src/ecma/kjs_scriptable.cpp

/* This file is part of the KDE project
   Copyright (C) 2010 Maksim Orlovich <maksim@kde.org>

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.

   This library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public License
   along with this library; see the file COPYING.LIB.  If not, write to
   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
   Boston, MA 02110-1301, USA.
*/

#include "kjs_scriptable.h"
#include "kjs_binding.h"
#include "kjs_proxy.h"
#include "kjs_dom.h"
#include "khtmlpart_p.h"

namespace KJS
{

static QVariant scriptableNull()
{
    return QVariant::fromValue(ScriptableExtension::Null());
}

static bool isException(const QVariant &v)
{
    return v.canConvert<ScriptableExtension::Exception>();
}

static bool isFuncRef(const QVariant &v)
{
    return v.canConvert<ScriptableExtension::FunctionRef>();
}

static bool isForeignObject(const QVariant &v)
{
    return v.canConvert<ScriptableExtension::Object>();
}

QVariant exception(const char *msg)
{
    qCWarning(KHTML_LOG) << msg;
    return QVariant::fromValue(ScriptableExtension::Exception(QString::fromLatin1(msg)));
}

//------------------------------------------------------------------------------

// will return with owner = 0 on failure.
static ScriptableExtension::Object grabRoot(ScriptableExtension *ext)
{
    ScriptableExtension::Object o;

    if (!ext) {
        return o;
    }

    // Grab root, make sure it's an actual object.
    QVariant root = ext->rootObject();
    if (!isForeignObject(root)) {
        // Might still need to release it if it's a function
        ScriptableExtension::releaseValue(root);

        return o;
    }

    o = root.value<ScriptableExtension::Object>();
    return o;
}

// a couple helpers for client code.
bool pluginRootGet(ExecState *exec, ScriptableExtension *ext, const KJS::Identifier &i, PropertySlot &slot)
{
    ScriptableExtension::Object rootObj = grabRoot(ext);
    if (!rootObj.owner) {
        return false;
    }

    QVariant v = rootObj.owner->get(nullptr /* ### we don't expect leaves to check credentials*/,
                                    rootObj.objId, i.qstring());

    bool ok = false;
    if (!isException(v)) {
        getImmediateValueSlot(nullptr, ScriptableOperations::importValue(exec, v, true), slot);
        ok = true;
    }

    rootObj.owner->release(rootObj.objId);
    return ok;
}

bool pluginRootPut(ExecState * /*exec*/, ScriptableExtension *ext, const KJS::Identifier &i, JSValue *v)
{
    ScriptableExtension::Object rootObj = grabRoot(ext);
    if (!rootObj.owner) {
        return false;
    }

    QVariant qv = ScriptableOperations::exportValue(v, true);
    bool ok = rootObj.owner->put(nullptr, rootObj.objId, i.qstring(), qv);
    ScriptableExtension::releaseValue(qv);

    rootObj.owner->release(rootObj.objId);
    return ok;
}

//------------------------------------------------------------------------------
// KJS peer wrapping external objects

const ClassInfo WrapScriptableObject::info = { " WrapScriptableObject", nullptr, nullptr, nullptr };

WrapScriptableObject::WrapScriptableObject(ExecState * /*exec*/, Type t,
        ScriptableExtension *owner, quint64 objId,
        const QString &field):
    objExtension(owner), objId(objId), field(field), type(t), refsByUs(1), tableKey(owner)
{
    owner->acquire(objId);
}

WrapScriptableObject::~WrapScriptableObject()
{
    if (ScriptableExtension *o = objExtension.data()) {
        for (int r = 0; r < refsByUs; ++r) {
            o->release(objId);
        }
    }

    ScriptableExtension::Object obj(tableKey, objId);
    if (type == Object) {
        ScriptableOperations::importedObjects()->remove(obj);
    } else {
        ScriptableOperations::importedFunctions()->remove(ScriptableExtension::FunctionRef(obj, field));
    }
}

void WrapScriptableObject::reportRef()
{
    ++refsByUs;
}

QVariant WrapScriptableObject::doGet(ExecState *exec, const ScriptableExtension::Object &o,
                                     const QString &field, bool *ok)
{
    *ok = false;

    if (!o.owner) { // such as when was constructed from null .data();
        return QVariant();
    }

