qtdeclarative/qmljs_runtime.cpp

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#include "debugging.h"
#include "qmljs_runtime.h"
#include "qv4object.h"
#include "qv4ir_p.h"
#include "qv4objectproto.h"
#include "qv4globalobject.h"
#include "private/qlocale_tools_p.h"

#include <QtCore/qmath.h>
#include <QtCore/qnumeric.h>
#include <QtCore/QDebug>
#include <cstdio>
#include <cassert>
#include <typeinfo>
#include <stdlib.h>

#include "3rdparty/double-conversion/double-conversion.h"

namespace QQmlJS {
namespace VM {

QString numberToString(double num, int radix = 10)
{
    if (std::isnan(num)) {
        return QStringLiteral("NaN");
    } else if (qIsInf(num)) {
        return QLatin1String(num < 0 ? "-Infinity" : "Infinity");
    }

    if (radix == 10) {
        char str[100];
        double_conversion::StringBuilder builder(str, sizeof(str));
        double_conversion::DoubleToStringConverter::EcmaScriptConverter().ToShortest(num, &builder);
        return QString::fromLatin1(builder.Finalize());
    }

    QString str;
    bool negative = false;

    if (num < 0) {
        negative = true;
        num = -num;
    }

    double frac = num - ::floor(num);
    num = Value::toInteger(num);

    do {
        char c = (char)::fmod(num, radix);
        c = (c < 10) ? (c + '0') : (c - 10 + 'a');
        str.prepend(QLatin1Char(c));
        num = ::floor(num / radix);
    } while (num != 0);

    if (frac != 0) {
        str.append(QLatin1Char('.'));
        do {
            frac = frac * radix;
            char c = (char)::floor(frac);
            c = (c < 10) ? (c + '0') : (c - 10 + 'a');
            str.append(QLatin1Char(c));
            frac = frac - ::floor(frac);
        } while (frac != 0);
    }

    if (negative)
        str.prepend(QLatin1Char('-'));

    return str;
}

extern "C" {

Value __qmljs_init_closure(VM::Function *clos, ExecutionContext *ctx)
{
    assert(clos);
    return Value::fromObject(ctx->engine->newScriptFunction(ctx, clos));
}

Function *__qmljs_register_function(ExecutionContext *ctx, String *name,
                                    bool hasDirectEval,
                                    bool usesArgumentsObject, bool isStrict,
                                    bool hasNestedFunctions,
                                    String **formals, unsigned formalCount,
                                    String **locals, unsigned localCount)
{
    Function *f = ctx->engine->newFunction(name ? name->toQString() : QString());

    f->hasDirectEval = hasDirectEval;
    f->usesArgumentsObject = usesArgumentsObject;
    f->isStrict = isStrict;
    f->hasNestedFunctions = hasNestedFunctions;

    for (unsigned i = 0; i < formalCount; ++i)
        if (formals[i])
            f->formals.append(formals[i]->toQString());
    for (unsigned i = 0; i < localCount; ++i)
        if (locals[i])
            f->locals.append(locals[i]->toQString());

    return f;
}

Value __qmljs_string_literal_undefined(ExecutionContext *ctx)
{
    return Value::fromString(ctx->engine->identifier(QStringLiteral("undefined")));
}

Value __qmljs_string_literal_null(ExecutionContext *ctx)
{
    return Value::fromString(ctx->engine->identifier(QStringLiteral("null")));
}

Value __qmljs_string_literal_true(ExecutionContext *ctx)
{
    return Value::fromString(ctx->engine->identifier(QStringLiteral("true")));
}

Value __qmljs_string_literal_false(ExecutionContext *ctx)
{
    return Value::fromString(ctx->engine->identifier(QStringLiteral("false")));
}

Value __qmljs_string_literal_object(ExecutionContext *ctx)
{
    return Value::fromString(ctx->engine->identifier(QStringLiteral("object")));
}

Value __qmljs_string_literal_boolean(ExecutionContext *ctx)
{
    return Value::fromString(ctx->engine->identifier(QStringLiteral("boolean")));
}

Value __qmljs_string_literal_number(ExecutionContext *ctx)
{
    return Value::fromString(ctx->engine->identifier(QStringLiteral("number")));
}

Value __qmljs_string_literal_string(ExecutionContext *ctx)
{
    return Value::fromString(ctx->engine->identifier(QStringLiteral("string")));
}

