qdeclarativeexpression.cpp

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** This file is part of the QtDeclarative module of the Qt Toolkit.
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#include "qdeclarativeexpression.h"
#include "private/qdeclarativeexpression_p.h"

#include "private/qdeclarativeengine_p.h"
#include "private/qdeclarativecontext_p.h"
#include "private/qdeclarativerewrite_p.h"
#include "private/qdeclarativecompiler_p.h"
#include "private/qdeclarativeglobalscriptclass_p.h"

#include <QtCore/qdebug.h>
#include <QtScript/qscriptprogram.h>

#include <private/qscriptdeclarativeclass_p.h>

QT_BEGIN_NAMESPACE

bool QDeclarativeDelayedError::addError(QDeclarativeEnginePrivate *e)
{
    if (!e) return false;

    if (e->inProgressCreations == 0) return false; // Not in construction

    if (prevError) return true; // Already in error chain

    prevError = &e->erroredBindings;
    nextError = e->erroredBindings;
    e->erroredBindings = this;
    if (nextError) nextError->prevError = &nextError;

    return true;
}

QDeclarativeQtScriptExpression::QDeclarativeQtScriptExpression()
: dataRef(0), expressionFunctionMode(ExplicitContext), scopeObject(0), trackChange(false), 
  guardList(0), guardListLength(0), guardObject(0), guardObjectNotifyIndex(-1), deleted(0)
{
}

QDeclarativeQtScriptExpression::~QDeclarativeQtScriptExpression()
{
    if (guardList) { delete [] guardList; guardList = 0; }
    if (dataRef) dataRef->release();
    if (deleted) *deleted = true;
}

QDeclarativeExpressionPrivate::QDeclarativeExpressionPrivate()
: expressionFunctionValid(true), line(-1)
{
}

QDeclarativeExpressionPrivate::~QDeclarativeExpressionPrivate()
{
}

void QDeclarativeExpressionPrivate::init(QDeclarativeContextData *ctxt, const QString &expr, 
                                         QObject *me)
{
    expression = expr;

    QDeclarativeAbstractExpression::setContext(ctxt);
    scopeObject = me;
    expressionFunctionValid = false;
}

void QDeclarativeExpressionPrivate::init(QDeclarativeContextData *ctxt, const QScriptValue &func,
                                         QObject *me)
{
    expression = func.toString();

    QDeclarativeAbstractExpression::setContext(ctxt);
    scopeObject = me;

    expressionFunction = func;
    expressionFunctionMode = ExplicitContext;
    expressionFunctionValid = true;
}

void QDeclarativeExpressionPrivate::init(QDeclarativeContextData *ctxt, void *expr, 
                                         QDeclarativeRefCount *rc, 
                                         QObject *me, const QString &srcUrl, int lineNumber)
{
    url = srcUrl;
    line = lineNumber;

    if (dataRef) dataRef->release();
    dataRef = rc;
    if (dataRef) dataRef->addref();

    quint32 *exprData = (quint32 *)expr;
    QDeclarativeCompiledData *dd = (QDeclarativeCompiledData *)rc;

    expression = QString::fromRawData((QChar *)(exprData + 2), exprData[1]);

    int progIdx = *(exprData);
    bool isSharedProgram = progIdx & 0x80000000;
    progIdx &= 0x7FFFFFFF;

    QDeclarativeEngine *engine = ctxt->engine;
    QDeclarativeEnginePrivate *ep = QDeclarativeEnginePrivate::get(engine);
    QScriptEngine *scriptEngine = QDeclarativeEnginePrivate::getScriptEngine(engine);

    if (isSharedProgram) {

        if (!dd->cachedClosures.at(progIdx)) {
            QScriptContext *scriptContext = QScriptDeclarativeClass::pushCleanContext(scriptEngine);
            scriptContext->pushScope(ep->contextClass->newSharedContext());
            scriptContext->pushScope(ep->globalClass->staticGlobalObject());
            dd->cachedClosures[progIdx] = new QScriptValue(scriptEngine->evaluate(expression, url, line));
            scriptEngine->popContext();
        }

        expressionFunction = *dd->cachedClosures.at(progIdx);
        expressionFunctionMode = SharedContext;
        expressionFunctionValid = true;