    QVariant v = o.owner->get(principal(exec), o.objId, field);

    if (!isException(v)) {
        *ok = true;
    }
    return v;
}

ScriptableExtension::Object WrapScriptableObject::resolveReferences(
    ExecState *exec,
    const ScriptableExtension::FunctionRef &f,
    bool *ok)
{
    QVariant v = doGet(exec, f.base, f.field, ok);
    if (*ok) {
        // See what sort of type we got.
        if (isForeignObject(v)) {
            return v.value<ScriptableExtension::Object>();
        } else if (isFuncRef(v)) {
            return resolveReferences(exec, v.value<ScriptableExtension::FunctionRef>(), ok);
        } else {
            // We got a primitive. We don't care for those.
            *ok = false;
        }
    }
    return ScriptableExtension::Object();
}

ScriptableExtension::Object WrapScriptableObject::resolveAnyReferences(ExecState *exec, bool *ok)
{
    ScriptableExtension::Object obj(objExtension.data(), objId);

    if (type == FunctionRef) {
        obj = resolveReferences(exec, ScriptableExtension::FunctionRef(obj, field), ok);
    }

    if (!obj.owner) {
        *ok = false;
    }

    return obj;
}

bool WrapScriptableObject::getOwnPropertySlot(ExecState *exec, const Identifier &i,
        PropertySlot &slot)
{
    bool ok;
    ScriptableExtension::Object actualObj = resolveAnyReferences(exec, &ok);

    if (!ok) {
        return false;
    }

    QVariant v = doGet(exec, actualObj, i.qstring(), &ok);

    if (!ok) {
        return false;
    }

    return getImmediateValueSlot(this, ScriptableOperations::importValue(exec, v, true), slot);
}

void WrapScriptableObject::put(ExecState *exec, const Identifier &i, JSValue *value, int)
{
    // ### Do we swallow failure, or what?
    bool ok;
    ScriptableExtension::Object actualObj = resolveAnyReferences(exec, &ok);

    if (!ok) {
        return;
    }

    QVariant sv = ScriptableOperations::exportValue(value, true);
    actualObj.owner->put(principal(exec), actualObj.objId, i.qstring(), sv);
    ScriptableExtension::releaseValue(sv);
}

bool WrapScriptableObject::deleteProperty(ExecState *exec, const Identifier &i)
{
    bool ok;
    ScriptableExtension::Object actualObj = resolveAnyReferences(exec, &ok);

    if (!ok) {
        return false;
    }

    return actualObj.owner->removeProperty(principal(exec),
                                           actualObj.objId, i.qstring());
}

ScriptableExtension::ArgList WrapScriptableObject::exportArgs(const List &l)
{
    ScriptableExtension::ArgList ol;
    for (int p = 0; p < l.size(); ++p) {
        ol.append(ScriptableOperations::exportValue(l.at(p), true));
    }
    return ol;
}

void WrapScriptableObject::releaseArgs(ScriptableExtension::ArgList &a)
{
    for (int p = 0; p < a.size(); ++p) {
        ScriptableOperations::releaseValue(a[p]);
    }
}

JSValue *WrapScriptableObject::callAsFunction(ExecState *exec, JSObject */*thisObj*/, const List &args)
{
    QVariant res;

    if (ScriptableExtension *base = objExtension.data()) {
        ScriptableExtension::ArgList sargs = exportArgs(args);
        if (type == Object) {
            res = base->callAsFunction(principal(exec), objId, sargs);
        } else {
            res = base->callFunctionReference(principal(exec), objId, field, sargs);
        }
        releaseArgs(sargs);
    }

    // Problem. Throw an exception.
    if (!res.isValid() || isException(res)) {
        return throwError(exec, GeneralError, "Call to plugin function failed");
    } else {
        return ScriptableOperations::importValue(exec, res, true);
    }
}