Value __qmljs_string_literal_function(ExecutionContext *ctx)
{
    return Value::fromString(ctx->engine->identifier(QStringLiteral("function")));
}

Value __qmljs_delete_subscript(ExecutionContext *ctx, Value base, Value index)
{
    if (Object *o = base.asObject()) {
        uint n = UINT_MAX;
        if (index.isInteger())
            n = index.integerValue();
        else if (index.isDouble())
            n = index.doubleValue();
        if (n < UINT_MAX)
            return Value::fromBoolean(o->__delete__(ctx, n));
    }

    String *name = index.toString(ctx);
    return __qmljs_delete_member(ctx, base, name);
}

Value __qmljs_delete_member(ExecutionContext *ctx, Value base, String *name)
{
    Value obj = base.toObject(ctx);
    return Value::fromBoolean(obj.objectValue()->__delete__(ctx, name));
}

Value __qmljs_delete_name(ExecutionContext *ctx, String *name)
{
    return Value::fromBoolean(ctx->deleteProperty(name));
}

Value __qmljs_add_helper(Value left, Value right, ExecutionContext *ctx)
{
    Value pleft = __qmljs_to_primitive(left, ctx, PREFERREDTYPE_HINT);
    Value pright = __qmljs_to_primitive(right, ctx, PREFERREDTYPE_HINT);
    if (pleft.isString() || pright.isString()) {
        if (!pleft.isString())
            pleft = __qmljs_to_string(pleft, ctx);
        if (!pright.isString())
            pright = __qmljs_to_string(pright, ctx);
        String *string = __qmljs_string_concat(ctx, pleft.stringValue(), pright.stringValue());
        return Value::fromString(string);
    }
    double x = __qmljs_to_number(pleft, ctx);
    double y = __qmljs_to_number(pright, ctx);
    return Value::fromDouble(x + y);
}

Value __qmljs_instanceof(Value left, Value right, ExecutionContext *ctx)
{
    if (FunctionObject *function = right.asFunctionObject()) {
        bool r = function->hasInstance(ctx, left);
        return Value::fromBoolean(r);
    }

    return __qmljs_throw_type_error(ctx);
}

Value __qmljs_in(Value left, Value right, ExecutionContext *ctx)
{
    if (right.isObject()) {
        String *s = left.toString(ctx);
        bool r = right.objectValue()->__hasProperty__(ctx, s);
        return Value::fromBoolean(r);
    } else {
        return __qmljs_throw_type_error(ctx);
    }
}

void __qmljs_inplace_bit_and_name(Value value, String *name, ExecutionContext *ctx)
{
    ctx->inplaceBitOp(value, name, __qmljs_bit_and);
}

void __qmljs_inplace_bit_or_name(Value value, String *name, ExecutionContext *ctx)
{
    ctx->inplaceBitOp(value, name, __qmljs_bit_or);
}

void __qmljs_inplace_bit_xor_name(Value value, String *name, ExecutionContext *ctx)
{
    ctx->inplaceBitOp(value, name, __qmljs_bit_xor);
}

void __qmljs_inplace_add_name(Value value, String *name, ExecutionContext *ctx)
{
    ctx->inplaceBitOp(value, name, __qmljs_add);
}

void __qmljs_inplace_sub_name(Value value, String *name, ExecutionContext *ctx)
{
    ctx->inplaceBitOp(value, name, __qmljs_sub);
}

void __qmljs_inplace_mul_name(Value value, String *name, ExecutionContext *ctx)
{
    ctx->inplaceBitOp(value, name, __qmljs_mul);
}

void __qmljs_inplace_div_name(Value value, String *name, ExecutionContext *ctx)
{
    ctx->inplaceBitOp(value, name, __qmljs_div);
}

void __qmljs_inplace_mod_name(Value value, String *name, ExecutionContext *ctx)
{
    ctx->inplaceBitOp(value, name, __qmljs_mod);
}

void __qmljs_inplace_shl_name(Value value, String *name, ExecutionContext *ctx)
{
    ctx->inplaceBitOp(value, name, __qmljs_shl);
}

void __qmljs_inplace_shr_name(Value value, String *name, ExecutionContext *ctx)
{
    ctx->inplaceBitOp(value, name, __qmljs_shr);
}

void __qmljs_inplace_ushr_name(Value value, String *name, ExecutionContext *ctx)
{
    ctx->inplaceBitOp(value, name, __qmljs_ushr);
}