    } else {

        if (!dd->cachedPrograms.at(progIdx)) {
            dd->cachedPrograms[progIdx] = new QScriptProgram(expression, url, line);
        }

        expressionFunction = evalInObjectScope(ctxt, me, *dd->cachedPrograms.at(progIdx), 
                                                     &expressionContext);

        expressionFunctionMode = ExplicitContext;
        expressionFunctionValid = true;
    }

    QDeclarativeAbstractExpression::setContext(ctxt);
    scopeObject = me;
}

QScriptValue QDeclarativeExpressionPrivate::evalInObjectScope(QDeclarativeContextData *context, QObject *object, 
                                                              const QString &program, const QString &fileName,
                                                              int lineNumber, QScriptValue *contextObject)
{
    QDeclarativeEnginePrivate *ep = QDeclarativeEnginePrivate::get(context->engine);
    QScriptContext *scriptContext = QScriptDeclarativeClass::pushCleanContext(&ep->scriptEngine);
    if (contextObject) {
        *contextObject = ep->contextClass->newContext(context, object);
        scriptContext->pushScope(*contextObject);
    } else {
        scriptContext->pushScope(ep->contextClass->newContext(context, object));
    }
    scriptContext->pushScope(ep->globalClass->staticGlobalObject());
    QScriptValue rv = ep->scriptEngine.evaluate(program, fileName, lineNumber);
    ep->scriptEngine.popContext();
    return rv;
}

QScriptValue QDeclarativeExpressionPrivate::evalInObjectScope(QDeclarativeContextData *context, QObject *object, 
                                                              const QScriptProgram &program, 
                                                              QScriptValue *contextObject)
{
    QDeclarativeEnginePrivate *ep = QDeclarativeEnginePrivate::get(context->engine);
    QScriptContext *scriptContext = QScriptDeclarativeClass::pushCleanContext(&ep->scriptEngine);
    if (contextObject) {
        *contextObject = ep->contextClass->newContext(context, object);
        scriptContext->pushScope(*contextObject);
    } else {
        scriptContext->pushScope(ep->contextClass->newContext(context, object));
    }
    scriptContext->pushScope(ep->globalClass->staticGlobalObject());
    QScriptValue rv = ep->scriptEngine.evaluate(program);
    ep->scriptEngine.popContext();
    return rv;
}

static int QDeclarativeExpression_notifyIdx = -1;

QDeclarativeExpression::QDeclarativeExpression()
: QObject(*new QDeclarativeExpressionPrivate, 0)
{
    Q_D(QDeclarativeExpression);

    if (QDeclarativeExpression_notifyIdx == -1) 
        QDeclarativeExpression_notifyIdx = QDeclarativeExpression::staticMetaObject.indexOfMethod("_q_notify()");
    d->setNotifyObject(this, QDeclarativeExpression_notifyIdx);
}

QDeclarativeExpression::QDeclarativeExpression(QDeclarativeContextData *ctxt, void *expr,
                                               QDeclarativeRefCount *rc, QObject *me, 
                                               const QString &url, int lineNumber,
                                               QDeclarativeExpressionPrivate &dd)
: QObject(dd, 0)
{
    Q_D(QDeclarativeExpression);
    d->init(ctxt, expr, rc, me, url, lineNumber);

    if (QDeclarativeExpression_notifyIdx == -1) 
        QDeclarativeExpression_notifyIdx = QDeclarativeExpression::staticMetaObject.indexOfMethod("_q_notify()");
    d->setNotifyObject(this, QDeclarativeExpression_notifyIdx);
}