JSObject *WrapScriptableObject::construct(ExecState *exec, const List &args)
{
    QVariant res;

    bool ok;
    ScriptableExtension::Object actualObj = resolveAnyReferences(exec, &ok);
    if (ok) {
        ScriptableExtension::ArgList sargs = exportArgs(args);
        res = actualObj.owner->callAsConstructor(principal(exec), actualObj.objId,
                sargs);
        releaseArgs(sargs);
    }

    if (!res.isValid() || isException(res)) {
        return throwError(exec, GeneralError, "Call to plugin ctor failed");
    } else {
        JSValue *v = ScriptableOperations::importValue(exec, res, true);
        return v->toObject(exec);
    }
}

void WrapScriptableObject::getOwnPropertyNames(ExecState *exec, PropertyNameArray &a, PropertyMap::PropertyMode mode)
{
    JSObject::getOwnPropertyNames(exec, a, mode);

    bool ok;
    ScriptableExtension::Object actualObj = resolveAnyReferences(exec, &ok);
    if (ok) {
        QStringList out;
        if (actualObj.owner->enumerateProperties(principal(exec), actualObj.objId, &out)) {
            foreach (const QString &s, out) {
                a.add(Identifier(s));
            }
        }
    }
}

UString WrapScriptableObject::toString(ExecState *) const
{
    QString iface;
    if (ScriptableExtension *se = objExtension.data()) {
        iface = QString::fromLatin1(se->metaObject()->className());
    } else {
        iface = QString::fromLatin1("detached");
    }

    if (type == FunctionRef) {
        return QString(QLatin1String("[function ImportedScriptable:") + iface + QLatin1Char('/') + field + QLatin1Char(']'));
    } else {
        return QString(QLatin1String("[object ImportedScriptable:") + iface + QLatin1Char(']'));
    }
}

ScriptableExtension *WrapScriptableObject::principal(ExecState *exec)
{
    KJS::ScriptInterpreter *si = static_cast<KJS::ScriptInterpreter *>(exec->dynamicInterpreter());
    KParts::ReadOnlyPart   *part = si->part();
    if (!part) {
        return nullptr;
    }

    return ScriptableExtension::childObject(part);
}

//-----------------------------------------------------------------------------
// conversion stuff

/**
   SECURITY: For the conversion helpers, it is assumed that 'exec' corresponds
   to the appropriate principal.
*/

JSObject *ScriptableOperations::importObject(ExecState *exec, const QVariant &v, bool alreadyRefd)
{
    ScriptableExtension::Object obj = v.value<ScriptableExtension::Object>();
    if (JSObject *our = tryGetNativeObject(obj)) {
        return our;
    } else {
        // Create a wrapper, and register the import, this is just for
        // hashconsing.
        if (WrapScriptableObject *old = importedObjects()->value(obj)) {
            if (alreadyRefd) {
                old->reportRef();
            }
            return old;
        } else {
            WrapScriptableObject *wrap =
                new WrapScriptableObject(exec, WrapScriptableObject::Object,
                                         obj.owner, obj.objId);
            importedObjects()->insert(obj, wrap);
            if (alreadyRefd) {
                wrap->reportRef();
            }
            return wrap;
        }
    }
}

// Note: this is used to convert a full function ref to a value,
// which loses the this-binding in the native case.  We do keep the pair in the
// external case, inside the wrapper,  since the method might not have an own
// name, and we'd like to be able to refer to it.
JSValue *ScriptableOperations::importFunctionRef(ExecState *exec, const QVariant &v, bool /*alreadyRefd*/)
{
    ScriptableExtension::FunctionRef fr = v.value<ScriptableExtension::FunctionRef>();

    if (JSObject *base = tryGetNativeObject(fr.base)) {
        return base->get(exec, Identifier(fr.field));
    } else {
        if (WrapScriptableObject *old = importedFunctions()->value(fr)) {
            return old;
        } else {
            WrapScriptableObject *wrap =
                new WrapScriptableObject(exec, WrapScriptableObject::FunctionRef,
                                         fr.base.owner, fr.base.objId, fr.field);
            importedFunctions()->insert(fr, wrap);
            return wrap;
        }
    }
}