void __qmljs_inplace_bit_and_element(Value base, Value index, Value value, ExecutionContext *ctx)
{
    Object *obj = base.toObject(ctx).objectValue();
    obj->inplaceBinOp(value, index, __qmljs_bit_and, ctx);
}

void __qmljs_inplace_bit_or_element(Value base, Value index, Value value, ExecutionContext *ctx)
{
    Object *obj = base.toObject(ctx).objectValue();
    obj->inplaceBinOp(value, index, __qmljs_bit_or, ctx);
}

void __qmljs_inplace_bit_xor_element(Value base, Value index, Value value, ExecutionContext *ctx)
{
    Object *obj = base.toObject(ctx).objectValue();
    obj->inplaceBinOp(value, index, __qmljs_bit_xor, ctx);
}

void __qmljs_inplace_add_element(Value base, Value index, Value value, ExecutionContext *ctx)
{
    Object *obj = base.toObject(ctx).objectValue();
    obj->inplaceBinOp(value, index, __qmljs_add, ctx);
}

void __qmljs_inplace_sub_element(Value base, Value index, Value value, ExecutionContext *ctx)
{
    Object *obj = base.toObject(ctx).objectValue();
    obj->inplaceBinOp(value, index, __qmljs_sub, ctx);
}

void __qmljs_inplace_mul_element(Value base, Value index, Value value, ExecutionContext *ctx)
{
    Object *obj = base.toObject(ctx).objectValue();
    obj->inplaceBinOp(value, index, __qmljs_mul, ctx);
}

void __qmljs_inplace_div_element(Value base, Value index, Value value, ExecutionContext *ctx)
{
    Object *obj = base.toObject(ctx).objectValue();
    obj->inplaceBinOp(value, index, __qmljs_div, ctx);
}

void __qmljs_inplace_mod_element(Value base, Value index, Value value, ExecutionContext *ctx)
{
    Object *obj = base.toObject(ctx).objectValue();
    obj->inplaceBinOp(value, index, __qmljs_mod, ctx);
}

void __qmljs_inplace_shl_element(Value base, Value index, Value value, ExecutionContext *ctx)
{
    Object *obj = base.toObject(ctx).objectValue();
    obj->inplaceBinOp(value, index, __qmljs_shl, ctx);
}

void __qmljs_inplace_shr_element(Value base, Value index, Value value, ExecutionContext *ctx)
{
    Object *obj = base.toObject(ctx).objectValue();
    obj->inplaceBinOp(value, index, __qmljs_shr, ctx);
}

void __qmljs_inplace_ushr_element(Value base, Value index, Value value, ExecutionContext *ctx)
{
    Object *obj = base.toObject(ctx).objectValue();
    obj->inplaceBinOp(value, index, __qmljs_ushr, ctx);
}

void __qmljs_inplace_bit_and_member(Value value, Value base, String *name, ExecutionContext *ctx)
{
    Object *o = base.toObject(ctx).objectValue();
    o->inplaceBinOp(value, name, __qmljs_bit_and, ctx);
}

void __qmljs_inplace_bit_or_member(Value value, Value base, String *name, ExecutionContext *ctx)
{
    Object *o = base.toObject(ctx).objectValue();
    o->inplaceBinOp(value, name, __qmljs_bit_or, ctx);
}

void __qmljs_inplace_bit_xor_member(Value value, Value base, String *name, ExecutionContext *ctx)
{
    Object *o = base.toObject(ctx).objectValue();
    o->inplaceBinOp(value, name, __qmljs_bit_xor, ctx);
}

void __qmljs_inplace_add_member(Value value, Value base, String *name, ExecutionContext *ctx)
{
    Object *o = base.toObject(ctx).objectValue();
    o->inplaceBinOp(value, name, __qmljs_add, ctx);
}

void __qmljs_inplace_sub_member(Value value, Value base, String *name, ExecutionContext *ctx)
{
    Object *o = base.toObject(ctx).objectValue();
    o->inplaceBinOp(value, name, __qmljs_sub, ctx);
}

void __qmljs_inplace_mul_member(Value value, Value base, String *name, ExecutionContext *ctx)
{
    Object *o = base.toObject(ctx).objectValue();
    o->inplaceBinOp(value, name, __qmljs_mul, ctx);
}