QDeclarativeExpression::QDeclarativeExpression(QDeclarativeContext *ctxt,
                                               QObject *scope,
                                               const QString &expression,
                                               QObject *parent)
: QObject(*new QDeclarativeExpressionPrivate, parent)
{
    Q_D(QDeclarativeExpression);
    d->init(QDeclarativeContextData::get(ctxt), expression, scope);

    if (QDeclarativeExpression_notifyIdx == -1) 
        QDeclarativeExpression_notifyIdx = QDeclarativeExpression::staticMetaObject.indexOfMethod("_q_notify()");
    d->setNotifyObject(this, QDeclarativeExpression_notifyIdx);
}

QDeclarativeExpression::QDeclarativeExpression(QDeclarativeContextData *ctxt, QObject *scope,
                                               const QString &expression)
: QObject(*new QDeclarativeExpressionPrivate, 0)
{
    Q_D(QDeclarativeExpression);
    d->init(ctxt, expression, scope);

    if (QDeclarativeExpression_notifyIdx == -1) 
        QDeclarativeExpression_notifyIdx = QDeclarativeExpression::staticMetaObject.indexOfMethod("_q_notify()");
    d->setNotifyObject(this, QDeclarativeExpression_notifyIdx);
}

QDeclarativeExpression::QDeclarativeExpression(QDeclarativeContextData *ctxt, QObject *scope,
                                               const QString &expression, QDeclarativeExpressionPrivate &dd)
: QObject(dd, 0)
{
    Q_D(QDeclarativeExpression);
    d->init(ctxt, expression, scope);

    if (QDeclarativeExpression_notifyIdx == -1) 
        QDeclarativeExpression_notifyIdx = QDeclarativeExpression::staticMetaObject.indexOfMethod("_q_notify()");
    d->setNotifyObject(this, QDeclarativeExpression_notifyIdx);
}

QDeclarativeExpression::QDeclarativeExpression(QDeclarativeContextData *ctxt, QObject *scope, const QScriptValue &func,
                       QDeclarativeExpressionPrivate &dd)
: QObject(dd, 0)
{
    Q_D(QDeclarativeExpression);
    d->init(ctxt, func, scope);

    if (QDeclarativeExpression_notifyIdx == -1)
        QDeclarativeExpression_notifyIdx = QDeclarativeExpression::staticMetaObject.indexOfMethod("_q_notify()");
    d->setNotifyObject(this, QDeclarativeExpression_notifyIdx);
}

QDeclarativeExpression::~QDeclarativeExpression()
{
}

QDeclarativeEngine *QDeclarativeExpression::engine() const
{
    Q_D(const QDeclarativeExpression);
    return d->context()?d->context()->engine:0;
}

QDeclarativeContext *QDeclarativeExpression::context() const
{
    Q_D(const QDeclarativeExpression);
    QDeclarativeContextData *data = d->context();
    return data?data->asQDeclarativeContext():0;
}

QString QDeclarativeExpression::expression() const
{
    Q_D(const QDeclarativeExpression);
    return d->expression;
}

void QDeclarativeExpression::setExpression(const QString &expression)
{
    Q_D(QDeclarativeExpression);

    d->resetNotifyOnChange();
    d->expression = expression;
    d->expressionFunctionValid = false;
    d->expressionFunction = QScriptValue();
}

void QDeclarativeExpressionPrivate::exceptionToError(QScriptEngine *scriptEngine, 
                                            QDeclarativeError &error)
{
    if (scriptEngine->hasUncaughtException() && 
        scriptEngine->uncaughtException().isError()) {

        QString fileName;
        int lineNumber = scriptEngine->uncaughtExceptionLineNumber();