JSValue *ScriptableOperations::importValue(ExecState *exec, const QVariant &v, bool alreadyRefd)
{
    if (v.canConvert<ScriptableExtension::FunctionRef>()) {
        return importFunctionRef(exec, v, alreadyRefd);
    }
    if (v.canConvert<ScriptableExtension::Object>()) {
        return importObject(exec, v, alreadyRefd);
    }
    if (v.canConvert<ScriptableExtension::Null>()) {
        return jsNull();
    }
    if (v.canConvert<ScriptableExtension::Undefined>()) {
        return jsUndefined();
    }
    if (v.type() == QVariant::Bool) {
        return jsBoolean(v.toBool());
    }
    if (v.type() == QVariant::String) {
        return jsString(v.toString());
    }
    if (v.canConvert<double>()) {
        return jsNumber(v.toDouble());
    }
    qCWarning(KHTML_LOG) << "conversion from " << v << "failed";
    return jsNull();
}

List ScriptableOperations::importArgs(ExecState *exec, const ArgList &args)
{
    // Args are not pre-ref'd for us..
    List out;
    for (int i = 0; i < args.size(); ++i) {
        out.append(importValue(exec, args[i], false));
    }
    return out;
}

ScriptableExtension::Object ScriptableOperations::exportNativeObject(JSObject *o, bool preRef)
{
    assert(!o->inherits(&WrapScriptableObject::info));
    // We're exporting our own. Add to export table if needed.
    // Use the pointer as an ID.
    if (!exportedObjects()->contains(o)) {
        exportedObjects()->insert(o, 0);
    }
    if (preRef) {
        ++(*exportedObjects())[o];
    }

    return ScriptableExtension::Object(ScriptableOperations::self(),
                                       reinterpret_cast<quint64>(o));
}

QVariant ScriptableOperations::exportObject(JSObject *o, bool preRef)
{
    // XSS checks are done at get time, so if we have a value here, we can
    // export it.
    if (o->inherits(&WrapScriptableObject::info)) {
        // Re-exporting external one. That's easy.
        WrapScriptableObject *wo = static_cast<WrapScriptableObject *>(o);
        if (ScriptableExtension *owner = wo->objExtension.data()) {
            QVariant v = QVariant::fromValue(ScriptableExtension::Object(owner, wo->objId));
            if (preRef) {
                acquireValue(v);
            }
            return v;
        } else {
            qCWarning(KHTML_LOG) << "export of an object of a destroyed extension. Returning null";
            return scriptableNull();
        }
    } else {
        return QVariant::fromValue(exportNativeObject(o, preRef));
    }
}

QVariant ScriptableOperations::exportFuncRef(JSObject *base, const QString &field, bool preRef)
{
    ScriptableExtension::Object exportBase = exportNativeObject(base, preRef);
    return QVariant::fromValue(ScriptableExtension::FunctionRef(exportBase, field));
}

QVariant ScriptableOperations::exportValue(JSValue *v, bool preRef)
{
    switch (v->type()) {
    case NumberType:
        return QVariant::fromValue(v->getNumber());
    case BooleanType:
        return QVariant::fromValue(v->getBoolean());
    case NullType:
        return QVariant::fromValue(ScriptableExtension::Null());
    case StringType:
        return QVariant::fromValue(v->getString().qstring());
    case ObjectType:
        return exportObject(v->getObject(), preRef);
    case UndefinedType:
    default:
        return QVariant::fromValue(ScriptableExtension::Undefined());
    }
}

//-----------------------------------------------------------------------------
// operations
QHash<JSObject *, int> *ScriptableOperations::s_exportedObjects = nullptr;
QHash<ScriptableExtension::Object, WrapScriptableObject *> *ScriptableOperations::s_importedObjects   = nullptr;
QHash<ScriptableExtension::FunctionRef, WrapScriptableObject *> *ScriptableOperations::s_importedFunctions = nullptr;
ScriptableOperations *ScriptableOperations::s_instance = nullptr;

QHash<ScriptableExtension::Object, WrapScriptableObject *> *ScriptableOperations::importedObjects()
{
    if (!s_importedObjects) {
        s_importedObjects = new QHash<Object, WrapScriptableObject *>;
    }
    return s_importedObjects;
}