void __qmljs_inplace_div_member(Value value, Value base, String *name, ExecutionContext *ctx)
{
    Object *o = base.toObject(ctx).objectValue();
    o->inplaceBinOp(value, name, __qmljs_div, ctx);
}

void __qmljs_inplace_mod_member(Value value, Value base, String *name, ExecutionContext *ctx)
{
    Object *o = base.toObject(ctx).objectValue();
    o->inplaceBinOp(value, name, __qmljs_mod, ctx);
}

void __qmljs_inplace_shl_member(Value value, Value base, String *name, ExecutionContext *ctx)
{
    Object *o = base.toObject(ctx).objectValue();
    o->inplaceBinOp(value, name, __qmljs_shl, ctx);
}

void __qmljs_inplace_shr_member(Value value, Value base, String *name, ExecutionContext *ctx)
{
    Object *o = base.toObject(ctx).objectValue();
    o->inplaceBinOp(value, name, __qmljs_shr, ctx);
}

void __qmljs_inplace_ushr_member(Value value, Value base, String *name, ExecutionContext *ctx)
{
    Object *o = base.toObject(ctx).objectValue();
    o->inplaceBinOp(value, name, __qmljs_ushr, ctx);
}

String *__qmljs_string_from_utf8(ExecutionContext *ctx, const char *s)
{
    return ctx->engine->newString(QString::fromUtf8(s));
}

String *__qmljs_identifier_from_utf8(ExecutionContext *ctx, const char *s)
{
    return ctx->engine->identifier(QString::fromUtf8(s));
}

int __qmljs_string_length(ExecutionContext *, String *string)
{
    return string->toQString().length();
}

double __qmljs_string_to_number(const String *string)
{
    QString s = string->toQString();
    s = s.trimmed();
    if (s.startsWith(QLatin1String("0x")) || s.startsWith(QLatin1String("0X")))
        return s.toLong(0, 16);
    bool ok;
    QByteArray ba = s.toLatin1();
    const char *begin = ba.constData();
    const char *end = 0;
    double d = qstrtod(begin, &end, &ok);
    if (end - begin != ba.size()) {
        if (ba == "Infinity" || ba == "+Infinity")
            d = INFINITY;
        else if (ba == "-Infinity")
            d = -INFINITY;
        else
            d = nan("");
    }
    return d;
}

Value __qmljs_string_from_number(ExecutionContext *ctx, double number)
{
    String *string = ctx->engine->newString(numberToString(number, 10));
    return Value::fromString(string);
}

Bool __qmljs_string_compare(ExecutionContext *, String *left, String *right)
{
    return left->toQString() < right->toQString();
}

Bool __qmljs_string_equal(String *left, String *right)
{
    return left->isEqualTo(right);
}

String *__qmljs_string_concat(ExecutionContext *ctx, String *first, String *second)
{
    return ctx->engine->newString(first->toQString() + second->toQString());
}

Bool __qmljs_is_function(Value value)
{
    return value.objectValue()->asFunctionObject() != 0;
}

Value __qmljs_object_default_value(ExecutionContext *ctx, Value object, int typeHint)
{
    if (typeHint == PREFERREDTYPE_HINT) {
        if (object.asDateObject())
            typeHint = STRING_HINT;
        else
            typeHint = NUMBER_HINT;
    }

    String *meth1 = ctx->engine->identifier("toString");
    String *meth2 = ctx->engine->identifier("valueOf");

    if (typeHint == NUMBER_HINT)
        qSwap(meth1, meth2);

    assert(object.isObject());
    Object *oo = object.objectValue();

    Value conv = oo->__get__(ctx, meth1);
    if (Object *o = conv.asObject()) {
        Value r = o->call(ctx, object, 0, 0);
        if (r.isPrimitive())
            return r;
    }

    conv = oo->__get__(ctx, meth2);
    if (Object *o = conv.asObject()) {
        Value r = o->call(ctx, object, 0, 0);
        if (r.isPrimitive())
            return r;
    }

    ctx->throwTypeError();
    return Value::undefinedValue();
}

Value __qmljs_throw_type_error(ExecutionContext *ctx)
{
    ctx->throwTypeError();
    return Value::undefinedValue();
}

Value __qmljs_new_object(ExecutionContext *ctx)
{
    return Value::fromObject(ctx->engine->newObject());
}

Value __qmljs_new_boolean_object(ExecutionContext *ctx, bool boolean)
{
    Value value = Value::fromBoolean(boolean);
    return Value::fromObject(ctx->engine->newBooleanObject(value));
}