        QScriptValue exception = scriptEngine->uncaughtException();
        QLatin1String fileNameProp("fileName");

        if (!exception.property(fileNameProp).toString().isEmpty()){
            fileName = exception.property(fileNameProp).toString();
        } else {
            fileName = QLatin1String("<Unknown File>");
        }

        error.setUrl(QUrl(fileName));
        error.setLine(lineNumber);
        error.setColumn(-1);
        error.setDescription(exception.toString());
    } else {
        error = QDeclarativeError();
    }
}

bool QDeclarativeQtScriptExpression::notifyOnValueChange() const
{
    return trackChange;
}

void QDeclarativeQtScriptExpression::setNotifyOnValueChange(bool notify)
{
    trackChange = notify;
    if (!notify && guardList) 
        clearGuards();
}

void QDeclarativeQtScriptExpression::resetNotifyOnChange()
{
    clearGuards();
}

void QDeclarativeQtScriptExpression::setNotifyObject(QObject *object, int notifyIndex)
{
    if (guardList) clearGuards();

    if (!object || notifyIndex == -1) {
        guardObject = 0;
        notifyIndex = -1;
    } else {
        guardObject = object;
        guardObjectNotifyIndex = notifyIndex;

    }
}

void QDeclarativeQtScriptExpression::setEvaluateFlags(EvaluateFlags flags)
{
    evalFlags = flags;
}

QDeclarativeQtScriptExpression::EvaluateFlags QDeclarativeQtScriptExpression::evaluateFlags() const
{
    return evalFlags;
}

QScriptValue QDeclarativeQtScriptExpression::scriptValue(QObject *secondaryScope, bool *isUndefined)
{
    Q_ASSERT(context() && context()->engine);
    Q_ASSERT(!trackChange || (guardObject && guardObjectNotifyIndex != -1));

    if (!expressionFunction.isValid()) {
        if (isUndefined) *isUndefined = true;
        return QScriptValue();
    }

    DeleteWatcher watcher(this);

    QDeclarativeEnginePrivate *ep = QDeclarativeEnginePrivate::get(context()->engine);

    bool lastCaptureProperties = ep->captureProperties;
    QPODVector<QDeclarativeEnginePrivate::CapturedProperty, 16> lastCapturedProperties;
    ep->captureProperties = trackChange;
    ep->capturedProperties.copyAndClear(lastCapturedProperties);

    QScriptValue value = eval(secondaryScope, isUndefined);

    if (!watcher.wasDeleted() && trackChange) {
        if (ep->capturedProperties.count() == 0) {

            if (guardList) clearGuards();

        } else {

            updateGuards(ep->capturedProperties);

        }
    }

    lastCapturedProperties.copyAndClear(ep->capturedProperties);
    ep->captureProperties = lastCaptureProperties;

    return value;
}

QScriptValue QDeclarativeQtScriptExpression::eval(QObject *secondaryScope, bool *isUndefined)
{
    Q_ASSERT(context() && context()->engine);

    DeleteWatcher watcher(this);

    QDeclarativeEngine *engine = context()->engine;
    QDeclarativeEnginePrivate *ep = QDeclarativeEnginePrivate::get(engine);

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

    QDeclarativeContextData *oldSharedContext = 0;
    QObject *oldSharedScope = 0;
    QObject *oldOverride = 0;
    bool isShared = (expressionFunctionMode == SharedContext);

    if (isShared) {
        oldSharedContext = ep->sharedContext;
        oldSharedScope = ep->sharedScope;
        ep->sharedContext = context();
        ep->sharedScope = scopeObject;
    } else {
        oldOverride = ep->contextClass->setOverrideObject(expressionContext, secondaryScope);
    }

    QScriptValue thisObject;
    if (evalFlags & RequiresThisObject)
        thisObject = ep->objectClass->newQObject(scopeObject);
    QScriptValue svalue = expressionFunction.call(thisObject); // This could cause this c++ object to be deleted

    if (isShared) {
        ep->sharedContext = oldSharedContext;
        ep->sharedScope = oldSharedScope;
    } else if (!watcher.wasDeleted()) {
        ep->contextClass->setOverrideObject(expressionContext, oldOverride);
    }

    if (isUndefined)
        *isUndefined = svalue.isUndefined() || scriptEngine->hasUncaughtException();