QHash<ScriptableExtension::FunctionRef, WrapScriptableObject *> *ScriptableOperations::importedFunctions()
{
    if (!s_importedFunctions) {
        s_importedFunctions = new QHash<FunctionRef, WrapScriptableObject *>();
    }
    return s_importedFunctions;
}

// A little helper for marking exportedObjects. We need this since we have
// an unclear runtime with respect to interpreter.
class ScriptableOperationsMarker: public JSObject
{
public:
    void mark() override
    {
        JSObject::mark();
        ScriptableOperations::self()->mark();
    }
};

QHash<JSObject *, int> *ScriptableOperations::exportedObjects()
{
    if (!s_exportedObjects) {
        s_exportedObjects = new QHash<JSObject *, int>;

        gcProtect(new ScriptableOperationsMarker());
    }
    return s_exportedObjects;
}

ScriptableOperations *ScriptableOperations::self()
{
    if (!s_instance) {
        s_instance = new ScriptableOperations;
    }
    return s_instance;
}

ScriptableOperations::ScriptableOperations(): ScriptableExtension(nullptr)
{}

ScriptableOperations::~ScriptableOperations()
{
    assert(false);
}

JSObject *ScriptableOperations::tryGetNativeObject(const Object &sObj)
{
    if (ScriptableOperations *o = qobject_cast<ScriptableOperations *>(sObj.owner)) {
        return o->objectForId(sObj.objId);
    } else {
        return nullptr;
    }
}

QVariant ScriptableOperations::handleReturn(ExecState *exec, JSValue *v)
{
    if (exec->hadException()) {
        JSValue *e = exec->exception();
        exec->clearException();

        QString msg = QLatin1String("KJS exception");

        if (JSObject *eo = e->getObject()) {
            JSValue *msgVal = eo->get(exec, exec->propertyNames().message);
            if (!msgVal->isUndefined()) {
                msg = msgVal->toString(exec).qstring();
            }

            // in case the get failed too.
            exec->clearException();
        }

        return QVariant::fromValue(ScriptableExtension::Exception(msg));
    }

    return exportValue(v, true);
}

QVariant ScriptableOperations::callAsFunction(ScriptableExtension *caller,
        quint64 objId, const ArgList &args)
{
    ExecState *exec = execStateForPrincipal(caller);
    if (!exec) {
        return exception("No scripting context or frame");
    }

    JSObject *fn = objectForId(objId);
    if (!fn || !fn->implementsCall()) {
        return exception("Call on a non-object or non-calleable");
    }

    JSValue *res = fn->callAsFunction(exec, exec->dynamicInterpreter()->globalObject(),
                                      importArgs(exec, args));
    return handleReturn(exec, res);
}

QVariant ScriptableOperations::callAsConstructor(ScriptableExtension *caller, quint64 objId, const ArgList &args)
{
    ExecState *exec = execStateForPrincipal(caller);
    if (!exec) {
        return exception("No scripting context or frame");
    }

    JSObject *fn = objectForId(objId);
    if (!fn || !fn->implementsConstruct()) {
        return exception("new on a non-constructor");
    }

    JSValue *res = fn->construct(exec, importArgs(exec, args));
    return handleReturn(exec, res);
}

QVariant ScriptableOperations::callFunctionReference(ScriptableExtension *caller,
        quint64 objId, const QString &f, const ArgList &args)
{
    ExecState *exec = execStateForPrincipal(caller);

    if (!exec) {
        return exception("No scripting context or frame");
    }

    JSObject *base = objectForId(objId);
    if (!base) {
        return exception("Call with an invalid base");
    }

    JSValue *kid = base->get(exec, Identifier(f));
    if (!kid->isObject() || exec->hadException() || !kid->getObject()->implementsCall()) {
        exec->clearException();
        return exception("Reference did not resolve to a function");
    }

    // Whee..
    JSValue *res = kid->getObject()->callAsFunction(exec, base, importArgs(exec, args));
    return handleReturn(exec, res);
}

bool ScriptableOperations::hasProperty(ScriptableExtension *caller, quint64 objId, const QString &propName)
{
    ExecState *exec = execStateForPrincipal(caller);
    if (!exec) {
        exception("No scripting context or frame");
        return false;
    }

