativeContext*>(prop->object);
    QDeclarativeContextPrivate *d = QDeclarativeContextPrivate::get(context);
    int contextProperty = (int)(intptr_t)prop->data;

    if (d->propertyValues.at(contextProperty).userType() != qMetaTypeId<QList<QObject*> >()) {
        return 0;
    } else {
        return ((const QList<QObject> *)d->propertyValues.at(contextProperty).constData())->count();
    }
}

QObject *QDeclarativeContextPrivate::context_at(QDeclarativeListProperty<QObject> *prop, int index)
{
    QDeclarativeContext *context = static_cast<QDeclarativeContext*>(prop->object);
    QDeclarativeContextPrivate *d = QDeclarativeContextPrivate::get(context);
    int contextProperty = (int)(intptr_t)prop->data;

    if (d->propertyValues.at(contextProperty).userType() != qMetaTypeId<QList<QObject*> >()) {
        return 0;
    } else {
        return ((const QList<QObject*> *)d->propertyValues.at(contextProperty).constData())->at(index);
    }
}

QT_END_NAMESPACE