Value __qmljs_new_number_object(ExecutionContext *ctx, double number)
{
    Value value = Value::fromDouble(number);
    return Value::fromObject(ctx->engine->newNumberObject(value));
}

Value __qmljs_new_string_object(ExecutionContext *ctx, String *string)
{
    Value value = Value::fromString(string);
    return Value::fromObject(ctx->engine->newStringObject(ctx, value));
}

void __qmljs_set_property(ExecutionContext *ctx, Value object, String *name, Value value)
{
    if (! object.isObject())
        object = __qmljs_to_object(object, ctx);
    object.objectValue()->__put__(ctx, name, value);
}

Value __qmljs_get_element(ExecutionContext *ctx, Value object, Value index)
{
    uint type = object.type();
    uint idx = index.asArrayIndex();

    if (type != Value::Object_Type) {
        if (type == Value::String_Type) {
            String *str = object.stringValue();
            if (idx >= (uint)str->toQString().length())
                return Value::undefinedValue();
            const QString s = str->toQString().mid(idx, 1);
            return Value::fromString(ctx, s);
        }

        object = __qmljs_to_object(object, ctx);
    }

    Object *o = object.objectValue();

    if (idx < UINT_MAX) {
        const PropertyDescriptor *p = o->array.nonSparseAt(idx);
        if (p && p->type == PropertyDescriptor::Data)
            return p->value;

        return o->__get__(ctx, idx);
    }

    String *name = index.toString(ctx);
    return o->__get__(ctx, name);
}

void __qmljs_set_element(ExecutionContext *ctx, Value object, Value index, Value value)
{
    if (!object.isObject())
        object = __qmljs_to_object(object, ctx);

    Object *o = object.objectValue();

    uint idx = index.asArrayIndex();
    if (idx < UINT_MAX) {
        PropertyDescriptor *p = o->array.nonSparseAtRef(idx);
        if (p && p->type == PropertyDescriptor::Data && p->isWritable()) {
            p->value = value;
            return;
        }
        o->__put__(ctx, idx, value);
        return;
    }

    String *name = index.toString(ctx);
    o->__put__(ctx, name, value);
}

Value __qmljs_foreach_iterator_object(Value in, ExecutionContext *ctx)
{
    if (!in.isNull() && !in.isUndefined())
        in = __qmljs_to_object(in, ctx);
    Object *it = ctx->engine->newForEachIteratorObject(ctx, in.asObject());
    return Value::fromObject(it);
}

Value __qmljs_foreach_next_property_name(Value foreach_iterator)
{
    assert(foreach_iterator.isObject());

    ForEachIteratorObject *it = static_cast<ForEachIteratorObject *>(foreach_iterator.objectValue());
    assert(it->className() == QLatin1String("__ForEachIteratorObject"));

    return it->nextPropertyName();
}


void __qmljs_set_activation_property(ExecutionContext *ctx, String *name, Value value)
{
    ctx->setProperty(name, value);
}

Value __qmljs_get_property(ExecutionContext *ctx, Value object, String *name)
{
    if (object.isObject()) {
        return object.objectValue()->__get__(ctx, name);
    } else if (object.isString() && name->isEqualTo(ctx->engine->id_length)) {
        return Value::fromInt32(object.stringValue()->toQString().length());
    } else {
        object = __qmljs_to_object(object, ctx);

        if (object.isObject()) {
            return object.objectValue()->__get__(ctx, name);
        } else {
            ctx->throwTypeError();
            return Value::undefinedValue();
        }
    }
}

Value __qmljs_get_activation_property(ExecutionContext *ctx, String *name)
{
    return ctx->getProperty(name);
}

Value __qmljs_get_thisObject(ExecutionContext *ctx)
{
    return ctx->thisObject;
}