    JSObject *o = objectForId(objId);
    if (!o) {
        exception("hasProperty on a non-object");
        return false;
    }

    return o->hasProperty(exec, Identifier(propName));
}

QVariant ScriptableOperations::get(ScriptableExtension *caller, quint64 objId, const QString &propName)
{
    ExecState *exec = execStateForPrincipal(caller);
    if (!exec) {
        return exception("No scripting context or frame");
    }

    JSObject *o = objectForId(objId);
    if (!o) {
        return exception("get on a non-object");
    }

    JSValue *v = o->get(exec, Identifier(propName));
    if (!exec->hadException() && v->isObject() && v->getObject()->implementsCall()) {
        // For a function we got OK, return a reference.
        return exportFuncRef(o, propName, true);
    } else {
        // straight return for other stuff or failure
        return handleReturn(exec, v);
    }
}

bool ScriptableOperations::put(ScriptableExtension *caller, quint64 objId,
                               const QString &propName, const QVariant &value)
{
    ExecState *exec = execStateForPrincipal(caller);
    if (!exec) {
        return false;    // ### debug warn?
    }

    JSObject *o = objectForId(objId);
    if (!o) {
        return false;
    }

    o->put(exec, Identifier(propName), importValue(exec, value, false));
    if (!exec->hadException()) {
        return true;
    } else {
        exec->clearException();
        return false;
    }
}

bool ScriptableOperations::removeProperty(ScriptableExtension *caller,
        quint64 objId, const QString &propName)
{
    ExecState *exec = execStateForPrincipal(caller);
    if (!exec) {
        return false;    // ### debug warn?
    }

    JSObject *o = objectForId(objId);
    if (!o) {
        return false;
    }

    bool ok = o->deleteProperty(exec, Identifier(propName));
    if (exec->hadException()) {
        exec->clearException();
        ok = false;
    }
    return ok;
}

bool ScriptableOperations::enumerateProperties(ScriptableExtension *caller,
        quint64 objId, QStringList *result)
{
    ExecState *exec = execStateForPrincipal(caller);
    if (!exec) {
        return false;    // ### debug warn?
    }

    JSObject *o = objectForId(objId);
    if (!o) {
        return false;
    }

    PropertyNameArray pa;
    o->getPropertyNames(exec, pa);

    for (int i = 0; i < pa.size(); ++i) {
        result->append(pa[i].qstring());
    }
    return true;
}

KHTMLPart *ScriptableOperations::partForPrincipal(ScriptableExtension *caller)
{
    // We implement our security checks by delegating to the KHTMLPart corresponding
    // to the given plugin's principal (which is the KHTMLPart owning it), and letting
    // the underlying implementation perform them (which it has to anyway)

    if (KHTMLPartScriptable *o = qobject_cast<KHTMLPartScriptable *>(caller)) {
        return o->m_part;
    } else {
        // We always set the host on child extensions.
        return partForPrincipal(caller->host());
    }
}

ExecState *ScriptableOperations::execStateForPrincipal(ScriptableExtension *caller)
{
    KHTMLPart *part = partForPrincipal(caller);

    if (!part) {
        return nullptr;
    }

    KJSProxy *proxy = KJSProxy::proxy(part);
    if (!proxy) {
        return nullptr;
    }

    KJS::Interpreter *i = proxy->interpreter();
    if (!i) {
        return nullptr;
    }

    return i->globalExec();
}

void ScriptableOperations::acquire(quint64 objId)
{
    JSObject *ptr = objectForId(objId);

    if (ptr) {
        ++(*exportedObjects())[ptr];
    } else {
        assert(false);
    }
}

void ScriptableOperations::release(quint64 objId)
{
    JSObject *ptr = objectForId(objId);

    if (ptr) {
        int newRC = --(*exportedObjects())[ptr];
        if (newRC == 0) {
            exportedObjects()->remove(ptr);
        }
    } else {
        assert(false);
    }
}

JSObject *ScriptableOperations::objectForId(quint64 objId)
{
    JSObject *ptr = reinterpret_cast<JSObject *>(objId);