    // Handle exception
    if (scriptEngine->hasUncaughtException()) {
        if (!watcher.wasDeleted()) 
           QDeclarativeExpressionPrivate::exceptionToError(scriptEngine, error);

       scriptEngine->clearExceptions();
       return QScriptValue();
    } else {
        if (!watcher.wasDeleted())
            error = QDeclarativeError();

        return svalue;
    }
}

void QDeclarativeQtScriptExpression::updateGuards(const QPODVector<QDeclarativeEnginePrivate::CapturedProperty, 16> &properties)
{
    Q_ASSERT(guardObject);
    Q_ASSERT(guardObjectNotifyIndex != -1);

    if (properties.count() != guardListLength) {
        QDeclarativeNotifierEndpoint *newGuardList = new QDeclarativeNotifierEndpoint[properties.count()];

        for (int ii = 0; ii < qMin(guardListLength, properties.count()); ++ii) 
           guardList[ii].copyAndClear(newGuardList[ii]);

        delete [] guardList;
        guardList = newGuardList;
        guardListLength = properties.count();
    }

    bool outputWarningHeader = false;
    bool noChanges = true;
    for (int ii = 0; ii < properties.count(); ++ii) {
        QDeclarativeNotifierEndpoint &guard = guardList[ii];
        const QDeclarativeEnginePrivate::CapturedProperty &property = properties.at(ii);

        guard.target = guardObject;
        guard.targetMethod = guardObjectNotifyIndex;

        if (property.notifier != 0) {

            if (!noChanges && guard.isConnected(property.notifier)) {
                // Nothing to do

            } else {
                noChanges = false;

                bool existing = false;
                for (int jj = 0; !existing && jj < ii; ++jj) 
                    if (guardList[jj].isConnected(property.notifier)) 
                        existing = true;

                if (existing) {
                    // duplicate
                    guard.disconnect();
                } else {
                    guard.connect(property.notifier);
                }
            }


        } else if (property.notifyIndex != -1) {

            if (!noChanges && guard.isConnected(property.object, property.notifyIndex)) {
                // Nothing to do

            } else {
                noChanges = false;

                bool existing = false;
                for (int jj = 0; !existing && jj < ii; ++jj) 
                    if (guardList[jj].isConnected(property.object, property.notifyIndex)) 
                        existing = true;

                if (existing) {
                    // duplicate
                    guard.disconnect();
                } else {
                    guard.connect(property.object, property.notifyIndex);
                }
            }

        } else {
            if (!outputWarningHeader) {
                outputWarningHeader = true;
                qWarning() << "QDeclarativeExpression: Expression" << expression
                           << "depends on non-NOTIFYable properties:";
            }

            const QMetaObject *metaObj = property.object->metaObject();
            QMetaProperty metaProp = metaObj->property(property.coreIndex);

            qWarning().nospace() << "    " << metaObj->className() << "::" << metaProp.name();
        }
    }
}

QScriptValue QDeclarativeExpressionPrivate::scriptValue(QObject *secondaryScope, bool *isUndefined)
{
    if (!expressionFunctionValid) {
        QDeclarativeEngine *engine = context()->engine;
        QDeclarativeEnginePrivate *ep = QDeclarativeEnginePrivate::get(engine);

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

        QScriptContext *scriptContext = QScriptDeclarativeClass::pushCleanContext(scriptEngine);
        expressionContext = ep->contextClass->newContext(context(), scopeObject);
        scriptContext->pushScope(expressionContext);
        scriptContext->pushScope(ep->globalClass->staticGlobalObject());

        QDeclarativeRewrite::RewriteBinding rewriteBinding;
        rewriteBinding.setName(name);
        bool ok = true;
        const QString code = rewriteBinding(expression, &ok);
        if (ok) 
            expressionFunction = scriptEngine->evaluate(code, url, line);

        scriptEngine->popContext();
        expressionFunctionMode = ExplicitContext;
        expressionFunctionValid = true;
    }

    return QDeclarativeQtScriptExpression::scriptValue(secondaryScope, isUndefined);
}