uint __qmljs_equal(Value x, Value y, ExecutionContext *ctx)
{
    if (x.type() == y.type()) {
        switch (x.type()) {
        case Value::Undefined_Type:
            return true;
        case Value::Null_Type:
            return true;
        case Value::Boolean_Type:
            return x.booleanValue() == y.booleanValue();
            break;
        case Value::Integer_Type:
            return x.integerValue() == y.integerValue();
        case Value::String_Type:
            return x.stringValue()->isEqualTo(y.stringValue());
        case Value::Object_Type:
            return x.objectValue() == y.objectValue();
        default: // double
            return x.doubleValue() == y.doubleValue();
        }
        // unreachable
    } else {
        if (x.isNumber() && y.isNumber())
            return x.asDouble() == y.asDouble();
        if (x.isNull() && y.isUndefined()) {
            return true;
        } else if (x.isUndefined() && y.isNull()) {
            return true;
        } else if (x.isNumber() && y.isString()) {
            Value ny = Value::fromDouble(__qmljs_to_number(y, ctx));
            return __qmljs_equal(x, ny, ctx);
        } else if (x.isString() && y.isNumber()) {
            Value nx = Value::fromDouble(__qmljs_to_number(x, ctx));
            return __qmljs_equal(nx, y, ctx);
        } else if (x.isBoolean()) {
            Value nx = Value::fromDouble((double) x.booleanValue());
            return __qmljs_equal(nx, y, ctx);
        } else if (y.isBoolean()) {
            Value ny = Value::fromDouble((double) y.booleanValue());
            return __qmljs_equal(x, ny, ctx);
        } else if ((x.isNumber() || x.isString()) && y.isObject()) {
            Value py = __qmljs_to_primitive(y, ctx, PREFERREDTYPE_HINT);
            return __qmljs_equal(x, py, ctx);
        } else if (x.isObject() && (y.isNumber() || y.isString())) {
            Value px = __qmljs_to_primitive(x, ctx, PREFERREDTYPE_HINT);
            return __qmljs_equal(px, y, ctx);
        }
    }

    return false;
}

Value __qmljs_call_activation_property(ExecutionContext *context, String *name, Value *args, int argc)
{
    Object *base;
    Value func = context->getPropertyAndBase(name, &base);
    Object *o = func.asObject();
    if (!o)
        context->throwTypeError();

    Value thisObject = base ? Value::fromObject(base) : Value::undefinedValue();

    if (o == context->engine->evalFunction && name == context->engine->id_eval)
        return static_cast<EvalFunction *>(o)->evalCall(context, thisObject, args, argc, true);

    return o->call(context, thisObject, args, argc);
}

Value __qmljs_call_property(ExecutionContext *context, Value that, String *name, Value *args, int argc)
{
    Value thisObject = that;
    if (!thisObject.isObject())
        thisObject = __qmljs_to_object(thisObject, context);

    assert(thisObject.isObject());
    Object *baseObject = thisObject.objectValue();

    Value func = baseObject->__get__(context, name);
    Object *o = func.asObject();
    if (!o)
        context->throwTypeError();

    return o->call(context, thisObject, args, argc);
}

Value __qmljs_call_value(ExecutionContext *context, Value thisObject, Value func, Value *args, int argc)
{
    Object *o = func.asObject();
    if (!o)
        context->throwTypeError();
    return o->call(context, thisObject, args, argc);
}

Value __qmljs_construct_activation_property(ExecutionContext *context, String *name, Value *args, int argc)
{
    Value func = context->getProperty(name);
    return __qmljs_construct_value(context, func, args, argc);
}

Value __qmljs_construct_value(ExecutionContext *context, Value func, Value *args, int argc)
{
    if (FunctionObject *f = func.asFunctionObject())
        return f->construct(context, args, argc);

    context->throwTypeError();
    return Value::undefinedValue();
}

Value __qmljs_construct_property(ExecutionContext *context, Value base, String *name, Value *args, int argc)
{
    Value thisObject = base;
    if (!thisObject.isObject())
        thisObject = __qmljs_to_object(base, context);

    Value func = thisObject.objectValue()->__get__(context, name);
    if (FunctionObject *f = func.asFunctionObject())
        return f->construct(context, args, argc);

    context->throwTypeError();
    return Value::undefinedValue();
}

void __qmljs_throw(Value value, ExecutionContext *context)
{
    assert(!context->engine->unwindStack.isEmpty());

    if (context->engine->debugger)
        context->engine->debugger->aboutToThrow(&value);

    ExecutionEngine::ExceptionHandler &handler = context->engine->unwindStack.last();