    // Verify the pointer against the exports table for paranoia.
    if (exportedObjects()->contains(ptr)) {
        return ptr;
    } else {
        assert(false);
        return nullptr;
    }
}

void ScriptableOperations::mark()
{
    QHash<JSObject *, int> *exp = exportedObjects();

    for (QHash<JSObject *, int>::iterator i = exp->begin(); i != exp->end(); ++i) {
        JSObject *o = i.key();
        if (i.value() && !o->marked()) {
            o->mark();
        }
    }
}

//-----------------------------------------------------------------------------
// per-part stuff.

KHTMLPartScriptable::KHTMLPartScriptable(KHTMLPart *part):
    ScriptableExtension(part), m_part(part)
{
}

KJS::Interpreter *KHTMLPartScriptable::interpreter()
{
    KJSProxy *proxy = KJSProxy::proxy(m_part);
    if (!proxy) {
        return nullptr;
    }

    return proxy->interpreter();
}

QVariant KHTMLPartScriptable::rootObject()
{
    if (KJS::Interpreter *i = interpreter()) {
        return ScriptableOperations::exportObject(i->globalObject(), true);
    }

    return scriptableNull();
}

QVariant KHTMLPartScriptable::encloserForKid(KParts::ScriptableExtension *kid)
{
    ReadOnlyPart *childPart = qobject_cast<ReadOnlyPart *>(kid->parent());

    KJS::Interpreter *i = interpreter();
    if (!childPart || !i) {
        return scriptableNull();
    }

    khtml::ChildFrame *f = m_part->frame(childPart);

    if (!f) {
        qCWarning(KHTML_LOG) << "unable to find frame. Huh?";
        return scriptableNull();
    }

    // ### should this deal with fake window objects for iframes?
    // ### this should never actually get an iframe once iframes are fixed
    if (!f->m_partContainerElement.isNull()) {
        return ScriptableOperations::exportValue(
                   getDOMNode(i->globalExec(), f->m_partContainerElement.data()), true);
    }

    qCWarning(KHTML_LOG) << "could not find the part container";
    return scriptableNull();
}

// For paranoia: forward to ScriptOperations
void KHTMLPartScriptable::acquire(quint64 objid)
{
    ScriptableOperations::self()->acquire(objid);
}

void KHTMLPartScriptable::release(quint64 objid)
{
    ScriptableOperations::self()->release(objid);
}

QVariant KHTMLPartScriptable::evaluateScript(ScriptableExtension *caller,
        quint64 contextObjectId,
        const QString &code,
        ScriptLanguage lang)
{
    // qCDebug(KHTML_LOG) << code;

    if (lang != ECMAScript) {
        return exception("unsupported language");
    }

    KHTMLPart *callingHtmlPart = ScriptableOperations::partForPrincipal(caller);
    if (!callingHtmlPart) {
        return exception("failed to resolve principal");
    }

    // Figure out the object we want to access, and its corresponding part.
    JSObject *o = ScriptableOperations::objectForId(contextObjectId);
    if (!o) {
        return exception("invalid object");
    }

    DOM::NodeImpl *node = toNode(o);

    // Presently, we only permit node contexts here.
    // ### TODO: window contexts?
    if (!node) {
        return exception("non-Node context");
    }

    KHTMLPart *targetPart = node->document()->part();

    if (!targetPart) {
        return exception("failed to resolve destination principal");
    }

    if (!targetPart->checkFrameAccess(callingHtmlPart)) {
        return exception("XSS check failed");
    }

    // wheee..
    targetPart->executeScript(DOM::Node(node), code);

    // ### TODO: Return value. Which is a completely different kind of QVariant.
    // might just want to go to kJSProxy directly

    return scriptableNull();
}

bool KHTMLPartScriptable::isScriptLanguageSupported(ScriptLanguage lang) const
{
    return lang == ECMAScript;
}

bool KHTMLPartScriptable::setException(ScriptableExtension * /*caller*/,
                                       const QString &message)
{
    qCWarning(KHTML_LOG) << "ignoring:" << message;
    return false;
}

} // namespace KJS