QVariant QDeclarativeExpressionPrivate::value(QObject *secondaryScope, bool *isUndefined)
{
    Q_Q(QDeclarativeExpression);

    if (!context() || !context()->isValid()) {
        qWarning("QDeclarativeExpression: Attempted to evaluate an expression in an invalid context");
        return QVariant();
    }

    QDeclarativeEnginePrivate *ep = QDeclarativeEnginePrivate::get(q->engine());

    return ep->scriptValueToVariant(scriptValue(secondaryScope, isUndefined), qMetaTypeId<QList<QObject*> >());
}

QVariant QDeclarativeExpression::evaluate(bool *valueIsUndefined)
{
    Q_D(QDeclarativeExpression);
    return d->value(0, valueIsUndefined);
}

bool QDeclarativeExpression::notifyOnValueChanged() const
{
    Q_D(const QDeclarativeExpression);
    return d->notifyOnValueChange();
}

void QDeclarativeExpression::setNotifyOnValueChanged(bool notifyOnChange)
{
    Q_D(QDeclarativeExpression);
    d->setNotifyOnValueChange(notifyOnChange);
}

QString QDeclarativeExpression::sourceFile() const
{
    Q_D(const QDeclarativeExpression);
    return d->url;
}

int QDeclarativeExpression::lineNumber() const
{
    Q_D(const QDeclarativeExpression);
    return d->line;
}

void QDeclarativeExpression::setSourceLocation(const QString &url, int line)
{
    Q_D(QDeclarativeExpression);
    d->url = url;
    d->line = line;
}

QObject *QDeclarativeExpression::scopeObject() const
{
    Q_D(const QDeclarativeExpression);
    return d->scopeObject;
}

bool QDeclarativeExpression::hasError() const
{
    Q_D(const QDeclarativeExpression);
    return d->error.isValid();
}

void QDeclarativeExpression::clearError()
{
    Q_D(QDeclarativeExpression);
    d->error = QDeclarativeError();
}

QDeclarativeError QDeclarativeExpression::error() const
{
    Q_D(const QDeclarativeExpression);
    return d->error;
}

void QDeclarativeExpressionPrivate::_q_notify()
{
    emitValueChanged();
}

void QDeclarativeQtScriptExpression::clearGuards()
{
    delete [] guardList; 
    guardList = 0; 
    guardListLength = 0;
}

void QDeclarativeExpressionPrivate::emitValueChanged()
{
    Q_Q(QDeclarativeExpression);
    emit q->valueChanged();
}

QDeclarativeAbstractExpression::QDeclarativeAbstractExpression()
: m_context(0), m_prevExpression(0), m_nextExpression(0)
{
}

QDeclarativeAbstractExpression::~QDeclarativeAbstractExpression()
{
    if (m_prevExpression) {
        *m_prevExpression = m_nextExpression;
        if (m_nextExpression) 
            m_nextExpression->m_prevExpression = m_prevExpression;
    }
}

QDeclarativeContextData *QDeclarativeAbstractExpression::context() const
{
    return m_context;
}

void QDeclarativeAbstractExpression::setContext(QDeclarativeContextData *context)
{
    if (m_prevExpression) {
        *m_prevExpression = m_nextExpression;
        if (m_nextExpression) 
            m_nextExpression->m_prevExpression = m_prevExpression;
        m_prevExpression = 0;
        m_nextExpression = 0;
    }

    m_context = context;

    if (m_context) {
        m_nextExpression = m_context->expressions;
        if (m_nextExpression) 
            m_nextExpression->m_prevExpression = &m_nextExpression;
        m_prevExpression = &context->expressions;
        m_context->expressions = this;
    }
}

void QDeclarativeAbstractExpression::refresh()
{
}

bool QDeclarativeAbstractExpression::isValid() const
{
    return m_context != 0;
}

QT_END_NAMESPACE

#include <moc_qdeclarativeexpression.cpp>