    // clean up call contexts
    while (context != handler.context) {
        ExecutionContext *parent = context->parent;
        if (!context->withObject)
            context->leaveCallContext();
        context = parent;
    }

    context->engine->exception = value;

    longjmp(handler.stackFrame, 1);
}

void *__qmljs_create_exception_handler(ExecutionContext *context)
{
    context->engine->exception = Value::undefinedValue();
    context->engine->unwindStack.append(ExecutionEngine::ExceptionHandler());
    ExecutionEngine::ExceptionHandler &handler = context->engine->unwindStack.last();
    handler.context = context;
    return handler.stackFrame;
}

void __qmljs_delete_exception_handler(ExecutionContext *context)
{
    assert(!context->engine->unwindStack.isEmpty());

    context->engine->unwindStack.pop_back();
}

Value __qmljs_get_exception(ExecutionContext *context)
{
    return context->engine->exception;
}

Value __qmljs_builtin_typeof(Value value, ExecutionContext *ctx)
{
    switch (value.type()) {
    case Value::Undefined_Type:
        return __qmljs_string_literal_undefined(ctx);
        break;
    case Value::Null_Type:
        return __qmljs_string_literal_object(ctx);
        break;
    case Value::Boolean_Type:
        return __qmljs_string_literal_boolean(ctx);
        break;
    case Value::String_Type:
        return __qmljs_string_literal_string(ctx);
        break;
    case Value::Object_Type:
        if (__qmljs_is_callable(value, ctx))
            return __qmljs_string_literal_function(ctx);
        else
            return __qmljs_string_literal_object(ctx); // ### implementation-defined
        break;
    default:
        return __qmljs_string_literal_number(ctx);
        break;
    }
}

Value __qmljs_builtin_typeof_name(String *name, ExecutionContext *context)
{
    return __qmljs_builtin_typeof(context->getPropertyNoThrow(name), context);
}

Value __qmljs_builtin_typeof_member(Value base, String *name, ExecutionContext *context)
{
    Value obj = base.toObject(context);
    return __qmljs_builtin_typeof(obj.objectValue()->__get__(context, name), context);
}

Value __qmljs_builtin_typeof_element(Value base, Value index, ExecutionContext *context)
{
    String *name = index.toString(context);
    Value obj = base.toObject(context);
    return __qmljs_builtin_typeof(obj.objectValue()->__get__(context, name), context);
}

void __qmljs_builtin_throw(Value val, ExecutionContext *context)
{
    __qmljs_throw(val, context);
}

ExecutionContext *__qmljs_builtin_push_with_scope(Value o, ExecutionContext *ctx)
{
    Object *obj = __qmljs_to_object(o, ctx).asObject();
    return ctx->createWithScope(obj);
}

ExecutionContext *__qmljs_builtin_pop_scope(ExecutionContext *ctx)
{
    return ctx->popScope();
}

void __qmljs_builtin_declare_var(ExecutionContext *ctx, bool deletable, String *name)
{
    ctx->createMutableBinding(name, deletable);
}

void __qmljs_builtin_define_property(Value object, String *name, Value val, ExecutionContext *ctx)
{
    Object *o = object.asObject();
    assert(o);

    PropertyDescriptor pd;
    pd.value = val;
    pd.type = PropertyDescriptor::Data;
    pd.writable = PropertyDescriptor::Enabled;
    pd.enumberable = PropertyDescriptor::Enabled;
    pd.configurable = PropertyDescriptor::Enabled;
    o->__defineOwnProperty__(ctx, name, &pd);
}

void __qmljs_builtin_define_getter_setter(Value object, String *name, Value getter, Value setter, ExecutionContext *ctx)
{
    Object *o = object.asObject();
    assert(o);

    PropertyDescriptor pd;
    pd.get = getter.asFunctionObject();
    pd.set = setter.asFunctionObject();
    pd.type = PropertyDescriptor::Accessor;
    pd.writable = PropertyDescriptor::Undefined;
    pd.enumberable = PropertyDescriptor::Enabled;
    pd.configurable = PropertyDescriptor::Enabled;
    o->__defineOwnProperty__(ctx, name, &pd);
}

Value __qmljs_increment(Value value, ExecutionContext *ctx)
{
    TRACE1(value);

    if (value.isInteger())
        return Value::fromInt32(value.integerValue() + 1);

    double d = __qmljs_to_number(value, ctx);
    return Value::fromDouble(d + 1);
}

Value __qmljs_decrement(Value value, ExecutionContext *ctx)
{
    TRACE1(value);

    if (value.isInteger())
        return Value::fromInt32(value.integerValue() - 1);

    double d = __qmljs_to_number(value, ctx);
    return Value::fromDouble(d - 1);
}

} // extern "C"


} // namespace VM
} // namespace QQmlJS